Pub Date : 2017-01-01DOI: 10.4249/scholarpedia.32144
Vassilis Cutsuridis, A. Moustafa
There have been a few attempts to design computational models of AD. Some of these models focus on hippocampus function yet many suffer from simulating exact effects of amyloid plaques and neurofibrillary tangles. See Duch (2007) for a review of some AD models. Below, we discuss biochemical, single cell, biophysical spiking, and systems-level and abstract models of AD.
{"title":"Computational models of Alzheimer's disease","authors":"Vassilis Cutsuridis, A. Moustafa","doi":"10.4249/scholarpedia.32144","DOIUrl":"https://doi.org/10.4249/scholarpedia.32144","url":null,"abstract":"There have been a few attempts to design computational models of AD. Some of these models focus on hippocampus function yet many suffer from simulating exact effects of amyloid plaques and neurofibrillary tangles. See Duch (2007) for a review of some AD models. Below, we discuss biochemical, single cell, biophysical spiking, and systems-level and abstract models of AD.","PeriodicalId":74760,"journal":{"name":"Scholarpedia journal","volume":"12 1","pages":"32144"},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70978431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-12-20DOI: 10.4249/scholarpedia.32440
Matthias Bartelmann, Matteo Maturi
According to the theory of general relativity, masses deflect light in a way similar to convex glass lenses. This gravitational lensing effect is astigmatic, giving rise to image distortions. These distortions allow to quantify cosmic structures statistically on a broad range of scales, and to map the spatial distribution of dark and visible matter. We summarise the theory of weak gravitational lensing and review applications to galaxies, galaxy clusters and larger-scale structures in the Universe.
{"title":"Weak gravitational lensing","authors":"Matthias Bartelmann, Matteo Maturi","doi":"10.4249/scholarpedia.32440","DOIUrl":"https://doi.org/10.4249/scholarpedia.32440","url":null,"abstract":"According to the theory of general relativity, masses deflect light in a way similar to convex glass lenses. This gravitational lensing effect is astigmatic, giving rise to image distortions. These distortions allow to quantify cosmic structures statistically on a broad range of scales, and to map the spatial distribution of dark and visible matter. We summarise the theory of weak gravitational lensing and review applications to galaxies, galaxy clusters and larger-scale structures in the Universe.","PeriodicalId":74760,"journal":{"name":"Scholarpedia journal","volume":"12 1","pages":"32440"},"PeriodicalIF":0.0,"publicationDate":"2016-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70979167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-11-19DOI: 10.4249/scholarpedia.12389
G. Loeb, R. Davoodi
A large part of our central nervous system is dedicated to control of movement. To gain a fuller understanding of the sensorimotor control of movement, we must study both the central nervous system and the musculoskeletal system that it controls. A control engineer would never design a control system before fully understanding the characteristics of the controlled plant. Similarly, the biological motor control system cannot be understood fully by studying the control circuits while ignoring the inherent properties of the musculoskeletal system that it must control. Models that capture the mechanical dynamics of the musculoskeletal system, especially when they are combined with the models of the control circuits in the central nervous system, allow us to study the control of movement in its entirety.
{"title":"Musculoskeletal Mechanics and Modeling","authors":"G. Loeb, R. Davoodi","doi":"10.4249/scholarpedia.12389","DOIUrl":"https://doi.org/10.4249/scholarpedia.12389","url":null,"abstract":"A large part of our central nervous system is dedicated to control of movement. To gain a fuller understanding of the sensorimotor control of movement, we must study both the central nervous system and the musculoskeletal system that it controls. A control engineer would never design a control system before fully understanding the characteristics of the controlled plant. Similarly, the biological motor control system cannot be understood fully by studying the control circuits while ignoring the inherent properties of the musculoskeletal system that it must control. Models that capture the mechanical dynamics of the musculoskeletal system, especially when they are combined with the models of the control circuits in the central nervous system, allow us to study the control of movement in its entirety.","PeriodicalId":74760,"journal":{"name":"Scholarpedia journal","volume":"11 1","pages":"12389"},"PeriodicalIF":0.0,"publicationDate":"2016-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70964733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-09-06DOI: 10.4249/scholarpedia.33528
Thomas Mädler, J. Winicour
The Bondi-Sachs formalism of General Relativity is a metric-based treatment of the Einstein equations in which the coordinates are adapted to the null geodesics of the spacetime. It provided the first convincing evidence that gravitational radiation is a nonlinear effect of general relativity and that the emission of gravitational waves from an isolated system is accompanied by a mass loss from the system. The asymptotic behaviour of the Bondi-Sachs metric revealed the existence of the symmetry group at null infinity, the Bondi-Metzner-Sachs group, which turned out to be larger than the Poincare group.
{"title":"Bondi-Sachs Formalism","authors":"Thomas Mädler, J. Winicour","doi":"10.4249/scholarpedia.33528","DOIUrl":"https://doi.org/10.4249/scholarpedia.33528","url":null,"abstract":"The Bondi-Sachs formalism of General Relativity is a metric-based treatment of the Einstein equations in which the coordinates are adapted to the null geodesics of the spacetime. It provided the first convincing evidence that gravitational radiation is a nonlinear effect of general relativity and that the emission of gravitational waves from an isolated system is accompanied by a mass loss from the system. The asymptotic behaviour of the Bondi-Sachs metric revealed the existence of the symmetry group at null infinity, the Bondi-Metzner-Sachs group, which turned out to be larger than the Poincare group.","PeriodicalId":74760,"journal":{"name":"Scholarpedia journal","volume":"17 1","pages":"33528"},"PeriodicalIF":0.0,"publicationDate":"2016-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70980198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-07-22DOI: 10.4249/scholarpedia.32454
Lu Lu, A. Watson
New observations with ESO’s Very Large Telescope (VLT) in Chile have revealed alignments over the largest structures ever discovered in the Universe. A European research team has found that the rotation axes of the central supermassive black holes in a sample of quasars are parallel to each other over distances of billions of light-years. The team has also found that the rotation axes of these quasars tend to be aligned with the vast structures in the cosmic web in which they reside. [6]
{"title":"High energy cosmic rays","authors":"Lu Lu, A. Watson","doi":"10.4249/scholarpedia.32454","DOIUrl":"https://doi.org/10.4249/scholarpedia.32454","url":null,"abstract":"New observations with ESO’s Very Large Telescope (VLT) in Chile have revealed alignments over the largest structures ever discovered in the Universe. A European research team has found that the rotation axes of the central supermassive black holes in a sample of quasars are parallel to each other over distances of billions of light-years. The team has also found that the rotation axes of these quasars tend to be aligned with the vast structures in the cosmic web in which they reside. [6]","PeriodicalId":74760,"journal":{"name":"Scholarpedia journal","volume":"11 1","pages":"32454"},"PeriodicalIF":0.0,"publicationDate":"2016-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70979392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-06-03DOI: 10.4249/scholarpedia.32643
P. Koppenburg, Zdenek Dolezal, M. Smizanska
Rare decays of b hadrons provide a powerful way of identifying contributions from physics beyond the Standard Model, in particular from new hypothetical particles too heavy to be produced at colliders. The most relevant experimental measurements are reviewed and possible interpretations are briefly discussed.
{"title":"Rare decays of b hadrons","authors":"P. Koppenburg, Zdenek Dolezal, M. Smizanska","doi":"10.4249/scholarpedia.32643","DOIUrl":"https://doi.org/10.4249/scholarpedia.32643","url":null,"abstract":"Rare decays of b hadrons provide a powerful way of identifying contributions from physics beyond the Standard Model, in particular from new hypothetical particles too heavy to be produced at colliders. The most relevant experimental measurements are reviewed and possible interpretations are briefly discussed.","PeriodicalId":74760,"journal":{"name":"Scholarpedia journal","volume":"11 1","pages":"32643"},"PeriodicalIF":0.0,"publicationDate":"2016-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70979469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-01-10DOI: 10.4249/scholarpedia.30946
R. Jalabert
The field of Quantum Chaos, addressing the quantum manifestations of an underlying classically chaotic dynamics, was developed in the early eighties, mainly from a theoretical perspective. Few experimental systems were initially recognized to exhibit the versatility of being sensitive, at the same time, to their classical and quantum dynamics. Rydberg atoms provided the main testing ground of Quantum Chaos concepts until the early nineties, marked by the development of microwave billiards, ultra-cold atoms in optical lattices, and low-temperature transport in mesoscopic semiconductor structures. The mesoscopic regime is attained in small condensed matter systems at sufficiently low temperatures for the electrons to propagate coherently across the sample. The quantum coherence of electrons, together with the ballistic motion characteristic of ultra-clean microstructures, motivated the proposal of mesocopic systems as a very special laboratory for performing measurements and testing the theoretical ideas of Quantum Chaos. Experimental realizations and many important developments, reviewed in this article, followed from such a connection.
{"title":"Mesoscopic transport and quantum chaos","authors":"R. Jalabert","doi":"10.4249/scholarpedia.30946","DOIUrl":"https://doi.org/10.4249/scholarpedia.30946","url":null,"abstract":"The field of Quantum Chaos, addressing the quantum manifestations of an underlying classically chaotic dynamics, was developed in the early eighties, mainly from a theoretical perspective. Few experimental systems were initially recognized to exhibit the versatility of being sensitive, at the same time, to their classical and quantum dynamics. Rydberg atoms provided the main testing ground of Quantum Chaos concepts until the early nineties, marked by the development of microwave billiards, ultra-cold atoms in optical lattices, and low-temperature transport in mesoscopic semiconductor structures. The mesoscopic regime is attained in small condensed matter systems at sufficiently low temperatures for the electrons to propagate coherently across the sample. The quantum coherence of electrons, together with the ballistic motion characteristic of ultra-clean microstructures, motivated the proposal of mesocopic systems as a very special laboratory for performing measurements and testing the theoretical ideas of Quantum Chaos. Experimental realizations and many important developments, reviewed in this article, followed from such a connection.","PeriodicalId":74760,"journal":{"name":"Scholarpedia journal","volume":"11 1","pages":"30946"},"PeriodicalIF":0.0,"publicationDate":"2016-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70976601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-01-01DOI: 10.4249/scholarpedia.33333
Fernando Silva, L. Correia, A. Christensen
{"title":"Evolutionary Robotics","authors":"Fernando Silva, L. Correia, A. Christensen","doi":"10.4249/scholarpedia.33333","DOIUrl":"https://doi.org/10.4249/scholarpedia.33333","url":null,"abstract":"","PeriodicalId":74760,"journal":{"name":"Scholarpedia journal","volume":"11 1","pages":"33333"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70980422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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