784 research outputs found
On-road driving studies to understand why drivers behave as they do at regional rail level crossings
No full textImproving safety at rail level crossings is an important part of both road and rail safety strategies. While low in number, crashes between vehicles and trains at level crossings are catastrophic events typically involving multiple fatalities and serious injuries. Advances in driving assessment methods, such as the provision of on-road instrumented test vehicles with eye and head tracking, provide researchers with the opportunity to further understand driver behaviour at such crossings in ways not previously possible. This paper describes a study conducted to further understand the factors that shape driver behaviour at rail level crossings using instrumented vehicles. Twenty-two participants drove an On-Road Test Vehicle (ORTeV) on a predefined route in regional Victoria with a mix of both active (flashing lights with/without boom barriers) and passively controlled (stop, give way) crossings. Data collected included driving performance data, head checks, and interview data to capture driver strategies. The data from an integrated suite of methods demonstrated clearly how behaviour differs at active and passive level crossings, particularly for inexperienced drivers. For example, the head check data clearly show the reliance and expectancies of inexperienced drivers for active warnings even when approaching passively controlled crossings. These studies provide very novel and unique insights into how level crossing design and warnings shape driver behaviour
Crafts in the Southern Mountains
No full textThis article appeared in the 1931, November/December issue of "Handicrafter" magazine. It traces author "P.B."'s travels to various craft centers in the southern Appalachian mountains. Mentioned in the article are Allanstand Cottage Industries, The Spinning Wheel, Clementine Douglas, Winogene Redding, Evelyn Bishop, Mrs. Stone, Blue Ridge Weavers, Penland's Weaving Institute, Penland Weavers and Potters, Crossnore School, Mrs. H. N. Johnson, Pi Beta Phi Fraternity School, and Berea College's Fireside Industries. The author only gives a brief impression of his or her visit to each place. It is likely that author P.B. is Paul Bernat, editor of "Handicrafter" magazine
Physical controls on salmon spawning habitat quality and embryo fitness: an integrated analysis
No full textThe research focusses on the river Lugg – a cross-border catchment and major tributary of the river Wye, the most important Atlantic salmon river in England and Wales. The problem of declining Atlantic salmon populations in the catchment is addressed through investigating recruitment from egg fertilization to the emergent life stage and beyond using multiple field-based and laboratory techniques. The approach adopted is multidisciplinary and addresses the need for holistic approaches to habitat degradation which is increasingly recognised as systemic in nature; often with multiple stressors acting interactively. The initial premise of deleterious fine sediment infiltration into spawning gravels was addressed by a sediment fingerprinting study to ascertain the provenance of infiltrated redd sediment from a range of land-use types. In addition, nine artificial redd sites were constructed and assessed for fine sediment infiltration, intragravel dissolved oxygen levels, intragravel flow velocity and other hyporheic pore water characteristics, in relation to survival to emergence over two field seasons.A study examining the quality of emergent fry was also carried out using fitness tests and individual stress levels. Additionally, a study on long-residence groundwater infiltration into the incubation environment was carried out. The main fine sediment contributor was derived from agricultural sources, particularly during wetter periods. The average contribution of fine sediment from agricultural sources was 60%. Survival ranged from 12% to 70% during the 2008 flood season and from 76% - 93% during the 2009 dry season. Fine sediment mass as a stand-alone index was only weakly correlated with survival but is thought to influence other factors; medium strength correlations of survival with dissolved oxygen, intragravel flow velocity and oxygen supply in particular were observed. Evidence of groundwater-surface water interactions were detected at two of three sites investigated and is proposed as an additional controlling mechanism for embryonic survival in the catchment. Sublethal fitness tests demonstrated variations between cohorts in the 2009 period despite a relatively small range of oxygen concentrations. The results highlight both temporal and spatial variations in spawning habitat quality, which influence not only survival to hatch but also posthatch fitness
Embryonic temperature and the genes regulating myogenesis in teleosts
No full textIn this study, full coding sequences of Atlantic salmon (Salmo salar L.) muscle genes were cloned, including myogenic regulatory factors (MRFs) (myod1c, myog, mrf4, myf5), inhibitors of Myostatin (fst, decorin), markers of myogenic progenitor cell (MPC) proliferation (sox8) and fusion (calpastatin), a marker of slow muscle fibre differentiation (smlc1) and a novel eukaryotic gene involved in regulating growth (cee). Several of these genes were then characterised using a range of experimental and computational analyses with the aim to better understand their role in myogenesis and their evolution in teleosts.
A series of experiments supported previous findings that teleosts have extra copies of many genes relative to tetrapods as a result of a whole genome duplication (WGD) event that occurred some 320-350 Mya. For example, it was shown that genes for myod and fst have duplicated in a common teleost ancestor, but were then specifically lost or retained in different lineages. Furthermore, several characterised Atlantic salmon genes were conserved as paralogues, likely from a later WGD event specific to the salmonid lineage. Phylogenetic reconstruction and comparative genomic approaches were used to characterise the evolution of teleost paralogues within a framework of vertebrate evolution. As a consequence of one experiment, a revised nomenclature for myod genes was proposed that is relevant to all diploid and polyploid vertebrates.
The expression patterns of multiple myogenic genes were also established in Atlantic salmon embryos using specific complementary RNA probes and in situ hybridization. For example, co-ordinated embryonic expression patterns were revealed for six salmon MRFs (myod1a, myod1b, myod1c, myog, mrf4, myf5), as well as markers of distinct MPC populations (pax7, smlc1), providing insight into the regulatory networks governing myogenesis in a tetraploid teleost. Furthermore, it was shown that Atlantic salmon fst1 was expressed concurrently to pax7 in a recently characterised MPC population originating from the anterior domain of the epithelial somite, which is functionally analogous to the amniote dermomyotome. In another experiment, the individual expression domains of three Atlantic salmon myod1 paralogues were shown to together recapitulate the expression of the single myod1 gene in zebrafish, consistent with the partitioning of ancestral cis-acting regulatory elements among salmonid myod1 duplicates. Additionally, the in situ expression of cee a novel and highly conserved eukaryotic gene was revealed for the first time in a vertebrate and was consistent with an important role in development including myogenesis.
Additionally, Atlantic salmon were reared at 2, 5, 8 or 10 ºC solely to a defined embryonic stage, which was just subsequent to the complete pigmentation of the eye. After this time, animals were provided an equal growth opportunity. Remarkably, changing temperature during this short developmental window programmed the growth trajectory throughout larval and adult stages. While 10 and 8 ºC fish were larger than those reared at 2 and 5 ºC at the point of smoltification, strong compensatory growth was subsequently observed. Consequently, after 18 months of on growing, size differences among 5, 8 and 10 ºC fish were not significant, although each group was heavier than 2 ºC fish. Furthermore, significant embryonic-temperature induced differences were observed in the final muscle fibre phenotype, including the number, size distribution and myonuclear density of muscle fibres. A clear optimum for the final muscle fibre number was observed in 5 ºC fish, which was up to 17% greater than other treatments. In a sub-sample of embryos, temperature induced heterochonies were recorded in the expression of some MRFs (myf5, mrf4) but not others (myod1a, myog). These results allowed the proposition of a potential mechanism explaining how temperature can program the muscle phenotype of adult teleosts through modification of the somitic external cell layer, a source of MPCs throughout teleost ontogeny
Effects of non-fish based raw materials on the fish muscle quality of salmonids
No full textSalmonids are considered as fatty fish and a healthy food. They are characterized by a high proportion of n-3 long chain polyunsaturated fatty acids (n-3 LCPUFA). There is
great interest in producing high-quality salmonids with a reduced use of fish-based materials and a challenge to adjust feeds towards more sustainable.
This thesis investigated the effects of sesamin, linseed oil (LO), rapeseed oil (RO),krill oil (KO), krill meal(KM), mussel meal (MM), and zygomycete meal (ZM)(Rhizopus oryzae) on fish performance, fatty acid profiles, carotenoids, cytochrome P450 (CYP450) and, colour properties and oxidation in the white muscle of Atlantic salmon (Salmo salar L), rainbow trout (Oncorhynchus mykiss) and Arctic charr (Salvelinus alpinus).
No negative effects on fish performance were found when KM, KO, MM, ZM and sesamin were included in the fish feeds. The FA profile was modified significantly by
these feed compounds. LO and RO increased the α-linolenic acid (ALA) level and decreased the n-3 LCPUFA portion. Sesamin significantly decreased the ALA level and slightly increased the DHA level in some groups of Atlantic salmon and rainbow trout. Stripped-LO showed different effects on the portion of EPA and ALA compared to the LO group. The sesamin content in fish liver was consistent with its level in feeds, while the content in white muscle was similar across all groups. KO, KM and MM contributed a high portion of n-3 LCPUFA and under 3.5 mg/kg astaxanthin to the white muscle of Arctic charr, enhancing a* value. Some groups with a high level of astaxanthin showed high level of oxidation products (thiobarbituric reactive substances). Sesamin and ZM significantly affected the level or activity of CYP 450.
The results of this thesis reveal the different effects of the non-fish-based materials on the fatty acid profile and colour properties in salmonids, suggesting that these feed compounds can be used to improve fish quality with an optimised formula. Results also indicate that new feed raw materials need further evaluation before the full application in commercial fish feeds
Literature review on the potential effects of electromagnetic fields and subsea noise from marine renewable energy developments on Atlantic salmon, sea trout and European eel. Scottish Natural Heritage Commissioned Report
No full textBackground This report reviews the current state of knowledge with regard to the potential for three fish species of conservation importance, namely Atlantic salmon (Salmo salar), sea trout (Salmo trutta) and European eel (Anguilla anguilla), to be affected by marine renewable energy developments (MRED). The focus is on marine wave and tidal power developments that will generate electricity offshore, which will then be transferred to land by subsea cable. During construction and operation, the marine renewable energy (MRE) devices are expected to cause a number of disturbances to the marine environment including electromagnetic fields (EMF) emissions and subsea sounds (generally referred to as ‘noise'). Such disturbances were assessed to meet the following aims: To determine the current understanding of the effects of EMFs and noise associated with the installation and operation of MREDs, on the behaviour of three species: S. salar, S. trutta and A. anguilla. To determine the gaps in current knowledge and identify research requirements.Main findings The availability and quality of the information on which to base the review was found to be limited with respect to all aspects of the fishes migratory behaviour and activity, both before and after MRE development; this makes it difficult to establish cause and effect. The main findings were: S. salar and A. anguilla can use the earth's magnetic field for orientation and direction finding during migrations. S. trutta juveniles, and close relatives of S. trutta, respond to both the earth's magnetic field and artificial magnetic fields. Current knowledge suggests that EMFs from subsea cables and cabling orientation may interact with migrating eels (and possibly salmonids) if their migration or movement routes take them over the cables, particularly in shallow waters (<20m).The effect, if any, could be a relatively trivial temporary change in swimming direction, or potentially a more serious avoidance response or delay to migration. Whether this will represent a biologically significant effect cannot yet be determined. S. salar, S. trutta and A. anguilla are likely to encounter EMF from subsea cables either during the adult movement phases of life or their early life stages during migration within shallow, coastal waters adjacent to the natal rivers. The subsea noise from MRE devices has not been suitably characterised to determine its acoustic properties and propagation through the coastal waters. MREDs that require pile driving during construction appear to be the most relevant to consider, in addition to the time scale over which pile driving is carried out, for the species under investigation. In the absence of a clear understanding of their response to subsea noise, the specific effects on S. salar, S. trutta and A. anguilla remain very difficult to determine for Scottish waters in relation to tidal and wave power. Based on the studies reviewed, it is suggested that fish that receive high intensity sound pressures (i.e. close proximity to the MRED construction) may be negatively impacted to some degree, whereas those at distances of 100's to 1000's of metres may exhibit behaviour responses, the impact of which is unknown and will be dependent on the received sound. During operation there may be more subtle behavioural effects that should be considered over the life time of the MRED. Whether these effects will represent biologically significant impacts cannot yet be determined. The current assumptions of limited effects are built on an incomplete understanding of how the three species move around their environment and interact with natural and anthropogenic EMF and subsea noise. A number of gaps in understanding exist, principally whether S. salar, S. trutta and A. anguilla respond to the EMF and/or the noise associated with MREDs in Scottish waters. A number of suggestions for specific studies are highlighted in the final section of the report
Sensory and chemical changes in farmed Atlantic salmon ( Salmo salar ) during frozen storage
No full textFarmed Atlantic salmon (Salmo salar) were stored as fillets at -10 and -20 degrees C and whole at -30 degrees C. The most pronounced sensory changes were first recognized by the assessors, when the salmon samples were in the oral cavity, and were significant increases in train oil taste, metal taste, and bitter taste in the fillets. This was shown by mixed model analysis of variance and canonical variates analysis. Volatile lipid peroxidation products such as aldehydes and ketones were identified and quantified in the salmon. For most of the peroxidation products the concentration increased during storage. The content of lipid hydroperoxides and free fatty acids also increased during storage, and the changes were fastest in salmon stored at -10 degrees C. A decrease in highly unsaturated fatty acids was observed in salmon stored at -10 and -20 degrees C. Peroxide values and the content of free fatty acids were shown by a partial least-squares analysis to be the best of the instrumental data in describing the sensory changes
Endoscopic therapy of the sump syndrome
No full textSeventeen consecutive patients with the sump syndrome were treated at the Middlesex Hospital between November 1983 and December 1987. Fifteen were treated primarily by endoscopic sphincterotomy and two primarily by resective surgery because of coincident severe painful chronic pancreatitis. Endoscopic sump clearance was successful in thirteen out of fifteen cases (87%) with no morbidity or mortality. The two endoscopic failures were managed surgically. Follow-up (mean 18 months; range 2-48 months) has shown complete resolution of symptoms in twelve (71%), with mild or moderate ongoing symptoms in the remaining five. All patients with ongoing symptoms after sump clearance had abnormal retrograde pancreatograms at the time of ERCP. Endoscopic sphincterotomy is the treatment of choice for the sump syndrome, with the possible exception of patients with coincident painful severe chronic pancreatitis, who may require pancreatic resection. Indeed, the sump may be a factor in the development and perpetuation of an obstructive chronic pancreatitis, and a trial of endoscopic clearance may be indicated even in these patients. The sump syndrome should no longer be regarded as a major long-term disadvantage of side-to-side biliary bypass, provided that the condition is considered early in those with compatible symptoms after biliary bypass, and appropriate investigation and treatment is instigated
Experimental and computational study of the influence of pre-damage patterns in unreinforced masonry crack propagation due to induced, repeated earthquakes
No full textInduced seismicity in the north of the Netherlands has recently exposed unprepared, unreinforced masonry structures to considerable earthquake risk. While the ultimate-limit state capacity of the structures is vital to assess the individual’s risk, their behavior during more frequent, lighter earthquakes, leading to ‘lighter damage’, has shown to be strongly linked to economic losses and societal unrest. When observing the light damage caused by minor earthquakes, the existing state of the structure appears to be highly relevant for the final damage intensity and configuration: earthquakes that may have otherwise caused no apparent damage, may intensify existing damage. In particular, incipient damage due to settlements is common in the baked-clay and calcium-silicate brick masonry structures of the region.This paper details the study of full-scale laboratory walls, pre-damaged following typical (crack) patterns caused by settlements and tested with quasi-static lateral loads. The aggravation of the damage during a relevant number of load cycles is monitored using full-field digital image correlation. The damage is quantified objectively using a purposely-developed damage parameter.The tests are used (together with previous studies) to further calibrate computational finite element models, which coupled with detailed soil-structure interaction boundary conditions, are then employed to assess a larger number of structural geometries and pre-damaged configurations exposed to (repeated) induced earthquake acceleration histories.Both experimental and computational approaches show that settlement pre-damage in masonry structures increases the likelihood and the amount of further damage. This is more easily observed when some initial, yet limited damage exists and the masonry wall is exposed to moderate earthquake vibrations in the order of 30 millimeters per second.Accepted Author ManuscriptApplied Mechanic
A Critical Look At Mias
No full textIn this report the author brings a figure of the costs that go with the implementation of a landing aid, being a successor to the currently used system ILS. These cost figures should give the reader an insight in the possible costs necessary for the implementation of MIAS. Also a little discussion concerning the market value and the inherent political issues going with it are interwoven in part one of this thesis. Part two deals with the question of how other systems proved their required integrity norms. Especially a closer look at the way ILS System 4000 proved its maturity is given. Two possible methods to decide the service level of the equipment will be described and a list of works where several test specifications are described. Also, a new conception will be introduced, the “AI product”. Part three gives an answer to the following question: there is in the Kalman filter of MIAS the postulation of Gaussian shaped white noise, with a certain variance and on the other hand we want to fetch the stringent ICAO requirements (especially those for the system integrity). Do these two matters go hand in hand or do they conflict each other? Is there a way to fulfil the norms and in the meanwhile make use of the mathematical simplicity of Gaussian shaped white noise? As a reaction on these issues some approaches to adaptive Kalman filtering are described and a new manner of tuning a Kalman filter is set up, based on a system identification algorithm called MOESP.Applied SciencesElectrical EngineeringTelecommunications and Traffic Control Systems Grou
- …
