164 research outputs found

    Native American children and school readiness: A nationally representative study of individual and cumulative risks

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    Using a nationally representative dataset (Early Childhood Longitudinal Study-Birth Cohort) and bioecological-cumulative disadvantage framework, the present study examined school readiness among American Indian and Alaska Native (AIAN) children. It investigated the relations between salient child and family risk experiences (i.e., poverty, preterm/low birth weight, low maternal education, single motherhood, inadequate prenatal care, teen motherhood, and severe maternal depression), and kindergarten academic (i.e., reading and math) and behavioral outcomes (i.e., social competence, approaches to learning, and externalizing behaviors). Descriptive statistics (representative of children born in 2001) revealed 58.5% of AIAN children experienced poverty at least once prior to kindergarten entry and 45% experienced two or more risks. Hierarchical linear regression examining cumulative risk counts explained less variance in all outcomes than individual risk models and were not significant for behavior outcomes. Regression models with all seven individual risks revealed that poverty exposure at any point prior to kindergarten meaningfully impacted academic skills; however, individual risks were not uniquely related to parent-reported behavioral skills. Individual risk models accounted for 12% and 13% of unique variance in reading and math, respectively. Significant moderation effects were found for behavior outcomes indicating maternal characteristics such as single motherhood, teen motherhood, and low maternal education were related to behavior only in the context of poverty. Findings suggested children who experienced poverty and had mothers without a high school diploma or who gave birth as teenagers demonstrated lower social competence and approaches to learning and higher externalizing behaviors. Interestingly, findings also revealed children of single mothers who experience poverty scored higher on approaches to learning and lower on externalizing behaviors than children with married/cohabitating parents experiencing poverty. Given the salience of specific combinations of poverty and maternal characteristics for AIAN children, implications for two-generation programming is discussed along with the potential value of extended family networks. In light of the findings regarding single mothers, more research is needed to explore the unique experiences of AIAN families in the context of their cultural networks to better understand the strengths and protective factors supporting these families en route to resilient outcomes

    Metabarcoding soil microarthropods for soil quality assessment: importance of integrated taxonomy, phylogenetic marker selection and sampling design

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    Soil microarthropods are ubiquitous and ecologically significant in terrestrial environments. Collembola and Oribatida are the two most abundant and diverse representatives of microarthropods and are commonly targeted biological indicators of soil quality. Traditional methods for studying these groups have provided taxonomic and functional data for individuals but are inefficient for large scale biomonitoring applications. The adoption of molecular methods like metabarcoding is predicted to improve the efficiency of biomonitoring microarthropods but can be limited by the availability of reference specimens in sequence databases, and the importance of barcode selection and sampling design for this approach in plot-level experiments has not been explored. Demonstrated here, the inclusion of locally derived specimen barcodes to reference libraries significantly improved the quality of metabarcoding data. Also, targeting two barcodes (18S and COI) improved microarthropod richness estimates, and 10 samples with >10 m separation between each is recommend to increase the proportion of diversity detected.Master of Science (MSc) in Biolog

    A Bacteriophage-Acquired O-Antigen Polymerase (Wzy<sub>β</sub>) from <i>P. aeruginosa </i>Serotype O16 Performs a Varied Mechanism Compared to Its Cognate Wzy<sub>α</sub>

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    Pseudomonas aeruginosa is a Gram-negative bacterium that produces highly varied lipopolysaccharide (LPS) structures. The O antigen (O-Ag) in the LPS is synthesized through the Wzx/Wzy-dependent pathway where lipid-linked O-Ag repeats are polymerized by Wzy. Horizontal-gene transfer has been associated with O-Ag diversity. The O-Ag present on the surface of serotypes O5 and O16, differ in the intra-molecular bonds, α and β, respectively; the latter arose from the action of three genes in a seroconverting unit acquired from bacteriophage D3, including a β-polymerase (Wzyβ). To further our understanding of O-polymerases, the inner membrane (IM) topology of Wzyβ was determined using a dual phoA-lacZα reporter system wherein random 3’ gene truncations were localized to specific loci with respect to the IM by normalized reporter activities as determined through the ratio of alkaline phosphate activity to β-galactosidase activity. The topology of Wzyβ developed through this approach was shown to contain two predominant periplasmic loops, PL3 (containing an RX10G motif) and PL4 (having an O-Ag ligase superfamily motif), associated with inverting glycosyltransferase reaction. Through site-directed mutagenesis and complementation assays, residues Arg254, Arg270, Arg272 and His300 were found to be essential for Wzyβ function. Additionally, like-charge substitutions, R254K and R270K, could not complement the wzyβ knockout, highlighting the essential guanidium side group of Arg residues. The O-Ag ligase domain is conserved among heterologous Wzy proteins that produce β-linked O-Ag repeat units. Taking advantage of the recently obtained whole-genome sequence of serotype O16 a candidate promoter was identified. Wzyβ under its native promoter was integrated in the PAO1 genome, which resulted in simultaneous production of α- and β-linked O-Ag. These observations established that members of Wzy-like family consistently exhibit a dual-periplasmic loops topology, and identifies motifs that are plausible to be involved in enzymatic activities. Based on these results, the phage-derived Wzyβ utilizes a different reaction mechanism in the P. aeruginosa host to avoid self-inhibition during serotype conversion

    Observing Panda Play: Implications for Zoo Programming and Conservation Efforts

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    This study explores the effects of visitor observation of giant panda play on visitor concern for endangered species and satisfaction with seeing giant pandas. A total of 335 visitors to three institutions that house giant pandas participated in the study. These institutions are: the Chengdu Research Base of Giant Panda Breeding, and the Chengdu Zoo, in China; and Zoo Atlanta in the U.S. After viewing the giant pandas, visitors were interviewed on whether they ever observed a panda play session, whether they observed panda play on the day of the visit, whether they wanted additional information on panda protection, and how satisfied they were with their visit to the pandas. An informational flyer was given to each interested survey participant after the interview. Visitors did not differ in their request for conservation information according to whether they had ever seen pandas play. However, visitors who observed panda play on the day of their visit expressed greater satisfaction with their visit. Implications for zoos and their conservation efforts are discussed

    Building Babies - Chapter 16

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    In contrast to birds, male mammals rarely help to raise the offspring. Of all mammals, only among rodents, carnivores, and primates, males are sometimes intensively engaged in providing infant care (Kleiman and Malcolm 1981). Male caretaking of infants has long been recognized in nonhuman primates (Itani 1959). Given that infant care behavior can have a positive effect on the infant’s development, growth, well-being, or survival, why are male mammals not more frequently involved in “building babies”? We begin the chapter defining a few relevant terms and introducing the theory and hypotheses that have historically addressed the evolution of paternal care. We then review empirical findings on male care among primate taxa, before focusing, in the final section, on our own work on paternal care in South American owl monkeys (Aotus spp.). We conclude the chapter with some suggestions for future studies.Deutsche Forschungsgemeinschaft (HU 1746/2-1) Wenner-Gren Foundation, the L.S.B. Leakey Foundation, the National Geographic Society, the National Science Foundation (BCS-0621020), the University of Pennsylvania Research Foundation, the Zoological Society of San Dieg

    Exploiting the archive: and the animals came in two by two, 16mm, CD-ROM and BetaSp

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    This a post-print, author-produced version of an article accepted for publication in Area. Copyright © 1999 Wiley Blackwell. The definitive version is available at www3.interscience.wiley.comUsing an account of the construction and subsequent exploitation of the film archive at the BBC's Natural History Unit, this paper explores the ways in which animals are embedded in the different cultures of care, control and commodification in the zoo and the wildlife film-making unit. Network analysis is used to account for the similarities and tensions between these forms of animal exhibition, as revealed in the electronic zoo at Wildscreen World

    Heart function and hemodynamic analysis for zebrafish embryos

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    The Zebrafish has emerged to become a powerful vertebrate animal model for cardiovascular research in recent years. Its advantages include easy genetic manipulation, transparency, small size, low cost, and the ability to survive without active circulation at early stages of development. Sequencing the whole genome and identifying ortholog genes with human genome made it possible to induce clinically relevant cardiovascular defects via genetic approaches. Heart function and disturbed hemodynamics need to be assessed in a reliable manner for these disease models in order to reveal the mechanobiology of induced defects. This effort requires precise determination of blood flow patterns as well as hemodynamic stress (i.e., wall shear stress and pressure) levels within the developing heart. While traditional approach involves time-lapse brightfield microscopy to track cell and tissue movements, in more recent studies fast light-sheet fluorescent microscopes are utilized for that purpose. Integration of more complicated techniques like particle image velocimetry and computational fluid dynamics modeling for hemodynamic analysis holds a great promise to the advancement of the Zebrafish studies. Here, we discuss the latest developments in heart function and hemodynamic analysis for Zebrafish embryos and conclude with our future perspective on dynamic analysis of the Zebrafish cardiovascular system.We would like to thank to Qatar University Biomedical Research Center team for the study; Dr. Asma Alhani, Dr. Gheeyath Nasral-lah, Ms. Sahar IsaDas, Dr. Hany Mady, Dr. Hadi Yassine, Dr. Nahla Eltai for scientific support; and Ms. Naiema Al-Meer, Ms. Maria Khalid Smatti, and Ms. Fadheela Mohammad for administrative support. This research was supported by Qatar University internal grants (QUST-BRC-SPR\2017-1 and QUUG-BRC-2017-3 to H.C.Y.).Scopu

    Cardiac Hypertrophy Involves Both Myocyte Hypertrophy and Hyperplasia in Anemic Zebrafish

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    Background: An adult zebrafish heart possesses a high capacity of regeneration. However, it has been unclear whether and how myocyte hyperplasia contributes to cardiac remodeling in response to biomechanical stress and whether myocyte hypertrophy exists in the zebrafish. To address these questions, we characterized the zebrafish mutant tr265/tr265, whose Band 3 mutation disrupts erythrocyte formation and results in anemia. Although Band 3 does not express and function in the heart, the chronic anemia imposes a sequential biomechanical stress towards the heart. Methodology/principal findings: Hearts of the tr265/tr265 Danio rerio mutant become larger than those of the sibling by week 4 post fertilization and gradually exhibit characteristics of human cardiomyopathy, such as muscular disarray, re-activated fetal gene expression, and severe arrhythmia. At the cellular level, we found both increased individual cardiomyocyte size and increased myocyte proliferation can be detected in week 4 to week 12 tr265/tr265 fish. Interestingly, all tr265/tr265 fish that survive after week-12 have many more cardiomyocytes of smaller size than those in the sibling, suggesting that myocyte hyperplasia allows the long-term survival of these fish. We also show the cardiac hypertrophy process can be recapitulated in wild-type fish using the anemia-inducing drug phenylhydrazine (PHZ). Conclusions/significance: The anemia-induced cardiac hypertrophy models reported here are the first adult zebrafish cardiac hypertrophy models characterized. Unlike mammalian models, both cardiomyocyte hypertrophy and hyperplasia contribute to the cardiac remodeling process in these models, thus allowing the effects of cardiomyocyte hyperplasia on cardiac remodeling to be studied. However, since anemia can induce effects on the heart other than biomechanical, non-anemic zebrafish cardiac hypertrophy models shall be generated and characterized
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