scholarly journals A dynamical systems characterization of atmospheric jet regimes

2021 ◽  
Vol 12 (1) ◽  
pp. 233-251
Author(s):  
Gabriele Messori ◽  
Nili Harnik ◽  
Erica Madonna ◽  
Orli Lachmy ◽  
Davide Faranda
Keyword(s):  
Dynamical Systems ◽  
Polar Front ◽  
Reanalysis Data ◽  
Jet Streams ◽  
Driving Mechanisms ◽  
Thermally Driven ◽  
Eddy Generation ◽  
Underlying Mechanisms ◽  
Jet Characteristics

Abstract. Atmospheric jet streams are typically separated into primarily “eddy-driven” (or polar-front) jets and primarily “thermally driven” (or subtropical) jets. Some regions also display “merged” jets, resulting from the (quasi-)collocation of the regions of eddy generation with the subtropical jet. The different locations and driving mechanisms of these jets arise from very different underlying mechanisms and result in very different jet characteristics. Here, we link the current understanding of dynamical jet maintenance mechanisms, mostly arising from conceptual or idealized models, to the phenomena observed in reanalysis data. We specifically focus on developing a unitary analysis framework grounded in dynamical systems theory, which may be applied to both idealized models and reanalysis, as well as allowing for direct intercomparison. Our results illustrate the effectiveness of dynamical systems indicators to diagnose jet regimes.

A Dynamical Systems Characterisation of Atmospheric Jet Regimes in a Simple Model and Reanalysis Data

2020 ◽  
Author(s):  
Nili Harnik ◽  
Gabriele Messori ◽  
Erica Madonna ◽  
Orly Lachmy ◽  
Davide Farranda
Keyword(s):  
Dynamical Systems ◽  
Polar Front ◽  
Reanalysis Data ◽  
Computationally Efficient ◽  
Jet Streams ◽  
Driving Mechanisms ◽  
Thermally Driven ◽  
Eddy Generation ◽  
Underlying Mechanisms ◽  
Jet Characteristics

<p>Atmospheric jet streams are typically separated into primarily "eddy-driven", or "polar-front" jets and primarily "thermally-driven", or "subtropical" jets. Some regions also display “merged” jets, resulting from the (quasi) co-location of the regions of eddy generation with the subtropical jet. The different location and driving mechanisms of the two jet structures, plus the intermediate “merged” jet, issue from very different underlying mechanisms, and result in very different jet characteristics. Here, we link our understanding of the dynamical jet maintenance mechanisms, mostly issuing from conceptual or idealised models, to the phenomena observed in reanalysis data. We specifically focus on developing a unitary analysis framework, grounded in dynamical systems theory, which may be applied to both the model and reanalysis data and allow for direct intercomparison. Our results provide a proof-of-concept for using dynamical systems indicators to diagnose jet regimes in a versatile, conceptually intuitive and computationally efficient fashion.</p>

scholarly journals A Dynamical Systems Characterisation of Atmospheric Jet Regimes

2020 ◽  
Author(s):  
Gabriele Messori ◽  
Nili Harnik ◽  
Erica Madonna ◽  
Orli Lachmy ◽  
Davide Faranda
Keyword(s):  
Dynamical Systems ◽  
Polar Front ◽  
Reanalysis Data ◽  
Computationally Efficient ◽  
Jet Streams ◽  
Driving Mechanisms ◽  
Thermally Driven ◽  
Idealised Model ◽  
Underlying Mechanisms ◽  
Jet Characteristics

Abstract. Atmospheric jet streams are typically separated into primarily eddy-driven, or polar-front jets and primarily thermally-driven, or "subtropical" jets. Some regions also display merged jets, resulting from the (quasi) co-location of the regions of eddy generation with the subtropical jet. The different locations and driving mechanisms of these jets issue from very different underlying mechanisms, and result in very different jet characteristics. Here, we link our understanding of the dynamical jet maintenance mechanisms, mostly issuing from conceptual or idealised models, to the phenomena observed in reanalysis data. We specifically focus on developing a unitary analysis framework, grounded in dynamical systems theory, which may be applied to both idealised model and reanalysis data, and allow for direct intercomparison. Our results provide a proof-of-concept for using dynamical systems indicators to diagnose jet regimes in a versatile, conceptually intuitive and computationally efficient fashion.

scholarly journals Cyclonic and anticyclonic contributions to atmospheric energetics

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Satoru Okajima ◽  
Hisashi Nakamura ◽  
Yohai Kaspi
Keyword(s):  
Storm Track ◽  
Mean Flow ◽  
Weather Variability ◽  
Jet Streams ◽  
Near Surface ◽  
Westerly Jet ◽  
Track Dynamics ◽  
New Findings ◽  
Atmospheric Energetics ◽  
Thermally Driven

AbstractMigratory cyclones and anticyclones account for most of the day-to-day weather variability in the extratropics. These transient eddies act to maintain the midlatitude jet streams by systematically transporting westerly momentum and heat. Yet, little is known about the separate contributions of cyclones and anticyclones to their interaction with the westerlies. Here, using a novel methodology for identifying cyclonic and anticyclonic vortices based on curvature, we quantify their separate contributions to atmospheric energetics and their feedback on the westerly jet streams as represented in Eulerian statistics. We show that climatological westerly acceleration by cyclonic vortices acts to dominantly reinforce the wintertime eddy-driven near-surface westerlies and associated cyclonic shear. Though less baroclinic and energetic, anticyclones still play an important role in transporting westerly momentum toward midlatitudes from the upper-tropospheric thermally driven jet core and carrying eddy energy downstream. These new findings have uncovered essential characteristics of atmospheric energetics, storm track dynamics and eddy-mean flow interaction.

scholarly journals Characterization of the Survival Influential Genes in Carcinogenesis

2021 ◽  
Vol 22 (9) ◽  
pp. 4384
Author(s):  
Divya Sahu ◽  
Yu-Lin Chang ◽  
Yin-Chen Lin ◽  
Chen-Ching Lin
Keyword(s):  
Cell Cycle ◽  
Cox Regression ◽  
Monte Carlo Algorithm ◽  
Functional Modules ◽  
Protective Genes ◽  
Cancer Types ◽  
Underlying Mechanisms ◽  
Patient Prognosis ◽  
Pan Cancer

The genes influencing cancer patient mortality have been studied by survival analysis for many years. However, most studies utilized them only to support their findings associated with patient prognosis: their roles in carcinogenesis have not yet been revealed. Herein, we applied an in silico approach, integrating the Cox regression model with effect size estimated by the Monte Carlo algorithm, to screen survival-influential genes in more than 6000 tumor samples across 16 cancer types. We observed that the survival-influential genes had cancer-dependent properties. Moreover, the functional modules formed by the harmful genes were consistently associated with cell cycle in 12 out of the 16 cancer types and pan-cancer, showing that dysregulation of the cell cycle could harm patient prognosis in cancer. The functional modules formed by the protective genes are more diverse in cancers; the most prevalent functions are relevant for immune response, implying that patients with different cancer types might develop different mechanisms against carcinogenesis. We also identified a harmful set of 10 genes, with potential as prognostic biomarkers in pan-cancer. Briefly, our results demonstrated that the survival-influential genes could reveal underlying mechanisms in carcinogenesis and might provide clues for developing therapeutic targets for cancers.

scholarly journals Transcriptome-based identification and characterization of genes responding to imidacloprid in Myzus persicae

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jianyu Meng ◽  
Xingjiang Chen ◽  
Changyu Zhang
Keyword(s):  
Genetic Basis ◽  
Expression Profiles ◽  
Control Measure ◽  
Effective Control ◽  
Agricultural Pest ◽  
Functional Classification ◽  
Quantitative Real Time Pcr ◽  
Underlying Mechanisms ◽  
Identification And Characterization

Abstract Myzus persicae is a serious and widespread agricultural pest, against which, imidacloprid remains an effective control measure. However, recent reports indicate that this aphid has evolved and developed resistance to imidacloprid. This study aimed to elucidate the underlying mechanisms and genetic basis of this resistance by conducting comparative transcriptomics studies on both imidacloprid-resistant (IR) and imidacloprid-susceptible (IS) M. persicae. The comparative analysis identified 252 differentially expressed genes (DEGs) among the IR and IS M. persicae transcriptomes. These candidate genes included 160 and 92 genes that were down- and up-regulated, respectively, in the imidacloprid-resistant strain. Using functional classification in the GO and KEGG databases, 187 DEGs were assigned to 303 functional subcategories and 100 DEGs were classified into 45 pathway groups. Moreover, several genes were associated with known insecticide targets, cuticle, metabolic processes, and oxidative phosphorylation. Quantitative real-time PCR of 10 DEGs confirmed the trends observed in the RNA sequencing expression profiles. These findings provide a valuable basis for further investigation into the complicated mechanisms of imidacloprid resistance in M. persicae.

A UNIFIED FRAMEWORK FOR SYNCHRONIZATION AND CONTROL OF DYNAMICAL SYSTEMS

1994 ◽  
Vol 04 (04) ◽  
pp. 979-998 ◽  
Author(s):  
CHAI WAH WU ◽  
LEON O. CHUA
Keyword(s):  
Dynamical Systems ◽  
Chaotic Systems ◽  
Main Tool ◽  
Lyapunov Stability Theory ◽  
Asymptotical Stability ◽  
Unified Framework ◽  
Partial Synchronization ◽  
Chua’S Oscillator ◽  
And Control

In this paper, we give a framework for synchronization of dynamical systems which unifies many results in synchronization and control of dynamical systems, in particular chaotic systems. We define concepts such as asymptotical synchronization, partial synchronization and synchronization error bounds. We show how asymptotical synchronization is related to asymptotical stability. The main tool we use to prove asymptotical stability and synchronization is Lyapunov stability theory. We illustrate how many previous results on synchronization and control of chaotic systems can be derived from this framework. We will also give a characterization of robustness of synchronization and show that master-slave asymptotical synchronization in Chua’s oscillator is robust.

Numerical characterization of nonlinear dynamical systems using parallel computing: The role of GPUs approach

2016 ◽  
Vol 37 ◽  
pp. 143-162 ◽  
Author(s):  
Filipe I. Fazanaro ◽  
Diogo C. Soriano ◽  
Ricardo Suyama ◽  
Marconi K. Madrid ◽  
José Raimundo de Oliveira ◽  
...  
Keyword(s):  
Parallel Computing ◽  
Dynamical Systems ◽  
Nonlinear Dynamical Systems ◽  
Nonlinear Dynamical ◽  
Numerical Characterization

Characterization of the morning transition from downslope to upslope winds and its connection with the nocturnal inversion breakup at the foot of a gentle slope

2021 ◽  
Author(s):  
Sofia Farina ◽  
Dino Zardi ◽  
Silvana Di Sabatino ◽  
Mattia Marchio ◽  
Francesco Barbano
Keyword(s):  
Salt Lake ◽  
Vertical Direction ◽  
Blow Down ◽  
Physical Mechanisms ◽  
Morning Transition ◽  
Thermally Driven ◽  
Slope Wind ◽  
Slope Flow ◽  
Nocturnal Inversion

<p>Thermally driven winds observed in complex terrain are characterized by a daily cycle dominated by two main phases: a diurnal phase in which winds blow upslope (anabatic), and a nocturnal one in which they revert their direction and blow down slope (katabatic). This alternating pattern also implies two transition phases, following sunrise and sunset respectively. </p><p>Here we study the up-slope component of the slope wind with a focus on the morning transition based on from the MATERHORN experiment, performed in Salt Lake Desert (Utah) between Fall 2012 and Spring 2013. </p><p>The analysis develops along three main paths of investigation. The first one is the selection of the suitable conditions for the study of the diurnal component and the characterization of the morning transition. The second one focuses on the deep analysis of the erosion of the nocturnal inversion at the foot of the slope in order to investigate the physical mechanisms driving it. And the third one consists in the comparison between the experimental data and the results of an analytical model (Zardi and Serafin, 2015). The study of the morning transition in the selected case studies allowed its characterization in terms of the relation with the solar radiation cycle, in terms of its seasonality and in terms of its propagation along the slope and along the vertical direction. Most of the results of this investigation are related to the identification of the main mechanisms of erosion of the nocturnal inversion at the foot of the slope and to its role to the beginning of the transition itself. Finally, it is shown how the above model can fairly reproduce the cycle between anabatic and katabatic flow and their intensity.</p><p>Zardi, D. and S. Serafin, 2015: An analytic solution for daily-periodic thermally-driven slope flow. Quart. J. Roy. Meteor. Soc., 141, 1968–1974.</p>

Abstract 344: Finding the Achilles’ heel of Muscle Giant---TALEN-mediated Gene-editing in Zebrafish Titin

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Yu-Huan Shih ◽  
Xiaolei Xu
Keyword(s):  
Alternative Splicing ◽  
Gene Editing ◽  
Muscle Development ◽  
Exon Skipping ◽  
Transcription Activator ◽  
Detailed Characterization ◽  
A Domains ◽  
Underlying Mechanisms ◽  
Sarcomere Assembly

Background: TITIN (TTN) has more than 300 exons and encodes a gigantic protein that is crucial for heart and muscle development. Mutations in TTN caused a variety of human diseases including cardiomyopathy and muscular dystrophy. Recently, dilated cardiomyopathy-associated mutations on TTN have been found more frequently in exons encoding A-band domains but less in exons encoding the N-terminal Z-disc domains, suggesting that mutations in different exons of TTN cause distinct consequences. To elucidate the underlying mechanisms, we leveraged the Transcription Activator-Like Effects Nuclease (TALEN) technology in zebrafish to introduce truncating mutations in different exons of ttn, and then study their effects on heart and somites. Results: We generated truncational mutations in different exons of zebrafish titins encoding Z-disc, N2B, Novex-3, and A domains, respectively. Because zebrafish contains two titin homologues, ttna and ttnb, we introduced mutations in both genes at the corresponding loci. While both Z-disc and A band mutations on ttna disrupted sarcomere assembly in heart and somites, Z-disc or A band mutations on ttnb only affect somites without affecting the heart. Interestingly, a Z-disc mutation on ttna resulted in milder phenotypes than an A-band mutation, while a Z-disc mutation on ttnb generated severer phenotypes than an A-band mutation. No phenotype was observed in the homozygous fish in either ttna-novex-3 or ttnb-N2B mutant fish. Conclusions: A spectrum of truncational mutations in ttna and ttnb has been generated in zebrafish using the TALEN technology. Mutations in different exons result in different phenotypes. Detailed characterization of these mutants and double mutants will be presented, which shall elicit distinct contribution of alternative splicing and exon skipping as two candidate mechanisms during pathogenesis of Titinopathies.

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