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Growth Rates in Gulf of Mexico Red Snapper, <em>Lutjanus campechanus</em>, Before and After the <em>Deepwater Horizon</em> BlowoutHerdter, Elizabeth Shea 05 November 2014 (has links)
The Deepwater Horizon blowout occurred on April 20th, 2010 and released nearly 5 million barrels of crude oil into the northern Gulf of Mexico causing pollution of the water and sediment inhabited by many fishes for at least 87 days while the wellhead went uncapped. Populations of the Gulf of Mexico Red snapper, Lutjanus campechanus, an important fish to the ecology and economy in the region, exhibit affinity to shallow water oil infrastructure such as the Deepwater Horizon making them especially vulnerable to crude oil contamination. The objective of this study is to determine growth of Red snapper before, during and after the DWH spill and to assess factors potentially explaining such growth variation. Sagittal otoliths were collected from individuals sampled in 2011 - 2013 from scientific, demersal long-line surveys in the northern Gulf of Mexico (GoM) and West Florida Shelf (WFS). Age and otolith increment width analyses were performed. No annual variation in von Bertalanffy growth parameters was determined among the three catch years. The L∞ , K and t0 estimated from the complete data set (2011-2013) were 82.91, 0.20 and 0.43, respectively. However, significant differences in otolith increment width-at-age were observed in increment numbers three - seven in years following the DWH event, with declines of 13%, 15% and 22% occurring in the fourth -sixth increments. To asses the potential significance of exogenous environmental variables to observed yearly growth variation I evaluated five parameters - meridional (V) winds, zonal (U) winds, wind stress curl which is a measure of upwelling, Mississippi River discharge, and mean sea level anomaly - using a linear mixed effects model. Hypothesis testing via reduced maximum likelihood estimates indicated that variation in U winds and River discharge could significantly explain the variation in increment width. However, further work must be done in order to determine the natural, inter-annual variability in age specific growth before the results from model fitting can be considered conclusive. Mean back-calculated weight-at-age measurements were obtained in order to assess potential variation in productivity changes. Results from forward difference and reverse helmert contrast-coding indicated that weight at age three+, four+ and five+ declined by 16%, 15% and 11% in 2010, respectively. These analyses indicate a significant decline in fish growth in 2010 coincident with the DWH event, followed by a return to pre-spill rates.
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Influence of Chloride-induced corrosion cracks on the strength of reinforced concreteTang, Denglei, Denglei.Tang@gmail.com January 2008 (has links)
In marine environments and where de-icing salts are applied, the degradation of reinforced concrete structures due to chloride induced corrosion of the reinforcement is a major problem. The expansive nature of the corrosion process results in cracking of the concrete and eventually spalling. In order to select suitable remedial measures it is necessary to make an assessment of the residual strength and the residual life. In order to investigate the effect of corrosion on bond strength of the reinforcement, specimens comprising square prismatic sections containing steel reinforcement in the four corners have been subjected to a wet-dry cycle and corrosion has been accelerated by polarising the bars. The research has studied the change of bond strength with level of corrosion for 12 mm and 16 mm bars with concrete cover of 1 and 3 times the bar size. The bond strength is assessed by means of pull out tests and the corresponding extent of corrosion has been assessed in terms of the mass loss. Observations and measurements of the form of the corrosion (pit dimensions and loss of bar diameter) are also presented. The relationship between bond strength and surface crack width has been investigated. Results show that the surface crack width may be a good indicator of residual bond strength. In addition, the influence on bond strength of concrete compressive strength, reinforcement cover, bar position and bar size on the change of bond strength has been explored. It should be noted that all conclusions drawn in this project are based on tests on specimens without shear reinforcement (unconfined) and that accelerated corrosion (by impressed current) has been adopted. Consequently, care should be exercised in applying these results directly to structures in the field. Additional research is needed to assess the influence of impressed current on crack patterns and the effect of shear reinforcement.
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Two and three dimensional cephalometric assessment of dental and skeletal changes following orthodontic treatment with Damon passive self-ligating systemEhsani, Sayeh 06 1900 (has links)
Objectives: The aim of this study was to evaluate dental and/or skeletal changes following orthodontic treatment with Damon self-ligating (SL) brackets in non-extraction patients.
Methods: Frontal and lateral cephalomteric radiographs of 20 patients before and after non-extraction treatment with Damon SL brackets were analyzed in a three-dimensional analysis computer program (3DCeph, UIC, IL., USA). Changes of intermolar and intercanine distances, incisor positions and maxillary basal bone width of Damon treated subjects were compared to corresponding untreated controls (Bolton templates). Comparisons between the two groups were made with Nonparametric (Mann-Whitney U) test.
Results and Conclusions: Transverse changes in distances between crowns of upper and lower first molars and canines in Damon group were similar to untreated individuals (P >0.01). However, in Damon group distances between roots of upper molars and lower canines increased 4.59 and 3.49 mm respectively, compared with 0.8 and -0.01 mm in the Control group (P <0.001, P= 0.001). Lingual root torque of upper incisors and proclination of lower incisors were larger in the Damon group (P<0.05). Damon treatment did not result in buccal tipping of molar crowns or maxillary base width increase (P>0.05). Overall, teeth alignment with Damon system was accomplished with a combination of arch width changes and incisor proclination and/or lingual root torque.
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A neural network face detector design using bit-width reduced FPU in FPGALee, Yongsoon 05 February 2007
This thesis implemented a field programmable gate array (FPGA)-based face detector using a neural network (NN), as well as a bit-width reduced floating-point unit (FPU). An NN was used to easily separate face data and non-face data in the face detector. The NN performs time consuming repetitive calculation. This time consuming problem was solved by a Field Programmable Gate Array (FPGA) device and a bit-width reduced FPU in this thesis. A floating-point bit-width reduction provided a significant saving of hardware resources, such as area and power.<p>The analytical error model, using the maximum relative representation error (MRRE) and the average relative representation error (ARRE), was developed to obtain the maximum and average output errors for the bit-width reduced FPUs. After the development of the analytical error model, the bit-width reduced FPUs and an NN were designed using MATLAB and VHDL. Finally, the analytical (MATLAB) results, along with the experimental (VHDL) results, were compared. The analytical results and the experimental results showed conformity of shape. It was also found that while maintaining 94.1% detection accuracy, a reduction in bit-width from 32 bits to 16 bits reduced the size of memory and arithmetic units by 50%, and the total power consumption by 14.7%.
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Genrebreddens betydelse i violinundervisning / The Importance of Genres in Violin TeachingOlsson, Therese January 2012 (has links)
Problemformuleringen i denna studie är ”Hur uppfattar fiollärare genrebreddens betydelse för elevers fortsatta musikintresse och utveckling?” Hur bemöter musikskolan den musikaliska evolutionen? Den evolution vilken, i och med 1900-talets paradigmskifte, fört det musikaliska synsättet från det traditionella mot ett allt mer öppet klimat i musikundervisningen. För att få svar på detta vände jag mig till fyra fiollärare med fiollärarutbildning och använde den kvalitativa intervjun som metod. Samtliga informanter hade erfarenhet inom yrket. Resultatet av undersökningen visar att lärarna upplever elevernas musikidentitet mycket starkare än förr, vilket resulterar i att låtvalet är väldigt viktigt. Att välja rätt låt är inte helt lätt, med tanke på att det för eleverna är väldigt viktigt att få spela musik från den egna ungdomskulturen. - Låtar som lärarna inte är så fascinerade av men som dock bevarar elevernas intresse. I slutsatsen har jag jämfört vad mina informanter har sagt i förhållande till vad tidigare forskning kring låtvalet påvisat. - Jämförelsen visar att lärarnas ord bekräftas av forskningen och vise versa. Däremot har min ursprungliga frågeställning fått en annan vinkling än vad jag trodde från början. Som slutsats hävdar jag att det inte är genrebredden i sig som är viktig – det primära i undervisningen är låtvalet, i förhållande till elevernas ungdomskultur. Alltså behöver lärarutbildningen förse de blivande lärarna med kunskaper i alla genrer, för att kunna tillmötesgå den enskilda elevens önskemål. I och med detta anser jag att vi också behöver anpassa musikskolan efter detta – eleverna måste få spela sina önskelåtar! / The main question in this study is “how do violin teachers understand the meaning of genre width for students’ interest of music and development?” How does the music school answer to the musical evolution? Through the paradigm shift during the 20th century, the traditional music culture developed into a more opened-minded musical perspective. In order to answer this question, I asked four educated violin teachers through qualitative interviews. All of the teachers had work experience. The result of the study shows that teachers experience that the student’s music identity is a much more broad than before, which means that the selection of tunes are very important. It is not easy to choose tunes since the students think it is important to play music from their own youth culture. These tunes are often not appreciated by the teachers but very important in order to prohibit students from losing interest. In the conclusion, I compared the interviewed teachers with earlier research in the subject. – The comparison shows that the teachers’ word is confirmed by the science and vice versa. On the other hand, my original question has changed. It is not the genre width itself that is important – the important thing is the choice of tune, in relation to the student’s youth culture. Therefore, teacher education must provide future teachers with knowledge in all genres, to be able to comply with each individual student’s wishes. According to my conclusion we need to refine the music school – the students have to be able to play their favourite tunes.
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A neural network face detector design using bit-width reduced FPU in FPGALee, Yongsoon 05 February 2007 (has links)
This thesis implemented a field programmable gate array (FPGA)-based face detector using a neural network (NN), as well as a bit-width reduced floating-point unit (FPU). An NN was used to easily separate face data and non-face data in the face detector. The NN performs time consuming repetitive calculation. This time consuming problem was solved by a Field Programmable Gate Array (FPGA) device and a bit-width reduced FPU in this thesis. A floating-point bit-width reduction provided a significant saving of hardware resources, such as area and power.<p>The analytical error model, using the maximum relative representation error (MRRE) and the average relative representation error (ARRE), was developed to obtain the maximum and average output errors for the bit-width reduced FPUs. After the development of the analytical error model, the bit-width reduced FPUs and an NN were designed using MATLAB and VHDL. Finally, the analytical (MATLAB) results, along with the experimental (VHDL) results, were compared. The analytical results and the experimental results showed conformity of shape. It was also found that while maintaining 94.1% detection accuracy, a reduction in bit-width from 32 bits to 16 bits reduced the size of memory and arithmetic units by 50%, and the total power consumption by 14.7%.
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Two photon luminescence from quantum dots using broad and narrowband ultrafast laser pulsesBalasubramanian, Haribhaskar 15 May 2009 (has links)
Nonlinear optical microscopy (NLOM) offers many advantages when imaging
intact biological samples. By using ultrafast lasers in the near infrared and two photon
excitation (TPE), signal production is limited to the focal volume and provides an
excellent means for rendering thin, microscopic images from within the sample.
Exogenous fluorophores/lumiphores may be used as efficient contrast agents to tag
specific targets and provide enhanced signal. The efficiency of the TPE process in these
contrast agents is broadly assumed to vary inversely with the laser pulsewidth, τ.
In this work, we investigate the TPE efficiency of transform limited broadband
(~133nm, ~10fs) and narrowband (~11nm, ~170fs) pulses in the generation of twophoton
luminescence from semiconductor nanocrystals or quantum dots (QD’s) both
theoretically and experimentally. Compared to standard organic dyes, QD’s possess a
relatively broad, uniform spectral response that enables better use of the full bandwidth
from the broadband laser.
Theoretical calculations including both degenerate and non-degenerate TPE
indicate a rolloff from the 1/τ behavior as the pulses’ spectral bandwidth becomes
broader than the absorption spectra of the QD’s. Experimentally measured enhancement in luminescence intensity while using a broadband pulse is compared with the simulated
enhancement in two-photon luminescence.
A combination of increased understanding of the excitation processes in NLOM
and proper selection of contrast agents will help in advancing the role of broadband
ultrafast lasers in NLOM.
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Two photon luminescence from quantum dots using broad and narrowband ultrafast laser pulsesBalasubramanian, Haribhaskar 10 October 2008 (has links)
Nonlinear optical microscopy (NLOM) offers many advantages when imaging
intact biological samples. By using ultrafast lasers in the near infrared and two photon
excitation (TPE), signal production is limited to the focal volume and provides an
excellent means for rendering thin, microscopic images from within the sample.
Exogenous fluorophores/lumiphores may be used as efficient contrast agents to tag
specific targets and provide enhanced signal. The efficiency of the TPE process in these
contrast agents is broadly assumed to vary inversely with the laser pulsewidth, τ.
In this work, we investigate the TPE efficiency of transform limited broadband
(~133nm, ~10fs) and narrowband (~11nm, ~170fs) pulses in the generation of twophoton
luminescence from semiconductor nanocrystals or quantum dots (QD's) both
theoretically and experimentally. Compared to standard organic dyes, QD's possess a
relatively broad, uniform spectral response that enables better use of the full bandwidth
from the broadband laser.
Theoretical calculations including both degenerate and non-degenerate TPE
indicate a rolloff from the 1/τ behavior as the pulses' spectral bandwidth becomes
broader than the absorption spectra of the QD's. Experimentally measured enhancement in luminescence intensity while using a broadband pulse is compared with the simulated
enhancement in two-photon luminescence.
A combination of increased understanding of the excitation processes in NLOM
and proper selection of contrast agents will help in advancing the role of broadband
ultrafast lasers in NLOM.
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Beach Buffer Width Requirement Subject to Storm WaveLin, Wen-hua 25 July 2009 (has links)
With increasing demands on environmental protection in recent years, the Government agency concerned has recently proposed the strategies for shore protection and management, which aim for prevention and mitigation of coastal disaster and reduction in coastal erosion, as well as the creation of an environment with focus on landscape, ecology and community recreation. Soft and quasi-natural approach will be implemented to restore the glory of a stable coast.
Based on the consideration of disaster prevention, this study investigates the beach profile changes, which include beach berm erosion and bar formation resulting from storm waves with different return periods. The SBEACH model is used to estimate the beach changes subject to variable conditions of beach berm width, medium sand grain diameter, beach slope and design water level etc. Regression analysis is then applied to establish a relationship between the storm beach buffer width and relevant physical parameters. Prior to this, the results of large wave tank tests on beach profile changes conducted by Coastal Engineering Research Center in the United States are used to calibrate the two main parameters K and £` used in SBEACH model.
Beach profile changes can now be estimated systematically using a set of modified K and £` values. After having performed a series numerical studies, we may conclude that: (1) With storms of different return periods but identical non-dimensional fall velocity (H0/£sT), berm erosion increases and the location of the bar becomes further offshore as storm return period increases ; (2) With different sand grain sizes subject to identical storm wave conditions, beach berm erosion increases as grain size increased, but shoreline retreat decreases; and location of bar is further offshore for a beach consisting smaller sand grains; (3) Under the same storm return period and sand grain diameter (i.e., similar non-dimensional fall velocity), berm erosion increases as storm intensity and design water level increase, but shoreline retreat decreases and bar is located nearer; and vice versa; (4) from a series of calculations based on different sand grains and storm beach buffer width, it is found that larger buffer is required for beach with smaller grain size, in order to absorb the storm wave energy.
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An investigation into the factors involved in preparation and weaving affecting the length and width of woven cloth : effect of warping and weaving tensions, warp control devices, and relaxation processes on warp and weft modular length and thread spacings : the influence of beat-up force and cloth-fell distanceBasu, Asok Kumar January 1980 (has links)
So far the theoretical approach to weaving resistance and fabric geometry and the factors affecting it have been made for such weaves as plain, hop-sack and warp and weft faced ribs. In this work theoretical models were adopted to determine the fabric geometry and weaving resistance. Experimental and theoretical findings are in agreement. The trends of the effects on values of weaving resistance of such factors as warp elastic constant, weft tension, warp tension, the coefficient of friction of yarn against. yarn agree with the trends obtained by other workers by showing that weaving resistance increases with these factors. The results-also show that-the fabric geometry depends on warp and weft tension at-the moment of beat-up. Additionally, the change of fabric geometry across the fabric, the effect of two different let-off mechanisms,, Hattersley and WIRA/Poole, and the beaming CO processes on weaving resistance and fabric geometry were investigated. It was found that the fabric width-depends on the dynamics of fabric formation before and at the moment of beat-up.
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