Hierarchical Reconstruction Method for Solving Ill-posed Linear Inverse Problems

We present a detailed analysis of the application of a multi-scale Hierarchical Reconstruction method for solving a family of ill-posed linear inverse problems. When the observations on the unknown quantity of interest and the observation operators are known, these inverse problems are concerned with the recovery of the unknown from its observations. Although the observation operators we consider are linear, they are inevitably ill-posed in various ways. We recall in this context the classical Tikhonov regularization method with a stabilizing function which targets the specific ill-posedness from the observation operators and preserves desired features of the unknown. Having studied the mechanism of the Tikhonov regularization, we propose a multi-scale generalization to the Tikhonov regularization method, so-called the Hierarchical Reconstruction (HR) method. First introduction of the HR method can be traced back to the Hierarchical Decomposition method in Image Processing. The HR method successively extracts information from the previous hierarchical residual to the current hierarchical term at a finer hierarchical scale. As the sum of all the hierarchical terms, the hierarchical sum from the HR method provides an reasonable approximate solution to the unknown, when the observation matrix satisfies certain conditions with specific stabilizing functions. When compared to the Tikhonov regularization method on solving the same inverse problems, the HR method is shown to be able to decrease the total number of iterations, reduce the approximation error, and offer self control of the approximation distance between the hierarchical sum and the unknown, thanks to using a ladder of finitely many hierarchical scales. We report numerical experiments supporting our claims on these advantages the HR method has over the Tikhonov regularization method.

Exporting the racial republic: African colonization, national citizenship, and the transformation of U.S. expansion, 1776-1864

The effort to create a colony of African Americans on the west coast of Africa was one of the most celebrated and influential movements in the United States during the first half of the 19th century. While historians have often viewed African colonization through the lens of domestic anti-slavery politics, colonization grew from an imperial impulse which promised to transform the identities of black colonists and indigenous Africans by helping them to build a democratic nation from the foundation of a settler colony. By proposing that persons of African descent could eventually become self-governing subjects, the liberal framework behind colonization offered the possibility of black citizenship rights, but only within racially homogenous nation-states, which some proponents of colonization imagined might lead to a “United States of Africa.” This dissertation examines how the notion of expanding democratic ideals through the export of racial nationhood was crucial to the appeal of colonization. It reveals how colonization surfaced in several crucial debates about race, citizenship, and empire in the antebellum United States by examining discussions about African Americans’ revolutionary claims to political rights, the bounds of US territorial expansion, the removal of native populations in North America, and the racialization of national citizenship, both at home and abroad. By examining African colonization from these perspectives, this dissertation argues that the United States’ efforts to construct a liberal democracy defined by white racial identity were directly connected to the nation’s emerging identity as a defender and exporter of political liberty throughout the world.

La actividad laboral de las familias africanas y latinoamericanas reagrupadas en la España mediterránea

La investigación se basa en los resultados de una encuesta realizada en 2009-2010, por el equipo investigador, a 348 inmigrados reagrupantes africanos y a 457 latinoamericanos que residen en las provincias litorales entre Girona y Almería. La información que se ofrece está referida a los aspectos laborales de estos dos colectivos continentales, tanto a escala del conjunto territorial indicado como para tres subáreas incluidas en él: Cataluña litoral, Comunidad Valenciana y Murcia-Almería; según los temas, se trata por separado a los reagrupantes y a los subgrupos familiares que conviven en España (reagrupantes, cónyuges, hijos). El estudio se centra en las estructuras de empleo por sectores económicos. También se estudian las redes migratorias, tan decisivas en la orientación de estos flujos hacia España, la regulación laboral de estos trabajadores, la repercusión de la crisis actual en los empleos de las familias reagrupadas (paro, número de ocupados por familia e ingresos), la satisfacción laboral de los miembros de las familias (horas de trabajo, problemas laborales y salariales) y la estabilidad laboral (antigüedad en el empleo, cursos de formación profesional, trabajo actual y expectativas del inmigrante). El recorrido por los temas laborales indicados, vinculados a los distintos grupos continentales y familiares y a las diferentes escalas territoriales, concluyen en mostrar situaciones económicas y sociales muy diferentes entre africanos y latinoamericanos, y entre los que residen en Cataluña litoral y en Murcia-Almería, en lo que intervienen, entre otras causas, los distintos «capitales» personales aportados por los dos colectivos continentales para acceder al empleo (formación, idioma, …) y las diferentes estructuras económicas de los territorios estudiados. Los africanos y los que residen en las provincias meridionales son los que presentan peores situaciones socioeconómicas.

La reagrupación familiar de africanos y latinoamericanos en la España mediterránea: dinámicas y estructuras sociodemográficas

Los extranjeros autorizados en 2006-2009 a residir en España por motivos de reagrupación familiar, muestran la importancia que ha alcanzado esta forma de inmigración en el total de nuevos extranjeros empadronados. La investigación se basa en una encuesta específica a reagrupantes africanos y latinoamericanos, que también informan sobre sus familiares reagrupados, hayan utilizado, o no, las leyes de reagrupación. Africanos y latinoamericanos ofrecen dinámicas y estructuras sociodemográficas muy diferentes, a resultas, entre otras causas, de la antigüedad de sus flujos, su fecundidad, su dominio del idioma español, su nivel de instrucción, sus posibilidades de ingresos, su estructura por sexo y edad, tamaño de las familias reagrupadas, etc. Se ofrece información para los dos colectivos continentales y para los subgrupos familiares —reagrupantes, cónyuges, hijos, progenitores y otros familiares—, y se utilizan escalas del conjunto estudiado y de ámbitos territoriales —Cataluña litoral, Comunidad Valenciana, Murcia-Almería—. Los africanos concentran los aspectos estructurales más negativos —idioma español, instrucción, ingresos,…—, pero también son los que declaran intenciones más firmes y generalizadas de permanencia en España. Las conclusiones orientan sobre el futuro de estos flujos.

BLACK, MALE, AND HIGH-ACHIEVING: AN EXAMINATION OF A RISK FACTOR AND CULTURAL RESOURCES FOR BLACK MALE ACADEMIC ACHIEVEMENT

Black boys are confronted with unique educational circumstances. They are often misdiagnosed and misplaced into special education programs (Bush-Daniels, 2008; Patton, 1998; Terman et al., 1996). Additionally, they are less likely to be enrolled in gifted and talented programs, even if their former achievements reflect their aptitude to succeed (Black Alliance for Educational Options, n.d.; Moore & Flowers, 2012). Given these statistics, a considerable emphasis has been placed on the causes and the consequences of low/under achievement for this population. As a result, the experiences of Black males who are achieving have been greatly neglected. Moreover, little is known about the factors that facilitate academic achievement among high-achieving Black boys. In an effort to bring the heterogenic nature of schooling experiences for Black boys to light, the present study examined the influence risk and protective factors had on the academic experiences of high-achieving Black boys. Grounded in the risk and resilience framework and the Integrative Model for the Study of Minority Youth Development, this study explored whether the high-achieving Black high school boys in this sample (n =88) reported experiencing discrimination (i.e. academic-based) and how this academic-based discrimination related to their 1) academic performance (i.e. GPA), 2) perceptions of math ability, and 3) race-based academic self-concept. In addition to exploring how academic-based discrimination was linked to academic achievement, this study examined how cultural resources such as racial socialization messages and racial identity related to academic achievement. Specifically, cultural socialization, preparation for bias, egalitarianism, private regard and public regard were evaluated alongside the three academic outcomes under study. Finally, the study explored whether aspects of racial socialization or racial identity buffered the effects of discrimination on any of the outcomes. Interestingly, the race/ethnicity of the student mattered for how students perceived their math ability. The risk factor academic-based discrimination was linked to academic performance. Cultural resources cultural socialization, preparation for bias, and private regard were linked to various academic outcomes of interest. There was only one significant moderating effect: a high private regard buffered the relationship between academic-based discrimination and race-based academic self-concept. Limitations and implications of this study are discussed.

A Phenomenological Exploration of Black Male Law Enforcement Officers' Perspectives of Racial Profiling and Their Law Enforcement Career Exploration and Commitment

This phenomenological study explored Black male law enforcement officers’ perspectives of how racial profiling shaped their decisions to explore and commit to a law enforcement career. Criterion and snow ball sampling was used to obtain the 17 participants for this study. Super’s (1990) archway model was used as the theoretical framework. The archway model “is designed to bring out the segmented but unified and developmental nature of career development, to highlight the segments, and to make their origin clear” (Super, 1990, p. 201). Interview data were analyzed using inductive, deductive, and comparative analyses. Three themes emerged from the inductive analysis of the data: (a) color and/or race does matter, (b) putting on the badge, and (c) too black to be blue and too blue to be black. The deductive analysis used a priori coding that was based on Super’s (1990) archway model. The deductive analysis revealed the participants’ career exploration was influenced by their knowledge of racial profiling and how others view them. The comparative analysis between the inductive themes and deductive findings found the theme “color and/or race does matter” was present in the relationships between and within all segments of Super’s (1990) model. The comparative analysis also revealed an expanded notion of self-concept for Black males – marginalized and/or oppressed individuals. Self-concepts, “such as self-efficacy, self-esteem, and role self-concepts, being combinations of traits ascribed to oneself” (Super, 1990, p. 202) do not completely address the self-concept of marginalized and/or oppressed individuals. The self-concept of marginalized and/or oppressed individuals is self-efficacy, self-esteem, traits ascribed to oneself expanded by their awareness of how others view them. (DuBois, 1995; Freire, 1970; Sheared, 1990; Super, 1990; Young, 1990). Ultimately, self-concept is utilized to make career and life decisions. Current human resource policies and practices do not take into consideration that negative police contact could be the result of racial profiling. Current human resource hiring guidelines penalize individuals who have had negative police contact. Therefore, racial profiling is a discriminatory act that can effectively circumvent U.S. Equal Employment Opportunities Commission laws and serve as a boundary mechanism to employment (Rocco & Gallagher, 2004).

Looking for Daisy : constructing teacher identities

Research on teacher identities is both important and increasing. In this forum contribution I re-interpret assertions about an African American science teacher’s identities in terms of Jonathon Turner’s (2002) constructs of role identity and sub-identity. I contest the notion of renegotiation of identities, suggesting that particular role identities can be brought to the foreground and then backgrounded depending on the situation and the need to confirm a sub-identity. Finally, I recommend the inclusion of teachers’ voices in identity research through greater use of co-authoring roles for teachers.

'Black is beautiful', and Indigenous : Aboriginal authorship in Australian popular music

The ‘black is beautiful’ movement began in the United States in the early sixties, and changed mainstream attitudes towards the body, fashion and personal aesthetics, gaining African American people a new sense of pride in being – and being called – ‘black’. In Australia the movement also had implications for changing the political meanings of ‘black’ in white society. However, it is not until the last decade, through the global influence of Afro-American music, that a distinctly Indigenous sense of black sexiness has captured the attention of mainstream audiences. The article examines such recent developments, and suggests that, through the appropriation of Afro-American aesthetics and styles, Indigenous producers and performers have developed new forms of Indigenous public agency, demonstrating that black is beautiful, and Indigenous.

Ureaplasma speioces are associated with chorioamnionitiis in late preterm placentas

Background: Preterm birth is a major cause of neonatal morbidity and mortality, with 75% of preterm births occurring late preterm. Previous studies have investigated the microbial diversity within placentas delivered early preterm but there has been no investigation of the prevalence of bacteria, particularly Ureaplasma spp. in late preterm placentas. Method: Women giving birth late preterm (320 – 366 weeks of gestation) in Cincinnati were recruited for this study. Samples of chorioamnion were collected aseptically at the time of delivery, shipped to QUT and tested for Ureaplasma spp. and other bacteria by culture and/or PCR assays. The presence of bacteria was correlated with adverse pregnancy outcomes, including histological chorioamnionitis (tissue sections read by US pathologists). Results: To date, Ureaplasma spp. have been detected in 15/270 (5.5%) of placentas by culture and 19/270 (7%) by PCR. Ureaplasma presence correlated with histological chorioamnionitis (12/19%; 63%). However, the presence of other bacteria was not associated with chorioamnionitis (5%). Chorioamnionitis was unevenly distributed in ethnic groups, with a higher incidence in African-Americans’ (6/7; 86%), compared to Caucasians’ (6/12; 50%) who were colonised with ureaplasmas. Conclusion: This study is the first to report the prevalence of ureaplasmas in women (7%) who deliver late preterm. Ureaplasma spp. were associated with a higher incidence of chorioamnionitis (63% compared to 15% for non-infected women). This data strongly suggests that ureaplasmas are a cause of late preterm deliveries and African-American women are at greater risk of chorioamnionitis.

Book Review [White Bound: Nationalists, Antiracists, and the Shared Meanings of Race, by MW Hughey]

Dr Kathy A. Mills provides a critical synthesis and review of the new book by Matthew W. Hughey entitle: White Bound: Nationalists, Antiractists, and the Shared Meanings of Race, published by Standford University Press in 2012. A sample of Dr Mills' review reads: "The author positions race squarely at the center to challenge the shared assumptions of white supremacist logic on both sides of the debate. The clever thesis blurs the boundaries between “good whites” and “bad whites”, rendering the white reader intellectually stimulated, but existentially unchanged – White Bound – as the author ponders: “Perhaps we have met the enemy, and he [it] is us” (p.193)...The unanswered question that remains is: How do we resist the various “shades” of white supremacy to pursue counter-hegemonic practices?"

Are two threats worse than one? The effects of face race and emotional expression on fear conditioning

Facial cues of racial outgroup or anger mediate fear learning that is resistant to extinction. Whether this resistance is potentiated if fear is conditioned to angry, other race faces has not been established. Two groups of Caucasian participants were conditioned with two happy and two angry face conditional stimuli (CSs). During acquisition, one happy and one angry face were paired with an aversive unconditional stimulus whereas the second happy and angry faces were presented alone. CS face race (Caucasian, African American) was varied between groups. During habituation, electrodermal responses were larger to angry faces regardless of race and declined less to other race faces. Extinction was immediate for Caucasian happy faces, delayed for angry faces regardless of race, and slowest for happy racial outgroup faces. Combining the facial cues of other race and anger does not enhance resistance to extinction of fear.

Do we need to prescribe exercise differently for premenopausal and postmenopausal women?

The article by Kretzschmar et al 1 in this issue of Menopause details a study investigating the effect of a mild-intensity aerobic exercise training program on markers of mortality risk in both pre- and post-menopausal African American women. The findings of this study showed that aerobic exercise training was successful in improving some markers of cardiovascular disease (CVD) and mortality in post-menopausal women. The premise of this study, however, does suggest that increased exercise intensity may be required in post-menopausal women as opposed to pre-menopausal women to achieve the same decreased changes in CVD markers. The outcome of the study is thus of interest to the readers of Menopause and to all those who provide health care to postmenopausal women, as it suggests that higher levels of exercise intensity or perhaps additional interventions may need to be considered in this population to further decrease mortality risk. The study therefore, has greater implications than simply the suggestion of tailoring exercise interventions generally; rather, the publication highlights the importance of prescribing exercise as medicine in a tailored fashion for women depending on their menopausal status.

Racial differences in physical activity among breast cancer survivors : implications for breast cancer care

Background: Physical activity after breast cancer diagnosis is associated with improved survival. This study examines levels of and changes in physical activity following breast cancer diagnosis, overall and by race. Methods: The Carolina Breast Cancer Study, Phase III, assessed pre- and post-diagnosis physical activity levels in a cohort of 1,735 women, aged 20-74, diagnosed with invasive breast cancer between 2008 and 2011 in 44 counties of North Carolina. Logistic regression and analysis of variance were used to examine whether demographic, behavioral and clinical characteristics were associated with activity levels. Results: Only 35% of breast cancer survivors met current physical activity guidelines post-diagnosis. A decrease in activity following diagnosis was reported by 59% of patients, with the average study participant reducing their activity by 230 minutes (95% CI: 190, 270). Following adjustment for potential confounders, when compared to white women, African-American women were less likely to meet national physical activity guidelines post-diagnosis (odds ratio: 1.38, 95% CI: 1.01, 1.88), reported less weekly post-diagnosis physical activity (182 vs. 215 minutes; p=0.13), and reported higher average reductions in pre- versus post-diagnosis weekly activity (262 vs. 230 minutes; p-value = 0.13). Conclusion: Despite compelling evidence demonstrating the benefits of physical activity post-breast cancer, it is clear that more work needs to be done to promote physical activity in breast cancer patients, especially among African-American women.

Indexes of insulin resistance and secretion in obese children and adolescents : a validation study

OBJECTIVE To assess the concurrent validity of fasting indexes of insulin sensitivity and secretion in - obese prepubertal (Tanner stage 1) children and pubertal (Tanner stages 2-5) glucose tolerance test (FSIVGTT) as a criterion measure. RESEARCH DESIGN AND METHODS Eighteen obese children and adolescents (11 girls and 7 boys, mean age 12.2 +/- 2.4 years, mean BMI 35.4 +/- 6.2 kg/m(2), mean BMI-SDS 3.5 +/- 0.5, 7 prepubertal and I I pubertal) participated in the study. All participants underwent an insulin-modified FSIVGTT on two occasions, and 15 repeated this test a third time (mean 12.9 and 12.0 weeks apart). S-i measured by the FSIVGTT was compared with homeostasis model assessment (HOMA) of insulin resistance (HOMA-IR), quantitative insulin-sensitivity check index (QUICKI), fasting glucose-to-insulin ratio (FGIR), and fasting insulin (estimates of insulin sensitivity derived from fasting samples). The acute insulin response (AIR) measured by the FSIVGTT was compared with HOMA of percent beta-cell function (HOMA-beta%), FGIR, and fasting insulin (estimates of insulin secretion derived from fasting samples). RESULTS There was a significant negative correlation between HOMA-IR and S-i (r = -0.89, r = -0.90, and r = -0.81, P < 0.01) and a significant positive correlation between QUICKI and S-i (r = 0.89, r = 0.90, and r = 0.81, P < 0.01) at each time point. There was a significant positive correlation between FGIR and S-i (r = 0.91, r = 0.91, and r = 0.82, P < 0.01) and a significant negative correlation between fasting insulin and S-i (r = -90, r = -0.90, and r = -0.88, P < 0.01). HOMA-beta% was not as strongly correlated with AIR (r = 0.60, r = 0.54, and r = 0.61, P < 0.05). CONCLUSIONS HOMA-IR, QUICKI, FGIR, and fasting insulin correlate strongly with S-i assessed by the FSIVGTT in obese children and adolescents. Correlations between HOMA-β% FGIR and fasting insulin, and AIR were not as strong. Indexes derived from fasting samples are a valid tool for assessing insulin sensitivity in prepubertal and pubertal obese children.

Physical activity patterns of inner-city elementary schoolchildren

Purpose This study aimed to objectively measure the physical activity (PA) characteristics of a racially and ethnically diverse sample of inner-city elementary schoolchildren and to examine the influence of sex, race/ethnicity, grade level, and weight status on PA. Methods A total of 470 students in grades 4-6 from six inner-city schools in Philadelphia wore an ActiGraph GT3X+ accelerometer (Actigraph, Pensacola, FL) for up to 7 d. The resultant data were uploaded to a customized Visual Basic EXCEL macro to determine the time spent in sedentary (SED), light-intensity PA (LPA), and moderate- to vigorous-intensity PA (MVPA). Results On average, students accumulated 48 min of MVPA daily. Expressed as a percentage of monitoring time, students were sedentary for 63% of the time, in LPA 31% of the time, and in MVPA 6% of the time. Across all race/ethnicity and grade level groups, boys exhibited significantly higher levels of MVPA than girls did; fifth-grade boys exhibited significantly lower MVPA levels than fourth-and sixth-grade boys did, and sixth-grade girls exhibited significantly lower MVPA levels than fourth-and fifth-grade girls did. Hispanic children exhibited lower levels of MVPA than children from other racial/ethnic groups did, and overweight and obese children exhibited significantly lower MVPA levels than children in the healthy weight range did. Across the entire sample, only 24.3% met the current public health guidelines for PA. Physical inactivity was significantly greater among females, Hispanics, and overweight and obese students. Conclusions Fewer than one in four inner-city schoolchildren accumulated the recommended 60 min of MVPA daily. These findings highlight the need for effective and sustainable programs to promote PA in inner-city youth.