Fungal endophyte communities in declining and vital oak (Quercus robur L.) trees

The role of microbiome in tree health is receiving increasing interest in forest pathology research. This study focuses on the abundance and diversity of fungal endophytes in pedunculate oak (Quercus robur L.) differentiating in vitality. Earlier studies with peri-urban, young oak trees have indicated that fungal endophyte diversity in woody tissues of oaks is lower in highly vital trees. In this thesis, the hypothesis that declining trees harbour a higher fungal diversity was tested in a production forest setting, using older trees. To test the hypothesis, endophytes were isolated from bark and xylem of Quercus robur L., using two types of agar-media to select for a broad range of fungi. Based on the morphological characters of the colonies the isolates grouped into 38 morphotypes and a group of singletons, and the frequency and diversity of fungi in different tissue types (bark and xylem of differently vital trees) was compared. The results indicate that endophyte communities of Quercus robur L. xylem and bark are more diverse in trees showing some symptoms of decline in comparison to the seemingly healthy-looking trees, but that the diversity was reduced in the most strongly declined trees. In addition, the results confirmed the earlier findings showing that bark associated endophyte communities are more diverse than xylem associated communities. I also found that samples of water agar harbored different assemblage of morphotypes comparing to malt extract agar. Future studies are required to characterize fungal endophyte communities in order to evaluate the interactions that take place within the complex, understudied networks and apply them in ecosystem management

Sunfleck properties from time series of fluctuating light

Light in canopies is highly dynamic since the strength and composition of incoming radiation is determined by the wind and the Sun's trajectory and by canopy structure. For this highly dynamic environment, we mathematically defined sunflecks as periods of high irradiance relative to the background light environment. They can account for a large proportion of the light available for photosynthesis. Based on high-frequency irradiance measurements with a CCD array spectroradiometer, we investigated how the frequency of measurement affects what we define as sunflecks. Do different plant canopies produce sunflecks with different properties? How does the spectral composition and strength of irradiance in the shade vary during a sunfleck? Our results suggest that high-frequency measurements improved our description of light fluctuations and led to the detection of shorter, more frequent and intense sunflecks. We found that shorter wind-induced sunflecks contribute most of the irradiance attributable to sunflecks, contrary to previous reports from both forests and crops. Large variations in sunfleck properties related to canopy depth and species, including distinct spectral composition under shade and sunflecks, suggest that mapping canopy structural traits may help us model photosynthesis dynamically.Peer reviewe

Evalution of argumentation with generally-known facts in the court decisions of Latvian Court of Cassation.

Bakalaura darbs veltīts argumentācijas ar vispārzināmiem faktiem vērtējumam Latvijas kasācijas instances tiesu nolēmumos. Darba mērķis ir izpētīt vispārzināmā fakta veidojošos aspektus, kā arī atrast vispārzināmā fakta kļūdas tiesu nolēmumos. Lai sasniegtu bakalaura darba mērķi, autore ir aplūkojusi latviešu, angļu un vācu valodā dažādas grāmatas, publikācijas, interneta resursus, normatīvos aktus un Latvijas Republikas Augstākās tiesas praksi. Bakalaura darba pētījuma rezultātā izstrādāti secinājumi un priekšlikumi vispārzināmā fakta konstatēšanai, klasificēšanai, apstrīdēšanai un pamatošanai.This Bachelor's thesis is devoted to evaluation of argumentation with generally-known facts in the court decisions of Latvian Court of Cassation. The aim of the thesis is to study the aspects of the generally-known fact, as well as to find errors of the generally-known fact in court decisions. In order to achieve the aim of this Bachelor's thesis, the author has examined different books, publications, internet resources and normative acts in Latvian, English and German languages, as well as the case law of the Supreme Court of the Republic of Latvia. As a result of this Bachelor's thesis research, conclusions and suggestions for establishing, classifying, contesting and substantiating the generally-known fact have been developed