277 research outputs found

    Utilizing Satellite Based Observations and Physical Hydrological Modeling for Freshwater Ecosystem Health in the Lower Mekong River Basin

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    Freshwater availability is necessary to promote economic growth through agriculture, fisheries, transport, environmental health, and social equity.The National Aeronautics and Space Administration (NASA) and the Conservation International (CI) are partnering to use remote sensing Earth observations to improve regional efforts that assess natural resources for conservation and sustainable management. (Vollmer et al.,2018) have presented the social-ecological framework named the Freshwater Health Index (FHI), which takes account of the interplay between governance, stakeholders, freshwater ecosystems and the ecosystem services they provide.In this work, we develop decision support and making tools for natural resources conservation in the Lower Mekong by leveraging the FHI framework, multiple data products, and hydrological modeling capabilities (Mohammed et al., 2018). Modeling capabilities enable the integration of satellite-based daily gridded precipitation, air temperature, digital elevation model, soil characteristics, and land cover and land use information to simulate water flux framework

    Classical Many-particle Clusters in Two Dimensions

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    We report on a study of a classical, finite system of confined particles in two dimensions with a two-body repulsive interaction. We first develop a simple analytical method to obtain equilibrium configurations and energies for few particles. When the confinement is harmonic, we prove that the first transition from a single shell occurs when the number of particles changes from five to six. The shell structure in the case of an arbitrary number of particles is shown to be independent of the strength of the interaction but dependent only on its functional form. It is also independent of the magnetic field strength when included. We further study the effect of the functional form of the confinement potential on the shell structure. Finally we report some interesting results when a three-body interaction is included, albeit in a particular model.Comment: Minor corrections, a few references added. To appear in J. Phys: Condensed Matte

    Novel classical ground state of a many body system in arbitrary dimensions

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    The classical ground state of a D- dimensional many body system with two and three body interactions is studied as a function of the strength of the three body interaction. We prove exactly that beyond a critical strength of the three body interaction, the classical ground state of the system is one in which all the particles are on a line. The positions of the particles in this string configuration are uniquely determined by the zeros of the Hermite polynomials.Comment: 4 pages, RevTeX, no figure; version to appear in Physical Review Letter

    Effect of planned place of birth on obstetric interventions and maternal outcomes among low-risk women : a cohort study in the Netherlands

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    Background: The use of interventions in childbirth has increased the past decades. There is concern that some women might receive more interventions than they really need. For low-risk women, midwife-led birth settings may be of importance as a counterbalance towards the increasing rate of interventions. The effect of planned place of birth on interventions in the Netherlands is not yet clear. This study aims to give insight into differences in obstetric interventions and maternal outcomes for planned home versus planned hospital birth among women in midwife-led care. Methods: Women from twenty practices across the Netherlands were included in 2009 and 2010. Of these, 3495 were low-risk and in midwife-led care at the onset of labour. Information about planned place of birth and outcomes, including instrumental birth (caesarean section, vacuum or forceps birth), labour augmentation, episiotomy, oxytocin in third stage, postpartum haemorrhage >1000 ml and perineal damage, came from the national midwife-led care perinatal database, and a postpartum questionnaire. Results: Women who planned home birth more often had spontaneous birth (nulliparous women aOR 1.38, 95 % CI 1.08-1.76, parous women aOR 2.29, 95 % CI 1.21-4.36) and less often episiotomy (nulliparous women aOR 0.73, 0.58-0.91, parous women aOR 0.47, 0.33-0.68) and use of oxytocin in the third stage (nulliparous women aOR 0.58, 0.42-0.80, parous women aOR 0.47, 0.37-0.60) compared to women who planned hospital birth. Nulliparous women more often had anal sphincter damage (aOR 1.75, 1.01-3.03), but the difference was not statistically significant if women who had caesarean sections were excluded. Parous women less often had labour augmentation (aOR 0.55, 0.36-0.82) and more often an intact perineum (aOR 1.65, 1.34-2.03). There were no differences in rates of vacuum/forceps birth, unplanned caesarean section and postpartum haemorrhage >1000 ml. Conclusions: Women who planned home birth were more likely to give birth spontaneously and had fewer medical interventions. Β© 2016 The Author(s)

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    We demonstrate the suitability of microcavities based on circular grating resonators (CGRs) as fast switches. This type of optical resonator is characterized by a high quality factor and very small mode volume. The waveguide-coupled CGRs are fabricated with silicon-on-insulator technology compatible with standard complementary metal-oxide semiconductor (CMOS) processing. The linear optical properties of the CGRs are investigated by transmission spectroscopy. From 3D finite-difference time-domain simulations of isolated CGRs, we identify the measured resonances. We probe the spatial distribution and the parasitic losses of a resonant optical mode with scanning near-field optical microscopy. We observe fast all-optical switching within a few picoseconds by optically generating free charge carriers within the cavity. (C) 2009 Optical Society of Americ

    Earth Observations and Integrative Models in Support of Food and Water Security

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    Global food production depends upon many factors that Earth observing satellites routinely measure about water, energy, weather, and ecosystems. Increasingly sophisticated, publicly-available satellite data products can improve efficiencies in resource management and provide earlier indication of environmental disruption. Satellite remote sensing provides a consistent, long-term record that can be used effectively to detect large-scale features over time, such as a developing drought. Accuracy and capabilities have increased along with the range of Earth observations and derived products that can support food security decisions with actionable information. This paper highlights major capabilities facilitated by satellite observations and physical models that have been developed and validated using remotely-sensed observations. Although we primarily focus on variables relevant to agriculture, we also include a brief description of the growing use of Earth observations in support of aquaculture and fisheries

    JUICE - Juelich Initiative Cell Cluster Report 2007

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    Modeling of dielectric hysteresis loops in ferroelectric semiconductors with charged defects

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    We have proposed the phenomenological description of dielectric hysteresis loops in ferroelectric semiconductors with charged defects and prevailing extrinsic conductivity. Exactly we have modified Landau-Ginsburg approach and shown that the macroscopic state of the aforementioned inhomogeneous system can be described by three coupled equations for three order parameters. Both the experimentally observed coercive field values well below the thermodynamic one and the various hysteresis loop deformations (constricted and double loops) have been obtained in the framework of our model. The obtained results quantitatively explain the ferroelectric switching in such ferroelectric materials as thick PZT films.Comment: 21 pages, 10 figures, sent to Journal of Physics: Condensed Matte
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