Numerical investigation of all-optical add-drop multiplexing for spectrally overlapping OFDM signals

We propose a novel architecture for all-optical add-drop multiplexing of OFDM signals. Sub-channel extraction is achieved by means of waveform replication and coherent subtraction from the OFDM super-channel. Numerical simulations have been carried out to benchmark the performance of the architecture against critical design parameters.

Experimental demonstration of an all-optical interferometric drop, add, and extract multiplexer for OFDM super-channel

The experimental implementation of an all-optical node able of routing a channel contained in an all-optical OFDM super-channel is presented. The extract function is performed through channel selection, reshaping and interferometric suppression.

Class placement and academic and behavioral variables as predictors of graduation for students with disabilities

Dropout rates impacting students with high-incidence disabilities in American schools remain staggering (Bost, 2006; Hehir, 2005). Of this group, students with Emotional Behavioral Disorders (EBD) are at greatest risk. Despite the mandated national propagation of inclusion, students with EBD remain the least included and the least successful when included (Bost). Accordingly, this study investigated the potential significance of inclusive settings and other school-related variables within the context of promoting the graduation potential of students with Specific Learning Disabilities (SLD) or EBD. This mixed-methods study investigated specified school-related variables as likely dropout predictors, as well as the existence of first-order interactions among some of the variables. In addition, it portrayed the perspectives of students with SLD or EBD on the school-related variables that promote graduation. Accordingly, the sample was limited to students with SLD or EBD who had graduated or were close to graduation. For the quantitative component the numerical data were analyzed using linear and logistic regressions. For the qualitative component guided student interviews were conducted. Both strands were subsequently analyzed using Ridenour and Newman’s (2008) model where the quantitative hypotheses are tested and are later built-upon by the related qualitative meta-themes. Results indicated that a successful academic history, or obtaining passing grades was the only significant predictor of graduation potential when statistically controlling all the other variables. While at a marginal significance, results also yielded that students with SLD or EBD in inclusive settings experienced better academic results and behavioral outcomes than those in self-contained settings. Specifically, students with SLD or EBD in inclusive settings were found to be more likely to obtain passing grades and less likely to be suspended from school. Generally, the meta-themes yielded during the student interviews corroborated these findings as well as provided extensive insights on how students with disabilities view school within the context of promoting graduation. Based on the results yielded, provided the necessary academic accommodations and adaptations are in place, along with an effective behavioral program, inclusive settings can be utilized as drop-out prevention tools in special education.

Navigating racial boundaries: The one-drop rule and mixed-race Jamaicans in South Florida

Like many West Indians, mixed-race Jamaican immigrants enter the United States with fluid notions about race and racial identifications that reflect socio-political events in their home country and that conflict with the more rigid constructions of race they encounter in the U.S. This dissertation explores the experiences of racially mixed Jamaicans in South Florida and the impact of those experiences on their racial self-characterizations through the boundary-work theoretical framework. Specifically, the study examines the impact of participants’ exposure to the one-drop rule in the U.S., by which racial identification has been historically determined by the existence or non-existence of black forebears. Employing qualitative data collected through both focus group and face-to-face semi-structured interviews, the study analyzes mixed-race Jamaicans’ encounters in the U.S. with racial boundaries, and the boundary-work that reinforces them, as well their response to these encounters. Through their stories, the dissertation examines participants’ efforts to navigate racial boundaries through choices of various racial identifications. Further, it discusses the ways in which structural forces and individual agency have interacted in the formation of these identifications. The study finds that in spite of participants’ expressed preference for non-racialism, and despite their objections to rigid racial categories, in seeking to carve out alternative identities, they are participating in the boundary-making of which they are so critical.^

Events Impacting Lodging Capital Flow

By reviewing events in the last quarter of the 20th century that have impacted the amount and type of lodging industry financing, the author analyzes these historical trends and major events to alert lodging industry investors, lenders, legislators, and hotel operators when similar events emerge in the future

Women-led community development organizations (CDOs) in Miami-Dade County: A model of community development efforts impacting the economic security of women

Recent studies on the economic status of women in Miami-Dade County (MDC) reveal an alarming rate of economic insecurity and significant obstacles for women to achieve economic security. Consistent barriers to women's economic security affect not only the health and wellbeing of women and their families, but also economic prospects for the community. A key study reveals in Miami-Dade County, "Thirty-nine percent of single female-headed families with at least one child are living at or below the federal poverty level" and "over half of working women do not earn adequate income to cover their basic necessities" (Brion 2009, 1). Moreover, conventional measures of poverty do not adequately capture women's struggles to support themselves and their families, nor do they document the numbers of women seeking basic self-sufficiency. Even though there is lack of accurate data on women in the county, which is a critical problem, there is also a dearth of social science research on existing efforts to enhance women's economic security in Miami-Dade County. My research contributes to closing the information gap by examining the characteristics and strategies of women-led community development organizations (CDOs) in MDC, working to address women's economic insecurity. The research is informed by a framework developed by Marilyn Gittell, who pioneered an approach to study women-led CDOs in the United States. On the basis of research in nine U.S. cities, she concluded that women-led groups increased community participation and "by creating community networks and civic action, they represent a model for community development efforts" (Gittell, et al. 2000, 123). My study documents the strategies and networks of women-led CDOs in MDC that prioritize women's economic security. Their strategies are especially important during these times of economic recession and government reductions in funding towards social services. The focus of the research is women-led CDOs that work to improve social services access, economic opportunity, civic participation and capacity, and women's rights. Although many women-led CDOs prioritize building social infrastructures that promote change, inequalities in economic and political status for women without economic security remain a challenge (Young 2004). My research supports previous studies by Gittell, et al., finding that women-led CDOs in Miami-Dade County have key characteristics of a model of community development efforts that use networking and collaboration to strengthen their broad, integrated approach. The resulting community partnerships, coupled with participation by constituents in the development process, build a foundation to influence policy decisions for social change. In addition, my findings show that women-led CDOs in Miami-Dade County have a major focus on alleviating poverty and economic insecurity, particularly that of women. Finally, it was found that a majority of the five organizations network transnationally, using lessons learned to inform their work of expanding the agency of their constituents and placing the economic empowerment of women as central in the process of family and community development.

Class Placement and Academic and Behavioral Variables as Predictors of Graduation for Students with Disabilities

Dropout rates impacting students with high-incidence disabilities in American schools remain staggering (Bost, 2006; Hehir, 2005). Of this group, students with Emotional Behavioral Disorders (EBD) are at greatest risk. Despite the mandated national propagation of inclusion, students with EBD remain the least included and the least successful when included (Bost). Accordingly, this study investigated the potential significance of inclusive settings and other school-related variables within the context of promoting the graduation potential of students with Specific Learning Disabilities (SLD) or EBD. This mixed-methods study investigated specified school-related variables as likely dropout predictors, as well as the existence of first-order interactions among some of the variables. In addition, it portrayed the perspectives of students with SLD or EBD on the school-related variables that promote graduation. Accordingly, the sample was limited to students with SLD or EBD who had graduated or were close to graduation. For the quantitative component the numerical data were analyzed using linear and logistic regressions. For the qualitative component guided student interviews were conducted. Both strands were subsequently analyzed using Ridenour and Newman’s (2008) model where the quantitative hypotheses are tested and are later built-upon by the related qualitative meta-themes. Results indicated that a successful academic history, or obtaining passing grades was the only significant predictor of graduation potential when statistically controlling all the other variables. While at a marginal significance, results also yielded that students with SLD or EBD in inclusive settings experienced better academic results and behavioral outcomes than those in self-contained settings. Specifically, students with SLD or EBD in inclusive settings were found to be more likely to obtain passing grades and less likely to be suspended from school. Generally, the meta-themes yielded during the student interviews corroborated these findings as well as provided extensive insights on how students with disabilities view school within the context of promoting graduation. Based on the results yielded, provided the necessary academic accommodations and adaptations are in place, along with an effective behavioral program, inclusive settings can be utilized as drop-out prevention tools in special education.

Dynamic method of stiffness identification in impacting systems for percussive drilling applications

Peer reviewed

Factors Impacting Grandparent and Grand Child Communication Across Sex- Related Topics in Kenya

Background: Although many studies have investigated sexual communication between parents and children in Kenya, none have focused singularly on grandparent and grandchild communication when grandparents are primary caregivers. Further, few studies have asked about specific topics related to sex, instead asking generally about “sex related topics” or focusing on HIV/AIDS. This research aims to investigate communication on ten specific sex- related topics between grandparents who are primary caregivers and their grandchildren. The primary research aim was to identify facilitators and barriers to grandparent-grandchild communication associated with frequency of communication. A secondary exploratory question was whether frequency of communication and youth satisfaction with communication were associated with youth’s desire for more communication in the future. Methods: The study was conducted in urban and peri-urban central Kenya. A convenience sample of 193 grandparents and 166 twelve to fifteen year old grandchildren were identified by community health workers. A cross sectional survey assessed nine potential barriers or facilitators to communication (e.g., frequency of communication, perceived grandparent knowledge, grandparent sense of responsibility to communication on a given topic) on ten specified sex- related topics (e.g., peer pressure on sex topics, romantic relationships, condoms). Bivariate and multivariable analyses identified significant associations between communication variables and the outcomes of interest. Results: Bivariate regression showed that higher grandchild age, grandchild gender, higher perceived grandparent knowledge, higher perceived grandparent comfort, higher grandparent-reported sense of responsibility, higher grandparent-reported belief that child should be aware of a given topic before initiating in sex, and higher youth’s own comfort during communication, were significantly associated with higher levels of communication frequency. In the multivariable model, higher grandchild age, gender, higher comfort during communication, and higher perceived grandparent knowledge remained significantly associated with higher levels communication frequency. For the secondary research question, higher communication frequency and higher levels of youth satisfaction were both significantly associated with higher levels of youth desire for more communication in bivariate regression, and higher levels of youth’s satisfaction with communication remained significantly associated with higher levels of youth’s desire for more in the adjusted analysis. Conclusions: This study found that several potential barriers and facilitators of communication are associated with both frequency of and youth’s desire for more communication. The association between grandchild age, gender and perceived grandparent knowledge and frequency of communication is similar to findings from other studies that have examined sex-related communication between parent primary caregivers and children. This finding has important implications for understanding grandparent and grandchild communication, and communication on specific topics in a population from Kenya. The positive association between youth satisfaction of and desire for more communication has important education policy and intervention implications, suggesting that if youth are satisfied with the communication with their caregivers, they may want to learn more.

Organisational and systems factors impacting on patient safety in acute care organisations: lessons from four multi-site research studies

Background Patient safety is concerned with preventable harm in healthcare, a subject that became a focus for study in the UK in the late 1990s. How to improve patient safety, presented both a practical and a research challenge in the early 2000s, leading to the eleven publications presented in this thesis. Research question The overarching research question was: What are the key organisational and systems factors that impact on patient safety, and how can these best be researched? Methods Research was conducted in over 40 acute care organisations in the UK and Europe between 2006 and 2013. The approaches included surveys, interviews, documentary analysis and non-participant observation. Two studies were longitudinal. Results The findings reveal the nature and extent of poor systems reliability and its effect on patient safety; the factors underpinning cases of patient harm; the cultural issues impacting on safety and quality; and the importance of a common language for quality and safety across an organisation. Across the publications, nine key organisational and systems factors emerged as important for patient safety improvement. These include leadership stability; data infrastructure; measurement capability; standardisation of clinical systems; and creating an open and fair collective culture where poor safety is challenged. Conclusions and contribution to knowledge The research presented in the publications has provided a more complete understanding of the organisation and systems factors underpinning safer healthcare. Lessons are drawn to inform methods for future research, including: how to define success in patient safety improvement studies; how to take into account external influences during longitudinal studies; and how to confirm meaning in multi-language research. Finally, recommendations for future research include assessing the support required to maintain a patient safety focus during periods of major change or austerity; the skills needed by healthcare leaders; and the implications of poor data infrastructure.

Multi-Scale Dynamic Study of Secondary Impact During Drop Testing of Surface Mount Packages

This dissertation focuses on design challenges caused by secondary impacts to printed wiring assemblies (PWAs) within hand-held electronics due to accidental drop or impact loading. The continuing increase of functionality, miniaturization and affordability has resulted in a decrease in the size and weight of handheld electronic products. As a result, PWAs have become thinner and the clearances between surrounding structures have decreased. The resulting increase in flexibility of the PWAs in combination with the reduced clearances requires new design rules to minimize and survive possible internal collisions impacts between PWAs and surrounding structures. Such collisions are being termed ‘secondary impact’ in this study. The effect of secondary impact on board-level drop reliability of printed wiring boards (PWBs) assembled with MEMS microphone components, is investigated using a combination of testing, response and stress analysis, and damage modeling. The response analysis is conducted using a combination of numerical finite element modeling and simplified analytic models for additional parametric sensitivity studies.

Oil Retention and Pressure Drop in Horizontal and Vertical Suction Lines with R410A / POE ISO 32

In refrigeration systems a small amount of compressor lubricant is entrained in the refrigerant and circulated through the system, where some is retained in each component. The suction line to the compressor has the largest potential for oil retention. This paper presents results from an experimental apparatus that has been constructed to circulate POE (polyolester) oil and R410A at a controlled mass flux, OCR (oil in circulation ratio), and apparent superheat, and to directly measure the pressure drop and mass of oil retained in horizontal and vertical suction lines. The bulk vapor velocity and overall void fraction are determined from direct mass and temperature measurements. The oil retention, pressure drop, and flow regimes near the minimum ASHRAE recommended mass flux condition are explored. It was found that oil retention begins to increase sharply even above the minimum recommended flux, so conditions near the minimum should be avoided. Two relationships were developed to predict the oil retention in the vertical and horizontal suction lines. The average error from the predictions method was 10.9% for the vertical tube, and 7.9% for the horizontal tube.

Epigenetic and oncogenic regulation of SLC16A7 (MCT2) results in protein over-expression, impacting on signalling and cellular phenotypes in prostate cancer

Monocarboxylate Transporter 2 (MCT2) is a major pyruvate transporter encoded by the SLC16A7 gene. Recent studies pointed to a consistent overexpression of MCT2 in prostate cancer (PCa) suggesting MCT2 as a putative biomarker and molecular target. Despite the importance of this observation the mechanisms involved in MCT2 regulation are unknown. Through an integrative analysis we have discovered that selective demethylation of an internal SLC16A7/MCT2 promoter is a recurrent event in independent PCa cohorts. This demethylation is associated with expression of isoforms differing only in 5'-UTR translational control motifs, providing one contributing mechanism for MCT2 protein overexpression in PCa. Genes co-expressed with SLC16A7/MCT2 also clustered in oncogenic-related pathways and effectors of these signalling pathways were found to bind at the SLC16A7/MCT2 gene locus. Finally, MCT2 knock-down attenuated the growth of PCa cells. The present study unveils an unexpected epigenetic regulation of SLC16A7/MCT2 isoforms and identifies a link between SLC16A7/MCT2, Androgen Receptor (AR), ETS-related gene (ERG) and other oncogenic pathways in PCa. These results underscore the importance of combining data from epigenetic, transcriptomic and protein level changes to allow more comprehensive insights into the mechanisms underlying protein expression, that in our case provide additional weight to MCT2 as a candidate biomarker and molecular target in PCa.

Drag & drop

Drag & Drop es una aplicación web diseñada para la creación de problemas a partir de piezas, en la que al profesor se le plantea una nueva posibilidad de evaluar a sus alumnos. La aplicación web servirá como un entorno dedicado a la elaboración de preguntas y respuestas. Para responder a dichas preguntas, se proporcionan unos elementos llamados “piezas” al alumno que se encargará de utilizar para construir su respuesta. A su vez, el profesor al elaborar la pregunta establecerá la solución ideal del problema y el conjunto de “piezas” que los alumnos podrán utilizar para crear las suyas propias. El alumno al terminar la solución de un problema, la enviará al servidor. Este se encargará de evaluarla y comparar la solución del alumno con la solución ideal propuesta por el profesor. Finalmente el profesor será el encargado de examinar el ejercicio y ajustar la calificación, ya sea aceptando la que propone el sistema o indicando una propia.