Temperature Dependence of the Optical Spectral Weight in the Cuprates: Role of Electron Correlations

2005 ◽  
Vol 95 (9) ◽  
Author(s):  
A. Toschi ◽  
M. Capone ◽  
M. Ortolani ◽  
P. Calvani ◽  
S. Lupi ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Spectral Weight ◽  
Electron Correlations

scholarly journals Role of carbon allocation efficiency in the temperature dependence of autotroph growth rates

2018 ◽  
Vol 115 (31) ◽  
pp. E7361-E7368 ◽  
Author(s):  
Bernardo García-Carreras ◽  
Sofía Sal ◽  
Daniel Padfield ◽  
Dimitrios-Georgios Kontopoulos ◽  
Elvire Bestion ◽  
...  
Keyword(s):  
Growth Rate ◽  
Temperature Dependence ◽  
Growth Rates ◽  
Carbon Allocation ◽  
Thermal Sensitivity ◽  
Potential Growth ◽  
Allocation Efficiency ◽  
Population Growth Rates ◽  
Performance Curves

Relating the temperature dependence of photosynthetic biomass production to underlying metabolic rates in autotrophs is crucial for predicting the effects of climatic temperature fluctuations on the carbon balance of ecosystems. We present a mathematical model that links thermal performance curves (TPCs) of photosynthesis, respiration, and carbon allocation efficiency to the exponential growth rate of a population of photosynthetic autotroph cells. Using experiments with the green alga, Chlorella vulgaris, we apply the model to show that the temperature dependence of carbon allocation efficiency is key to understanding responses of growth rates to warming at both ecological and longer-term evolutionary timescales. Finally, we assemble a dataset of multiple terrestrial and aquatic autotroph species to show that the effects of temperature-dependent carbon allocation efficiency on potential growth rate TPCs are expected to be consistent across taxa. In particular, both the thermal sensitivity and the optimal temperature of growth rates are expected to change significantly due to temperature dependence of carbon allocation efficiency alone. Our study provides a foundation for understanding how the temperature dependence of carbon allocation determines how population growth rates respond to temperature.

Temperature-dependence of the DnaA–DNA interaction and its effect on the autoregulation of dnaA expression

2012 ◽  
Vol 449 (2) ◽  
pp. 333-341 ◽  
Author(s):  
Chiara Saggioro ◽  
Anne Olliver ◽  
Bianca Sclavi
Keyword(s):  
Temperature Dependence ◽  
Binding Sites ◽  
Dna Interaction ◽  
Bacterial Dna ◽  
Dnaa Protein ◽  
High Affinity ◽  
Key Factor

The DnaA protein is a key factor for the regulation of the timing and synchrony of initiation of bacterial DNA replication. The transcription of the dnaA gene in Escherichia coli is regulated by two promoters, dnaAP1 and dnaAP2. The region between these two promoters contains several DnaA-binding sites that have been shown to play an important role in the negative auto-regulation of dnaA expression. The results obtained in the present study using an in vitro and in vivo quantitative analysis of the effect of mutations to the high-affinity DnaA sites reveal an additional effect of positive autoregulation. We investigated the role of transcription autoregulation in the change of dnaA expression as a function of temperature. While negative auto-regulation is lost at dnaAP1, the effects of both positive and negative autoregulation are maintained at the dnaAP2 promoter upon lowering the growth temperature. These observations can be explained by the results obtained in vitro showing a difference in the temperature-dependence of DnaA–ATP binding to its high- and low-affinity sites, resulting in a decrease in DnaA–ATP oligomerization at lower temperatures. The results of the present study underline the importance of the role for autoregulation of gene expression in the cellular adaptation to different growth temperatures.

3d—MAGNETISM OF THE RT4B COMPOUNDS

1993 ◽  
Vol 07 (01n03) ◽  
pp. 798-801
Author(s):  
T.T. DUNG ◽  
N.P. THUY ◽  
T.D. HIEN ◽  
N.M. HONG ◽  
D.C. KHAN ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Cell Volume ◽  
Unit Cell Volume ◽  
Magnetocrystalline Anisotropy ◽  
Close Correlation ◽  
Spin Reorientation ◽  
Lattice Constants ◽  
Spontaneous Magnetostriction ◽  
Relative Value

Spontaneous-magnetostriction and FMR studies are reported for the series Y(CO1−xFex)4B with x=0.00, 0.0125, 0.02 and 0.125. For the samples with composition x=0.00, 0.0125 and 0.02, step-like changes of the lattice constants a and c around the spin reorientation temperature TSR are observed. The relative values of the changes in ∆a/a and ∆c/c are of the order of 10−4 but are of opposite signs. The changes in the unit cell volume ∆V/V around TSR are negligible. In the temperature dependence of the average g-values of these samples, a step-like change with a relative value for ∆g/g of 10−2 has been deduced from FMR studies. These results point to a close correlation between the lattice constants and the magnetocrystalline anisotropy of the 3d-lattice and consequently to the role of the orbital moments in the anisotropic properties of the 3d-magnetism in the considered compounds.

Dominant Role of a Pseudogap in the Physics of the Colossal Magnetoresistive Oxides

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3389-3392 ◽  
Author(s):  
D. S. Dessau ◽  
T. Saitoh ◽  
C.-H. Park ◽  
Z.-X. Shen ◽  
Y. Moritomo ◽  
...  
Keyword(s):  
Dominant Role ◽  
Magnetic Ordering ◽  
High Energy ◽  
Spectral Weight ◽  
High Energy Resolution ◽  
Photoemission Spectroscopy ◽  
Colossal Magnetoresistive ◽  
Weight Density ◽  
Magnetic Ordering Temperature

We have performed direct electronic structure measurements of the colosssal magnetoresistive oxides using high energy resolution photoemission spectroscopy. A key result of these measurements is the discovery of a pseudogap which drastically supresses or completely removes the spectral weight (density of states) at the Fermi energy E F . It is shown that the pseudogap plays a dominant role in the "colossal" conductivity changes which occur across the magnetic ordering temperature. We briefly discuss possible origins for the pseudogap.

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