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Institution

University of Texas at Austin

EducationAustin, Texas, United States
About: University of Texas at Austin is a education organization based out in Austin, Texas, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 94352 authors who have published 206297 publications receiving 9070052 citations. The organization is also known as: UT-Austin & UT Austin.


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Journal ArticleDOI
TL;DR: A development of culture media and methods which has led to description of the salient growth characteristics of three blue-green algae: Anabaena variabilis, Anacystis nidulans, and Nostoc muscorum G are presented.
Abstract: LITTLE ATTENTION has been given to the more general features of the physiology of the blue-green algae. Specific attention has been given to nitrogen fixation (e.g., Allison et al., 1937; Burris and Wilson, 1946; Fogg, 1947) and limited aspects of photosynthesis (e.g., Emerson and Lewis, 1942; Frenkel et al., 1950; Duysens, 1952; Brown and Webster, 1953). Nutritional requirements have been investigated, notably by Fogg (1949), Gerloff et al. (1950, 1952) and Allen (1952). However, no study has been carried to the point of developing a blue-green alga as a reliable tool organism for physiological studies. There have been two obstacles to such development. One may be attributed to the difficulties of isolation and the lack of species in pure culture which suspend readily and submit to simplicity of manipulation possible with green algae such as Chlorella and Scenedesmus. A second difficulty arises from inadequate provision of carbon dioxide inherent in most of the culture methods used. Nutritional requirements have been defined in terms of the maximum growth yield obtained in cultures in cotton-stoppered flasks. Methods have not been developed for routine study of growth rate, a characteristic far more useful and interpretable for physiological work. The' present paper presents a development of culture media and methods which has led to description of the salient growth characteristics of three blue-green algae: Anabaena variabilis, Anacystis nidulans, and Nostoc muscorum G. Fragmentary data on three other blue-green algae are included. MATERIALS AND METHODS.-Because of the uncertainties of taxonomy of the simpler algae the species used will be described in terms of their history. 1. Anabaena variabilis (Kiitzing). Filamentous, but filaments very short in turbulent culture; isolated by and obtained from R. C. Hecker as Cylindrospermum sp. (1950); revised identification by E. G. Pringsheim. 2. Anacystis nidulans. Twoto four-cell filaments, but unicellular in turbulent culture; established as a unicellular culture by one of us (WK) and purified by M. B. Allen, tentative identification by F. Drouet; original description not found. 3. Nostoc muscorum G (Kiitzing). Filamentous, but filaments short in turbulent culture; obtained from G. C. Gerloff. 4. Nostoc muscorum A (Kiitzing). Filamentous, forming clumps even in turbulent culture; isolated by and obtained from F. E. Allison. 5. Anabaena cylindrica (Lemmerman) . Fila-

1,079 citations

Journal ArticleDOI
TL;DR: The negative abnormal capital investment/return relation is stronger for firms that have greater investment discretion, i.e., firms with higher cash flows and lower debt ratios, and is significant only in time periods when hostile takeovers were less prevalent as mentioned in this paper.
Abstract: Firms that substantially increase capital investments subsequently achieve negative benchmark-adjusted returns. The negative abnormal capital investment/return relation is shown to be stronger for firms that have greater investment discretion, i.e., firms with higher cash flows and lower debt ratios, and is shown to be significant only in time periods when hostile takeovers were less prevalent. These observations are consistent with the hypothesis that investors tend to underreact to the empire building implications of increased investment expenditures. Although firms that increase capital investments tend to have high past returns and often issue equity, the negative abnormal capital investment/return relation is independent of the previously documented long-term return reversal and secondary equity issue anomalies.

1,078 citations

Book ChapterDOI
TL;DR: How to run the open-source breseq computational pipeline to identify and annotate genetic differences found in whole-genome and whole-population NGS data from haploid microbes where a high-quality reference genome is available is described.
Abstract: Next-generation DNA sequencing (NGS) can be used to reconstruct eco-evolutionary population dynamics and to identify the genetic basis of adaptation in laboratory evolution experiments. Here, we describe how to run the open-source breseq computational pipeline to identify and annotate genetic differences found in whole-genome and whole-population NGS data from haploid microbes where a high-quality reference genome is available. These methods can also be used to analyze mutants isolated in genetic screens and to detect unintended mutations that may occur during strain construction and genome editing.

1,077 citations

Journal ArticleDOI
TL;DR: In this paper, a wealth of information obtained from quasistationary laboratory experiments for plasma confinement is reviewed for drift waves driven unstable by density gradients, temperature gradients and trapped particle effects.
Abstract: Drift waves occur universally in magnetized plasmas producing the dominant mechanism for the transport of particles, energy and momentum across magnetic field lines. A wealth of information obtained from quasistationary laboratory experiments for plasma confinement is reviewed for drift waves driven unstable by density gradients, temperature gradients and trapped particle effects. The modern understanding of Bohm transport and the role of sheared flows and magnetic shear in reducing the transport to the gyro-Bohm rate are explained and illustrated with large scale computer simulations. The types of mixed wave and vortex turbulence spontaneously generated in nonuniform plasmas are derived with reduced magnetized fluid descriptions. The types of theoretical descriptions reviewed include weak turbulence theory, Kolmogorov anisotropic spectral indices, and the mixing length. A number of standard turbulent diffusivity formulas are given for the various space-time scales of the drift-wave turbulent mixing.

1,076 citations

Journal ArticleDOI
TL;DR: In this paper, a flow visualization and spectral studies of flow between concentric independently rotating cylinders have revealed a surprisingly large variety of different flow states, including Taylor vortices, wavy vortice, modulated wavy vectors, outflow boundaries and internal waves.
Abstract: Our flow-visualization and spectral studies of flow between concentric independently rotating cylinders have revealed a surprisingly large variety of different flow states. (The system studied has radius ratio 0.883, aspect ratios ranging from 20 to 48, and the end boundaries were attached to the outer cylinder.) Different states were distinguished by their symmetry under rotation and reflection, by their azimuthal and axial wavenumbers, and by the rotation frequencies of the azimuthal travelling waves. Transitions between states were determined as functions of the inner- and outer-cylinder Reynolds numbers, Ri and Ro, respectively. The transitions were located by fixing Ro and slowly increasing Ri. Observed states include Taylor vortices, wavy vortices, modulated wavy vortices, vortices with wavy outflow boundaries, vortices with wavy inflow boundaries, vortices with flat boundaries and internal waves (twists), laminar spirals, interpenetrating spirals, waves on interpenetrating spirals, spiral turbulence, a flow with intermittent turbulent spots, turbulent Taylor vortices, a turbulent flow with no large-scale features, and various combinations of these flows. Some of these flow states have not been previously described, and even for those states that were previously described the present work provides the first coherent characterization of the states and the transitions between them. These flow states are all stable to small perturbations, and the transition boundaries between the states are reproducible. These observations can serve as a challenge and test for future analytic and numerical studies, and the map of the transitions provides several possible codimension-2 bifurcations that warrant further study.

1,076 citations


Authors

Showing all 95138 results

NameH-indexPapersCitations
George M. Whitesides2401739269833
Eugene Braunwald2301711264576
Yi Chen2174342293080
Robert J. Lefkowitz214860147995
Joseph L. Goldstein207556149527
Eric N. Olson206814144586
Hagop M. Kantarjian2043708210208
Rakesh K. Jain2001467177727
Francis S. Collins196743250787
Gordon B. Mills1871273186451
Scott M. Grundy187841231821
Michael S. Brown185422123723
Eric Boerwinkle1831321170971
Aaron R. Folsom1811118134044
Jiaguo Yu178730113300
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
2023304
20221,209
202110,137
202010,331
20199,727
20188,973