This text is a critical interpretation of Walter Benjamin’s theory in the context of the contemporary situation in art and culture. Benjamin’s innovative method of analysis and key concepts in art ...theory and their simultaneous research and political function are carefully reconstructed. This critical analysis is centered on the main concept of Benjamin’s philosophical aesthetics, the concept of ‘aura’. This analysis shows how Benjamin mixes and replaces the aura of the work of art with the aura of the historical object. Benjamin’s main thesis about the loss of the aura of the work of art in the age of its technical reproducibility is disputed. Technical reproducibility does not take away the aura of the work of art, but separates its aura from the aura of the historical object. Auraticness is inherent in every work insofar as it is a work of art. The aura of the historical object does not disappear in modernity either. With the emergence of historical and aesthetic consciousness, of the historical and art museum, the almost mechanical production of auratic objects began in modernity. As a result of the critical analysis of the concept of “aura”, the main binary oppositions that frame Benjamin’s theory of art—art with aura/art without aura; art with cult value/art without cult value; aestheticization of politics/politicization of art—are questioned. At the end of this text, the key lines of analysis proposed by Benjamin in an attempt to make sense of the radical changes in art since the beginning of the 20th century are used to outline the contemporary situation in art and the changes in perception with which it is associated.
Purpose
Two major developments have taken place in the agri-food industry in recent decades. First, valorization of the plant by-products can contribute significantly for ensuring sustainability, ...especially applying green technologies for recovery of bio- and/or techno-functional compounds. Second, substitution of synthetic food additives, particularly colorants, by their natural counterparts is of utmost importance to meet consumer demands. The aim of this study was to evaluate a new process for green extraction of polyphenols from
Crocus sativus
tepals, the primary by-product of saffron spice production.
Methods
A new strategy for recovery of polyphenols from saffron tepals was studied. An extraction process combining two subcritical water extractions steps with enzymatic treatment incorporated between them was established on a pilot scale. Liquid chromatography–mass spectrometry was used for polyphenols profile characterisation. The co-pigmentation efficiency of the polyphenol extract and its effect on thermal stability of strawberry anthocyanins were evaluated in model solutions.
Results
An approximately fourfold increase in the polyphenolic yield was achieved with the new combined extraction method. 16 flavonoids, mainly flavonols, were detected in the saffron tepal extract. To the best of our knowledge, the presence of the flavone apigenin has not been described before in
Crocus sativus
. The addition of saffron tepal polyphenols, acting as co-pigments, significantly reduced the thermal degradation of strawberry anthocyanins.
Conclusion
The obtained results demonstrate an innovative approach for the valorisation of saffron tepals through potential application of the by-product polyphenols in fruit processing.
Graphical Abstract
Aldrovanda vesiculosa is an endangered aquatic species in Romania which grows in shallow waters where competition with other aquatic species is limited or absent. A comprehensive overview of the ...species? distribution and habitat preferences in Romania is currently lacking. In this context, this study aimed to update the distribution and habitat preferences of the species. Localities from Dobrogea, Oltenia, Muntenia, Transylvania, and Cri?ana represented the study areas. For the vegetation classification, 71 releves with A. vesiculosa were analysed. The size of the sample areas ranged from 4 m2 to 25 m2. Vegetation syntaxonomic assignment was performed by agglomerative hierarchical clustering. The optimal number of clusters was chosen using the corrected Rand and Silhouette indices. Diagnostic species were identified for each cluster based on the indicator value index (IndVal). The study results showed that the dominant majority of the previous populations of A. vesiculosa (89%) were no longer identified from Romania in the 2008?2021 period. Recently (2021?2023), they were found only in six localities in the Dobrogea, Transylvania, and Oltenia regions. The causes of the disappearance of the species are eutrophication and the lowering of the water level. From a phytocoenological point of view, 11 plant communities were identified where A. vesiculosa is found. According to the EUNIS classification, this species inhabits wetlands (Q) and inland surface waters (C). In conclusion, translocation is suggested as the primary conservation measure for protecting the species.
Aim
To analyse the biogeographic patterns of Temperate Deciduous Forests (TDFs) in Western Eurasia based on different life‐forms and forests layers and explore their relationships with the current ...climate, Last Glacial Maximum (LGM) climate and topography.
Location
Western Eurasia.
Taxon
Vascular plants.
Methods
We delimited nine regions encompassing the variability of TDFs in Western Eurasia and collected 1000 vegetation plots from each. We deconstructed the plant communities into three layers, tree, shrub and floor. We used (i) generalized linear mixed models (GLMM) to analyse the influence of current climate, historical climate and topography on species richness by accounting for regional effects and (ii) redundancy analysis (RDA) with variance partitioning to describe the variation in life forms along abiotic gradients. The three forest layers were analysed jointly and separately.
Results
The Balkans, Alps and Carpathians appeared to be the richest in plant species, whereas the British Isles and the Hyrcanian region were the poorest. Annual temperature range and annual mean temperature were the best predictors of species richness for the whole dataset and for the shrub layer. The tree layer richness was mainly explained by the annual temperature range and by elevation, whereas the forest floor richness was more related to the annual temperature range and the annual mean temperature differences between the LGM and current climate. The current climate was the main predictor of the composition of the whole community, the tree layer and the floor layer, while the shrub layer was also influenced by historical climate.
Main conclusions
Our overview of the diversity of temperate deciduous forests in Western Eurasia demonstrates different patterns and drivers across life‐forms and forest layers. While the diversity of trees is mainly linked to current climatic conditions, the shrub layer is also driven by postglacial‐glacial climatic stability, suggesting a different origin from forest trees.
Question: What are the woody vegetation encroachment patterns after agricultural land abandonment? Focusing on two parameters, woody plant species richness and vertical vegetation heterogeneity ...(number of different vegetation strata and their relative cover) we investigated: (a) the effect of forest encroachment following land abandonment; (b) the comparative importance of forest encroachment vis-a-vis top-ographic and climatic parameters, and finally: (c) the ecological importance of eight land-cover types encountered in abandoned agricultural landscapes. Location: The Balkan Peninsula (Albania, Bulgaria, Croatia, Greece). Methods: We set up a standard methodology for 1 × 1 km site selection (70 sites) and data collection within 497 plots, along a well-defined forest encroachment gradient that reflects land abandonment in terms of woody vegetation cover. Results: The pattern that emerged was neither clear nor common for the Balkan region, regarding the effect of forest encroachment on the woody plant species richness in young forests, formed from 20 to 50 years after land abandonment. However, at national level, species diversity was significantly affected by elevation (Bulgaria and Croatia) and temperature (Croatia), with lower and cooler areas being richer. Elevation was of great importance in determining vertical vegetation heterogeneity. Woodlots, broad-leaved forests, hedges and shrublands held the highest woody species richness in comparison to the more open land-cover types, and vertical vegetation heterogeneity was higher in open forests and woodlots. Conclusions: We expect the expansion of broad-leaved forests following land abandonment to enhance woody species richness. However, other land-cover types that were found to be important for woody plants should be maintained. As woody plants play a key role in supporting overall biodiversity, by providing suitable habitat for many species, we consider the preservation of a mosaic of patches of different landcover types essential for the conservation of both plant and animal species diversity. Young forests should be preserved at intermediate stages of succession, through intermediate disturbance activities, including medium intensity grazing and the enhancement of wild ungulates.
The influence of screws with and without propeller, as well as the independent variables of material moisture content, working screw speed, feeding screw speed and die temperature on the changes of ...some physical and mechanical properties during singles-screw extrusion of rice semolina was studied. The response surface methodology was used with an orthogonal central composite design. Optimum modes of operation which lead to the maximization of the mass flow rate and the sectional expansion index and the minimization of the specific mechanical energy were established. The obtained results show that the use of a propeller in single-screw extrusion leads to an increase in extruder mass flow rate, a decrease in the specific mechanical energy and an increase in the sectional expansion index.
•Estimating missing Ellenberg Indicator Values (EIV) could help plant ecology studies.•We tested and compared several methods for estimating missing EIV from existing data.•Multiple Linear Regression ...and k-Nearest Neighbour performed better than the others.•Statistical methods are more effective than imputation based on expert knowledge.•This approach would greatly facilitate monitoring species with unknown EIV.
Ellenberg indicator values (EIV) are widely used in vegetation ecology, but the values for many species in Southeastern Europe are not available due to incomplete knowledge of their ecology: it is therefore of paramount importance to estimate missing values in existing databases. The entire EIV set for a single species can be missing or a single EIV can be missing for species for which other indicator values are available. Our aim here is to provide a simple method to impute missing values for species who have missing data in a single or multiple EIV. For this purpose, we adopt a multiple imputation procedure and compare a number of imputation methods on the basis of two datasets: i) “indices”, the set of 9 Ellenberg indicators taken from literature, available for 10,824 species and ii) “vegetation”, a set describing the physical and climatic characteristics (Light, Temperature, Continentality, Soil moisture, Nitrogen, Soil pH, Hemeroby index, Humidity, Organic_matter) of 29,935 relevés from Southeastern Europe where at least one tree species is present. The imputation methods we considered are: k-Nearest Neighbour, multiple linear regression (with or without collinearity correction), Reprediction Algorithm, Weighted Averaging (WA) and Weighted Averaging Partial Least Squares (WAPLS) regression. The different methods of imputation were compared by looking at the output produced and its deviation from the “true” observed values for a set of species with known EIVs. We have considered a set of species with known EIVs and proceeded to multiple imputation using the methods above; as a measure of performance we adopted the mean squared error (MSE) estimate, and expert judgement of ecological consistency. Models based on Regression and k-Nearest Neighbour seem to outperform the others. On the contrary, Reprediction algorithm in its different forms: produced less satisfactory results.
Imputation of missing values is generally based on expert knowledge or on some variant of weighted averaging (also known as Hill’s method). Here we show that other methods may be more effective and should be appropriately considered by vegetation scientists, since those may allow the application of EIVs in other biogeographic regions.
The present investigation aims to uncover the landscape diversity in Dragoman Municipality, as well as the ecosystem types, which are representative for the territory. The interest towards this ...geographical area roots in its close proximity to the capital city of Sofia and the ongoing road works for the establishment of the “Europe” Motorway. It also represents a continuation of the study of the landscapes and ecosystem types in western direction. The mapping of the landscapes is based on the application of LANMAP 2 approach and the development of several GIS layers, consisting of main landscape components: lithology, relief, climate, soils and land cover. The ecosystem types are differentiated, based on the integration between CORINE Land Cover Dataset as of 2018 and the MAES Typology. The results are showing a final landscape map, consisting of 199 landscapes, representing by code symbols, as well as a map of seven different ecosystem types.
This work represents the first study of the floristic diversity on Bulgaria's ancient mounds. The objective of this research was to assess the importance of the mounds for the preservation of the ...native vascular and cryptogam flora. Our sampling design included 111 ancient mounds distributed throughout the country. We recorded a total of 1059 vascular plants, 58 bryophytes and 61 lichen taxa. Despite their small area, the mounds were shown to preserve nearly a quarter of the Bulgarian flora. The vegetation cover on the mounds included 61% perennials indicating a long-term persistence and stability. The majority (98%) of the established vascular plants were native species. Although the conservation significance of the vascular plant species were not common, we recorded 2 critically endangered, 9 endangered and 14 Balkan endemics during the present study. The lichen
was recorded for the first time in Bulgaria and a new locality of the rare bryophyte
was discovered. The established compositional difference between plots from the northern and southern slopes of the mounds (88.95%) is a testament to the high local habitat diversity. The prevalence of species characteristic for
suggests that the mounds preserve fragments of native grasslands and steppes. The variation in cover of agricultural and other human modified areas in the mounds' immediate surroundings did not substantially affect their species richness. We argue that the ancient mounds should be taken into consideration in future green space planning.
The importance of environmental difference among sites and dispersal limitations of species to the explanation of diversity differs among biological systems and geographical regions. We hypothesized ...that climate and then dispersal limitation will predominantly explain the similarity of alpine vegetation at increasing distances between pairs of regions at subcontinental extent. We computed the similarity of all pairs of 23 European mountain regions below 50° N after dividing the species lists of each region by calcareous or siliceous substrates. Distance decay in similarity was better fitted by a cubic polynomial than a negative exponential function, and the fit was better on calcareous than on siliceous substrate. Commonality analysis revealed that the proportion of explanation of beta diversity by climatic difference had unimodal patterns on a gradient of increasing distance between regions, while explanation by dispersal limitation had consistently rising patterns on both substrates. On siliceous substrate, dispersal limitation explained more of the variation in beta diversity only at longer distances, but it was predominant at all distances on calcareous substrate. The steeper response to distance at <1600 km and >2600 km may indicate dispersal limitation at different temporal scales, and the uptick in the response to distance at the longest distances may reflect how isolated some regions have been before and since the last glacial maximum.
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