Dynamical Degrees of Freedom of DNA Sequences by Local and Global Short-Range Prediction

Fractals ◽  
1997 ◽  
Vol 05 (01) ◽  
pp. 1-10
Author(s):  
M. Ragosta ◽  
C. Serio ◽  
M. T. Lanfredi ◽  
M. Macchiato
Keyword(s):  
Dna Sequences ◽  
Degrees Of Freedom ◽  
Nonlinear Process ◽  
Short Term ◽  
Chaotic Motions ◽  
Deterministic Systems ◽  
Predictive Skill ◽  
Low Dimensional ◽  
Dynamical Degrees ◽  
Insight Into

The dynamical properties of DNA sequence samples have been analyzed on the basis of a procedure able to distinguish chaos from randomness. The procedure relies on the concept of short-term (range) predictability of low-dimensional chaotic motions and can distinguish merely linear stochastic processes, e.g. fractional Brownian motion, from truly nonlinear deterministic systems. The method consists in obtaining forecasts on the basis of past events in the sequence. Two forecasting strategies are used. The local strategy views the sequence as the outcome of a nonlinear process, whereas the global approach considers the series as the outcome of a linear stochastic process. For both approaches, the predictive skill is computed and their inter-comparison allows us to get insight into and an understanding of the structure of DNA sequences. Nucleotidic sequences belonging to different taxonomic and functional groups have been analyzed. Different behaviors have been detected according to the existence of finite correlation dimension for specific groups of sequences.

scholarly journals Autoregressive models as a tool to discriminate chaos from randomness in geoelectrical time series: an application to earthquake prediction

1997 ◽  
Vol 40 (2) ◽  
Author(s):  
V. Cuomo ◽  
V. Lapenna ◽  
M. Macchiato ◽  
C. Serio
Keyword(s):  
Time Series ◽  
Degrees Of Freedom ◽  
Broad Class ◽  
Scaling Law ◽  
Power Spectra ◽  
Time Dynamics ◽  
Predictive Skill ◽  
Data Points ◽  
Typical Behaviour ◽  
Low Dimensional

The time dynamics of geoelectrical precursory time series has been investigated and a method to discriminate chaotic behaviour in geoelectrical precursory time series is proposed. It allows us to detect low-dimensional chaos when the only information about the time series comes from the time series themselves. The short-term predictability of these time series is evaluated using two possible forecasting approaches: global autoregressive approximation and local autoregressive approximation. The first views the data as a realization of a linear stochastic process, whereas the second considers the data points as a realization of a deterministic process, supposedly non-linear. The comparison of the predictive skill of the two techniques is a test to discriminate between low-dimensional chaos and random dynamics. The analyzed time series are geoelectrical measurements recorded by an automatic station located in Tito (Southern Italy) in one of the most seismic areas of the Mediterranean region. Our findings are that the global (linear) approach is superior to the local one and the physical system governing the phenomena of electrical nature is characterized by a large number of degrees of freedom. Power spectra of the filtered time series follow a P(f) = F-a scaling law: they exhibit the typical behaviour of a broad class of fractal stochastic processes and they are a signature of the self-organized systems.

A Bird in the Hand Isn’t Good for Long

2018 ◽  
Vol 65 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Stefan Scherbaum ◽  
Simon Frisch ◽  
Maja Dshemuchadse
Keyword(s):  
Decision Making ◽  
Cognitive Control ◽  
The Other ◽  
Decision Task ◽  
Short Term ◽  
Additional Time ◽  
Control Processes ◽  
Folk Wisdom ◽  
Study Participants ◽  
Insight Into

Abstract. Folk wisdom tells us that additional time to make a decision helps us to refrain from the first impulse to take the bird in the hand. However, the question why the time to decide plays an important role is still unanswered. Here we distinguish two explanations, one based on a bias in value accumulation that has to be overcome with time, the other based on cognitive control processes that need time to set in. In an intertemporal decision task, we use mouse tracking to study participants’ responses to options’ values and delays which were presented sequentially. We find that the information about options’ delays does indeed lead to an immediate bias that is controlled afterwards, matching the prediction of control processes needed to counter initial impulses. Hence, by using a dynamic measure, we provide insight into the processes underlying short-term oriented choices in intertemporal decision making.

scholarly journals Using syndromic measures of mortality to capture the dynamics of COVID-19 in Java, Indonesia, in the context of vaccination rollout

BMC Medicine ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Bimandra A. Djaafara ◽  
Charles Whittaker ◽  
Oliver J. Watson ◽  
Robert Verity ◽  
Nicholas F. Brazeau ◽  
...  
Keyword(s):  
Rural Areas ◽  
Vaccination Campaign ◽  
Control Measures ◽  
Additional Insight ◽  
Short Term ◽  
If Current ◽  
Vaccine Impact ◽  
Potential Impact ◽  
The Impact ◽  
Insight Into

Abstract Background As in many countries, quantifying COVID-19 spread in Indonesia remains challenging due to testing limitations. In Java, non-pharmaceutical interventions (NPIs) were implemented throughout 2020. However, as a vaccination campaign launches, cases and deaths are rising across the island. Methods We used modelling to explore the extent to which data on burials in Jakarta using strict COVID-19 protocols (C19P) provide additional insight into the transmissibility of the disease, epidemic trajectory, and the impact of NPIs. We assess how implementation of NPIs in early 2021 will shape the epidemic during the period of likely vaccine rollout. Results C19P burial data in Jakarta suggest a death toll approximately 3.3 times higher than reported. Transmission estimates using these data suggest earlier, larger, and more sustained impact of NPIs. Measures to reduce sub-national spread, particularly during Ramadan, substantially mitigated spread to more vulnerable rural areas. Given current trajectory, daily cases and deaths are likely to increase in most regions as the vaccine is rolled out. Transmission may peak in early 2021 in Jakarta if current levels of control are maintained. However, relaxation of control measures is likely to lead to a subsequent resurgence in the absence of an effective vaccination campaign. Conclusions Syndromic measures of mortality provide a more complete picture of COVID-19 severity upon which to base decision-making. The high potential impact of the vaccine in Java is attributable to reductions in transmission to date and dependent on these being maintained. Increases in control in the relatively short-term will likely yield large, synergistic increases in vaccine impact.

Specialist infantry and defence engagement

2020 ◽  
pp. bmjmilitary-2020-001455 ◽  
Author(s):  
Jonathan Blair Thomas Herron ◽  
K M Heil ◽  
D Reid
Keyword(s):  
Armed Forces ◽  
Short Term ◽  
The Future ◽  
Uk Government ◽  
The Uk ◽  
Insight Into

In 2015, the UK government published the National Strategic Defence and Security Review (SDSR) 2015, which laid out their vision for the future roles and structure of the UK Armed Forces. SDSR 2015 envisaged making broader use of the Armed Forces to support missions other than warfighting. One element of this would be to increase the scale and scope of defence engagement (DE) activities that the UK conducts overseas. DE activities traditionally involve the use of personnel and assets to help prevent conflict, build stability and gain influence with partner nations as part of a short-term training teams. This paper aimed to give an overview of the Specialist Infantry Group and its role in UK DE. It will explore the reasons why the SDSR 2015 recommended their formation as well as an insight into future tasks.

scholarly journals A chiral switchable photovoltaic ferroelectric 1D perovskite

2020 ◽  
Vol 6 (9) ◽  
pp. eaay4213 ◽  
Author(s):  
Yang Hu ◽  
Fred Florio ◽  
Zhizhong Chen ◽  
W. Adam Phelan ◽  
Maxime A. Siegler ◽  
...  
Keyword(s):  
Electric Fields ◽  
Mirror Symmetry ◽  
Degrees Of Freedom ◽  
Electrical Measurements ◽  
Temperature Dependent ◽  
Paraelectric Phase Transition ◽  
Strongly Coupled ◽  
Yield Phenomena ◽  
Hybrid Perovskite ◽  
Low Dimensional

Spin and valley degrees of freedom in materials without inversion symmetry promise previously unknown device functionalities, such as spin-valleytronics. Control of material symmetry with electric fields (ferroelectricity), while breaking additional symmetries, including mirror symmetry, could yield phenomena where chirality, spin, valley, and crystal potential are strongly coupled. Here we report the synthesis of a halide perovskite semiconductor that is simultaneously photoferroelectricity switchable and chiral. Spectroscopic and structural analysis, and first-principles calculations, determine the material to be a previously unknown low-dimensional hybrid perovskite (R)-(−)-1-cyclohexylethylammonium/(S)-(+)-1 cyclohexylethylammonium) PbI3. Optical and electrical measurements characterize its semiconducting, ferroelectric, switchable pyroelectricity and switchable photoferroelectric properties. Temperature dependent structural, dielectric and transport measurements reveal a ferroelectric-paraelectric phase transition. Circular dichroism spectroscopy confirms its chirality. The development of a material with such a combination of these properties will facilitate the exploration of phenomena such as electric field and chiral enantiomer–dependent Rashba-Dresselhaus splitting and circular photogalvanic effects.

scholarly journals Ab Initio Study of Ferroelectric Critical Size of SnTe Low-Dimensional Nanostructures

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 732 ◽  
Author(s):  
Takahiro Shimada ◽  
Koichiro Minaguro ◽  
Tao Xu ◽  
Jie Wang ◽  
Takayuki Kitamura
Keyword(s):  
Density Functional ◽  
Critical Size ◽  
Density Functional Theory Calculations ◽  
Cell Width ◽  
Functional Theory ◽  
Unit Cells ◽  
Principle Density Functional Theory ◽  
Low Dimensional ◽  
Insight Into ◽  
Ferroelectric Perovskite

Beyond a ferroelectric critical thickness of several nanometers existed in conventional ferroelectric perovskite oxides, ferroelectricity in ultimately thin dimensions was recently discovered in SnTe monolayers. This discovery suggests the possibility that SnTe can sustain ferroelectricity during further low-dimensional miniaturization. Here, we investigate a ferroelectric critical size of low-dimensional SnTe nanostructures such as nanoribbons (1D) and nanoflakes (0D) using first-principle density-functional theory calculations. We demonstrate that the smallest (one-unit-cell width) SnTe nanoribbon can sustain ferroelectricity and there is no ferroelectric critical size in the SnTe nanoribbons. On the other hand, the SnTe nanoflakes form a vortex of polarization and lose their toroidal ferroelectricity below the surface area of 4 × 4 unit cells (about 25 Å on one side). We also reveal the atomic and electronic mechanism of the absence or presence of critical size in SnTe low-dimensional nanostructures. Our result provides an insight into intrinsic ferroelectric critical size for low-dimensional chalcogenide layered materials.

scholarly journals Optimizing the structure and movement of a robotic bat with biological kinematic synergies

2018 ◽  
Vol 37 (10) ◽  
pp. 1233-1252 ◽  
Author(s):  
Jonathan Hoff ◽  
Alireza Ramezani ◽  
Soon-Jo Chung ◽  
Seth Hutchinson
Keyword(s):  
Principal Component Analysis ◽  
Topological Structure ◽  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Principal Component ◽  
Biologically Inspired ◽  
Wing Kinematics ◽  
Wing Motion ◽  
Kinematic Synergies ◽  
Low Dimensional

In this article, we present methods to optimize the design and flight characteristics of a biologically inspired bat-like robot. In previous, work we have designed the topological structure for the wing kinematics of this robot; here we present methods to optimize the geometry of this structure, and to compute actuator trajectories such that its wingbeat pattern closely matches biological counterparts. Our approach is motivated by recent studies on biological bat flight that have shown that the salient aspects of wing motion can be accurately represented in a low-dimensional space. Although bats have over 40 degrees of freedom (DoFs), our robot possesses several biologically meaningful morphing specializations. We use principal component analysis (PCA) to characterize the two most dominant modes of biological bat flight kinematics, and we optimize our robot’s parametric kinematics to mimic these. The method yields a robot that is reduced from five degrees of actuation (DoAs) to just three, and that actively folds its wings within a wingbeat period. As a result of mimicking synergies, the robot produces an average net lift improvesment of 89% over the same robot when its wings cannot fold.

Vortex-Induced Vibrations of a Rigid Cylinder on Non-Linear Elastic Supports

2006 ◽  
Author(s):  
S. Bourdier ◽  
J. R. Chaplin
Keyword(s):  
Circular Cylinder ◽  
Phase Flow ◽  
Linear Vibration ◽  
Chaotic Motions ◽  
Frequency Spectra ◽  
Elastic Supports ◽  
Linear Elastic ◽  
Vortex Induced Vibrations ◽  
Non Linear ◽  
Insight Into

The dynamics of vortex-induced vibrations of a rigid circular cylinder with structural non-linearities, introduced by means of discontinuities in the support system, are studied experimentally. The analysis of the measurements is carried out using non-linear vibration tools, i.e phase-flow portraits, frequency spectra, Lyapunov exponents and correlation dimensions, to provide an insight into the dynamical changes in the system brought about by restricting the motion. We show that chaotic motions can occur due to the structural non-linearities.

Chrysophycean Microfossils Provide New Insight into the Recent History of a Naturally Acidic Lake (Cone Pond, New Hampshire)

1987 ◽  
Vol 44 (9) ◽  
pp. 1584-1588 ◽  
Author(s):  
Katherine N. Gibson ◽  
John P. Smol ◽  
Jesse Ford
Keyword(s):  
New Hampshire ◽  
Early Spring ◽  
Recent Change ◽  
Fish Populations ◽  
Short Term ◽  
Acidic Lake ◽  
Lake Water Chemistry ◽  
History Of ◽  
Early Snowmelt ◽  
Insight Into

Cone Pond, New Hampshire, is an acidic (pH = 4.5) clearwater lake that is currently fishless. Historical records indicate declining fish populations between 1951 and 1966, but paleolimnological work using diatoms failed to find evidence for further recent acidification of this naturally acid site. We initiated new paleolimnological studies using mallomonadacean chrysophytes to further our understanding of Cone Pond's recent past. Our stratigraphic analyses indicate recent striking changes in the chrysophyte flora of this lake, with Mallomonas hindonii, a species only common in recently acidified lakes, replacing M. crassisquama, a cosmopolitan species that dominated the flora over the preceding 8000 yr; this recent change parallels the declines in fish populations. Because chrysophytes often bloom in early spring and are known, in other lakes, to experience changes in community composition before those expressed by the diatom community, a possibility is that chrysophytes track transient excursions of lake water chemistry associated with early snowmelt conditions. In this scenario, chrysophytes would respond to a constellation of specific short-term chemical changes including, but not restricted to, pH. Such pH associated changes could include changes in concentrations, speciation, or complexation of metals mobilized from the catchment or sediments, all of which are known to affect both chrysophytes and fish.

Athletes Play Through Pain—What Does That Mean for Rehabilitation Specialists?

2020 ◽  
Vol 29 (5) ◽  
pp. 640-649 ◽  
Author(s):  
Amy Barrette ◽  
Katherine Harman
Keyword(s):  
Well Being ◽  
Short Term ◽  
Semistructured Interviews ◽  
Sport Organization ◽  
The University ◽  
E Mail ◽  
Competitive Nature ◽  
And Training ◽  
Insight Into

Context: Pain in sport has been normalized to the point where athletes are expected to ignore pain and remain in the game despite the possible detrimental consequences associated with playing through pain. While rehabilitation specialists may not have an influence on an athlete’s competitive nature or the culture of risk they operate in, understanding the consequences of those factors on an athlete’s physical well-being is definitely in their area of responsibility. Objective: To explore the factors associated with the experiences of subelite athletes who play through pain in gymnastics, rowing, and speed skating. Design: The authors conducted semistructured interviews with subelite athletes, coaches, and rehabilitation specialists. They recruited coach participants through their provincial sport organization. Athletes of the recruited coaches who were recovering from a musculoskeletal injury and training for a major competition were then recruited. They also recruited rehabilitation specialists who were known to treat subelite athletes independently by e-mail. Setting: An observation session was conducted at the athlete’s training facility. Interviews were then conducted either in a room at the university or at a preferred sound-attenuated location suggested by the participant. Participants: The authors studied 5 coaches, 4 subelite athletes, and 3 rehabilitation specialists. Interventions: The authors photographed athletes during a practice shortly before an important competition, and we interviewed all the participants after that competition. Our photographs were used during the interview to stimulate discussion. Results: The participant interviews revealed 3 main themes related to playing through pain. They are: Listening to your body, Decision making, and Who decides. Conclusion: When subelite athletes, striving to be the best in their sport continue to train with the pain of an injury, performance is affected in the short-term and long-term consequences are also possible. Our study provides some insight into the contrasting forces that athletes balance as they decide to continue or to stop.

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