SiteWit Corporation: SQL or NoSQL that is the Question

This teaching case focuses on a start-up company in the Web analytics and online advertising space, which faces a database scaling challenge. The case covers the rapidly emerging NoSQL database products that can be used to implement very large distributed databases. These are exciting times in the database marketplace, with a flock of new companies offering scalable database systems for the cloud. These products challenge the existing relational database vendors that have come to dominate the market. The case outlines four potential solutions and asks students to make a choice or suggest a different alternative

A Dynamic Query-Rewriting Mechanism for Role-Based Access Control in Databases

Although Role-Based Access Control (RBAC) is a common security model currently, it has not been systematically applied in databases. In this paper, we propose a framework that enforces RBAC based on dynamic query rewriting. This framework grants privileges to data based on an intersection of roles, database structures, content, and privileges. All of this is implemented at the database level, which also offers a centralized location for administering security policies. We have implemented the framework within a healthcare setting

Goal Attainment on Long Tail Websites: An Information Foraging Approach

Information foraging theory (IFT) has emerged within the previous decade as a way of explaining the behavior of individuals as they hunt for information (Pirolli, 2007). In IFT, users forage for information using their metaphorical sense of smell which helps guides them through patchy areas of their environment. This preliminary research leverages IFT to build two versions of a clickstream model of information foraging that uses clickstream data to explain goal achievement. The goal being examined is the purchase of a product or submission of a contact form at long tail websites (i.e., sites with limited traffic). The first version of the model uses session-level panel data to examine across-website goal-seeking browsing patterns. Page-level data is used in the second version of the model to reason about browsing patterns within a website. The hypotheses and their related measures are presented for each version of the model

Pleiotropic Effects of DDT Resistance on Male Size and Behaviour

Understanding the evolution and spread of insecticide resistance requires knowing the relative fitness of resistant organisms. In the absence of insecticides, resistance is predicted to be costly. The Drosophila melanogaster DDT resistance allele (DDT-R) is associated with a male mating cost. This could be because resistant males are generally smaller, but DDT-R may also alter courtship behaviours. Here we tested for body size and courtship effects of DDT-R on mating success in competitive and non-competitive mating trials respectively. We also assessed relative aggression in resistant and susceptible males because aggression can also influence mating success. While the effect of DDT-R on male size partly contributed to reduced mating success, resistant males also had lower rates of courtship and were less aggressive than susceptible males. These differences contribute to the observed DDT-R mating costs. Additionally, these pleiotropic effects of DDT-R are consistent with the history and spread of resistance alleles in nature

Intestinal Tumorigenesis Is Not Affected by Progesterone Signaling in Rodent Models

Clinical data suggest that progestins have chemopreventive properties in the development of colorectal cancer. We set out to examine a potential protective effect of progestins and progesterone signaling on colon cancer development. In normal and neoplastic intestinal tissue, we found that the progesterone receptor (PR) is not expressed. Expression was confined to sporadic mesenchymal cells. To analyze the influence of systemic progesterone receptor signaling, we crossed mice that lacked the progesterone receptor (PRKO) to the ApcMin/+ mouse, a model for spontaneous intestinal polyposis. PRKO-ApcMin/+mice exhibited no change in polyp number, size or localization compared to ApcMin/+. To examine effects of progestins on the intestinal epithelium that are independent of the PR, we treated mice with MPA. We found no effects of either progesterone or MPA on gross intestinal morphology or epithelial proliferation. Also, in rats treated with MPA, injection with the carcinogen azoxymethane did not result in a difference in the number or size of aberrant crypt foci, a surrogate end-point for adenoma development. We conclude that expression of the progesterone receptor is limited to cells in the intestinal mesenchyme. We did not observe any effect of progesterone receptor signaling or of progestin treatment in rodent models of intestinal tumorigenesis

Self-control interventions for children under age 10 for improving self-control and delinquency and problem behaviors

Self-control improvement programs are intended to serve many purposes, most notably improving self-control. Yet, interventions such as these often aim to reduce delinquency and problem behaviors. However, there is currently no summary statement available regarding whether or not these programs are effective in improving self-control and reducing delinquency and problem behaviors. The main objective of this review is to assess the available research evidence on the effect of self-control improvement programs on self-control and delinquency and problem behaviors. In addition to investigating the overall effect of early selfcontrol improvement programs, this review will examine, to the extent possible, the context in which these programs may be most successful. The studies included in this systematic review indicate that self-control improvement programs are an effective intervention for improving self-control and reducing delinquency and problem behaviors, and that the effect of these programs appears to be rather robust across various weighting procedures, and across context, outcome source, and based on both published and unpublished data

Polymorphic population of Oncorhynchus nerka at Babine Lake, B.C. involving anadromous (sockeye) and non-anadromous (kokanee) forms

The sockeye and kokanee are, respectively, the anadromous and non-anadromous forms of the Pacific salmon species, Oncorhynchus nerka. Both life history types inhabit Babine Lake, British Columbia, a tributary of the Skeena River system. The purpose of this study was to examine the ecology, morphology and behaviour of sockeye and kokanee in the hope that an understanding of these would provide clues to the genetic relationship of the two forms in Babine Lake. A comparison of the life histories of sockeye and kokanee at Babine Lake revealed a.number of differences. At the time they undertake their seaward migration (usually during the spring of their second summer) sockeye smolts have a mean length greater than that of same-age kokanee. Smolts have an approximately equal sex ratio while, among kokanee, males usually exceed females in abundance. As a result of better growth conditions in the ocean, sockeye, at maturity, are much larger than kokanee. Related to this basic difference in size are differences in fecundity, egg size and testis weight in each of which sockeye exceed kokanee. Laboratory experiments revealed that, regardless of the male parent, progeny of the larger sockeye eggs had an initial size advantage over the progeny of kokanee eggs which they maintained through July of their first year. There was no conclusive evidence of differential mortality to hybrid embryos. There are differences between sockeye and kokanee in two meristic characters: number of lateral line scales and number of vertebrae.In both instances, mean values for sockeye exceed those for kokanee. It is suggested that this difference may not be genetic in origin but rather the result of differences in the amount of yolk incorporated in eggs. The two forms did not differ in gill-raker count. Electrophoretic examination of haemoglobins and muscle myogens revealed no differences between Babine Lake sockeye and kokanee. A detailed examination of the reproductive behaviour of sockeye and kokanee revealed that they spawn sympatrically in a group of streams known as the "early streams." These are small streams which experience considerable fluctuation in water levels and spawning suitability from year to year. Sockeye and kokanee in the early streams overlap almost completely in their spawning season and in their distribution on the spawning grounds. Evidence is presented that hybridization does occur under natural conditions. A study of the homing performance of mature sockeye and kokanee displaced from early streams indicates that they are less likely to home than are sockeye displaced from Pinkut Creek, a large, stable stream in the same area. It is suggested that a reduced homing tendency might be an adaptation to the unstable nature of the early streams. Fish homing to an early stream to which access is blocked, either by low water or by an obstruction, have the alternative of entering other, nearby streams of similar type. The hypothesis which most readily encompasses the available information is that the sockeye and kokanee in the early streams at Babine Lake are part of the same polymorphic population. This polymorphism is presumably maintained by a balance of contending advantages and disadvantages. Kokanee suffer the major disadvantage of smaller size resulting in reduced fecundity, smaller egg size and, probably, reduced spawning success. However, it would appear that they persist in the early streams because they are able to utilize spawning grounds which are unavailable to sockeye under low water conditions. The existence of such a sockeye/kokanee polymorphism and the reduced tendency to home are both thought to be genetically regulated adaptations which enable the early stream populations of O. nerka to maximize their utilization of the available spawning grounds in. the face of extreme fluctuations in the suitability of spawning streams. The hereditary mechanism which would regulate such a sockeye/kokanee polymorphism is not known. Possibly a super-gene is involved. Whatever the mechanism, it would appear that factors other than genotype can influence the tendency to smolt: females are more likely to smolt than males; larger and/or faster growing fish are more likely to smolt than smaller, slower growing fish; immature fish are more likely to smolt than those in which maturation processes have already begun. The applicability of the polymorphism hypothesis to sockeye and kokanee populations in other areas is discussed.Science, Faculty ofZoology, Department ofGraduat

Goal Attainment On Long Tail Web Sites: An Information Foraging Approach

This dissertation sought to explain goal achievement at limited traffic “long tail” Web sites using Information Foraging Theory (IFT). The central thesis of IFT is that individuals are driven by a metaphorical sense of smell that guides them through patches of information in their environment. An information patch is an area of the search environment with similar information. Information scent is the driving force behind why a person makes a navigational selection amongst a group of competing options. As foragers are assumed to be rational, scent is a mechanism by which to reduce search costs by increasing the accuracy on which option leads to the information of value. IFT was originally developed to be used in a “production rule” environment, where a user would perform an action when the conditions of a rule were met. However, the use of IFT in clickstream research required conceptualizing the ideas of information scent and patches in a non-production rule environment. To meet such an end this dissertation asked three research questions regarding (1) how to learn information patches, (2) how to learn trails of scent, and finally (3) how to combine both concepts to create a Clickstream Model of Information Foraging (CMIF). The learning of patches and trails were accomplished by using contrast sets, which distinguished between individuals who achieved a goal or not. A user- and site-centric version of the CMIF, which extended and operationalized IFT, presented and evaluated hypotheses. The user-centric version had four hypotheses and examined product purchasing behavior from panel data, whereas the site-centric version had nine hypotheses and predicted contact form submission using data from a Web hosting company. In general, the results show that patches and trails exist on several Web sites, and the majority of hypotheses were supported in each version of the CMIF. This dissertation contributed to the literature by providing a theoretically-grounded model which tested and extended IFT; introducing a methodology for learning patches and trails; detailing a methodology for preprocessing clickstream data for long tail Web sites; and focusing on traditionally under-studied long tail Web sites

Growth and morphometry of the pygmy whitefish (Prosopium coulteri) in British Columbia

The present study is, in part, a description of meristic variation in the pygmy whitefish, Prosopium coulteri, of British Columbia fish with those of other areas. The species was shown to be highly variable meristically both within and between populations. There are indications in some characters of a north-south cline of meristic counts. One character (gill raker counts) seems to form a V-shaped curve of variation. The major part of the study is a comparison of the growth and relative growth of fish from four British Columbia lakes. The two "giant" forms from MacLure and McLeese Lakes are more like one another in relative growth than like either of the two dwarf forms inhabiting Cluculz Lake or Tacheeda Lake. The possible relationship between growth, form and environment is discussed.Science, Faculty ofZoology, Department ofGraduat