Medium Strong Correlation Research Articles

The C IV Baldwin effect in quasi-stellar objects from Seventh Data Release of the Sloan Digital Sky Survey

Using the properties of SDSS DR7 QSOs catalog from Shen et al., the Baldwin effect, its slope evolution, the underlying drive for a large sample of 35019 QSOs with reliable spectral analysis are investigated. We find that the Baldwin effect exists in this large QSOs sample, which is almost the same in 11 different redshift bins, up to $z\sim 5$. The slope is -0.238 by the BCES (\civ\ EW depends on the continuum), -0.787 by the BCES bisector. For 11 redshift-bins, there is an increasing of the Baldwin effect slope from $z\sim1.5$ to $z\sim2.0$. From $z\sim2.0$ to $z\sim5.0$, the slope change is not clear considering their uncertainties or larger redshift bins. There is a strong correlation between the rest-frame \civ\ EW and \civ-based \mbh while the relation between the \civ\ EW and \mgii-based \mbh is very weak. With the correction of \civ-based \mbh from the \civ\ blueshift relative to \mgii, we suggest that this strong correlation is due to the bias of the \civ-based \mbh, with respect to that from the \mgii\ line. Considering the \mgii-based \mbh, a medium strong correlation is found between the \civ\ EW and the Eddington ratio, which implies that the Eddington ratio seems to be a better underlying physical parameter than the central black hole mass.

Međuovisnost industrijalizacije i nekih oblika socijalne mobilnosti stanovništva u sisačkom i petrinjskom kraju

U prvom dijelu rada analiziraju se odabrani oblici socijalne mobilnosti stanovništva sisačkog i petrinjskog kraja između 1961. i 2001. godine: industrijska zaposlenost, deagrarizacija i razina obrazovanosti stanovništva. Potom se istražuje međuovisnost zaposlenosti stanovništva u industriji i drugih dvaju oblika socijalne mobilnosti. U tu svrhu izračunati su statistički pokazatelji jakosti veza između navedenih pojava (koeficijent jednostavne linearne korelacije). Rezultati su uputili na postojanje slabe pozitivne korelacije između industrijske zaposlenosti i deagrarizacije u sisačkom kraju, odnosno na srednje jaku korelaciju u petrinjskom kraju. Nešto jača korelacija ustanovljena je između industrijske zaposlenosti i obrazovanosti stanovništva.

GROWTH AND BIOMASS OF TWO-YEAR-OLD SEEDLINGS OF EUROPEAN CHESTNUT DERIVED FROM THE HALF-SIB FAMILIES OF DIFFERENT ORIGIN

In the spring of 2005, seeds collected in twelve different half-sib families being at the age of 40 years and originated from mother trees grown on four different localities of Slovakia were used to established an experimental plot in the forest nursery Hladomer, Slovakia. At the age of 2 years, in each of 12 sets of seedlings 15 seedlings differing in growth performance were selected (5 from each replication) and subjected to morphometric analysis. In each seedling 5 biometric characteristics (stem height, stem diameter, root length, root diameter, diameter of the root collar), 3 single biomass characteristics (biomass of the stem and branches, root biomass, leaf biomass), 2 combined biomass characteristics (aboveground biomass and total seedling biomass) and three derived parameters (index of annual stem height increment, index of annual stem diameter increment and foliage ratio -proportion of leaf dry matter and total dry aboveground matter of the seedling) were evaluated. All characteristics under study except indices and foliage ratio exhibited significantly highest mean values in the seedlings derived from three half-sib families of Horne Lefantovce origin, particularly from the HL A family. The seedlings derived from this family showed significantly highest values of aboveground and underground biomass but the second lowest foliage ratio. This suggests the high effective use of leaves for biomass production in these seedlings. Foliage ratio was in medium strong negative correlation with most of the growth and biomass characteristics.

Dynamics of tree species composition and characteristics of available space utilization in the natural forest of the National Nature Reserve Hrončokovský Grúň

The paper deals with changes in the diameter structure of particular tree species as well as with the selected production characteristics in the mixed virgin forest Hrončokovský Grúň. The object of the analysis was the diameter structure of particular tree species in developmental stages of virgin forest. The data were collected in the years 1972, 1982, 1992 and 2002 on permanent research plots 71.5 × 70 m (0.5 ha) in size. Diameter frequencies for particular tree species were approximated with the curves. The goal was to evaluate their mortality or vitality according to the strength of the correlation in developmental stages of the virgin forest. A strong correlation was confirmed in the advanced phase of the growth stage, whereas the strongest correlation was recorded for the ash. Beech as a virgin forest bearer had a medium strong correlation. For the advanced phase of the optimum stage lower values of the correlation coefficients were determined for all tree species. The growth vitality and thus lower mortality was characteristic of maple and ash. Beech as a structure bearer is characterized by higher mortality and therefore a weaker correlation. In the breakdown stage the highest mortality was found for the fir, which is confirmed by the lowest value of the correlation coefficient. In the advanced phase of the optimum stage the highest mortality was recorded for the beech. The analysis of growth and production relationships was conducted on the transects of 3 permanent research plots 10 × 71.5 m in size (i.e. total size of 2,145 m<sup>2</sup>). The analysis of the growth relationships between the crown and stem volume confirmed a strong correlation for beech and fir despite the fact they are present in the entire height profile of the virgin forest. The reason is that both of them are the shade-tolerant tree species. High correlation coefficients for maple and ash (<I>R</I> = 0.82 and <I>R</I> = 0.84) are the evidence of a distinctive influence of the assimilatory apparatus on the stem volume. The reason is the fact that both tree species are situated in the upper tree layer and have relatively enough space for the crown growth. The productive utilization of the crown space in the virgin forest confirmed the dominance of the beech as a structure bearer.