Volume changes in HgTe upon melting and heating

Data on volumetric changes of HgTe during melting and heating the melt were obtained by means of the gamma-ray attenuation technique. Negative volumetric effect has been established upon HgTe melting. The baric coefficient value of melting temperature dT/dP calculated by the Clapeyron-Clausius equation is compared with the same value obtained on the (p-T) diagram of the Hg-Te system. The dependence density versus on temperature for liquid HgTe increases from its melting point at 943 K to maximum value at 1023 K and than normal thermal expansion established. These anomalous changes of density in liquid HgTe could be explained on the basis of the "after-melting" effect and fully described in terms of the ideal associated solution model assuming HgTe and Hg2Te3 associates

Limited Phylogeographic Signal in Sex-Linked and Autosomal Loci Despite Geographically, Ecologically, and Phenotypically Concordant Structure of mtDNA Variation in the Holarctic Avian Genus Eremophila

Phylogeographic studies of Holarctic birds are challenging because they involve vast geographic scale, complex glacial history, extensive phenotypic variation, and heterogeneous taxonomic treatment across countries, all of which require large sample sizes. Knowledge about the quality of phylogeographic information provided by different loci is crucial for study design. We use sequences of one mtDNA gene, one sex-linked intron, and one autosomal intron to elucidate large scale phylogeographic patterns in the Holarctic lark genus Eremophila. The mtDNA ND2 gene identified six geographically, ecologically, and phenotypically concordant clades in the Palearctic that diverged in the Early - Middle Pleistocene and suggested paraphyly of the horned lark (E. alpestris) with respect to the Temminck’s lark (E. bilopha). In the Nearctic, ND2 identified five subclades which diverged in the Late Pleistocene. They overlapped geographically and were not concordant phenotypically or ecologically. Nuclear alleles provided little information on geographic structuring of genetic variation in horned larks beyond supporting the monophyly of Eremophila and paraphyly of the horned lark. Multilocus species trees based on two nuclear or all three loci provided poor support for haplogroups identified by mtDNA. The node ages calculated using mtDNA were consistent with the available paleontological data, whereas individual nuclear loci and multilocus species trees appeared to underestimate node ages. We argue that mtDNA is capable of discovering independent evolutionary units within avian taxa and can provide a reasonable phylogeographic hypothesis when geographic scale, geologic history, and phenotypic variation in the study system are too complex for proposing reasonable a priori hypotheses required for multilocus methods. Finally, we suggest splitting the currently recognized horned lark into five Palearctic and one Nearctic species