1,721,105 research outputs found
Impact of thinning on quantitative characteristics of Brant`s oak (Quercus brantii Lindl.) in Khorramabad Forests
No full textThis research aims at exploring 1) change in growth form in young coppice stands of Brant`s oak (Quercus brantii Lindl.) and 2) decrease in competition among individual sprouts in a sprout-clump as imposed by gradual thinning operation. We assessed the effect of different thinning treatments on growth of Brant`s oaks in Chegeni region-Khorram Abad along a 16-year period. The results of the first 4-years are presented here. Four thinning including increasing, decreasing, traditional and control treatments were established, each with 3 replications. The intensity of thinning in decreasing treatment was 32% of all sprouts in a sprout-clump. This was decreased in the next phases to 28%, 22% and 18%, respectively. The trend in the increasing treatment was vice versa. In traditional treatment, all sprouts except 1 to 2 in a sprout-clump were removed. The control treatment included no intervention. Prior to thinning, quantitative characteristics of sample trees were measured. In the last year of research, the measurements were repeated. The results showed that decreasing treatment imposed a considerably positive impact on growth in crown area and diameter of sprouts within the sprout clumps. In addition, traditional treatment was most influential in height growth of sprouts. This study proved the positive effect of thinning on quantitative characteristics of Brant`s oak. Furthermore, it showed that the more intensive the treatments are, the more positively they effect. As a conclusion, thinning operations can improve the unsustainable structural characteristics of young coppice stands within similar sites in Zagros forests of Iran
Interacting Boson Fermion-Fermion Model Calculation of the pi-h11/2 x nu-h11/2 Doublet Bands in 134Pr
No full textThe interacting boson fermion-fermion model is employed in the analysis of the positive-parity doublet bands in 134Pr. It is shown that stable triaxial deformation gives rise to the experimentally observed crossing between the yrast and yrare bands built on the pi-h11/2 x nu-h11/2 configuration. The collective structure of the yrast band is basically built on the ground-state band of the triaxial core, whereas the collective structure of the yrare band is predominantly based on the gamma band of the core. The mixing between the two bands increases with angular momentum. A constant energy spacing between the two lowest positive-parity bands is predicted in other odd-odd N=75 Nuclei with gamma soft potential energy surfaces
Investigation of extractable oil from Brant`s oak (Quercus brantii Lindl.) acorn in Chaharmahal and Bakhtiari Forests
No full textBrant`s oak(Quercus brantii Lindl.) is the most important woody species of Zagros forest ecosystems. Acorn of Brant`s oak is important as a nutrition source with its oil containing an appreciable amount of unsaturated fatty acids. Therefore proper estimation of the amount of extractable acorn oil can promote an opportunity of additional income for local communities. This research was carried out in Chaharmahal and Bakhtiari province to study the extractable oil from acorns of Brant`s oak. Initially 68 plots of 0.1 ha each were randomly established in the 10000 ha forest region. Quantitative traits of all trees were measured. Then acorns of 20 sample trees in different diameter classes in two groups of single-stem trees and sprout-clumps were collected and dried in an oven at 80 °C for 2 days. The oils of the dried powder from acorn were extracted by the Soxhlet method using petroleum ether (bp 40-60 °C), and were expressed on a dry-weight basis. The results indicated that the oil content of acorns was 8.56% (±0.89). Furthermore, the study site showed a 9.7 kg per ha potential of oil production. The most abundant fatty acids included oleic, linoleic and palmitic
Effect of thinning on growth of coppice Brant`s oak (Quercus brantii Lindl.) trees (Case study: Chegeni forest of Khorramabad)
No full textAs the first phase of a 16-year project, this research was carried out in a section of coppice Brant`s oak (Quercus brantii Lindl.) trees in Chegeni, Khorramabad, Lorestan province. We assessed the effect of different thinning treatments on growth of Brant`s oaks during a 4-year period. Three treatments with 3 replications were used including heavy (decreasing 30 percent of basal area), medium (decreasing 20 percent of basal area) and light (decreasing 10 percent of basal area) thinnings. One treatment was considered as control with no intervention. Quantitative characteristics of sample trees were measured prior to thinning. The measurements were repeated during 4 years to calculate the growth values. Based on results, heavy thinning had considerably positive impact on growth of diameter, height and basal area of sprouts as well as on growth of sprout-clumps crown area. It is concluded that thinning operations can improve the unsustainable structural characteristics of young coppice stands within Zagros forests
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dynamic Chirality in the Interacting Boson Fermion-Fermion Model
No full textThe chiral interpretation of twin bands in odd-odd nuclei was investigated in the interacting boson fermion-fermion model. The analysis of the wave functions has shown that the possibility far angular moments of the valence proton, neutron and care to find themselves in the favorable, almost orthogonal geometry is present, but not dominant. Such behavior is found to be similar in nuclei where bath the level energies and the electromagnetic decay properties display tile chiral pattern, as well as in those where only the level energies of the corresponding levels in the twin bands are close together. The difference in the structure of the two types of chiral candidates nuclei can be attributed to different beta and gamma fluctuations, induced by the exchange bason-fermion interaction of the interacting boson fermion-fermion model. In both cases the chirality is weak and dynamic
New Description of the Doublet Bands in Doubly Odd Nuclei
No full textThe experimentally observed delta I = 1 doublet bands in some odd-odd nuclei are analyzed within the orthosymplectic extensiou of the interacting vector boson model (IVBM). A new, purely collective interpretation of these bands is given on the basis of the obtained boson-fermion dynamical symmetry of the model. It is illustrated by its application to three odd-oddnuclei from the A ~ 130 region, namely 126Pr, 134Pr, and 132La. The theoretical predictions for the energy levels of the doublet bands as well as E2 and M 1 transition probabilities between the states of the yrast band in the last two nuclei are compared with experiment and the results of other theoretical approaches. The obtained results reveal the applicability 01 the orthosymplectic extension of the IVBM
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