Investigation of Nutritional Biomarkers Associated with Metabolism of Inorganic Arsenic and Infant Birthweight

Exposure to inorganic arsenic (As) in utero represents a critical window of susceptibility for iAs associated adverse birth outcomes. Ingested iAs undergoes hepatic methylation generating mono- and di-methyl arsenicals (MMA and DMA, respectively), a process that facilitates urinary As elimination. Differences in pregnant women’s metabolism of As (e.g. increases in %MMAs and decreases in %DMAs) are a risk factor for adverse birth outcomes. One carbon metabolism (OCM), the nutritionally-regulated pathway essential for supplying methyl groups, plays a role in As metabolism and is understudied during the prenatal period. In this cross-sectional study from the Biomarkers of Exposure to ARsenic (BEAR) pregnancy cohort in Gómez Palacio, Mexico, we assessed the relationships among OCM indicators (e.g. maternal biomarkers of serum B12, folate, and homocysteine (Hcys)), and levels of iAs and its metabolites in maternal urine and in neonatal serum. We also estimated the relationship between OCM indicators, iAs metabolism, and infant birthweight using a causal mediation approach, where we measured the total effect (TE) and the natural direct effects (NDE) of OCM indicators on infant birthweight, and controlled direct effects (CDE) of both OCM indicators and maternal metabolism of iAs on infant birthweight. Interestingly, the prevalence of folate sufficiency (serum folate levels > 9 nmol/L) in the cohort was high 99%, and hyperhomocysteinemia (Hcys levels >10.4 μmol/L) was low (8%). However, 74% of the women displayed a deficiency in B12 (serum levels < 148 pmol/L). Differences in lower B12 levels and higher Hcys were associated with increases in total arsenic levels in urine (U-tAs). In unadjusted comparisons, infants born to mothers in the lowest tertile of serum folate had significantly higher mean levels of C-%MMA relative to folate replete women. Furthermore, beta regression results demonstrated that maternal Hcys was positively associated with both C-tAs and %C-MMAs. Interestingly, levels of folate modify the effects of B12 deficiency on infant birthweight. The causal mediation results demonstrated that there is evidence of interaction between OCM indicators and iAs metabolism. The results from this study indicate that maternal OCM status may influence neonatal As metabolites, and interactions of OCM with iAs metabolism may influence infant birthweight.Doctor of Philosoph

“Let Our Freak Flags Fly”: Shrek the Musical and the Branding of Diversity

This is the publisher's version, also available electronically from http://muse.jhu.edu/journals/theatre_journal/v062/62.2.brater.html“’Let Our Freak Flags Fly’: Shrek the Musical and the Branding of Diversity” argues that DreamWorks used Shrek the Musical to exploit a generic theme of multiculturalism to extend the reach of the Shrek franchise and challenge Disney’s domination of the Broadway market. By bringing a political-economic analysis to bear on the study of commercial theatre, the essay shows that DreamWorks’s marketing strategy—diversification—provided the theme—diversity—for the product it was employing to implement that strategy. Yet because Shrek’s multicultural message is contradicted by the blatant racial stereotyping of Donkey, Shrek’s “jive-spouting sidekick,” the musical in fact epitomizes the contradictions that inform multiculturalism in the early twenty-first-century marketplace and functions as an unlikely emblem of the Age of Obam

Razonamiento de los estudiantes acerca de la probabilidad en el contexto de una rifa

III Congreso Internacional Virtual de Educación Estadística (CIVEEST), 21-24 febrero de 2019. [www.ugr.es/local/fqm126/civeest.html]Assessing students’ conceptions related to independence and probability has been the focus of research in probability education for over 40 years. While we know a lot from past studies about predictable ways students may reason with well-known tasks, developing a diagnostic assessment that can be used by teachers to inform instruction demands the use of familiar and unfamiliar contexts. This paper presents the current work of a research team whose aim is to create a valid formative assessment that uses a psychometric model to confidently predict the presence of a misconception or conception across many items. The focus in this paper is on the evolution of one item and the difficulty it presents in accurately diagnosing students’ conceptions of independence.La evaluación de las concepciones de los estudiantes relacionadas con la independencia y la probabilidad ha sido el foco de la investigación en la enseñanza de la probabilidad por más de 40 años. Si bien sabemos mucho de los últimos estudios sobre las maneras predecibles en que pueden razonar los estudiantes con tareas bien conocidas, desarrollar una evaluación de diagnóstico que pueda ser utilizada por los maestros para informar la instrucción exige el uso de contextos familiares y desconocidos. Este documento presenta el trabajo actual de un equipo de investigación cuyo objetivo es crear una evaluación formativa válida que utiliza un modelo psicométrico que permita predecir con confianza la presencia de una concepción errónea a través de muchos ítems. En el presente trabajo trata de la evolución de un ítem y la dificultad que presenta para el diagnóstico con precisión de las concepciones de los estudiantes sobre la independencia

Phases of collaborative mathematical problem solving and joint attention : a case study utilizing mobile gaze tracking

Given the recent development of mobile gaze-tracking devices it has become possible to view and interpret what the student sees and unravel the associated problem-solving processes further. It has also become possible to pinpoint joint attention occurrences that are fundamental for learning. In this study, we examined joint attention in collaborative mathematical problem solving. We studied the thought processes of four 15-16-year-old students in their regular classroom, using mobile gaze tracking, video and audio recordings, and smartpens. The four students worked as a group to find the shortest path to connect the vertices of a square. Combining information on the student gaze targets with a qualitative interpretation of the context, we identified the occurrences of joint attention, out of which 49 were joint visual attention occurrences and 28 were attention to different representations of the same mathematical idea. We call this joint representational attention. We discovered that 'verifying' (43%) and 'watching and listening' (35%) were the most common phases during joint attention. The most frequently occurring problem solving phases right after joint attention were also 'verifying' (47%) and 'watching and listening' (34%). We detected phase cycles commonly found in individual problem-solving processes ('planning and exploring', 'implementing', and 'verifying') outside of joint attention. We also detected phase shifts between 'verifying', 'watching and listening', and 'understanding' a problem, often occurring during joint attention. Therefore, these phases can be seen as a signal of successful interaction and the promotion of collaboration.Peer reviewe

Advancing video research methodology to capture the processes of social interaction and multimodality

In this reflective methodological paper we focus on affordances and challenges of video data. We compare and analyze two research settings that use the latest video technology to capture classroom interactions in mathematics education, namely, The Social Unit of Learning (SUL) project of the University of Melbourne and the MathTrack project of the University of Helsinki. While using these two settings as examples, we have structured our reflections around themes pertinent to video research in general, namely, research methods, data management, and research ethics. SUL and MathTrack share an understanding of mathematics learning as social multimodal practice, and provide possibilities for zooming into the situational micro interactions that construct collaborative problem-solving learning. Both settings provide rich data for in-depth analyses of peer interactions and learning processes. The settings share special needs for technical support and data management, as well as attention to ethical aspects from the perspective of the participants' security and discretion. SUL data are especially suitable for investigating interactions on a broad scope, addressing how multiple interactional processes intertwine. MathTrack, on the other hand, enables exploration of participants' visual attention in detail and its role in learning. Both settings could provide tools for teachers' professional development by showing them aspects of classroom interactions that would otherwise remain hidden.Peer reviewe

Clinical presentation of simple and combined or syndromic arteriovenous malformations.

OBJECTIVES Arteriovenous malformations of the lower extremities (AVMLE) can present as simple or complex combined or syndromic forms (e.g. Parkes Weber Syndrome). We aimed to characterize the differences in clinical presentation and natural history of these potentially life and limb threatening congenital vascular malformations. METHODS We conducted a retrospective analysis of a consecutive series of patients with AVMLE, who presented to a tertiary referral center in Switzerland between 2008 and 2018. Clinical baseline characteristics, D-dimer level and course were summarized and differences between simple, non-syndromic and combined or syndromic AVMLE determined. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression models. RESULTS Overall, 506 patients were prospectively enrolled in the Bernese Congenital Vascular Malformation Registry, 31 (6%) with AVMLE. There were 16 women and 15 men with a mean age of 18 years at first diagnosis (1 month - 72 years). Simple AVMLE was present in 22 (71%), combined or syndromic AVMLE with limb overgrowth in 9 patients (29%), respectively. Common symptoms and signs were pain 25 (81%), swelling 21 (68%) and soft tissue hypertrophy 13 (42%). Among combined or syndromic patients, 3 patients died from wound infection with sepsis or disseminated intravascular coagulation with bleeding complications (intracranial hemorrhage and bleeding from extensive leg ulcers). Combined or syndromic patients presented more often with bleeding (67% vs. 5%; p<0.001), malformation related infection (44% vs. 5%; p=0,017) and leg length difference (56% vs. 14%; p=0.049). D-dimer levels were elevated (mean 17256 μg/L, range 1557 μg/L to 80000 μg/L) and angiographic appearance showed complex, mixed type of AVMs, including interstitial type IV, in all patients with combined or syndromic AVMLE. CONCLUSION Patients with congenital simple AVMLE most often present with benign clinical features and rarely complications related to hemodynamic changes. Patients with combined or syndromic AVMLE often face serious outcomesdominated by complications other than direct high flow related heart failure

Calibration trending in the Spitzer beyond era

The Spitzer Space Telescope currently operates in the "Beyond Era", over nine years past an original cryogenic mission. As the astronomy community continues to advance scientific boundaries and push beyond original specifications, the stability of the Infrared Array Camera (IRAC) instrument is paramount. The Instrument Team (IST) monitors the pointing accuracy, temperature, and calibration and provides the information in a timely manner to observers. The IRAC IST created a calibration trending web page, available to the general astronomy community, where the team posts updates of three most pertinent scientific stability measures of the IRAC data: calibration, bias, and bad pixels. In addition, photometry and telescope properties from all the staring observations (>1500 as of April 2018) are trended to examine correlations with changes in the age or thermal properties of the telescope. A long, well-sampled baseline established by consistent monitoring outside anomalies and space weather events allows even the smallest changes to be detected

Intra-pixel gain variations and high-precision photometry with the Infrared Array Camera (IRAC)

The Infrared Array Camera (IRAC) on the Spitzer Space Telescope has been used to measure < 10^(-4) temporal variations in point sources (such as transiting extrasolar planets) at 3.6 and 4.5 μm. Due to the under-sampled nature of the PSF, the warm IRAC arrays show variations of as much as 8% in sensitivity as the center of the PSF moves across a pixel due to normal spacecraft pointing wobble and drift. These intra-pixel gain variations are the largest source of correlated noise in IRAC photometry. Usually this effect is removed by fitting a model to the science data themselves (self-calibration), which could result in the removal of astrophysically interesting signals. We describe a new technique for significantly reducing the gain variations and improving photometric precision in a given observation, without using the data to be corrected. This comprises: (1) an adaptive centroiding and repositioning method ("Peak-Up") that uses the Spitzer Pointing Control Reference Sensor (PCRS) to repeatedly position a target to within 0.1 IRAC pixels of an area of minimal gain variation; and (2) the high-precision, high-resolution measurement of the pixel gain structure using non-variable stars. We show that the technique currently allows the reduction of correlated noise by almost an order of magnitude over raw data, which is comparable to the improvement due to self-calibration. We discuss other possible sources of correlated noise, and proposals for reducing their impact on photometric precision

Spitzer/IRAC precision photometry: a machine learning approach

The largest source of noise in exoplanet and brown dwarf photometric time series made with Spitzer/IRAC is the coupling between intra-pixel gain variations and spacecraft pointing fluctuations. Observers typically correct for this systematic in science data by deriving an instrumental noise model simultaneously with the astrophysical light curve and removing the noise model. Such techniques for self-calibrating Spitzer photometric datasets have been extremely successful, and in many cases enabled near-photon-limited precision on exoplanet transit and eclipse depths. Self-calibration, however, can suffer from certain limitations: (1) temporal astrophysical signals can become aliased as part of the instrument model; (2) for some techniques adequate model estimation often requires a high degree of intra-pixel positional redundancy (multiple samples with nearby centroids) over long time spans; (3) many techniques do not account for sporadic high frequency telescope vibrations that smear out the point spread function. We have begun to build independent general-purpose intra-pixel systematics removal algorithms using three machine learning techniques: K-Nearest Neighbors (with kernel regression), Random Decision Forests, and Artificial Neural Networks. These methods remove many of the limitations of self-calibration: (1) they operate on a dedicated calibration database of approximately one million measurements per IRAC waveband (3.6 and 4.5 microns) of non-variable stars, and thus are independent of the time series science data to be corrected; (2) the database covers a large area of the "Sweet Spot, so the methods do not require positional redundancy in the science data; (3) machine learning techniques in general allow for flexibility in training with multiple, sometimes unorthodox, variables, including those that trace PSF smear. We focus in this report on the K-Nearest Neighbors with Kernel Regression technique. (Additional communications are in preparation describing Decision Forests and Neural Networks.

Modifications to the warm Spitzer data reduction pipeline

The Spitzer Space Telescope Infrared Array Camera (IRAC) basic calibrated data reduction pipeline is designed to take a single raw frame from a single IRAC detector and produce a flux-calibrated image that has had all well-understood instrumental signatures removed. We discuss several modifications to the pipeline developed in the last two years in response to the Spitzer warm mission. Due to the different instrument characteristics in the warm mission, we have significantly changed pipeline procedures for masking residual images and mitigating column pulldown. In addition, the muxbleed correction was turned off, because it is not present in the warm data. Parameters relevant to linearity correction, bad pixels, and the photometric calibration have been updated and are continually monitored