Pine weevil (Hylobius abietis) preferences among species of conifer seedlings planted on clear-cuts in central Europe

IntroductionAs a result of climate change and bark beetle outbreaks in forests, extensive salvage, and sanitary cutting have been undertaken in Europe, resulting in many clear-cuts with coarse stumps. The populations of pine weevils (Hylobius abietis and Hylobius pinastri) are steadily increasing. A high abundance of pine weevils feeding on seedlings typically results in significant economic losses and prolongs the forest establishment period. However, information on these species spatial distribution and habitat selection patterns, necessary for assessing their harmfulness and subsequently accurately estimating their threat to reforested areas, is lacking. To determine which factors influence spatial selection patterns and seedling type preference, this study investigated which clear-cut factors increase pine weevil abundance and which seedling types (species and age) are the most preferred.MethodsThe experiment was carried out on 20 clear-cuts in the central Czech Republic. We evaluated soil moisture level, average stump distance and diameter, proportion of other conifers, and whether the stumps were mulched. We detected the abundance of pine weevils using pitfall traps. We determined the feeding scar intensity on the first 10 cm of seedling stems on commonly used seedlings for reforestation in central Europe: 1-year-old Scots pine (Pinus sylvestris), European larch (Larix decidua), and 3-year-old Norway spruce (Picea abies), with 1,200 seedlings in total. The individual seedling types alternated in rows. The results were evaluated using generalized linear mixed-effect models (GLMMs). As dependent variables we used total numbers of H. abietis and H. pinastri. The soil moisture level, mulching, proportion of other conifers, average stump diameter, and distance were considered independent variables.ResultsWe found that Norway spruce was the least attractive to pine weevils. We found a higher abundance of H. abietis females in moist clear-cuts, confirming that dry clear-cuts are less suitable for oviposition.ConclusionAccording to our findings, if foresters want to plant coniferous seedlings, it seems that planting older spruce is a better option than planting larch and pine. These findings provide valuable insights for forest management and reforestation strategies, equipping foresters with the knowledge to mitigate the threat of pine weevils and ensure successful forest establishment

Swarming magnetic microrobots for pathogen isolation from milk

Bovine mastitis produced by Staphylococcus aureus (S. aureus) causes major problems in milk production due to the staphylococcal enterotoxins produced by this bacterium. These enterotoxins are stable and cannot be eradicated easily by common hygienic procedures once they are formed in dairy products. Here, magnetic microrobots (MagRobots) are developed based on paramagnetic hybrid microstructures loaded with IgG from rabbit serum that can bind and isolate S. aureus from milk in a concentration of 3.42 10(4) CFU g(-1) (allowable minimum level established by the United States Food and Drug Administration, FDA). Protein A, which is present on the cell wall of S. aureus, selectively binds IgG from rabbit serum and loads the bacteria onto the surface of the MagRobots. The selective isolation of S. aureus is confirmed using a mixed suspension of S. aureus and Escherichia coli (E. coli). Moreover, this fuel-free system based on magnetic robots does not affect the natural milk microbiota or add any toxic compound resulting from fuel catalysis. This system can be used to isolate and transport efficiently S. aureus and discriminate it from nontarget bacteria for subsequent identification. Finally, this system can be scaled up for industrial use in food production.Web of Scienc

Multimodal-driven magnetic microrobots with enhanced bactericidal activity for biofilm eradication and removal from titanium mesh

Modern micro/nanorobots can perform multiple tasks for biomedical and environmental applications. Particularly, magnetic microrobots can be completely controlled by a rotating magnetic field and their motion powered and controlled without the use of toxic fuels, which makes them most promising for biomedical application. Moreover, they are able to form swarms, allowing them to perform specific tasks at a larger scale than a single microrobot. In this work, they developed magnetic microrobots composed of halloysite nanotubes as backbone and iron oxide (Fe3O4) nanoparticles as magnetic material allowing magnetic propulsion and covered these with polyethylenimine to load ampicillin and prevent the microrobots from disassembling. These microrobots exhibit multimodal motion as single robots as well as in swarms. In addition, they can transform from tumbling to spinning motion and vice-versa, and when in swarm mode they can change their motion from vortex to ribbon and back again. Finally, the vortex motion mode is used to penetrate and disrupt the extracellular matrix of Staphylococcus aureus biofilm colonized on titanium mesh used for bone restoration, which improves the effect of the antibiotic’s activity. Such magnetic microrobots for biofilm removal from medical implants could reduce implant rejection and improve patients’ well-being.Web of Science352

Swarming Aqua Sperm Micromotors for Active Bacterial Biofilms Removal in Confined Spaces

Microscale self-propelled robots show great promise in the biomedical field and are the focus of many researchers. These tiny devices, which move and navigate by themselves, are typically based on inorganic microstructures that are not biodegradable and potentially toxic, often using toxic fuels or elaborate external energy sources, which limits their real-world applications. One potential solution to these issues is to go back to nature. Here, the authors use high-speed Aqua Sperm micromotors obtained from North African catfish (Clarias gariepinus, B. 1822) to destroy bacterial biofilm. These Aqua Sperm micromotors use water-induced dynein ATPase catalyzed adenosine triphosphate (ATP) degradation as biocompatible fuel to trigger their fast speed and snake-like undulatory locomotion that facilitate biofilm destruction in less than one minute. This efficient biofilm destruction is due to the ultra-fast velocity as well as the head size of Aqua Sperm micromotors being similar to bacteria, which facilitates their entry to and navigation within the biofilm matrix. In addition, the authors demonstrate the real-world application of Aqua Sperm micromotors by destroying biofilms that had colonized medical and laboratory tubing. The implemented system extends the biomedical application of Aqua Sperm micromotors to include hybrid robots for fertilization or cargo tasks

Modeling spatial interactions on the example of the regional cities

Management and planning of transportation is becoming more important in terms of continuously growing intensity of spatial interactions, which are still mostly realized through transport networks. That's why we can deal with this specific problem of transportation geography using for example spatial interactions modeling. The general aim of the thesis is modeling of spatial interactions and their subsequent comparison with real flows by using calibration in order to predicate the future value of flows taking the planned changes in the transport network in consideration. The main tool used to achieve the goal of the thesis is the gravity model which was applied on the example of regional capitals in the Czech Republic. Based on accomplishments we may say, that centers with lower significance of monitored relations are characterized by further location towards most centers, small number of inhabitants, low intensity of model interactions and lower values of transport intensities with neighboring centers. With the center growth itself, its range of interactions with other centers grows as well. Key Words: spatial interactions modeling, gravity model, model interaction, transport intensity, regional capital

The Impact of External Events on the Market Capitalization of Companies

This diploma thesis analyses the relationship between external events (i.e. events with impact within the Czech Republic which cannot be influenced by local firms) and the value of market capitalization of companies on Prague Stock Exchange. The analysis of the 1994 to 2012 time series showed that even the most important political, economical and other events specific for the Czech Republic only have marginal impacts on values of companies on the Czech stock market. The impacts of corporate events proved to have much stronger such effects. The most advisable investment recommendation thus seems to be to ignore external events when deciding in which stocks to invest

The Effects of Legislation on Insider Trading

Liberal Arts and Humanities - Social Sciences ModuleStudium humanitní vzdělanosti - Společenskovědní modulFaculty of HumanitiesFakulta humanitních studi

Effects of Insider Trading Regulation

This thesis analyses the relationship between insider trading regulation (broadly interpreted) and equity costs of firms on data from the Chinese, South African and Russian capital markets covering the years from 1995 to 2011. Time series analysis showed -- as expected -- that stock markets in each of the countries react in specific ways: E.g. none of the regulatory measures proved effective in decreasing the equity costs in the case of South Africa. Analysis of the Chinses and Russian data showed, however, a possible common feature of the participants on the two markets. It seems that these markets react to mere signals of upcoming regulatory measures rather than on these measures themselves. This interpretation of the results is thus in line with the rational expectations hypothesis

Constitutional Analysis of the Lisbon Treaty

This work applies the constitutional analysis method on the evaluation of the EU constitutional setting's change after the possible approval of the Lisbon Treaty. We will focus on the part of the Treaty that has an impact on the character of the legislation connected with commodity taxation. Specifically, we will analyze the change of the voting rules of the Council and the change of the constitutional cognizance of the Council. After we draw the parallel between the Council and the revenue-maximizing Leviathan, we will be able to advocate for the conclusion of our analysis which is that the base and rates of the commodity taxation will change to the disadvantage of the taxpayer after the approval of the Treaty

The evaluation of provincial cities's interactions

Katedra sociální geografie a region. rozvojeDepartment of Social Geography and Regional Develop.Faculty of SciencePřírodovědecká fakult