1,987 research outputs found

    Multiply Robust Causal Inference with Double Negative Control Adjustment for Categorical Unmeasured Confounding

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    Unmeasured confounding is a threat to causal inference in observational studies. In recent years, use of negative controls to mitigate unmeasured confounding has gained increasing recognition and popularity. Negative controls have a longstanding tradition in laboratory sciences and epidemiology to rule out non-causal explanations, although they have been used primarily for bias detection. Recently, Miao et al. (2018) have described sufficient conditions under which a pair of negative control exposure and outcome variables can be used to nonparametrically identify the average treatment effect (ATE) from observational data subject to uncontrolled confounding. In this paper, we establish nonparametric identification of the ATE under weaker conditions in the case of categorical unmeasured confounding and negative control variables. We also provide a general semiparametric framework for obtaining inferences about the ATE while leveraging information about a possibly large number of measured covariates. In particular, we derive the semiparametric efficiency bound in the nonparametric model, and we propose multiply robust and locally efficient estimators when nonparametric estimation may not be feasible. We assess the finite sample performance of our methods in extensive simulation studies. Finally, we illustrate our methods with an application to the postlicensure surveillance of vaccine safety among children

    Journeying : young children’s responses to picture books of traumatic and sensitive issues

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    This study investigates the response of a class of 35 seven and eight year old children to ten picture books with difficult, traumatic subject matter. Two of the stories deal with areas of emotional loss, including the death of a grandfather; five stories take the area of the Holocaust as their central theme, and three are stories of earthquakes, with the consequent loss of life and destruction. My research findings contribute to the study of children’s literature in education by uniquely analysing and giving insight into especially young children’s responses to this particular genre of children’s literature. In this research programme, the children are invited to engage in reading and four designed activities emerged for response: the central importance of spoken language, the place of writing to capture meaning and significance, the value of drawing to enhance understanding and the place of imaginative role play as children worked on their impressions of events in the stories. My central research questions are: What is young children’s understanding of and response to texts and pictures in selected children’s picture books of trauma? In what ways might young children’s responses to these issues and their accompanying activities reshape their critical thinking? What have I, as the researcher, learnt about my role as a teacher through teaching traumatic issues? The study was conducted in Taiwan using participatory action research methods. My evidence shows that these children are capable of understanding complex and disturbing situations that underpin the picture book narratives. They used their social, interactive, verbal, emotional and imaginative skills to respond to the texts in powerful ways. The significance of the teacher’s role as a listener, questioner and learner was crucial in helping to motive and engage the children. The study’s findings are that picture books that deal with disturbing human issues can be introduced as part of a planned programme of Arts and Life education in Grades 1 to 6 of the primary school curriculum and that children as young as seven are capable of responding to them with maturity and sophistication

    Journeying : young children’s responses to picture books of traumatic and sensitive issues

    Get PDF
    This study investigates the response of a class of 35 seven and eight year old children to ten picture books with difficult, traumatic subject matter. Two of the stories deal with areas of emotional loss, including the death of a grandfather; five stories take the area of the Holocaust as their central theme, and three are stories of earthquakes, with the consequent loss of life and destruction. My research findings contribute to the study of children’s literature in education by uniquely analysing and giving insight into especially young children’s responses to this particular genre of children’s literature. In this research programme, the children are invited to engage in reading and four designed activities emerged for response: the central importance of spoken language, the place of writing to capture meaning and significance, the value of drawing to enhance understanding and the place of imaginative role play as children worked on their impressions of events in the stories. My central research questions are: What is young children’s understanding of and response to texts and pictures in selected children’s picture books of trauma? In what ways might young children’s responses to these issues and their accompanying activities reshape their critical thinking? What have I, as the researcher, learnt about my role as a teacher through teaching traumatic issues? The study was conducted in Taiwan using participatory action research methods. My evidence shows that these children are capable of understanding complex and disturbing situations that underpin the picture book narratives. They used their social, interactive, verbal, emotional and imaginative skills to respond to the texts in powerful ways. The significance of the teacher’s role as a listener, questioner and learner was crucial in helping to motive and engage the children. The study’s findings are that picture books that deal with disturbing human issues can be introduced as part of a planned programme of Arts and Life education in Grades 1 to 6 of the primary school curriculum and that children as young as seven are capable of responding to them with maturity and sophistication.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Common DNA methylation dynamics in endometriod adenocarcinoma and glioblastoma suggest universal epigenomic alterations in tumorigenesis

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    Trends in altered DNA methylation have been defined across human cancers, revealing global loss of methylation (hypomethylation) and focal gain of methylation (hypermethylation) as frequent cancer hallmarks. Although many cancers share these trends, little is known about the specific differences in DNA methylation changes across cancer types, particularly outside of promoters. Here, we present a comprehensive comparison of DNA methylation changes between two distinct cancers, endometrioid adenocarcinoma (EAC) and glioblastoma multiforme (GBM), to elucidate common rules of methylation dysregulation and changes unique to cancers derived from specific cells. Both cancers exhibit significant changes in methylation over regulatory elements. Notably, hypermethylated enhancers within EAC samples contain several transcription factor binding site clusters with enriched disease ontology terms highlighting uterine function, while hypermethylated enhancers in GBM are found to overlap active enhancer marks in adult brain. These findings suggest that loss of original cellular identity may be a shared step in tumorigenesis

    Functional factor VIII made with von Willebrand factor at high levels in transgenic milk

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    Background—Current manufacturing methods for recombinant human Factor VIII (rFVIII) within mammalian cell cultures are inefficient which limit the abundance needed for affordable, worldwide treatment of hemophilia A. However, rFVIII has been expressed at very high levels by the transgenic mammary gland of mice, rabbits, sheep and pigs. Unfortunately, it is secreted into milk with low specific activity due in part to the labile, heterodimeric structure that results from furin processing of its B domain. Objectives—To express biologically active rFVIII in the milk of transgenic mice through targeted bioengineering. Methods—Transgenic mice were made with a mammary specific FVIII gene (226/N6) bioengineered for efficient expression and stability containing a B domain with no furin cleavage sites. 226/N6 was expressed with and without von Willebrand Factor (VWF). 226/N6 was evaluated by ELISA, SDS-PAGE, Western blot, and one- and two-stage clotting assays. Hemostatic activity of immunoaffinity enriched 226/N6 was studied in vivo by infusion into hemophilia A knockout mice. Results and conclusions—With or without co-expression of VWF, 226/N6 was secreted into milk as a biologically active single chain molecule that retained high specific activity similar to therapeutic-grade FVIII. 226/N6 had \u3e450-fold higher IU/ml than previously reported in cell culture for rFVIII. 226/N6 exhibited similar binding to plasma-derived VWF as therapeutic-grade rFVIII and intravenous infusion of transgenic 226/N6 corrected the bleeding phenotype of hemophilia A mice. This provides proof-of-principle to study expression of 226/N6 and perhaps other single chain bioengineered rFVIII in the milk of transgenic livestock

    Multi-color Cavity Metrology

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    Long baseline laser interferometers used for gravitational wave detection have proven to be very complicated to control. In order to have sufficient sensitivity to astrophysical gravitational waves, a set of multiple coupled optical cavities comprising the interferometer must be brought into resonance with the laser field. A set of multi-input, multi-output servos then lock these cavities into place via feedback control. This procedure, known as lock acquisition, has proven to be a vexing problem and has reduced greatly the reliability and duty factor of the past generation of laser interferometers. In this article, we describe a technique for bringing the interferometer from an uncontrolled state into resonance by using harmonically related external fields to provide a deterministic hierarchical control. This technique reduces the effect of the external seismic disturbances by four orders of magnitude and promises to greatly enhance the stability and reliability of the current generation of gravitational wave detector. The possibility for using multi-color techniques to overcome current quantum and thermal noise limits is also discussed

    Functional Mutation of Multiple Solvent-Exposed Loops in the Ecballium elaterium Trypsin Inhibitor-II Cystine Knot Miniprotein

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    The Ecballium elaterium trypsin inhibitor (EETI-II), a 28-amino acid member of the knottin family of peptides, contains three interwoven disulfide bonds that form multiple solvent-exposed loops. Previously, the trypsin binding loop of EETI-II has been engineered to confer binding to several alternative molecular targets. Here, EETI-II was further explored as a molecular scaffold for polypeptide engineering by evaluating the ability to mutate two of its structurally adjacent loops.Yeast surface display was used to engineer an EETI-II mutant containing two separate integrin binding epitopes. The resulting knottin peptide was comprised of 38 amino acids, and contained 11- and 10-residue loops compared to wild-type EETI-II, which naturally contains 6- and 5-residue loops, respectively. This knottin peptide bound to α(v)β(3) and α(v)β(5) integrins with affinities in the low nanomolar range, but bound weakly to the related integrins α(5)β(1) and α(iib)β(3). In addition, the engineered knottin peptide inhibited tumor cell adhesion to vitronectin, an extracellular matrix protein that binds to α(v)β(3) and α(v)β(5) integrins. A (64)Cu radiolabeled version of this knottin peptide demonstrated moderate serum stability and excellent tumor-to-muscle and tumor-to-blood ratios by positron emission tomography imaging in human tumor xenograft models. Tumor uptake was ∼3-5% injected dose per gram (%ID/g) at one hour post injection, with rapid clearance of probe through the kidneys.We demonstrated that multiple loops of EETI-II can be mutated to bind with high affinity to tumor-associated integrin receptors. The resulting knottin peptide contained 21 (>50%) non-native amino acids within two mutated loops, indicating that extended loop lengths and sequence diversity were well tolerated within the EETI-II scaffold. A radiolabeled version of this knottin peptide showed promise for non-invasive imaging of integrin expression in living subjects. However, reduced serum and metabolic stability were observed compared to an engineered integrin-binding EETI-II knottin peptide containing only one mutated loop

    ADDRESSING LITERACY RATES AMONG STUDENTS IN GRADES 3-5 WHO ARE ELIGIBLE FOR FREE AND REDUCED LUNCH IN DURHAM COUNTY THROUGH THE READ AND FEED PROGRAM

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    Improving literacy among children in Durham County warrants immediate public health action. On a national, state, and county level, research shows that students who are eligible for free and reduced lunch through the National School Lunch Program (NSLP) show significantly lower reading proficiency compared to students who are not eligible. Children with low literacy rates have a higher risk of dropping out of school, not attending university, and having lower job prospects compared to their peers that read at a higher literacy level. Taking this data into consideration, we plan to implement a nutrition-supported literacy-based initiative within Durham County Public Schools. The Read and Feed program will serve students in grades 3, 4, and 5 who read at a “not-proficient” literacy level and are enrolled in NSLP. The program’s mission is to impact under-served elementary students by strengthening their reading skills and providing nutritious meals. Keywords: literacy, nutrition, food insecurity, free and reduced lunch, NSLP, elementary students, Durham County, North CarolinaMaster of Public Healt
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