Nonlinear theory of successions in forestry biogeocenoses: mathematical aspects

Systems analysis of biological phenomenon of succession has been carried out. The history of the subject and the current state of art are considered. Classification of both succession process as a whole and separate succession stages are proposed. Interaction between two main gears of succession – competition between plant species and their interaction with abiotic part of the biogeocoenose – are considered. Extreme nature of succession process and polygenetic structure of biogeocoenose, as a result of succession, are demonstrated

Crystallographic orientations of magnesiochromite inclusions in diamonds: what do they tell us?

We have studied by X-ray diffractometry the crystallographic orientation relationships (CORs) between magnesiochromite (mchr) inclusions and their diamond hosts in gem-quality stones from the mines Udachnaya (Siberian Russia), Damtshaa (Botswana) and Panda (Canada); in total 36 inclusions in 23 diamonds. In nearly half of the cases (n = 17), [111]mchr is parallel within error to [111]diamond, but the angular misorientation for other crystallographic directions is generally significant. This relationship can be described as a case of rotational statistical COR, in which inclusion and host share a single axis (1 df). The remaining mchr\u2013diamond pairs (n = 19) have a random COR (2 df). The presence of a rotational statistical COR indicates that the inclusions have physically interacted with the diamond before their final incorporation. Of all possible physical processes that may have influenced mchr orientation, those driven by surface interactions are not considered likely because of the presence of fluid films around the inclusions. Mechanical interaction between euhedral crystals in a fluid-rich environment is therefore proposed as the most likely mechanism to produce the observed rotational COR. In this scenario, neither a rotational nor a random COR can provide information on the relative timing of growth of mchr and diamond. Some multiple, iso-oriented inclusions within single diamonds, however, indicate that mchr was partially dissolved during diamond growth, suggesting a protogenetic origin of these inclusions

A NEW INTERPRETATION OF THE COMPOUND STROBILAR STRUCTURES OF CORDAITES AND CONIFERS

The compound strobili of cordaites and conifers (e.g. Amentotaxiis) is interpreted by the application, of the telome theory. Homologies of organization among the strobilar structures and the pinnate phylloclade of Phyllocladus are also suggested

Archaean and Proterozoic diamond growth from contrasting styles of large-scale magmatism

Precise dating of diamond growth is required to understand the interior workings of the early Earth and the deep carbon cycle. Here we report Sm-Nd isotope data from 26 individual garnet inclusions from 26 harzburgitic diamonds from Venetia, South Africa. Garnet inclusions and host diamonds comprise two compositional suites formed under markedly different conditions and define two isochrons, one Archaean (2.95 Ga) and one Proterozoic (1.15 Ga). The Archaean diamond suite formed from relatively cool fluid-dominated metasomatism during rifting of the southern shelf of the Zimbabwe Craton. The 1.8 billion years younger Proterozoic diamond suite formed by melt-dominated metasomatism related to the 1.1 Ga Umkondo Large Igneous Province. The results demonstrate that resolving the time of diamond growth events requires dating of individual inclusions, and that there was a major change in the magmatic processes responsible for harzburgitic diamond formation beneath Venetia from the Archaean to the Proterozoic

Plant communities in the lysimeter experiment of ash reclamation in the Dolna Odra Power Station in Nowe Czarnowo (Poland)

The aim of the study was to determine the type and origin of plant communities on an area of 4 lysimeters (35 m2 each) filed with ash and covered with two superlayers 12 years after the beginning of the experience. The paper presents the species of grasses sown in 2003, their sward participation then and the flrist status in 2015. Phytosociological records were taken using the Braun-Blanquet’s method, distinguished plant communities, the syngenesis of the recognized phytocoenoses was defied. The results allowed to determine the advantage of the ruderal synanthropic communities: Artemisio-Tanacetetum vulgaris Br-Bl. 1931 corr. 1949 (in L-2), Leonuro Ballotetum nigrae (in L-3), a community with Rubus caesius (in L-4) over the natural auxochoric Calamagrostietum epigeji Juraszek 1928 (in L-1). Their current state is referred to as a hull form. However, due to the presence of the expansive species characteristic of the above-mentioned communities, continued development can be expected towards fully developed phytocoenoses. The thesis founded about the inflence of the neighboring forest communities on the species composition of the vegetation of the subject has not been confimed. There were only three forest and scrub species with a negligible sward participation

The (100), (111) and (110) surfaces of diamond: an ab initio B3LYP study

We present an accurate ab initio study of the structure and surface energy of the low-index (100),(111) and (110) diamond faces, by using the hybrid Hartree-Fock/Density Functional B3LYPHamiltonian and a localized all-electron Gaussian-type basis set. A 2D periodic slab model has been adopted, for which convergence on both structural and energetic parameters has been thoroughly investigated. For all the three surfaces, possible relaxations and reconstructions have been considered; a detailed geometrical characterization is provided for the most stable structure of each orientation. Surface energy is discussed for all the investigated faces

Above-ground phytomass dynamics in autogenic succession of an ecosystem

It was found that a regular growth in the above-ground phytomass occurs during autogenic succession, which is approximated by logarithmic dependence with high reliability indices. External, including anthropogenic, effects on the process of succession lead to a decrease in the rate of phytomass growth. Besides, the rate of phytomass changes is influenced by endo-ecogenesis caused by various plant species, entering the ecosystem at certain stages of succession. The above-ground phytomass portioning behaviour makes it possible to use it to create a unified indicator of dynamics. Each plant species can be only within certain indicators of the phytomass of their plant communities. At the same time, there is a normal distribution of the projective cover value. This allows us to work out synphytoindication methods for determining the dynamics indicato

Vascular plant biodiversity richness and endemo relictness of the karst mountains Prenj–Čvrsnica–Čabulja in Bosnia and Herzegovina (W. Balkan)

The complex of karstic mountains Prenj-Čvrsnica and Čabulja in Herzegovina (w. Balkan) is characterized by high level of both geomorphology and biodiversity richness. This has been confirmed by a research of plant communities, their structure and dynamics, which took place throughout several seasons from 2005 to 2008. In the investigated area the vegetation cover, as a reliable indicator for specific karstic circumstances, is being differentiated in a great number of syntaxa (plant communities) that encompass over 2,500 vascular plants. On the surface of about 100,000 ha identified were up to 236 plant associations, 116 alliances and 63 vegetation orders that belong to 34 classes. This amounts 34% of total of vegetation classes at the European level and 100% of so far known vegetation classes in Bosnia and Herzegovina, over 80% of classes at the level of Montenegro and Croatia.There have been identified nearly 450 endemic and relict species, which is why most of the identified communities are endemic and relict ones, not only at the level of association but also at the level of higher syntaxonomic categories, such as alliance and order. The highest diversity level characterizes those communities that make a direct contact with the calcareous geological foundation either in rock crevices or screes on limestone. That high level of floristic and vegetation richness places this area among the most diverse areas both in Europe and whole Mediterranean.That high level of floristic and vegetation richness places this area among the most diverse areas both in Europe and whole Mediterranean. Such pattern of vegetation (syntaxonomy) and floristic diversity confirms the unique role of dinaric-herzegovina karst as a complex of unrepeatable ecological factors on global scale

Primary carbonatite melt from deeply subducted oceanic crust

Partial melting in the Earth's mantle plays an important part in generating the geochemical and isotopic diversity observed in volcanic rocks at the surface. Identifying the composition of these primary melts in the mantle is crucial for establishing links between mantle geochemical 'reservoirs' and fundamental geodynamic processes. Mineral inclusions in natural diamonds have provided a unique window into such deep mantle processes. Here we provide experimental and geochemical evidence that silicate mineral inclusions in diamonds from Juina, Brazil, crystallized from primary and evolved carbonatite melts in the mantle transition zone and deep upper mantle. The incompatible trace element abundances calculated for a melt coexisting with a calcium-titanium-silicate perovskite inclusion indicate deep melting of carbonated oceanic crust, probably at transition-zone depths. Further to perovskite, calcic-majorite garnet inclusions record crystallization in the deep upper mantle from an evolved melt that closely resembles estimates of primitive carbonatite on the basis of volcanic rocks. Small-degree melts of subducted crust can be viewed as agents of chemical mass-transfer in the upper mantle and transition zone, leaving a chemical imprint of ocean crust that can possibly endure for billions of years.4 page(s