The significance of stemflow chemistry for epiphytic lichen diversity in a dieback-affected spruce forest on Mt Brocken, northern Germany

2002 ◽  
Vol 34 (5) ◽  
pp. 415-427 ◽  
Author(s):  
Markus Hauck ◽  
Volker Hesse ◽  
Michael Runge
Keyword(s):  
Northern Germany ◽  
Epiphytic Lichen ◽  
Forest Dieback ◽  
Lichen Diversity ◽  
Sample Tree ◽  
Dead Trees ◽  
Minor Influence ◽  
Bark Chemistry ◽  
A Minor ◽  
Needle Loss

AbstractEpiphytic lichen diversity in a boggy stand of Norway spruce (Picea abies) was studied in the eastern Harz Mountains, northern Germany. Spruce trees at wet sites were affected by forest dieback, whereas trees on drier sites remained unaffected. Lichen diversity was higher on diebackaffected trees than on healthy ones. The foliose lichen Hypogymnia physodes was significantly more frequent on dead trees, whereas the crustose, extremely toxitolerant Lecanora conizaeoides occurred more frequently on healthy trees. Stemflow concentrations of NH⊂4⊃+, NO⊂3⊃-, PO⊂3⊃-, and SO⊂4⊃2- were lower on affected trees. This is attributed to reduced interception from the atmosphere due to needle loss. Cover of H. physodes decreased with increasing mean SO⊂4⊃2- concentration in stemflow. The total of lichen species per sample tree also decreased with increasing SO⊂4⊃2- concentration in stemflow, indicating that most species reacted in a similar way as H. physodes. Cover of L. conizaeoides increased with increasing SO⊂4⊂2- concentration, but decreased at higher SO⊂4⊃2- concentrations. Bark chemistry had a minor influence on lichen diversity.

Structure-activity relations and β-lactamase resistance

1980 ◽  
Vol 289 (1036) ◽  
pp. 197-205 ◽  
Keyword(s):  
Broad Spectrum ◽  
Product Inhibition ◽  
Sulphur Atom ◽  
Chemical Modifications ◽  
Gram Negative ◽  
Structure Activity ◽  
Broad Spectrum Resistance ◽  
Structure Activity Relations ◽  
Minor Influence ◽  
A Minor

β-Lactam antibiotics resistant to β-lactamase degradation can be produced by many chemical modifications, but often at the expense of antibacterial activity. Substitution onto several positions in the molecule produces different and often selective resistance; for instance, heavily sterically hindered acyl groups give staphylococcal P-lactamase resistance to penicillins, and resistance to some enzymes from Gram-negative pathogens to both penicillins and cephalosporins. 6-α- or 7-α-substituents respectively confer a broad spectrum of resistance (e.g. cefoxitin), but changes at positions 2 or 3 have only a minor influence on enzyme susceptibility. Changes in the ring condensed with the β-lactam, such as changing ceph-3-em to ceph-2-em may greatly enhance stability. Small improvements can occur when the nuclear sulphur atom is oxidized, but a much better effect is obtained when it is replaced by another atom such as oxygen, as in clavulanic acid. This compound appears to have broad spectrum resistance which is actually due to susceptibility and subsequent product inhibition.

Lubrication Properties of Aqueous Solutions with Polyethoxylated Ether (PEOE) Added

2011 ◽  
Vol 239-242 ◽  
pp. 1359-1363
Author(s):  
Chao Hui Zhang ◽  
Si Si Liu ◽  
Yue Tao Sun ◽  
Jun Ming Liu
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Metal Working ◽  
Functional Additives ◽  
Film Forming ◽  
Minor Influence ◽  
Forming Characteristics ◽  
Aqueous Surfactants ◽  
A Minor ◽  
Lubrication Properties

Aqueous solutions have found broad usages as lubricants, in conjunction with other possible utilizations, such as in metal working and other industries. Due to the inferior lubricity, functional additives are needed to improve their tribological performances among which aqueous surfactants are exclusively included. The film forming property of aqueous solution with polyethoxylated ether added (PEOE) is measured, taking consideration of the influences of the temperature and the concentration. The addition of PEOEs into aqueous solutions will largely increase the film forming capacity. But the concentration has only a minor influence on the lubrication property of the aqueous solutions with PEOEs. The cloud point will strongly alter the film forming characteristics.

scholarly journals Influence of Different Commercial Yeasts on Volatile Fraction of Sparkling Wines

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 247
Author(s):  
Valeriu V. Cotea ◽  
Mihai Cristian Focea ◽  
Camelia Elena Luchian ◽  
Lucia Cintia Colibaba ◽  
Elena Cristina Scutarașu ◽  
...  
Keyword(s):  
International Organization ◽  
Volatile Fraction ◽  
Chemical Parameters ◽  
Physical Chemical ◽  
Organoleptic Characteristics ◽  
Mass Spectrometry Technique ◽  
Minor Influence ◽  
Spectrometry Technique ◽  
A Minor ◽  
Aging Stage

The occurrence of aroma constituents in sparkling wines, with direct impact on their organoleptic characteristics, is affected by several factors, for example the base-wine particularities, grapes cultivar conditions, inoculated yeasts, the aging stage, and wine-making practices. This study evaluated the influence of different four commercial yeasts (IOC FIZZ™, IOC DIVINE™, LEVULIA CRISTAL™, and IOC 18-2007™) on the volatile composition of experimental sparkling wines. For this, five sparkling wines variants from the Muscat Ottonel grape variety were obtained. The base-wine was obtained through reverse osmosis and had a predetermined alcoholic concentration (10.5% vol.). In order to fulfill the proposed purpose, the experimental sparkling wines were characterized by the physical–chemical parameters (according to International Organization of Vine and Wine methods of analysis), volatile fraction (using gas-chromatography coupled with mass spectrometry technique), and sensory descriptors. Data showed a key impact on the concentration of the volatile constituents (p < 0.05), depending on the type of inoculated yeast for the second fermentation. Regarding the sensory analysis, important differences can be observed due to the type of inoculated yeast. Only a minor influence on the physical–chemical parameters was registered.

scholarly journals Phytoplankton thermal responses adapt in the absence of hard thermodynamic constraints

2018 ◽  
Author(s):  
Dimitrios - Georgios Kontopoulos ◽  
Erik van Sebille ◽  
Michael Lange ◽  
Gabriel Yvon-Durocher ◽  
Timothy G. Barraclough ◽  
...  
Keyword(s):  
Thermal Performance ◽  
Thermal Sensitivity ◽  
Meta Analysis ◽  
Habitat Type ◽  
Performance Curve ◽  
Thermal Environments ◽  
Thermal Performance Curve ◽  
Performance Curves ◽  
Minor Influence ◽  
A Minor

AbstractTo better predict how populations and communities respond to climatic temperature variation, it is necessary to understand how the shape of the response of fitness-related traits to temperature evolves (the thermal performance curve). Currently, there is disagreement about the extent to which the evolution of thermal performance curves is constrained. One school of thought has argued for the prevalence of thermodynamic constraints through enzyme kinetics, whereas another argues that adaptation can—at least partly—overcome such constraints. To shed further light on this debate, we perform a phylogenetic meta-analysis of the thermal performance curves of growth rate of phytoplankton—a globally important functional group—, controlling for environmental effects (habitat type and thermal regime). We find that thermodynamic constraints have a minor influence on the shape of the curve. In particular, we detect a very weak increase of maximum performance with the temperature at which the curve peaks, suggesting a weak “hotter-is-better” constraint. Also, instead of a constant thermal sensitivity of growth across species, as might be expected from strong constraints, we find that all aspects of the thermal performance curve evolve along the phylogeny. Our results suggest that phytoplankton thermal performance curves adapt to thermal environments largely in the absence of hard thermodynamic constraints.

Meiofauna constitute a considerable portion of invertebrate drift among moss-rich patches within a karst hydrosystem

Biologia ◽  
2014 ◽  
Vol 69 (3) ◽  
Author(s):  
Mirela Perić ◽  
Tvrtko Dražina ◽  
Maria Špoljar ◽  
Ines Radanović ◽  
Biserka Primc ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Spatial Scale ◽  
Early Summer ◽  
Small Scale ◽  
Invertebrate Drift ◽  
Flow Conditions ◽  
Small Spatial Scale ◽  
Minor Influence ◽  
Drift Density ◽  
A Minor

AbstractAiming to establish the most frequent invertebrate taxa in drift at the small spatial scale within a moss-rich karst tufa-precipitating hydrosystem, we sampled drift among microhabitats differing in substratum type and flow conditions along a tufa barrier-cascading lotic reach. Additionally, we addressed the question of the contribution and the potential significance of meiofauna within the overall invertebrate drift at the small spatial scale. During the study period, a total of 60 invertebrate taxa were recorded in the drift. Six of these taxa belonged to the annelid/arthropod meiofauna and they represented 35% of total drift density. Macroinvertebrates found in drift were represented mainly by larval insects. The composition of the most abundant taxa in total drift was as follows: Alona spp. (Cladocera 26.7%), Riolus spp. (Coleoptera: Elmidae 13.2%), Simulium spp. (Diptera: Simuliidae 12.2%), Enchytraeidae (Oligochaeta 10.4%), Hydrachnidia (6.3%), Orthocladinae (Diptera: Chironomidae 3.9%) and Naididae (Oligochaeta 3.6%). Faunal drift densities and amounts of transported particulate matter (PM) were highest at the fast-flowing sites located at the barriers and lowest at the slow-flowing sites within pools. Similarly to the seasonal amounts of transported PM, faunal drift was lowest in winter, and peaked in autumn and in late spring/early summer. Correlation between flow velocity and PM-faunal drift densities suggested a significant effect of the dislodged PM, though a minor influence of discharge and flow velocity on faunal drift. We suggest that the small-scale habitat heterogeneity and the respective feeding and refugial strategies of the fauna, as well as faunal passive dislodgement initiated by the shear forces of the flow were the most important drivers of observed drift patterns.

scholarly journals Perspective determines the production and interpretation of pointing gestures

2020 ◽  
Author(s):  
Oliver Herbort ◽  
Lisa-Marie Krause ◽  
Wilfried Kunde
Keyword(s):  
Virtual Reality ◽  
Virtual Reality Environment ◽  
Observer Perspective ◽  
Minor Influence ◽  
Pointing Gestures ◽  
A Minor ◽  
The Relationship

Abstract Pointing is a ubiquitous means of communication. Nevertheless, observers systematically misinterpret the location indicated by pointers. We examined whether these misunderstandings result from the typically different viewpoints of pointers and observers. Participants either pointed themselves or interpreted points while assuming the pointer’s or a typical observer perspective in a virtual reality environment. The perspective had a strong effect on the relationship between pointing gestures and referents, whereas the task had only a minor influence. This suggests that misunderstandings between pointers and observers primarily result from their typically different viewpoints.

Response of Evernia prunastri to urban environmental conditions in Central Europe after the decrease of air pollution

2013 ◽  
Vol 45 (1) ◽  
pp. 89-100 ◽  
Author(s):  
Anna LACKOVIČOVÁ ◽  
Anna GUTTOVÁ ◽  
Martin BAČKOR ◽  
Peter PIŠÚT ◽  
Ivan PIŠÚT
Keyword(s):  
Air Pollution ◽  
Central Europe ◽  
Photosynthetic Pigments ◽  
Urban Environments ◽  
Physiological Status ◽  
Epiphytic Lichens ◽  
Evernia Prunastri ◽  
Epiphytic Lichen ◽  
Lichen Diversity ◽  
Positive Correlations

AbstractThe epiphytic lichen Evernia prunastri is sensitive to air pollution and reacted by total retreat to the worsening of air quality during the peak of SO2 pollution in Central Europe (1950s–1990). Since 1990, after a significant decrease in air pollution, epiphytic lichens recolonized previously polluted areas, including E. prunastri. We investigated the physiological status of E. prunastri, transplanted for six months in 34 sites in the urban area of Bratislava (Slovakia) under current conditions. The content of chlorophylls, cortical and medullar secondary metabolites and soluble proteins were explored. We then examined the relationship of these parameters with the environmental quality status, reflected by the diversity of epiphytic lichens. The results showed that the physiological status of E. prunastri did not change significantly after exposure. Positive correlations were found between lichen diversity in the sampling sites and physiological parameters (photosynthetic pigments and phaeophytinization quotient) in the transplants. Transplants from sampling sites with a greater proportion of nitrophilous lichens displayed a decrease in photosynthetic pigments. Sites where E. prunastri naturally occurred had a lower proportion of nitrophilous species in comparison to sites where E. prunastri was not present. This suggests that the indicator species E. prunastri may also recolonize sites with low eutrophication in urban environments under decreased air pollution, and the information on its presence can help to assess the pressure caused by nitrogen excess.

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