Say It Loud: An Action Research Project Examining the Afrivisual and Africology, Looking for Alternative African American Community College Teaching Strategies

For this study, the researcher sought to implement a visual arts-based Afrivisual to help inspire, motivate and empower African American students in gaining a culturally relevant education in Euro-American-centered schools. Using the Afrivisual in this work as an action-oriented tool the researcher sought to expose African American students to an African historical context. This research project utilized three African-centered theoretical frameworks: (1) Afrocentricity, (2) Africana Philosophy, and (3) Africana Critical Theory. The problem this work addresses is found in four areas, (1) American history is Eurocentric, (2) African history has been distorted, (3) Africa’s contribution to world civilization has been ignored, and (4) African American students have suffered from identity issues. The primary purpose of the study was to show how African American students may react to culturally relevant exposure to African history and to investigate if exposure to African history is culturally relevant for them. The researcher also hoped to present an effective strategy for Black students from an African-centered point of view. The central questions of this study were, “How do native-born African American community college students respond to a culturally relevant visual tool? What experiences have they had with history? How has their exposure to history affected them?” Both quantitative and qualitative phases of this study were based on data and interviews with African American community college students. Descriptive statistics, including frequency percentages shown in tables were used to present the questionnaire data. Qualitative coding techniques were used to present the focus group data. The qualitative phase of the study highlighted the introduction of the Afrivisual, a visual arts-based and culturally relevant educational tool. There were similarities between the survey sample and the interview sample. The quantitative and qualitative data combined to show the strong desire African American students have to study African history, African civilizations, and to learn about their African ancestors. The triangulation of the data revealed that African American students who were found to be proud to be Black, vowed to be vigilant in future history classes about what they’re being taught, and to present questions about African history. The students also expressed a tremendous need to share what they’ve learned about African history with other African Americans. The significance of this study is that the Afrivisual can be a potentially effective teaching strategy. Also additional researchers may be able to build upon the findings of this inquiry by using another media form of the Afrivisual. Lastly, it exposed weaknesses in the self-hatred thesis as it applies to African American adults, and called for the groundbreaking theoretical framework to be revisited

Exact Free Distance and Trapping Set Growth Rates for LDPC Convolutional Codes

Ensembles of (J,K)-regular low-density parity-check convolutional (LDPCC) codes are known to be asymptotically good, in the sense that the minimum free distance grows linearly with the constraint length. In this paper, we use a protograph-based analysis of terminated LDPCC codes to obtain an upper bound on the free distance growth rate of ensembles of periodically time-varying LDPCC codes. This bound is compared to a lower bound and evaluated numerically. It is found that, for a sufficiently large period, the bounds coincide. This approach is then extended to obtain bounds on the trapping set numbers, which define the size of the smallest, non-empty trapping sets, for these asymptotically good, periodically time-varying LDPCC code ensembles.Comment: To be presented at the 2011 IEEE International Symposium on Information Theor

Threshold Analysis of Non-Binary Spatially-Coupled LDPC Codes with Windowed Decoding

In this paper we study the iterative decoding threshold performance of non-binary spatially-coupled low-density parity-check (NB-SC-LDPC) code ensembles for both the binary erasure channel (BEC) and the binary-input additive white Gaussian noise channel (BIAWGNC), with particular emphasis on windowed decoding (WD). We consider both (2,4)-regular and (3,6)-regular NB-SC-LDPC code ensembles constructed using protographs and compute their thresholds using protograph versions of NB density evolution and NB extrinsic information transfer analysis. For these code ensembles, we show that WD of NB-SC-LDPC codes, which provides a significant decrease in latency and complexity compared to decoding across the entire parity-check matrix, results in a negligible decrease in the near-capacity performance for a sufficiently large window size W on both the BEC and the BIAWGNC. Also, we show that NB-SC-LDPC code ensembles exhibit gains in the WD threshold compared to the corresponding block code ensembles decoded across the entire parity-check matrix, and that the gains increase as the finite field size q increases. Moreover, from the viewpoint of decoding complexity, we see that (3,6)-regular NB-SC-LDPC codes are particularly attractive due to the fact that they achieve near-capacity thresholds even for small q and W.Comment: 6 pages, 8 figures; submitted to 2014 IEEE International Symposium on Information Theor

Biomolecular Functionalization of a Nanomaterial to Control Stability and Retention within Live Cells

Noncovalent hybrids of single-stranded DNA and single-walled carbon nanotubes (SWCNTs) have demonstrated applications in biomedical imaging and sensing due to their enhanced biocompatibility and photostable, environmentally responsive near-infrared (NIR) fluorescence. The fundamental properties of such DNA-SWCNTs have been studied to determine the correlative relationships between oligonucleotide sequence and length, SWCNT species, and the physical attributes of the resultant hybrids. However, intracellular environments introduce harsh conditions that can change the physical identities of the hybrid nanomaterials, thus altering their intrinsic optical properties. Here, through visible and NIR fluorescence imaging in addition to confocal Raman microscopy, we show that the oligonucleotide length controls the relative uptake, intracellular optical stability, and retention of DNA-SWCNTs in mammalian cells. Although the absolute NIR fluorescence intensity of DNA-SWCNTs in murine macrophages increases with increasing oligonucleotide length (from 12 to 60 nucleotides), we found that shorter oligonucleotide DNA-SWCNTs undergo a greater magnitude of spectral shift and are more rapidly internalized and expelled from the cell after 24 h. Furthermore, by labeling the DNA with a fluorophore that dequenches upon removal from the SWCNT surface, we found that shorter oligonucleotide strands are displaced from the SWCNT within the cell, altering the physical identity and changing the fate of the internalized nanomaterial. Finally, through a pharmacological inhibition study, we identified the mechanism of SWCNT expulsion from the cells as lysosomal exocytosis. These findings provide a fundamental understanding of the interactions between SWCNTs and live cells as well as evidence suggesting the ability to control the biological fate of the nanomaterials merely by varying the type of DNA wrapping

Rational, yet simple, design and synthesis of an antifreeze-protein inspired polymer for cellular cryopreservation

Antifreeze (glyco) proteins AF(G)Ps are potent ice recrystallization inhibitors, which is a desirable property to enhance cryopreservation of donor tissue/cells. Here we present the rational synthesis of a new, biomimetic, ice-recrystallization inhibiting polymer derived from a cheap commodity polymer, based on an ampholyte structure. The polymer is used to enhance the cryopreservation of red blood cells, demonstrating a macromolecular solution to tissue storage