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Pressure impulses caused by wave impactCox, Simon John January 1998 (has links)
No description available.
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ONTOGENETIC AND MORPHOLOGICAL EFFECTS OF PERSONALITY IN COMMON CARP (CYPRINUS CARPIO)2013 August 1900 (has links)
The field of animal personality has been growing rapidly in the past 10 years, yet relatively little attention has been given to development of personality through ontogeny. To understand the stability of personality traits throughout animal’s life is particularly important as behavioural tendencies are likely to change in response to the different trade-offs animals face at each stage of the life cycle. The purpose of this research was to examine the stability of personality traits in common carp but also to determine whether personality traits can affect production of induced morphological defences in this species.
To investigate the presence of behavioural syndrome and the stability of individual behaviours through ontogeny, common carp were monitored for a period of 10 months. Two different tests were used to investigate cross-situational consistency in behavioural traits: exploration and risk-taking. Juvenile carp were monitored at different time intervals to assess behavioural stability. Finally, morphometric data were collected to examine the link between body morphology and behavioural traits.
No initial cross-situational consistency in behaviours was observed in juvenile common carp. Ranking of behaviour traits was consistent over a period of 14-16 weeks but not when the time interval was longer. Young carp that ranked lowest in both shelter use and activity used shelter significantly more compared to those individuals that ranked highest in use of shelter and activity even after a 10 month period. Development of a deeper body was also associated with the extreme levels of shelter seeking and activity. Fish pre-determined as being “Active” increased their body depth significantly more than did “Passive” fish. To my knowledge, this is the first study directly linking personality traits and change in body morphology in an aquatic species.
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Control of anti-apoptotic and antioxidant pathways in neural cellsMubarak, Bashayer Rashed A. January 2013 (has links)
Oxidative stress is a feature of many chronic neurodegenerative diseases as well as a contributing factor in acute disorders including stroke. Fork head class of transcription factors (Foxos) play a key role in promoting oxidative stress-induced apoptosis in neurons through the upregulation of a number of pro-apoptotic genes. Here I demonstrate that synaptic NMDA receptor activity not only promotes Foxos nuclear exclusion but also suppresses the expression of Foxo1 in a PI3K-dependent fashion. I also found that Foxo1 is in fact, a Foxo target gene and that it is subject to a feed-forward inhibition by synaptic activity, which is thought to result in longerterm suppression of Foxo downstream gene expression than previously thought. The nuclear factor (erythroid 2-related) factor 2 (Nrf2) is another transcription factor involved in oxidative stress and the key regulator of many genes, whose products form important intrinsic antioxidant systems. In the CNS, artificial activation of Nrf2 in astrocytes has been shown to protect nearby neurons from oxidative insults. However, the extent to which Nrf2 in astrocytes could respond to endogenous signals such as mild oxidative stress is less clear. The data presented herein, demonstrate for the first time that endogenous Nrf2 could be activated by mild oxidative stress and that this activation is restricted to astrocytes. Contrary to the established dogma, I found that mild oxidative stress induces the astrocytic Nrf2 pathway in a manner distinct from the classical Keap1 antagonism employed by prototypical Nrf2 inducers. The mechanism was found to involve direct regulation of Nrf2's transactivation properties. Overall these results advance our knowledge of the molecular mechanism(s) associated with the control of endogenous antioxidant defences by physiological signals.
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Protein Bound 3,4-Dihydroxyphenylalanine as a Signal for Enhanced Antioxidant DefencesNelson, Michelle Amy, n/a January 2008 (has links)
Protein-bound 3,4-dihydroxyphenylalanine (PB-DOPA), a long-lived, redox-active product of
protein oxidation, is capable of functioning as both a pro- and anti-oxidant. A number of
in vitro and in vivo studies have demonstrated a toxic, non-toxic or even beneficial effect of
free DOPA, however little investigation has examined the physiological activity of PB-DOPA.
Furthermore, as free DOPA is currently the major treatment available for Parkinson?s disease,
most studies have focused on the effect of DOPA within neurological cells or tissues,
although the presence of PB-DOPA in other locations, for example within atherosclerotic
plaques, suggests that broader research is needed to fully understand the physiological effects
of both free and PB-DOPA.
The hypothesis presented in this thesis is that under physiological conditions, when little
redox active transition metal is available, PB-DOPA can function as a redox signalling
molecule, triggering an enhancement of cellular antioxidant defences, with a potentially
specific role in the regulation of defences targeted against protein oxidation. Physiological
levels of PB-DOPA are very low, however the level on individual proteins can change to a
proportionally large degree during oxidative stress, an appropriate property for a signalling
molecule. In addition, remarkably elevated levels occur in some pathologies, including
atherosclerosis. As an initial and commonly formed product of protein oxidation, PB-DOPA
is well placed for a signalling role, promoting a significant up-regulation of antioxidant
defences in the early stages of oxidative stress, before extensive damage has occurred. As an
initiator of antioxidant defences, PB-DOPA would be potentially useful as a therapeutic for
the treatment of diseases involving oxidative stress or the accumulation of oxidative damage.
The main objective of this thesis was, therefore, to examine the effect of PB-DOPA on the
cellular antioxidant defence system using monocytic and macrophage-like cells, key cells
involved in the formation of atherosclerotic plaques. The incorporation of free DOPA into
protein during protein synthesis, a process previously shown to occur both in vitro and in vivo,
was used to generate PB-DOPA. Neither free nor PB-DOPA were found to be toxic to
monocytic or macrophage-like cells in culture, but rather were both capable of protecting
these cells from oxidative stress. Free DOPA was shown to be capable of directly scavenging
radicals, a process that was thought to be in part responsible for the protection induced during
oxidative stress. The presence of free and PB-DOPA up-regulated the activity of catalase and
NAD(P)H:quinone oxidoreductase, two enzymatic antioxidants, however the activity of
superoxide dismutase and the concentration of oxidised and reduced glutathione were not
affected. Whilst it was thought that PB-DOPA would have a specific effect on the activity of
antioxidant defences targeted against protein oxidation, proteolysis and bulk chaperone
activity were not affected by a combination of free and PB-DOPA. Oxidatively-induced
protein aggregation, however, was inhibited by the presence of free and PB-DOPA,
suggesting that a more specific chaperone regulation may be taking place.
The regulation of gene and protein expression was thought to be one possible mechanism by
which PB-DOPA could function as a signalling molecule. To test this hypothesis, the effect of
free and PB-DOPA on transcription factor activation and protein expression were investigated.
Free and PB-DOPA did not induce the expression or activation of Nrf2, AP-1 or NFJB, three
transcription factors thought to be involved in the expressional regulation of genes involved in
the antioxidant defence system. However, the expression of a number of proteins, including
antioxidants, chaperones and proteins involved in cell cycle progression, were regulated in
monocytic and macrophage-like cells following the administration of free DOPA under
conditions that resulted in either a high or low level of PB-DOPA generation. The regulated
proteins differed between the two conditions, suggesting that the level of PB-DOPA may be a
key factor in determining the specific defences targeted.
The results presented in this thesis support the hypothesis that PB-DOPA can function as a
signalling molecule, triggering an enhancement of cellular antioxidant defences, with a
specific role in the regulation of the chaperone system, a key defence targeted against protein
oxidation. This thesis may provide the basis for the potential use of free or PB-DOPA as a
therapeutic for diseases known to involve oxidative stress or oxidative damage, however more
research will be required to determine if the effects demonstrated in this thesis are also
capable of occurring in vivo.
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Differences in exocuticle thickness in Leucorrhinia dubia (Odonata) larvae from habitats with and without fishOlne, Karin, Flenner, Ida January 2006 (has links)
<p>Many prey species are able to develop different morphological structures as defence against</p><p>for example predators. Some of these structures are induced only by individuals exposed to a</p><p>predator. This phenomenon is called phenotypic plasticity. In this paper we examine whether</p><p>cuticle thickness in Leucorrhinia dubia (Odonata) larvae differed between specimens caught</p><p>in fish containing lakes and fish-free lakes respectively. We measured the thickness of the</p><p>cuticle from four different parts of the larvae; profemur, pronotum, ninth segment sternite and</p><p>ninth segment tergite. Our results showed a significantly thicker exocuticle on profemur in</p><p>larvae with a head width bigger than 4.5 mm caught in lakes with fish. The smaller larvae</p><p>showed a tendency to have thinner exocuticle on profemur in presence of fish. We discuss the</p><p>probability that the differences in exocuticle thickness on profemur could be some kind of</p><p>trade-off situation. The results also showed a tendency among the large larvae; the large</p><p>individuals from lakes containing fish had a slightly thicker exocuticle on pronotum than the</p><p>bigger individuals from fish-free lakes.</p>
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Differences in exocuticle thickness in Leucorrhinia dubia (Odonata) larvae from habitats with and without fishOlne, Karin, Flenner, Ida January 2006 (has links)
Many prey species are able to develop different morphological structures as defence against for example predators. Some of these structures are induced only by individuals exposed to a predator. This phenomenon is called phenotypic plasticity. In this paper we examine whether cuticle thickness in Leucorrhinia dubia (Odonata) larvae differed between specimens caught in fish containing lakes and fish-free lakes respectively. We measured the thickness of the cuticle from four different parts of the larvae; profemur, pronotum, ninth segment sternite and ninth segment tergite. Our results showed a significantly thicker exocuticle on profemur in larvae with a head width bigger than 4.5 mm caught in lakes with fish. The smaller larvae showed a tendency to have thinner exocuticle on profemur in presence of fish. We discuss the probability that the differences in exocuticle thickness on profemur could be some kind of trade-off situation. The results also showed a tendency among the large larvae; the large individuals from lakes containing fish had a slightly thicker exocuticle on pronotum than the bigger individuals from fish-free lakes.
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The Royal Navy, 1922-1930 : the search for a naval policy in an age of re-adjustment.Des Rosiers, Edward Keith. January 1966 (has links)
At the conclusion of the First World War, Great Britain ranked highest among the world's great maritime Powers, with a fleet materially enriched by the wartime construction of over fifteen hundred vessels and a naval establishment edified by its 1914-1918 experience in the use of the new Navy. Consequently, it was not apparent to other than the most astute observer that the Royal Navy had, in fact, reached the pinnacle of its ascendancy. [...]
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The influence of engineering design considerations on species recruitment and succession on coastal defence structuresJackson, Juliette Elizabeth January 2015 (has links)
Engineering design considerations of artificial coastal structures were tested to resemble as far as possible the nearest natural equivalent habitat, ecologically valuable rocky shores, as a potential management option. Coastal areas around the world attract urbanisation but these transitional areas between sea and land are inherently vulnerable to risk of flooding and erosion. Thus hard structures are often built in sensitive coastal environments to defend assets such as property and infrastructure (roads, railways, ports) against rising and stormy seas. The design, construction and maintenance of hard defences should wherever possible incorporate ecological considerations to enhance biodiversity, including maintaining or restoring natural habitats and wild species to ensure favourable conservation status. Artificial habitats are less topographically complex than natural rocky shores, at millimetre scales in terms of surface roughness, centimetre to meter scales for crevices and pools to tens, hundreds and occasionally thousands of meters for variation in tidal height and wave action gradients. The habitat value of design features of an existing seawall and breakwater, such as areas of different slope and orientation, and the presence of crevices and pools, that are analogous to habitat created by topographical features on a natural shore, were demonstrated by their ability to support distinct assemblages of species. X Furthermore, evidence is provided that a greater variation in the type of design features led to a higher species diversity occupying the structure, and included species that would otherwise not be present on the structure. The long term succession on artificial structures and the biodiversity reached on intertidal coastal defence structures is described to inform understanding of timescales over which successional processes operate. As a consequence of succession, artificial structures of large extent eventually resemble natural rocky shores of the same exposure. Increased surface heterogeneity of concrete armour units on Plymouth Breakwater by drilling holes was effective in adding habitat and increasing local species diversity. These can be added at the construction stage or post construction. In a real case study, added recessed pools, holes and surface texture during the construction of a tidal defence sea wall at Shaldon made heterogeneous surfaces to add habitat and influence species diversity, without compromising the engineering function or aesthetics of the structure. This study provides coastal engineers and decision makers with well researched practical design options to inform future construction and maintenance of coastal defence structures that will encourage specific outcomes to mitigate the negative environmental impact of artificial structures and contribute to conservation priorities.
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The Royal Navy, 1922-1930 : the search for a naval policy in an age of re-adjustment.Des Rosiers, Edward Keith. January 1966 (has links)
No description available.
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Stanovení prognózy ústupu břehové čáry zvoleného úseku břehu údolní nádrže / Determining the prognosis retreat of bank line of the selected section of the bank of the dam BrnoDoušková, Zuzana January 2017 (has links)
Master thesis aims to assessment of abrasion on banks of valley reservoir Brno. There was photodocumentation done and current conditions of abraded banks assessed during field survey. There was variables required to detect bottom of brasion cliff and maximal teoretical shift of bank line in the solved location calculated. There was suggested totaly nine types of precaution against other shift of bank line in cross-sections of abraded banks.
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