scholarly journals The Major Role of Eccentricity in the Evolution of Colliding Pulsar-Stellar Winds

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 277
Author(s):  
Maxim V. Barkov ◽  
Valenti Bosch-Ramon
Keyword(s):  
Large Scale ◽  
Binary Systems ◽  
Three Dimensional ◽  
Stellar Winds ◽  
Spatial And Temporal Scales ◽  
Stellar Outflows ◽  
Thermal Emitters ◽  
Pulsar Wind ◽  
First Time

Binary systems that host a massive star and a non-accreting pulsar can be powerful non-thermal emitters. The relativistic pulsar wind and the non-relativistic stellar outflows interact along the orbit, producing ultrarelativistic particles that radiate from radio to gamma rays. To properly characterize the physics of these sources, and better understand their emission and impact on the environment, careful modeling of the outflow interactions, spanning a broad range of spatial and temporal scales, is needed. Full three-dimensional approaches are very computationally expensive, but simpler approximate approaches, while still realistic at the semi-quantitative level, are available. We present here the results of calculations done with a quasi three-dimensional scheme to compute the evolution of the interacting flows in a region spanning in size up to a thousand times the size of the binary. In particular, we analyze for the first time the role of different eccentricities in the large scale evolution of the shocked flows. We find that the higher the eccentricity, the closer the flows behave like a one-side outflow, which becomes rather collimated for eccentricity values ≳0.75. The simulations also unveil that the pulsar and the stellar winds become fully mixed within the grid for low eccentricity systems, presenting a more stochastic behavior at large scales than in the highly eccentric systems.

scholarly journals Shell-crossing in a ΛCDM Universe

2020 ◽  
Vol 501 (1) ◽  
pp. L71-L75
Author(s):  
Cornelius Rampf ◽  
Oliver Hahn
Keyword(s):  
Dark Matter ◽  
Perturbation Theory ◽  
Large Scale ◽  
Cold Dark Matter ◽  
Three Dimensional ◽  
Random Initial Data ◽  
Recursion Relations ◽  
Indispensable Tool ◽  
First Time ◽  
Very High

ABSTRACT Perturbation theory is an indispensable tool for studying the cosmic large-scale structure, and establishing its limits is therefore of utmost importance. One crucial limitation of perturbation theory is shell-crossing, which is the instance when cold-dark-matter trajectories intersect for the first time. We investigate Lagrangian perturbation theory (LPT) at very high orders in the vicinity of the first shell-crossing for random initial data in a realistic three-dimensional Universe. For this, we have numerically implemented the all-order recursion relations for the matter trajectories, from which the convergence of the LPT series at shell-crossing is established. Convergence studies performed at large orders reveal the nature of the convergence-limiting singularities. These singularities are not the well-known density singularities at shell-crossing but occur at later times when LPT already ceased to provide physically meaningful results.

scholarly journals It’s All in the Reading

Arts ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 19
Author(s):  
Déirdre Kelly
Keyword(s):  
Contemporary Art ◽  
Mass Production ◽  
Large Scale ◽  
Book Production ◽  
Art Practice ◽  
The Arts ◽  
History Of ◽  
First Time ◽  
The City

It seems inherent in the nature of contemporary artist’s book production to continue to question the context for the genre in contemporary art practice, notwithstanding the medium’s potential for dissemination via mass production and an unquestionable advantage of portability for distribution. Artists, curators and editors operating in this sector look to create contexts for books in a variety of imaginative ways, through exhibition, commission, installations, performance and, of course as documentation. Broadening the discussion of the idea of the book within contemporary art practice, this paper examines the presence and role of book works within the context of the art biennale, in particular the Venice Art Biennale of which the 58th iteration (2019) is entitled ‘May You Live In Interesting Times’ and curated by Ralph Rugoff, with an overview of the independent International cultural offerings and the function of the ‘Book Pavilion’. Venetian museums and institutions continue to present vibrant diverse works within the arena of large-scale exhibitions, recognising the position that the book occupies in the history of the city. This year, the appearance for the first time, of ‘Book Biennale’, opens up a new and interesting dialogue, taking the measure of how the book is being promoted and its particular function for visual communication within the arts in Venice and beyond.

scholarly journals Plasticity of Sensorimotor Networks

2016 ◽  
Vol 23 (2) ◽  
pp. 185-196 ◽  
Author(s):  
Ethan R. Buch ◽  
Sook-Lei Liew ◽  
Leonardo G. Cohen
Keyword(s):  
Motor System ◽  
Degrees Of Freedom ◽  
Large Scale ◽  
System Organization ◽  
Basic Feature ◽  
Intrinsic Variability ◽  
Spatial And Temporal Scales ◽  
Large Scale Network ◽  
Scale Network

Redundancy is an important feature of the motor system, as abundant degrees of freedom are prominent at every level of organization across the central and peripheral nervous systems, and musculoskeletal system. This basic feature results in a system that is both flexible and robust, and which can be sustainably adapted through plasticity mechanisms in response to intrinsic organismal changes and dynamic environments. While much early work of motor system organization has focused on synaptic-based plasticity processes that are driven via experience, recent investigations of neuron–glia interactions, epigenetic mechanisms and large-scale network dynamics have revealed a plethora of plasticity mechanisms that support motor system organization across multiple, overlapping spatial and temporal scales. Furthermore, an important role of these mechanisms is the regulation of intrinsic variability. Here, we review several of these mechanisms and discuss their potential role in neurorehabilitation.

The trajectory of geomorphology

2010 ◽  
Vol 34 (3) ◽  
pp. 265-286 ◽  
Author(s):  
Michael Church
Keyword(s):  
Twentieth Century ◽  
Large Scale ◽  
Earth Science ◽  
Dominant Role ◽  
Historical Interpretation ◽  
Spatial And Temporal Scales ◽  
Absolute Dating ◽  
The Subject ◽  
Living Organisms

Modern geomorphology was founded in the nineteenth century as an exercise of historical interpretation of landscapes. After the mid-twentieth century it dominantly became a quest to understand the processes by which landscapes are modified. This focused attention on the measurement of sediment fluxes on synoptic timescales and on a reductionist, Newtonian programme of construction of low-order theories about those fluxes, largely imported from engineering science. The period also saw the emergence of an applied geomorphology. Toward the end of the twentieth century the subject was dramatically transformed by improved technologies for remote sensing and surveying of Earth’s surface, the advent of personal computation and of large-scale computation, and important developments of absolute dating techniques. These technical innovations in turn promoted recognition of geomorphology as a ‘system science’ and facilitated the reintegration of tectonics into geomorphology, opening the way for a renewed consideration of the history of the landscape. Finally, increasing recognition of the dominance of human agency in contemporary modification of Earth’s terrestrial surface has become a significant theme. Important influences on the continuing development of the subject will include the search for physically sound laws for material fluxes; reconciling geomorphological information and process representations across spatial and temporal scales, in both observation and theory; comprehending complexity in geomorphological processes and landform histories; incorporating the geomorphological role of living organisms, particularly micro-organisms; understanding the role of climate in geomorphology, both in the contemporary changing climate and in the long term; and fully admitting the now dominant role of humans as geomorphic agents. Geomorphology is simultaneously developing in diverse directions: on one hand, it is becoming a more rigorous geophysical science — a significant part of a larger earth science discipline; on another, it is becoming more concerned with human social and economic values, with environmental change, conservation ethics, with the human impact on environment, and with issues of social justice and equity.

Low Temperature Cu–Cu Bonding Technology in Three-Dimensional Integration: An Extensive Review

2018 ◽  
Vol 140 (1) ◽  
Author(s):  
Asisa Kumar Panigrahy ◽  
Kuan-Neng Chen
Keyword(s):  
Low Temperature ◽  
Integrated Circuit ◽  
Large Scale ◽  
Three Dimensional ◽  
3D Ic ◽  
Bonding Technology ◽  
Three Dimensional Integrated Circuit ◽  
Low Temperature Bonding ◽  
Cu Bonding

Arguably, the integrated circuit (IC) industry has received robust scientific and technological attention due to the ultra-small and extremely fast transistors since past four decades that consents to Moore's law. The introduction of new interconnect materials as well as innovative architectures has aided for large-scale miniaturization of devices, but their contributions were limited. Thus, the focus has shifted toward the development of new integration approaches that reduce the interconnect delays which has been achieved successfully by three-dimensional integrated circuit (3D IC). At this juncture, semiconductor industries utilize Cu–Cu bonding as a key technique for 3D IC integration. This review paper focuses on the key role of low temperature Cu–Cu bonding, renaissance of the low temperature bonding, and current research trends to achieve low temperature Cu–Cu bonding for 3D IC and heterogeneous integration applications.

Three-Dimensional Characterization of a Pure Thermal Plume

2005 ◽  
Vol 127 (6) ◽  
pp. 624-636 ◽  
Author(s):  
Minh Vuong Pham ◽  
Fre´de´ric Plourde ◽  
Son Doan Kim
Keyword(s):  
Direct Method ◽  
Three Dimensional ◽  
Momentum Equation ◽  
Thermal Plume ◽  
Thermal Plumes ◽  
Heating Source ◽  
Entrainment Coefficient ◽  
Particle Imaging ◽  
First Time

Pure thermal plumes have been investigated by two-dimensional (2D) and three-dimensional (3D) particle imaging velocimetry (PIV) techniques. While classical plume features have been checked out, time-dependent analysis allows one to clearly detect contraction and expulsion phases which are mainly driven by turbulent structure behavior. Balance of momentum equation demonstrates the link between stronger structures and expulsion-contraction motion mainly dominated by plume engulfment during contraction phases. A ratio of 3 between entrained mass flow rate during contraction and expulsion phases has been estimated. A new method, never previously applied to pure thermal plume, allows one to accurately characterize entrainment mechanism and for the first time, the latter renders it possible to estimate the entrainment coefficient all along the plume height, even close to the heating source. Moreover, entrainment coefficient is found to be 20% higher with direct method as opposed to the classical differential one widely used in the literature. Such a huge gap is found to be due to the fluctuating density and velocity part. Even through it markedly contributes to an enhanced entrainment mechanism, the role of fluctuation was generally overlooked in the previous works devoted to entrainment coefficient estimate.

Large-scale vertical motion and its influence on cloudiness

2020 ◽  
Author(s):  
Geet George ◽  
Bjorn Stevens ◽  
Sandrine Bony ◽  
Marcus Klingebiel
Keyword(s):  
Large Scale ◽  
Vertical Motion ◽  
Cumulus Clouds ◽  
Shallow Cumulus ◽  
Integrated Water Vapour ◽  
Thermodynamics And Dynamics ◽  
Lifting Condensation Level ◽  
The Impact ◽  
First Time

<p>This study uses measurements from the <em>Elucidating the Role of Clouds-Circulation Coupling in Climate</em>, EUREC<sup>4</sup>A and the second <em>Next-Generation Aircraft Remote Sensing for Validation</em>, NARVAL2 campaigns to investigate the influence of large-scale environmental conditions on cloudiness. For the first time, these campaigns provide divergence measurements, making it possible to explore the impact of large-scale vertical motions on clouds. We attempt to explain the cloudiness through the varying thermodynamics and dynamics in the different environments.  For most of the NARVAL2 case-studies, cloudiness is poorly related to thermodynamical factors such as sea-surface temperature and lower tropospheric stability. Factors such as integrated water vapour and pressure velocity (ω) at 500 hPa and 700 hPa can be used to distinguish between actively convecting and suppressed regions, but they are not useful in determining the variation in cloudiness among suppressed cases. We find that ω in the boundary layer (up to ∼2 km) has a more direct control on the low-level cloudiness in these regions, than that in the upper layers. We use a simplistic method to show that ω at the lifting condensation level can be used to determine the cloud cover of shallow cumulus clouds. Thus, we argue that cloud schemes in models should not rely only on thermodynamical information, but also on dynamical predictors.</p>

FEATURES OF PHOTOCONDUCTIVITY OF Ge AND Si WITH DISORDERED REGIONS

2010 ◽  
Vol 24 (31) ◽  
pp. 2985-2996 ◽  
Author(s):  
V. YEVSEYEV
Keyword(s):  
Large Scale ◽  
High Energy ◽  
Fast Neutrons ◽  
Potential Relief ◽  
Photoelectrical Properties ◽  
Recombination Centers ◽  
First Time ◽  
High Energy Particles ◽  
Disordered Regions

Influence of large radiation defects — disordered regions on photoconductivity of semiconductors Ge and Si , compensated as a result of an irradiation with fast neutrons and 1 GeV protons, is investigated. For the first time, the combined role of disordered regions and a large-scale potential relief in photoelectrical properties of Ge and Si , irradiated by high energy particles is defined. The model of photoconductivity that takes into consideration disordered regions as specific sensitizing recombination centers and allows formation of the spatial potential relief is developed.

scholarly journals Three-Dimensional Structures of the A, B, and CCapsids of Rhesus Monkey Rhadinovirus: Insights into GammaherpesvirusCapsid Assembly, Maturation, and DNAPackaging

2003 ◽  
Vol 77 (24) ◽  
pp. 13182-13193 ◽  
Author(s):  
Xue-Kui Yu ◽  
Christine M. O'Connor ◽  
Ivo Atanasov ◽  
Blossom Damania ◽  
Dean H. Kedes ◽  
...  
Keyword(s):  
Rhesus Monkey ◽  
Three Dimensional ◽  
Model System ◽  
Electron Cryomicroscopy ◽  
Interacting Protein ◽  
Structural Differences ◽  
Dimensional Reconstruction ◽  
Capsid Maturation ◽  
First Time

ABSTRACT Rhesus monkey rhadinovirus (RRV) exhibits high levels of sequence homology to human gammaherpesviruses, such as Kaposi's sarcoma-associated herpesvirus, and grows to high titers in cell cultures, making it a good model system for studying gammaherpesvirus capsid structure and assembly. We have purified RRV A, B, and C capsids, thus for the first time allowing direct structure comparisons by electron cryomicroscopy and three-dimensional reconstruction. The results show that the shells of these capsids are identical and are each composed of 12 pentons, 150 hexons, and 320 triplexes. Structural differences were apparent inside the shells and through the penton channels. The A capsid is empty, and its penton channels are open. The B capsid contains a scaffolding core, and its penton channels are closed. The C capsid contains a DNA genome, which is closely packaged into regularly spaced density shells (25Å apart), and its penton channels are open. The different statuses of the penton channels suggest a functional role of the channels during capsid maturation, and the overall structural similarities of RRV capsids to alphaherpesvirus capsids suggest a common assembly and maturation pathway. The RRV A capsid reconstruction at a 15-Å resolution, the best achieved for gammaherpesvirus particles, reveals overall structural similarities to alpha- and betaherpesvirus capsids. However, the outer regions of the capsid, including densities attributed to the Ta triplex and the small capsomer-interacting protein (SCIP or ORF65), exhibit prominent differences from their structural counterparts in alphaherpesviruses. This structural disparity suggests that SCIP and the triplex, together with tegument and envelope proteins, confer structural and potentially functional specificities to alpha-, beta-, and gammaherpesviruses.

scholarly journals Large-scale sequencing combined with bioinformatics analysis reveals KLF8 an apoptosis repressor in hepatocellular carcinoma

2019 ◽  
Author(s):  
Hao Xing ◽  
Jin Zhang ◽  
Kai-Lian Zheng ◽  
Ming-Da Wang ◽  
Jun Han ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Large Scale ◽  
Target Genes ◽  
Bioinformatics Analysis ◽  
Primary Liver Cancer ◽  
Panoramic View ◽  
Chip Sequencing ◽  
Apoptotic Effect ◽  
First Time

Abstract Backgrounds Hepatocellular carcinoma (HCC) is the most frequent primary liver cancer and the third leading cause of cancer death. Krüppel-like factor 8 (KLF8) is an oncogene and has been shown playing an important role in HCC, but the major involved signaling pathways are still unknown. Here, we systematically analyzed the role of KLF8 in HCC using RNA sequencing and the anti-H3K27 acetylation ChIP sequencing combined with bioinformatics analysis, and the results of data mining. Results The results in this study showed that KLF8 worked as a transcription repressor in HCC and the main directly regulated ones were apoptosis-related genes. Furthermore, we verified the combination of KLF8 with some predicted target genes by ChIP, which supported the effectiveness of our analysis. Besides, we demonstrated that HMGA2 and MMP7, two predicted targets, were important participants in KLF8 mediated anti-apoptotic effect in HCC. Conclusions Our work offers a panoramic view of KLF8’s role in HCC for the first time and facilitates the discovery of new targets for HCC via KLF8.

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