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Institution

University of California, Santa Barbara

EducationSanta Barbara, California, United States
About: University of California, Santa Barbara is a education organization based out in Santa Barbara, California, United States. It is known for research contribution in the topics: Population & Galaxy. The organization has 30281 authors who have published 80852 publications receiving 4626827 citations. The organization is also known as: UC Santa Barbara & UCSB.
Topics: Population, Galaxy, Laser, Quantum well, Quantum dot


Papers
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Journal ArticleDOI
TL;DR: These complex relationships between phenotypic differences and the dynamics of competing species argue against the simple use of single functional traits to infer community assembly processes but lay the groundwork for a theoretically justified trait-based community ecology.
Abstract: Understanding the processes maintaining species diversity is a central problem in ecology, with implications for the conservation and management of ecosystems. Although biologists often assume that trait differences between competitors promote diversity, empirical evidence connecting functional traits to the niche differences that stabilize species coexistence is rare. Obtaining such evidence is critical because traits also underlie the average fitness differences driving competitive exclusion, and this complicates efforts to infer community dynamics from phenotypic patterns. We coupled field-parameterized mathematical models of competition between 102 pairs of annual plants with detailed sampling of leaf, seed, root, and whole-plant functional traits to relate phenotypic differences to stabilizing niche and average fitness differences. Single functional traits were often well correlated with average fitness differences between species, indicating that competitive dominance was associated with late phenology, deep rooting, and several other traits. In contrast, single functional traits were poorly correlated with the stabilizing niche differences that promote coexistence. Niche differences could only be described by combinations of traits, corresponding to differentiation between species in multiple ecological dimensions. In addition, several traits were associated with both fitness differences and stabilizing niche differences. These complex relationships between phenotypic differences and the dynamics of competing species argue against the simple use of single functional traits to infer community assembly processes but lay the groundwork for a theoretically justified trait-based community ecology.

656 citations

Journal ArticleDOI
TL;DR: The hypothesis that chronic energy stress is the primary selective pressure governing the evolution of the Archaea is proposed and proposed, and biochemical mechanisms that enable archaea to cope with chronicEnergy stress include low-permeability membranes and specific catabolic pathways.
Abstract: The three domains of life on Earth include the two prokaryotic groups, Archaea and Bacteria. The Archaea are distinguished from Bacteriabased on phylogenetic and biochemical differences, but currently there is no unifying ecological principle to differentiate these groups. The ecology of the Archaea is reviewed here in terms of cellular bioenergetics. Adaptation to chronic energy stress is hypothesized to be the crucial factor that distinguishes the Archaea from Bacteria. The biochemical mechanisms that enable archaea to cope with chronic energy stress include low-permeability membranes and specific catabolic pathways. Based on the ecological unity and biochemical adaptations among archaea, I propose the hypothesis that chronic energy stress is the primary selective pressure governing the evolution of the Archaea.

656 citations

Journal ArticleDOI
TL;DR: In this article, the authors discuss the theoretical prediction, experimental realization, and potential use of Majorana zero modes in future information processing devices through braiding-based topological quantum computation.
Abstract: We provide a current perspective on the rapidly developing field of Majorana zero modes in solid state systems. We emphasize the theoretical prediction, experimental realization, and potential use of Majorana zero modes in future information processing devices through braiding-based topological quantum computation. Well-separated Majorana zero modes should manifest non-Abelian braiding statistics suitable for unitary gate operations for topological quantum computation. Recent experimental work, following earlier theoretical predictions, has shown specific signatures consistent with the existence of Majorana modes localized at the ends of semiconductor nanowires in the presence of superconducting proximity effect. We discuss the experimental findings and their theoretical analyses, and provide a perspective on the extent to which the observations indicate the existence of anyonic Majorana zero modes in solid state systems. We also discuss fractional quantum Hall systems (the 5/2 state) in this context. We describe proposed schemes for carrying out braiding with Majorana zero modes as well as the necessary steps for implementing topological quantum computation.

655 citations

Journal ArticleDOI
TL;DR: This work extends the Koopman operator to controlled dynamical systems and applies the Extended Dynamic Mode Decomposition (EDMD) to compute a finite-dimensional approximation of the operator in such a way that this approximation has the form of a linearcontrolled dynamical system.

655 citations

Journal ArticleDOI
TL;DR: The authors showed that a continuum of ages exists within each starting class due to the use of a single school cut-off date, making the older children approximately twenty percent older than the younger children at school entry.
Abstract: A continuum of ages exists within each starting class due to the use of a single school cut-off date – making the “oldest” children approximately twenty percent older than the “youngest” children at school entry. We provide substantial evidence that these initial maturity differences have long lasting effects on student performance across OECD countries. In particular, the youngest members of each cohort score 4-12 percentiles lower than the oldest members in grade four, and 2-9 percentiles lower in grade eight, depending upon the country. In fact, data from Canada and the United States shows that the youngest members of a cohort are even less likely to enroll in pre-university academic track courses and high-end academic universities. Taken together, these findings point to important early relative maturity effects that propagate themselves into adulthood through the structure of education systems.

655 citations


Authors

Showing all 30652 results

NameH-indexPapersCitations
George M. Whitesides2401739269833
Yi Chen2174342293080
Simon D. M. White189795231645
George Efstathiou187637156228
Peidong Yang183562144351
David R. Williams1782034138789
Alan J. Heeger171913147492
Richard H. Friend1691182140032
Jiawei Han1681233143427
Gang Chen1673372149819
Alexander S. Szalay166936145745
Omar M. Yaghi165459163918
Carlos S. Frenk165799140345
Yang Yang1642704144071
Carlos Bustamante161770106053
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20241
2023150
2022528
20213,351
20203,653
20193,516