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Genetic and environmental components of sperm function in Drosophila melanogasterGuo, Ruijian 22 January 2020 (has links)
Sperm function has been studied in multiple research fields as it is essential to male fertility. In previous studies a variety of sperm traits have been examined as an assessment of sperm function. Among those traits, sperm viability, sperm motility and sperm metabolism are often commonly examined. However, sperm function can be influenced by both environmental and genetic factors. Specifically, nuclear genome has been demonstrated to play a role in sperm function, especially in sperm competitive capacity. There are increasing evidence for effects of mitochondrial genome on sperm function. Mitochondrial genetic variance has been suggested to
affect sperm length and sperm viability in seed beetle and sperm metabolism in rodent. Given the coordinated collaborations between nuclear and mitochondrial genomes in OXPHOS, replication and transcription of mitochondrial genome as well as intergenomic signalling, potential mitonuclear effects on sperm function are expected even though empirical evidence so far remains less. A recent review summarised all the previous work on environmental effects on sperm and found that various factors affects sperm function but largely neglected in ecology and evolution. In the study, we used D. melanogaster as a model to disentangle both genetic and environmental components of sperm function at sperm cell, ejaculate and offspring levels.
We found environmental effects on sperm function in D. melanogaster. Specifically, sperm incubation buffers affect sperm viability in chapter 2 and dietary PUFAs influence sperm volume and metabolism in chapter 4. Nuclear effects were found on sperm viability, sperm quality and male fertility in chapter 3. Mitochondrial genome was found to have an effect on sperm function, i.e. sperm viability and sperm quality differed among mitochondrial haplotypes examined. In addition, sperm function was further modified by the interaction of nuclear and mitochondrial genomes in ageing male. Sperm quality and fertilization success were suggested to be dependent on age-related mitonuclear interaction in chapter 3. Moreover, we examined the mitonuclear coadaptation hypothesis in the function of D. melanogaster sperm. No evidence for mitonuclear coadaptation hypothesis was found for sperm function in D. melanogaster as there were no difference between coadapted and non-coadapted lines in sperm traits examined. Lastly, we found that sperm viability, sperm quality and sperm metabolic rate cannot predict male fertility in D. melanogaster as correlation analysis revealed no relationship between them. Our experiment explored and disentangled the genetic and environmental components of sperm function at multiple levels in D.melanogaster systematically. Our results suggested that both mitochondrial and nuclear genome as well as the interaction between them play a role in sperm function in D. melanogaster. In addition to genetic components, our findings revealed environmental components of Drosophila sperm and suggested that it was phenotypic plastic.
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Ekofyziologie mikroskopické houby Pseudogymnoascus destructans / Ecophysiology of microscopic fungus Pseudogymnoascus destructansHomutová, Karolína January 2014 (has links)
A microscopic fungus Pseudogymnoascus destructans (Ascomycota: Pseudeurotiaceae) causes illness known as white-nose syndrome (WNS) causing death of bats during hibernation. The illness occurs in the North America and in Europe. The fungus is characteristic by asymmetrically curved conidia, by slow growth and growth at low temperatures (below 20 řC). The aim of this study is to clarify properties responsible for unique ecelogy of Pseudogymnoascus destructans by comparison with ecological related or unrelated pathogenic or nonpathogenic fungi. This part includes study of tolerance to physiological stresses and recognition of spectrum of utilizating nutrients (compounds of carbon, nitrogen, phosphorus, sulphur and nutrient supplements). Testing to physiological stresses should help to estimate a potentiality of fungus to spread out of caves. The last aim is to develop a selective isolation medium for P. destructans. Influence of several types of physiological stress (e.g. UVA, UVA with UVB, 25 řC, 30 řC, 37 řC and dryness) was investigated with fluorescent stain propidium iodide (PI) by flow cytometry. The spores of Pseudogymnoascus destructans and three fungi from underground spaces were not viable after 3 weeks at 37 řC. Other stresses did not cause a decreasing of viability or some stresses caused...
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Hydrogen gas in Sweden : Is hydrogen gas a viable energy carrier in Sweden?Björkman, Katarina January 2020 (has links)
Detta arbete innefattar att undersöka hur vätgas kan användas i Sverige, dels för energilagring men även som bränsle för fordon. Den ökande användningen av varierande förnyelsebara energikällor i den svenska energimixen innebär problem med stabilitet i kraftnätet, något som energilagring kan vara en lösning på. Samtidigt finns mål att fasa ut fossila energikällor, exempelvis diesel och bensin, något som transportsektorn är mycket beroende av. Enligt intervjuerna så är ett av de stora hindren för att implementera vätgas i Sverige att det saknas standarder och regelverk. Likaså framkommer det att de intervjuobjektens projekt inom vätgas i nuläget inte är pengamässigt lönsamma. I beräkningarna framkom det att varken det nuvarande fallet eller målfallet leder till lönsamma investeringar. Den sektor som är närmast lönsamhet är transportsektorn som kräver antingen en minskning på 90 % av komponenternas kostnad eller en 10-faldig ökning av priset på fossila bränslen. Slutsatserna dragna i denna studie är att det finns användningsområden för vätgas inom flera områden, bränsle, energilagring och inom industrin, utöver den användningen inom industrin som finns idag. För att ha en hållbar produktion av vätgas bör denna vara med elektrolys som baseras på emissionsfri elektricitet, exempelvis från solceller. De ekonomiska målen, i studien kallat target case, är inte tillräckliga utan ytterligare kostnadsminskningar kommer att behövas. / There is a rising demand for energy and at the same time, fossil fuels need to be phased out due to global warming. This means that the energy needs to come from renewable energy resources, for instance photovoltaics. One issue with such energy sources is that they may have variating production which can induce issues with stability in the electrical grid. This study aims to investigate hydrogen in Sweden as energy storage and vehicle fuel. Methods used are literature review, interviews and calculations. According to the interviews are one of the main issues with implementing hydrogen the lack of standards. Today it is the local fire department who approves of hydrogen system which induces irregularities in the handling. It is also said that none of the projects in the interviews is profitable moneywise, something that also can be seen in the calculations. In order to reach break-even some serious changes with regarding costs of components or the alternative, for instance, fossil fuel and electricity. The application closest to break even is transportation which demands a 90 % decrease in component price or a 10-fold increase in fossil fuel price. In conclusion, there are future applications for hydrogen as energy storage, vehicle fuel and in industry, apart from the current industry applications. The most sustainable way to produce hydrogen is via electrolysis with emission-free electricity. In order for hydrogen to become economically viable, the target case is not enough but even greater cost reductions are needed.
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Field Validation of an Advanced Autonomous Method of Exterior Dam Inspection Using Unmanned Aerial VehiclesBarrett, Benjamin Joseph 01 July 2018 (has links)
The maintenance of infrastructure is critical to the well-being of society. This work focuses on a novel method for inspecting the exterior of dams using unmanned aerial vehicles (UAVs) in an automated fashion. The UAVs are equipped with optical sensors capturing still images. The resulting images are used to generate three-dimensional (3D) models using Structure from Motion (SfM) computer software. The SfM models are then used to inspect the exterior of the dam. As typical dam inspections entail completing a checklist of inspection items with varied degrees of precision (e.g. a concrete spillway may be finely inspected for cracking or joint deterioration while the general stability and water-tightness of a large embankment may be observed from a distance), a targeted inspection is also needed for the UAV method. In conjunction with the work presented in this thesis, a novel algorithm was developed which uses camera view planning across multiple proximity levels to generate a set of camera poses (positions and orientations) which can be collected in an autonomous UAV flight that facilitates generation of SfM models having tiered model quality for targeted inspection of infrastructure features. In this thesis, this novel algorithm and accompanying mobile application (referred to together as the novel advanced autonomous method) were field validated at Tibble Fork Dam, UT. The advanced autonomous method was compared to two other common image acquisition methods—basic autonomous and manual piloted—based on the SfM models produced from the collected image sets. The advanced autonomous method was found to produce models having tiered quality needed for efficient targeted inspection (25% and 50% higher resolution in medium and high priority target areas). The advanced autonomous method was found to produce models having on average 38% higher precise point accuracy (1.3cm) and 53% tighter surface reproducibility (for repeat inspections) (1.9cm) than basic autonomous and manual piloted image acquisition methods. The advanced autonomous method required on average 167% longer flight time and 38% fewer images than the other two methods, resulting in increased field time but decreased processing load. Additionally, viability of the advanced autonomous method for practical dam inspection was assessed through a case study inspection of Tibble Fork Dam using the collected SfM model and corresponding still images. The SfM model and corresponding images were found fully adequate for performing 94% of the inspection tasks and partially adequate for the remaining tasks. In consideration of this and other practical implementation factors such as time and safety, the method appears highly viable as an alternate to or supplement with traditional on-foot visual exterior inspection of dams such as Tibble Fork Dam. Suggestions for future work include adjustments to the optimization framework to improve field efficiency, development of a framework for cooperative inspection using UAV swarms, and development of a more automated workflow that would allow fully-remote dam inspections.
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Ideational Viability of Peace : A case study of ideas related to peace and their consequences for the Cyprus peace processLindqvist Käll, Märta-Stina January 2021 (has links)
The Republic of Cyprus is often thought of as a tourist destination and hot spot for sun thirsty expats. Hidden from plain sight amongst holiday homes and blue waters, it may thus seem counterintuitive that Cyprus is home to a toxic ethno-nationalist political conflict that has mandated one of the longest running United Nations peace interventions to date. Still, life in Cyprus does not resemble a conflict zone. This beckon the conceptual debate of peace as more than the absence of war and raises questions of how peace is perceived by involved actors and subsequently, how it is influenced by subjective ideas. With negotiations stuck in a cycle of stalling and reassuming, the peace process is often described as the Cypriot deadlock. The cause of the deadlock is debated without consensus, but frequently boils down to disagreements over policies and issues of intercommunal mistrust. Looking to nuance these notions, this thesis aims to explain the deadlock ideationally by analysing ideas of peace as expressed by political elites and assess how they influence the peace process. The research presents a typological method for mapping ideational biases corresponding to meta-ideas of International relations theory. The central argument of this thesis is that the Cypriot peace process is deadlocked due to divergent ideational biases of political elites, rendering the rationales and strategies (the ideational underpinnings) behind the peace process ideationally unviable. This desktop study of Cyprus is based of primary data from the official websites of the Republic of Cyprus, the Turkish Republic of Northern Cyprus, and the United Nations, published between January of 2019 and April of 2021.
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Interactions between aquaculture and fisheries, and the viability approach to risk management in harvested ecosystems / Les interactions entre aquaculture et pêche captive, et la viabilité comme approche de gestion du risque dans l'exploitation des écosystèmesRegnier, Esther 20 June 2014 (has links)
Les interactions entre aquaculture et pêche captive, et la viabilité comme approche de gestion du risque dans l'exploitation des écosystèmes. / The world of fisheries is complex, dynamic and contested. At the core of fishery management lie technical challenges but also fundamental socioeconomic issues such as valuation and ownership. So far, as for other natural resources, fisheries resources have been largely over exploited and alarms from the scientific community on rapidly declining stocks and species disappearance have been repeatedly published. In what follows, I first strive to explain the repeated failures to manage fisheries in a sustainable way. In this perspective, I overview existing management instruments and the weaknesses of fisheries governance. Next, I raise the main challenges faced by the aquaculture industry to take over on capture fisheries, as a sustainable source of food security. This leads us to an introduction to the two first chapters of this dissertation, which focuses on the economic and ecological impacts of the expansion of aquaculture, and its implications for the capture fishery sector. Finally, I expose the complexity of managing harvested ecosystems under uncertainty, in practice. Thus, I present the third chapter of this dissertation which puts forward a theoretical management framework grounded in viability theory to deals with risk, ecosystem dynamics and conflicting sustainability objectives. In particular, I examine the different analytical possibilities provided by this framework to handle uncertain dynamics.
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Study of the Mechanisms of Heat Tolerance in Ivy GeraniumsZhang, Mingshu 13 December 2014 (has links)
Ivy geranium (Pelargonium peltatum) is a heat susceptible species with its heat tolerance varying among varieties. Reactive oxygen species (ROS) and in-vivo defense systems are related to plant heat damage and heat tolerance. Application of chelated-iron has also been reported to enhance ivy geranium heat tolerance; however, the correlation of ROS, relative enzyme stability, and iron content to differences in heat tolerance in ivy geraniums is unknown. Here we show that the H2O2 content and ROS scavenging enzyme stability in ivy geranium varies with varieties and active iron is not related to heat tolerance in ivy geranium. H2O2 content in mature leaves in both heat tolerant 'Beach' and sensitive 'Butterfly' increased under heat stress, but 'Butterfly' had a relatively greater increase of this toxic compound. Catalase (CAT) activities in young leaves in both varieties decreased. In young leaves of 'Butterfly', CAT activities decreased to a level significantly lower than that in old leaves while this did not occur in 'Beach'. Superoxide dismutase (SOD) activities in 'Butterfly' young leaves were also decreased. All these phenomenon coincided with the heat tolerance differences of the two varieties. Active iron content only changed with leaf age and did not vary between varieties or treatments. Our results demonstrated that ROS scavenging ability and relative enzyme stability may indicate heat tolerance in ivy geranium and that iron deficiency was not the cause of heat damage. Cell Membrane Themostability (CMT) and Triphenyl Tetrazolium Chloride (TTC) cell viability tests are alternative, laboratory-based screening methods for screening for heat-tolerance. Both CMT and TTC tests can represent the variance in heat tolerance observed in ivy geraniums. The results of both CMT and TTC tests correlated well with plant width and growth indexes although their correlations to plant chlorosis were low. Unlike TTC, CMT strongly correlated with plant width. CMT and TTC tests are complementary laboratory-based methods that can be applied to cultivar screening for heat tolerance in ivy geraniums.
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Studium cytotoxicity látek in vitro / Study on cytotoxicity of compounds in vitro.Vašková, Lucie January 2021 (has links)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology and Toxicology Studentka: Lucie Vašková Školitel: RNDr. Jana Maixnerová, Ph.D. Název diplomové práce: Study on cytotoxicity of compounds in vitro The subject of this diploma thesis was to assess the effect of newly synthesized antimycobacterial substances on the viability of human hepatocellular carcinoma (HepG2) cells. The tested substances were esters (HE-nMe, HE-4PHOPH, HE-KARVA, HE-2NAFT, HE-METRO, HE-CH2PY, HE-8CHIN) and thioesters (HES-4H, HES- nETH) of antituberculotic isoniazid. Experiments performed with these substances have shown, that like isoniazid, the substances inhibit InhA enzyme in mycobacteria and therefore interfere with cell wall biosynthesis. Isoniazid is a drug standardly used in the first line of TB treatment. Together with other first-line antituberculotics, some hepatotoxic potential has been reported during treatment. To assess the possible cytotoxic effect of the tested isoniazid derivatives, the standard human hepatocyte cell line HepG2 was chosen as the cell model. Cell viability was assessed by a colorimetric method that measures the metabolic activity of cells based on the reduction of the tetrazolium compound MTS. Obtained values were quantitatively compared using the toxicological...
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Evaluation Of The Biodegradability And Toxicity Of Pca And MpcaRueda, Juan 01 January 2013 (has links)
The main types of hypergolic propellants used at Kennedy Space Center (KSC) are hydrazine (HZ) and monomethylhydrazine (MMH). HZ and MMH are classified as hazardous materials and they are also known to be potentially carcinogenic to humans; therefore, handling these substances and their waste is strictly regulated. The wastes streams from HZ and MMH have been estimated to be the main hazardous wastes streams at KSC. Currently at KSC these wastes are first neutralized using citric acid and then they are transported on public roads for incineration as hazardous materials. A new method using alpha ketoglutaric acid (AKGA) was proposed to treat HZ and MMH wastes. From the reaction of AKGA with HZ and MMH two stable products are formed, 1,4,5,6-tetrahydro-6-oxo-3-pyridazinecarboxylic acid (PCA) and lmethyl-1,4,5,6-tetrahydro-6-oxo-3-pyridazinecarboxylic acid (mPCA), respectively. The cost of purchasing AKGA is greater than the cost of purchasing citric acid; thus, AKGA can only become a cost effective alternative for the treatment of HZ and MMH wastes if the products of the reactions (PCA and mPCA) can be safely disposed of into the sewage system without affecting the treatment efficiency and effluent quality of the wastewater treatment plant (WWTP). In this research mPCA and PCA were analyzed for acute toxicity using fish and crustaceans as well as their effect on the wastewater treatment efficiency and viability using AS microbes, and their biodegradability by AS organisms. Acute toxicity on fish and crustaceans was investigated according to the methods for acute toxicity by USEPA (USEPA Method EPA- 821-R-02-012) using Ceriodaphnia dubia (96 hours) and Pimephales promelas (96 hours) as the test organisms. The effect of mPCA and PCA in the treatment efficiency and viability were iii estimated from respiration inhibition tests (USEPA Method OCSPP 850.3300) and heterotrophic plate counts (HPCs). Lastly, the biodegradability of mPCA and PCA was assessed using the Closed Bottle Test (USEPA Method OPPTS 835.3110). For mPCA, the 96 hours LC50 for C. dubia was estimated at 0.77 ± 0.06 g/L (with a 95% confidence level) and the NOEC was estimated at 0.5 g/L. For P. promelas, the LC50 was above 1.5 g/L but it was noticed that mPCA had an effect on their behavior. Abnormal behavior observed included loss of equilibrium and curved spine. The NOEC on the fish was estimated at 0.75 g/L. PCA did not exhibit a significant mortality on fish or crustaceans. The LC50 of PCA in P. promelas and C. dubia was > 1.5 g/L and the NOEC was 1.5 g/L for both organisms. An Inhibitory effect on the heterotrophic respiration of activated sludge organisms was not observed after exposing them for 180-min to PCA and mPCA at concentrations of up to 1.5 g/L compared to the blank controls. Overall the impact of PCA and mPCA on total respiration rates was small, and only observed at 1,500 mg/L if at all. The difference was apparently caused by inhibition of nitrification rather than heterotrophic inhibition. However due to the variability observed in the measurements of the replicates, it is not possible to firmly conclude that PCA or mPCA at 1,500 mg/L was inhibitory to nitrification. Based on the results from the HPCs, mPCA and PCA did not affect the viability of heterotrophic organisms at 750 mg/L. In the BOD-like closed bottle test using a diluted activated sludge mixed liquor sample, the AS microorganisms were capable of biodegrading up to 67% of a 2 mg/L concentration of PCA (with respect to its theoretical oxygen demand, or ThOD) in 28 days. No biodegradation was observed in the samples containing 2 and 5 mg/L of mPCA after 28 days of incubation using a diluted activated sludge mixed liquor sample as inoculum. iv The results of this study show that mPCA is more toxic than PCA to Ceriodaphnia dubia and Pimephales promelas. However neither mPCA nor PCA had an effect on the heterotrophic respiration of an AS mixed liquor sample at 1.5 g/L and there was probably no significant inhibition of the nitrification respiration. Samples of PCA and mPCA at 2 and 5 mg/L could not be completely degraded (with respect to their total theoretical oxygen demand) by dilute AS biomass during a 28 day incubation period. mPCA did not show significant degradation in the two different biodegradation tests performed.
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Hatching Asynchrony Occurs As A Byproduct Of Maintaining Egg ViabilityAldredge, Robert 01 January 2008 (has links)
For many organisms, embryonic development begins directly after an egg (ovum) has been fertilized by sperm; however, some organisms delay the onset of embryonic development until conditions are favorable for raising young. This delayed onset of development could occur by delaying implantation of fertilized ovum on the uterine wall, as seen in many mammals. Birds delay embryonic development by laying a set of fertilized ova over a period of consecutive days. These fertilized ova are protected from the ambient environment by an exterior shell, and it is in this shell outside of the female s body that embryonic development occurs, but only when females initiate incubation. The number of fertilized ova (eggs) that can be laid by a single female in a single clutch varies among and within bird species, and understanding this variation remains a vital, unanswered question in ornithology. A latitudinal gradient in clutch size is widely recognized, but the reason for this pattern is unclear. Some birds lay relatively large clutches over many days, thus we should expect that eggs could withstand fairly long exposure to ambient temperature and remain viable. However, recent evidence suggests that egg viability declines with increased exposure to ambient temperatures. The egg viability hypothesis predicts that eggs will fail to hatch if exposed to warm ambient temperatures for prolonged periods. I conducted a natural experiment to determine whether egg viability can explain site-specific variation in hatching failure. Hatching failure is higher in a suburban population of Florida Scrub-Jays than it is in a wildland population, possibly because suburban scrub-jays lay larger clutches. Scrub-jays, like many bird species, lay one egg per day and begin incubation with the last-laid egg, thus first-laid eggs in the larger suburban clutches should be exposed to the warm ambient temperatures of sub-tropical Florida longer than first-laid eggs in the smaller clutches typical of the wildland population. As predicted, I found hatching failure is higher in first-laid eggs in the suburbs, and these eggs experience increased exposure to warm ambient temperatures. At both sites, females appear to begin incubation earlier in the laying period as ambient temperatures increase seasonally, possibly to minimize exposure to warm ambient temperatures and minimize hatching failure in first-laid eggs. However, early onset of incubation causes eggs to hatch asynchronously ( > 24 hours between the first and last-hatched egg), and hatching asynchrony increases within-brood size-asymmetries, which leads to an increased frequency of brood reduction (the nonrandom loss of last-hatched young because of starvation). Thus, a tradeoff may exist between beginning incubation earlier in the laying period to minimize hatching failure in first-laid eggs and delaying the onset of incubation to minimize hatching asynchrony and brood reduction. This tradeoff can have profound effects on avian clutch sizes, and may potentially explain the widely known negative relationship between latitude and clutch size.
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