VictorJuiz/thesis huggingface dataset:
MSE-based Linear Transceiver Designs for Multiuser MIMO Wireless Communications
Keywords: Multiuser downlink
Broadcast channel
Multiple antenna
MIMO systems
Optimization
Convex optimization
Numerical Optimization
Nonlinear programming
Information rates
Diversity methods
Minimum mean squared error
Least mean squares
Linear precoder design
Uplink / downlink duality
Channel estimation and training
Channel feedback

This dissertation designs linear transceivers for the multiuser downlink in multiple-input multiple-output (MIMO) systems. The designs rely on an uplink/downlink duality for the mean squared error (MSE) of each individual data stream. We first consider the design of transceivers assuming channel state information (CSI) at the transmitter. We consider minimization of the sum-MSE over all users subject to a sum power constraint on each transmission. Using MSE duality, we solve a computationally simpler convex problem in a virtual uplink. The transformation back to the downlink is simplified by our demonstrating the equality of the optimal power allocations in the uplink and downlink. Our second set of designs maximize the sum throughput for all users. We establish a series of relationships linking MSE to the signal-to-interference-plus-noise ratios of individual data streams and the information theoretic channel capacity under linear minimum MSE decoding. We show that minimizing the product of MSE matrix determinants is equivalent to sum-rate maximization, but we demonstrate that this problem does not admit a computationally efficient solution. We simplify the problem by minimizing the product of mean squared errors (PMSE) and propose an iterative algorithm based on alternating optimization with near-optimal performance. The remainder of the thesis considers the more practical case of imperfections in CSI. First, we consider the impact of delay and limited-rate feedback. We propose a system which employs Kalman prediction to mitigate delay; feedback rate is limited by employing adaptive delta modulation. Next, we consider the robust design of the sum-MSE and PMSE minimizing precoders with delay-free but imperfect estimates of the CSI. We extend the MSE duality to the case of imperfect CSI, and consider a new optimization problem which jointly optimizes the energy allocations for training and data stages along with the sum-MSE/PMSE minimizing transceivers. We prove the separability of these two problems when all users have equal estimation error variances, and propose several techniques to address the more challenging case of unequal estimation errors.
A Multifaceted Examination of the Central Processes Underlying Vestibular Compensation
Keywords: vestibular
neuron

The vestibular system provides us with sensory information that is essential for maintaining balance and stability. When sensory input is lost due to unilateral vestibular damage (UVD), our ability to maintain stable gaze and posture becomes compromised. Over time, vestibular function is partially restored through a process known as vestibular compensation, which is associated with the rebalancing of activity in the vestibular nuclear complex (VNC) of the brainstem. However, the physiological mechanisms associated with vestibular compensation remain elusive. We addressed several different experimental objectives pertaining to plasticity and sensory adaptation associated with vestibular compensation. First, we demonstrated that systemic manipulation of γ-amino-butyric acid type B (GABAB) receptors altered the course of vestibular behavioural recovery within the first several hours after UVD. Second, we showed that immunohistochemical labeling of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit GluR4 was elevated in the VNC on the intact compared to lesioned side acutely following UVD. Third, we produced preliminary data suggesting that excitatory responses to vestibular nerve stimulation may be acutely potentiated by UVD on the intact side. Finally, we established that rapid sensory adaptation may increase the dynamic ranges of vestibular neurons and perhaps improve limited vestibular reflex function in the long term. Acutely following UVD, potentiation of vestibular nerve synapses appear to be associated with an increase in GluR4 subunit expression in the contralesional VNC. Also, such potentiation could be enhanced by acute modifications in pre-synaptic GABAB receptor activation. In the long term, and independent of these plastic changes, sensory adaptation may enable the vestibular system to overcome the persistent limitations imposed by UVD.
Surviving the Sasachacuy Tiempu [Difficult Times]: The Resilience of Quechua Women in the Aftermath of the Peruvian Armed Conflict
Keywords: resilience
posttrauma responses
political violence
indigenous women
gender based violence

Resilience and post trauma responses often coexist, however, for the past decades, the trauma paradigm has served as the dominant explanatory framework for human suffering in post-conflict environments, while the resilience of individuals and communities affected by mass violence has not been given equal prominence. Consequently, mental health interventions in post-conflict zones often fail to respond to local realities and are ill equipped to foster local strengths. Drawing primarily from trauma, feminist and structural violence theories, this study strengthens understanding of adult resilience to traumatic exposure by examining the resilience of Quechua women in the aftermath of the political violence in Peru (1980-2000), and their endurance of racially and gender-targeted violence. The study uses a cross sectional survey to examine the resilience and posttraumatic responses of 151 Quechua women. Participants were recruited from an urban setting and three rural villages in Ayacucho, Peru. The study examines the associations between resilience, past exposure to violence, current life stress and post-trauma related symptoms as well as the individual and community factors associated with the resilience of Quechua women. In doing so, this study makes a unique contribution by simultaneously examining posttraumatic responses and resilience in a post-conflict society, an area with a dearth of research. Results indicate that resilience was not associated with overall posttraumatic stress related symptoms, but instead higher resilience was associated with lower level of avoidance symptoms and therefore with lesser likelihood of chronic symptoms. Findings also demonstrate that enhanced resilience was associated with women’s participation in civic associations, as well as being a returnee of mass displacement. Lower resilience was instead associated with lower levels of education, absence of income generated from a formal employment and the experience of sexual violence during the conflict. These results were triangulated with qualitative findings, which show that work, family, religion, and social participation are enhancing factors of resilience. The study highlights the courage and resilience of Quechua women despite persistent experiences of everyday violence. The importance to situate trauma and resilience within historical processes of oppression and social transformation as well as other implications for social work practice and research are discussed.
Experiencing Everyday Prejudice of a Concealabe Stigma: Jews in a non-Jewish World
Keywords: social psychology
stigma
prejudice
everyday prejudice
concealable stigma
Jews
Judaism
anti-semitism
qualitative methodology
life history method

Dion (2001) observed that being the target of stigma and prejudice has a “demonstrable, negative effect upon the individual.” While blatant prejudice has lessened there has been little change in the rate of subtle forms of stigma and prejudice (Wilson, 1996). Recent trends in the literature acknowledge the importance of everyday reminders of difference or prejudice for women, racial minorities and ethnic groups (Swim, 2003). Jews with a long history as targets of stigma, prejudice and discrimination are an excellent example of a modern concealable stigma. Previous research into the Jewish experience has been influenced by concerns about group survival and has not included specific investigation of the experience of the target of stigma in interaction with perpetrators. Using a qualitative life history methodology this research sheds light on the experience of minority group members with a concealable stigma. Jewish adults with diverse backgrounds were interviewed using a semi-structured life history approach. The first layer of analysis identified six overarching themes – unshakeable loyalty to Jewish identity; importance of belonging; living Jewishness in a way that is meaningful; concerns about visibility of Jewishness; concerns about personal and group vulnerability including references to the Holocaust; and everyday encounters with prejudice. These themes share commonalities with Fiske’s (2004) social needs expressed in a Jewish context. The second layer of analysis developed a model of an encounter with everyday prejudice. This model identifies the overriding importance of contextual influences on perceptions of an encounter in turn influencing the reaction and response. Following the example of Miller and Kaiser (Miller, 2006; 2001b), these encounters are seen as stressful events which can be understood using the framework of the stress and coping model (Lazarus & Folkman, 1984). The results show the subtle but important impact of everyday prejudice. As well as providing a means of understanding the experience of these individuals the results have implications for both therapeutic and psychoeducational interventions.
Maltreatment in the Father-child Relationship: An Exploration of Problematic Relational Dynamics
Keywords: child maltreatment
domestic violence
fathers

Despite the high prevalence of father-perpetrated maltreatment, relatively little empirical attention has been given to men who abuse and neglect their children (Dubowitz, 2006, 2009; Haskett, Marziano, & Dover, 1996). To further our understanding, the current dissertation explored father-child relational dynamics that underlie risk for child maltreatment. In the first study, data from a sample of 121 maltreating fathers were used to discern differential patterns of parenting dynamics using both theoretical and statistical approaches to classification. It was hypothesized that fathers would show problems predominantly in one of five areas: emotional unavailability; negative attribution, harshness, and rejection; developmentally inappropriate interaction; poor psychological boundaries; and exposure of a child to hostile inter-parental relations. Contrary to expectation, little support was obtained for the predominant problem hypothesis. Although methodological limitations may play a role, results indicated that men were more clearly differentiated by the degree of severity evidenced across their problematic parent-child interactions, than by differences in the specific pattern of problems they experienced. An interesting finding from Study 1 was that increasingly severe relational problems were associated with a misprioritization of parent and child needs. Study 2 further explored this dynamic by revising and re-evaluating a self-report measure of men’s ability to balance needs in the father-child relationship. Data from two samples (93 community fathers and 85 maltreating fathers) provided mixed results: Support was obtained for the internal consistency and construct validity of the image-emotional needs subscale of the measure; however, minimal support was obtained for the personal needs subscale. Furthermore, in contrast to expectation, discriminant validity was not obtained for either subscale, as maltreating fathers reported a better ability to balance needs on both scales than fathers drawn from a community sample. Social desirability was one of several factors deemed to play a key role in this finding. Each study’s contribution to the field is reviewed, along with discussion of limitations and future directions.
Inter-professional Clinical Practice Guideline for Vocational Evaluation following Traumatic Brain Injury
Keywords: clinical practice guidelines
vocational rehabilitation
traumatic brain injury
evidence-based practice
health plan implementation
return to work
employment
work capacity evaluation
brain injury
vocational evaluation
work assessment
job performance
work performance
employment status
re-employment
review
work integration
work re-integration
brain injuries
practice guideline
knowledge transfer
knowledge translation
implementation
occupational therapy
neurological rehabilitation
knowledge exchange
research utilization
continuing professional development
quality improvement
practice change
change management
health care technology
implementation research

Due to physical, cognitive and emotional impairments, many individuals are unemployed or under-employed following a traumatic brain injury. The research evidence links the rigour of a vocational evaluation to future employment outcomes. Despite this link, no specific guidelines exist for vocational evaluations. Using the research evidence and a diverse panel of clinical and academic experts, the primary objective of this doctoral research was to develop an inter-professional clinical practice guideline for vocational evaluation following traumatic brain injury. The objective of the guideline is to make explicit the processes and factors relevant to vocational evaluation, to assist evaluators (i.e. clients, health and vocational professionals, and employers) in collaboratively determining clients’ work abilities and developing recommendations for work entry, re-entry or vocational planning. The steps outlined in the Canadian Medical Association's Handbook on Clinical Practice Guidelines were utilized to develop the guideline and include the following: 1) identifying the guideline’s objective/questions; 2) performing a systematic literature review; 3) gathering a panel; 4) developing recommendations; 4) guideline writing; 5) pilot testing. The resulting guideline includes 17 key recommendations within the following seven domains: 1) evaluation purpose and rationale; 2) initial intake process; 3) assessment of the personal domain; 4) assessment of the environment; 5) assessment of occupational/job requirements; 6) analysis and synthesis of assessment results; and 7) development of evaluation recommendations. Results from an exploratory study of the guideline’s implementation by occupational therapists in their daily practices revealed that clinicians used the guideline to identify practice gaps, systematize their evaluation processes, enhance inter-professional and inter-stakeholder communication, and re-conceptualize their vocational evaluations across disability groups. Statistically significant improvements were also noted in clients’ participation scores on the Mayo-Portland Adaptability Inventory–4 following guideline use. This guideline may be applicable to individuals with TBI, clinicians, health and vocational professionals, employers, professional organizations, administrators, policy makers and insurers.
Dissecting the Role of Morphogenesis in the Origins of the First Two Cell Lineages in the Mouse Embryo
Keywords: mouse
epithelium
polarity
polarization
blastocyst
cell adhesion
E-cadherin
Cdx2
aPKC
ROCK
Yap
embryo
PKC zeta
Lats
Oct4

Although the mechanisms underlying the divergence of the first cell types in the mouse, the trophectoderm (TE) and the inner cell mass (ICM) have received considerable attention, the upstream signals stimulating their divergence are not well understood. The work presented here examines the roles that morphogenetic factors such as cell adhesion and polarization play in the development of these cell types. I show here that in embryos completely lacking both maternal and zygotic E-cadherin, the normal epithelial morphology of outer cells is disrupted but individual cells still initiate TE and ICM-like fates. A larger proportion of cells than normal expressed TE markers like Cdx2 (a homeodomain containing transcription factor), suggesting that formation of an organized epithelium is not necessary for TE-specific gene expression. Individual cells in such embryos still generate an apical-like domain that correlates with elevated Cdx2 expression. I also show that repolarization can occur in isolated early ICMs from both wild type and Cdx2 mutant embryos, indicating that Cdx2 is not required to initiate polarity. Importantly, I demonstrate a critical role for the Rho-associated kinase ROCK in apical-basal polarization of preimplantation blastomeres. Loss of apical-basal polarization leads to a reduction of Cdx2 expression in outer blastomeres due to activation of Lats1/2 kinase and reduced nuclear Yap1. The influence of polarization upon Lats1/2 kinase is stage-dependent however, as apolar 8-cell blastomeres retain nuclear Yap1. Cell position appears to serve as an additional cue for nuclear localization of Yap and Cdx2 expression from the 8-cell stage to E3.5. Cell polarization plays an additional role in the embryo of maintaining cells in consistently outer or inner positions, thus ensuring that Cdx2 is expressed exclusively in the developing TE. The results of this work demonstrate important links between morphogenesis, cell fate and patterning in the preimplantation embryo. Both cell polarization and cell position act as critical cues to determine gene expression and to pattern this expression within the embryo.
Lie 2-algebras as Homotopy Algebras Over a Quadratic Operad
Keywords: Operads
Categorification

We begin by discussing motivation for our consideration of a structure called a Lie 2-algebra, in particular an important class of Lie 2-algebras are the Courant Algebroids introduced in 1990 by Courant. We wish to attach some natural definitions from operad theory, mainly the notion of a module over an algebra, to Lie 2-algebras and hence to Courant algebroids. To this end our goal is to show that Lie 2-algebras can be described as what are called \emph{homotopy algebras over an operad}. Describing Lie 2-algebras using operads also solves the problem of showing that the equations defining a Lie 2-algebra are consistent. Our technical discussion begins by introducing some notions from operad theory, which is a generalization of the theory of operations on a set and their compositions. We define the idea of a quadratic operad and a homotopy algebra over a quadratic operad. We then proceed to describe Lie 2-algebras as homotopy algebras over a given quadratic operad using a theorem of Ginzburg and Kapranov. Next we briefly discuss the structure of a braided monoidal category. Following this, motivated by our discussion of braided monoidal categories, a new structure is introduced, which we call a commutative 2-algebra. As with the Lie 2-algebra case we show how a commutative 2-algebra can be seen as a homotopy algebra over a particular quadratic operad. Finally some technical results used in previous theorems are mentioned. In discussing these technical results we apply some ideas about distributive laws and Koszul operads.
Understanding and Addressing Barriers: Engaging Adolescents in Mental Health Services
Keywords: evidence-based practice
treatment engagement
adolescents
Mental Health Services Research

This randomized-controlled pilot study explored the impact of a pretreatment, telephone engagement intervention on adolescents’ (ages 13-19) initial mental health service attendance (i.e., the first 3 counseling sessions) and four secondary outcome variables (i.e., autonomous/ controlled treatment motivation, self-efficacy, and working alliance). Twenty-seven adolescents received the engagement intervention and completed assessments and 24 adolescents completed assessments only. Both groups completed follow-up assessments 6 weeks after study enrollment. Associations between the outcome variables and initial treatment attendance were explored. The extent to which demographic variables (i.e., age, gender, race, immigration status, and residence in low income neighbourhoods), psychological distress, and self-reported barriers (i.e., mismatched treatment expectations and external demands) were associated with treatment attendance was also explored. The primary findings from this pilot study indicated that adolescents who received the engagement intervention had greater initial treatment attendance (M=2.11, SD=1.01) than the assessment only group (M=1.54, SD=1.22), but the difference only approached significance. Moreover, no significant between-group differences in the secondary outcome variables were found. Paired samples t-tests were used to examine changes in autonomous/controlled treatment motivation and self-efficacy within groups between baseline and follow-up. The results of the paired samples t-tests indicated that that the experimental and control groups both demonstrated a significant decrease in controlled motivation at follow-up. In addition, the control group demonstrated a significant decrease in autonomous treatment motivation at follow-up. Post hoc analyses, using correlation and linear regression analyses, explored the associations between initial attendance and the secondary outcome variables, psychological distress, self-reported barriers, and demographic variables. A negative association between age, self-reported barriers and initial attendance was found. A positive association was found between working alliance and initial attendance. While the majority of adolescents who participated in this research lived in low income neighbourhoods and nearly half were second generation immigrants, these demographic variables were not associated with initial treatment attendance. Although the engagement intervention had a medium effect on initial treatment attendance, this difference was not statistically significant. Future research with a larger sample size and longer follow-up is needed to determine the effectiveness of the engagement intervention.