1,697 research outputs found
Information is Not Lost in the Evaporation of 2-dimensional Black Holes
We analyze Hawking evaporation of the Callen-Giddings-Harvey-Strominger
(CGHS) black holes from a quantum geometry perspective and show that
information is not lost, primarily because the quantum space-time is
sufficiently larger than the classical. Using suitable approximations to
extract physics from quantum space-times we establish that: i)future null
infinity of the quantum space-time is sufficiently long for the the past vacuum
to evolve to a pure state in the future; ii) this state has a finite norm in
the future Fock space; and iii) all the information comes out at future
infinity; there are no remnants.Comment: 4 pages, 2 figure
In or Out? Experiential Learning and Three Consequences of Communicating Group Identity
Group identity is intimately tied with self identity. Yet, people often understand their identity as individual without appreciation for the role others play in their identity. Based on social identity theory this article highlights the role that group identity plays in self identity and explores three consequences of this association. Case studies present first-hand experience with the consequences of communicating group identity. These case studies also demonstrate the value of a specific class project undertaken to provide students with a meaningful understanding of these issues
PERSPECTIVES ON ENVIRONMENTAL MANAGEMENT SYSTEM REQUIREMENTS
This report offers perspectives on effective environmental management procedures gained through field experience with the Peace Corps in Peru and with the United Nations Office for Project Services (UNOPS) in Copenhagen, Denmark. The work in Peru focused on case studies of rural water supply management within the context of local legislation and development strategies and environmental management principles. The objective of this study was to lay out a framework for future development workers and governmental agencies aiming to improve the administration and operation of rural water system. UNOPS on the other hand, as the operational arm of the UN for the provision of infrastructure services, had piloted an Environmental Management System in compliance with ISO14001 standards in 2013. The work there involved identifying gaps in the system requirements and providing support to field operations in over 40 countries. The work with UNOPS was informed by the environmental management work started in Peru. The lessons learned on legal requirements and compliance and identifying the relevant supporting institutional stakeholders proved essential in supporting country offices in the implementation of the UNOPS Environmental Management System.
The first component is a literature review of work done by the Canadian governmental organization World University Service of Canada (WUSC) in Ancash, Peru. The outcomes of this intervention were published in a Peruvian Water and Sanitation periodical. This case study was selected because this same organization, in the years 1990-1995, worked on developing rural water access in the province of Palpa, another region of Peru and the site of volunteer service with the Peace Corps from 2010-2014. This field research allowed for an ethnographic study of the region 20 years after the initial scope of the intervention highlighting lessons learned and making recommendations for improvements. This study looks at ten rural water supply systems using Qualitative Comparative Analysis methods to identify causal relationships between the organizational management of these communities. Having identified the key activities required for the effective management of rural water supplies and the relevant stakeholders, it was possible to present the local government with a Rural Water Security Plan, outlining the course of action for improved water services. The organizational framework for the administration, operation, and maintenance of these water systems is then broken down according to Engineering Project Organization principles, taking into account the peculiarities of intermittent water supply management in order to determine the most sustainable course of action for improving rural water system management.
Finally, a summary is provided of the work accomplished with the Sustainable Infrastructure Practice Group of UNOPS, under the Health, Safety, and Environmental Management Program. Working within the structure of the ISO standards, the focus is on a risk-based approach to project planning and emergency preparedness with attention to detail regarding the maintenance of records, legal compliance, and the monitoring of program performance
HIV Risk Behaviors, Previous HIV Testing and Positivity among Hispanic Women Tested for HIV in Florida, 2012
The prevalence of female adults and adolescents living with diagnosed HIV infection continues to rise. Latina women in the United States (US) are not only disproportionately affected by human immunodeficiency virus (HIV) infection, but also underutilize HIV prevention services, such as HIV testing. Data are limited on the differences in HIV risk among Latinas by country of birth, and opportunities still exist to prevent transmission of HIV and reduce HIV-related disparities. This dissertation describes the risk behaviors, testing behaviors, and test results among women tested for HIV at public sites in Florida. Additionally, it compares these characteristics by HIV testing site type among pregnant women. Multivariable logistic regression was used to estimate the adjusted odds ratios (AOR) and associated 95% confidence intervals for the outcome variables of risk behaviors, previous testing, and positive HIV test results.
Of the total 209,954 records, 184,037 were from women not currently pregnant, of which 87,569 (45.6%) were among non-Hispanic Blacks (NHBs), 47,926 (26.0%) non-Hispanic Whites (NHWs), and 41,117 (22.3%) Latinas. Women who reported previous HIV testing had decreased odds of being Latina compared to NHW women (AOR 0.90; 95% confidence interval [CI] 0.87, 0.94), and testing event results indicate that foreign-born Latina women were significantly less likely to report partner risk (AOR 0.42; 95% CI: 0.40-0.54) than US-born Latina women. Of the 24,863 records of pregnant women, 10,199 (41.1%) were among Latinas, 6,796 (27.4%) were among NHB, and 6,631 (26.7%) were among NHW. The testing records indicated that Latina and NHB women had decreased odds of reporting partner risk than NHW women (Latina: AOR 0.20; 95% CI: 0.14-0.28; and NHB: AOR 0.14; 95% CI: 0.10-0.21), and records of women tested in prisons/jails had higher odds of reporting previous HIV testing compared to prenatal care sites (AOR 1.86; 95% CI: 1.03-3.39).
Reported risk behaviors varied by race/ethnicity and Latina country of origin. Knowledge of these differences can enhance current testing and prevention strategies for women, and aid in targeting HIV prevention messaging, program decision-making, and allocation of resources, corresponding to the central approach of High Impact Prevention and the National HIV/AIDS Strategy
Virtual Reality Interfaces for Product Design: Finding User Interface solutions for design creation within Virtual Reality
The focus of Virtual Reality has gone from research to widespread adoption in entertainment and practical directions, like automotive design and architectural visualization. With that, we have to take into consideration the best way to give in-experience control to the user and the interaction within the interface.
Recent studies explore the ergonomic considerations and zones of content for VR interfaces. But Virtual Reality interaction design has a long way to go and nowadays is done mainly like a projection of 2D screens, with planar interfaces in the 3D space, almost ignoring the immersive potential of the Virtual Reality medium (Alger 2015; Google Developers 2017).
Designers that work with 3D objects might find it difficult to make design decisions and validate their concepts based on context and empathy. To help with this, they often prototype, which can take a great deal of time and effort. Virtual reality can be a tool that improves the process and gives the designer an unconstrained and flexible canvas.
By reimagining interactions for Virtual Reality, this thesis aims to create interface tools that help designers explore shape and manipulate their designs
Las estrellas de Hollywood como prescriptores en el spot publicitario: un activo para las marcas y anunciantes
It is true that the prescriber is characterized by recommending and speak well about the qualities and benefits of a brand, product or service. However, given the postmodern society in which we live we conceive that advertising with film star uses a more indirect narrative concept, to the point that almost seems no prescription. Whereupon, the article, based on an analysis of a sample of 41 spots argues that reputation, transtextuality and mythic power of the Hollywood star are the reasons leading brands to engage actors in Hollywood and roll spots that waive the requirement for another sustained direct what is called in Narratology enunciadoras or discursive instances where the author / s (for us the actor), the implied author (for us the star) and the character of the story, involved convey the idea of the advertiser. This is explained further how the famous benefits of brand recognition and brand awareness and image of the prescriber. Notoriety, transtextualidad and power become legendary for the brand in what Aaker (2002) active calls. This will force us to determine: the reputation of the actor on par with the brand, features and roles of characters and the image of the star. What happens to these three levels favors announced the sale of the object and at the same time, a confluence between these narrative elements and visibility, identity and brand values occurs.Es cierto que el prescriptor se caracteriza por recomendar y hablar bien sobre las cualidades y beneficios de una marca, producto o servicio. Sin embargo, dada la sociedad postmoderna en la que vivimos, concebimos, que la publicidad con estrella cinematográfica se sirve de un concepto narrativo más indirecto, al punto que casi parece que no hay prescripción. Con lo cual, el artículo, a partir del análisis de una muestra de 41 spots sostiene, que la notoriedad, la transtextualidad y el poder mítico de la estrella hollywoodense son las razones que llevan a las marcas a contratar actores de Hollywood y rodar spots que renuncian a la prescripción directa por otra sostenida sobre lo que en Narratología se llama, instancias enunciadoras o discursivas, donde el autor/es (para nosotros el actor), el autor implícito (para nosotros la estrella) y el personaje de la historia, intervienen para transmitir la idea del anunciante. Se trata de explicar, además, cómo el famoso se beneficia del reconocimiento de las marcas y las marcas de la notoriedad e imagen del prescriptor. Notoriedad, transtextualidad y poder mítico se convierten para la marca en lo que Aaker (2002) llama activos. Ello nos obligará a determinar: la notoriedad del actor en equivalencia con la marca, rasgos y roles del personajes y la imagen de la estrella. Lo que sucede a estos tres niveles favorece la venta del objeto anunciado y, al mismo tiempo, se produce una confluencia entre estos elementos narrativos y la notoriedad, identidad y valores de marca
The performance of 2D and 3D tsunami evacuation maps: A case study for Seaside, Oregon
Tsunami evacuation maps are intended to inform the public about the geographic extent of the hazard and where to evacuate, but these maps can be difficult to interpret for people unfamiliar with cartographic semiology. This study focuses on the performance of tsunami evacuation maps and how the tsunami hazard is represented cartographically, as at-risk communities must be able to act quickly, and effectively understand tsunami maps to remain aware of the hazard and adequately evacuate. This study investigated the use of static three-dimensional (3D) perspective maps and travel time to safety representation (shown using point markers and choropleth symbology), as alternative ways to help mitigate tsunami disaster. The performance of, and preference for, static 3D tsunami evacuation maps were compared to conventional two-dimensional (2D) evacuation maps using a user survey and a set of test maps for the area of Seaside, Oregon. Each participant was given either a 2D or 3D map showing travel times as either point markers or choropleth symbology, and asked to complete a series of tasks concerning terrain and positional judgment, and evacuation travel time estimation. Participants were also shown all four maps and asked to determine which map was best for completing the tasks mentioned above. There were 84 survey respondents, and the results indicated that the 3D maps were preferred, overall. 3D maps performed best for judging terrain but showed no difference in performance when judging position. There was no difference in performance between 3D maps using choropleth symbology and 2D maps using point markers when estimating travel times. The results indicate that 3D maps perform the same or better than 2D maps and are preferred, suggesting the use of 3D maps for tsunami evacuation planning and education
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Role of Aurora B-mediated phosphorylation during mitosis and interphase
Accurate chromosome segregation requires a spindle apparatus composed of microtubules that arise from the spindle to attach to the kinetochore, a protein complex assembled at the centromere of each chromosome. Failure to segregate chromosomes accurately may lead to lethal early developmental defects and tumorigenesis. To achieve proper kinetochore binding to microtubules, mammalian cells have evolved elaborate mechanisms to correct attachment errors and stabilize correct ones. Current models suggest that tension between kinetochore pairs (inter-kinetochore stretch) and tension at the kinetochore (intra-kinetochore stretch) produces a spatial separation of Aurora B kinase from kinetochore-associated and microtubule-binding substrates, subsequently reducing their phosphorylations and increasing their microtubule affinity. However, the tension-based models do not explain how the initial microtubule binding at unattached kinetochores occurs, where there is no tension and kinetochore-associated substrates are highly phosphorylated and, hence unable to bind to microtubules. Therefore, there must be a mechanism that explains how the phosphorylation of kinetochore substrates by Aurora B is reduced in the absence of tension.
In the first part of this thesis, I examine the structural features of the coiled-coil domain of the kinetochore-associated kinesin motor protein, CENP-E. Using Single-Molecule High-Resolution Colocalization (SHREC) microscopy analysis of kinetochore-associated CENP-E, I show that CENP-E undergoes structural rearrangements prior to and after tension generation at the kinetochore. Chemical inhibition of the motor motility or genetic perturbations of the coiled-coil domain of CENP-E increases Aurora B-mediated Ndc80 phosphorylation in a tension-independent manner. Importantly, metaphase chromosome misalignment caused by inhibition of CENP-E can be rescued by chemical inhibition of Aurora B kinase. Therefore, CENP-E regulates the initial kinetochore binding to microtubules and the stabilization of kinetochore-microtubule attachments.
Formin-dependent actin assembly is known to play a role in multiple processes, including cytokinesis, filopodia formation, cell polarity, and cell adhesion. Thus, formin malfunction is directly linked to various pathologies, including defects in cell migration and tumor suppression. Although the role of formins in actin polymerization has been well described, the mechanistic processes that regulate the actin assembly function of formins remain poorly understood, especially the interplay among the various sub-families of formins and how they are spatiotemporally regulated.
In the second part of this thesis, I show that Aurora B-mediated phosphorylation of the formin, mDia3 regulates actin assembly. Previous studies identified two Aurora B phosphorylation sites in the FH2 domain of mDia3. To this end, phosphomimetic and non-phosphorylatable mutants of a constitutively active form of mDia3 were designed to test whether phosphorylation by Aurora B regulates actin assembly. Using an in vitro actin polymerization kinetic assay and expression of fluorescently-tagged constitutively active mDia3 in cells, I show that phosphorylation of mDia3 by Aurora B induces the actin assembly function of mDia3. Furthermore, using a phospho-specific antibody, I show that mDia3 is phosphorylated by Aurora B. Live-cell analysis shows that perturbations of these phosphorylation sites affect cell migration and cell spreading. Therefore, I illustrate a novel regulatory mechanism for the actin assembly function of mDia3 that is dependent on Aurora B kinase activity
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