A series of experiments were conducted during 2005 and 2006 to evaluate five perennial grass species for forage yield and quality, steer performance and grazing capacity, animal intake, plant energy reserves and economic return under grazed conditions. In 1999, two 0.8 ha replicates each of Paddock meadow bromegrass (<i>Bromus riparius</i>Rehm.), Carlton smooth bromegrass (<i>Bromus inermis</i>Leyss.) and AC Knowles hybrid bromegrass (<i>B. riparius</i> x <i>B. inermis</i>) were seeded. In 2003, two 0.8 ha replicates each of AC Goliath crested wheatgrass (<i>Agropyron cristatum </i> (L.) Gaertn.), hybrid bromegrass, and Courtenay tall fescue (<i>Festuca arundinacea </i> Schreb.) were seeded. A long established stand of crested wheatgrass acted as the control pasture. For 2003 established pastures, AC Goliath crested wheatgrass (7515 kg ha-1) had greater (P<0.05) cumulative dry matter yield than hybrid bromegrass (3136 kg ha-1) during the 2005 grazing season. Average (2005-2006) crude protein (CP) was greatest (P<0.05) for hybrid and smooth bromegrass for 1999 established pastures at start and middle of period one. Control pastures had the greatest (P<0.05) neutral detergent fiber (NDF) mid-grazing period. Over 2 years, smooth bromegrass had greater acid detergent fiber (ADF) (P<0.05) than control pastures at the end of the grazing period one. Average (2005-2006) in vitro organic matter digestibility (IVOMD) was greatest for hybrid and meadow bromegrass (P<0.05) at the start of grazing period one. Control pastures (129 g kg-1) had lower CP levels at the start of the 2005-2006 (average) grazing period 1 (P<0.05) compared to species seeded in 2003. Control and hybrid bromegrass pastures had the greatest NDF and ADF levels at the start of grazing period 1 (2005-2006 average) while tall fescue pastures had the lowest (P<0.05) NDF and ADF levels. Over 2 years, control pastures had the lowest IVOMD at start of grazing (P<0.05). In 2006, hybrid and smooth bromegrass had greater etiolated re-growth than control pastures (P<0.05). In 2006, grazed plants seeded in 1999 had greater (P<0.05) etiolated re-growth than ungrazed plants. For 2003 seeded grasses, crested wheatgrass produced greater (P<0.05) etiolated re-growth than tall fescue and control pastures. Average daily gain was similar (P>0.05) for all 1999 and 2003 seeded grasses. Overall, bromegrasses seeded in 1999 produced greater animal grazing days (AGD) than control pastures (P<0.05). Total beef production (TBP) was greater (P<0.05) for hybrid and meadow bromegrass compared to the control. All species seeded in 2003 produced greater AGD (P<0.05) compared to the control. Crested wheatgrass produced greater (P<0.05) TBP than the control over both years of the study. The C33:C32 alkane ratio estimated greater DMI (P<0.05) for hybrid bromegrass (9.9 kg d-1) and control pastures (9.6 kg d-1) compared to crested wheatgrass (6.8 kg d-1) or tall fescue (6.8 kg d-1) during period 1 in 2006. Over 2 years, net return to labor, equity and personal draw was greater (P<0.05) for hybrid bromegrass ($91.24 ha-1) compared to the control (-$54.32 ha-1). For 2003 seeded pastures, all pastures generated positive returns over 2 years. Crested wheatgrass ($92.49 ha-1) had greater net return than control pastures (-$54.32 ha-1) (P<0.05). Finally, the results of this grazing study indicate beef producers can manage these grasses during the summer grazing season and maintain high levels of animal performance and pasture production. This study has demonstrated that bromegrasses, crested wheatgrass and tall fescue could work well in a complementary grazing system.

‘FIELD WORKS’ explores landscape experiences that were once common to the tall grass prairie region of Manitoba. The route through this project winds in and out of urban surfaces to reveal memories embedded in the land. It documents forgotten and dormant prairie events so that they might be woven back into the fabric of the city. The purpose of this project is to transfer explored and speculative experience into a physical route through the urban prairie landscape. It is an effort to expose the layers clinging to physical memories rooted in the prairie. / May 2007

A series of experiments were conducted during 2005 and 2006 to evaluate five perennial grass species for forage yield and quality, steer performance and grazing capacity, animal intake, plant energy reserves and economic return under grazed conditions. In 1999, two 0.8 ha replicates each of Paddock meadow bromegrass (<i>Bromus riparius</i>Rehm.), Carlton smooth bromegrass (<i>Bromus inermis</i>Leyss.) and AC Knowles hybrid bromegrass (<i>B. riparius</i> x <i>B. inermis</i>) were seeded. In 2003, two 0.8 ha replicates each of AC Goliath crested wheatgrass (<i>Agropyron cristatum </i> (L.) Gaertn.), hybrid bromegrass, and Courtenay tall fescue (<i>Festuca arundinacea </i> Schreb.) were seeded. A long established stand of crested wheatgrass acted as the control pasture. For 2003 established pastures, AC Goliath crested wheatgrass (7515 kg ha-1) had greater (P<0.05) cumulative dry matter yield than hybrid bromegrass (3136 kg ha-1) during the 2005 grazing season. Average (2005-2006) crude protein (CP) was greatest (P<0.05) for hybrid and smooth bromegrass for 1999 established pastures at start and middle of period one. Control pastures had the greatest (P<0.05) neutral detergent fiber (NDF) mid-grazing period. Over 2 years, smooth bromegrass had greater acid detergent fiber (ADF) (P<0.05) than control pastures at the end of the grazing period one. Average (2005-2006) in vitro organic matter digestibility (IVOMD) was greatest for hybrid and meadow bromegrass (P<0.05) at the start of grazing period one. Control pastures (129 g kg-1) had lower CP levels at the start of the 2005-2006 (average) grazing period 1 (P<0.05) compared to species seeded in 2003. Control and hybrid bromegrass pastures had the greatest NDF and ADF levels at the start of grazing period 1 (2005-2006 average) while tall fescue pastures had the lowest (P<0.05) NDF and ADF levels. Over 2 years, control pastures had the lowest IVOMD at start of grazing (P<0.05). In 2006, hybrid and smooth bromegrass had greater etiolated re-growth than control pastures (P<0.05). In 2006, grazed plants seeded in 1999 had greater (P<0.05) etiolated re-growth than ungrazed plants. For 2003 seeded grasses, crested wheatgrass produced greater (P<0.05) etiolated re-growth than tall fescue and control pastures. Average daily gain was similar (P>0.05) for all 1999 and 2003 seeded grasses. Overall, bromegrasses seeded in 1999 produced greater animal grazing days (AGD) than control pastures (P<0.05). Total beef production (TBP) was greater (P<0.05) for hybrid and meadow bromegrass compared to the control. All species seeded in 2003 produced greater AGD (P<0.05) compared to the control. Crested wheatgrass produced greater (P<0.05) TBP than the control over both years of the study. The C33:C32 alkane ratio estimated greater DMI (P<0.05) for hybrid bromegrass (9.9 kg d-1) and control pastures (9.6 kg d-1) compared to crested wheatgrass (6.8 kg d-1) or tall fescue (6.8 kg d-1) during period 1 in 2006. Over 2 years, net return to labor, equity and personal draw was greater (P<0.05) for hybrid bromegrass ($91.24 ha-1) compared to the control (-$54.32 ha-1). For 2003 seeded pastures, all pastures generated positive returns over 2 years. Crested wheatgrass ($92.49 ha-1) had greater net return than control pastures (-$54.32 ha-1) (P<0.05). Finally, the results of this grazing study indicate beef producers can manage these grasses during the summer grazing season and maintain high levels of animal performance and pasture production. This study has demonstrated that bromegrasses, crested wheatgrass and tall fescue could work well in a complementary grazing system.

No description available.

Since submerged macrophytes are a key primary producer of shallow lakes and are sensitive to environmental changes, macrofossils of them can be used in investigations of past environmental conditions, to infer human introduced environmental impacts (e.g. eutrophication) and to determine past macrophyte communities. The present study includes twenty six shallow lakes, which were chosen along a latitudinal gradient ranging from the North (41&deg / 52&acute / N, 27&deg / 58&acute / E) to the South (37&deg / 06&acute / N, 29&deg / 36&acute / E) in Turkey. Sampling for environmental variables and sediment was carried out using a snap-shot sampling protocol (developed within the framework of the EU FP6 project &lsquo / Eurolimpacs&rsquo / ) during the summers of three consecutive years (2006-2008). Surface sediment, short core and long core samples were retrieved from the lakes. The aims of this study were i. to compare the surface sediment plant macrofossils with present day macrophyte taxa of the lakes, ii. to determine the environmental variables potentially influencing the temporal changes in macrophyte communities, and iii. to assess vegetation community dynamics in dated short and long cores. Comparison of plant macrofossil assemblages in surface sediment with present day macrophyte coverage revealed that approximately 41% of the modern taxa were represented among the surface sediment macrofossils. Redundancy analysis (RDA) was carried out for surface macrofossil data with corresponding environmental data. RDA revealed relation of plant species and environmental variables (e.g. Salinity and Najas marina L.). Changes in plant species assemblages in short and long cores from eight lakes chosen along a latitudinal gradient ranging from North to South Turkey is discussed in relation to the RDA results.

Texte remanié de: Habilitationsschrift--Philosophische Fakultät--München--Ludwig-Maximilians-Universität, 2004. / Bibliogr. p. 313-332.

Thesis (Ph. D.)--Institute of Paper Chemistry, 1979. / Bibliography: leaves 138-142.

Thesis (M.S.W.)--University of Hong Kong, 1983.

published_or_final_version / Urban Design / Master / Master of Urban Design

Σκοπός αυτής της διπλωματικής εργασίας, είναι να παραθέσει τους τρόπους με τους οποίους προστατεύουμε ψηλά κτίρια - κατασκευές από κεραυνικά πλήγματα. Η προστασία των ψηλών κατασκευών είναι εντελώς διαφορετική από την προστασία χαμηλότερων κατασκευών αφού παύουν να ισχύουν οι κανόνες και τα επίπεδα προστασίας για κτίρια μέχρι 60m που ισχύουν στους διεθνείς οργανισμούς και τον Ε.Λ.Ο.Τ. Από τα 60m και πάνω οι συνθήκες είναι πολύ διαφορετικές, γι αυτό το λόγο γίνεται επεξήγηση για όλους τους παράγοντες που επηρεάζουν μια ψηλή κατασκευή όσον αφορά την προστασία της με τη γειωμένη μεταλλική ράβδο του αλεξικέραυνου του Franklin. Επίσης, μέσω της εφαρμοσμένης υπολογιστικής εξομοίωσης γίνεται προσπάθεια να βρεθεί η απόσταση διάσπασης ( stricking distance ) δηλαδή η ακτίνα προστασίας που καλύπτει μια κατασκευή με μέθοδο προστασίας την ακίδα Franklin. Τα αποτελέσματα και τα συμπεράσματα συγκρίνονται με πειραματικές μετρήσεις που έγιναν σε εργαστήριο. Παρακάτω παρατίθενται τα περιεχόμενα του κάθε κεφαλαίου της εν λόγω εργασίας. Στο 2ο κεφάλαιο γίνεται πλήρης ανάλυση για τη φυσική των κεραυνών. Γίνεται κατηγοριοποίηση των φάσεων που εξελίσσονται σε κεραυνό από τη γη μέχρι τα σύννεφα και παρουσιάζεται ο μηχανισμός των ατμοσφαιρικών εκκενώσεων. Ακόμα, γίνεται εξήγηση για τους ανοδικούς συνδετικούς οχετούς και την απόσταση διάσπασης από τα’ αλεξικέραυνα και τους οχετούς καθόδου. Στο 3ο κεφάλαιο αναπτύσσονται οι βασικοί παράμετροι και εξισώσεις που ισχύουν για ψηλά κτίρια όπως η ελάχιστη ακτίνα προστασίας-απόσταση διάσπασης, η ισοδύναμη επιφάνεια, η πιθανότητα της ελάχιστης ακτίνας διάσπασης και ανοδικών leader από τέτοια ψηλά κτίρια, ο επηρεασμός της ακίδας προστασίας και απόστασης διάσπασης από θετικούς κεραυνούς, τη σχέση που έχουν τα ψηλά κτίρια με την απόσταση διάσπασης και την επίδραση των γειτονικών κατασκευών. Ακολούθως, γίνεται περιγραφή της μεθόδου CVM για το χειρισμό ψηλών κατασκευών με επίπεδα και γωνίες προστασίας και πίνακες ρίσκου βασισμένα σε στατιστικές από κεραυνούς. Μετέπειτα, βλέπουμε πως επηρεάζεται η απόσταση διάσπασης από τη γεωμετρία της κατασκευής, από την γεωμετρία της ακίδας προστασίας Franklin, αλλά και από τη βέλτιστη ακτίνα κορυφής της ακίδας προστασίας Franklin. Στο 4ο κεφάλαιο γίνεται προσπάθεια να προσδιορίσουμε τη ζώνη προστασίας με τη χρήση υπολογιστικού μοντέλου. Αρχικά, αναφέρουμε κάποια στοχαστικά μοντέλα διάσπασης διηλεκτρικών. Μετά προχωρούμε στην περιγραφή με λεπτομέρεια των υπολογιστικών εξομοιώσεων που πραγματοποιήσαμε και την τακτική επεξεργασίας τους. Ακολούθως, προσδιορίσαμε τη ζώνη προστασίας των εξομοιώσεων για ύψος ακίδας 80cm και 100cm με γραμμικές εξισώσεις από προσαρμογή των μετρήσεων στις γραφικές παραστάσεις που δείχνουμε και αντίστοιχα στοιχεία για τις δυο ακίδες με αύξηση της τάσης 10%. Στο τέλος γίνεται επεξεργασία των δεδομένων και συγκρίνουμε τις μετρήσεις που βρήκαμε μεταξύ τους αλλά και με άλλους μελετητές. Αναφέρουμε τα αποτελέσματα της διεξαγωγής των υπολογιστικών εξομοιώσεων και τα συμπεράσματα. Στο 5ο κεφάλαιο κάνουμε ανακεφαλαίωση των θεωρητικών στοιχείων που ισχύουν για τις ψηλές κατασκευές και γενική συζήτηση. Επίσης εξάγονται χρήσιμα συμπεράσματα από τις υπολογιστικές εξομοιώσεις που πραγματοποιήθηκαν τόσο για την απόσταση διάσπασης όσο και για τις εξομοιώσεις που πραγματοποιήσαμε / The purpose of this project is to set out the possible ways that protect tall structures from lightning strikes. The protection of the tall structures is a completely different task from the protection of the shorter structures. That is because the rules and the protection levels applied by National Organizations (International Committee) and Ε.Λ.Ο.Τ. that concern structures to 60 meters, cease to exist in the case of taller structures. Concerning the structures that are taller than 60 meters the protection circumstances are very different from those of shorter structures. That is why this thesis explain all the factors that affect a tall structure, as far as its protection with the “Franklin Rod” is concerned. Furthermore, through computer simulation the author attempted to determine the striking distance, which is the protection radius that covers a structure, by utilizing as a method of protection the Franklin Rod. The results and conclusions that arose were compared with experimental measurements that took place in the lab. Below, the content of each chapter of this thesis is described. In the second chapter it is attempted a thorough analysis of the nature of lightning. Then there is a categorization of the phases that evolve to a lightning, from the ground to the clouds. The mechanism of atmospheric evacuation is also presented. Moreover, the upward connection leaders, the striking distance from the lightning rods and the downward leaders are described and explained. In the third chapter, the basic parameters and equations that apply to tall buildings are described. Some of these parameters are the attractive radius, the striking distance, the equivalent exposure area, the weighted average attractive area, the upward leaders from such tall buildings, the influence of the Franklin rod, the striking distance from positive flashes, the relation that the tall structures have with the striking distance and finally the influence of the surrounding structures. In addition, the CVM (Collection Volume Method) is described which deals with tall structures by utilizing protection levels and derating angles and risk analysis tables based on lightning’s statistics. Moreover, we see how the striking distance is affected by the structure geometry, by the geometry of the Franklin rod but also by the optimum tip radius of Franklin rod. In the fourth chapter the author attempted to determine the protection zone by using a computer model. Firstly, some stochastic models of dielectric breakdown are described. Furthermore, a detailed description of the computer simulations that we accomplished and the method of processing them are described. Moreover, the author determined the protection zone of the simulations for rod height: 80cm and 100cm with linear equations, by using measurement fitting to graphs where we show the respective elements for the two rods by raising 10 % of the Volts of the measurement. In the end, the data were processed and a comparison of this thesis’ findings and that of other authors were compared. The author also describes the results of the computer simulations and the conclusions that arose. In the fifth chapter the author revised the theoretical elements that apply to the tall structures and makes reflections on the findings. Moreover, useful conclusions arise from computer simulations that took place as far as the striking distance as well as the simulation is concerned.