Numerical study of ultrasound induced non-linear shape and size bubble oscillations in viscoelastic media

The theoretical study of forced bubble oscillations is motivated by the importance of cavitation bubbles and oscillating encapsulated microbubbles (i.e. contrast agents) in medical sciences. In more details,theoretical studies on bubble dynamics addressing the sound-bubble interaction phenomenon provide the basis for understanding the dynamics of contrast agent microbubbles used in medical diagnosis and of non-linearly oscillating cavitation bubbles in the case of high-intensity ultrasound therapy. Moreover, the inclusion of viscoelasticity is of vital importance for an accurate theoretical analysis since most biological tissues and fluids exhibit non-Newtonian behavior.

Ethnic Print Media in the multicultural nation of Canada: A case study of the black newspaper in Montreal

This article explores the social and cultural roles of ethnic print media in the country within the prism of Canada's multicultural policy. Specifically, the article examines how the ethnic groups are framed in the mainstream national media in Canada and then examines how these ethnic media are [re]constructing their own identities in contrast to their framed identities in the mainstream national print media such as the Globe and Mail, National Post and Toronto Sun. In exploring the overall socio-political impacts of these ethnic print media on the social fabrics and cultural identity in Canadian society, Montreal Community Contact, an ethnic newspaper of the black community in Montreal, is used as a case study. Copyright © 2006 SAGE Publications.

A study of the micro-mechanics of granular media

The development of more realistic constitutive models for granular media, such as sand, requires ingredients which take into account the internal micro-mechanical response to deformation. Unfortunately, at present, very little is known about these mechanisms and therefore it is instructive to find out more about the internal nature of granular samples by conducting suitable tests. In contrast to physical testing the method of investigation used in this study employs the Distinct Element Method. This is a computer based, iterative, time-dependent technique that allows the deformation of granular assemblies to be numerically simulated. By making assumptions regarding contact stiffnesses each individual contact force can be measured and by resolution particle centroid forces can be calculated. Then by dividing particle forces by their respective mass, particle centroid velocities and displacements are obtained by numerical integration. The Distinct Element Method is incorporated into a computer program 'Ball'. This program is effectively a numerical apparatus which forms a logical housing for this method and allows data input and output, and also provides testing control. By using this numerical apparatus tests have been carried out on disc assemblies and many new interesting observations regarding the micromechanical behaviour are revealed. In order to relate the observed microscopic mechanisms of deformation to the flow of the granular system two separate approaches have been used. Firstly a constitutive model has been developed which describes the yield function, flow rule and translation rule for regular assemblies of spheres and discs when subjected to coaxial deformation. Secondly statistical analyses have been carried out using data which was extracted from the simulation tests. These analyses define and quantify granular structure and then show how the force and velocity distributions use the structure to produce the corresponding stress and strain-rate tensors.

The effect of intraocular scattered light on the contrast sensitivity function

Intraocular light scatter is high in certain subject groups eg the elderly, due to increased optical media turbidity, which scatters and attenuates light travelling towards the retina. This causes reduced retinal contrast especially in the presence of glare light. Such subjects have depressed Contrast Sensitivity Functions (CSF). Currently available clinical tests do not effectively reflect this visual disability. Intraocular light scatter may be quantified by measuring the CSF with and without glare light and calculating Light Scatter Factors (LSF). To record the CSF on clinically available equipment (Nicolet CS2000), several psychophysical measurement techniques were investigated, and the 60 sec Method of Increasing Contrast was selected as the most appropriate. It was hypothesised that intraocular light scatter due to particles of different dimensions could be identified by glare sources at wide (30°) and narrow (3.5°) angles. CSFs andLSFs were determined for: (i) Subjects in young, intermediate and old age groups. (ii) Subjects during recovery from large amounts of induced corneal oedema. (iii) A clinical sample of contact lens (CL) wearers with a group of matched controls. The CSF was attenuated at all measured spatial frequencies with the intermediate and old group compared to the young group. High LSF values were found only in the old group (over 60 years). It was concluded that CSF attenuation in the intermediate group was due to reduced pupil size, media absorption and/or neural factors. In the old group, the additional factor was high intraocular light scatter levels of lenticular origin. The rate of reduction of the LSF for the 3.5° glare angle was steeper than that for the 30° angle, following induced corneal oedema. This supported the hypothesis, as it was anticipated that epithelial oedema would recover more rapidly than stromal oedema. CSFs and LSFs were markedly abnormal in the CL wearers. The analytical details and the value of these investigative techniques in contact lens research are discussed.

"Gene-fouled or gene-improved?" – Media framing of GM crops and food in Hungary

This paper presents results from a research which analyzed the reporting on genetically modified crops and food in the Hungarian tabloids and political papers with the highest circulation from 1 May 2007 to 31 October 2009. Both quantitative and qualitative media analysis was conducted. It was found that in contrast to some Western countries the issue had low salience in the investigated period; it featured especially marginally in the tabloids. Two distinct valenced frames could be differentiated: a dominant ANTI-GM (Threat) frame – which was particularly frequent compared to what has been found for some other countries, and a minority PRO-GM (Advancement and Benefits) frame. Despite a range of similarities with what had been reported by previous research from some other countries, argumentation on the GMO topic in the Hungarian press had several distinct characteristics, one of which was the relative prominence of economic arguments against the technology.

Social media to support collaboration in the product life cycle of SMEs

Abstract : The use of social media tools to support small and medium-sized enterprises (SME) to support their business activities throughout the product life cycle (PLC) phases represents an interesting opportunity. SMEs operate in very competitive environments, and face significant challenges primarily caused by their size disadvantage. By nature, social media tools and platforms can enable them to overcome some of these challenges, as they are often very inexpensive, familiar and easy to use, allowing them to reach large audiences they would not be able to reach with traditional and expensive marketing initiatives. To provide solutions to this problem, this research identified three main objectives. The first objective was to draw a picture of the existing academic literature on the use of social media tools in the PLC context to better understand how these tools were studied and used in businesses, and for what purpose. Second, this research aimed at understanding how SMEs actually use social media tools to support their different business activities to identify the gap between academic research and actual business practices. Finally, based on the findings highlighted from the previous objectives, this research aimed at developing theory on this topic by proposing a conceptual framework of customer engagement enabled by social media. The conceptual framework aimed at answering general questions that emerged from the initial two objectives: Why do some SMEs use social media to support customer engagement, while others do not? Why do firms use different social media tools to support their customer engagement initiatives? Why does the scope of customer engagement initiatives (i.e., across different PLC phases) vary between SMEs? What are the potential outcomes of conducting customer engagement initiatives for the organizing firms? In order to achieve these research objectives, the methodology employed for this research is threefold. First, a systematic literature review was performed in order to properly understand how the use of social media tools in the PLC context had been studied. The final results consisted of 78 academic articles which were analyzed based on their bibliometric information and their content. Second, in order to draw the contrast between the academic publications and managerial reality of SMEs, six semi-structured interviews were conducted to understand how these firms actually use social media to support different activities in each of the PLC phases. Third, five additional semi-structured interviews were performed to gather a deeper understanding of this phenomenon and generate theory to support the proposed conceptual framework. The conceptual framework focuses on the degree of customer engagement, which is comprised of the scope (PLC phases) of customer engagement and the technology (social media tools) employed to support these initiatives. Two sets of antecedents were examined, firm motivators and firm impediments, as they could both potentially affect the scope and the social media tools used to support customer engagement initiatives. Finally, potential customer engagement outcomes for SMEs developing these initiatives were also examined. The semi-structured interviews lasted approximately 25-35 minutes, and were performed using an interview grid consisting of 24 open-ended questions. The interview grid was developed based on the findings of the systematic literature review, and this qualitative approach allowed for a rich understanding of the interviewed SMEs’ use of social media tools to support and engage customers in their different PLC activities. The main results highlighted by this project demonstrate that this field is relatively recent and sees constant increase in research interest since 2008. However, most of the academic research focuses on the use of social media tools to support innovation activities during the new product development process, while the interviewed firms almost exclusively used the tools to engage customers in the later phases of the PLC, primarily for promotion, customer service support, and business development activities. Interestingly, the interviewed firms highlighted several benefits of using social media tools to engage customers, some of which could help them overcome certain size disadvantages previously mentioned. These firms are in need of further guidelines to properly implement such initiatives and reap the expected benefits. Results suggest that SMEs are far behind both large companies and academic research in their use of social media to engage customers in different business activities. The proposed conceptual framework serves as a great tool to better understand their reality and eventually better support them in their social media and customer engagement efforts. However, this framework needs to be further developed and improved. This research project provides a 360-degree view of the phenomenon of the use of social media to support customer engagement for SMEs, by providing both a thorough systematic review of the academic research and an understanding of the managerial reality of SMEs behind this phenomenon. From this analysis, a conceptual framework is then proposed and serves as a stepping stone for future researchers who are interested in developing theory in this field.

No right to sext? A critical examination of media and legal debates about teenage girls' sexual agency in the digital age

Advances in digital photography and distribution technologies enable many people to produce and distribute images of their sex acts. When teenagers do this, the photos and videos they create can be legally classified as child pornography since the law makes no exception for youth who create sexually explicit images of themselves. The dominant discussions about teenage girls producing sexually explicit media (including sexting) are profoundly unproductive: (1) they blame teenage girls for creating private images that another person later maliciously distributed and (2) they fail to respect—or even discuss—teenagers’ rights to freedom of expression. Cell phones and the internet make producing and distributing images extremely easy, which provide widely accessible venues for both consensual sexual expression between partners and for sexual harassment. Dominant understandings view sexting as a troubling teenage trend created through the combination of camera phones and adolescent hormones and impulsivity, but this view often conflates consensual sexting between partners with the malicious distribution of a person’s private image as essentially equivalent behaviors. In this project, I ask: What is the role of assumptions about teen girls’ sexual agency in these problematic understandings of sexting that blame victims and deny teenagers’ rights? In contrast to the popular media panic about online predators and the familiar accusation that youth are wasting their leisure time by using digital media, some people champion the internet as a democratic space that offers young people the opportunity to explore identities and develop social and communication skills. Yet, when teen girls’ sexuality enters this conversation, all this debate and discussion narrows to a problematic consensus. The optimists about adolescents and technology fall silent, and the argument that media production is inherently empowering for girls does not seem to apply to a girl who produces a sexually explicit image of herself. Instead, feminist, popular, and legal commentaries assert that she is necessarily a victim: of a “sexualized” mass media, pressure from her male peers, digital technology, her brain structures or hormones, or her own low self-esteem and misplaced desire for attention. Why and how are teenage girls’ sexual choices produced as evidence of their failure or success in achieving Western liberal ideals of self-esteem, resistance, and agency? Since mass media and policy reactions to sexting have so far been overwhelmingly sexist and counter-productive, it is crucial to interrogate the concepts and assumptions that characterize mainstream understandings of sexting. I argue that the common sense that is co-produced by law and mass media underlies the problematic legal and policy responses to sexting. Analyzing a range of nonfiction texts including newspaper articles, talk shows, press releases, public service announcements, websites, legislative debates, and legal documents, I investigate gendered, racialized, age-based, and technologically determinist common sense assumptions about teenage girls’ sexual agency. I examine the consensus and continuities that exist between news, nonfiction mass media, policy, institutions, and law, and describe the limits of their debates. I find that this early 21st century post-feminist girl-power moment not only demands that girls live up to gendered sexual ideals but also insists that actively choosing to follow these norms is the only way to exercise sexual agency. This is the first study to date examining the relationship of conventional wisdom about digital media and teenage girls’ sexuality to both policy and mass media.

Sexuality in the media and emotional well-being among lesbian, gay, & bisexual adolescents

LGB teens’ feelings, desires, and physical attractions run contrary to the heteronormative standards of American society. As such, LGB youth often experience feelings of sadness and dejection that can lead to depression and suicidal tendencies (Russell & Joyner, 2001). Evaluating the factors that could possibly influence the emotional well-being of LGB youth would be an important undertaking given the hindrances LGB adolescents face during sexual socialization. The purpose of this dissertation was to study the portrayal of sexuality in media popular with LGB adolescents and to assess the relationship between media exposure and emotional well-being among LGB teens. In particular, this dissertation distinguished between mainstream media and gay- and lesbian-oriented (GLO) media. GLO media were defined as any media outlet specifically designed, produced, and marketed for gay and lesbian audiences. Two studies were conducted to serve as the initial investigation in a program of research that will be designed to better understand the role of media in the lives of LGB individuals. The first study of this dissertation was a content analysis of the television programs, films, songs, and magazines most popular with LGB teens as determined by self-reports of media consumption in a survey of media use. A total of 96 media vehicles composed the content analysis sample, including 48 television programs, 22 films, 25 musical artists, and 6 magazines. Using a coding scheme that was adapted from previous media sex research, Study 1 measured the frequency of sexual instances as well as the type, nature, and source characteristics for each sexual instance. Results of the content analysis suggest that heterosexuality reigns supreme in mainstream media. When LGB sexuality is depicted in mainstream media, it is often sanitized. LGB sexual talk is rarely sexual; rather it is primarily about the social or cultural components of being lesbian, gay, or bisexual. LGB sexual behavior is also rare in mainstream media, which tend to depict LGB individuals as non-sexually as possible. LGB sexuality in mainstream media exists, but is more about proclaiming LGB identity than actually living it. GLO media depicted LGB sexuality more frequently than mainstream media did. GLO media often depict LGB sexuality in a more realistic manner. LGB sexual talk is about LGB identity, as well as the relational and sexual aspects of being a sexual minority. LGB sexual behavior is commonplace in GLO media, depicting LGB individuals as sexual beings. LGB sexuality in GLO media is prevalent and relatively authentic. The second study was a survey that assessed the relationship between media exposure (both mainstream media and GLO media) and LGB teens’ emotional well-being, considering self-discrepancy as an important mediating variable in that relationship. Study 2 also considered age, sex, and sexual identity commitment as possible moderating variables in the relationship between media exposure and emotional well-being. In Study 2, emotional well-being was defined as lower levels of dejection-related emotions. LGB adolescents (N = 573) completed a questionnaire that was used to investigate the relationships between media exposure and emotional well-being. Results of the survey indicated that mainstream media exposure was not significantly associated with dejection-related emotions. In contrast, GLO media exposure was negatively related to feelings of dejection even when controlling for age, sex, race, perceived social support, school climate, religiosity, geographical location, sexuality of peers, and motivation for viewing LGB inclusive media content. Neither age nor sex moderated the relationships between media exposure variables and dejection, but sexual identity commitment did act as a moderator in the relationship between GLO media exposure and dejection. The negative relationship between GLO media exposure and dejection was stronger for participants lower in sexual identity commitment than for participants higher in sexual identity commitment. In addition, the magnitude of discrepancies between the actual self and the ideal self mediated the relationship between GLO media exposure and dejection for LGB adolescents low in sexual identity commitment. However, self-discrepancy did not mediate the relationship between GLO media exposure and dejection for LGB teens highly committed to their sexual identities. Results of both the content analysis and the survey are discussed in terms of implications for theory and method. Practical implications of this dissertation’s findings are also discussed, as well as directions for future research.

A second order control-volume finite-element least-squares strategy for simulating diffusion in strongly anisotropic media

An unstructured mesh �nite volume discretisation method for simulating di�usion in anisotropic media in two-dimensional space is discussed. This technique is considered as an extension of the fully implicit hybrid control-volume �nite-element method and it retains the local continuity of the ux at the control volume faces. A least squares function recon- struction technique together with a new ux decomposition strategy is used to obtain an accurate ux approximation at the control volume face, ensuring that the overall accuracy of the spatial discretisation maintains second order. This paper highlights that the new technique coincides with the traditional shape function technique when the correction term is neglected and that it signi�cantly increases the accuracy of the previous linear scheme on coarse meshes when applied to media that exhibit very strong to extreme anisotropy ratios. It is concluded that the method can be used on both regular and irregular meshes, and appears independent of the mesh quality.