Understanding the Transition between High School and College Mathematics and Science

Mathematics and science education is gaining increasing recognition as key for the well-being of individuals and society. Accordingly, the transition from high school to college is particularly important to ensure that students are prepared for college mathematics and science. The goal of this study was to understand how high school mathematics and science course-taking related to performance in college. Specifically, the study employed a nonparametric regression method to examine the relationship between high school mathematics and science courses, and academic performance in college mathematics and science courses. The results provide some evidence pertaining to the positive benefits from high school course-taking. Namely, students who completed high school trigonometry and lab-based chemistry tended to earn higher grades in college algebra and general chemistry, respectively. However, there was also evidence that high school coursework in biology and physics did not improve course performance in general biology and college physics beyond standardized test scores. Interestingly, students who completed high school calculus earned better grades in general biology. The implications of the findings are discussed for high school curriculum and alignment in standards between high schools and colleges

Analysis of strategies for improving uranium utilization in pressurized water reactors

Systematic procedures have been devised and applied to evaluate core design and fuel management strategies for improving uranium utilization in Pressurized Water Reactors operated on a once-through fuel cycle. A principal objective has been the evaluation of suggested improvements on a self-consistent basis, allowing for concurrent changes in dependent variables such as core leakage and batch power histories, which might otherwise obscure the sometimes subtle effects of interest. Two levels of evaluation have been devised: a simple but accurate analytic model based on the observed linear variations in assembly reactivity as a function of burnup; and a numerical approach, embodied in a computer program, which relaxes this assumption and combines it with empirical prescriptions for assembly (or batch) power as a function of reactivity, and core leakage as a function of peripheral assembly power. State-of-the-art physics methods, such as PDQ-7, were used to verify and supplement these techniques.These methods have been applied to evaluate several suggested improvements: (1) axial blankets of low-enriched or depleted uranium, and of beryllium metal, (2) radial natural uranium blankets, (3) lowleakage radial fuel management, (4) high burnup fuels, (5) optimized H/U atom ratio, (6) annular fuel, and (7) mechanical spectral shift (i.e. variable fuel-to-moderator ratio) concepts such as those involving pin pulling and bundle reconstitution.The potential savings in uranium requirements compared to current practice were found to be as follows: (1) O0-3%, (2) negative, (3) 2-3%; possibly 5%, (4) "15%, (5) 0-2.5%, (6) no inherent advantage, (7) 10%. Total savings should not be assumed to be additive; and thermal/hydraulic or mechanical design restrictions may preclude full realization of some of the potential improvements

Analysis of strategies for improving uranium utilization in pressurized water reactors

Includes bibliographical references (pages 238-241)Systematic procedures have been devised and applied to evaluate core design and fuel management strategies for improving uranium utilization in Pressurized Water Reactors operated on a once-through fuel cycle. A principal objective has been the evaluation of suggested improvements on a self-consistent basis, allowing for concurrent changes in dependent variables such as core leakage and batch power histories, which might otherwise obscure the sometimes subtle effects of interest. Two levels of evaluation have been devised: a simple but accurate analytic model based on the observed linear variations in assembly reactivity as a function of burnup; and a numerical approach, embodied in a computer program, which relaxes this assumption and combines it with empirical prescriptions for assembly (or batch) power as a function of reactivity, and core leakage as a function of peripheral assembly power. State-of-the-art physics methods, such as PDQ-7, were used ! to verify and supplement these techniques.These methods have been applied to evaluate several suggested improvements: (1) axial blankets of low-enriched or depleted uranium, and of beryllium metal, (2) radial natural uranium blankets, (3) low-leakage radial fuel management, (4) high burnup fuels, (5) optimized H/U atom ratio, (6) annular fuel, and (7) mechanical spectral shift (i.e. variable fuel-to-moderator ratio) concepts such as those involving pin pulling and bundle reconstitution.The potential savings in uranium requirements compared to current practice were found to be as follows: (1) O0-3%, (2) negative, (3) 2-3%; possibly 5%, (4) "15%, (5) 0-2.5%, (6) no inherent advantage, (7) 10%. Total savings should not be assumed to be additive; and thermal/hydraulic or mechanical design restrictions may preclude full realization of some of the potential improvements

Immunolocalization of KATP channel subunits in mouse and rat cardiac myocytes and the coronary vasculature.

BACKGROUND: Electrophysiological data suggest that cardiac KATP channels consist of Kir6.2 and SUR2A subunits, but the distribution of these (and other KATP channel subunits) is poorly defined. We examined the localization of each of the KATP channel subunits in the mouse and rat heart. RESULTS: Immunohistochemistry of cardiac cryosections demonstrate Kir6.1 protein to be expressed in ventricular myocytes, as well as in the smooth muscle and endothelial cells of coronary resistance vessels. Endothelial capillaries also stained positive for Kir6.1 protein. Kir6.2 protein expression was found predominantly in ventricular myocytes and also in endothelial cells, but not in smooth muscle cells. SUR1 subunits are strongly expressed at the sarcolemmal surface of ventricular myocytes (but not in the coronary vasculature), whereas SUR2 protein was found to be localized predominantly in cardiac myocytes and coronary vessels (mostly in smaller vessels). Immunocytochemistry of isolated ventricular myocytes shows co-localization of Kir6.2 and SUR2 proteins in a striated sarcomeric pattern, suggesting t-tubular expression of these proteins. Both Kir6.1 and SUR1 subunits were found to express strongly at the sarcolemma. The role(s) of these subunits in cardiomyocytes remain to be defined and may require a reassessment of the molecular nature of ventricular KATP channels. CONCLUSIONS: Collectively, our data demonstrate unique cellular and subcellular KATP channel subunit expression patterns in the heart. These results suggest distinct roles for KATP channel subunits in diverse cardiac structures

Demonstration of methods for analytical measurement of natural circulation flow in EBR-II

Statement of responsibility on title page reads: R. J. Witt and J. E. Meyer, Includes MIT technical contributions from J. I. Choi, D. D. Lanning, J. E. Meyer, A. L. Schor, R. J. Witt and R. D. Wittmeier.""February, 1986."Includes bibliographical references (leaf 44)Final project reportSupported by U.S. Dept. of Energy, Breeder Technology Program, Division of Educational Programs, Argonne National Laborator

Exploring Alumni Stories Through Qualitative Research

This presentation describes a project designed to connect current psychology undergraduates with alumni from the same program. Purposive sampling was used to recruit diverse alumni following different career paths (i.e., graduate school or straight to work), representing alumni who identified as first generation, nontraditional, Latina/Latino or as a student of color. Semi-structured interviews were conducted to understand alumni career paths and gather information about decision-making, barriers, supports, and advice for current psychology majors. Interviews were audio-taped and are currently being transcribed. Some alumni agreed to participate in an “Alumni Profile,” which highlighted specific alumni by name, shared details of individual’s specific story, and were made publicly available. The current presentation will share the experiences of the undergraduate researchers exploring qualitative research, learning about career options available after graduation, and benefits for current students

Two-Way Quantum Time Transfer: A Method for Daytime Space-Earth Links

Remote clock synchronization is crucial for many classical and quantum network applications. Current state-of-the-art remote clock synchronization techniques achieve femtosecond-scale clock stability utilizing frequency combs, which are supplementary to quantum-networking hardware. Demonstrating an alternative, we synchronize two remote clocks across our freespace testbed using a method called two-way quantum time transfer (QTT). In one second we reach picosecond-scale timing precision under very lossy and noisy channel conditions representative of daytime space-Earth links with commercial off-the-shelf quantum-photon sources and detection equipment. This work demonstrates how QTT is potentially relevant for daytime space-Earth quantum networking and/or providing high-precision secure timing in GPS-denied environments.Comment: arXiv admin note: text overlap with arXiv:2211.0073

The electric double layer has a life of its own

Using molecular dynamics simulations with recently developed importance sampling methods, we show that the differential capacitance of a model ionic liquid based double-layer capacitor exhibits an anomalous dependence on the applied electrical potential. Such behavior is qualitatively incompatible with standard mean-field theories of the electrical double layer, but is consistent with observations made in experiment. The anomalous response results from structural changes induced in the interfacial region of the ionic liquid as it develops a charge density to screen the charge induced on the electrode surface. These structural changes are strongly influenced by the out-of-plane layering of the electrolyte and are multifaceted, including an abrupt local ordering of the ions adsorbed in the plane of the electrode surface, reorientation of molecular ions, and the spontaneous exchange of ions between different layers of the electrolyte close to the electrode surface. The local ordering exhibits signatures of a first-order phase transition, which would indicate a singular charge-density transition in a macroscopic limit

The masses of the cataclysmic variables AC Cancri and V363 Aurigae

We present time-resolved spectroscopy and photometry of the double-lined eclipsing cataclysmic variables AC Cnc and V363 Aur (= Lanning 10). There is evidence of irradiation on the inner hemisphere of the secondary star in both systems, which we correct for using a model that reproduces the observations remarkably well. We find the radial velocity of the secondary star in AC Cnc to be KR= 176 ± 3 km s−1 and its rotational velocity to be v sin i= 135 ± 3 km s−1. From these parameters we obtain masses of M1= 0.76 ± 0.03 M⊙ for the white-dwarf primary and M2= 0.77 ± 0.05 M⊙ for the K2 ± 1V secondary star, giving a mass ratio of q= 1.02 ± 0.04. We measure the radial and rotational velocities of the G7 ± 2V secondary star in V363 Aur to be KR= 168 ± 5 km s−1 and v sin i= 143 ± 5 km s−1, respectively. The component masses of V363 Aur are M1= 0.90 ± 0.06 M⊙ and M2= 1.06 ± 0.11 M⊙, giving a mass ratio of q= 1.17 ± 0.07. The mass ratios for AC Cnc and V363 Aur fall within the theoretical limits for dynamically and thermally stable mass transfer. Both systems are similar to the SW Sex stars, exhibiting single-peaked emission lines with transient absorption features, high-velocity S-wave components and phase-offsets in their radial-velocity curves. The Balmer lines in V363 Aur show a rapid increase in flux around phase 0 followed by a rapid decrease, which we attribute to the eclipse of an optically thick region at the centre of the disc. This model could also account for the behaviour of other SW Sex stars where the Balmer lines show only a shallow eclipse compared to the continuum