Recent developments in lake modelling

2005 ◽  
Vol 51 (8) ◽  
pp. 5-12 ◽  
Author(s):  
S.E. Jørgensen
Keyword(s):  
Species Composition ◽  
Thermodynamic Equilibrium ◽  
Structural Changes ◽  
Lake Modelling ◽  
Recent Developments ◽  
And Shifts

The radical variability of ecosystems such as lakes when reacting to prevailing conditions has in many situations found traditional modelling too inflexible. The introduction of eco-exergy, a measure of a system's distance from thermodynamic equilibrium, has enabled models to deal with ecosystems that can show major structural changes resulting from adaptation and shifts in species composition.

scholarly journals Vegetation Diversity of Screes and Taluses of The Pamir and South-Western Tian Shan in Middle Asia

2021 ◽  
Author(s):  
Arkadiusz Nowak ◽  
Sebastian Świerszcz ◽  
Sylwia Nowak ◽  
Marcin Nobis
Keyword(s):  
Species Composition ◽  
Arid Zone ◽  
Field Studies ◽  
Vegetation Diversity ◽  
Plant Associations ◽  
Middle Asia ◽  
Recent Developments ◽  
Phytosociological Relevés ◽  
High Degree ◽  
Tian Shan

AbstractThis paper presents the results of phytosociological research on scree vegetation of the Pamir and south-western Tian Shan. We collected 222 phytosociological relevés during field studies conducted in 2015–2019, applying the Braun-Blanquet approach. We identified 21 plant communities on mobile and stabilized screes of colluvial cones, aprons and fans, inhabiting mainly the montane and alpine belts in several ranges (e.g. Peter the First, Alichur, Shugnan, Shachdarian, Darvaz, Rushan, Vanch, Fergana, Kyrgyz and Terskey ranges). As a result we provide the first comprehensive hierarchical syntaxonomic synopsis of scree communities at montane and alpine elevations in the eastern Middle Asia. The collected vegetation relevés represent the majority of the variation among the phytocoenoses of gravel, pebble, cobble and rock block slides and screes in the montane and alpine belts. As a result of field studies and Twinspan analyses, nine associations were identified on screes of the Pamir and western Tian Shan. All these communities were assigned to the Sileno brahuicae-Lactucetalia orientalis Nowak et al. 2021. Additionally, within the nitrophilous compact gravel screes one subassociation of Corydalidetum kashgaricae trigonelletosum gontscharovii was distinguished. In the most arid zone two additional plant associations and one subassociation were identified in gravelly semi-deserts zone. The main factors determining the species composition of the studied associations are scree mobility, rock particle size, elevation above sea level and slope inclination. Our research revealed considerable diversity of scree habitats of montane and alpine belts what might be astonishing regarding harsh environment of this mountainous territory. However, a great number of lineages that evolved here and particularly rich species pool of this habitat in Middle Asia facilitate remarkable diversity among vegetation of taluses and screes. The distinctiveness of species composition is additionally enhanced by high degree of endemism of chasmophytic habitats in the eastern part of Middle Asia. Despite recent developments, the prominent chasmophytic vegetation of Middle Asia still needs thorough studies focused on its relationship to semi-desert, tall-forb and petrophytic communities of high mountains of the Pamir, Hindu-Kush, Kunlun and Central Tian Shan.

scholarly journals Diversity of Algae and Cyanobacteria and Bioindication Characteristics of the Alpine Lake Nesamovyte (Eastern Carpathians, Ukraine) from 100 Years Ago to the Present

Diversity ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 256
Author(s):  
Petro M. Tsarenko ◽  
Olena P. Bilous ◽  
Olha M. Kryvosheia-Zakharova ◽  
Halyna H. Lilitska ◽  
Sophia Barinova
Keyword(s):  
Species Composition ◽  
Structural Changes ◽  
Algal Species ◽  
Taxonomic Composition ◽  
Alpine Lake ◽  
Algal Flora ◽  
Ecological Analysis ◽  
Modern Species ◽  
Eastern Carpathians ◽  
Infraspecific Taxa

The species diversity and changes in the structural dynamics of the algal flora from the alpine lake Nesamovyte has been studied for 100 years. During the period of investigations, 234 species (245 infraspecific taxa) were revealed to cover more than 70% of the modern species composition of the studied lake. The modern biodiversity of algae is characterized by an increase in the number of widespread forms, a change from the baseline “montane” complex in comparison to the beginning of the 20th century. Nevertheless, the Nesamovyte Lake still has a unique algae composition that is typical for high-mountainous European lakes. The presence of a different complex of conventionally arctic species of algae, in particular, diatoms is discussed. Structural changes in the taxonomic composition of the algal flora of the lake as well as in the complex of the leading genera, species and their diversity are revealed. An ecological analysis of the algal species composition of the lake showed vulnerability and degradation to the ecosystem of the lake. On this basis, the issue regarding the question of protection and preservation of the algae significance and uniqueness of the flora of algae in the Nesamovyte Lake are discussed.

Development of Forest Shelterbelts Considering Statistical Forecasts Modelling of Local Weather

2021 ◽  
Vol 18 (1) ◽  
pp. 7-14
Author(s):  
Irina Volkova ◽  
Kseniia Pitulko ◽  
Anzhelika Sergeeva ◽  
Saida Pshidatok
Keyword(s):  
Species Composition ◽  
Tree Species ◽  
Structural Changes ◽  
Moscow Oblast ◽  
Phytopathogenic Bacteria ◽  
Heat Damage ◽  
Class 1 ◽  
Local Weather ◽  
Species Class

This work aims to study the effect of high temperatures and phytopathogenic bacteria on different types of trees in the forest shelterbelts. Therefore, in 2018, 17 tree species were studied from 50 sample sites in the Moscow oblast (Russia). Leaf scorching, diseases caused by phytopathogenic bacteria, and heat damage to the crowns were examined in 5224 tree species. Based on the degree of crown damage, the studied tree species were divided into four classes. It was found that the heat damage to tree crowns was identical between the three sampling aspects (correlation coefficient 0.99). The plant species composition must be considered when developing forest shelterbelts. A long-term forecast on structural changes of planted areas is possible, considering the species composition and climatic characteristics of the region. Class 5 includes only chestnut; class 4 includes three species; class 3 is represented by seven species. Class 2, includes six species, and is the most suitable in developing forest plantations. No tree species in class 1 were found (trees with no damage). There is a connection between pathologies and heat injuries in trees from classes 4 to 5 (correlation 0.89).

scholarly journals Scalable Preparation of Enantioenriched (S)-5-methylhept-2-en-4-one. Synthesis and Aroma Properties of Achiral Analogues Thereof

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4497
Author(s):  
Eva Puchľová ◽  
Michal Dendys ◽  
Ivan Špánik ◽  
Peter Szolcsányi
Keyword(s):  
Natural Product ◽  
Title Compound ◽  
Structural Changes ◽  
Chemoenzymatic Synthesis ◽  
Synthetic Analogues ◽  
Purification Method ◽  
Flavour Compound ◽  
Sensory Analyses ◽  
And Shifts

(S)-5-Methylhept-2-en-4-one is a key flavour compound in hazelnuts. We have performed its chiral-pool-based chemoenzymatic synthesis with 39% overall yield (73% ee). The four-step aldol-based sequence avoids the use of highly reactive and/or toxic reagents, does not require anhydrous conditions and uses only distillation as the purification method. Thus, such methodology represents a green and scalable alternative to only two stereoselective approaches towards this natural product known so far. In addition, we have designed and prepared a set of new (di)enones as achiral synthetic analogues of the title compound. The results of their sensory analyses clearly show that relatively minor structural changes of the natural molecule significantly alter its olfactory properties. Thus, simple (poly)methylation completely changes the original hazelnut aroma of (S)-5-methylhept-2-en-4-one and shifts the odour of its analogues to eucalyptus, menthol, camphor, and sweet aroma.

New microcrystalline catalysts

1990 ◽  
Vol 333 (1629) ◽  
pp. 173-207 ◽  
Keyword(s):  
Solid State ◽  
Active Sites ◽  
Structural Changes ◽  
Specific Reference ◽  
Solid State Physics ◽  
Solid Oxides ◽  
Molecular Dimension ◽  
Combined Use ◽  
Recent Developments ◽  
And Performance

Owing to recent developments there is now a prodigality of crystalline inorganic solids capable of catalysing the chemical conversions of numerous gaseous molecules, especially hydrocarbons. Very many of these new catalysts are microporous and microcrystalline, and have their accessible active sites distributed uniformly throughout their bulk. They are, therefore, amenable to investigation by essentially all of the premier experimental and computational tools of solid-state physics and solid-state chemistry. The deployment of these tools has yielded fresh insights into the mechanisms of catalytic action and also suggested new strategies, some of which have already been tested, for the design of specially tailored selective catalysts. The benefits of multi-pronged approaches to the investigation of the reactivity of catalysts, made possible by the combined use of intense X -ray sources (both laboratory-based and synchrotron radiation) and supercomputers, are illustrated by specific reference to zeolitic solids that contain cages and channels of molecular dimension. Such crystalline solids, either in their highly acidic or metal-ionexchanged forms, are of great practical value on an industrial scale. They are also ideally suited for in situ exploration of the subtle structural changes that accompany, or are responsible for, the activation and deactivation of catalysts. Ways of optimizing the performance of catalysts, including the possible construction of ‘teabag’ analogues, and of coping computationally with their properties and performance so as to deepen our understanding of their mode of operation are outlined with reference to both the zeolites and the ever-widening range of solid oxides crystallizing with pyrochlore and perovskite structures.

Vegetation change in an urban grassy woodland 1974 - 2000

2004 ◽  
Vol 52 (5) ◽  
pp. 597 ◽  
Author(s):  
J. B. Kirkpatrick
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Exotic Species ◽  
Native Species ◽  
Vegetation Change ◽  
Structural Changes ◽  
Linear Models ◽  
Tree Cover ◽  
Native Plant ◽  
Native Species Richness

Few temporal studies document vegetation change in Australian temperate grassy woodlands. Floristic and structural data were collected from 68 randomly located sites in the Queens Domain, an urban grassy woodland remnant, in 1974, 1984, 1994 and 2000 and a search made for rare species. Species of conservation significance were concentrated at highly disturbed sites, whereas vegetation types of conservation significance decreased in area as a result of increases in the numbers of Allocasuarina verticillata, which caused a change in many unmown areas from Eucalyptus viminalis grassy woodland to E. viminalis–A. verticillata woodland/forest or A. verticillata open/closed forest. Structural changes were associated with changes in species composition and an increase in native-species richness. Increases in tree cover occurred where fires were most frequent, possibly as a result of the lack of mammalian herbivores. The frequencies of herbs and annual grasses were strongly affected by precipitation in the month of sampling. Half of the species that showed a consistent rise or fall through time were woody plants, approximately twice the number expected. In the dataset as a whole, species-richness variables were largely explained by varying combinations of variables related to moisture availability, altitude and the incidence of mowing. The strongest influences on species composition were the same, although slope and time since the last fire also contributed to multiple regression and generalised linear models. Compositional stability was positively related to native-species richness, whereas high levels of exotic-species richness occurred at both low and high levels of native-species richness. The maintenance of native-plant biodiversity on the Domain requires such counterintuitive measures as the maintenance of exotic trees and the control of native trees, demonstrating the contingencies of conservation management in fragmented vegetation that consists of a mixture of native and exotic species.

Structural changes in protected forests in Sweden: implications for conservation functionality

2015 ◽  
Vol 45 (9) ◽  
pp. 1215-1224 ◽  
Author(s):  
Per-Ola Hedwall ◽  
Grzegorz Mikusiński
Keyword(s):  
Species Composition ◽  
Tree Species ◽  
Structural Changes ◽  
Fire Suppression ◽  
National Forest Inventory ◽  
Active Management ◽  
Tree Species Composition ◽  
Small Areas ◽  
Large Trees

Protected forest areas (PFAs) are key features of biodiversity conservation, and knowledge about long-term development is crucial in evaluating their efficiency and management needs. Longitudinal data on forest structure in PFAs is uncommon and often from small areas. Here we use data from the Swedish National Forest Inventory to study changes in more than 750 000 ha of PFAs over 60 years. Structures important for biodiversity, e.g., number of large trees and the volume of hard deadwood, including both standing and down wood, have more than doubled. The initial volume of deadwood, however, was very low. The overall tree species composition was stable over time, and only among the largest trees were there indications of a shift towards the late successional Norway spruce (Picea abies (L.) Karst.). Deadwood increased independent of species, size of wood, and site characteristics. This increase was positively related to the volume of living trees and forest age. We conclude that Swedish PFAs, in the absence of active management and under fire suppression at the landscape scale, develop structural components that are crucial for conservation of biodiversity. However, although tree species composition appears stable, present disturbance regimes in the PFAs are considerably different from those in naturally dynamic forests, which may have implications for long-term biodiversity maintenance.

scholarly journals The application of ATR-FTIR Spectroscopy and the Reversible DNA Conformation as a Sensor to Test the Effectiveness of Platinum(II) Anticancer Drugs

2018 ◽  
Author(s):  
Khansa Al-Jorani ◽  
Anja Rüther ◽  
Miguela Martin ◽  
Rukshani Haputhanthri ◽  
Glen B. Deacon ◽  
...  
Keyword(s):  
Ftir Spectroscopy ◽  
Cancer Cells ◽  
Structural Changes ◽  
Isotonic Saline ◽  
Platinum Complexes ◽  
Attenuated Total Reflection ◽  
Dna Conformation ◽  
Acetone Water ◽  
Intensity Changes ◽  
And Shifts

Platinum(II) complexes have been found to be effective against cancer cells. Cisplatin curbs cell replication by interacting with the deoxyribonucleic acid (DNA), eventually leading to cell death and reducing cell proliferation. In order to investigate the ability of platinum complexes to affect cancer cells, two examples from the class of polyflurophenylorganoamidoplatinum(II) complexes were synthesised and tested on isolated DNA. The two compounds trans-[N,N’-bis(1,2,3,5,6-pentafluorophenyl)ethane-1,2-diaminato(1-)](2,3,4,5,6-pentafluorobenzoato)(pyridine)platinum(II) (PFB), and trans-[N,N’-bis(1,2,3,5,6-pentafluorophenyl)ethane-1,2-diaminato(1-)](2,4,6-trimethylbenzoato)(pyridine)platinum(II) (TMB) were compared with cisplatin through their reaction with DNA. Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectroscopy was applied to analyse the interaction of the Pt(II) complexes with DNA in the hydrated, dehydrated and rehydrated state. These were compared with control DNA in acetone/water (PFB, TMB) and isotonic saline (cisplatin) under the same conditions. Principle Component Analysis (PCA) was applied to compare the ATR-FTIR spectra of the untreated control DNA with spectra of PFB and TMB treated DNA samples. Disruptions in the conformation of DNA treated with the Pt(II) complexes upon rehydration were mainly observed by monitoring the position of the IR-band around 1711 cm-1 assigned to the DNA base-stacking vibration. Furthermore, other intensity changes in the phosphodiester bands of DNA at ~1234 cm-1 and 1225 cm-1 and shifts in the dianionic phosphodiester vibration at 966 cm-1 were observed. The isolated double stranded DNA (dsDNA) or single stranded DNA (ssDNA) showed different structural changes when incubated with the studied compounds. PCA confirmed PFB had the most dramatic effect by denaturing both dsDNA and ssDNA. Both compounds, along with cisplatin, induced changes in DNA bands at 1711, 1088, 1051 and 966 cm-1 indicative of DNA conformation changes. The ability to monitor conformational change with infrared spectroscopy paves the way for a sensor to screen for new anticancer therapeutic agents.

scholarly journals RETHINKING WORKFORCE DIVERSITY RESEARCH THROUGH CRITICAL PERSPECTIVES: EMERGING PATTERNS AND RESEARCH AGENDA

2018 ◽  
Vol 6 (3) ◽  
pp. 650-670 ◽  
Author(s):  
Erhan AYDIN ◽  
Emir ÖZEREN
Keyword(s):  
Diversity Management ◽  
Point Of View ◽  
Theoretical Development ◽  
Workforce Diversity ◽  
Holistic View ◽  
Conceptual Clarity ◽  
Recent Developments ◽  
Current Article ◽  
And Shifts ◽  
Diversity Research

This paper aims at highlighting the theoretical development of diversity management by providing an integrated understanding of how diversity management has made progress and evolved in organisations. The current article adopts a conceptual and critical review to demonstrate the changes and shifts in diversity management research. This study reveals that there are four stages of workforce diversity within the business and management field. These stages are equal employment opportunity/affirmative action, valuing differences, diversity management and global diversity management. Each stage is discussed in greater details within the article. This study contributes to the broader diversity management literature in three main ways: firstly, by shedding some light on the conceptual clarity of the diversity notion itself; secondly, by foregrounding the holistic view of diversity management; thirdly, by reflecting the recent developments in diversity research. The review consistently points to the fact that the current literature on diversity management has been predominantly shaped by a mainstream managerial discourse and neoliberal logic which has mostly a discrimination focus rather than an inclusiveness perspective. The paper also suggests that further research is required on workforce diversity particularly with an emic, an intersectional, a contextual and a relational approach rather than reproducing the existing knowledge by an etic framing of diversity from an instrumental point of view that dominates the extant literature.

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