The University of Tartu is a classical university in the city of Tartu, Estonia. University of Tartu is the national university of Estonia; it is the biggest and highest-ranked university in Estonia. The University of Tartu is a member of the Coimbra Group and the Utrecht Network, and was established by King Gustavus Adolphus of Sweden in 1632, thus being one of the oldest universities in Northern Europe. Wikipedia.
Teder T.,University of Tartu
Functional Ecology | Year: 2014
The degree and direction of sexual size dimorphism (SSD) vary greatly between animal species. At the ontogenetic level, SSD may result from sex differences in birth size, growth rate and/or development time. Nevertheless, evidence concerning proximate causation of SSD is scattered, and the data used to infer ontogenetic determinants of SSD have not always been appropriate for this purpose. I use a comprehensive literature-derived data base of relevant sex-specific traits on 169 species to address the significance of sex differences in larval development time (SDTD) as a proximate source of SSD in insects. In a clear majority of species (79%), SSD and SDTD were qualitatively congruent, that is, the larger sex had also a longer larval development. In strongly size-dimorphic species, the qualitative correspondence between SSD and SDTD was nearly universal. Consistently, in a phylogenetically diverse array of insect clades, SDTD increased with increasing SSD across species. The results indicate that the evolution and maintenance of high SSD values are rarely possible without a prolonged development of the larger sex. The role of sex differences in growth rate as the ontogenetic determinant of SSD in insects requires further studies that should ideally be based on detailed monitoring of larval growth schedules. The increase in SDTD with increasing SSD is consistent with the idea that the widespread phenomenon of protandry (the emergence of male adults before females) may not be selected for per se, but rather may primarily be an incidental by-product of other selection pressures. © 2013 The Author. Functional Ecology © 2013 British Ecological Society.
Harro J.,University of Tartu
Pharmacology and Therapeutics | Year: 2010
Susceptibility to affective disorders is individually different, and determined both by genetic variance and life events that cause significant differences in the CNS structure and function between individual subjects. Therefore it is plausible that search for the inter-individual differences in endophenotypes that mediate the effects of causal factors, both genetic and environmental, will reveal the substrates for vulnerability, help to clarify pathogenetic mechanisms, and possibly aid in developing strategies to discover better, more personalized treatments. This review first examines comparatively a number of animal models of human affect and affect-related disorders that rely on persistent inter-individual differences, and then highlights some of the neurobiological findings in these models that are compatible with much of research in human behavioural and personality traits. Many behaviours occur in specific combinations in several models, but often remarkable dissociations are observed, providing a variety of constellations of traits. It is concluded that more systematic comparative experimentation on behaviour and neurobiology in different models is warranted to reveal possible "building blocks" of affect-related personality common in animals and humans. Looking into the perspectives in psychopharmacology the focus is placed on probable associations of inter-individual differences with brain structure and function, personality and coping strategies, and psychiatric vulnerability, highlighting some unexpected interactions between vulnerability endophenotypes, adverse life events, and behavioural traits. It is argued that further studies on inter-individual differences in affect and underlying neurobiology should include formal modeling of their epistatic, hierarchical and dynamic nature. © 2009 Elsevier Inc. All rights reserved.
Kalm V.,University of Tartu
Quaternary Science Reviews | Year: 2012
A review of scientific literature, geological maps and available previous digital data on ice-marginal positions, glacial landforms and sediment distribution are utilised to reconstruct ice streams and lobes, and the maximum (LGM) and subsequent recessional ice-marginal positions of the Scandinavian Ice Sheet (SIS) southeast of the Baltic Sea. This paper presents preliminary results of the ongoing research that aims to build a Geographic Information System (GIS) based model on the extent and timing of the last SIS in the area between its maximum extent and the Baltic Sea. Digitized subglacial bedforms, ice marginal and other glacial landforms and features from published sources are compared and validated against digital elevation model (DEM). This has allowed specifying, revising and questioning the location of the LGM, and to interpret and correlate the post-LGM ice streams with marginal positions. Morphological evidence demonstrates that large ice streams of between 100 and 300. km lengths, were in operation ca 2-3. ka after the LGM and formed the Middle and North Lithuanian end moraines. Ice streams from the Onega and White Sea basins had high lateral slopes and clearly channelled flow while the ice streams that drained the ice sheet through the Ladoga-Ilmen depression and in the eastern Baltic usually had a fan-shaped flow pattern and morphologically unclear lateral slopes. In elevated areas and highlands that are located between ice streams a crossing of lineated bedforms is common. One set of the crossing lineations on Zemaitia, Eastern Kursa, Vidzeme, Haanja, Latgale and Sudoma highlands that are 200-350. km inside of the LGM margin, has northwest-southeast orientation that in general conforms to the direction of ice flow during the LGM and Baltija phases. It is expected that the presented compilation will stimulate discussions and scrutiny of earlier published data and generate ideas for future investigations. © 2010 Elsevier Ltd.
Garcia-Sosa A.T.,University of Tartu
Journal of Chemical Information and Modeling | Year: 2013
Some water molecules in binding sites are important for intermolecular interactions and stability. The way binding site explicit water molecules are dealt with affects the diversity and nature of designed ligand chemical structures and properties. The strategies commonly employed frequently assume that a gain in binding affinity will be achieved by their targeting or neglect. However, in the present work, 2332 high-resolution X-ray crystal structures of hydrated and nonhydrated, drug and nondrug compounds in biomolecular complexes with reported Ki or Kd show that compounds that use tightly bound, bridging water molecules are as potent as those that do not. The distribution of their energies, physicochemical properties, and ligand efficiency indices were compared for statistical significance, and the results were confirmed using 2000 permutation runs. Ligand cases were also split into agonists and antagonists, and crystal structure pairs with differing tightly bound water molecules were also compared. In addition, agonists and antagonists that use tightly bound water bridges are smaller, less lipophilic, and less planar; have deeper ligand efficiency indices; and in general, possess better physicochemical properties for further development. Therefore, tightly bound, bridging water molecules may in some cases be replaced and targeted as a strategy, though sometimes keeping them as bridges may be better from a pharmacodynamic perspective. The results suggest general indications on tightly hydrated and nontightly hydrated compounds in binding sites and practical considerations to adopt a strategy in drug and molecular design when faced with this special type of water molecules. There are also benefits of lower log P and better developability for tightly hydrated compounds, while stronger potency is not always required or beneficial. The hydrated binding site may be one of the many structure conformations available to the receptor, and different ligands will have a different ability to select either hydrated or nonhydrated receptor binding site conformations. Compounds may thus be designed, and if a tightly bound, bridging water molecule is observed in the binding site, attempts to replace it should only be made if the subsequent ligand modification would improve also its ligand efficiency, enthalpy, specificity, and pharmacokinetic properties. If the modification does succeed in replacing the tightly bound, bridging water molecule, it will have at least achieved benefits for ligand optimization and development independently of either positive or negative change in binding affinity outcome. © 2013 American Chemical Society.
Peet V.,University of Tartu
Optics Letters | Year: 2011
For a light beam focused through a biaxial crystal along one of its optical axes, the effect of internal conical refraction in the crystal leads to the formation in the focal image plane of two bright rings separated by a dark ring. It is shown that, with circularly polarized Laguerre-Gauss LGℓ 0 beams entering the crystal, this classical double-ring pattern is transformed into a multiring one consisting of ℓ + 2 bright rings. © 2011 Optical Society of America.