Better understanding of the role of vegetation in the transport of fluid and pollutants requires improved knowledge of the detailed flow structure within the vegetation. Instead of spatial averaging, this study uses discrete measurements at multiple locations within the canopy to develop velocity and turbulence intensity profiles and observe the changes in the flow characteristics as water travels through a vegetation array simulated by rigid dowels. Velocity data were collected with a one dimensional laser Doppler velocimeter (LDV) under single layer emergent and submerged flow conditions, and through two layers of vegetation. The effects of dowel arrangement, density, and roughness are also examined under the single layer experiments. The results show that the velocity within the vegetation array is constant with depth and the velocity profile is logarithmic above it. The region immediately behind a dowel, where the vorticity and turbulence intensity are highest, is characterized by a velocity spike near the bed and an inflection point near the top of the dowel arrays. With two dowel layers, the velocity profile in the region behind a tall dowel exhibits multiple inflection points and the highest turbulence intensities are found there. / Master of Science

Yes / This review paper addresses the structure of the mean flow and key turbulence quantities in free-surface flows with emergent vegetation. Emergent vegetation in open channel flow affects turbulence, flow patterns, flow resistance, sediment transport, and morphological changes. The last 15 years have witnessed significant advances in field, laboratory, and numerical investigations of turbulent flows within reaches of different types of emergent vegetation, such as rigid stems, flexible stems, with foliage or without foliage, and combinations of these. The influence of stem diameter, volume fraction, frontal area of stems, staggered and non-staggered arrangements of stems, and arrangement of stems in patches on mean flow and turbulence has been quantified in different research contexts using different instrumentation and numerical strategies. In this paper, a summary of key findings on emergent vegetation flows is offered, with particular emphasis on: (1) vertical structure of flow field, (2) velocity distribution, 2nd order moments, and distribution of turbulent kinetic energy (TKE) in horizontal plane, (3) horizontal structures which includes wake and shear flows and, (4) drag effect of emergent vegetation on the flow. It can be concluded that the drag coefficient of an emergent vegetation patch is proportional to the solid volume fraction and average drag of an individual vegetation stem is a linear function of the stem Reynolds number. The distribution of TKE in a horizontal plane demonstrates that the production of TKE is mostly associated with vortex shedding from individual stems. Production and dissipation of TKE are not in equilibrium, resulting in strong fluxes of TKE directed outward the near wake of each stem. In addition to Kelvin–Helmholtz and von Kármán vortices, the ejections and sweeps have profound influence on sediment dynamics in the emergent vegetated flows.

<p>U&nbsp; radu&nbsp; je&nbsp; analizirana&nbsp; flora&nbsp; i&nbsp; vegetacija&nbsp; Deliblatske pe&scaron;čare. Cilj istraživanja bio je utvrđivanje&nbsp; recentnog stanja&nbsp; i&nbsp; osnovnih&nbsp; karakteristika&nbsp; flore&nbsp; Deliblatske pe&scaron;čare,&nbsp; ali&nbsp; i&nbsp; analiza&nbsp; dinamike&nbsp; flore&nbsp; Deliblatske pe&scaron;čare u poslednjih 220 godina. Jedan od ciljeva je bila analiza sukcesivnih promena u flori i vegetaciji Deliblatske&nbsp; pe&scaron;čare&nbsp; i&nbsp; predikcija&nbsp; njihovog&nbsp; pravca&nbsp; i kvaliteta,&nbsp; kao&nbsp; i&nbsp; utvrđivanje&nbsp; diverziteta&nbsp; i sintaksonomske &scaron;eme vegetacije Deliblatske pe&scaron;čare uz klasifikaciju problematičnih vegetacijskih grupa u &scaron;irem aspektu- na nivou čitave Srbije, ali i Pontskog i Panonskog regiona. Terenska istraživanja su vr&scaron;ena u periodu&nbsp; 2012-2018&nbsp; godine.&nbsp; Floristički&nbsp; podaci&nbsp; su uzimani&nbsp; na&nbsp; istim&nbsp; lokalitetima&nbsp; kao&nbsp; i&nbsp; fitocenolo&scaron;ki snimci.&nbsp; Ukupno&nbsp; je&nbsp; uzeto&nbsp; 282&nbsp; fitocenolo&scaron;ka&nbsp; snimka metodom po Braun-Blankeu. Za florističku analizu je<br />obrađena&nbsp; 301&nbsp; referenca,&nbsp; a&nbsp; na&nbsp; terenu&nbsp; su&nbsp; prikupljeni podaci&nbsp; za&nbsp; 440&nbsp; vrsta,&nbsp; od&nbsp; kojih&nbsp; je&nbsp; 6&nbsp; po&nbsp; prvi&nbsp; put registrovano na ovom području. U florističku analizu je uključeno&nbsp; ukupno prikupljenih&nbsp; 9.887&nbsp; podataka. U radu je dat floristički pregled u vidu spiska taksona koji&nbsp; su&nbsp; zabeleženi&nbsp; na&nbsp; Deliblatskoj&nbsp; pe&scaron;čari&nbsp; (ima&nbsp; ih 1072),&nbsp; sa&nbsp; lokalitetima&nbsp; na&nbsp; kojima&nbsp; su&nbsp; do&nbsp; sada pronađeni,&nbsp; obeleženi&nbsp; su&nbsp; prvi&nbsp; nalazi&nbsp; za&nbsp; vrste&nbsp; i<br />podvrste, a obeležene su i vrste koje su potvrđene na terenskim&nbsp; istraživanjima&nbsp; u&nbsp; okviru&nbsp; ove&nbsp; disertacije. Floristička&nbsp; analiza&nbsp; je&nbsp; realizovana&nbsp; klasičnim numeričkim&nbsp; metodama,&nbsp; u&nbsp; cilju&nbsp; prezentacije najzastupljenijih&nbsp; familija,&nbsp; rodova,&nbsp; životnih&nbsp; formi&nbsp; i<br />horotipova.&nbsp; Predstavljene&nbsp; su&nbsp; endemične,&nbsp; reliktne&nbsp; i ugrožene&nbsp; i&nbsp; ivnazivne&nbsp; vrste&nbsp; Pe&scaron;čare.&nbsp; Na&nbsp; Deliblatskoj pe&scaron;čari je zabeleženo 16 endemskih, 22 reliktnih, 49 strogo&nbsp; za&scaron;tićenih,&nbsp; 8&nbsp; iz&nbsp; Crvenje&nbsp; knjige&nbsp; flore&nbsp; Srbije&nbsp; i 54&nbsp; invazivna&nbsp; taksona.&nbsp; Dinamika&nbsp; florističkih istraživanja&nbsp; je&nbsp; predstavljena&nbsp; analizom&nbsp;&nbsp; literaturnih podataka i dinamike istraživanja ovog područja, a u skladu&nbsp; sa&nbsp; značajnim&nbsp; dru&scaron;tvenim&nbsp; promenama područja,&nbsp; od&nbsp; kojih&nbsp; se&nbsp; kao&nbsp; najznačajniji&nbsp; momenat izdvaja&nbsp; početak&nbsp; po&scaron;umljavanja&nbsp; Pe&scaron;čare.&nbsp; U&nbsp; pregledu vegetacije&nbsp; Deliblatske&nbsp; pe&scaron;čare&nbsp; su&nbsp; predstavljeni najznačajniji vegetacijski tipovi ovog područja, date su&nbsp; fitocenolo&scaron;ke&nbsp; tabele&nbsp; snimaka&nbsp; koji&nbsp; su&nbsp; za&nbsp; ove zajednice&nbsp; uzeti&nbsp; u&nbsp; toku&nbsp; terenskog&nbsp; istraživanja, fotografije zajednica i mape sa tačkama na kojima su uzimani&nbsp; snimci.&nbsp; U&nbsp; okviru&nbsp; pregleda&nbsp; vegetacije Deliblatske pe&scaron;čare, pored već poznatih vegetacijskih jedinica,&nbsp; po&nbsp; prvi&nbsp; put&nbsp; su&nbsp; predstavljene&nbsp; tri&nbsp; asocijacije autohtone&nbsp; vegetacije&nbsp; i&nbsp; dve&nbsp; sastojine&nbsp; antropogenih zajednica.&nbsp; U&nbsp; cilju&nbsp; razre&scaron;avanja&nbsp; problematike klasifikacije&nbsp; pe&scaron;čarske&nbsp; vegetacije,&nbsp; prikupljeni&nbsp; su&nbsp; i<br />analizirani fitocenolo&scaron;ki podaci za čitavu Srbiju, ali i ceo&nbsp; Panonski&nbsp; i&nbsp; Pontski&nbsp; basen.&nbsp; Na&nbsp; ovaj&nbsp; način&nbsp; je detaljno&nbsp; razja&scaron;njena&nbsp; klasifikacija&nbsp; psamofitskih zajednica&nbsp; Deliblatske&nbsp; pe&scaron;čare&nbsp; do&nbsp; nivoa subasocijacija. Dinamika&nbsp; vegetacije&nbsp; Deliblatske&nbsp; pe&scaron;čare&nbsp; je analizirana&nbsp; praćenjem&nbsp; sukcesivnih&nbsp; stadijuma obrastanja&nbsp; peska&nbsp; i&nbsp; zatvaranjem&nbsp; sklopa&nbsp; sastojina. Monitoring je podrazumevao i pedolo&scaron;ke analize na<br />na&nbsp; lokalitetima&nbsp; različitih&nbsp; vegetacijskih&nbsp; tipova.&nbsp; U okviru&nbsp; praćenja&nbsp; dinamike&nbsp; vegetacije,&nbsp; realizovana&nbsp; su istraživanja&nbsp; na&nbsp; područjima&nbsp; na&nbsp; kojima&nbsp; se&nbsp; vr&scaron;i revitalizacija stepskih sastojina. Rezultati ukazuju da je&nbsp; su&nbsp; revitalizacijom&nbsp; postignuti&nbsp; dobri&nbsp; rezultati&nbsp; koje treba&nbsp; dalje&nbsp; usmeravati&nbsp; i&nbsp; korigovati&nbsp; u&nbsp; pravcu postizanja&nbsp; optimalnih&nbsp; uslova&nbsp; za&nbsp; opstanak&nbsp; i&nbsp; razvoj stepske, ali i drugih tipova vegetacije.<br />Rezultati&nbsp; ove&nbsp; doktorske&nbsp; disertacije&nbsp; daju&nbsp; dobru osnovu za dalja floristička i vegetacijska istraživanja Deliblatske&nbsp; pe&scaron;čare,&nbsp; ali&nbsp; i&nbsp; drugih,&nbsp; sličnih,&nbsp; prirodnih<br />područja&nbsp; i&nbsp; značajan&nbsp; doprinos&nbsp; proučavanju&nbsp; flore&nbsp; i vegetacije Srbije.</p> / <p>In this research was analyzed flora and vegetation of the&nbsp; Deliblato&nbsp; Sands.&nbsp; The&nbsp; aim&nbsp; of&nbsp; the&nbsp; study&nbsp; was&nbsp; to determine the recent state and basic characteristics of the flora of Deliblato Sands, as well as to analyze the dynamics&nbsp; of&nbsp; flora&nbsp; in&nbsp; the&nbsp; last&nbsp; 220&nbsp; years.&nbsp; One&nbsp; of&nbsp; the aims&nbsp; was&nbsp; to&nbsp; analyze&nbsp; the&nbsp; successive&nbsp; changes&nbsp; in&nbsp; the flora&nbsp; and&nbsp; vegetation&nbsp; of&nbsp; Deliblato&nbsp; Sands&nbsp; and&nbsp; the prediction of their direction and&nbsp; quality. Also, one of the&nbsp; goals&nbsp; was&nbsp; to&nbsp; determine&nbsp; the&nbsp; diversity&nbsp; and syntaxonomical&nbsp; scheme&nbsp; of&nbsp; vegetation&nbsp; through classification&nbsp; of problematic vegetation groups in the wider&nbsp; aspect&nbsp; -&nbsp; at&nbsp; the&nbsp; level&nbsp; of&nbsp; the&nbsp; whole&nbsp; Serbia,&nbsp; but also of Pontic and Pannonian region. Field&nbsp; research were&nbsp; carried&nbsp; out&nbsp; in&nbsp; the&nbsp; period&nbsp; 2012-2018.&nbsp; Floristic data were taken at the same sites as phytocenological plots.&nbsp; In&nbsp; total,&nbsp; 282&nbsp; phytosociological&nbsp; relev&eacute;s&nbsp; were taken&nbsp; using&nbsp; the&nbsp; Braun-Blanquet&nbsp; method.&nbsp; 301 different&nbsp; references&nbsp; were&nbsp; processed&nbsp; for&nbsp; floristic analysis&nbsp; and&nbsp; data&nbsp; for&nbsp; 440&nbsp;&nbsp; species&nbsp; were&nbsp; collected&nbsp; in the field&nbsp; (6 of them&nbsp; were registered for the first time in&nbsp; this&nbsp; area).&nbsp; A&nbsp; total&nbsp; of&nbsp; 9,887&nbsp; data&nbsp; collected&nbsp; were included in the floristic analysis. The&nbsp; research&nbsp; gives a&nbsp; floristic&nbsp; overview&nbsp; in&nbsp; the&nbsp; form&nbsp; of&nbsp; a&nbsp; list&nbsp; of&nbsp; taxa recorded&nbsp; in&nbsp; Deliblato&nbsp; Sandst&nbsp; (there&nbsp; are&nbsp; 1072&nbsp; taxa), with the localities where they have been&nbsp; found so far, and&nbsp; the first findings for species and subspecies are marked, as well as the&nbsp; species confirmed in the field research&nbsp; within&nbsp; this&nbsp; dissertation.&nbsp; Floristic&nbsp; analysis was performed using classical numerical methods, in order&nbsp; to&nbsp; present&nbsp; the&nbsp; most&nbsp; represented&nbsp; families, genera,&nbsp; life&nbsp; forms&nbsp; and&nbsp; chorotypes.&nbsp; Endemic,&nbsp; relict and&nbsp; endangered&nbsp; and&nbsp; invasive&nbsp; species&nbsp; of&nbsp; Sandstone are&nbsp; presented.&nbsp; 16&nbsp; endemic,&nbsp; 22&nbsp; relicts,&nbsp; 49&nbsp; strictly protected, 8 from the Red Data Book of Serbian flora and 54 invasive taxa have been recorded in Deliblato Sands.&nbsp; The&nbsp; dynamics&nbsp; of&nbsp; floristic&nbsp; research&nbsp; is represented&nbsp; by&nbsp; the&nbsp; analysis&nbsp; of&nbsp; literary&nbsp; data&nbsp; and&nbsp; the dynamics&nbsp; of&nbsp; research&nbsp; activities&nbsp; in&nbsp; this&nbsp; area.&nbsp; In accordance with the significant social changes of the area,&nbsp; it&nbsp; is&nbsp; noted&nbsp; that&nbsp; the&nbsp; most&nbsp; significant&nbsp; event&nbsp; was the&nbsp; beginning&nbsp; of&nbsp; afforestation&nbsp; of&nbsp; the&nbsp; Sand.&nbsp; The vegetation&nbsp; overview&nbsp; of the Deliblato&nbsp; Sands presents the&nbsp; most&nbsp; significant&nbsp; vegetation&nbsp; types&nbsp; of&nbsp; the&nbsp; area, provides&nbsp; phytosociological&nbsp; tables&nbsp; of&nbsp; relev&eacute;s&nbsp; takenduring&nbsp; this&nbsp; research,&nbsp; photographs&nbsp; of&nbsp; communities and&nbsp; maps&nbsp; with&nbsp; points&nbsp; where&nbsp; the&nbsp; recordings&nbsp; were taken.&nbsp; In&nbsp; addition&nbsp; to&nbsp; the&nbsp; already&nbsp; known&nbsp; vegetation units,&nbsp; within&nbsp; the&nbsp; vegetation&nbsp; review&nbsp; of&nbsp; the&nbsp; Deliblat Sandstone,&nbsp; three&nbsp; associations&nbsp; of&nbsp; indigenous vegetation&nbsp; and&nbsp; two&nbsp; stands&nbsp; of&nbsp; anthropogenic communities&nbsp; were&nbsp; presented&nbsp; for&nbsp; the&nbsp; first&nbsp; time.&nbsp; In order to solve the problem of classification of sandy vegetation, phytocenological data were collected and analyzed for the whole Republic of Serbia, as well as the&nbsp; entire&nbsp; Pannonian&nbsp; and&nbsp; Pontic&nbsp; basin.&nbsp; In&nbsp; this&nbsp; way, the classification of the psammophytic&nbsp; communities of&nbsp; the&nbsp; Deliblato&nbsp; Sands&nbsp; to&nbsp; the&nbsp; level&nbsp; of&nbsp; subassociations was clarified. The vegetation dynamics of the Deliblato Sands were analyzed&nbsp; by&nbsp; monitoring&nbsp; successive&nbsp; stages&nbsp; of&nbsp; sand and&nbsp; steppe&nbsp; vegetation.&nbsp; Monitoring&nbsp; also&nbsp; included pedological&nbsp; analyzes&nbsp; at&nbsp; sites&nbsp; of&nbsp; different&nbsp; vegetation types.&nbsp; As&nbsp; part&nbsp; of&nbsp; the&nbsp; monitoring&nbsp; of&nbsp; vegetation dynamics,&nbsp; research&nbsp; has&nbsp; been&nbsp; carried&nbsp; out&nbsp; in&nbsp; areas where steppe stands are being revitalized. The results indicate&nbsp; that&nbsp; the&nbsp; revitalization&nbsp; has&nbsp; achieved&nbsp; good results that need to be further directed and corrected in&nbsp; order&nbsp; to&nbsp; achieve&nbsp; optimal&nbsp; conditions&nbsp; for&nbsp; the survival&nbsp; and&nbsp; development&nbsp; of&nbsp; steppe&nbsp; and&nbsp; other vegetation types. The&nbsp; results&nbsp; of&nbsp; this&nbsp; doctoral&nbsp; dissertation&nbsp; provide&nbsp; a good&nbsp; basis&nbsp; for&nbsp; further&nbsp; floristic&nbsp; and&nbsp; vegetation research&nbsp; in&nbsp; the&nbsp; Deliblato&nbsp; sands,&nbsp; as&nbsp; well&nbsp; as&nbsp; other similar natural areas and a significant contribution to the study of the flora and vegetation of Serbia.</p>

Nature-based solutions (NBS) are promising strategies for protecting vulnerable coasts in the context of climate change, utilizing the coastal protection capabilities of natural ecosystems for engineering applications. The ability of coastal marsh vegetation to attenuate wave energy and prevent coastal erosion has been acknowledged for decades, however, consideration for their use in coastal protection strategies is presently limited, particularly in Canada due to a lack of engineering guidelines and limited available research considering region-specific variables. Physical modelling presents a useful tool for investigating the coastal protection function provided by marsh vegetation in a controlled, repeatable environment, which can ultimately inform the design of nature-based coastal protection strategies. To date, such studies have investigated the influence of plant biophysical parameters (stem flexibility, width, and height) and hydrodynamic conditions (wave height, wave period, and plant submergence) on wave attenuation. These studies have used either live vegetation, requiring full-scale wave testing, or surrogate vegetation, which allows simplified testing at either full- or reduced-scale. Overall, live vegetation studies have been limited in the variety of saltmarsh plants considered, with few studies considering plant species native to the Canadian coastline. Several physical modelling studies have been performed using surrogate plants, however, methods of surrogate development for flexible vegetation or reduced-scale testing are not yet well developed. This thesis aims to address knowledge gaps pertaining to the use of marsh vegetation in coastal protection strategies, particularly through the development of experimental methods with both live and surrogate plants. A full-scale flume study with live vegetation was performed to develop fundamental knowledge of wave-vegetation interactions for Spartina alterniflora and Spartina patens, two salt marsh species native to Canada’s Atlantic coast. S. alterniflora was observed to demonstrate a resistance strategy in response to hydrodynamic forcing, versus the avoidance strategy of S. patens, supporting complementary functioning of the two species if utilized together in coastal protection schemes. Observations of plant properties and stem bending from live plant tests were subsequently applied in the development of a small-scale flume study, which examined wave attenuation associated with a downscaled S. alterniflora meadow in the configuration of a “living dyke” structure. Wave damping induced by surrogate vegetation was observed to be minimal for the tested wave conditions (0.073 m < Hm0 < 0.225 m, 2.0 < Tp < 3.2 s, 1:4 scale) and beach slope (1V:20H), with wave height evolution dominated by wave shoaling and breaking. Several methods were considered for modelling the S. alterniflora meadow at reduced scale, and results demonstrated a sensitivity to surrogate diameter but not flexibility. The development of robust experimental methods for investigating the performance of nature-based coastal infrastructure is essential for the establishment of appropriate design conditions. The scale series approach of this thesis supports such methodological advancements and is expected to make preliminary contributions to design guidance on coastal marsh-based NBS and provide critical direction for future studies.

Continuous measurements of the energy and radiation balance were made during the 1991 growing season over a dwarf willow-birch forest located near Churchill, Manitoba. The ecological setting is described in terms of both the nature of the substrate and the morphology and distribution of the plant species. Intensive measurements of stomatal conductance and xylem pressure potential for several species were taken on three fair weather days. These represented a wide range of air temperatures and leaf-to-air vapour pressure deficits and allowed the quantification of the surface-atmosphere interactions. The very dynamic and important role of the vegetation in the evaporative process is illustrated. The willow-birch forest consists of six main species which have colonized the recently emerged coastline. There is a wide range in the plant height, rooting networks, and above-to-below ground plant mass. A mature leaf area index of 0.81 m^2 m^-2 was reached within 15 days after the onset of growth. The substrate consists of a 20 cm moderately saline organic layer situated on top of sand. Soil moisture was high, with at least some of the roots of all plants residing within the saturated zone throughout the growing season. The influence of the vegetation on both the radiation and energy balance is illustrated by partitioning the growing season into growth, mature and senescence periods. A strong relationship between surface albedo and vegetation growth indicates that the canopy is more effective in reflecting than in trapping radiation. As the canopy matures, the addition of transpiration to the overall evaporation dramatically increases the magnitude of the latent heat flux at the expense of the sensible heat flux. A sensitivity analysis indicates that evaporation is highly sensitive to the canopy resistance. The sensitivity of evaporation to canopy resistance, in turn, is a function of the ratio of canopy-to-aerodynamic resistance. Strong seasonal and diurnal trends are shown in the sensitivity of evaporation to net radiation, canopy resistance, and aerodynamic resistance. Diurnal stomatal conductance measurements indicate that some species show a pronounced midday stomatal closure. A conceptual model is developed which attributes this behaviour to differences in the sensitivities to the leaf-to-air vapour pressure deficit. A non-linear boundary line analysis of stomatal conductance indicates species-specific responses to irradiance, air temperature, leaf-to-air vapour pressure deficit, and xylem pressure potential. The results of the boundary line analysis are coupled with a modified version of the Penman-Monteith combination model. The model predicts evaporation accurately when the canopy is mature, and indicates that 80% of the evaporation originates from the plants (transpiration). The model is used to examine the potential effects of species composition and climate change on evaporation. This illustrates the important and variable role that vegetation can play in determining responses to climate change. / Thesis / Master of Science (MSc)

Ziel der Studie war es zu analysieren, inwiefern eine Operation bei Patienten mit einer infektiösen Endokarditis der linksseitigen Nativklappen und keiner weiteren Operationsindikation als einer Vegetationsgröße ≥10mm, das Auftreten von systemischen Embolien, erneuten Endokarditiden und das Langzeitüberleben beeinflussen. Dafür wurden alle Patienten, die zwischen Januar 2000 und Juni 2012 in der Klinik für Kardiologie des Herzzentrums Leipzig mit einer Linksherzendokarditis der Nativklappen und einer Vegetationsgröße ≥10mm behandelt wurden, in ein Register aufgenommen. Alle Patienten mit anderen Operationsindikationen als ihrer Vegetationsgröße wurden ausgeschlossen. Es wurde eine Langzeitkontrolle hinsichtlich definierter klinischer Ereignisse durchgeführt. 71 Patienten wurden in die Studie eingeschlossen. Die mittlere Vegetationsgrößebetrug 17±5mm. 59 Patienten wurden nach einer mittleren Zeit von 5±6 Tagen nach Beginn der Antibiotikatherapie operiert. Die übrigen 12 wurden rein konservativ behandelt. Das mittlere Follow-up erfolgte nach 6,0±2,9 Jahren. Eine chirurgische Behandlungsstrategie war im Vergleich zu rein medikamentöser Therapie mit einer signifikanten Erhöhung der Langzeitmortalität verbunden (p=0,03, Log-rank-Test; unadjustierte Analyse). In einem multivariaten Cox-Regressionsmodell zeigten chirurgische Behandlung, Beteiligung der Mitralklappe, Staphylokokkus aureus-positive Blutkulturen und steigendes Alter einen Trend als unabhängige Beeinflussungsfaktoren der Langzeitmortalität. Ein signifikanter Unterschied zwischen den beiden Gruppen hinsichtlich symptomatischer systemischer Embolien nach Therapiebeginn und Zahl erneuter Endokarditiden bestand nicht. Daher scheint eine operative Behandlung von Patienten mit einer infektiösen Linksherzendokarditis der Nativklappen und großen Vegetationen ohne weitere Operationsindikationen, wie sie aktuell von europäischen und amerikanischen Leitlinien empfohlen wird, möglicherweise mit einer höheren Mortalität verbunden zu sein. Eine kontrollierte randomisierte Studie zur Gegenüberstellung von operativer und konservativer Behandlung dieser Subgruppe von Endokarditispatienten ist deshalb erstrebenswert.

Recent (post-1950s) climate change impacts on society and ecosystems have been recognised globally. However these global impacts are not uniform at regional or local scales. Despite research progress on such scales there are still gaps in the knowledge as to 'what' is happening and 'where'? The goal of this study addresses some of these gaps by analysing climate variability and vegetation response at the furthest south westerly peninsula of the United Kingdom. This research is focused on West Cornwall (South West England) - an area dominated by a strong maritime influence. The first part of this PhD research analysed archive and contemporary instrumental data in order to detect any trends in climate variability. The weather data was retrieved from the Met Office archive for Camborne 1957-2010 and Culdrose 1985-2011 stations; Trengwainton Garden (1940-2010), and from the Royal Cornwall Polytechnic Society, for Falmouth (1880-1952) and Helston (1843-1888). The data showed positive trends in mean annual and maximum temperature with the largest trend magnitude in the 20th and 21st century. Seasonal temperature change varies locally with the highest increase in autumn spring and summer. Precipitation trends were only positive for the 19th century for Helston. Correlation between precipitation data and North Atlantic Oscillation (NAO index) was negative, however the opposite result was detected when the NAO index was correlated with temperatures. Surprisingly, return period analysis showed a decrease in the frequency and intensity of extreme precipitation events post 1975 for Camborne and Trengwainton Garden stations. The second part of this study analysed changes in vegetation distribution in West Cornwall using historical and contemporary vegetation records. Historical vegetation records were used from the Flora of Cornwall collection of herbarium records and contemporary vegetation records which were available online, containing mainly the 'New Atlas of British and Irish flora'. Data sets were geo-referenced using ArcGIS in order to analyse changes in species geographical distribution pre and post-1900. Analysis showed that historical vegetation records can be used to assess any changes in geographic distributions of vegetation. Analysis for the area of West Cornwall showed a loss of range for 18 species, for 6 species this loss was larger than 50% of the area, and there was no change in overall range area for 10 species. Ellenberg values and environmental indicator values showed that they can be used as an indicator of environmental change, showing a decrease in species with lower January temperatures. Analysis also showed an increase in moderate wetter species, where species with extreme low and high precipitation environmental indicator values showed a greater loss. Furthermore species with a higher requirement for light showed a loss as well as species with lower nitrogen values. To analyse the loss of species at the local scale, West Cornwall was divided into three areas (North Border Cells, Central West Cornwall Cells and South Border Cells). The highest loss of 11 species was detected for South Border Cells, where the loss for Central West Cornwall Cells was 6 and for North Border Cells 8 species. It was found that 17 species were experiencing loss on different local sites. For 9 of these 17 species, change at the local scale was different to the national scale change at the individual species level, group level and habitat level. Furthermore, the whole area of West Cornwall lost two species post-1900, with a different loss locally. This showed that species could be protected locally in appropriate microclimate refugia, which will be of benefit for the preservation of regional identity ecosystem services and overall genetic pool of the species.

As fluvial, riparian and floodplain ecosystem functions are recognised for their role supporting fisheries and ecological values, recovery of streamside vegetation is increasingly important in river 'restoration'. Fluvial geomorphology and hydraulic engineering do not yet account well for the role of vegetation in fluvial processes. This research addresses the need for greater understanding of woody riparian vegetation influences on the hydraulics of overbank flow and floodplains sedimentation. Original hypotheses, research design, and data collection were generated by the student to address this gap in knowledge. A soil bioengineering design was constructed on the Mattole River, California, to revegetate the floodplain for better fish rearing habitat. Field data collection was carried out on this unregulated river for two flood events. The sediment samples resulting from a 1.25-year flow permitted the field testing of an hydraulic flume model of vegetation trapping efficiency. From velocity profiles measured during a I5-year storm event, the bed shear stress reduction caused by the vegetation was computed to be approximately 70-90%. A survey conducted in the UK and internationally evaluated from literature, hydraulic researchers and practitioners of river revegetation, the extent of and gaps in knowledge with regard to river bank stabilisation using live vegetation. A flume flow visualisation study simulated the hydraulic behaviour observed on the Mattole floodplain, which enabled characterisation of flow behaviour through a porous filter medium. Results of this research indicate that flexible woody stems have a profound 'calming' effect on overbank flow. These effects are propagated in the downstream direction at least five and as much as ten times the width of the baffle, much further than previously indicated. This research suggests that flexible vegetation is extremely effective in trapping fine (clay) sediments, contrary to general understanding and of importance for fish habitat. For hydraulic reasons, constructed zones of shrubs, such as the siltation baffle, could be spaced further apart than current design practise indicates.

The objective of this research was development and testing of a method for estimating cattle carrying capacities. A series of studies were conducted in developing this method. Range site and vegetation production data were grouped by topographic position and multiple linear regression equations were calculated for predicting vegetation production as a site deviated from the average case of a given range site. Overstory-understory relationships from the literature were adapted into overstory canopy cover classes for predicting understory production and tested on a variety of range sites. Use of these classes produced understory biomass estimates within 13% of measured biomass. Range condition class and understory aspect dominance by forage vs. non-forage species were investigated as estimators of forage value of the understory vegetation. Both were significantly related to amount of forage in the understory. However, understory aspect proved to be a better estimator when individual comparisons were examined. The previous findings, along with Soil Conservation Service range site guides, were used to calculate resource value ratings. Adjustment factors to be applied to the resource value ratings were calculated, using data from the literature, to account for the effects of slope and distance from water on forage utilization by cattle. These resource value ratings and adjustment factors form the basis of the carrying capacity estimation method. Pastures identified as properly utilized were used in testing the method developed. Pastures were mapped for range site, vegetation, slope and water location. Maps were converted to digital form and analyzed using the Map Analysis Package (MAP) computer program (Tomlin, 1975). Construction of a final range site-vegetation-slope-distance from water map, assigning of resource value ratings and adjustment factors, and computation of final carrying capacity estimates were accomplished using MAP. Carrying capacity estimates from the developed method were well correlated to estimates from ocular reconnaissance and area allowable use methods, r = .87 and .97, respectively, and with the actual use (perceived proper use), r = .95. These estimates were accomplished without intensive field sampling. The only information required was range site designation, amount of overstory canopy cover, understory aspect class, percent slope and water location.

No description available.