scholarly journals The energetic cost of filtration by demosponges and their behavioural response to ambient currents

2016 ◽  
Vol 220 (6) ◽  
pp. 995-1007 ◽  
Author(s):  
Danielle A. Ludeman ◽  
Matthew A. Reidenbach ◽  
Sally P. Leys
Keyword(s):  
Behavioural Response ◽  
Energetic Cost ◽  
Ambient Currents

scholarly journals Correction: The energetic cost of filtration by demosponges and their behavioural response to ambient currents

2017 ◽  
Vol 220 (24) ◽  
pp. 4743-4744 ◽  
Author(s):  
Danielle A. Ludeman ◽  
Matthew A. Reidenbach ◽  
Sally P. Leys
Keyword(s):  
Behavioural Response ◽  
Energetic Cost ◽  
Ambient Currents

Quasi-Barrierless Submolecular Motion in Mechanically Interlocked Carbon Nanotubes

2020 ◽  
Author(s):  
Julia Villalva ◽  
Belén Nieto-Ortega ◽  
Manuel Melle-Franco ◽  
Emilio Pérez
Keyword(s):  
Density Functional ◽  
Close Contact ◽  
Tight Binding ◽  
Energetic Cost ◽  
Molecular Fragments ◽  
Activation Barriers ◽  
Flat Surfaces ◽  
Different Types ◽  
Atomically Flat ◽  
Derivatives Of

The motion of molecular fragments in close contact with atomically flat surfaces is still not fully understood. Does a more favourable interaction imply a larger barrier towards motion even if there are no obvious minima? Here, we use mechanically interlocked rotaxane-type derivatives of SWNTs (MINTs) featuring four different types of macrocycles with significantly different affinities for the SWNT thread as models to study this problem. Using molecular dynamics, we find that there is no direct correlation between the interaction energy of the macrocycle with the SWNT and its ability to move along or around it. Density functional tight-binding calculations reveal small (<2.5 Kcal·mol-1) activation barriers, the height of which correlates with the commensurability of the aromatic moieties in the macrocycle with the SWNT. Our results show that macrocycles in MINTs rotate and translate freely around and along SWNTs at room temperature, with an energetic cost lower than the rotation around the C−C bond in ethane.<br>

SAMPL6 Octanol-Water Partition Coefficients from Alchemical Free Energy Calculations with MBIS Atomic Charges

2019 ◽  
Author(s):  
Maximiliano Riquelme ◽  
Esteban Vöhringer-Martinez
Keyword(s):  
Free Energy ◽  
Electron Density ◽  
Free Energy Calculations ◽  
Basis Set ◽  
Energetic Cost ◽  
Atomic Charges ◽  
Free Energies ◽  
Energy Calculations ◽  
Alchemical Free Energy ◽  
Alchemical Free Energy Calculations

In molecular modeling the description of the interactions between molecules forms the basis for a correct prediction of macroscopic observables. Here, we derive atomic charges from the implicitly polarized electron density of eleven molecules in the SAMPL6 challenge using the Hirshfeld-I and Minimal Basis Set Iterative Stockholder(MBIS) partitioning method. These atomic charges combined with other parameters in the GAFF force field and different water/octanol models were then used in alchemical free energy calculations to obtain hydration and solvation free energies, which after correction for the polarization cost, result in the blind prediction of the partition coefficient. From the tested partitioning methods and water models the S-MBIS atomic charges with the TIP3P water model presented the smallest deviation from the experiment. Conformational dependence of the free energies and the energetic cost associated with the polarization of the electron density are discussed.

scholarly journals Empirical study of spatial differentiation of youth unemployment in Russia

2016 ◽  
Vol 66 (3) ◽  
pp. 507-526 ◽  
Author(s):  
Tatiana Blinova ◽  
Vladimir Markov ◽  
Viktor Rusanovskiy
Keyword(s):  
Labour Market ◽  
Age Groups ◽  
Spatial Differentiation ◽  
Youth Unemployment ◽  
Behavioural Response ◽  
Economic Effects ◽  
Group Differences ◽  
Unemployment Rates ◽  
Youth Labour Market ◽  
Interregional Differentiation

The purpose of the study is to conduct a statistical analysis and to perform a quantitative assessment of the degree and the dynamics of the interregional differences in youth unemployment in Russia between 2005 and 2013. We decompose the interregional differentiation into “within-group” and “between-group” differences. We also analyse the dynamics of the within-group and between-group differences and estimate their contribution to changes in the interregional differentiation of youth unemployment. Additionally, we estimate the degree and the dynamics of the interregional differences of the youth labour market in Russia in times of crisis and recovery growth. The results show a reduction in the interregional differences in unemployment rates between 2005 and 2008, while in 2009–2013, the interregional differentiation of the labour market increased. We found that the socio-economic effects of youth unemployment, as well as the behavioural response to economic shocks in the age groups of 15–19 and 20–29 years were significantly different.

OESTROGEN-PROGESTERONE RELATIONSHIPS IN THE INDUCTION OF OESTRUS IN SPAYED HEIFERS

1969 ◽  
Vol 45 (1) ◽  
pp. 99-109 ◽  
Author(s):  
M. J. CARRICK ◽  
J. N. SHELTON
Keyword(s):  
Behavioural Response ◽  
Normal Response ◽  
Oestradiol Benzoate ◽  
Small Doses ◽  
Refractory State ◽  
Increased Sensitivity ◽  
Repeated Doses ◽  
Effective Doses ◽  
Response Line ◽  
Normal Sensitivity

SUMMARY Experiments were conducted to examine the behavioural response of spayed heifers to oestrogen, and its modification by progesterone. In two groups of heifers, the median effective doses (MED) of oestradiol benzoate (ODB) were 121 and 132 μg. Repeated doses of ODB at physiological levels did not induce a state of refractoriness; in this respect the heifer is dissimilar to the ewe. However, repeated doses of 10 mg. ODB induced refractoriness to 400 μg. ODB. When such refractory heifers were treated with 10 mg. progesterone/day for 5 days, they showed a normal response to 400 μg. ODB given 3 days later. This return to normal sensitivity was not sustained, and pretreatment with progesterone was necessary for a normal response to subsequent small doses of ODB. The transient removal of the refractory state appears not to be due to a simple synergistic effect of residual progesterone, but to an effect of preconditioning a neural centre to respond to oestrogen. Increasing the duration of pretreatment with progesterone beyond 5 days did not result in a greater sensitivity to ODB. Pretreatment with progesterone in heifers not made refractory to ODB did not result in an increased sensitivity to ODB. Moreover, up to 7 days after termination of the progesterone treatment, the response to ODB was reduced and the slope of the dose-response line was less steep than when ODB was injected alone. The reduction of the response was more pronounced with 40 mg. progesterone/day than with 10 mg. The possible significance of these results in intact animals is discussed.

scholarly journals Prey Size Decline as a Unifying Ecological Selecting Agent in Pleistocene Human Evolution

Quaternary ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 7
Author(s):  
Miki Ben-Dor ◽  
Ran Barkai
Keyword(s):  
Prey Size ◽  
Prey Availability ◽  
Stone Tool ◽  
Foraging Efficiency ◽  
Energetic Cost ◽  
Large Prey ◽  
Biomass Density ◽  
Cultural Changes ◽  
Progressive Decline ◽  
Brain Expansion

We hypothesize that megafauna extinctions throughout the Pleistocene, that led to a progressive decline in large prey availability, were a primary selecting agent in key evolutionary and cultural changes in human prehistory. The Pleistocene human past is characterized by a series of transformations that include the evolution of new physiological traits and the adoption, assimilation, and replacement of cultural and behavioral patterns. Some changes, such as brain expansion, use of fire, developments in stone-tool technologies, or the scale of resource intensification, were uncharacteristically progressive. We previously hypothesized that humans specialized in acquiring large prey because of their higher foraging efficiency, high biomass density, higher fat content, and the use of less complex tools for their acquisition. Here, we argue that the need to mitigate the additional energetic cost of acquiring progressively smaller prey may have been an ecological selecting agent in fundamental adaptive modes demonstrated in the Paleolithic archaeological record. We describe several potential associations between prey size decline and specific evolutionary and cultural changes that might have been driven by the need to adapt to increased energetic demands while hunting and processing smaller and smaller game.

scholarly journals The dose makes the poison: Non-linear behavioural response to CO2-induced aquatic acidification in zebrafish (Danio rerio)

2021 ◽  
Vol 778 ◽  
pp. 146320
Author(s):  
Trevor J. Hamilton ◽  
Nicole Hurst Radke ◽  
Jasmin Bajwa ◽  
Shayna Chaput ◽  
Martin Tresguerres
Keyword(s):  
Danio Rerio ◽  
Behavioural Response ◽  
Non Linear ◽  
Aquatic Acidification

scholarly journals Quantifying the energetic cost of food quality constraints on resting metabolism to integrate nutritional and metabolic ecology

2021 ◽  
Author(s):  
Thomas Ruiz ◽  
Apostolos‐Manuel Koussoroplis ◽  
Michael Danger ◽  
Jean‐Pierre Aguer ◽  
Nicole Morel‐Desrosiers ◽  
...  
Keyword(s):  
Food Quality ◽  
Energetic Cost ◽  
Metabolic Ecology ◽  
Resting Metabolism

scholarly journals Single bacterial resolvases first exploit, then constrain intrinsic dynamics of the Holliday junction to direct recombination

2021 ◽  
Author(s):  
Sujay Ray ◽  
Nibedita Pal ◽  
Nils G Walter
Keyword(s):  
Cluster Analysis ◽  
Homologous Recombination ◽  
Single Molecule ◽  
Holliday Junction ◽  
Energetic Cost ◽  
Genomic Integrity ◽  
Dna Molecules ◽  
Single Molecule Fluorescence ◽  
And Cluster Analysis ◽  
Fluorescence Observation

Abstract Homologous recombination forms and resolves an entangled DNA Holliday Junction (HJ) crucial for achieving genetic reshuffling and genome repair. To maintain genomic integrity, specialized resolvase enzymes cleave the entangled DNA into two discrete DNA molecules. However, it is unclear how two similar stacking isomers are distinguished, and how a cognate sequence is found and recognized to achieve accurate recombination. We here use single-molecule fluorescence observation and cluster analysis to examine how prototypic bacterial resolvase RuvC singles out two of the four HJ strands and achieves sequence-specific cleavage. We find that RuvC first exploits, then constrains the dynamics of intrinsic HJ isomer exchange at a sampled branch position to direct cleavage toward the catalytically competent HJ conformation and sequence, thus controlling recombination output at minimal energetic cost. Our model of rapid DNA scanning followed by ‘snap-locking’ of a cognate sequence is strikingly consistent with the conformational proofreading of other DNA-modifying enzymes.

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