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1
Staniland, Iain John. "The feeding ecology and behaviour of whiting (Merlangius merlangus L.)." Thesis, University of Leicester, 1995. http://hdl.handle.net/2381/34239.
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The development of multispecies fisheries models has led to a need for improved information on the diet composition and consumption rates of fish. This study was an attempt to investigate the feeding ecology of whiting, with an emphasis on how the fishes' behaviour might influence its diet. Analysing the stomach contents of North Sea whiting, found that as whiting increased in size they switched from a crustacean, to a fish dominated diet, and the average size of prey eaten increased. Smaller trawl caught whiting were found to have a higher instance of regurgitation. The whiting appeared to be exploiting one prey species in an area. The majority of fish stomachs sampled at a station contained the same prey type. Studies showed that sandeels were evacuated from the stomachs of whiting at a higher rate than prawns. When fed in combination the evacuation rate of sandeels increased, and the rate of prawns decreased. It was postulated that these evacuation rate changes could be because of stomach packing and/or the prawns' abrasive exoskeleton. Video analysis of whiting feeding on shrimp studied the effects of changing the predator to prey size ratio, stomach fullness and experience. As the predator to prey size ratio increased the handling time decreased, and probability of successfully eating a shrimp increased. As the fish gut filled up the probability of a strike being successful decreased and handling time increased. With increasing experience the hunting sequence of the fish became simplified and the probability of a strike being successful increased. Results from the video analysis were used to develop a stochastic dynamic program of whiting feeding. The program was used to model the optimal prey choices of whiting feeding on two sizes of shrimp. In the model the probability of success was found to be the most important factor in determining the optimal shrimp size. The time spent in handling the shrimp was also found to be important. It was concluded that a more behavioural approach could help in understanding why fish eat what they do and aid investigations into the problems of fish species interactions.
2
Long, Jacqueline. "Whiting Events Off Southwest Florida: Remote Sensing and Field Observations." Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6535.
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“Whiting” is a term used to describe a sharply defined patch of water that contains high levels of suspended, fine-grained calcium carbonate (CaCO3). These features are named for their bright (at times white) appearance when compared to surrounding waters, and have been found to occur globally, persisting for multiple consecutive days. Although whitings have been widely studied using chemical, biological, geological, and physical techniques, there has been little effort to document their spatio-temporal distributions in a systematic way, not to mention the lack of consensus on what generates whitings and allows them to persist for days to weeks at a time. In particular, although fishermen and aircraft pilots have reported whiting-like features off southwest Florida (e.g., a sighting off the Ten Thousand Islands was reported on October 29, 2013), there has been no targeted study on these features in this area. Therefore, the objective of this study is two fold: 1) to document the spatial-temporal distributions of whitings in southwest Florida (SWFL) coastal waters from 2003 through 2015 using satellite imagery to study how their occurrence is related to several environmental variables and 2) to conduct field and laboratory measurements to determine the particle composition and water characteristics in and outside the whiting features.
To achieve objective one, a multi-year time series from 2003 through 2015 was developed over SWFL using Moderate Resolution Imaging Spectroradiometer (MODIS) observations. Customized processing was used in order to removed clouds and other artifacts and to delineate the surface whiting features. From this, statistics and distribution maps of whiting occurrence were generated. Annual mean whiting coverage peaked in 2011 (11 km2), when whiting reached a maximum daily visible coverage of 92 km2 on February 23. For the entire time series, the highest daily coverage observed was 126 km2 on December 6, 2008. Over all, whitings had higher spatial coverage during the spring and autumn, with 88% of all whiting coverage occurring within 40 km of the coastline. Images of average seasonal spatial distributions showed that over 90% of whitings located between 40 and 70 km of shore occurred specifically during the winter and autumn. A multivariate linear regression was performed, which found little to no correlation between annual whiting coverage and environmental factors such as sea surface temperature (SST), wind, and river discharge. This analysis was also applied to spatial distributions of whiting events within and outside of 20 km and 40 km from shore. The only statistically significant result was that of SST, as well as SST with river discharge and whiting events distributed more than 20 km from shore.
In order to accomplish objective two, several field campaigns were conducted to collect in-situ data and water samples of pre-, post-, and occurring whiting event conditions to provide information on composition, driving forces, and variables that cannot be derived via satellites. Samples were collected for taxonomic identification, chemical analysis, bottom sediment grain size fractionation, in-situ remote sensing reflectance (Rrs), particle backscattering (bbp), chlorophyll-a concentration ([chl-a]), particulate absorption (ap), and gelbstoff (otherwise known as color dissolved organic matter, or CDOM) absorption (ag). Taxonomic identification of marine phytoplankton within whiting water revealed the presence of a dominant, small (<5 >μm), centric diatom species during a sampled whiting event. Through the use of scanning electron microscopy (SEM), these were identified as Thalassiosira sp. Amorphous to fully formed crystals of calcium carbonate were present, attached to cells of Thalassiosira sp., localized to the girdle bands. All other diatom species were devoid of similar growths. In comparing the waters within a whiting area to outside waters, no significant differences were found in ap, ag, nor [chl-a]. The carbonate parameters of whiting water differed from outside water, however due to low sample numbers these results are inconclusive. Average backscattering was twice as high within whiting waters compared to non-whiting water, and measured in-situ Rrs was higher at all wavelengths (400 – 700 nm) within whiting water, with a spectral shape similar to outside waters.
Overall, this is the first time that SWFL whiting events have been characterized systematically using satellite imagery, field and laboratory as well as meteorological data to diagnose whiting causes and maintenance mechanisms. Although these results are inconclusive, they add new information to the existing literature on this phenomenon.
3
Norris, Andrew J. "Sensory modalities, plasticity and prey choice in three sympatric species of whiting (Pisces:Sillaginidae) /." St. Lucia, Qld, 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17866.pdf.
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4
Demain, Dorota K. "Settlement ecology of juvenile cod Gadus morhua, haddock Melanogrammus aeglefinus and whiting Merlangius merlangus." Thesis, University of Aberdeen, 2010. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=158304.
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Cod, haddock and whiting are among the most economically important species in the Scottish demersal fishery. Juvenile settlement, the transition from pelagic to demersal habitat, has been identified as an important milestone for these species, but there is insufficient knowledge and data about this life stage. It is believed that the period of settlement has an impact on recruitment success, as important density-dependent processes may take place, such as competition for suitable substrate, refuge or prey. Also, knowledge of settlement timing and duration is relevant to understanding population connectivity and thus to the development of successful conservation measures. Sampling was conducted between April and August 2004, June and September 2005 and June and July 2006 at an inshore site off the east coast of Scotland. Over 4000 0- group cod, haddock and whiting were collected. Comprehensive morphometric and dietary analyses of the samples were carried out, followed by statistical analysis of the data. The results suggested clear differences in the patterns of settlement between the different species. Initially juvenile haddock favoured deeper, further offshore locations, while cod occupied shallower, inshore waters. Whiting settled much later in the season and over protracted period of time. Furthermore, cod showed an affinity for structured habitat, while haddock and whiting were found only over sand. The results also showed that the transition from the pelagic to the demersal habitat was associated with clear and progressive changes in the prey composition of the juvenile fish. The results also showed temporal, spatial and dietary niche segregation of settling juveniles, which is expected to reduce competition for resources and increase the potential for settlement success.
5
Ghaffar, Mazlan Abd. "Food consumption patterns and dietary digestibility of whiting (Merlangius merlangus L.) fed in laboratory conditions." Thesis, Bangor University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327516.
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Zheng, Xiaohong. "Analysis of cod, haddock and whiting distribution in UK waters in relation to environmental variables." Thesis, University of Aberdeen, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395051.
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This study systematically analysed the spatial distribution of cod (<I>Gadus morhua, </I>[Linnaeus, 1758]), haddock (<I>Melanogrammus aeglefinus, </I>[Linnaeus, 1758]) and whiting (<I>Merlangius merlangus</I>, [Linnaeus, 1758]) in UK waters, with particular reference to the North Sea and west coast of Scotland, in relation to environmental variables: sea surface temperature (SST), sea bottom temperature (SBT) and depth using a combination of qualitative (geographic information systems) and quantitative (statistics) methods. Fish abundance data were derived from both survey and fisheries records. The analysis showed: 1. There is a great heterogeneity in spatial and temporal (seasonal) distribution of whiting. The spatial distribution of whiting in winter is related to age, as well as to depth and to spatial patterns of SST at the same time. The area (within the northern North Sea) of highest whiting abundance (derived from fishery data), and the largest seasonal change in the abundance, corresponds to the area of highest survey catch rates for older (>2 years) whiting in winter, a particular spatial pattern of SST in winter and water depths of 100-200 m. 2. Generalised additive models (GAMs) fitted to whiting abundance (derived from fishery data) in the northern North Sea in relation to SST, SBT and depth showed marked seasonal changes in the spatial relationships between whiting abundance and these environmental variables. In the northern North Sea, SST apparently has important influence on the spatial distribution of whiting, especially during winter and spring (from December to April): where the water is relatively warm (reflected in SST), whiting abundance is relatively high. In summer, this relationship disappears. The inter-annual changes in the strength of the warmness in winter and spring seem to have effect on the inter-annual changes of whiting abundance at 0-2 years lag time. The relatively warm areas in winter and spring in the northern North Sea result partially from the Atlantic current. SST acts as an indicator of the effect of Atlantic currents on local waters.
7
Burgess, J. E., and n/a. "Long term evaluations of the effects of Irlen tinted lenses on academic and related skills." University of Canberra. Education, 1990. http://erl.canberra.edu.au./public/adt-AUC20060622.105432.
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This survey research systematically collects
Information on the long term effects of Irlen tinted
lenses, from a specific diagnosed scotopic sensitive
population. The survey used is based on Whiting's
survey (1988), with variations and extensions made to
increase information attained. Although the main focus
of the survey is reading and related academic skills,
other areas presenting new directions for further
research, have also been included. 306 diagnosed
scotopic sensitive Individuals, who had been using
prescribed Irlen tinted lenses for a minimum of six
months, were surveyed. 82.8 percent of the respondents
indicated that they (or their child) had experienced
great benefits from wearing Irlen tinted lenses. 70.1
percent Indicated that the greatest benefit had been in
the area of reading. Cross-tabulations were made with
length of time wearing the lenses, gender, and whether
the respondent was filling in the questionnaire for
themselves or for their child. The results of this
descriptive research support Whiting's (1988), earlier
findings. A review of the available literature and the
Implications of these findings are discussed.
8
Hadfield, Amelia. "Stages of Englishness, English national identity in the plays of T. S. Eliot and John Whiting, 1945-1954." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0011/MQ36358.pdf.
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Burns, Neil M. "Distribution and demographic connectivity in whiting (Merlangius merlangus) : a novel approach using otolith trace elements in continuous assignment." Thesis, University of Glasgow, 2018. http://theses.gla.ac.uk/9126/.
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Seyhan, Kadir. "Gastric emptying, food consumption and ecological impact of whiting, Merlangius merlangus (L.) in the eastern Irish Sea marine ecosystem." Thesis, Bangor University, 1994. http://e.bangor.ac.uk/4295/.
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Gastric emptying of Sprattus sprattus and Arenicola spp. (gastric lavage) and formulated pellets (X-Ray studies) was investigated in a range of sizes of whiting, Merlangius merlangus fed different meal sizes at different temperatures. Emptying of indigestible solids, barium sulphate spheroids and ballotini were also studied. Additionally stomach contents of whiting sampled from Red Wharf Bay, Eastern Anglesey, UK. were analysed to determine diet composition, diel feeding periodicity and feeding strategy of whiting. Daily and total annual intake of main prey taxa, sprat, sandeel and crab, were estimated. Finally feeding behaviour of whiting in captivity was monitored. With respect to the studies conducted under laboratory conditions, it was found that gastric emptying is best described by a linear function. The results indicated significant changes in gastric emptying rates with both prey type and size. The seasonal change in temperature did not yield a significant change in gastric emptying rate. Increase in diet surface area also did not alter the gastric emptying rate significantly. The results have also shown that in continuously- feeding whiting gastric emptying is affected by the second meal such that the arrival of the second meal is accompanied by rapid emptying of a small fraction of the first meal. Despite difficulties encountered with individual variation among whiting of similar size held under similar conditions, gastric emptying times (GET) for both natural food and formulated pellets can be adequately predicted by the equations: GET = 126.47 W -0.111 g 0.26 e -0.068T for the natural food, GET = 6.6 e -0.09T + 2.48 W0.566 e -0.044T for the formulated pellets; where W is the fish weight (g), S is the meal size (g) and T is the temperature (°C) suggesting that a similar meal size of formulated pellet is emptied faster than natural food, Sprattus sprattus. This was interpreted as evidence that natural diets may reflect a combination of 2 factors (a) the relative size of stimulation to the stomach (% distension) and (b) the existence of protective, fibrous skin which resists digestion. Barium sulphate spheroids of diameter 1 mm (ca 20 per g food) and ballotini of diameter 0.029- 0.049 mm (60-100 per 1.58g) were selectively retained by the whiting stomach, suggesting that these indigestible materials can not be used in gastric emptying studies in whiting. Under laboratory conditions with continuous food availability, medium size whiting (155.25±27.98 g) consumed 5.29 g sprat corresponding to 3.41 %bw (approximately 3 sprat, 1.88g each) at 14 °C. The return of appetite after a single meal was found to follow the gastric emptying curve closely. However if food is not offered directly, but made available through demand feeding, the whiting feed rhythmically (every 21 hours), under these conditions it was estimated that feeding activity returns when the stomach is 40 % full. It wa§ found that, in the wild, whiting prefer fish (Sprattus sprattus and Ammodytes spp. ) and crustaceans and only turn to the polychaetes as a third option, even when they are readily available, when preferred food is scarce. The availability of prey was found to be the main criterion in whiting feeding strategy. In March fish were dominant for most whiting, in August and September/October however, Liocarcinus spp. and Corystes cassivelaunus were the main prey items found in whiting stomach reflecting the availability of these prey species. A highly correlated relationship was found between predator (whiting) and prey (sandeel) length, however this was not noticed for sprat; whiting prey on sprat regardless of its length. An increase in feeding intensity was observed in the morning (August), in the evening (September/October), or at both times, crepuscular feeding pattern, (March). However, when feeding behaviour was investigated under laboratory conditions it was found that whiting is mainly a day time feeder with a slight increase in the morning and in the evening, but some feeding also occurs at night. Additionally a strong tendency was found for crustaceans to be found in fish captured during the daylight hours and fish at night in August and September/October. A linear model to estimate food consumption from the field samples was developed. F= (S2-S1) + 1.5 K T, where S2 and SI are average stomach contents at time tI and t2, K is the gastric emptying rate (gh-1) and T is temperature (°C). The average recruited whiting stock in the area of approximately 150 km2 in Red Wharf Bay was estimated to be 129,000 with a total biomass of 22 tonnes. It was estimated that young whiting (groups 0+ to 3+ years) in Red Wharf Bay eat between 1.29 and 6.57 g day-1 in February. By August, when temperature has maximised, these values increase by approximately 70-80 %. Daily intake of sprat, sandeel and crab was estimated to be 0.41,0.14 and 0.14 g for the 0+ group. This was increased to 0.70,0.80 and 0.94 g by the age of 4. On a daily basis the long-term average of the amount of sprat, sandeel and crab consumed were estimated to be 820, 370 and 520 g/km2/day respectively. Total food consumption per year by the recruited whiting stock in the area studied however was 44.8 tonnes of sprat (approximately 11.5 million sprats), 20 tonnes of sandeel and 28.5 tonnes of crab. These figures were compared with the available data from the North Sea as well as from other parts of the Irish Sea and it was concluded that whiting in the Irish Sea eat more than they do in the North Sea.
11
Langsdale, James R. M. "Developmental changes in opacity and visibility of larval Atlantic herring, Clupea harengus L., and their vulnerability to visual predation by whiting, Merlangius merlangus L." Thesis, University of Aberdeen, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333441.
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Features associated with the visibility of larval herring, <i>Clupea harengus</i>, to predators were investigated in the laboratory using larvae reared from artificially fertilised eggs. Herring larvae were reared up to the point at which they metamorphosed into juveniles. Photography and image analysis were used to measure the relative sizes of opaque structures. Lateral body area increased with body length anisometrically (exponent 2.62) and eye area increased at a similar rate (exponent 2.57), but the opaque pigmented lateral area increased as length<SUP>4.41</SUP>. The lateral area of the full gut increased with length<SUP>3.04</SUP>, the proportional increase in opacity resulting from feeding decreasing with body size. Under anaesthetic, larger larvae increased the dispersion of their melanin whereas smaller larvae contracted their melanophores. Herring larvae expanded their melanophores when confined near a black background; in white surroundings they contracted them by up to 90&37. At ecologically realistic intensities, changes in downwelling light did not affect melanophore state but the introduction of sidewelling light had a significant influence when it reached a threshold intensity. Vulnerability to predation by whiting, <i>Merlangius merlangus</i>, was tested. Larvae with full guts were more vulnerable than unfed larvae, the difference increasing with decreasing light intensity. The probability of capture increased with light intensity and body size. There was no evidence of an increasing ability to evade capture as the larvae grew. Against a dark background, larvae with contracted melanophores were more vulnerable than more pigmented larvae; the situation was reversed with a lighter background. The activity of larvae were observed using infra red illumination. Neither the presence of food in the gut nor changing light intensity affected activity levels. The light intensity threshold for feeding was found to differ according to prey type. During encounters with a potential predator the frequency of larvae responding was found to be low. Finally, it was demonstrated that juvenile herring are unaffected by a potential 'alarm substance'.
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Singh-Renton, Susan. "Gadoid feeding: an empirical and theoretical study of factors affecting food consumption and composition in North Sea gadoids, with emphasis on juvenile cod, Gadus morhua (L.) and whiting, Merlangius merlangus (L.)." Thesis, University of Buckingham, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.601444.
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Laboratory experiments were conducted to estimate and compare the gastric evacuation rates, in small cod. Gadus morhua and whiting. Merlangius merlangus (Total length (TL): 20-35 cm), of different types of prey, prey sizes and water temperatures. In addition, the stomach contents of 899 whiting (TL: 18-33 cm), sampled from various parts of the southern and central North Sea , were analysed to determine diet composition, the existence of a diel feeding rhythm and an estimate of the average daily intake of Cranqon vulgaris. Alternative methods for (i) a more direct estimation of relative prey suitability, (ii) treatment of catch-At-age and feeding data in providing estimates of stock size, fishing and predation mortalities, and (iii) smoothing of predation mortality estimates produced within MSVPA, were also investigated.
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Wlasiuk, Jonathan Joseph. "Refining Nature: Standard Oil and the Limits of Efficiency, 1863-1920." Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1323373101.
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Lauerburg, Rebecca [Verfasser], and Axel [Akademischer Betreuer] Temming. "Governing factors for the size-at-age : the influence of sex, food availability, temperature and fishery on the growth performance of North Sea whiting Merlangius merlangus and cod Gadus morhua / Rebecca Lauerburg. Betreuer: Axel Temming." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2016. http://d-nb.info/1106404696/34.
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Adams, Christa. "Bringing "Culture" to Cleveland: East Asian Art, Sympathetic Appropriation, and the Cleveland Museum of Art, 1914-1930." University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1447097382.
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Lloyd, Ryan Allen. "Remote Sensing of Whitings in the Bahamas." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4361.
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Whitings on both the Great Bahama Bank (GBB) and Little Bahama Bank (LBB) were evaluated using data collected from 2000-2010 by the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments onboard the Terra and Aqua satellites. A semi-objective method was developed to classify whiting patches from other look-alike features using the recently developed Floating Algae Index (FAI) algorithm, an empirical cloud masking algorithm, and a gradient analysis from the 250-m resolution MODIS data. A total of 1,500 images with minimal cloud cover was used to calculate long-term and seasonal trends as well as an average daily coverage for both banks. Annual and monthly frequency of occurrences for whitings at every location was also calculated.
Based on the results, the distribution of whitings over the GBB was restricted between 25–30'N and 23–45'N and occurred most frequently on the edge of the bank. Whitings were observed throughout the LBB and at much higher frequencies than in the GBB, especially on the east side from November to February. Results from daily whiting coverage indicate whitings cover nearly twice as much area over the LBB compared to the GBB.
Whitings show a clear seasonal variation with respect to coverage on both banks. Whiting coverage over the LBB has a clear seasonal variation with peak coverage in spring (April) and fall (November) and minimum coverage during summer. Whiting coverage over the GBB peaks in spring (April), but no second peak or seasonal minimum was observed. Sea surface temperature (SST), photosynthetically available radiation (PAR) and wind were compared to the observed long-term and seasonal trends of whiting coverage. Using multi-variable analyses, the influence of SST and PAR on monthly whiting coverage over the GBB from 2000-2010 was found to be statistically significant, though the correlation between the three values was low. The results indicate that these parameters may not directly influence whiting origin and coverage but rather have an effect through influence mechanism, for example through phytoplankton blooms. It is hypothesized that whitings are directly influenced by cyanobacterial phytoplankton, which are dependent on SST and PAR.
Long-term trends in whiting coverage differ between the two banks. In general, whiting coverage appeared to be decreasing from 2000-2010 over the LBB, while the opposite trend was observed over the GBB during the same time period. It is currently unclear what led to these opposite trends due to lack of long-term, in-situ measurements of the water environments in the two banks. However, this is the first study that documents the long-term trends for both banks, from which one may infer that the processes affecting whiting occurrence in the two banks vary greatly and future research is needed to understand the driving forces of whitings in order to improve the current understanding of their contributions in the global carbon cycle.
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Gladwell, Jason Thomas. "Concurrent Whitening and Orthodontic Treatment." VCU Scholars Compass, 2007. http://scholarscompass.vcu.edu/etd/1469.
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The aim was to evaluate whether a whitening system, when used during the final stages of orthodontics, would yield results comparable to whitening alone. Patients were assigned to either the control (n=20) or experimental (n=26) groups. At T1, patients were given a ten day supply of Trèswhite⢠by Opalescence®, instructions on use, and initial shade determination was made and photographs were taken. At T2 and T3, shade determination was accomplished and updated photographs were taken. Whitening of the teeth occurred in both groups on average, but significantly more whitening was experienced in the experimental group (p < 0.004). An average of 87% of teeth whitened during orthodontic treatment compared to 97% of control teeth (p < 0.01) were judged to be uniform in appearance. In conclusion, the data do not contraindicate the concurrent accomplishment of teeth whitening during orthodontic treatment.
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Bustos-Serrano, Hector. "The Carbonate System in Natural Waters." Scholarly Repository, 2010. http://scholarlyrepository.miami.edu/oa_dissertations/493.
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Reliable measurements of the thermodynamics of the carbonate system are needed to better understand the CO2 system in natural waters. New measurements of the carbonic acid pK1* and pK2* in seawater have been made over a wide range of temperatures (1 to 50°C) and salinities. The commonly used CO2 constants of Mehrbach et al., (1973) were limited to salinities (19 to 43) and temperatures (2 to 35°C). They cannot be used to study estuarine or fresh waters. The results of these measured pK1* and pK2* values are in good agreement with those determined using the Miami Pitzer equations (Millero and Pierrot, 1998). The results in this dissertation can be demonstrates the validity of the model that can be used to study the carbonate system in most natural waters. The so called Miami model is presently being used to examine the effect of ocean acidification on natural waters. The boric acid effect on the dissociation constants in seawater and NaCl solutions was tested. The addition of boric acid has little or no effect on pK1* values. However, the values of pK2*, decreases with the addition of small amounts of boric acid to ASW in agreement with the work of Mojica-Prieto and Millero, (2002). The addition of larger concentrations of boric acid cause the values of pK2* to increase. These effects have been attributed to the interactions of boric acid with the carbonate ion (CO32-) in seawater (Mojica-Prieto and Millero, 2002). The addition of boric acid to NaCl solutions in contrast, caused the values of pK1* and pK2* to decrease. This has been attributed to the interactions of borate ions with Mg2+ and Ca2+ in seawater. Further measurements in Na-Mg-Cl and Na-Ca-Cl solutions are needed to prove that this is the case. The boric acid effect on the carbonate constants indicate that an increase in boric acid has no affect on pK1*, but does change the values of pK2*. At low concentrations of boric acid, pK*2 decreases, and at higher concentrations it increases. These results indicate that boric acid has some ionic interactions with the carbonate ion. Similar studies in NaCl indicate that both pK1* and pK2* decrease when boric acid is added. The differences between seawater and NaCl may be related to the interactions of Mg2+ and Ca2+ with borate anions. Further studies of NaCl with additions of MgCl2 and CaCl2 are needed to examine the effects in detail. Preliminary studies on the effect of DOC on the carbonate constants are not definitive. The change of the DOC concentration from 50 to 100 µmol kg-1 has little effect on the values of pK1* and pK2*. Dilutions of seawater with artificial seawater are complicated by changes in the concentration of boric acid. Earlier studies indicated that DOC may cause the 8 mu-mol kg-1 increase in total alkalinity of seawater needed to balance the thermodynamics of the system (Millero et al., 2002). This may be partially due to the new values for the B/Cl ratio in seawater found by Lee et al., (2010) that increases the TA by ~ 6 µmol kg-1. Further studies are needed to examine the effect of humic compounds in estuarine waters on the carbonate system. Measurements of pH or pCO2 along with TA and TCO2 can be used to separate the effect of organic ligands on TA. If DOC measurements are also made, one can relate the effect to organic ligands that can accept a proton. The cruises in the Little Bahama Banks show for the first time the active precipitation of CaCO3 (Bustos-Serrano et al., 2009). This causes measured decreases of TA, TCO2 and pH and increases in pCO2 in the whitings. This is in contrast to earlier studies on the Grand Bahama Banks where no active precipitation of CaCO3 was every found (Morse et al., 2003; Millero et al., 2005). The differences appear to be due to the movement of fresh saturated seawater from the Gulf Stream into the LBB. The Gulf Stream water enters the GBB in the winter, and the precipitation occurs on the suspended sediment over the year. Observations are needed on the Grand Bahama Banks in the winter and throughout the year to prove that this is the case.
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Reeve, Glen M. D. "Sedimentation And Hydrodynamics of Whitianga Estuary." The University of Waikato, 2008. http://hdl.handle.net/10289/2344.
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Whitianga Estuary is a bayhead barrier type estuary located on the east of the Coromandel Peninsula, North Island, New Zealand. The catchment has undergone many land-use changes since pre-European settlement. In some areas of the catchment land-use has changed from native forest to grasslands to forestry and back to pasture. These changes in catchment land-use all contribute to increased sedimentation into the estuary. Development of the estuary itself has also occurred in recent times. Much growth has been focussed around the estuary due to Whitianga town-ship having a large boating community, and includes a 170 berth marina and wharf situated at the tidal inlet entrance to the estuary. These, and the extensive canal development engineering works can have substantial impacts on the sedimentation regime, and may modify tidal circulation, flushing, and sediment deposition within the estuary. The principle aim of this research is to assess hydrodynamics and sedimentation of the estuary for future management and development purposes, and also to model different scenarios in order to determine the most cost effective, and least obtrusive design for a proposed boat-ramp and approach channel near the marina. To determine sedimentation rates, sediment cores from four locations were collected to depths of 1 m. Coring locations were chosen based on preliminary model run results, selecting areas that appeared to be long-term sediment sinks of a stable nature. Cores were divided into 10 mm sections and prepared for 210Pb dating and heavy metal analysis, to make an assessment of the vertical sedimentation rates. Recent sedimentation rates were found to be as high as 9 mm/yr post-1950s and past sedimentation rates as high as 30 mm/yr pre-1950s. The use of heavy metal analysis for dating proved difficult as the background levels of the conservative elements used to normalise results varied, making the geochemical analysis approach inappropriate. As bathymetry is one of the most important aspects of modelling, a large amount of surveying was undertaken for this study. LiDAR, singlebeam data, and recent rectified aerial photographs were interpreted for the creation of a bathymetric grid file to be used for hydrodynamic modelling of the estuary. The 3DD numerical model was used to determine tidal flows and current velocities. From this initial hydrodynamic model a particle-tracking model was created to determine sediment transport pathways within the estuary. From the initial 20 m model it was then possible to create a number of nested model grids for the purpose of determining the best practice scenario for the creation of a proposed boat ramp and associated approach channel near the harbour entrance. Hydrodynamic results suggest that residual circulation in Whitianga Estuary is nearly in balance, with a low ebb tidal domination present. Particle tracking results suggest that sediment entrained and carried into and within the estuary will accumulate on the intertidal flats. Sediment transport modelling indicates that the impact of a proposed boat-ramp will result in sedimentation of the dredged approach channel due to reductions in residual and tidal velocities.
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Santos, Tales dos. "Emergindo das trevas: análise do discurso metal sinfônico em Whitin Temptation." Universidade Presbiteriana Mackenzie, 2017. http://tede.mackenzie.br/jspui/handle/tede/3273.
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Previous issue date: 2017-05-19<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>Instituto Presbiteriano Mackenzie<br>The present dissertation is based on the area of concentration of discursive and textual studies and inserted in the line of research of Procedures of Constitution of the Meanings of the Speech and of the Text of the Post-Graduate Program in Letters of Mackenzie Presbyterian University (UPM). The research aims to investigate which are the discursive elements that compose the symphonic metal and to analyze the path that the heavy metal style goes through when moving its interdiscourses. During the heavy metal trajectory, the construction of the association of songs and bands with violent, anarchic and satanic behaviors was constant and subjected the style to be in the darker side of the musical scene. However, fans were increasingly producing and releasing heavy lyrics so they could achieve the commercial and financial success of the genre. In this way, we work with the hypothesis that in the late 1990s a movement within the heavy metal called the symphonic metal arises with an unprecedented proposal in its theme: to re-signify the relation of life and death through the exit of the discourse of hesitation to The discourse of resistance. We work with the ideas developed by Dominique Maingueneau (2008a, 2008b, 2010, 2013, 2014, 2015) to understand the relationship between life and death. We investigated the relationships between interdiscursive and discursive formation, the enunciation scenes, and the overdubbed statements in the lyrics of Our solemn hour, Iron and Covered by Roses from their respective studio albums - The Heart of Everything (2007), The Unforgiving (2011) and Hydra (2014) of the metal band Within Temptation. We also consider only two elements of music that are constitutive for the understanding of discourses: the effects of sense of the relation between sharp and guttural and the orchestral effect. The results of the research point out that for the discourse of hesitation to excel, it was necessary to value the theme of death, while the discourse of resistance was highlighted due to the valorization of the theme of life.<br>A presente dissertação está alicerçada na área de concentração dos estudos discursivos e textuais e inserida na linha de pesquisa de Procedimentos de Constituição dos Sentidos do Discurso e do Texto do programa de Pós-graduação em Letras da Universidade Presbiteriana Mackenzie (UPM). A pesquisa tem por objetivo investigar quais são os elementos discursivos que compõem o metal sinfônico e analisar o percurso que o estilo pertencente ao metal pesado percorre ao movimentar seus interdiscursos. Durante a trajetória do Heavy Metal, a construção da associação de músicas e de bandas com comportamentos violentos, anárquicos e satânicos era constante e sujeitava o estilo a ficar no lado mais sombrio do cenário musical. No entanto, os fãs produziam e divulgavam cada vez mais letras de músicas pesadas permitindo, dessa forma, alcançar o sucesso comercial e financeiro do gênero. Trabalhamos, assim, com a hipótese de que no final dos anos 1990, um movimento dentro do metal pesado chamado metal sinfônico surge com uma proposta inédita em sua temática: ressignificar a relação de vida e de morte por meio da saída do discurso de hesitação para o discurso de resistência. Trabalhamos com as ideias desenvolvidas por Dominique Maingueneau (2008a; 2008b; 2010; 2013, 2014, 2015) para compreender a relação entre vida e morte. Investigamos as relações entre interdiscurso e formação discursiva, as cenas de enunciação e os enunciados sobreasseverados presentes nas letras das músicas Our solemn hour, Iron e Covered by roses dos respectivos álbuns de estúdio – The heart of everything (2007), The Unforgiving (2011) e Hydra (2014) da banda de metal sinfônico Within Temptation. Consideramos ainda somente dois elementos da música que são constitutivos para a compreensão dos discursos: os efeitos de sentido da relação entre agudo e gutural e o efeito orquestral. Os resultados da pesquisa apontam que para o discurso de hesitação se sobressair foi necessário valorizar a temática da morte, enquanto o discurso da resistência se destacou devido à valorização da temática da vida.
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Aman, Zaeem. "Efficiency of Fluorescent Whitening Agents in Pigment Coatings." Thesis, Karlstads universitet, Fakulteten för teknik- och naturvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-14976.
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The objective of this work was to study the addition of fluorescent whitening agents (FWAs) for efficient use on pigment coating of paper substrates with low grammage and the goal was to achieve high optical response by using low amount of FWAs. A commercial light-weight coated (LWC) paper grade was provided by Stora Enso Corbehem Mill and isotropic laboratory sheets were produced at Stora Enso Research Centre using PFI sheet former. Optical properties such as brightness, whiteness and L, a* and b* colour space values were evaluated using Minolta spectrophotometer with D65 illuminant for both types of substrate using different types and amounts of FWA while the effect of the addition of dye was evaluated in both isotropic sheets and as well as in the coating. The results showed that brightness and whiteness of double-coated paper increased by increasing the amount of fluorescent whitening agent in the coating layer. Also, higher brightness and whiteness was achieved by introducing a higher amount of fluorescent whitening agent in the top coating rather than in a pre-coating. The addition of a shading colorant in the paper substrate had a positive influence not only on the brightness but also on the whiteness of coated paper.<br>Syftet med denna studie var att studera tillsatsen av fluorescerande vitmedel (FWA) för att effektivisera användningen i pigmentbestrykning av papper med låg ytvikt. Målet var att nå en hög optisk respons men ändå använda en låg mängd FWA. Ett kommersiellt LWC-papper erhölls från Stora Enso, Corbehems pappersbruk, och isotropa laboratorieark tillverkades med PFI-arkformerare på Stora Enso Research Centre. Optiska egenskaper, såsom ljushet, vithet och färgrymd (L, a* och b* värden), hos samtliga prover med varierande mängd och typ av FWA uppmättes med hjälp av en Minolta spektrofotometer med D65 ljuskälla. Effekten av färgnyanstillsats utvärderades både hos handgjorda ark och hos bestrykningslager. Resultaten visade att både ljushet och vithet hos dubbelbestrukna ark ökade med ökad mängd FWA i bestrykningslagren. Högre ljushet och vithet nåddes också när FWA placerades i toppbestrykningen. Tillsats av nyanseringsfärg i papperssubstratet ökade både ljushet och vithet hos de bestrukna arken.
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Chen, Ye. "Measurement of white colour containing fluorescent whitening agent." Thesis, University of Leeds, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.713487.
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Various experiments have been conducted to investigate the influence of fluorescent whitening agent (FWA) on aspects of colour evaluation. Large amount of samples were prepared by direct dyeing with various concentration of colorant dyes as well as FWA. These dyed samples, together with high-FWA-content samples provided by third party, were used as stimuli in instrumental measurement by spectrophotometer and tele-spectroradiometer as well as in psychophysical experiment. The influence of FWA on instrumental illumination variation, calibration methods' performance, calibration standards' performance are studied. It was found that there is no significant relationship between the material of measured target and calibration standard. It is also found that spectrophotometers agrees well if the UV content in illumination is properly calibrated. A practical design of viewing cabinet with improved quality in UV range was proposed. The additional calibrated UV lamp significantly improved the fluorescent daylight lamps performance in term of metamerism index. Such improvement in UV enabled common viewing cabinets be upgraded to cater the need of visual assessment involving FWA. Three pairs of metameric samples were developed which matched under illumination with certain UV component while mismatched under illumination with other UV conditions. These metameric pairs were developed as UV Visual Aid which could be used as practical checker to visualize the UV quality in light conditions. Psychophysical experiment with category-judgment method was conducted to investigate the preferred white of human. Mean-category-value and ellipsoid fitting were used to find the resulting preferred white colour. There were significant amount of samples which were not within the Tint limit of CIE Whiteness index but were categorized by observers as acceptable white. This indicated the possible need of expanding the Tint limit of CIE Whiteness. Psychophysical experiment with magnitude estimation method was conducted to evaluate the prediction of visual whiteness by various whiteness formulae. CIE Whiteness index had the best agreement between instrumental prediction and visual perception, outperforming Uchida and C/V Whiteness.
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Koirala, Kishor. "Anticipatory Electromyogram-Torque Estimation and Effect of Whitening Bandwidth." Digital WPI, 2013. https://digitalcommons.wpi.edu/etd-theses/247.
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The electromyogram has numerous applications in engineering and science. One specific application is to model a system for the torque generated by the elbow joint. This application has been long studied and applied in controller designs for artificial prosthetics limbs. Previous research had shown that nonlinear and multiple channel whitened EMG signal models gave the best EMG to torque estimates compared to linear un-whitened models. This thesis describes the methodologies for predicting the torque into the future up to 1 second. Four specific types of finite impulse response models (linear and nonlinear, single channel un-whitened and multi-channel whitened) are compared based on the EMG-based predicted torque and the actual torque. The errors were measured as the difference between actual and predicted torque. It was observed that the error was mostly constant at the minimum error value between 0 and 80 ms for all four models, with the lowest error being 5.48 % maximum voluntary contraction (MVC) flexion. Further comparison was performed between different lower order models and a Butterworth second order model for predicting torque ahead in time. Such models are common in the literature. This thesis separately investigates the effect of band limiting the whitened EMG signal and using the advanced EMG processors for estimating the torque. Whitened EMG data were passed through a low pass filter with selectable cutoff frequency from 2048 Hz down to 20 Hz to limit the whitened band width. It was observed that the error was not significantly different for bandwidths down to approximately 400-600 Hz, grew gradually as the band width further decreased to 200 Hz, beyond which the error increased sharply. It can be inferred that for this particular study consisting of lower contraction levels, there is no significant power usable for whitening in the EMG signal at higher frequencies, providing an opportunity for lower sampling rate, effective noise suppression, better signal to noise ratio and implementation of low cost electrodes. This research work lead to two conference paper publications at the 2013 IEEE 39th Annual Northeast Bioengineering Conference. Two journal papers are in the writing and preparation stage which will be submitted after their completion.
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Srinivas, Umamahesh Bose N. K. "Thermal image superresolution and higher order whitening of images." [University Park, Pa.] : Pennsylvania State University, 2009. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-3979/index.html.
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Wong, Ho-hang Anthony. "A randomized controlled trial of home tooth-whitening products." Click to view the E-thesis via HKUTO, 2004. http://sunzi.lib.hku.hk/hkuto/record/B3195439X.
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Qusti, Najlaa Yusef Mohammed. "Investigating the clinical and laboratory aspects of tooth whitening." Thesis, University of Leeds, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612614.
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Although bleaching is considered a conservative technique, controversy surrounds whether bleaching demineralises or modifies tooth surfaces. Little is known about how bleaching may predispose enamel to subsequent acid challenges or how it affects the adsorption of protective salivary pellicles. Aim: To investigate the effects of bleaching on: susceptibility of hydroxyapatite to subsequent acid attack; on adsorption of salivary proteins and their protective properties and to carry out an in situ study to investigate the impact of a commercial bleaching product on mineral density of human enamel. Methods: Hydroxyapatite powder bleached in vitro was used to examine the effect of bleaching on: acid solubility; salivary protein adsorption and the protective properties of adsorbed salivary proteins using SDS-PAGE and for protein identification using mass spectrometry. An in situ study, employing extra-oral bleaching, examined the effect of bleaching ' on enamel mineral density as measured by X-ray NanoCT scanning technique. Results: The results indicated that bleaching had no effect on hydroxyapatite acid susceptibility. However, bleaching did affect the adsorption of salivary proteins such as a-salivary amylase. A novel finding was that the precise effect observed was donor specific i.e. salivary protein heterogeneity between individuals dictated how bleaching effected the nature of the adsorbed salivary pellicle. Bleaching appeared to significantly increase the ability of the salivary pellicle to protect hydroxyapatite from acid attack. Increasing the pH of the bleaching agent enhanced subsequent adsorption of the model protein bovine serum albumin. The in situ study indicated that the bleaching regime used here had no significant effect on the inner enamel but Significantly increased mean mineral density at the enamel surface by 6.8%. It is suggested that peroxide incorporates in the hydroxyapatite lattice and modifies mineral properties. Conclusions: Overall, data indicates that the specific bleaching regimes employed here do not have a detrimental effect on mineral density and may actually increase mineral density.
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Wong, Ho-hang Anthony, and 黃浩行. "A randomized controlled trial of home tooth-whitening products." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B3195439X.
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Jauhar, Ahmad Shujauddin. "A CMA-FRESH Whitening Filter for Blind Interference Rejection." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/85389.
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The advent of spectrum sharing has increased the need for robust interference rejection methods. The Citizens Broadband Radio Service (CBRS) band is soon to be occupied by LTE waveforms and License Assisted Access (LAA) will have LTE signals coexisting with other signals in the 5 GHz band. In anticipation of this need, we present a method for interference rejection of cyclostationary signals, which can also help avoid interference through better detection of low power co-channel signals. The method proposed in this thesis consists of a frequency-shift (FRESH) filter which acts as a whitening filter, canceling the interference by exploiting its cyclostationarity. It learns the cyclostationary characteristics of the interferer blindly, through a property restoration algorithm which aims to drive the spectrum to white noise. The property restoration algorithm, inspired by the constant modulus algorithm (CMA), is applied to each frequency bin to determine the optimal coefficients for the proposed CMA FRESH whitening filter (CFW). The performance of the CFW in interference rejection is compared to a time-invariant version, and proposed use cases are analyzed. The use cases consist of the rejection of a high powered, wider bandwidth interferer which is masking the signal-of-interest (SOI). The interferer is rejected blindly, with no knowledge of its characteristics. We analyzed signal detection performance in the case that the SOI is another user with much lower power, for multiple types of SOIs ranging from BPSK to OFDM. We also deal with the case that the SOI is to be received and demodulated; we recover it and compare resulting bit error rates to state of the art FRESH filters. The results show significantly better signal detection and recovery.<br>Master of Science<br>Wireless communication is complicated by the fact that multiple radios may be attempting to transmit at the same frequency, time and location concurrently. This scenario may be a due to malicious intent by certain radios (jamming), or mere confusion due to a lack of knowledge that another radio is transmitting in the same channel. The latter scenario is more common due to congested wireless spectrum, as the number of devices increases exponentially. In either case, interference results. We present a novel interference rejection method in this work, one that is blind to the properties of the interferer and adapts to cancel it. It follows the philosophy of property restoration as extolled by the constant modulus algorithm (CMA) and is a frequency shift (FRESH) filter, hence the name. The process of restoring the wireless spectrum to white noise is what makes it a whitening filter, and is also how it adapts to cancel interference. Such a filter has myriad possible uses, and we examine the use case of rejecting interference to detect or recover the signal-of-interest (SOI) that we are attempting to receive. We present performance results in both cases and compare with conventional time-invariant filters and state of the art FRESH filters.
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Schilling, Alexandra. "Reinigungswirkung und Abrasionsverhalten von Whitening-Zahnpasten : eine In-vitro-Studie /." Freiburg i. Br, 2009. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000256381.
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Liu, Jian. "Encapsulation of fluorescent whitening agents by cyclodextrins and their application." Thesis, University of Kent, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358719.
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Dhir, Ritu. "CAUSES OF WHITENING OF IVY GERANIUMS (Pelargonium peltatum)." Diss., Mississippi State : Mississippi State University, 2008. http://library.msstate.edu/etd/show.asp?etd=etd-04012008-145127.
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Campbell, J. "The fate of fluorescent whitening agents in the aquatic environment." Thesis, University of South Wales, 1990. https://pure.southwales.ac.uk/en/studentthesis/the-fate-of-fluorescent-whitening-agents-in-the-aquatic-environment(4566785a-529e-4e59-873c-757b7aa19a23).html.
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The commercial use of fluorescent whitening agents (FWA' s) in products such as soaps and detergents has resulted in the presence of these compounds in domestic waste waters. A model compound (A) (a possible initial degradation product of a stilbene-s-triazine type FWA) was synthesised and biodegradation studies carried out on this compound in filtered activated sludge solution. During the test period (approximately 6 months) no degradation products were observed. Prior to undertaking biodegradation studies on a purified commercial stilbene-s-triazine FWA, Blankophor REU-P, a method was sought to determine its concentration in aqueous solution. Using ultraviolet absorbance measurements the concentration of the Blankophor could be determined in distilled water. However, this method was unsuitable when the Blankophor was dissolved in filtered activated sludge solution. Attempts to extract the Blankophor from filtered activated sludge solution using solvent extraction and ion-exchange resins were unsuccessful. Using computer modelling (SIMCA), combined with ultraviolet absorbance measurements, it was possible to determine the concentration of the Blankophor in filtered activated sludge solution. Biodegradation studies were undertaken with the Blankophor using this method to monitor the Blankophor concentration. During the test period (six days) the Blankophor concentration fell from 1Oppm to approximately 5. 5ppm. It was possible to deduce that the Blankophor was not being absorbed onto the solid material of the activated sludge and that it had been metabolised and/or isomerised. Two ion-pairing agents, tetraphenyl arsoniurn chloride and oly[oxyethylene(dimethylimino)-ethylene(diethylimino)-ethylene] were examined to try to separate the Blankophor and the metabolites and/or isomers from the filtered activated sludge solution but no successful separation was achieved. Thin layer chromatography was examined briefly but again with no success. Photolysis experiments were undertaken with the Blankophor in distilled water. The concentration of the Blankophor fell from 1Oppm to approximately 7. 5ppm and its ultraviolet spectrum changed shape. This, coupled with the fact that the control spectra remained unaltered, indicated that the Blankophor had undergone photolytic conversion to metabolites and/or isomers. Although it is clear that FWA' s are fairly stable compounds which are slow to bio- and photo-degrade and that their toxicity to man, both directly and by bio-accumulationis is minimal little is still known about the toxicity of possible degradation products.
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Wang, He. "Advanced Electromyogram Signal Processing with an Emphasis on Simplified, Near-Optimal Whitening." Digital WPI, 2019. https://digitalcommons.wpi.edu/etd-theses/1338.
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Estimates of the time-varying standard deviation of the surface EMG signal (EMGσ) are extensively used in the field of EMG-torque estimation. The use of a whitening filter can substantially improve the accuracy of EMGσ estimation by removing the signal correlation and increasing the statistical bandwidth. However, a subject-specific whitening filter which is calibrated to each subject, is quite complex and inconvenient. To solve this problem, we first calibrated a 60th-order “Universal” FIR whitening filter by using the ensemble mean of the inverse of the square root of the power spectral density (PSD) of the noise-free EMG signal. Pre-existing data from elbow contraction of 64 subjects, providing 512 recording trials were used. The test error on an EMG-torque task based on the “Universal” FIR whitening filter had a mean error of 4.80% maximum voluntary contraction (MVC) with a standard deviation of 2.03% MVC. Meanwhile the subject-specific whitening filter had performance of 4.84±1.98% MVC (both have a whitening band limit at 600 Hz). These two methods had no statistical difference. Furthermore, a 2nd-order IIR whitening filter was designed based on the magnitude response of the “Universal” FIR whitening filter, via the differential evolution algorithm. The performance of this IIR whitening filter was very similar to the FIR filter, with a performance of 4.81±2.12% MVC. A statistical test showed that these two methods had no significant difference either. Additionally, a complete theory of EMG in additive measured noise contraction modeling is described. Results show that subtracting the variance of whitened noise by computing the root difference of the square (RDS) is the correct way to remove noise from the EMG signal.
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Steeghs, Lauren. "Morphodynamics of the Whitianga Tidal Inlet and Buffalo Bay, New Zealand." The University of Waikato, 2007. http://hdl.handle.net/10289/2447.
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The primary aim of this study was to investigate the sedimentation processes within Buffalo Bay, particularly within and adjacent to the Whitianga tidal inlet, in order to ascertain reasons for the shoaling at both the inlet, and the identified shallow zone around Pandora Rock. Comparison of historic bathymetries suggests the ebb delta and ebb discharge channel of the Whitianga tidal inlet are rapidly accreting and the ebb tidal discharge channel is gradually migrating northeast towards Whakapenui Point. Accretion rates of up to 25 cm y-1 were calculated in the ebb delta and inlet discharge channel area between 1979 and 1995 and aerial photo comparisons suggest the ebb delta area had increased by 400 % between 1990 and 2002. Results of the hydrodynamic and sediment transport modelling suggest the rapid accretion in the ebb delta vicinity is likely to be caused by a combination of catchment estuary inputs, which are deposited on the ebb tide as the ebb flow decelerates over the ebb delta, and inputs that have been moved south along Buffalo Beach by flood currents and an eddy that forms landward of the ebb tidal discharge. Residual tidal velocities further suggest a deposition zone in the ebb delta vicinity resulting from opposing currents and the deceleration of currents. Hydrodynamic modelling results indicate the isolated shallow zone around Pandora rock appears to be caused by a transient eddy in the southern section of Buffalo Bay. The eddy is formed by the ebb tidal discharge from the inlet. Accretion probably occurs in the centre of the eddy which moves north as the ebb tide progresses. Results obtained from a current meter and sediment trap deployed in northern Buffalo Bay suggest suspended sediment transport is minimal in northern Buffalo Bay, only occurring with large wave activity. Results of the hydrodynamic and sediment transport modelling further demonstrate that this area experiences low flow velocities, and has little interaction with the rest of Buffalo Bay. The minimal sediment input to this area, combined with the occasional erosion of the seafloor, primarily by wave activity, is thought to have resulted in long term erosion of northwestern Buffalo Bay between 1938 and 1979. Although the beach and nearshore is eroding, it is likely the addition of sediment would act to stabilise this section of eroding beach. Renourishment material could be provided by the ebb delta, the southern tip of Buffalo Bay or the isolated sandbar northeast of the inlet entrance.
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Lütkemeyer, Christian. "Konzeption eines Fractionally-Spaced Entzerrers mit quantisierter Rückkopplung und Noise-Whitening /." Düsseldorf : VDI-Verl, 1999. http://www.gbv.de/dms/bs/toc/270561633.pdf.
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Pipatsattayanuwong, Siriporn. "Alternative products from Pacific whiting : fresh surimi and texturized mince." Thesis, 1995. http://hdl.handle.net/1957/27380.
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The major portion of Pacific whiting (PW) is commercialized in the form of frozen
surimi. Alternative products for PW were investigated focusing on fresh surimi and
texturized meat from PW mince. Fresh surimi is made without additives and kept
refrigerated instead of frozen. Texturized meat is a meat-like product made from PW
mince through freeze-texturization.
Fresh surimi was stored at 5°C and analyzed for its total aerobic plate count
(APC), shear stress, shear strain, and color during 7 days storage. Frozen surimi from PW
was prepared with 0, 3, 6, and 9% cryoprotectants and was compared with fresh surimi
for its gel forming ability. Fresh surimi had a shelf life of 5 days and the gel forming ability
remained unchanged throughout storage time. Shear strain of fresh surimi was not different from frozen surimi with 9% cryoprotectants but shear stress was almost 3 times
higher than the frozen one.
Texturized meat from PW mince was prepared from unwashed or 1-washed mince
kept frozen for 6-8 mo with or without the addition of 6% cryoprotectants. The minces
were comminuted into a protein slurry, formed into patties, and frozen at -7, -18, and
-50°C. The evaluations of ice formation (by microscopic study), hardness, cook loss,
color, and water holding capacity were carried out during 20 days storage. The results
showed that texturized meat with parallel layers was made from 1-washed PW mince.
Unwashed PW mince created a sponge-like texture and had rapid quality deterioration,
thus it is not recommended for this product. Cryoprotectants did not significantly affect
the texture formation of the product and are not required to store mince as raw material
for the texturized meat. The optimum freeze-texturized temperature for this product was
-18°C or lower because it minimized quality changes during storage depending on the
desirable texture. The lower the temperature (higher freezing rate), the finer the layers
created.<br>Graduation date: 1996
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Yongsawatdigul, Jirawat. "Textural and electrical properties of Pacific whiting surimi under ohmic heating." Thesis, 1996. http://hdl.handle.net/1957/27046.
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Feasibility of ohmic heating to overcome gel-weakening in Pacific whiting surimi
was investigated. An ohmic heating apparatus was developed using two rhodium-coated
stainless steel electrodes inside a polyvinyl chloride (PVC) tube, a variable transformer,
and voltage and current transducers. Rapid heating associated with the ohmic process
quickly inactivated endogenous proteinase(s), resulting in significantly high shear stress
and shear strain of surimi gels (78% moisture content, 2% NaCl). Degradation of myosin
heavy chain (MHC) and actin examined by SDS-PAGE were significantly reduced and
continuous gel structure were shown by scanning electron microscopy. Whiting surimi
heated in a 90°C water bath for 15 min exhibited poor gel quality and disordered
microstructure due to proteolysis of MHC.
Electrical conductivity, a critical parameter influencing rate of heat generation
during ohmic heating, was elucidated. Electrical conductivities of whiting surimi pastes
with four moisture contents (75, 78, 81, and 84% wet basis) and added NaCl (1, 2, 3, and 4%) were measured from 10 to 90°C using ohmic heating at voltage gradient of 3.3, 6.7,
and 13.3 V/cm. Electrical conductivity significantly increased with temperature and salt
content and slightly increased with moisture content. The effect of the voltage gradient
was evident at combinations of high moisture (81, 84%) and NaCl content (3, 4%), due
to electrochemical reactions at the electrodes. The empirical model of electrical
conductivity as a function of temperature and compositional characteristics predicted
values with an error range of 0-15.6%.
Finally, kinetic models of textural degradation of whiting surimi were developed
using two different approaches: isothermal and nonisothermal procedure over a range of
temperature (40-85°C) and time (0.5-35 min). The effect of thermal lag was accounted
for using the models derived from the Arrhenius equation. Textural degradation obtained
from both methods followed first order kinetic. Degradation of MHC derived from
nonisothermal procedure was best described by apparent reaction order of 1.4.
Degradation rate of gel texture and MHC increased with temperature and reached the
highest rate at 55 and 57°C, respectively. Then they decreased to minimum rate at 70
and 75°C, respectively. The kinetic model for the loss of MHC satisfactorily estimated
MHC content of the controls with an averaged error of 10.8%. Relationship between
degradation of MHC and gel texture are discussed.<br>Graduation date: 1996
38
Wendel, Ari P. "Recovery and utilization of Pacific whiting frame meat for surimi production." Thesis, 1999. http://hdl.handle.net/1957/33265.
Full textAbstract:
In surimi manufacturing, less than 25% of the total weight of the fish is utilized. This research focused on meat recovery from fish frames, the residual portion of the fish after filleting headed and gutted fish. A new technology, the water jet deboning (WJD) system, was tested. The WJD system uses oscillating high pressure water jet nozzles to recover edible flesh from the frames without breaking the kidney located under the backbone. To evaluate the function of added salt on dewatering and process recovery, the WJD was operated without NaCl (WJD1) and with 0.2% NaCl added to the discharge slurry (WJD2). In conventional mechanical deboning process (MD), which was the other deboning system applied in the study, no salt was used. The recovered frame meat was further processed to surimi and then stored at -18��C. Meat recovery and surimi processing yields were compared between the three meat recovery processes.
Functional properties of gels (texture and color) were evaluated after 1 and 6 mo frozen
storage and compared to commercially manufactured surimi, which served as a control.
As a result of manual trimming, the maximally recoverable meat from the frames was 42.8% of frame weight. MD showed the highest mince yield (mince prior to cryoprotectant addition), 24% of frame weight, while the two WJD methods resulted in only 5% yield. Color and shear strain for gels from WJD1, MD surimi and mixtures of those and control (10-20% frame mince surimi/80-90% control), were comparable to control. Gels from WJD2 showed significantly lower lightness (L*) but did not differ otherwise. Shear stress values of all frame meat surimi gels and the gels from mixtures of those and the control were significantly lower than the control. This low shear stress is probably due to a difference in processing equipment and processing conditions between the lab scale and the commercial scale.
Due to the promising processing yield for the MD system an additional study was performed where effects of kidney and kidney blood contamination in the frame mince were investigated. Pacific whiting frames were mechanically deboned with/without kidney and the frame mince further processed into surimi. Functional properties of gels (texture and color) were evaluated after 1 and 6 mo frozen storage and compared to commercially manufactured surimi, which served as a control. At 1, 2, 4, and 6 mo, salt extractable proteins (SEP) concentration, dimethylamine (DMA) formation and pH were measured to monitor protein denaturation. Removing the kidney and washing the frames prior to MD resulted in higher gel strength after 1 and 6 mo frozen storage.<br>Graduation date: 2000
39
Enr��quez, Andrade Roberto R. "Multiobjective model of the Pacific whiting fishery in the United States." Thesis, 1992. http://hdl.handle.net/1957/35741.
Full textAbstract:
Pacific whiting (Merluccius productus) is commercially
and ecologically one of the most important fishery resources
in the Pacific coast of the United States. The fishery
is currently going through a period of rapid and profound
transformation that could cause a substantial redistribution
of benefits among domestic users. Benefits from the
Pacific whiting fishery consist of conflicting biological,
social, economic and regional objectives. A major management
issue is the problem of resource allocation between
the domestic offshore and shore-based fleets.
Economic analysis of fishery policy based on the
single objective of maximizing present value of net revenues
(PVNR) fails to realistically confront the Pacific
whiting fishery management problem. This work proposes the
use of the less restrictive concept of Pareto optimality as
a criterion for efficiency in the fishery.
The main objective of this dissertation is to develop
a multiobjective bioeconomic policy model of the Pacific
whiting fishery in the United States. The purpose of the
model is to analyze the implications (trade-offs) of resource
allocation alternatives on the level of three policy
objectives PVNR, production, and female spawning biomass.
Pareto optimal solutions for the three policy objectives
were generated under various specifications of the model by
means of generating techniques. Three policy instruments
were considered: harvest quotas, fleet/processing capacity
limits, and allocation between the shore-based and offshore
fisheries. Results were presented in the form of trade-off
curves.
The analysis suggests that policy objectives in the
case of Pacific whiting are non-complementary. Instead of
a unique "optimal" policy solution the Pacific whiting
fishery policy problem possesses an infinite number of
[Pareto] "optimal" policy solutions. The principal characteristic
of Pareto optimal solutions is that in moving from
one to another, the objectives must be traded-off among
each other. In spite of the uncertainties regarding the
dynamics of the Pacific whiting fishery, the preliminary
nature of the data and the simplistic specification of the
model, the analysis in this work demonstrates the potential
benefits of vector optimization for fishery policy development
and analysis.<br>Graduation date: 1993
40
Benjakul, Soottawat. "Utilization of wastes from Pacific whiting surimi manufacturing : proteinases and protein hydrolysate." Thesis, 1997. http://hdl.handle.net/1957/27453.
Full textAbstract:
Both liquid and solid wastes from Pacific whiting surimi manufacturing were
characterized and value-added products were recovered. A proteinase in surimi wash
water (SWW) was determined to be cathepsin L with Mr 54,200 on SDS-substrate gel.
Heat treatment and acidification shifted the activity zone to M [subscript r] 39,500. No evidence of
calpain, cathepsin B or H activity was found. Cathepsin L from SWW was recovered
by ohmic heating (55°C for 3 min), ultrafiltration, and freeze-drying with overall yield
of 0.83 g protein/L SWW and 78% recovery of activity. A 5.9 purification fold was
achieved by these processes. The recovered enzyme had an optimum activity at pH 4.0
and showed preferable hydrolytic activity towards casein, acid-denatured hemoglobin and
myofibrils. β-Mercaptoethanol, dithiothreitol and urea enhanced the enzyme
activity. The recovered proteinase showed 18.5% residual activity after
7 wk storage at 4°C.
Proteolytic activity in solid waste and digestive organs from Pacific whiting was
investigated. Pepsin-like proteinase predominated in solid waste, while trypsin-like
proteinase was predominant in viscera. Carboxypeptidase b was found in both viscera
and solid waste.
Protein hydrolysate was produced from Pacific whiting solid waste (PWSW) using
commercial proteinase, Alcalase, under optimum hydrolysis conditions. Enzyme
concentration, reaction time and waste/buffer ratio affected the hydrolysis and nitrogen
recovery (NR). Correlation between the degree of hydrolysis (DH) and NR was high
(R₂=0.978). Freeze-dried hydrolysate contained 79.97% protein and showed similar
amino acid composition to PWSW and Pacific whiting muscle but tryptophan was
reduced. With different DH (20, 30, 40, 50, 60%), surface hydrophobicity, total and
surface sulfhydryl content decreased as the DH increased. The hydrolysate showed a
high solubility over a wide pH range. Fat adsorption and fat binding capacity were
reduced, while foam expansion was enhanced with an increased DH. Hydrolysate with
DH of 30% showed highest emulsifying activity. Low emulsion stability and high foam
stability were obtained in all hydrolysates tested. Hydrolysate showed antioxidant
activity, but no obvious differences in activity were found with varying DH and
hydrolysate concentrations.<br>Graduation date: 1997
41
Lopetcharat, Kannapon. "Fish sauce : the alternative solution for Pacific whiting and its by-products." Thesis, 1999. http://hdl.handle.net/1957/26555.
Full textAbstract:
Pacific whiting and its by-products were good raw materials for high quality
fish sauce production. Heat stable and salt activated enzymes were responsible for
autolytic activity in Pacific whiting and by-products. According to temperature
profiles of raw materials at various salt concentrations, two fermentation
temperatures, 35°C and 50°C, were selected and compared at 25% salt under static
atmospheric condition. Higher yields and faster production rate were obtained
from samples incubated at 50°C. Therefore, the apparent optimum condition for
fish sauce fermentation using Pacific whiting and its by-products was at 50°C with
25% salt under static atmospheric condition. All physicochemical characteristics,
except color and browning color, reached the level of commercial fish sauce within
20 days. Nitrogen contents in all samples reached the level of commercial fish
sauce (16.3 g-N/mL) within 112 days. Predominant microorganisms found during
fermentation were Staphylococcus, Bacillus and Micrococcus. Alpha-amino acid content appeared to be identified as a good parameter to estimate total nitrogen
content during fermentation (adjusted R²=0.84). Soluble solid was a good index
for protein degradation in fermentation (adjusted R²=0.71).
Proteolytic activity in Pacific whiting and its by-products were investigated
using hemoglobin as substrate. Specific substrates and specific inhibitors were also
used to classify the types of enzymes responsible for protein degradation in fish
sauce fermentation. Serine proteases, cathepsin L-like enzymes and
metalloproteases were active at 50°C in whole fish. However, trypsin-like
enzymes, and cathepsin L-like enzymes were responsible for protein degradation in
by-products at 50°C. At 35°, whole fish was degraded by serine proteases,
cathepsin B-like enzymes, trypsin-like enzymes, and metalloproteases. Cysteine
proteases were mainly responsible for the degradation of proteins in by-products,
and serine proteases and trypsin-like enzymes had a minor role in hydrolyzing of
by-products during fermentation.<br>Graduation date: 2000
42
Piyachomkwan, Kuakoon. "Apparent inhibition of Pacific whiting surimi-associated protease by whey protein concentrate." Thesis, 1993. http://hdl.handle.net/1957/27238.
Full textAbstract:
Surimi is a seafood product which is used to manufacture restructured products
such as artificial crab and lobster. Surimi is produced from fish fillets by washing to
remove sarcoplasmic proteins and increase the concentration of myofibrillar proteins, and
mixing with cryoprotectants. A valuable attribute of surimi is its ability to form an elastic
gel, the gel network being formed by the myofibrillar proteins of fish muscle. It is
generally accepted that the quality of surimi gels is influenced by the activity of
endogenous protease which acts on the myofibrillar proteins. The proteases in Pacific
whiting surimi (Merluccius productus) are particularly problematic due to their high
catalytic activity on muscle myosin. The addition of whey protein concentrate (WPC) to
Pacific whiting surimi has been shown to enhance the gel strength of the corresponding
products produced from this surimi. The mechanism through which WPC enhances the
gel strength of Pacific whiting surimi has not been determined, but it has been suggested
that WPC acts to inhibit surimi autoproteolysis. The objective of this study was to
determine whether the incorporation of WPC into Pacific whiting surimi inhibits
autoproteolysis and/or protects the myosin fraction from proteolytic degradation.
The effect of supplementing surimi with WPC, beef plasma protein (BPP) and
bovine serum albumin (BSA) on its apparent autoproteolysis activity was determined. Three WPC preparations were tested, WPC 34, 34% protein; WPC 80, 80% protein; and
WPC 95, 95% protein. Each of the additives was incorporated at the 1, 2, 3 or 4% level.
Proteolysis of surimi and supplemented surimi samples was allowed to occur at 55°C.
Proteolytic reaction mixtures were terminated by the addition of trichloroacetic acid
(TCA). Proteolytic activity was estimated by measuring the difference in TCA-soluble
peptides present in reaction mixtures of paired (identical) samples, one having been
incubated at 55°C while the paired sample was kept on ice. Peptides were quantified by
the bicinchoninic acid, Lowry, dye-binding and trinitrobenzenesulfonic acid methods.
Results based on the different peptide assays were compared in order to asses the reliance
of results on specific assay methods.
BPP was found to have the most inhibitory activity in the autoproteolysis assays,
followed by the WPC preparations and then BSA. Autoproteolysis was completely
inhibited by the incorporation of 1% BPP, 3% WPC 80 and 2% WPC 95. The extent of
inhibition by the WPC preparations was related to their protein content, the higher the
protein content the greater the extent of inhibition per unit weight added to surimi. BSA
was not an inhibitor of autoproteolysis under the conditions used in this study. The
relative extents of inhibition observed for the different additives were independent of the
method used to quantify the soluble peptide products.
Each of the additives was also tested for their ability to protect the myosin
component of surimi from proteolytic degradation. These experiments were done as
described above for the autoproteolysis assays with the exception that following the
incubation period a portion of the sample, either surimi or a surimi/additive mixture, was
completely solubilized in detergent solution, subjected to SDS-PAGE electrophoresis and
visualized by protein staining. In these experiments the additives were incorporated at the
4% level. No apparent degradation of myosin could be detected over a 60 min reaction
period for surimi samples that were supplemented with BPP, WPC 80 and WPC 95. In
contrast, surimi samples incubated without additive clearly showed a loss of myosin after 15 min reaction period. Some myosin degradation was apparent following the 60 min
incubation period for the WPC 34-supplemented surimi.
A further experiment was conducted to determine the mechanism through which
WPC protects myosin and inhibits autoproteolysis. In this experiment WPC 95 and BPP
were separately incubated at 55°C with a crude fish protease preparation, i.e. the reaction
mixture approximates that used in the autoproteolysis assays except that it contains no
surimi. The results indicate that BPP and WPC 95 behave in a similar manner. However,
the results were inconclusive with regard to explaining the additive's mechanism of action.
Plausible mechanisms which are consistent with the results are discussed.<br>Graduation date: 1994
43
Wu, JuWen. "Kinetic properties and characterization of purified proteases from Pacific whiting (Merluccius productus)." Thesis, 1994. http://hdl.handle.net/1957/27168.
Full textAbstract:
Kinetic properties of the two proteases, causing textural degradation of Pacific
whiting (Merluccius productus) during heating, were compared and characterized with the
synthetic substrate, Z-Phe-Arg-NMec. Pacific whiting P-I and P-II showed the highest
specificity on Z-Phe-Arg-NMec, specific substrate for cathepsin L. The K [subscript m] of
preactivated P-I and P-II were 62.98 and 76.02 (μM), and k [subscript cat], 2.38 and 1.34 (s⁻¹)
against Z-Phe-Arg-NMec at pH 7.0 and 30°C, respectively. Optimum pH stability for
preactivated P-I and P-II is between 4.5 and 5.5. Both enzymes showed similar pH-induced
preactivation profiles at 30°C. The maximal activity for both enzymes was
obtained by preactivating the enzyme at a range of pH 5.5 to 7.5. The highest activation
rate for both enzymes was determined at pH 7.5. At pH 5.5, the rate to reach the
maximal activity was the slowest, but the activity was stable up to 1 hr. P-I and P-II shared similar temperature profiles at pH 5.5 and pH 7.0 studied. Optimum temperatures
at pH 5.5 and 7.0 for both proteases on the same substrate were 55°C. Significant
thermal inactivation for both enzymes was shown at 75°C. Preactivated P-I and P-II
displayed a similar first order thermal inactivation profile at pH 7.0. At 30 and 90°C, half
lives, t [subscript 1/2], for Pacific whiting P-I were 49.50 and 0.20 min and for P-II, 32.54 and 0.18
min, respectively. The rate constant of inactivation for both proteases increased about
200-fold between two limits, 30 and 90°C. Half lives at 55°C, optimum temperature, for
P-I and P-II were also determined to be 5.29 and 6.75 min. The increase in thermal
inactivation rate constants independent of substrates corresponded to an activation energy
for heat denaturation of 21.18 kcal/mol for P-I and 19.97 kcal/mol for P-II by Arrhenius
plot. These similar kinetic properties, i.e., kinetic parameters, pH profile and thermal
inactivation rate constant, suggested that Pacific whiting P-I and P-II are the same
enzyme.<br>Graduation date: 1994
44
Weerasinghe, Vasana C. "Characterization of Pacific whiting protease and food-grade inhibitors for surimi production." Thesis, 1995. http://hdl.handle.net/1957/27070.
Full textAbstract:
Cathepsin B was the most active cysteine proteinase in the Pacific whiting
(Merluccius productus) fish fillet, and cathepsin L in surimi when the activities of the
most active cysteine proteinases (cathepsin L, B, and H) were compared. Cathepsin L
showed maximum activity at 55°C in both fish fillet and surimi, indicating its function
in myosin degradation during conventional cooking of fish fillet and surimi. Washing
during surimi processing removed cathepsin B and H but not cathepsin L. Autolytic
analysis of surimi proteins showed that the myosin was the primary target, while actin
and myosin light chain showed limited hydrolysis during 2 hr incubation. When
purified Pacific whiting proteinase was incubated with various component of fish
muscle, proteinase was capable of hydrolyzing purified myofibrils myosin, and native
and heat-denatured collagen. The degradation pattern of myofibrils by the proteinase
was the same as the autolytic pattern of surimi.
Inhibition by the food-grade proteinase inhibitors varied with the catalytic type
of proteinase. Beef plasma protein (BPP) had a higher percentage of papain inhibitors, followed by whey protein concentrate (WPC), potato powder (PP), and egg white
(EW). On the other hand, EW had a higher percentage of trypsin inhibitors followed
by BPP, PP, and WPC. EW inhibited trypsin activity completely at levels as low as
1%. WPC inhibited the autolytic activity of fresh surimi. Bovine serum albumin
(BSA) was not effective as WPC. WPC can be used as an inhibitor for the Pacific
whiting surimi, but high concentration is required.
A limited number of inhibitory components were found, as the components in
food-grade inhibitors were characterized by inhibitory activity staining. Both EW and
PP showed more serine proteinase inhibitors than cysteine proteinase inhibitors. PP
showed one cysteine inhibitory component while EW did not show any. BSA in both
WPC and BPP acts as an nonspecific competitive inhibitor and reduces the enzyme
activity. An unidentified high molecular weight protein (HMP) found in WPC, BPP,
and BSA functions as an alternative substrate for papain while it functions as true
inhibitor for trypsin.<br>Graduation date: 1995
45
Peters, Margo Y. "Components of bovine plasma that enhance gel strength in Pacific whiting surimi." Thesis, 1995. http://hdl.handle.net/1957/27077.
Full textAbstract:
Proteolysis of myofibrillar proteins in Pacific whiting surimi occurs when the 50-
70°C temperature range is reached during standard cooking procedures (e.g. 90°C for 15
min). This proteolytic activity results in the softening of surimi gels. Bovine plasma
protein (BPP) is the most effective of the food-grade inhibitors used to prevent this
reaction, and enhance gel strength in PW surimi. The objective of this study was to
determine the effective components of bovine plasma that enhance gel strength in PW
surimi.
Five bovine plasma fractions were evaluated for components that contribute to gel
strength enhancement in PW surimi. Fraction I, which consists mostly of fibrinogen and
albumin, was found to also contain plasma transglutaminase (PTGase) activity. Part of
fraction I gel-enhancing ability may be attributed to an unknown component which
inhibited papain independently of Ca²⁺ and inhibited 40% of surimi proteolytic activity.
Fibrinogen or albumin did not inhibit papain activity or enhance gel strength of surimi.
For fraction I-S, which is a more concentrated PTGase fraction, gel-enhancement of PW
surimi was completely dependent on the presence of Ca²⁺. Autolytic inhibitory activity
of fraction I-S in surimi was completely eliminated by the presence of Zn²⁺. Fraction
II+III (1%) inhibited over 50% of surimi autolytic activity and displayed a small amount of PTGase activity. Fraction II+III (1%) gel enhancing abilities were low when
compared to the other fractions and BPP, and only slightly effected by EGTA. Fraction
IV (1%), which contains approximately 50% albumin and 15% α₂-macroglobulin,
inhibited over 70% of surimi autolytic activity. It enhanced gel strength at a 1% (w/w)
concentration when set for 20 hr at 4°C before cooking, and was not affected by EGTA.
This fraction displayed no apparent PTGase activity. Fraction IV-1 (1%), which contains
approximately 20-30% α₂-macroglobulin, gel strength enhancement surpassed the other
fractions and BPP when set for 20 hr at 4°C and 2 hr at 25°C before being cooked at
90°C for 15 min. The gel strength enhancing abilities of fraction IV-1 were
significantly affected by EGTA. Fraction IV-1 (1%) inhibited over 80% of surimi
proteolytic activity. The gel strength of 1 mM (0.03%) E-64, which is a cysteine
protease inhibitor, was equivalent to that of BPP (1%) after setting at 4°C for 20 hrs
before cooking. E-64 (1 mM) inhibited 83% of the autolytic activity of PW surimi and
BPP (1%) inhibited 78%. These data indicate that a cysteine protease inhibitor can
increase gel strength, and suggests that BPP is acting as a cysteine protease inhibitor.
Ca²⁺ dependent gel strength enhancement was attributed to transglutaminase
(TGase) activity, both added PTGase and endogenous TGase. Gel strength enhancement
that was Ca²⁺ independent was attributed to cysteine protease inhibitors, specifically α₂-macroglobulin.
Overall, it was determined that gel strength in PW surimi was greatly
enhanced by both concentrated PTGase (I and I-S) and concentrated α₂-macroglobulin
(IV-1) fractions, with a combination of these fractions being most effective in gel
strength enhancement, when the surimi is first set at 4°C or 25°C before cooking at 90°C
for 15 min. These data suggest that the mechanisms of gel strength enhancement of BPP
are from cysteine protease inhibition, possibly from α₂-macroglobulin, and from crosslinking
of myosin in surimi from both added (PTGase) and endogenous TGase activity.<br>Graduation date: 1996
46
Magnusdottir, Edda. "Physical and chemical changes in stabilized mince from Pacific whiting during frozen storage." Thesis, 1995. http://hdl.handle.net/1957/27109.
Full textAbstract:
Cryoprotection in stabilized mince from Pacific whiting (Merluccius productus)
was investigated by monitoring changes in physical and chemical properties during 32
weeks of frozen storage. The effects of 4 different cryoprotectants were evaluated by
torsion test, color analysis, extractability of salt soluble proteins, and formation of
dimethylamine (DMA) and 2-thiobarbituric acid (TBA). The quality of the stabilized
mince was significantly higher than the control (mince without cryoprotectants) when
compared by shear strain, salt soluble proteins, and DMA. The results show that the
functionality of the proteins in the mince can be protected by using cryoprotectants
with Polydextrose® being the most effective of the 4 tested. The effect of food-grade
protease inhibitors on the gel-forming characteristics of Pacific whiting mince was also
investigated. Four levels (1, 2, 3, and 4%) of different protease inhibitors (beef
plasma protein, whey protein concentrate, egg white liquid, and egg white powder)
were added to the stabilized mince before heating and effects on texture and color
were evaluated. Shear strain was significantly increased by increasing the level of inhibitors. Beef plasma protein was most effective and presented significantly higher
strain than the other inhibitors tested. Due to higher concentration of proteolytic
enzymes in the mince, an increased amount of protease inhibitors is needed compared
to surimi to prevent proteolysis during heating.<br>Graduation date: 1995
47
Tungkawachara, Somjintana. "Characterization of biochemical, functional properties, and market potential of Pacific whiting fish sauce." Thesis, 2003. http://hdl.handle.net/1957/27114.
Full textAbstract:
Biochemical properties, functional properties, and market potential of
Pacific whiting (PW) fish sauce were investigated. Biochemical properties of fish
sauce made from whole fish (W) and a mixture (1:1) of whole fish and surimi
byproducts (WB) were compared. Market potential was evaluated through phone
interviews and consumer panelists. Proteolysis was primarily affected by cathepsin B-like
and L-like enzymes. Acidic pH (4-5) with low salt concentration (15-20%)
provided a greater degree of hydrolysis (DH), total nitrogen, and amino nitrogen
content in PW fish sauce compared to the traditional process. The greatest
Angiotensin Converting Enzyme (ACE) inhibition (96.8%) was found in samples
fermented with 15% salt at pH 5.0 for 30 days. Anti-oxidative activity (AT) increased
when fermentation continued and depended on fermentation pH. Peptides with MW
<590 Da possibly played an important role in ACE inhibition. Consumer tests
disclosed no significant difference in flavor liking and overall liking among fish sauce
samples (W, WB, and commercial anchovy fish sauce).<br>Graduation date: 2004
48
Chang-Lee, Maria Virginia. "The production of surimi from Pacific whiting (Merluccius productus) and evaluation of kamaboko gels." Thesis, 1988. http://hdl.handle.net/1957/27169.
Full textAbstract:
Yield, proximate composition, and proteolytic activity were
determined in each unit operation during production of surimi from
Pacific whiting. Preliminary studies involved the addition of protein
adjuncts such as egg white (EW), whey protein concentrate (WPC), and soy
protein isolate (SPI), at different levels, to kamaboko gels in order to
select the main protein for further study. SDS-gel electrophoresis was
performed to evaluate the effectiveness of egg white as a protease
inhibitor in kamaboko gels.
Yields obtained from planked fish (42.4%) and minced flesh (35.7%)
agree with those values reported from other studies in whiting. A
reduced washed flesh yield was expected since washing is done to remove
those constituents not desirable in surimi. Lower yields resulted in
the refined flesh (17.4%), and surimi (19.9%). Proximate composition
values through the unit operations were similar with other studies done
with whiting, and were compared with other fish species indicating
acceptable nutritional quality. Deboned and washed flesh (first wash)
were significantly different in protease activity from the flesh (second wash) and refined product (P<0.05). This demonstrates the importance of
the washing process in surimi unit operations.
Protein adjuncts (EW, WPC, and SPI) in kamaboko gels at levels of 1
to 5% were evaluated based on hardness, cohesiveness and elasticity.
Addition of egg white at levels ranging from 3 to 5% resulted in greater
hardness (P<0.05), and elasticity (P<0.005) in comparison with WPC and
SPI. Therefore EW at 3% level was selected for additional study.
Two stage heat treatments at 40°C at varying times followed by a
90°C for 20 min were tested with kamaboko gels containing 3% EW. No
significant differences were found in hardness and elasticity compared
to a one stage heat treatment at 90°C for 40 min (P<0.01). Based on
this study, a one stage heat treatment was selected for the cooking of
kamaboko gels.
Potato starch at a level of 5% was also included in the following
formulations due to its property to increase binding and elasticity. An
increased hardness of 154% and elasticity 464% in kamaboko gels
containing 3% EW was found compared to the control. An increase of 9%
in hardness, and 23% in elasticity was found in gels containing 3% EW
and 5% potato starch compared to gels containing only 3% EW. A
significant difference was found in expressible moisture within the
three formulations (P<0.03) due to the addition of the ingredients and
their binding properties.
Egg white proved to have an inhibiting effect on proteolytic
activity in kamaboko gels. This was demonstrated by SDS
gel-electrophoresis in which the myosin band was present in formulations
containing 3% egg white and indicated that no enzymatic breakdown was
taking place.<br>Graduation date: 1988
49
Chung, Yun-Chin. "Effect of salt and pH on surimi gels made from Pacific whiting (Merluccius productus)." Thesis, 1993. http://hdl.handle.net/1957/27181.
Full textAbstract:
The effect of salt (0, 0.9, 1.7, 2.5%) and pH (range 4
to 10) on surimi gels made from Pacific Whiting (Merluccius
productus) was investigated. Gel-forming ability was measured
by the torsion test. In general, surimi gels
increased in gel strength with increased pH. Breaking shear
stress increased to a greater degree than breaking shear
strain above pH 7.0. The increase in gel strength was
greater at higher pHs for gels made without salt than those
made with salt. At neutral pH, the salted surimi showed
greater gel forming abilities than the unsalted whiting
surimi. Poor gels were formed at low pH (pH 4 to 6) for
both the salted and no-salt surimi. These results
demonstrated that pH and salt concentration had an interactive
effect on the gel-forming ability of the Pacific whiting
surimi and that improved gel strength at low salt levels
might be obtained by increasing the pH.<br>Graduation date: 1993
50
Peters, Gregory J. "Determination of quality parameters for the Pacific whiting fishery using neural network and induction modeling." Thesis, 1995. http://hdl.handle.net/1957/34581.
Full textAbstract:
Pacific whiting, with a maximum sustainable yield between 150,000 and
250,000 metric tons, is the largest stock of fish found off Oregon. The majority of the
fish are processed into surimi. Hundreds of variables could potentially affect surimi
quality (gel strength). Alternative harvesting and processing input combinations, as
well as product quality attributes and their influences, were collected for the 1992-94
Pacific whiting seasons. This data was combined with other research on Pacific
whiting quality to develop a comprehensive model of the Pacific whiting fishery.
Neural network and induction modeling methods were used to isolate the importance
of each input variable and document its interactive effects on other variables. Neural
network modeling does not have the limitations of standard modeling techniques. A
neural network model can "learn" and adjust weights among inputs and interactions as
situations change. This allows for development of models which assign weights to all
inputs, yet is easily maintained and updated.
Another modeling method, known as induction, divides the information into
smaller, more defined, subgroups which are analyzed separately using regression. This
strategy reduces complications due to discontinuities in the data. A hybrid model was
developed by combining results of the two modeling methods.
These methods were compared to multiple regression for their effectiveness in
prediction. The hybrid model provided the most accurate predictions (96% of
predictions within 10% of actual value), followed by neural networks (92%), induction
(84%), and regression (74%).
Of the 88 variables examined, only ten and their interactions were significantly
related to final product quality. These variables include the time it takes to process
the fish from capture, the temperature the fish are stored until processing, the salinity,
moisture content, and pH of the fish, the length and weight of the fish, the date and
place where the fish were captured, and the water:meat wash ratio of the various
surimi washes during processing. Most of the variables were highly interactive and
nonlinear.
The information derived from these models can be used to optimize production
decisions and maximize profit. Quality influences of Pacific whiting are crucial for
long term production and can be used to benefit the entire industry.<br>Graduation date: 1996