23,946 research outputs found

    Helping Kindergarteners Make Sense of Numbers to 100

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    The authors share what was learned about kindergarteners\u27 abilities to make sense of numbers to 100 when one of the authors, Linda Jaslow, took over a kindergarten class from February through the end of the school year. Through examples of how she engaged her students in nine weeks of problem solving and discussions focused on making sense of the number system, we provide evidence that the children grew substantially in their ability to count and show understanding when counting by 10\u27s and using 10\u27s during problem solving. Suggestions for tasks to promote continued growth are also provided. Throughout this teaching experience, Mrs. Jaslow was reminded of the complexity of making sense of our number system, and this article showcases her instructional decision making that was based on inquiry into children\u27s thinking. By valuing children\u27s existing ideas, Mrs. Jaslow could use that thinking to help guide her instruction

    Coarsening Dynamics of Granular Heaplets in Tapped Granular Layers

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    A semi-continuum model is introduced to study the dynamics of the formation of granular heaplets in tapped granular layers. By taking into account the energy dissipation of collisions and screening effects due to avalanches, this model is able to reproduce qualitatively the pattern of these heaplets. Our simulations show that the granular heaplets are characterised by an effective surface tension which depends on the magnitude of the tapping intensity. Also, we observe that there is a coarsening effect in that the average size of the heaplets, V grows as the number of taps k increases. The growth law at intermediate times can be fitted by a scaling function V ~ k^z but the range of validity of the power law is limited by size effects. The growth exponent z appears to diverge as the tapping intensity is increased.Comment: 4 pages, 4 figure

    Alternating magnetic anisotropy of Li2_2(Li1xTx_{1-x}T_x)N with TT = Mn, Fe, Co, and Ni

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    Substantial amounts of the transition metals Mn, Fe, Co, and Ni can be substituted for Li in single crystalline Li2_2(Li1xTx_{1-x}T_x)N. Isothermal and temperature-dependent magnetization measurements reveal local magnetic moments with magnitudes significantly exceeding the spin-only value. The additional contributions stem from unquenched orbital moments that lead to rare-earth-like behavior of the magnetic properties. Accordingly, extremely large magnetic anisotropies have been found. Most notably, the magnetic anisotropy alternates as easy-plane \rightarrow easy-axis \rightarrow easy-plane \rightarrow easy-axis when progressing from TT = Mn \rightarrow Fe \rightarrow Co \rightarrow Ni. This behavior can be understood based on a perturbation approach in an analytical, single-ion model. The calculated magnetic anisotropies show a surprisingly good agreement with the experiment and capture the basic features observed for the different transition metals.Comment: 5 pages, 3 figures, published as PRB Rapid Communication, Fig. 3 update

    Application of risk-based, adaptive pathways to climate adaptation planning for public conservation areas in NSW, Australia

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    © 2019 by the authors. Globally, areas of high-quality wildlife habitat of significant environmental value are at risk of permanent damage from climate change. These areas represent social-ecological systems that will require increasing management intervention to maintain their biological and socio-cultural values. Managers of protected areas have begun to recognize the inevitability of ecosystem change and the need to embrace dynamic approaches to intervention. However, significant uncertainty remains about the onset and severity of some impacts, which makes planning difficult. For Indigenous communities, there are intrinsic links between cultural heritage and the conservation of place and biodiversity that need to be better integrated in protected area planning and management. In New SouthWales, Australia, management of public conservation reserves and national parks is the responsibility of a State government agency, the National Parks andWildlife Service (NPWS). This paper describes the outcomes of a participatory planning process with NPWS staff to, firstly, identify the options available, the available 'tool kit', to manage biodiversity and cultural heritage in protected areas; secondly, explore how the selection of management actions from the 'tool kit' is associated with the level of climate risk to biodiversity or cultural heritage assets; and thirdly, to understand how the form of individual management actions might adapt to changes in climate risk. Combining these three elements into a series of risk-based, adaptive pathways for conservation of biodiversity and cultural heritage is a novel approach that is currently supporting place-based planning for public conservation areas. Incorporation of the trade-offs and synergies in seeking to effectively manage these discrete but related types of values and the implications for conservation practice are discussed

    Gravitational Waves in Bianchi Type-I Universes I: The Classical Theory

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    The propagation of classical gravitational waves in Bianchi Type-I universes is studied. We find that gravitational waves in Bianchi Type-I universes are not equivalent to two minimally coupled massless scalar fields as it is for the Robertson-Walker universe. Due to its tensorial nature, the gravitational wave is much more sensitive to the anisotropy of the spacetime than the scalar field is and it gains an effective mass term. Moreover, we find a coupling between the two polarization states of the gravitational wave which is also not present in the Robertson-Walker universe.Comment: 34 papers, written in ReVTeX, submitted to Physical Review

    Direct association between rainfall and non-typhoidal <i>Salmonella</i> bloodstream infections in hospital-admitted children in the Democratic Republic of Congo

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    Abstract Non-typhoidal Salmonella (NTS) ranks first among causes of bloodstream infection in children under five years old in the Democratic Republic of Congo and has a case fatality rate of 15%. Main host-associated risk factors are Plasmodium falciparum malaria, anemia and malnutrition. NTS transmission in sub-Saharan Africa is poorly understood. NTS bloodstream infections mostly occur during the rainy season, which may reflect seasonal variation in either environmental transmission or host susceptibility. We hypothesized that environment- and host-associated factors contribute independently to the seasonal variation in NTS bloodstream infections in children under five years old admitted to Kisantu referral hospital in 2013–2019. We used remotely sensed rainfall and temperature data as proxies for environmental factors and hospital data for host-associated factors. We used principal component analysis to disentangle the interrelated environment- and host-associated factors. With timeseries regression, we demonstrated a direct association between rainfall and NTS variation, independent of host-associated factors. While the latter explained 17.5% of NTS variation, rainfall explained an additional 9%. The direct association with rainfall points to environmental NTS transmission, which should be explored by environmental sampling studies. Environmental and climate change may increase NTS transmission directly or via host susceptibility, which highlights the importance of preventive public health interventions

    Bogomol'nyi Limit For Magnetic Vortices In Rotating Superconductor

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    This work is the sequel of a previous investigation of stationary and cylindrically symmetric vortex configurations for simple models representing an incompressible non-relativistic superconductor in a rigidly rotating background. In the present paper, we carry out our analysis with a generalized Ginzburg-Landau description of the superconductor, which provides a prescription for the radial profile of the normal density within the vortex. Within this framework, it is shown that the Bogomol'nyi limit condition marking the boundary between type I and type II behavior is unaffected by the rotation of the background.Comment: 7 pages, uses RevTeX, submitted to Phys.Rev.

    Towards a climate change adaptation strategy for national parks: Adaptive management pathways under dynamic risk

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    © 2018 Elsevier Ltd Government seeks to manage public protected areas, such as national parks, to conserve high-quality wildlife habitats and provide essential ecosystems services at risk of permanent damage or extinction from climate change. The complexity of the organizational structure required to deliver this breadth of functions, coupled to uncertainty surrounding the onset and severity of climate impacts at local scale, impedes planning for climate change. This paper describes the development of an adaptation planning tool and its application in a pilot planning process for the National Parks and Wildlife Service, the agency of the New South Wales (NSW) Government (Australia) responsible for management of national parks and public conservation reserves. The process involved close engagement in knowledge co-production in participatory workshops, and employed two complementary techniques, adaptive pathways and risk assessment. It successfully elicited tacit knowledge of agency staff about the range of interventions available, the need for management practices to evolve, and of discontinuities in management pathways in a dynamic risk environment. Findings suggest that management effort across the NSW reserve system will increase as climate risk rises. Consequently, government will need to respond to increased demand for resources, for better targeting of those resources, and for management innovation in how resources are deployed to support adaptation that is both anticipatory and transformative

    Preferential Binding Effects On Protein Structure and Dynamics Revealed by Coarse-Grained Monte Carlo Simulation

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    The effect of preferential binding of solute molecules within an aqueous solution on the structure and dynamics of the histone H3.1 protein is examined by a coarse-grained Monte Carlo simulation. The knowledge-based residue-residue and hydropathy-index-based residue-solvent interactions are used as input to analyze a number of local and global physical quantities as a function of the residue-solvent interaction strength (f). Results from simulations that treat the aqueous solution as a homogeneous effective solvent medium are compared to when positional fluctuations of the solute molecules are explicitly considered. While the radius of gyration (Rg) of the protein exhibits a non-monotonic dependence on solvent interaction over a wide range of f within an effective medium, an abrupt collapse in Rg occurs in a narrow range of f when solute molecules rapidly bind to a preferential set of sites on the protein. The structure factor S(q) of the protein with wave vector (q) becomes oscillatory in the collapsed state, which reflects segmental correlations caused by spatial fluctuations in solute-protein binding. Spatial fluctuations in solute binding also modify the effective dimension (D) of the protein in fibrous (D ∼ 1.3), random-coil (D ∼ 1.75), and globular (D ∼ 3) conformational ensembles as the interaction strength increases, which differ from an effective medium with respect to the magnitude of D and the length scale
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