277 research outputs found
Reintroduced, but not accepted: Stakeholder perceptions of beavers in Germany
1. While reintroductions of regionally extinct native species usually benefit ecosystems, reintroduced animals often struggle to locate appropriate habitats where they can establish themselves without conflict with humans. European beavers (Castor fiber) were successfully reintroduced to Germany almost 60 years ago and have reached high abundances again. As beavers can damage trees and change landscapes, they are increasingly in conflict with humans.
2. We investigated human perceptions of beavers in Germany using an online survey, as they are an example of a reintroduced species with an expanding population and potential conflicts with humans. We asked participants about their emotions (anger, fear, interest, joy) towards beavers and what they consider to be acceptable beaver habitats.
3. Of nearly 1500 survey participants, 803 (53%) were from the general public, 475 (32%) from the agricultural sector and 219 (15%) from forestry. People in these sectors had very different perspectives: beavers were positively perceived by the general public, but negatively by stakeholders working in agriculture and forestry. Independently of stakeholder groups, we also found regional differences, as participants from Bavaria—the German state with the highest beaver densities—viewed beavers more negatively than those from the rest of Germany.
4. Zoos and wildlife parks, as well as urban and nature conservation areas, were considered to be the most acceptable habitats for beavers, whereas survey participants did not accept private gardens and cultivated areas as beaver habitats.
5. We discuss the sources of negative emotions towards beavers and how ecologically suitable habitats differ from those that appear acceptable by humans. Even 60 years after their reintroduction, beavers in Germany are still being recognized as both a novelty and a nuisance. Our findings highlight the need for active beaver management and increased public engagement to enable positive coexistence between beavers and humans in Germany
Red Deer Browsing Decelerates Shrub Regrowth Despite Increasing Wolf Presence
Semi-natural open habitats in Europe have been shaped by traditional land use practices, such as extensive mowing or livestock grazing. However, socio-economic transformations have led to the abandonment of many grassland and heathland areas and conservation management is now required to maintain these biodiverse habitats. Grazing by wild red deer (Cervus elaphus) can be a convenient alternative to laborious mechanical management or livestock grazing. Yet it remains unclear if free-ranging ungulates can counteract shrub growth sufficiently to maintain open habitats—especially with natural predators, i.e. wolves (Canis lupus), recolonizing Europe. To assess red deer effects on shrub regrowth after clearance, we installed a cohort of open and fenced plots (17 pairs) in 2016, when wolf presence in our study area (Grafenwöhr military training area, DE) was negligible. When wolf presence had become frequent in 2020, we set up a second cohort (41 paired plots). For both cohorts, the vegetation in the shrub and herb layer was significantly higher in fenced than open plots already after one year. Shrub height increased continuously and dead herbaceous biomass accumulated under red deer exclusion. Consequently, wild red deer can slow down shrub succession in open habitats even under increasing predation pressure. Regardless of wolf presence, a wildlife management that enables red deer to forage in open landscapes could thus reduce the required frequency of conservation management interventions
Dual-color fluorescence cross-correlation spectroscopy to study protein-protein interaction and protein dynamics in live cells
We present a protocol and workflow to perform live cell dual-color fluorescence cross-correlation spectroscopy (FCCS) combined with Förster Resonance Energy transfer (FRET) to study membrane receptor dynamics in live cells using modern fluorescence labeling techniques. In dual-color FCCS, where the fluctuations in fluorescence intensity represent the dynamic "fingerprint" of the respective fluorescent biomolecule, we can probe co-diffusion or binding of the receptors. FRET, with its high sensitivity to molecular distances, serves as a well-known "nanoruler" to monitor intramolecular changes. Taken together, conformational changes and key parameters such as local receptor concentrations and mobility constants become accessible in cellular settings. Quantitative fluorescence approaches are challenging in cells due to high noise levels and the vulnerability of the sample. Here we show how to perform this experiment, including the calibration steps using dual-color labeled β2-adrenergic receptor (β2AR) labeled with eGFP and SNAP-tag-TAMRA. A step-by-step data analysis procedure is provided using open-source software and templates that are easy to customize. Our guideline enables researchers to unravel molecular interactions of biomolecules in live cells in situ with high reliability despite the limited signal-to-noise levels in live cell experiments. The operational window of FRET and particularly FCCS at low concentrations allows quantitative analysis at near-physiological conditions
Integrating movement ecology with biodiversity research - exploring new avenues to address spatiotemporal biodiversity dynamics
Movement of organisms is one of the key mechanisms shaping biodiversity, e.g. the distribution of genes, individuals and species in space and time. Recent technological and conceptual advances have improved our ability to assess the causes and consequences of individual movement, and led to the emergence of the new field of ‘movement ecology’. Here, we outline how movement ecology can contribute to the broad field of biodiversity research, i.e. the study of processes and patterns of life among and across different scales, from genes to ecosystems, and we propose a conceptual framework linking these hitherto largely separated fields of research. Our framework builds on the concept of movement ecology for individuals, and demonstrates its importance for linking individual organismal movement with biodiversity. First, organismal movements can provide ‘mobile links’ between habitats or ecosystems, thereby connecting resources, genes, and processes among otherwise separate locations. Understanding these mobile links and their impact on biodiversity will be facilitated by movement ecology, because mobile links can be created by different modes of movement (i.e., foraging, dispersal, migration) that relate to different spatiotemporal scales and have differential effects on biodiversity. Second, organismal movements can also mediate coexistence in communities, through ‘equalizing’ and ‘stabilizing’ mechanisms. This novel integrated framework provides a conceptual starting point for a better understanding of biodiversity dynamics in light of individual movement and space-use behavior across spatiotemporal scales. By illustrating this framework with examples, we argue that the integration of movement ecology and biodiversity research will also enhance our ability to conserve diversity at the genetic, species, and ecosystem levels
Effects of air abrasion with alumina or glass beads on surface characteristics of CAD/CAM composite materials and the bond strength of resin cements
ABSTRACT Objective The study aimed to evaluate effects of air abrasion with alumina or glass beads on bond strengths of resin cements to CAD/CAM composite materials. Material and Methods CAD/CAM composite block materials [Cerasmart (CS) and Block HC (BHC)] were pretreated as follows: (a) no treatment (None), (b) application of a ceramic primer (CP), (c) alumina-blasting at 0.2 MPa (AB), (d) AB followed by CP (AB+CP), and (e) glass-beads blasting at 0.4 MPa (GBB) followed by CP (GBB+CP). The composite specimens were bonded to resin composite disks using resin cements [G-CEM Cerasmart (GCCS) and ResiCem (RC)]. The bond strengths after 24 h (TC 0) and after thermal cycling (TC 10,000 at 4–60°C) were measured by shear tests. Three-way ANOVA and the Tukey compromise post hoc tests were used to analyze statistically significant differences between groups (α=0.05). Results For both CAD/CAM composite materials, the None group exhibited a significant decrease in bond strength after TC 10,000 (p0.05). The AB+CP group showed a significantly higher bond strength after TC 10,000 than did the AB group for RC (p<0.05), but not for GCCS. The GBB+CP group showed the highest bond strength for both thermal cyclings (p<0.05). Conclusions Air abrasion with glass beads was more effective in increasing bond durability between the resin cements and CAD/CAM composite materials than was using an alumina powder and a CP
Predicting Landscape-Genetic Consequences of Habitat Loss, Fragmentation and Mobility for Multiple Species of Woodland Birds
Inference concerning the impact of habitat fragmentation on dispersal and gene flow is a key theme in landscape genetics. Recently, the ability of established approaches to identify reliably the differential effects of landscape structure (e.g. land-cover composition, remnant vegetation configuration and extent) on the mobility of organisms has been questioned. More explicit methods of predicting and testing for such effects must move beyond post hoc explanations for single landscapes and species. Here, we document a process for making a priori predictions, using existing spatial and ecological data and expert opinion, of the effects of landscape structure on genetic structure of multiple species across replicated landscape blocks. We compare the results of two common methods for estimating the influence of landscape structure on effective distance: least-cost path analysis and isolation-by-resistance. We present a series of alternative models of genetic connectivity in the study area, represented by different landscape resistance surfaces for calculating effective distance, and identify appropriate null models. The process is applied to ten species of sympatric woodland-dependant birds. For each species, we rank a priori the expectation of fit of genetic response to the models according to the expected response of birds to loss of structural connectivity and landscape-scale tree-cover. These rankings (our hypotheses) are presented for testing with empirical genetic data in a subsequent contribution. We propose that this replicated landscape, multi-species approach offers a robust method for identifying the likely effects of landscape fragmentation on dispersal
On the Estimation Stability of Efficiency and Economies of Scale in Microfinance Institutions
This paper uses a panel data set of microfinance institutions (MFI) across the world to compare several identification strategies of cost efficiency and economies of scale. Concretely, we contrast the non-parametric Data Envelopment Analysis (DEA) with the Stochastic Frontier Analysis (SFA) and a distribution-free identification based on time-invariant heterogeneity estimates. Furthermore, we analyze differences of production functions across regions and investigate the relevance of accounting for unobserved heterogeneity across countries. The results suggest that efficiency rankings of MFIs are robust across identification strategies, but highlight the relevance of accounting for unobserved heterogeneity. We further find substantial economies of scale for a pure financial production process. However, accounting for the multi-dimensional production process of MFIs by including a measure of outreach lowers the estimated extent of economies of scale for the parametric estimations, suggesting that producing outreach creates high transaction costs and requires exploitation of local knowledge
Effect of thermal cycling on denture base and autopolymerizing reline resins
OBJECTIVE: This study evaluated the fracture toughness (FT) of denture base and autopolymerizing reline resins, with and without thermocycling (T). MATERIAL AND METHODS: Specimens of each material (denture base acrylic resin - Lucitone 550 - L; autopolymerizing reline resins - Ufi Gel Hard-UH, Tokuyama Rebase II-TR, New Truliner- NT and Kooliner-K), were produced, notched and divided into two groups (n=10): CG (control group of autopolymerizing reline resins and L): FT tests were performed after polymerization; TG (thermocycled group): FT tests were performed after T (5ºC and 55ºC for 5,000 cycles). RESULTS: Results (MPa.m((1/2))) were analyzed by two-way ANOVA and Tukey's test (p=0.05). L exhibited the highest FT mean values in both groups (CG - 2.33; TG - 2.17). For the CG groups, NT showed the highest FT (1.64) among the autopolymerizing reline resins, and K the lowest (1.04). After T, when the autopolymerizing reline resins were compared, a statistically significant difference in FT was found only between the NT (1.46) and TR (1.00). CONCLUSIONS: Thermocycling increased the FT of K and did not influence the FT of L, UH, TR and NT
Решение оптимизационных задач для систем массового обслуживання с отказами в условиях неопределенности
Построены математические модели расчета показателей качества функционирования вычислительных
сетей, которые можно представить в виде сетей массового обслуживания с отказами. Сформулированы
задачи оптимизации показателей качества функционирования таких сетей при заданных ограничениях
на максимальную пропускную способность каналов связи и на выделяемые для модернизации сети ресурсы. Построены алгоритмы, которые позволяют решать поставленные оптимизационные задачи в
рамках оговоренных ограничений
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