2957 research outputs found
Sort by
Nephrocalcinosis in farmed salmonids: diagnostic challenges associated with low performance and sporadic mortality
Get PDFDisease conditions that involve multiple predisposing or contributing factors, or manifest as low performance and/or low-level mortality, can pose a diagnostic challenge that requires an interdisciplinary approach. Reaching a diagnosis may also be limited by a lack of available clinical profile parameter reference ranges to discriminate healthy fish from those affected by specific disease conditions. Here, we describe our experience investigating poorly performing rainbow trout (Oncorhynchus mykiss) in an intensive recirculation aquaculture, where reaching a final diagnosis of nephrocalcinosis was not as straightforward as one would wish. To list the issues making the diagnosis difficult, it was necessary to consider the creeping onset of the problem. Further diagnostic steps needed to ensure success included obtaining comparative data for fish blood profiles and water quality from both test and control aquacultural systems, excluding infections with salmonid pathogenic agents and evaluating necropsy findings. Major events in the pathophysiology of nephrocalcinosis could be reconstructed as follows: aquatic environment hyperoxia and hypercapnia RIGHTWARDS ARROW blood hypercapnia RIGHTWARDS ARROW blood acid-base perturbation (respiratory acidosis) RIGHTWARDS ARROW metabolic compensation (blood bicarbonate elevation and kidney phosphate excretion) RIGHTWARDS ARROW a rise in blood pH RIGHTWARDS ARROW calcium phosphate precipitation and deposition in tissues. This case highlights the need to consider the interplay between water quality and fish health when diagnosing fish diseases and reaching causal diagnoses.O
Effect of Norway Spruce Forest Dieback on Soil Water Balance: The Examples from Upland Areas of the Czech Republic
No full textThis study focuses on the description of soil water balance under three different spruce monoculture conditions, nemaly living forest, disturbed forest with dead trees and after forest clear-cutting. Analysis was based on sampling instantaneous moisture in surface soil layers in a non-rainfall period and soil water content measurements from the last-half of 2021. We investigated both column daily soil moisture and its vertical distribution in invidual soil layers. Highest soil moisture was observed in the disturbed forest, the other sites generally having comparatively lower soil moisture, probably due to higher evapotranspiration and different soil properties.Published Versio
Evaluation of yield and alpha acid content in selected hop varieties
Get PDFThe stability of the agricultural and technological properties of hop varieties over the course of time and under changing climate is essential for both growers and brewers. This study is a typical case of monitoring 12 hop varieties selected from a collection of hop genetic resources, that were evaluated in the years 2009 to 2021. The assessed parameters were the hop yield and content of alpha acids with a focus on the variability/stability of this characteristics. Only the Pilgrim and Target hop varieties from England showed exceptional hop yield above 3 kg/plant. On the other hand, the lowest hop yield was obtained from the Saaz and Bramling Cross hop varieties, i.e. below 1.5 kg/plant. The lowest variability of hop yield - below 30% - was found in the Savinjski Golding, Bramling Cross and Saaz hop varieties. In contrast, the Bobek, Aurora, Pioneer and Phoenix hop varieties demonstrated the highest variability of hop yield, i.e. above 50%. Further, also Target and Phoenix have the highest content of alpha acids, namely 9.68% w/w and 9.56% w/w, respectively. The lowest content of alpha acids was determined in Saaz, which was the only hop variety with an alpha acid content below 3.0% w/w. The Premiant, Target and Aurora hop varieties exhibited a variability of alpha acid content below 20%. On the contrary, the Bobek and Pilgrim hop varieties had the highest variability of alpha acid content, namely above 30%.O
Reproductive toxicity of combined effects of endocrine disruptors on human reproduction
Get PDFConfluence of environmental, genetic, and lifestyle variables is responsible for deterioration of human fecundity. Endocrine disruptors or endocrine disrupting chemicals (EDCs) may be found in a variety of foods, water, air, beverages, and tobacco smoke. It has been demonstrated in experimental investigations that a wide range of endocrine disrupting chemicals have negative effects on human reproductive function. However, evidence on the reproductive consequences of human exposure to endocrine disrupting chemicals is sparse and/or conflicting in the scientific literature. The combined toxicological assessment is a practical method for assessing the hazards of cocktails of chemicals, co-existing in the environment. The current review provides a comprehensive overview of studies emphasizing the combined toxicity of endocrine disrupting chemicals on human reproduction. Endocrine disrupting chemicals interact with each other to disrupt the different endocrine axes, resulting in severe gonadal dysfunctions. Transgenerational epigenetic effects have also been induced in germ cells, mostly through DNA methylation and epimutations. Similarly, after acute or chronic exposure to endocrine disrupting chemicals combinations, increased oxidative stress (OS), elevated antioxidant enzymatic activity, disrupted reproductive cycle, and reduced steroidogenesis are often reported consequences. The article also discusses the concentration addition (CA) and independent action (IA) prediction models, which reveal the importance of various synergistic actions of endocrine disrupting chemicals mixtures. More crucially, this evidence-based study addresses the research limitations and information gaps, as well as particularly presents the future research views on combined endocrine disrupting chemicals toxicity on human reproduction.O
How to support carbon sequestration and recreational potential at the same time
No full textIn recent years, planting trees to protect the climate has become very popular both in the world and here in the Czech Republic. The Paris Agreement in December 2015 and the resulting Nationally Determined Contributions significantly supported the need for the creation and improvement of carbon accounting methods for investments into the forest sector. Appropriately chosen and well-executed tree planting offers a natural, ecological, relatively cheap, and above all simple way to reduce the amount of carbon dioxide (CO2) in the atmosphere as well a number of other environmental benefits. One of these benefits is the positive effects on human well-being and landscape aesthetics both of which is commonly utilized to support recreational potential. However, understanding the financial value of environmental benefits (ecosystem functions) of natural ecosystems and woody vegetation has been an ongoing challenge that still limits the full utilization of close-to-nature landscape management up to this day. Here we show how carbon sequestration potential of individual trees can be evaluated which can in return serve as a motivation tool for conscious tree planting in the rural landscape during all steps of decision making process.Published Versio
Meteorological activities of J. G: Mendel as part of a tour of the Augustinian Abbey
No full textGregor Johann Mendel is known worldwide for establishing the genetic laws. What is less well known is that during his life he devoted far more time to meteorology. He started as an assistant to Dr. Olexíka, who performed meteorological measurements on the premises of the Hospital at St. Anna in Brno. G.J. Mendel independently carried out his measurements in the grounds of the Augustinian Abbey in Staré Brno from July 1878 to July 1883 as a meteorological observer of the Austrian Meteorological Services. He studied at the University of Vienna and used his knowledge of physics to process meteorological data, which was unusually extensive and graphically expressed for that time. His physically very expertly described tornado that occurred in Brno on October 10, 1870 is very well known. He supported the development of weather forecasts and and forecasts with specifically focused on agriculture. Part of the exposition in the Mendel Museum of the Masaryk University in Brno is dedicated to his meteorological activities. Visitors to the Abbey can familiarize themselves with the meteorological instruments located in the meteorological booth on the terrace. In the courtyard, there is a replica of the tin meteorological booth from the period of Mendel's measurements in its original place.Published Versio
Assessment of landfill protection systems in Japan - a case study
Get PDFLandfilling of untreated waste is still seen as an acceptable practice in many developed countries. Sanitary landfills are facilities for the disposal of untreated mixed municipal solid waste as a major waste stream. The Waste Management and Public Cleansing Act of 1970 is the main waste legislation in Japan. Waste management methods differ in Japan from the European Union and other countries. As waste incineration is prevalent in Japan, the final waste disposal rate in landfills is extremely low, occupying less than 5% of the waste generated. In Japan, there are obligatory barrier systems, treatment facilities for leachate and concrete structures for major facilities (waste storage structures, barriers, and leachate treatment facilities), landfill operations (dumping and soil covering) and management facilities (weighing and monitoring equipment) which are identified in the Guideline Manual of Landfill Site. This work examines the landfill protection systems in Japan based on two case studies from selected research facilitiesO
Interaction of the Nanoparticles and Plants in Selective Growth Stages-Usual Effects and Resulting Impact on Usage Perspectives
Get PDFNanotechnologies have received tremendous attention since their discovery. The current studies show a high application potential of nanoparticles for plant treatments, where the general properties of nanoparticles such as their lower concentrations for an appropriate effects, the gradual release of nanoparticle-based nutrients or their antimicrobial effect are especially useful. The presented review, after the general introduction, analyzes the mechanisms that are described so far in the uptake and movement of nanoparticles in plants. The following part evaluates the available literature on the application of nanoparticles in the selective growth stage, namely, it compares the observed effect that they have when they are applied to seeds (nanopriming), to seedlings or adult plants. Based on the research that has been carried out, it is evident that the most common beneficial effects of nanopriming are the improved parameters for seed germination, the reduced contamination by plant pathogens and the higher stress tolerance that they generate. In the case of plant treatments, the most common applications are for the purpose of generating protection against plant pathogens, but better growth and better tolerance to stresses are also frequently observed. Hypotheses explaining these observed effects were also mapped, where, e.g., the influence that they have on photosynthesis parameters is described as a frequent growth-improving factor. From the consortium of the used nanoparticles, those that were most frequently applied included the principal components that were derived from zinc, iron, copper and silver. This observation implies that the beneficial effect that nanoparticles have is not necessarily based on the nutritional supply that comes from the used metal ions, as they can induce these beneficial physiological changes in the treated cells by other means. Finally, a critical evaluation of the strengths and weaknesses of the wider use of nanoparticles in practice is presented.O
Winter Food Availability for Wild Herbivores Depending on the Type of Forest Regeneration
Get PDFThis study compares the amount of available biomass for wild herbivores (red deer (Cervus elaphus L.), roe deer (Capreolus capreolus L.), and hare (Lepus europaeus Pallas)) depending on three different types of forest silvicultural systems-presented using the example of beech and spruce stands in wintertime. During the winter period, spruce provided ten times more biomass for herbivores than beech. However, beech provided more metabolizable energy, 7.38 MJ/kg on average, whereas spruce only provided 6.57 MJ/kg. From the point of view of "risk of damage by herbivores", artificial regeneration suffered the worst damage after using the Clear Cutting method of forest regeneration, as there was the least amount of biomass available, and thus, herbivores caused the greatest damage. On average, 12% of shoots were damaged in clearings. Most at risk was young forest vegetation up to 1 m tall. In summer, the area was overgrown with available plants, but in winter, the herbivores focused mainly on eating woody shoots. Damage to the natural regeneration when using the Shelterwood Cutting and Strip Cutting regeneration methods ranged up to 3%. At the same time, a high amount of available biomass was measured there, most likely due to its frequent natural regeneration. Thus, both types of trees regenerated in this way were not as susceptible to damage by herbivores as when regenerated using the Clear Cutting method.O
Stability of intemetallic phases in the heat affected zone depending on shielding gases
No full textThis contribution deals with the influence of shielding gases on the parameters of MIG and MAG welds. For the experiment purposes, steels S 235 JRG1 and C45 were chosen. In the research part, welding parameters and welding conditions were proposed; based on them, a series of experiments were performed. Weld beads were subjected to metallographic analysis (samples prepared according to ČSN ISO 4967), from which the heat-affected zone and metal structure were determined. The melting bath area was not analyzed. Furthermore, in the heat-affected zone there were hardness and microhardness measured. The macrohardness of the samples was measured using the Rockwell HRB method according to ČSN EN ISO 6508 standard. The microhardness measurement was performed using Hannemann microhardness tester according to ČSN EN ISO 6507-1 standard.Published Versio