Diffusion in spatially and temporarily inhomogeneous media: Effects of turbulent mixing

We consider diffusion of a passive substance C in a phase-separating nonmiscible binary alloy under turbulent mixing. The substance is assumed to have different diffusion coefficients in the pure phases A and B, leading to a spatially and temporarily dependent diffusion ¿coefficient¿ in the diffusion equation plus convective term. In this paper we consider especially the effects of a turbulent flow field coupled to both the Cahn-Hilliard type evolution equation of the medium and the diffusion equation (both, therefore, supplemented by a convective term). It is shown that the formerly observed prolonged anomalous diffusion [H. Lehr, F. Sagués, and J.M. Sancho, Phys. Rev. E 54, 5028 (1996)] is no longer seen if a flow of sufficient intensity is supplied.

Diffusion in spatially and temporarily inhomogeneous media: Effects of turbulent mixing

We consider diffusion of a passive substance C in a phase-separating nonmiscible binary alloy under turbulent mixing. The substance is assumed to have different diffusion coefficients in the pure phases A and B, leading to a spatially and temporarily dependent diffusion ¿coefficient¿ in the diffusion equation plus convective term. In this paper we consider especially the effects of a turbulent flow field coupled to both the Cahn-Hilliard type evolution equation of the medium and the diffusion equation (both, therefore, supplemented by a convective term). It is shown that the formerly observed prolonged anomalous diffusion [H. Lehr, F. Sagués, and J.M. Sancho, Phys. Rev. E 54, 5028 (1996)] is no longer seen if a flow of sufficient intensity is supplied.

Flooded with Information from Social Media: Effects of Disaster Information Source and Visuals on Viewers' Cognitive, Affective, and Behavioral Responses

While a variety of crisis types loom as real risks for organizations and communities, and the media landscape continues to evolve, research is needed to help explain and predict how people respond to various kinds of crisis and disaster information. For example, despite the rising prevalence of digital and mobile media centered on still and moving visuals, and stark increases in Americans’ use of visual-based platforms for seeking and sharing disaster information, relatively little is known about how the presence or absence of disaster visuals online might prompt or deter resilience-related feelings, thoughts, and/or behaviors. Yet, with such insights, governmental and other organizational entities as well as communities themselves may best help individuals and communities prepare for, cope with, and recover from adverse events. Thus, this work uses the theoretical lens of the social-mediated crisis communication model (SMCC) coupled with the limited capacity model of motivated mediated message processing (LC4MP) to explore effects of disaster information source and visuals on viewers’ resilience-related responses to an extreme flooding scenario. Results from two experiments are reported. First a preliminary 2 (disaster information source: organization/US National Weather Service vs. news media/USA Today) x 2 (disaster visuals: no visual podcast vs. moving visual video) factorial between-subjects online experiment with a convenience sample of university students probes effects of crisis source and visuals on a variety of cognitive, affective, and behavioral outcomes. A second between-subjects online experiment manipulating still and moving visual pace in online videos (no visual vs. still, slow-pace visual vs. still, medium-pace visual vs. still, fast-pace visual vs. moving, slow-pace visual vs. moving, medium-pace visual vs. moving, fast-pace visual) with a convenience sample recruited from Amazon’s Mechanical Turk (mTurk) similarly probes a variety of potentially resilience-related cognitive, affective, and behavioral outcomes. The role of biological sex as a quasi-experimental variable is also investigated in both studies. Various implications for community resilience and recommendations for risk and disaster communicators are explored. Implications for theory building and future research are also examined. Resulting modifications of the SMCC model (i.e., removing “message strategy” and adding the new category of “message content elements” under organizational considerations) are proposed.

Optimal beam forming for laser beam propagation through random media

Focusing optical beams on a target through random propagation media is very important in many applications such as free space optical communica- tions and laser weapons. Random media effects such as beam spread and scintillation can degrade the optical system's performance severely. Compensation schemes are needed in these applications to overcome these random media effcts. In this research, we investigated the optimal beams for two different optimization criteria: one is to maximize the concentrated received intensity and the other is to minimize the scintillation index at the target plane. In the study of the optimal beam to maximize the weighted integrated intensity, we derive a similarity relationship between pupil-plane phase screen and extended Huygens-Fresnel model, and demonstrate the limited utility of maximizing the average integrated intensity. In the study ofthe optimal beam to minimize the scintillation index, we derive the first- and second-order moments for the integrated intensity of multiple coherent modes. Hermite-Gaussian and Laguerre-Gaussian modes are used as the coherent modes to synthesize an optimal partially coherent beam. The optimal beams demonstrate evident reduction of scintillation index, and prove to be insensitive to the aperture averaging effect.

Customer response to media in marketing promotion: print versus online

Il lavoro di tesi, che si compone di tre articoli di ricerca, analizza, nel contesto della marketing promotion, la risposta del consumatore ai media in termini di ricordo, intenzione di acquisto, comportamento di acquisto e preferenza per il medium. Il lavoro, in particolare, mette a confronto due tipologie di media, carta e online, nell’ambito della price e loyalty promotion, utilizzando due disegni di ricerca sperimentali ed uno correlazionale. I risultati del lavoro mostrano che la risposta del consumatore alla comunicazione promozionale e ai media è eterogenea: segmenti di clienti diversi rispondono in maniera differente sia alla comunicazione promozionale che a carta e digitale. Online e carta hanno in media la stessa efficacia sui comportamenti di acquisto dei clienti, ma differiscono rispetto all’effetto su ricordo e atteggiamento e rispetto alla preferenza per il medium espressa dalla clientela. Lo spostamento delle risorse di marketing dalla carta al digitale permetterebbe quindi di ridurre i costi mantenendo lo stesso livello di efficacia. Inoltre, il presente lavoro mostra come sia possibile aumentare la risposta dei consumatori ai media attraverso un approccio di segmentazione della clientela.

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.

Surface diffusion and adsorption of hydrocarbons in activated carbon

Adsorption and diffusion in a porous media were studied theoretically and experimentally with a differential transient permeation method. The porous medium is allowed to equilibrate at some specified loading, and then the time trajectory of the permeation process is followed after a small difference between the pressures at the end faces of the porous medium is introduced at time t = 0 +. Such a trajectory us. time would contain adsorption and diffusion characteristics of the system. By studying this for various surface loadings, pore and surface diffusions can be fully characterized. Mathematical modeling of transient permeation is detailed for pure gases or vapors diffusion and adsorption in porous media. Effects of nonlinearity of adsorption isotherm, pressure, temperature and heat effects were considered in the model. Experimental data of diffusion and adsorption of propane, n-butane and n-hexane in activated carbon at different temperatures and loadings show the potential of this method as a useful tool to study adsorption kinetics in porous media. Validity of the model is best tested against the transient data where the kinetics curves exhibit sigmoidal shape, which is a result of the diffusion and adsorption rate during the initial stage of permeation.

Corruption in building the image of politics in television news broadcasts

This work analyses the political news of eight Spanish television channels in order to see what image is built of politics, and particularly how the news of corruption affects the image of politics in Spanish news broadcasts. Different cases of corruption such as Gürtel, Palma Arena and those associated with judge Baltasar Garzón in his final stage in office, occupy part of the study. A new methodology is therefore proposed that enables the quality of the political information emitted from inside and outside the political content of the news programmes to be observed. Particular attention is paid to the news broadcasts of Televisión Española and Cuatro as those which offer a more balanced view of politics, and channels such as La Sexta, which give priority to a narrative construction of politics in the news programmes around causes of corruption.

Quand la politique et la génétique se rencontrent : comment le public interprète-t-il la recherche?

L’objectif général de cette thèse de doctorat est de mieux comprendre comment le public interprète les nouvelles scientifiques portant sur la génétique humaine, plus précisément les nouvelles portant sur la génétique des comportements et celles portant sur la génétique des groupes raciaux. L’ouvrage prend la forme d’une thèse par article. Le Chapitre 1 introduit le lecteur aux buts et aux pratiques de la vulgarisation scientifique, présente un sommaire de la recherche sur les effets des médias, résume les principaux travaux produits par le champ de la génopolitique, et définit la structure des croyances du public à l’égard de l’influence de la génétique sur les traits humains. Le Chapitre 2 présente les fondements de la méthode expérimentale, il en explique les atouts et il offre des exemples de différents types de devis expérimentaux utilisés en science politique. Toutes les recherches produites dans cette thèse reposent au moins en partie sur cette méthode. Le Chapitre 3 présente les résultats d’une expérience de sondage qui vise à mesurer l’effet de la lecture d’une nouvelle à propos de la recherche en génétique des comportements sur des participants. L’étude démontre que le public interprète la nouvelle avec maladresse et tend à généraliser l’influence de la génétique à d’autres traits humains qui n’y sont pas mentionnés. J’avance l’hypothèse qu’un raccourci psychologique amplement documenté puisse expliquer cette réaction : l’heuristique de l’ancrage et de l’ajustement. Le Chapitre 4 présente lui aussi les résultats d’une expérience de sondage. L’étude consiste à manipuler certaines informations du contenu d’une nouvelle sur la génopolitique de manière à vérifier si certains éléments sont particulièrement susceptibles de mener à la généralisation hâtive mise en évidence dans le Chapitre 3. Les analyses suggèrent que cette généralisation est amplifiée lorsque la nouvelle présente de hauts niveaux d’héritabilité tirés d’études de jumeaux, ainsi que lorsqu’elle présente des travaux de génétique des populations visant à étudier l’origine des différences géographiques. Ce chapitre présente des recommandations à l’égard des journalistes scientifiques. Le Chapitre 5 s’intéresse à un aspect différent de la génétique humaine : celui de la génétique des races. L’objectif de cette recherche est de comprendre comment le public réagit aux travaux qui invalident l’idée selon laquelle les humains sont divisés en différentes races génétiquement distinctes. Les analyses de données transversales ainsi que les résultats d’une expérience de sondage convergent et indiquent que les conservateurs et les libéraux réagissent de manière diamétralement opposée à cette information. D’un côté, les libéraux acceptent le constat scientifique et réduisent leur impression que la génétique explique en partie les inégalités sociales; de l’autre, les conservateurs rejettent l’argument avec une intensité si forte que le rôle qu’ils attribuent aux différences génétiques s’en voit bonifié. Ces résultats sont interprétés à partir de la théorie du raisonnement motivé. Enfin, le Chapitre 6 résume les principaux constats, met en évidence les contributions que ma thèse apporte à la science politique et à la communication scientifique, et présente quelques pistes pour la recherche future.

The Agendas of The Stream

The new tech has introduced the traits of the hypermedia, interactivity and convergence in the journalism field. Moreover, it has involved the emergence of new media and changes in the informative contents. In 2006 Al Jazeera in English was created for covering the underreported regions, inasmuch as new media arise, new contents do so, thus, the research examines the agendas of The Stream, the TV show from Al Jazeera that relies heavily on social networks.

Children's Perceptions of Male and Female Athletes as Presented in Sports Illustrated for Kids

Despite gains made by Title IX in the past 36 years, including increased female participation in high school and collegiate sport, there is evidence that gender equity in sport is not fully achieved. Researchers target the media because they tend to shape social values and disseminate information to the masses (Kane, 1978, in Fink & Kensicki, 2002). As sports become more pervasive, framing theory has become particularly relevant. The purpose of this study is to build on the Hardin et al. (2002) study by examining the relationship among media sports coverage, gender equity in sport and the perceptions young sports fans begin to form about gender and sport based on media consumption. The researcher hypothesized that since women face discrimination in sport starting from the time that they choose to participate, children will perceive male athletes and their sports as more legitimate. Additionally, the media play a major role in shaping the views of audiences, so the way that they represent male and female athletes, including juxtaposing them, may have an impact on children. The researcher conducted a content analysis of 24 Sports Illustrated for Kids issues from 1996 to 1999 and 24 issues from 2006 to 2007. The researcher analyzed the content of photographs (N=3219) and of headlines (N=762) by using the definitions determined by Hardin et al. (2002). We found that there is a disproportionate amount of coverage devoted to male athletes and that the discrepancy between media representation between men and women in sport has grown since the mid-1990s. This study also includes a focus group conducted with three children from a community swimming program in a northeastern town and found that those children were acutely aware of the differences between men and women in sport based on the discussion. The researcher does not attempt to find a causal relationship between these children’s perceptions and the way media represents them, but rather uses the focus group to complement the content analysis. As children become sports consumers in later life, future research exploring the relationship between children’s perceptions and the media’s representations need to be done before causality and the significance of media effects are determined.

Mejora de la seguridad de las presas de escollera frente a percolación accidental mediante protecciones tipo repié

Esta tesis doctoral es el fruto de un trabajo de investigación cuyo objetivo principal es definir criterios de diseño de protecciones en forma de repié en presas de materiales sueltos cuyo espaldón de aguas abajo esté formado por escollera. La protección propuesta consiste en un relleno de material granular situado sobre el pie de aguas abajo de la presa y formado a su vez por una escollera con características diferenciadas respecto de la escollera que integra el espaldón de la presa. La función de esta protección es evitar que se produzcan deslizamientos en masa cuando una cantidad de agua anormalmente elevada circula accidentalmente por el espaldón de aguas abajo de la presa por distintos motivos como pueden ser el vertido por coronación de la presa o la pérdida de estanqueidad del elemento impermeable o del cimiento. Según los datos de la International Commission on Large Dams (ICOLD 1995) el 70% de las causas de rotura o avería grave en presas de materiales sueltos en el mundo están dentro de las que se han indicado con anterioridad. Esta circulación accidental de agua a través del espaldón de escollera, típicamente turbulenta, se ha denominado en esta tesis percolación (“through flow”, en inglés) para diferenciarla del término filtración, habitualmente utilizada para el flujo laminar a través de un material fino. El fenómeno físico que origina la rotura de presas de materiales sueltos sometidas a percolación accidental es complejo, entrando en juego diversidad de parámetros, muchas veces no deterministas, y con acoplamiento entre procesos, tanto de filtración como de arrastre y deslizamiento. En esta tesis se han realizado diferentes estudios experimentales y numéricos con objeto de analizar el efecto sobre el nivel de protección frente al deslizamiento en masa que producen los principales parámetros geométricos que definen el repié: la anchura de la berma, el talud exterior y su altura máxima desde la base. También se han realizado estudios sobre factores con gran influencia en el fenómeno de la percolación como son la anisotropía del material y el incremento de los caudales unitarios en el pie de presa debidos a la forma de la cerrada. A partir de los resultados obtenidos en las distintas campañas de modelación física y numérica se han obtenido conclusiones respecto a la efectividad de este tipo de protección para evitar parcial o totalmente los daños provocados por percolación accidental en presas de escollera. El resultado final de la tesis es un procedimiento de diseño para este tipo de protecciones. Con objeto de completar los criterios de dimensionamiento, teniendo en cuenta los mecanismos de rotura por erosión interna y arrastre, se han incluido dentro del procedimiento recomendaciones adicionales basadas en investigaciones existentes en la bibliografía técnica. Finalmente, se han sugerido posibles líneas de investigación futuras para ampliar el conocimiento de fenómenos complejos que influyen en el comportamiento de este tipo de protección como son el efecto de escala, la anisotropía de la escollera, las leyes de resistencia que rigen la filtración turbulenta a través de medios granulares, los efectos de cimentaciones poco competentes o la propia caracterización de las propiedades de la escollera de presas. This thesis is the result of a research project that had the main objective of defining criteria to design rockfill toe protections for dams with a highly‐permeable downstream shoulder. The proposed protection consists of a rockfill toe berm situated downstream from the dam with specific characteristics with respect to the rockfill that integrates the shoulder of the main dam. The function of these protections is to prevent mass slides due to an abnormally high water flow circulation through the dam shoulder. This accidental seepage flow may be caused by such reasons as overtopping or the loss of sealing at the impervious element of the dam or its foundation. According to data from the International Commission on Large Dams (ICOLD 1995), 70% of the causes of failure or serious damage in embankment dams in the world are within that described previously. This accidental seepage of water through the rockfill shoulder, typically turbulent, is usually called through‐flow. The physical phenomenon which causes the breakage of the rockfill shoulder during such through‐flow processes is complex, involving diversity of parameters (often not deterministic) and coupling among processes, not only seepage but also internal erosion, drag or mass slide. In this thesis, numerical and experimental research is conducted in order to analyze the effects of the main parameters that define the toe protection, i.e. the toe crest length, its slope and maximum height. Additional studies on significant factors which influence the seepage, such as the anisotropy of the material and the increase of the unit flows at the dam toe due to the valley shape are also performed. In addition, conclusions regarding the effectiveness of this type of protection are obtained based on the results of physical and numerical models. The main result of the thesis is a design procedure for this type of protection to avoid mass sliding. In order to complete the design criteria, additional recommendations about internal and external erosion based on the state of the art are included. Finally, new lines of research are suggested for the future to expand the level of knowledge of the complex phenomena that influence the behavior of this type of protection, such as the effects of scale, rockfill anisotropy, non‐linear seepage laws in turbulent seepage through granular media, effects of erodible foundations, or new procedures to characterize the properties of dam rockfill as a construction material.

Random locomotion and chemotaxis of human blood polymorphonuclear leukocytes (PMN) in the presence of EDTA: PMN in close quarters require neither leukocyte integrins nor external divalent cations

Divalent cations are thought essential for motile function of leukocytes in general, and for the function of critical adhesion molecules in particular. In the current study, under direct microscopic observation with concomitant time-lapse video recording, we examined the effects of 10 mM EDTA on locomotion of human blood polymorphonuclear leukocytes (PMN). In very thin slide preparations, EDTA did not impair either random locomotion or chemotaxis; motile behavior appeared to benefit from the close approximation of slide and coverslip (“chimneying”). In preparations twice as thick, PMN in EDTA first exhibited active deformability with little or no displacement, then rounded up and became motionless. However, on creation of a chemotactic gradient, the same cells were able to orient and make their way to the target, often, however, losing momentarily their purchase on the substrate. In either of these preparations without EDTA, specific antibodies to β2 integrins did not prevent random locomotion or chemotaxis, even when we added antibodies to β1 and αvβ3 integrins and to integrin-associated protein, and none of these antibodies added anything to the effects of EDTA. In the more turbulent environment of even more media, effects of anti-β2 integrins became evident: PMN still could locomote but adhered to substrate largely by their uropods and by uropod-associated filaments. We relate these findings to the reported independence from integrins of PMN in certain experimental and disease states. Moreover, we suggest that PMN locomotion in close quarters is not only integrin-independent, but independent of external divalent cations as well.

Infants, interfaces, and intermediation: digital parenting and the production of 'iPad baby' videos on YouTube

We investigate the ways young children’s use of mobile touchscreen interfaces is both understood and shaped by parents through the production of YouTube videos and discussions in associated comment threads. This analysis expands on, and departs from, theories of parental mediation, which have traditionally been framed through a media effects approach in analyzing how parents regulate their children’s use of broadcast media, such as television, within family life. We move beyond the limitations of an effects framing through more culturally and materially oriented theoretical lenses of mediation, considering the role mobile interfaces now play in the lives of infants through analysis of the ways parents intermediate between domestic spaces and networked publics. We propose the concept of intermediation, which builds on insights from critical interface studies as well as cultural industries literature to help account for these expanded aspects of digital parenting. Here, parents are not simply moderating children’s media use within the home, but instead operating as an intermediary in contributing to online representations and discourses of children’s digital culture. This intermediary role of parents engages with ideological tensions in locating notions of “naturalness:” the iPad’s gestural interface or the child’s digital dexterity.