1,720,975 research outputs found
Ya'ar Bar'am-An old Quercus calliprinos forest of high nature conservation value in the Mediterranean region of Israel
No full textSclerophyllous oak forests are an important ecosystem type of the natural vegetation in the Mediterranean region. As a part of the mosaic-like landscape, old-growth oak forests, in particular, provide a wide range of ecosystem functions and services. However, due to the general scarcity of older forests in the Mediterranean region, studies on structure and dynamics of oak forests are mostly restricted to younger stands. The aim of this study was to analyze stand structure, dead wood, and natural regeneration of an old Quercus calliprinos forest in northern Israel (nature reserve Ya'ar Bar'am) and to compare the results with those reported from other evergreen Mediterranean oak forests. The mean density of trees was 735 ha(-1), and the mean basal area amounted to 25.0 m ha(-1). The mean tree height was 6.6 m, and the maximum tree height was 13.2 m. The mean dead wood volume was 11 m(3) ha(-1). The sapling density ranged from 1,050 to 6,250 ha(-1). We conclude that Bar'am Forest is of great value for conservation biology. Moreover, this nature reserve has the potential to be a reference for ageing oak stands in current discussions on sustainable forest management
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
Plant Community of the Year 2023: Vegetation of amphibious plants in nutrient-poor waters (Littorelletea uniflorae p.p.)
No full textUm Themen des Schutzes von Pflanzengemeinschaften und ihrer Lebensräume wirksamer in der breiten Öffentlichkeit zu kommunizieren, wird seit 2019 von der Floristisch-Soziologischen Arbeitsgemeinschaft (FlorSoz) die „Pflanzengesellschaft des Jahres“ ausgerufen und ein erläuternder Text veröffentlicht.
Damit sollen politische und administrative Entscheidungs- und Umsetzungsprozesse zur Erhaltung der Vielfalt von Ökosystemen und Pflanzengesellschaften in Deutschland gezielt unterstützt werden.
Für das Jahr 2023 wurde die amphibische Vegetation oligotropher Flachgewässer (Strandlings-Gesellschaften; Littorelletea uniflorae p.p.) ausgewählt. Sie gehören zu den durch Eutrophierung, Flächenrückgang und Klimawandel besonders bedrohten Pflanzengesellschaften Deutschlands.
Es sind deshalb dringend Maßnahmen zum Schutz und zur Wiederherstellung notwendig.
Dieser Artikel gibt einen kurzen Überblick zur naturschutzfachlichen Bedeutung von Strandlingsrasen, zu ihrer floristisch-soziologischen Erforschung und Gliederung, zu ihrer Ökologie sowie zu Ursachen ihres Rückgangs und geeigneten Erhaltungsmaßnahmen.In order to communicate issues relating to the protection of plant communities and their habitats more effectively to the general public, the Floristisch-Soziologische Arbeitsgemeinschaft (FlorSoz) has proclaimed a “Plant Community of the Year” since 2019 and an explanatory text is published.
This is intended to point out communities that are critically endangered, to provide targeted support for political and administrative decision-making and implementation processes for the conservation of the diversity of ecosystems and plant communities in Germany.
For the year 2023, the vegetation of amphibious plants in nutrient-poor lowland waters (Littorelletea uniflorae p.p.) has been selected. Such vegetation of Littorella and related plant communities is threatened with extinction in Germany due to eutrophication, habitat loss and climate change. Protection and restoration measures are therefore urgently needed.
This article provides a brief overview of the conservation significance of the
Littorelletea vegetation, their floristic-sociological characteristics, main drivers for their decline and suitable countermeasures
Does Forest Continuity Enhance the Resilience of Trees to Environmental Change?
No full textThere is ample evidence that continuously existing forests and afforestations on previously agricultural land differ with regard to ecosystem functions and services such as carbon sequestration, nutrient cycling and biodiversity. However, no studies have so far been conducted on possible long-term (>100 years) impacts on tree growth caused by differences in the ecological continuity of forest stands. In the present study we analysed the variation in tree-ring width of sessile oak (Quercus petraea (Matt.) Liebl.) trees (mean age 115-136 years) due to different land-use histories (continuously existing forests, afforestations both on arable land and on heathland). We also analysed the relation of growth patterns to soil nutrient stores and to climatic parameters (temperature, precipitation). Tree rings formed between 1896 and 2005 were widest in trees afforested on arable land. This can be attributed to higher nitrogen and phosphorous availability and indicates that former fertilisation may continue to affect the nutritional status of forest soils for more than one century after those activities have ceased. Moreover, these trees responded more strongly to environmental changes - as shown by a higher mean sensitivity of the tree-ring widths - than trees of continuously existing forests. However, the impact of climatic parameters on the variability in tree-ring width was generally small, but trees on former arable land showed the highest susceptibility to annually changing climatic conditions. We assume that incompletely developed humus horizons as well as differences in the edaphon are responsible for the more sensitive response of oak trees of recent forests (former arable land and former heathland) to variation in environmental conditions. We conclude that forests characterised by a long ecological continuity may be better adapted to global change than recent forest ecosystems
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
- …
