40 research outputs found

    Examining the Effect of Maternal Obesity on Vitamin D Metabolism in the Placenta

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    In the United States and in many other developed countries, obesity is becoming an increasingly widespread problem due to several factors including poor nutrition and sedentary lifestyles. Previous studies have shown obese people to have less circulating vitamin D than lean people and this study aimed to determine whether obese mothers pass less vitamin D through their placenta to their offspring than lean mothers do and whether vitamin D deficiency resulting in fewer vitamin D receptors in the placenta can be reversed by treatment of placental cells with the active and inactive forms of vitamin D. The data collected from this study show that placentas from obese mothers have less vitamin D receptors than placentas from lean mothers and that placental cells treated with the active form of vitamin D show increased expression of vitamin D receptors. Preliminary tests of mitochondrial respiration have found that placental cells from an obese mother respond more dramatically in terms of oxygen consumption rate to treatment with both the active and inactive forms of vitamin D than placental cells from a lean mother do. Vitamin D plays an important role in the placenta, and future studies should be conducted to determine the daily dosage of vitamin D necessary to reverse vitamin D deficiency during pregnancy

    Student exam analysis (debriefing) promotes positive changes in exam preparation and learning

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    Traditional exam review sessions, typically conducted orally and in class by the instructor, are intended to identify the most frequently missed or problematic question with the intent of helping students perform better on subsequent exams. The shortcoming of this instructor- led activity is that it tends to focus on issues with content or understanding rather than helping the individual student prevent or avoid similar mistakes on future exams. Here, we report that students who performed a more comprehensive out-of-class exam debrief after the first exam significantly improve their exam performance compared with students that did not conduct the exam debrief. We also identify the most common mistakes that students make on exams and the most frequent self-selected strategies to improve their learning. By having students focus on missed questions coupled with addressing deficiencies in their test preparation strategies and behaviors, they likely engage in more self-regulated learning to better prepare for exams and avoid repeating past mistakes

    Student exam analysis (debriefing) promotes positive changes in exam preparation and learning

    Get PDF
    Traditional exam review sessions, typically conducted orally and in class by the instructor, are intended to identify the most frequently missed or problematic question with the intent of helping students perform better on subsequent exams. The shortcoming of this instructor-led activity is that it tends to focus on issues with content or understanding rather than helping the individual student prevent or avoid similar mistakes on future exams. Here, we report that students who performed a more comprehensive out-of-class exam debrief after the first exam significantly improve their exam performance compared with students that did not conduct the exam debrief. We also identify the most common mistakes that students make on exams and the most frequent self-selected strategies to improve their learning. By having students focus on missed questions coupled with addressing deficiencies in their test preparation strategies and behaviors, they likely engage in more self-regulated learning to better prepare for exams and avoid repeating past mistakes

    Mechanical design of the optical modules intended for IceCube-Gen2

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    IceCube-Gen2 is an expansion of the IceCube neutrino observatory at the South Pole that aims to increase the sensitivity to high-energy neutrinos by an order of magnitude. To this end, about 10,000 new optical modules will be installed, instrumenting a fiducial volume of about 8 km3. Two newly developed optical module types increase IceCube’s current sensitivity per module by a factor of three by integrating 16 and 18 newly developed four-inch PMTs in specially designed 12.5-inch diameter pressure vessels. Both designs use conical silicone gel pads to optically couple the PMTs to the pressure vessel to increase photon collection efficiency. The outside portion of gel pads are pre-cast onto each PMT prior to integration, while the interiors are filled and cast after the PMT assemblies are installed in the pressure vessel via a pushing mechanism. This paper presents both the mechanical design, as well as the performance of prototype modules at high pressure (70 MPa) and low temperature (−40∘C), characteristic of the environment inside the South Pole ice

    The next generation neutrino telescope: IceCube-Gen2

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    The IceCube Neutrino Observatory, a cubic-kilometer-scale neutrino detector at the geographic South Pole, has reached a number of milestones in the field of neutrino astrophysics: the discovery of a high-energy astrophysical neutrino flux, the temporal and directional correlation of neutrinos with a flaring blazar, and a steady emission of neutrinos from the direction of an active galaxy of a Seyfert II type and the Milky Way. The next generation neutrino telescope, IceCube-Gen2, currently under development, will consist of three essential components: an array of about 10,000 optical sensors, embedded within approximately 8 cubic kilometers of ice, for detecting neutrinos with energies of TeV and above, with a sensitivity five times greater than that of IceCube; a surface array with scintillation panels and radio antennas targeting air showers; and buried radio antennas distributed over an area of more than 400 square kilometers to significantly enhance the sensitivity of detecting neutrino sources beyond EeV. This contribution describes the design and status of IceCube-Gen2 and discusses the expected sensitivity from the simulations of the optical, surface, and radio components

    Sensitivity of IceCube-Gen2 to measure flavor composition of Astrophysical neutrinos

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    The observation of an astrophysical neutrino flux in IceCube and its detection capability to separate between the different neutrino flavors has led IceCube to constraint the flavor content of this flux. IceCube-Gen2 is the planned extension of the current IceCube detector, which will be about 8 times larger than the current instrumented volume. In this work, we study the sensitivity of IceCube-Gen2 to the astrophysical neutrino flavor composition and investigate its tau neutrino identification capabilities. We apply the IceCube analysis on a simulated IceCube-Gen2 dataset that mimics the High Energy Starting Event (HESE) classification. Reconstructions are performed using sensors that have 3 times higher quantum efficiency and isotropic angular acceptance compared to the current IceCube optical modules. We present the projected sensitivity for 10 years of data on constraining the flavor ratio of the astrophysical neutrino flux at Earth by IceCube-Gen2

    Direction reconstruction performance for IceCube-Gen2 Radio

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    The IceCube-Gen2 facility will extend the energy range of IceCube to ultra-high energies. The key component to detect neutrinos with energies above 10 PeV is a large array of in-ice radio detectors. In previous work, direction reconstruction algorithms using the forward-folding technique have been developed for both shallow (≲20 m) and deep in-ice detectors, and have also been successfully used to reconstruct cosmic rays with ARIANNA. Here, we focus on the reconstruction algorithm for the deep in-ice detector, which was recently introduced in the context of the Radio Neutrino Observatory in Greenland (RNO-G)

    Estimating the coincidence rate between the optical and radio array of IceCube-Gen2

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    The IceCube-Gen2 Neutrino Observatory is proposed to extend the all-flavour energy range of IceCube beyond PeV energies. It will comprise two key components: I) An enlarged 8km3 in-ice optical Cherenkov array to measure the continuation of the IceCube astrophysical neutrino flux and improve IceCube\u27s point source sensitivity above ∼100TeV; and II) A very large in-ice radio array with a surface area of about 500km2. Radio waves propagate through ice with a kilometer-long attenuation length, hence a sparse radio array allows us to instrument a huge volume of ice to achieve a sufficient sensitivity to detect neutrinos with energies above tens of PeV. The different signal topologies for neutrino-induced events measured by the optical and in-ice radio detector - the radio detector is mostly sensitive to the cascades produced in the neutrino interaction, while the optical detector can detect long-ranging muon and tau leptons with high accuracy - yield highly complementary information. When detected in coincidence, these signals will allow us to reconstruct the neutrino energy and arrival direction with high fidelity. Furthermore, if events are detected in coincidence with a sufficient rate, they resemble the unique opportunity to study systematic uncertainties and to cross-calibrate both detector components

    Deep Learning Based Event Reconstruction for the IceCube-Gen2 Radio Detector

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    The planned in-ice radio array of IceCube-Gen2 at the South Pole will provide unprecedented sensitivity to ultra-high-energy (UHE) neutrinos in the EeV range. The ability of the detector to measure the neutrino’s energy and direction is of crucial importance. This contribution presents an end-to-end reconstruction of both of these quantities for both detector components of the hybrid radio array (\u27shallow\u27 and \u27deep\u27) using deep neural networks (DNNs). We are able to predict the neutrino\u27s direction and energy precisely for all event topologies, including the electron neutrino charged-current (νe-CC) interactions, which are more complex due to the LPM effect. This highlights the advantages of DNNs for modeling the complex correlations in radio detector data, thereby enabling a measurement of the neutrino energy and direction. We discuss how we can use normalizing flows to predict the PDF for each individual event which allows modeling the complex non-Gaussian uncertainty contours of the reconstructed neutrino direction. Finally, we discuss how this work can be used to further optimize the detector layout to improve its reconstruction performance
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