scholarly journals The emergence of heterogeneous scaling in research institutions

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Keith A. Burghardt ◽  
Zihao He ◽  
Allon G. Percus ◽  
Kristina Lerman
Keyword(s):  
Simple Model ◽  
Power Law ◽  
Scientific Discovery ◽  
Emergent Behavior ◽  
Research Institutions ◽  
Zipf's Law ◽  
Production Of Knowledge ◽  
Economy Of Scale ◽  
Scientific Papers ◽  
New Institutions

AbstractResearch institutions provide the infrastructure for scientific discovery, yet their role in the production of knowledge is not well characterized. To address this gap, we analyze interactions of researchers within and between institutions from millions of scientific papers. Our analysis reveals that collaborations densify as each institution grows, but at different rates (heterogeneous densification). We also find that the number of institutions scales with the number of researchers as a power law (Heaps’ law) and institution sizes approximate Zipf’s law. These patterns can be reproduced by a simple model in which researchers are preferentially hired by large institutions, while new institutions complimentarily generate more new institutions. Finally, new researchers form triadic closures with collaborators. This model reveals an economy of scale in research: larger institutions grow faster and amplify collaborations. Our work deepens the understanding of emergent behavior in research institutions and their role in facilitating collaborations.

scholarly journals The structure of co-publications multilayer network

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ghislain Romaric Meleu ◽  
Paulin Yonta Melatagia
Keyword(s):  
Power Law ◽  
Degree Distribution ◽  
Preferential Attachment ◽  
Small World ◽  
Generation Model ◽  
Small World Network ◽  
Power Law Distribution ◽  
Multilayer Networks ◽  
Multilayer Network ◽  
Scientific Papers

AbstractUsing the headers of scientific papers, we have built multilayer networks of entities involved in research namely: authors, laboratories, and institutions. We have analyzed some properties of such networks built from data extracted from the HAL archives and found that the network at each layer is a small-world network with power law distribution. In order to simulate such co-publication network, we propose a multilayer network generation model based on the formation of cliques at each layer and the affiliation of each new node to the higher layers. The clique is built from new and existing nodes selected using preferential attachment. We also show that, the degree distribution of generated layers follows a power law. From the simulations of our model, we show that the generated multilayer networks reproduce the studied properties of co-publication networks.

scholarly journals ZIPF'S LAW AND RANDOM TEXTS

2002 ◽  
Vol 05 (01) ◽  
pp. 1-6 ◽  
Author(s):  
RAMON FERRER i CANCHO ◽  
RICARD V. SOLÉ
Keyword(s):  
Word Frequency ◽  
Power Law ◽  
Word Length ◽  
A Priori ◽  
Zipf’S Law ◽  
Strict Sense ◽  
A Priori Information ◽  
Zipf's Law ◽  
Priori Information ◽  
Random Text

Random-text models have been proposed as an explanation for the power law relationship between word frequency and rank, the so-called Zipf's law. They are generally regarded as null hypotheses rather than models in the strict sense. In this context, recent theories of language emergence and evolution assume this law as a priori information with no need of explanation. Here, random texts and real texts are compared through (a) the so-called lexical spectrum and (b) the distribution of words having the same length. It is shown that real texts fill the lexical spectrum much more efficiently and regardless of the word length, suggesting that the meaningfulness of Zipf's law is high.

scholarly journals Simple model for the power-law blinking of single semiconductor nanocrystals

2002 ◽  
Vol 66 (23) ◽  
Author(s):  
Rogier Verberk ◽  
Antoine M. van Oijen ◽  
Michel Orrit
Keyword(s):  
Simple Model ◽  
Power Law ◽  
Semiconductor Nanocrystals

The time to failure of fiber bundles subjected to random loads

1979 ◽  
Vol 11 (03) ◽  
pp. 527-541 ◽  
Author(s):  
Howard M. Taylor
Keyword(s):  
Simple Model ◽  
Power Law ◽  
Failure Time ◽  
Constant Load ◽  
Asymptotic Distributions ◽  
Asymptotic Independence ◽  
Time To Failure ◽  
Random Load ◽  
The Mean ◽  
Wave Induced

The effect on cable reliability of random cyclic loading such as that generated by the wave-induced rocking of ocean vessels deploying these cables is examined. A simple model yielding exact formulas is first explored. In this model, the failure time of a single fiber under a constant load is assumed to be exponentially distributed, and the random loadings are a two-state stationary Markov process. The effect of load on failure time is assumed to follow a power law breakdown rule. In this setting, exact results concerning the distribution of bundle or cable failure time, and especially the mean failure time, are obtained. Where the fluctuations in load are frequent relative to bundle life, such as may occur in long-lived cables, it is shown that randomness in load tends to decrease mean bundle life, but it is suggested that the reduction in mean life often can be restored by modestly reducing the base load on the structure or by modestly increasing the number of elements in the bundle. In later pages this simple model is extended to cover a broader range of materials and random loadings. Asymptotic distributions and mean failure times are given where fibers follow a Weibull distribution of failure time under constant load, and loads that are general non-negative stationary processes subject only to some mild condition of asymptotic independence. When the power law breakdown exponent is large, the mean time to bundle failure depends heavily on the exact form of the marginal probability distribution for the random load process and cannot be summarized by the first two moments of this distribution alone.

scholarly journals (A)Historical Science

2015 ◽  
Vol 83 (12) ◽  
pp. 4460-4464 ◽  
Author(s):  
Arturo Casadevall ◽  
Ferric C. Fang
Keyword(s):  
History Of Science ◽  
Scientific Discovery ◽  
Academic Disciplines ◽  
Ethical Standards ◽  
Actual Process ◽  
Historical Science ◽  
Scientific Process ◽  
Science History ◽  
Scientific Papers ◽  
History Of

In contrast to many other human endeavors, science pays little attention to its history. Fundamental scientific discoveries are often considered to be timeless and independent of how they were made. Science and the history of science are regarded as independent academic disciplines. Although most scientists are aware of great discoveries in their fields and their association with the names of individual scientists, few know the detailed stories behind the discoveries. Indeed, the history of scientific discovery is sometimes recorded only in informal accounts that may be inaccurate or biased for self-serving reasons. Scientific papers are generally written in a formulaic style that bears no relationship to the actual process of discovery. Here we examine why scientists should care more about the history of science. A better understanding of history can illuminate social influences on the scientific process, allow scientists to learn from previous errors, and provide a greater appreciation for the importance of serendipity in scientific discovery. Moreover, history can help to assign credit where it is due and call attention to evolving ethical standards in science. History can make science better.

scholarly journals The Diversity of Broad Emission-Line Profiles

1997 ◽  
Vol 159 ◽  
pp. 197-198
Author(s):  
Giovanna M. Stirpe ◽  
Andrew Robinson ◽  
David J. Axon
Keyword(s):  
Simple Model ◽  
Emission Line ◽  
Power Law ◽  
Active Galaxies ◽  
Broad Line ◽  
Line Profiles ◽  
Broad Emission ◽  
Power Law Function ◽  
Broad Emission Line ◽  
Almost All

AbstractWe present preliminary results from a study of broad-line profiles in active galaxies. A simple model in which the emissivity is a broken power-law function of radius, and the BLR clouds emit anisotropically, yields very good fits to almost all the Ha profiles in our data base.

The Natural History Society of New Brunswick Library: Supporting Geological Science

2010 ◽  
Vol 29 (1) ◽  
pp. 146-170 ◽  
Author(s):  
Diane Buhay ◽  
Randall Miller
Keyword(s):  
Public Education ◽  
Natural History ◽  
New Brunswick ◽  
Scientific Discovery ◽  
Leading Edge ◽  
Technical Literature ◽  
Natural History Society ◽  
Research Activities ◽  
Scientific Papers ◽  
The City

The Natural History Society of New Brunswick (1862-1932) based in Saint John, New Brunswick, Canada, produced an impressive body of research, including significant geological discoveries. Research and public education output of the Society was prolific. George Matthew, the Society's leading geologist published more than 200 scientific papers. Between 1862 and 1917 the Bulletin of the Natural History Society of New Brunswick records more than 800 lectures read before the Society and public audiences. Lectures were often at the leading edge of scientific discovery, such as Matthew's 1890 report of the first authentic Precambrian fossil. This amateur society supported the research of its members by developing a significant library. The only other library in the city with scientific resources belonged to the local Mechanics' Institute, later acquired in part by the Natural History Society. It is clear from library reports and minutes that, from the beginning, the intent was to provide members access to a science library necessary to support their research activities. Both libraries were particularly important as the Great Fire of 1877 destroyed personal libraries while the Society and Institute libraries were untouched. The library was particularly strong in North American and British journals and classic works in early geology. Some of the research shortcomings of Society members may have been a result of the library's weakness in European technical literature. The library and collections of the Natural History Society of New Brunswick formed the basis for the present New Brunswick Museum.

Extending the Theory of Creep to Viscoplasticity

1994 ◽  
Vol 116 (1) ◽  
pp. 67-75 ◽  
Author(s):  
A. D. Freed ◽  
K. P. Walker ◽  
M. J. Verrilli
Keyword(s):  
Steady State ◽  
Simple Model ◽  
Power Law ◽  
Copper Alloy ◽  
Theoretical Framework ◽  
Kinetics Equation ◽  
Creep Theory ◽  
Material Functions

A viscoplastic theory is developed that reduces to creep theory analytically under steady-state conditions. A fairly simple model is constructed from this theoretical framework by defining material functions that have close ties to the physics of inelasticity; consequently, the model is characterized easily. The computational characteristics of the model are enhanced, in general, by converting the kinetics equation from a hyperbolic relationship to a power-law relationship. The resulting model is applied to copper and to the copper alloy, NARloy Z.

THE RELATION OF JET QUENCHING AND POWER-LAW OBSERVED IN pT-DISTRIBUTIONS IN RELATIVISTIC HEAVY-ION COLLISIONS

2006 ◽  
Vol 15 (04) ◽  
pp. 865-876
Author(s):  
WANG LI ◽  
XIAO DONG WANG
Keyword(s):  
Simple Model ◽  
Power Law ◽  
Recent Observation ◽  
Fractal Dimensions ◽  
Heavy Ion ◽  
High Energy ◽  
Jet Quenching ◽  
Relativistic Heavy Ion Collisions ◽  
Distribution Data ◽  
Ion Collisions

Recent observation of high-pT hadron spectra suppression and mono-jet production in central Au-Au collisions and Cu-Cu collisions at RHIC have confirmed the long predicted phenomenon of jet quenching in high-energy-ion collisions. Detailed analyses of the experimental data show parton energy loss as the mechanism for the discovered jet quenching. Preconception-free analyses of the inclusive invariant transverse-momentum distribution data taken from the measurements of Au-Au collisions at [Formula: see text] and [Formula: see text] have been performed. It is observed that the distribution exhibits for pT≥2 GeV/c remarkably good power-law behavior (pT-scaling) with general regularities. It may explain the data coming from the STAR or PHENIX to some extent. Using the power-law by a simple model, its underlying geometrical structure has to be understood in terms of fractal dimensions. A simple model is proposed which approximately reproduces the above-mentioned data for the phenomenon, and it affords a new way to research the QGP matter and jet quenching. Further heavy-ion collision experiments are suggested.

The time to failure of fiber bundles subjected to random loads

1979 ◽  
Vol 11 (3) ◽  
pp. 527-541 ◽  
Author(s):  
Howard M. Taylor
Keyword(s):  
Simple Model ◽  
Power Law ◽  
Failure Time ◽  
Constant Load ◽  
Asymptotic Distributions ◽  
Asymptotic Independence ◽  
Time To Failure ◽  
Random Load ◽  
The Mean ◽  
Wave Induced

The effect on cable reliability of random cyclic loading such as that generated by the wave-induced rocking of ocean vessels deploying these cables is examined. A simple model yielding exact formulas is first explored. In this model, the failure time of a single fiber under a constant load is assumed to be exponentially distributed, and the random loadings are a two-state stationary Markov process. The effect of load on failure time is assumed to follow a power law breakdown rule. In this setting, exact results concerning the distribution of bundle or cable failure time, and especially the mean failure time, are obtained. Where the fluctuations in load are frequent relative to bundle life, such as may occur in long-lived cables, it is shown that randomness in load tends to decrease mean bundle life, but it is suggested that the reduction in mean life often can be restored by modestly reducing the base load on the structure or by modestly increasing the number of elements in the bundle.In later pages this simple model is extended to cover a broader range of materials and random loadings. Asymptotic distributions and mean failure times are given where fibers follow a Weibull distribution of failure time under constant load, and loads that are general non-negative stationary processes subject only to some mild condition of asymptotic independence. When the power law breakdown exponent is large, the mean time to bundle failure depends heavily on the exact form of the marginal probability distribution for the random load process and cannot be summarized by the first two moments of this distribution alone.

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