1,237 research outputs found

    Double ionization of a three-electron atom: Spin correlation effects

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    We study the effects of spin degrees of freedom and wave function symmetries on double ionization in three-electron systems. Each electron is assigned one spatial degree of freedom. The resulting three-dimensional Schr\"odinger equation is integrated numerically using grid-based Fourier transforms. We reveal three-electron effects on the double ionization yield by comparing signals for different ionization channels. We explain our findings by the existence of fundamental differences between three-electronic and truly two-electronic spin-resolved ionization schemes. We find, for instance, that double ionization from a three-electron system is dominated by electrons that have the opposite spin

    Developing Multiplication Fact Fluency

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    Using specific components of three broad learning theories—cognitive, social-interactional, and behavioral—students in 3rd, 4th and 5th grade classrooms were given multiplication fact fluency instruction over a period of five weeks for 10-15 minutes each day. Two different approaches were utilized with two distinct groups of students for the purpose of comparing different approaches to fluency development. Results indicate that students using a strategy-based approach for fluency development by means of instructional tasks emphasizing social-interactional and cognitive theories (particularly Bruner’s theory of Modes of Representation) increased multiplication fact fluency, with a greater degree of consistency, than students using a drill-based approach emphasizing behavioristic techniques such as repetition and memorization

    Rethinking the economic costs of malaria at the household level: Evidence from applying a new analytical framework in rural Kenya

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    BACKGROUND: Malaria imposes significant costs on households and the poor are disproportionately affected. However, cost data are often from quantitative surveys with a fixed recall period. They do not capture costs that unfold slowly over time, or seasonal variations. Few studies investigate the different pathways through which malaria contributes towards poverty. In this paper, a framework indicating the complex links between malaria, poverty and vulnerability at the household level is developed and applied using data from rural Kenya. METHODS: Cross-sectional surveys in a wet and dry season provide data on treatment-seeking, cost-burdens and coping strategies (n = 294 and n = 285 households respectively). 15 case study households purposively selected from the survey and followed for one year provide in-depth qualitative information on the links between malaria, vulnerability and poverty. RESULTS: Mean direct cost burdens were 7.1% and 5.9% of total household expenditure in the wet and dry seasons respectively. Case study data revealed no clear relationship between cost burdens and vulnerability status at the end of the year. Most important was household vulnerability status at the outset. Households reporting major malaria episodes and other shocks prior to the study descended further into poverty over the year. Wealthier households were better able to cope. CONCLUSION: The impacts of malaria on household economic status unfold slowly over time. Coping strategies adopted can have negative implications, influencing household ability to withstand malaria and other contingencies in future. To protect the poor and vulnerable, malaria control policies need to be integrated into development and poverty reduction programmes

    Restricted space ab initio models for double ionization by strong laser pulses

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    Double electron ionisation process occurs when an intense laser pulse interacts with atoms or molecules. Exact {\it ab initio} numerical simulation of such a situation is extremely computer resources demanding, thus often one is forced to apply reduced dimensionality models to get insight into the physics of the process. The performance of several algorithms for simulating double electron ionization by strong femtosecond laser pulses are studied. The obtained ionization yields and the momentum distributions of the released electrons are compared, and the effects of the model dimensionality on the ionization dynamics discussed

    Fluvial Sediment Aggradation and Incision in NW Sub-Himalaya

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    Abstract HKT-ISTP 2013 A

    Elementary School Experience with Comprehension Testing May Influence Metacomprehension Accuracy Among Seventh and Eighth Graders

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    We explored whether exposure to different kinds of comprehension tests during elementary years influenced metacomprehension accuracy among 7th and 8th graders. This research was conducted in a kindergarten through eighth grade charter school with an expeditionary learning curriculum. In literacy instruction, teachers emphasize reading for meaning and inference building, and they regularly assess deep comprehension with summarization, discussion, dialogic reasoning and prediction activities throughout the elementary years. The school recently expanded, doubling enrollments in 7th and 8th grades. Thus, approximately half of the students had long-term exposure to the curriculum and the other half did not. In Study 1, metacomprehension accuracy using the standard relative accuracy paradigm was significantly better for long-time students than for newcomers. In Study 2, all students engaged in delayed-keyword generation before judging their comprehension of texts. Metacomprehension accuracy was again significantly better for long-time students than for newcomers. Further, the superior monitoring accuracy led to more effective regulation of study, as seen in better decisions about which texts to restudy, that led, in turn, better comprehension. The results suggest the importance of early exposure to comprehension tests for developing skills in comprehension monitoring and self-regulated learning

    Supramolecular Assembly of Pyrene-DNA Conjugates into Columnar Vesicles

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    This poster describes the supramolecular assembly of DNA conjugates functionalized with pyrene sticky-ends. After hybridization, the 3’-end modified DNA single strands self-assembled into vesicles with diameters of 50–200 nm. Columnar packed aggregated and multilamellar vesicles were observed by cryo-EM

    Anisotropic Electronic Structure of the Kondo Semiconductor CeFe2Al10 Studied by Optical Conductivity

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    We report temperature-dependent polarized optical conductivity [σ(ω)\sigma(\omega)] spectra of CeFe2_2Al10_{10}, which is a reference material for CeRu2_2Al10_{10} and CeOs2_2Al10_{10} with an anomalous magnetic transition at 28 K. The σ(ω)\sigma(\omega) spectrum along the b-axis differs greatly from that in the acac-plane, indicating that this material has an anisotropic electronic structure. At low temperatures, in all axes, a shoulder structure due to the optical transition across the hybridization gap between the conduction band and the localized 4f4f states, namely cc-ff hybridization, appears at 55 meV. However, the gap opening temperature and the temperature of appearance of the quasiparticle Drude weight are strongly anisotropic indicating the anisotropic Kondo temperature. The strong anisotropic nature in both electronic structure and Kondo temperature is considered to be relevant the anomalous magnetic phase transition in CeRu2_2Al10_{10} and CeOs2_2Al10_{10}.Comment: 5 pages, 4 figure

    Technical Performance and Energy Intensity of the Electrode-Separator Composite Manufacturing Process

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    AbstractEnergy storage is one of the key technological factors that determine the success of a sustainable future. Especially green mobility concepts for electric or hybrid electric vehicles highly depend upon storage technologies with high energy density and light-weight materials. At the same time, innovative production processes should be conceived that ensure energy and resource efficient manufacturing of these energy storage devices. This paper focuses on the technical as well as dynamic energetic performance analysis and evaluation of an innovative electrode-separator composite manufacturing process of lithium-ion batteries for automotive applications. The technical performance indicators such as battery capacity and the energy intensity of the manufacturing process are highly dependent upon process parameters, machine and product design. Hence, in-depth process knowledge must be acquired to understand interdependencies between all system components. Thus, the manufacturing process is analysed in terms of its dynamics, and correlations between process parameters, process energy demand and final product properties are assessed. The resulting knowledge is important for the subsequent design of large-scale products and processes involved design, as well as for characterisation of the manufacturing process for life cycle inventory databases or life cycle costing calculations
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