The problem with which this investigation was concerned was the comparison of cedar elm populations in different stands along creeks in Denton County, Texas, and the relationship of certain population parameters to various substrates present at stand sites, Parameters investigated eluded average basal area, basal-area density, transect-segment density, intertree distance, lateral distance, frequency, diameter breast-high, diameter breast-high size-class distribution, and immature-tree density. Variations among populations of Ulmus crassifolia Nutt were noted and analyzed in terms of soil particle size and existing community conditions.

Hylurgopinus rufipes, the native elm bark beetle (NEBB), is the major vector of Dutch elm disease (DED) in Manitoba. Dissections of American elms (Ulmus americana), in the same year as DED symptoms appeared in them, showed that NEBB constructed brood galleries in which a generation completed development, and adult NEBB carrying DED spores would probably leave the newly-symptomatic trees. Rapid removal of freshly diseased trees, completed by mid-August, will prevent spore-bearing NEBB emergence, and is recommended. The relationship between presence of NEBB in stained branch sections and the total number of NEEB per tree could be the basis for methods to prioritize trees for rapid removal. Numbers and densities of overwintering NEBB in elm trees decreased with increasing height, with >70% of the population overwintering above ground doing so in the basal 15 cm. Substantial numbers of NEBB overwinter below the soil surface, and could be unaffected by basal spraying. Mark-recapture studies showed that frequency of spore bearing by overwintering beetles averaged 45% for the wild population and 2% for marked NEBB released from disease-free logs. Most NEBB overwintered close to their emergence site, but some traveled ≥4.8 km before wintering. Studies comparing efficacy of insecticides showed that chlorpyrifos gave 100% control of overwintering NEBB for two years as did bifenthrin: however, permethrin and carbaryl provided transient efficacy. NEBB showed a gradual increase in development rate with increasing constant temperature. Lipid content of overwintering NEBB was higher in late fall than in mid-winter, which might show that depletion of fat reserves could jeopardize survival, but could be a result of conversion to cryoprotectants.

The aim of this thesis was to find out and map the occurrence of elm trees in Novohradske Mountains and in parts of the surrounding foothills. There is a natural occurrence of Wych elm (Ulmus glabra) on the respective territory which was confirmed by my research. I also managed to find six Field elm trees (Ulmus minor) that are not to be found on this territory naturally. A natural occurrence and purposeful growing of Wych elm tree (Ulmus glabra) is also proved in historical records dating as far back as 17th century when the respective territory was part of the Buquoy manor. During my field research I was able to find 40 localities with altogether 783 registered elm trees with the height of over 3 m. Researching the records of Forests of the Czech Republic, State Enterprise I also managed to find 10 more locations where I could register only 12 grown elm trees, since the remaining approximately 580 elm trees up to 5 m of height have been planted in the last decade and their numbers will be changing in the following decades as a result of 4 silvicultural measures. It mostly concerns elm trees that can be found in plastic protection or surrounded by forest fences against animal gnawing. It is interesting that there are several over aged specimen mostly in old alleys on the respective territory and all other elm trees do not exceed the estimated age of 50 years.

No description available.

Nuclear fusion is a research topic that attracts a lot of interest. If properly harnessed, it promises to be an energy source that circumvents problems that current energy sources have. As such, fusion warrants research aimed at understanding and dealing with its varied issues. Fusion is regularly recreated on earth by heating a hydrogen plasma to around a hundred million degrees Celsius. Confining this plasma requires special machines due to the extreme heat. There are multiple types of machines recreating plasma for research purposes, the most common is called tokamak. Tokamaks confine the plasma in a toroidal shape using powerful magnetic fields that prevent particles from escaping. Relevant for this work is the tokamak JET, where the treated experiment has been conducted, and ITER, which is currently under construction and meant to be the next step in fusion research. An important phenomenon are so called Edge Localized Modes (ELMs). ELMs are short bursts of energy expulsions from the plasma that results in a loss of energy and can cause damage to components facing the plasma. While not necessarily present in all operational modes ELMs are present in JET and will be present in ITER. Therefore it is very important to understand ELMs and how they are affected by certain parameters. Especially important is the dependency of ELM size on collisionality, a measurement on how much particles in the plasma interact with each other. Due to how ITER is supposed to operate it will have a very low collisionality, something that previous studies have linked with large ELM energy losses. This work investigates how parameters, plasma density, gas fueling rate, effective mass, strength of the magnetic field and collisionality affect ELMs.  This work calculates the energy losses for ELMs and investigates whether they are related to certain parameters. To calculate the energy loss two methods are deployed. One method relies on measurements of the diamagnetic flux. The other utilizes measurements of temperature and density with thomson scattering, electron cyclotron emission and reflectometry. Both techniques compare the energy in the plasma before and after an ELM to deduce the energy loss. For both methods, ELMs in a time interval are grouped and their data is used to calculate a typical energy loss. The results show that the energy losses from both methods are comparable with previous measurements at similar collisionality. The methods produce comparable results although the results for singular cases are not always in agreement. Ion cyclotron resonance heating is identified as worsening the agreement. A combination of the results being too noisy and there not being enough data means that no clear trends were observed in the investigated parameters. / Fusion är ett intressant forskningsområde. Om det nyttjas på rätt sätt, kan fusion bli en energikälla kringgår problem som nuvarande energikällor har. Därför finns det mycket forskning om fusion med målet att förstå och hantera de problem som idag stoppar fusion från att användas som energikälla. Fusion återskapas på jorden genom att värma väteplasma till cirka hundra miljoner grader Celsius. Att hålla plasmat kräver speciella maskiner på grund av den extrema värmen som lätt smälter alla material. Det finns flera olika maskiner som kan upprätthålla plasma för forskningsändamål, även om de ännu inte kan utvinna energi. Den vanligaste kallas tokamak. Tokamaker håller plasmat i en toroidal form med hjälp av kraftiga magnetfält. För detta arbete är tokamakerna JET och ITER relevanta. Datan som behandlas i detta arbete kommer från JET. ITER är en forskningsreaktor som är under konstruktion och är ämnad att vara nästa steg inom fusionforskning. Ett viktigt phenomen är Edge Localized Modes (ELMs). ELMs är korta energipulser från plasmat som kan orsaka skador på komponenter vända inåt mot plasmat. ELMs är inte nödvändigtvis närvarande men de är närvarande i JET och kommer att vara närvarande i ITER. Därför är det viktigt att förstå dem. Särskilt viktigt är hur ELM-storleken ändras beroende på kollisionalitet, ett mått på hur mycket partiklar i plasmat interagerar med varandra. På grund av hur ITER ska köras kommer kollisionaliteten vara mycket låg, något som tidigare studier har kopplat till stora ELMs. Beroende på vad som utlöser en ELM säger man att de är peeling eller ballooning begränsade. De flesta experimenten idag är ballooning-limited, vilket betyder att ELMs utlöses på grund av en för hög tryckgradient. På grund av den låga kollisionaliteten tros ITER bli peeling-limited, vilket betyder att ELMs utlöses av för höga strömmar i plasmat. I ett försök att härma ITERs operationstillstånd har experimentet som undersöks i detta arbete låg kollisionalitet. De parametrar vars inflytande på ELMs undersöks är plasmats densitet, bränsletillförsel, effektiv massa, styrkan av magnetfältet och kollisionalitet. För att beräkna energiförlusten används två metoder, en använder en mätningar av magnetflödet i plasmat. Den andra metoden använder mätningar av temperaturen och densiteten vid punkter i plasmat. Båda teknikerna jämför energin i plasmat före och efter en ELM för att fastställa energiförlusten. För båda metoderna används alla ELMs under en period för att beräkna en karaktäristisk energiförlust. Energiförlusterna är jämförbara med tidigare mätningar vid liknande kollisionalitet. De använda metoderna ger överlag liknande resultat för de olika undersökta intervallen. Ion Cyclotron Resonance Heating (ICRH) identifieras förvärra överensstämmelsen avsevärt. En kombination av att resultaten har hög osäkerhet och att det finns få datapunkter innebär att tydliga trender inte observerades i de undersökta parametrarna.

The purpose of this study was to examine the suitability of the YSI model 6600 Environmental Monitoring System (multiprobe) for long term deployment at a site in Lewisville Lake, Texas. Specifically, agreement between a laboratory extraction procedure and the multiprobe chlorophyll/fluorescence readings was examined. Preliminary studies involved determining the best method for disrupting algal cells prior to analysis and examining the precision and linearity of the acetone extraction procedure. Cell disruption by mortar and pestle grinding was preferable to bath sonication. Comparison of the chlorophyll/fluorescence readings from the multiprobe and the extraction procedure indicated that they were significantly correlated but temperature dependent.

Ecological research involving habitat studies was conducted on the Elm Fork of the Trinity River in Denton County, Texas, from spring 1985 to spring 1986. Habitat Evaluation Procedures and Habitat Suitability Index Models developed by the United States Fish and Wildlife Service were applied to a 1419 hectares study area to determine the quality of habitat for four species: beaver, Castor canadensis, wood duck, Aix sponsa, pileated woodpecker, Dryocopus pileatus, and white crappie, Poxomis annularis. Population estimates were generated. A wildlife management plan was developed for the study area. Habitat Suitability Index Models were found to be overly conservative, underestimating the quality of habitat in areas of ecological transition.

The spatial and temporal distribution of Methyl Tertiary-Butyl Ether (MTBE) and BTEX (Benzene, Toluene, Ethylbenzene, Xylenes) compounds were assessed in a multipurpose reservoir, Lake Lewisville, Texas between February 1999 and February 2000. Concentrations of MTBE ranged from 0.0 - 16.7 mg/L. Levels of MTBE in the lake were related to watercraft. BTEX concentrations were never detected above 2.0 mg/L during the sampling period. Finished drinking water from Denton and the Upper Trinity Regional Water District (UTRWD) Treatment Plants were also tested for MTBE and BTEX. MTBE and BTEX were not detected in UTRWD water samples. Denton's finished water samples never exceeded 2.2 mg/L for MTBE and BTEX was not detected except for one replicate of 1.1 mg/L toluene.

Master of Science / Department of Horticulture, Forestry, and Recreation Resources / Charles Barden / Cheryl Boyer / Red elm (Ulmus rubra), grey alder (Alnus incana and A. incana spp. tenuifolia) and buffaloberry (Shepherdia canadensis) are considered important plants for many Native American tribes in the United States. Native Americans have used these three species for a variety of medicinal uses and ceremonial purposes. Currently, Kansas tribal leaders would like to plant more of these species on tribal land, but the plants have been difficult to propagate. While red elm is valued as a ceremonial tree, it is susceptible to Dutch Elm Disease caused by the fungus (Ophiostoma ulmi) and is not grown in many ornamental nurseries. This has led to declining tree populations. The objective of these studies were to evaluate methods to propagate red elm, grey alder and buffaloberry in order to find techniques that can lead to an increase in the production of these species commercially and enable tribes and landowners to increase the presence of these native plants on their lands. In the first study, the use of gibberellic acid (GA3) was investigated to determine the optimum concentration needed for maximum seed germination. Studies were conducted with stratified (cold, moist storage) and non-stratified red elm, grey alder, and buffaloberry seeds soaked in one of four treatments: 0, 250, 500 or 1000 ppm of GA3 in 2010, and 0, 500, 1000, 2000 ppm of GA3 in 2011. Results indicate the use of GA3 in high concentrations promoted germination of unstratified seeds of red elm, though low seed viability in grey alder and buffaloberry resulted in poor germination. In a second study, vegetative cuttings were treated with potassium indole-3-butyric acid (K-IBA) and Dip ‘N GrowTM containing indole-3-butyric acid and naphthalene acetic acid (IBA + NAA). Softwood cuttings for the three species were treated with K-IBA and Dip ‘N GrowTM (plant rooting hormones): K-IBA at 5,000 and 10,000 ppm and Dip ‘N GrowTM at 1:10 ratio solutions. Results of this study showed that only grey alder softwood cuttings had callus formation, root growth, and shoot growth while red elm and buffaloberry did not respond to cutting propagation treatments.

A large, multi-basin, reservoir (Garza-Little Elm Reservoir) in north central Texas was studied to determine the relative effects of various parameters on primary productivity. The basins were impounded several years apart,thus allowing the influence of age on water chemistry and biota to be considered. Another principal influence on water quality was secondary sewage effluent that entered one basin from a nearby source.