The purpose of this study was twofold: 1) to identify commercially available feeds that could serve as suitable replacements for newly hatched Artemia in the diets of L. vannamei from Z3/M1 to PL10 without significantly affecting survival, final length and weight, and quality of the larvae and 2) to identify an ideal substitution rate between live Artemia and a replacement feed that maximizes feed and labor costs savings, survival, and PL quality. In Experiment 1, two commercially available Artemia replacement feeds, Zeigler EZ Artemia and Bernaqua Vitellus, were administered according to manufacturer’s guidelines in order to identify which feed served as a more suitable replacement diet. In Experiment 2, the more successful feed from Experiment 1 was administered in three different co-feeding strategies, in which the inert feed replaced a certain percentage of live Artemia. Mean percent survival was not significantly different between the Control, EZ Artemia, and Vitellus treatment groups in Experiment 1 (P<0.05). Both the EZ Artemia and Vitellus treatments yielded significantly different final mean lengths (mm) and weights (mg) from the Control group. The Vitellus feed results for all performance factors (mean percent survival, final length (mm), final weight (mg), and percent stress test mortality) were not significantly different than those of the EZ Artemia treatment, despite receiving no Artemia during the culture period, while the EZ Artemia treatment received 75% Artemia from PL5-PL10. For these reasons, the Vitellus feed was selected as the more successful feed in Experiment 1. In Experiment 2, there was no significant difference between the four treatment groups (Control, V50, V100/50, and V100/75) for mean percent survival and percent stress test mortality (P<0.05). The V100/50 and V100/75 treatments’ mean final lengths (mm) and weights (mg) were significantly different than those of the Control treatment. There were no significant differences between the V50, V100/50, and V100/75 treatments for any of the observed performance factors. These results indicate that the maximum substitution rate of Vitellus for Artemia in this experiment (the V100/75 treatment) was successful in replacing 84.33% of newly hatched Artemia in the larval culture of L. vannamei from Z3/M1-PL10 without resulting in significantly different survival and stress test mortalities compared to the Control group. Feeding schedules such as V100/75 treatment help streamline production efforts in commercial operations and result in increased production cost savings when compared to other replacement feeding schedules that begin in the early mysis stages. The V100/75 feeding schedule influences variable feed and labor costs the greatest because farmers are able to delay the culturing of Artemia an additional 7 days (until PL5) from what is typically performed in larviculture facilities.

Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

QC20100709

I dagens samhälle ökar våldsbrotten bland ungdomar och våld, hot, mobbning och vandalism är vanligt förekommande. Vi har valt att titta på aggressioner hos ungdomar ur olika perspektiv, främst inlärningsteori och kognitiv teori. Samhället behöver ge ungdomar verktyg för att kunna agera annorlunda än med aggression i olika situationer, ett sätt är behandlingsmetoden ART. ART (Aggression Replacement Training) är en behandlingsmodell som syftar till att ge personer sociala alternativ till ilska och aggressioner. Genom ett antal kvalitativa intervjuer på två SIS-institutioner, där ungdomar med tung social problematik är placerade genom LVU och LSU, har vi försökt komma underfund med vad ungdomarna som genomgått behandlingen har för åsikter om den och om de själva tror sig kunna ha nytta av behandlingen även i framtiden. Vi har också undersökt behandlarens roll, och vad ungdomarna tyckte om behandlarna. Resultatet av intervjuerna är mycket positivt, ungdomarna var i allmänhet mycket positiva till metoden och kom även med förslag på hur den skulle kunna göras bättre. Efter att ha gjort halvstrukturerade kvalitativa intervjuer användes en manifest innehållsanalys för att analysera de svar vi fått under intervjuerna.

The thesis will provide a description of the previous Swedish NRT marketing mix, a description of the present plans of Swedish NRT marketers for the marketing mix of their products, and the present marketing mix of the previously deregulated pharmacy markets in Finland and Norway. The purpose is to develop conclusions on how marketers of NRT products could change their marketing mix in response to the deregulation of the Swedish pharmacy market.    This thesis relies on a descriptive method. Interviews are used as the source of primary data. This is because some of the information sought after is not readily available and cannot be found through secondary data. Markets are mature only in the minds of the actors on the market. Due to the deregulation the market seems to be a window of opportunity for any innovative, aggressive marketing entrepreneur who wants to radically change his or her position in the market. NRT marketers could attempt to design a new, more aggressive strategy and work with the remaining Ps to unhinge what seems to be regarded a mature market. NRT marketers should work more actively to create an effective market feedback loop. NRT marketers should consider using the Internet to sell their products to consumers, thus opening a new channel.

<p>Because of the slow access time of disk storage, storage management is crucial to the performance of many large scale computer systems. This thesis studies performance issues in buffer cache management and disk layout management, two important components of storage management. </p><p>The buffer cache stores popular disk pages in memory to speed up the access to them. Buffer cache management algorithms used in real systems often have many parameters that require careful hand-tuning to get good performance. A self-tuning algorithm is proposed to automatically tune the page cleaning activity in the buffer cache management algorithm by monitoring the I/O activities of the buffer cache. This algorithm achieves performance comparable to the best manually tuned system.</p><p>The global data structure used by the buffer cache management algorithm is protected by a lock. Access to this lock can cause contention which can significantly reduce system throughput in multi-processor systems. Current solutions to eliminate lock contention decrease the hit ratio of the buffer cache, which causes poor performance when the system is I/O-bound. A new approach, called the multi-region cache, is proposed. This approach eliminates lock contention, maintains the hit ratio of the buffer cache, and incurs little overhead. Moreover, this approach can be applied to most buffer cache management algorithms.</p><p>Disk layout management arranges the layout of pages on disks to improve the disk I/O efficiency. The typical disk layout approach, called Overwrite, is optimized for sequential I/Os from a single file. Interleaved writes from multiple users can significantly decrease system throughput in large scale systems using Overwrite. Although the Log-structured File System (LFS) is optimized for such workloads, its garbage collection overhead can be expensive. In modern and future disks, because of the much faster improvement of disk transfer bandwidth over disk positioning time, LFS performs much better than Overwrite in most workloads, unless the disk is close to full. A new disk layout approach, called HyLog, is proposed. HyLog achieves performance comparable to the best of existing disk layout approaches in most cases.

In Canada, nicotine replacement therapy (NRT) is a best practice for adult smoking cessation, but it is not recommended for use by youth smokers. Previous research has indicated that more than 20 percent of high school-aged smokers in Canada had used NRT, despite the cross-Canada requirement that youths under the age of 18 have a physician’s prescription to purchase NRT. The goal of this study was to examine both student and school-level characteristics associated with use of NRT by youths. Data from 29,296 grade 9 to 12 students who participated in the 2008-2009 National Youth Smoking Survey (YSS) were combined with Canadian census and built environment data in multilevel logistic regression models. The associations between lifetime and current NRT use with student characteristics (i.e., smoking status, social smoking connections) were examined alongside school environment factors such as urban/rural location and pharmacy density within a one kilometre radius of schools. In 2008-2009, 21.1% of youth smokers in Canada had ever used NRT and 5.1% were currently using NRT. Odds of NRT use were highest among daily smokers, boys, youths who had made multiple quit attempts, and youths who self-identified as smokers. Attending a school located within an urban area increased youths’ odds of NRT use, whereas higher density of pharmacies surrounding a school was inversely associated with NRT use. This study is the first to identify significant between school differences in NRT use. It also reveals that many youths are using NRT in the absence of a quit attempt. Further research is needed to identify school characteristics that impact NRT use, and understand how youths are accessing NRT.

<p>Because of the slow access time of disk storage, storage management is crucial to the performance of many large scale computer systems. This thesis studies performance issues in buffer cache management and disk layout management, two important components of storage management. </p><p>The buffer cache stores popular disk pages in memory to speed up the access to them. Buffer cache management algorithms used in real systems often have many parameters that require careful hand-tuning to get good performance. A self-tuning algorithm is proposed to automatically tune the page cleaning activity in the buffer cache management algorithm by monitoring the I/O activities of the buffer cache. This algorithm achieves performance comparable to the best manually tuned system.</p><p>The global data structure used by the buffer cache management algorithm is protected by a lock. Access to this lock can cause contention which can significantly reduce system throughput in multi-processor systems. Current solutions to eliminate lock contention decrease the hit ratio of the buffer cache, which causes poor performance when the system is I/O-bound. A new approach, called the multi-region cache, is proposed. This approach eliminates lock contention, maintains the hit ratio of the buffer cache, and incurs little overhead. Moreover, this approach can be applied to most buffer cache management algorithms.</p><p>Disk layout management arranges the layout of pages on disks to improve the disk I/O efficiency. The typical disk layout approach, called Overwrite, is optimized for sequential I/Os from a single file. Interleaved writes from multiple users can significantly decrease system throughput in large scale systems using Overwrite. Although the Log-structured File System (LFS) is optimized for such workloads, its garbage collection overhead can be expensive. In modern and future disks, because of the much faster improvement of disk transfer bandwidth over disk positioning time, LFS performs much better than Overwrite in most workloads, unless the disk is close to full. A new disk layout approach, called HyLog, is proposed. HyLog achieves performance comparable to the best of existing disk layout approaches in most cases.

In this dissertation, we investigate methods of modifying a tight frame sequence on a finite subset of the frame so that the result is a tight frame with better properties. We call this a surgery on the frame. There are basically three types of surgeries: transplants, expansions, and contractions. In this dissertation, it will be necessary to consider surgeries on not-necessarily-tight frames because the subsets of frames that are excised and replaced are usually not themselves tight frames on their spans, even if the initial frame and the final frame are tight. This makes the theory necessarily complicated, and richer than one might expect. Chapter I is devoted to an introduction to frame theory. In Chapter II, we investigate conditions under which expansion, contraction, and transplant problems have a solution. In particular, we consider the equiangular replacement problem. We show that we can always replace a set of three unit vectors with a set of three complex unit equiangular vectors which has the same Bessel operator as the Bessel operator of the original set. We show that this can not always be done if we require the replacement vectors to be real, even if the original vectors are real. We also prove that the minimum angle between pairs of vectors in the replacement set becomes largest when the replacement set is equiangular. Iterating this procedure can yield a frame with smaller maximal frame correlation than the original. Frames with optimal maximal frame correlation are called Grassmannian frames and no general method is known at the present time for constructing them. Addressing this, in Chapter III we introduce a spreading algorithm for finite unit tight frames by replacing vectors three-at-a-time to produce a unit tight frame with better maximal frame correlation than the original frame. This algorithm also provides a “good” orientation for the replacement sets. The orientation part ensures stability in the sense that if a selected set of three unit vectors happens to already be equiangular, then the algorithm gives back the same three vectors in the original order. In chapter IV and chapter V, we investigate two special classes of frames called push-out frames and group frames. Chapter VI is devoted to some mathematical problems related to the ”cocktail party problem ”.

Scales are a visually striking feature that grows on many animals. These small, rigid plates embedded in the skin form an integral part of our description of fish and reptiles, some plants, and many extinct animals. Scales exist in many shapes and sizes, and serve as protection, camouflage, and plumage for animals. The variety of scales and the animals they grow from pose an interesting problem in the field of Computer Graphics. This dissertation presents a method for generating scales and scale-like structures on a polygonal mesh through surface replacement. A triangular mesh was covered with scales and one or more proxy-models were used as the scales shape. A user began scale generation by drawing a lateral line on the model to control the distribution and orientation of scales on the surface. Next, a vector field was created over the surface to control an anisotropic Voronoi tessellation, which represents the region occupied by each scale. Then these regions were replaced by cutting the proxy model to match the boundary of the Voronoi region and deform the cut model onto the surface. The final result is a fully connected 2-manifold that is suitable for subsequent post-processing applications, like surface subdivision.