233 research outputs found

    Investigation of angiogenic effects of bioactive borate glass microfibers and beads in a rodent model

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    The primary objective of this research project was to evaluate the effects of three different compositions of bioactive glass microfibers (45S5, 13-93B3, and 13-93B3Cu) and bioactive glass beads (13-93, 13-93B3, and 13-93B3Cu) on angiogenesis in subcutaneous tissue in the SKH1 \u27hairless\u27 mouse. Microvascular responses to the bioactive glass implants were investigated via three experimental approaches: noninvasive vital imaging of microvasculature in dorsal skin windows; quantitative histomorphometry of microvascular densities; and quantitative PCR measurements of mRNA expression of pro-angiogenic cytokines VEGF and FGF-2. The live imaging of dorsal skin window preparations in the hairless SKH1 showed the formation of a halo-like structure infused with vessels in soft tissue surrounding borate-based 13-93B3 and 13-93B3Cu glass beads two weeks after implantation. This response was not observed around silicate-based 13-93 glass beads. Quantitative histomorphometry of tissue implanted with 45S5, 13-93B3, and 13-93B3Cu glass microfiber plugs revealed microvascular densities that were 1.6-, 2.3-, and 2.7-fold higher, respectively compared to the sham control tissues whereas the 13-93, 13-93B3, and 13-93B3Cu glass beads produced a 1.3-, 1.6-, and 2.5-fold increase, respectively, compared to the sham control. Quantitative PCR measurements indicate a marginally significant increase in expression of VEGF mRNA in skin tissues with 13-93B3Cu. This latter outcome supports the project hypothesis that 13-93B3Cu glass induces VEGF expression followed by neovascularization, a key process of wound healing. --Abstract, page iv

    Contemporary Rhetoric, Ethics, and Human Rights Advocacy (abstract)

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    This paper will discuss how rhetorical analysis might interpret current ethics conversation related to governance and re-position some of its touchstone rationales. Specifically, efforts in this paper will apply the ideas of preeminent rhetorician Gerald Hauser (the current editor of Philosophy and Rhetoric) about human rights discourses and of a reticulate (variegated) public sphere to intersection of governance and human rights advocacy. Specifically, our paper will examine the rhetoric of various “exemplars” who advocate for causes and actions pertaining to human rights in particular contexts. In particular, we will incorporate case studies reviewing the public actions of the Russian rock group “Pussy Riot” and the Dutch ultra-right parliamentarian Geert Wilders as rhetors whose discourses serve as grist for comparative analysis. Our comparison of these rhetors is premised on the assertion that concern for how particular individuals advocate for human rights causes –as well as how antagonists obstruct such initiatives –adds significant value to understanding the successes and failures of human rights efforts in particular cultural and national contexts. On one hand, we can grasp how specific international organizations and actors function to develop norms (for example, the rights of the child) and how rights are subsequently articulated in universal declarations and formal codes. But on the other, it becomes apparent that the actual meaning of those rights mutate when “accepted” within particular cultures. A final section of our paper will discuss how contemporary rhetorical analysis might inform the ethics of human rights discourse and advocacy in praxis. In this regard, Gerald Hauser elaborates upon thick and thin moral vernaculars in the context of human rights advocacy; specifically, he takes exponents of thin regime principles (e.g. those codified in the Universal Declaration of Human Rights) to task, emphasizing the importance of discourse that is constructed in the context of rights and “moral empowerment.

    Design of Test Support Hardware for Advanced Space Suits

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    As a member of the Space Suit Assembly Development Engineering Team, I designed and built test equipment systems to support the development of the next generation of advanced space suits. During space suit testing it is critical to supply the subject with two functions: (1) cooling to remove metabolic heat, and (2) breathing air to pressurize the space suit. The objective of my first project was to design, build, and certify an improved Space Suit Cooling System for manned testing in a 1G environment. This design had to be portable and supply a minimum cooling rate of 2500 BTU/hr. The Space Suit Cooling System is a robust, portable system that supports very high metabolic rates. It has a highly adjustable cool rate and is equipped with digital instrumentation to monitor the flowrate and critical temperatures. It can supply a variable water temperature down to 34 deg., and it can generate a maximum water flowrate of 2.5 LPM. My next project was to design and build a Breathing Air System that was capable of supply facility air to subjects wearing the Z2 space suit. The system intakes 150 PSIG breathing air and regulates it to two operating pressures: 4.3 and 8.3 PSIG. It can also provide structural capabilities at 1.5x operating pressure: 6.6 and 13.2 PSIG, respectively. It has instrumentation to monitor flowrate, as well as inlet and outlet pressures. The system has a series of relief valves to fully protect itself in case of regulator failure. Both projects followed a similar design methodology. The first task was to perform research on existing concepts to develop a sufficient background knowledge. Then mathematical models were developed to size components and simulate system performance. Next, mechanical and electrical schematics were generated and presented at Design Reviews. After the systems were approved by the suit team, all the hardware components were specified and procured. The systems were then packaged, fabricated, and thoroughly tested. The next step was to certify the equipment for manned used, which included generating a Hazard Analysis and giving a presentation to the Test Readiness Review Board. Both of these test support systems will perform critical roles in the development of nextgeneration space suits. They will used on a regular basis to test the NASA's new Z2 Space Suit. The Space Suit Cooling System is now the primary cooling system for all advanced suit tests

    Catches per unit of effort of bigeye tuna: a new analysis with regression trees and simulated annealing

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    ENGLISH: We analyzed catches per unit of effort (CPUE) from the Japanese longline fishery for bigeye tuna (Thunnus obesus) in the central and eastern Pacific Ocean (EPO) with regression tree methods. Regression trees have not previously been used to estimate time series of abundance indices fronl CPUE data. The "optimally sized" tree had 139 parameters; year, month, latitude, and longitude interacted to affect bigeye CPUE. The trend in tree-based abundance indices for the EPO was similar to trends estimated from a generalized linear model and fronl an empirical model that combines oceanographic data with information on the distribution of fish relative to environmental conditions. The regression tree was more parsimonious and would be easier to implement than the other two nl0dels, but the tree provided no information about the nlechanisms that caused bigeye CPUEs to vary in time and space. Bigeye CPUEs increased sharply during the mid-1980's and were more variable at the northern and southern edges of the fishing grounds. Both of these results can be explained by changes in actual abundance and changes in catchability. Results from a regression tree that was fitted to a subset of the data indicated that, in the EPO, bigeye are about equally catchable with regular and deep longlines. This is not consistent with observations that bigeye are more abundant at depth and indicates that classification by gear type (regular or deep longline) may not provide a good measure of capture depth. Asimulated annealing algorithm was used to summarize the tree-based results by partitioning the fishing grounds into regions where trends in bigeye CPUE were similar. Simulated annealing can be useful for designing spatial strata in future sampling programs. SPANISH: Analizamos la captura por unidad de esfuerzo (CPUE) de la pesquería palangrera japonesa de atún patudo (Thunnus obesus) en el Océano Pacifico oriental (OPO) y central con métodos de árbol de regresión. Hasta ahora no se han usado árboles de regresión para estimar series de tiempo de índices de abundancia a partir de datos de CPUE. EI árbol de "tamaño optimo" tuvo 139 parámetros; ano, mes, latitud, y longitud interactuaron para afectar la CPUE de patudo. La tendencia en los índices de abundancia basados en árboles para el OPO fue similar a las tendencias estimadas con un modelo lineal generalizado y con un modelo empírico que combina datos oceanográficos con información sobre la distribución de los peces en relación con las condiciones ambientales. EI árbol de regresión fue mas parsimonioso y seria mas fácil de utilizar que los dos otros modelos, pero no proporciono información sobre los mecanismos que causaron que las CPUE de patudo valiaran en el tiempo y en el espacio. Las CPUE de patudo aumentaron notablemente a mediados de los anos 80 y fueron mas variables en los extremos norte y sur de la zona de pesca. Estos dos resultados pueden ser explicados por cambios en la abundancia real y cambios en la capturabilidad. Los resultados de un arbal de regresión ajustado a un subconjunto de los datos indican que, en el OPO, el patudo es igualmente capturable con palangres regulares y profundos. Esto no es consistente con observaciones de que el patudo abunda mas a profundidad e indica que clasificación por tipo de arte (palangre regular 0 profundo) podría no ser una buena medida de la profundidad de captura. Se uso un algoritmo de templado simulado para resumir los resultados basados en el árbol clasificando las zonas de pesca en zonas con tendencias similares en la CPUE de patudo. El templado simulado podría ser útil para diseñar estratos espaciales en programas futuros de muestreo. (PDF contains 45 pages.

    Angiogenic Effect of Bioactive Borate Glass Microfibers and Beads in the Hairless Mouse

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    The purpose of this project was to investigate the angiogenic mechanism of bioactive borate glass for soft tissue repair in a \u27hairless\u27 SKH1 mouse model. Subcutaneous microvascular responses to bioactive glass microfibers (45S5, 13-93B3, and 13-93B3Cu) and bioactive glass beads (13-93, 13-93B3, and 13-93B3Cu) were assessed via: noninvasive imaging of skin microvasculature; histomorphometry of microvascular densities; and quantitative PCR measurements of mRNA expression of VEGF and FGF-2 cytokines. Live imaging via dorsal skin windows showed the formation at two weeks of a halo-like structure infused with microvessels surrounding implanted borate-based 13-93B3 and 13-93B3Cu glass beads, a response not observed with silicate-based 13-93 glass beads. Quantitative histomorphometry of tissues implanted with plugs of 45S5, 13-93B3, and 13-93B3Cu glass microfibers revealed microvascular densities that were 1.6-, 2.3-, and 2.7-times higher, respectively, than the sham control values whereas 13-93, 13-93B3, and 13-93B3Cu glass beads caused the microvascular density to increase 1.3-, 1.6-, and 2.5-fold, respectively, relative to sham controls. Quantitative PCR measurements indicate a marginally significant increased expression of VEGF mRNA in tissues with 13-93B3Cu glass beads, an outcome that supported the hypothesis that copper-doped borate glass could promote VEGF expression followed by angiogenesis for enhanced wound healing

    Creating Honeypots to Prevent Online Child Exploitation

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    Honeypots have been a key tool in controlling and understanding digital crime for several decades. The tool has traditionally been deployed against actors who are attempting to hack into systems or as a discovery mechanism for new forms of malware. This paper presents a novel approach to using a honeypot architecture in conjunction with social networks to respond to non-technical digital crimes. The tool is presented within the context of Child Exploitation Material (CEM), and to support the goal of taking an educative approach to Internet users who are developing an interest in this material. The architecture that is presented in the paper includes multiple layers, including recruitment, obfuscation, and education. The approach does not aim to collect data to support punitive action, but to educate users, increasing their knowledge and awareness of the negative impacts of such material

    Unsupervised authorship analysis of phishing webpages

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    Authorship analysis on phishing websites enables the investigation of phishing attacks, beyond basic analysis. In authorship analysis, salient features from documents are used to determine properties about the author, such as which of a set of candidate authors wrote a given document. In unsupervised authorship analysis, the aim is to group documents such that all documents by one author are grouped together. Applying this to cyber-attacks shows the size and scope of attacks from specific groups. This in turn allows investigators to focus their attention on specific attacking groups rather than trying to profile multiple independent attackers. In this paper, we analyse phishing websites using the current state of the art unsupervised authorship analysis method, called NUANCE. The results indicate that the application produces clusters which correlate strongly to authorship, evaluated using expert knowledge and external information as well as showing an improvement over a previous approach with known flaws. © 2012 IEEE

    Authorship attribution for Twitter in 140 characters or less

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    Authorship attribution is a growing field, moving from beginnings in linguistics to recent advances in text mining. Through this change came an increase in the capability of authorship attribution methods both in their accuracy and the ability to consider more difficult problems. Research into authorship attribution in the 19th century considered it difficult to determine the authorship of a document of fewer than 1000 words. By the 1990s this values had decreased to less than 500 words and in the early 21 st century it was considered possible to determine the authorship of a document in 250 words. The need for this ever decreasing limit is exemplified by the trend towards many shorter communications rather than fewer longer communications, such as the move from traditional multi-page handwritten letters to shorter, more focused emails. This trend has also been shown in online crime, where many attacks such as phishing or bullying are performed using very concise language. Cybercrime messages have long been hosted on Internet Relay Chats (IRCs) which have allowed members to hide behind screen names and connect anonymously. More recently, Twitter and other short message based web services have been used as a hosting ground for online crimes. This paper presents some evaluations of current techniques and identifies some new preprocessing methods that can be used to enable authorship to be determined at rates significantly better than chance for documents of 140 characters or less, a format popularised by the micro-blogging website Twitter1. We show that the SCAP methodology performs extremely well on twitter messages and even with restrictions on the types of information allowed, such as the recipient of directed messages, still perform significantly higher than chance. Further to this, we show that 120 tweets per user is an important threshold, at which point adding more tweets per user gives a small but non-significant increase in accuracy. © 2010 IEEE

    How to implement online warnings to prevent the use of child sexual abuse material

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    Online CSAM offending is a challenge for law enforcement, policymakers and child welfare organisations alike. The use of online warning messages to prevent or deter an individual when they actively search for CSAM is gaining traction as a response to some types of CSAM offending. Yet, to date, the technical question of how warning messages can be implemented, and who can implement them, has been largely unexplored. To address this, we use a case study to analyse the actions individuals and organisations within the technology, government, nongovernment and private sectors could take to implement warning messages. We find that, from a technical perspective, there is considerable opportunity to implement warning messages, although further research into efficacy and cost is needed
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