581 research outputs found

    Crafting Relevant Community Partnerships Using Archives

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    Historically, archives have told the stories of the dominant society. Increasingly, archives are exploring and filling some of the silences left by the exclusion of many voices. Oral history is a way of actively collecting stories which may not exist in written form. Both the University of Nebraska at Omaha’s LGBTQ+ Voices: The Queer Omaha Archives Oral History Project and the University of Nebraska at Kearney Archives and Special Collections’ Coming to the Plains: Latin@ Stories in Central Nebraska project engage members of diverse communities in telling their own stories. This session will talk about the origins of each project, the challenges faced, the evolution of the projects, and future pathways. Specific issues discussed will include planning oral history projects, collaborating with communities, faculty, and students on all stages of an oral history project, gaining grant funding to scale up projects, and publicizing and sharing the products of oral histories

    Assimilation de données d'humidité des sols pour la prévision de crues : comparaison d'un modÚle pluie-débit conceptuel et d'un modÚle intégrant une interface sol-végétation-atmosphÚre

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    Le but de cet article est de prĂ©senter une mĂ©thodologie de mise Ă  jour des paramĂštres de modĂšles pluie-dĂ©bit en pĂ©riode de crue. Elle a Ă©tĂ© mise au point afin d'amĂ©liorer un des aspects de la gestion des rĂ©servoirs dans un contexte opĂ©rationnel de protection contre les crues: la rĂ©duction des incertitudes sur la prĂ©vision des dĂ©bits. L'originalitĂ© de la mĂ©thode proposĂ©e rĂ©side dans le fait que l'on utilise non seulement une information sur les dĂ©bits mais aussi une information sur l'humiditĂ© du sol. L'objectif de l'Ă©tude est d'Ă©valuer l'intĂ©rĂȘt de l'introduction de cette information supplĂ©mentaire. Pour cela, les donnĂ©es d'humiditĂ© du sol sont introduites au sein du modĂšle par l'intermĂ©diaire d'une relation de passage Ă©tablie entre l'humiditĂ© mesurĂ©e in situ et l'humiditĂ© calculĂ©e implicitement ou explicitement par les modĂšles. Cette mĂ©thodologie a Ă©tĂ© testĂ©e dans le cadre du projet europĂ©en AIMWATER sur quatre sous-bassins de la Seine en amont de Paris (France). Deux modĂšles pluie-dĂ©bit sont utilisĂ©s dans cette Ă©tude, un modĂšle conceptuel semi-emprique et un modĂšle conceptuel couplĂ© Ă  un schĂ©ma de surface simulant une interface sol-vĂ©gĂ©tation-atmosphĂšre et permettant de calculer l'Ă©volution de l'humiditĂ© du sol Ă  diffĂ©rentes profondeurs. Cette approche comparative Ă©tudie l'intĂ©rĂȘt d'un tel modĂšle couplĂ© par rapport au modĂšle conceptuel semi-empirique sans reprĂ©sentation explicite des phĂ©nomĂšnes se produisant Ă  l'interface sol-vĂ©gĂ©tation-atmosphĂšre.Improving the accuracy of rainfall-runoff models and in particular their performances in flood prediction is a key point of continental hydrology. Methods have been developed to improve flood prediction in hydrology based on a better compliance of the model with current observations prior to its use in forecasting mode. This operation has been termed updating in hydrology and assimilation in meteorology. The fundamental idea is that if model predictions diverge from observations at a given time, there is little chance that future estimations will approach correct values. The improvement then comes from a correction of the trajectory of the model based on observations during the period preceding the day when a prediction into the immediate or long-term future is desired. This can be dealt with by a correction of model parameters, which is usually called "parameter updating".The inability of rainfall-runoff models to produce correct streamflow values generally translates into parameter uncertainty. Parameter calibration is the means used by a model structure to adjust to a given set of data. Therefore, a parameter updating methodology seems to be a natural way to amend errors in streamflow values. In this paper, a specific methodology of parameter updating is presented. The main feature of this method is that it does not carry out updating by reference only to recent streamflow observations, as classic procedures do, but also to soil moisture measurements, which can be retrieved daily from TDR probes. Indeed, it appears that the integration of soil moisture data allows better control of the evolution of the model and improves its performances, in particular in terms of forecasting.The aim of the research was to assess the usefulness of this additional soil moisture information. To this end, an approach has been suggested that gradually introduces additional information thanks to a constraint relationship between observed and modelled soil moisture. In fact, soil moisture can be calculated implicitly or explicitly by the model when extracting step-by-step the values of the model's store contents. This methodology was put forward for use in the European AIMWATER project on four catchments within the Seine River basin upstream of Paris (France). The other issue addressed in this paper was whether or not it is necessary to use a model that simulates explicitly the evolution of soil moisture at different depths. One can argue that if the model employed does not feature a store that can be identified closely to the observed soil moisture, there would be no possibility of benefiting from such measurements. On the other hand, it can be argued that if soil moisture is a model output, all the information drawn from soil moisture observations will be directed at improving this specific output at the expense of improving streamflow values. To answer this issue, two models were tested. The first model, GR4j, has no explicit counterpart for soil moisture measurements. The second one, GRHum, has been especially developed to introduce a two-layer soil reservoir that simulates the surface and sub-surface soil moisture.Since the aim of the present research was to analyse different ways of accounting for soil moisture, and to identify the one that offers the best prospects, several tests were carried out, using different relationships between observed and modelled soil moisture. Indeed, TDR probes give point measurements of soil moisture at several depths and several store contents can be taken into account in a constraint relationship.First, for both GR4j and GRHum models, tests showed that performances for flood forecasting are significantly improved when assimilating in situ measurements of soil moisture at a daily time-step, especially for the basins where poor simulations are obtained. It is also noteworthy that performances are very dependent on the items taken into account in a constraint relationship.Secondly, the GRHum model did not appear to be more efficient than the GR4j model when assimilating both streamflow and soil moisture data. However, the GRHum model gave the best results when assimilating only streamflow data, and superficial soil moisture seemed to fit the GRHum better than the GR4j model.Finally, although the tests required perfect foreknowledge of rainfall, the results of the research are encouraging from an operational point of view. Another interesting perspective is provided by the Earth Observation data. Indeed, previous studies have shown that soil moisture can be derived from EO data using, for example, microwave spaceborne Synthetic Aperture Radar (SAR) images (QUESNEY et al., 2000). This type of catchment-scale data could be more relevant than a local measure given by TDR probes (PAUWELS et al., 2002)

    Drug-eluting Bead Chemoembolization for the Treatment of Nonresectable Hepatic Carcinoma in Dogs: A Prospective Clinical Trial

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    Abstract Background Effective treatment options for nonresectable hepatic carcinoma (HC) in dogs are limited. Hypothesis/Objective Objectives were to report outcomes, complications, and tumor responses via computed tomography (CT) assessment after drug‐eluting bead transarterial chemoembolization (DEB‐TACE) for nonresectable HC in dogs. The authors hypothesized that major complications would be uncommon and short‐term CT assessment would demonstrate stable disease or partial response. Animals Client‐owned dogs (n = 16) with nonresectable HC. Methods Prospective, single‐arm clinical trial. Drug‐eluting bead transarterial chemoembolization was performed to varying levels of blood flow stasis. Computed tomography imaging was compared before and approximately 12 weeks after initial treatment. Results Drug‐eluting bead transarterial chemoembolization was successfully administered in all attempts. Based on percent change in elliptical tumor volume response (mL), stable disease (8/13; 62%) was the most common outcome followed by partial response (3/13; 23%) and progressive disease (2/13; 15%) with a median of 74 days (range, 39‐125) after initial treatment. Median tumor volume (mL) after DEB‐TACE decreased in volume by 13% (range, 56% decrease to 77% increase). Mild complications consistent with postembolization syndrome occurred after 7/27 (26%) treatments. Major complications occurred after 3/27 (11%) treatments: hepatic abscess/septicemia (2) and cholecystitis/death (1), resulting in treatment‐induced death after 2/27 (7%) treatments. Median survival time after treatment was 337 days (range, 22‐1061). Dogs with a presenting complaint of weight loss (P = .02) had a significantly shorter median survival time (126 days; range, 46‐337) than those dogs without prior history of weight loss (582 days; range, 22‐1061). Conclusions Drug‐eluting bead transarterial chemoembolization for nonresectable HC is a feasible procedure, which promoted stable disease or partial response in 85% of dogs in this study sample

    Photosynthetic and growth response of freshwater picocyanobacteria are strain-specific and sensitive to photoacclimation

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    We investigated the effect of different light conditions on primary production and growth rates of three closely related freshwater picocyanobacterial strains from three different ribotypes in laboratory cultures. The primary goal was to test whether not only different pigment types (PC-rich versus PE-rich) but also other physiological characteristics suggested by different phylogenetic positions could affect growth and photosynthetic rates of picocyanobacteria. Secondly, we tested whether photacclimation is strain specific. Experiments were conducted over light intensities ranging from 6 to 1500 ÎŒmol photons m−2 s−1 with cultures that were acclimated to low (10 ÎŒmol photons m−2 s−1) and moderate (100 ÎŒmol photons m−2 s−1) irradiance. The PE-rich strain was sensitive to high light conditions and reached highest photosynthesis and growth rates at low light intensities. The relative effect of photoacclimation was different between the two PC-rich strains, with one strain showing only moderate changes in growth rates in response to the light level used during the acclimation period. Overall, growth rates differed widely in response to light intensity and photoacclimation. Photoacclimation significantly affected both primary production and growth rates of all three strains investigated. We conclude that strain-specific photoacclimation adds to the niche partitioning among closely related freshwater picocyanobacteria

    Uncovering selective excitations using the resonant profile of indirect inelastic x-ray scattering in correlated materials: Observing two-magnon scattering and relation to the dynamical structure factor

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    Resonant inelastic x-ray scattering (RIXS) is a spectroscopic technique which has been widely used to study various elementary excitations in correlated and other condensed matter systems. For strongly correlated materials, besides boosting the overall signal the dependence of the resonant profile on incident photon energy is still not fully understood. Previous endeavors in connecting indirect RIXS, such as Cu K-edge for example where scattering takes place only via the core-hole created as an intermediate state, with the charge dynamical structure factor S(q,\omega) neglected complicated dependence on the intermediate state configuration. To resolve this issue, we performed an exact diagonalization study of the RIXS cross-section using the single-band Hubbard model by fully addressing the intermediate state contribution. Our results are relevant to indirect RIXS in correlated materials, such as high Tc cuprates. We demonstrate that RIXS spectra can be reduced to S(q,\omega) when there is no screening channel for the core-hole potential in the intermediate state. We also show that two-magnon excitations are highlighted at the resonant photon energy when the core-hole potential in the corresponding intermediate state is poorly screened. Our results demonstrate that different elementary excitations can be emphasized at different intermediate states, such that selecting the exact incident energy is critical when trying to capture a particular elementary excitation.Comment: 11 pages, 3 figure

    Phase diagram and optical conductivity of the one-dimensional spinless Holstein model

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    The effects of quantum lattice fluctuations on the Peierls transition and the optical conductivity in the one-dimensional Holstein model of spinless fermions have been studied by developing an analytical approach, based on the unitary transformation method. We show that when the electron-phonon coupling constant decreases to a finite critical value the Peierls dimerization is destroyed by the quantum lattice fluctuations. The dimerization gap is much more reduced by the quantum lattice fluctuations than the phonon order parameter. The calculated optical conductivity does not have the inverse-square-root singularity but have a peak above the gap edge and there exists a significant tail below the peak. The peak of optical-conductivity spectrum is not directly corresponding to the dimerized gap. Our results of the phase diagram and the spectral-weight function agree with those of the density matrix renormalization group and the exact diagonalization methods.Comment: 9 pages, 4 figures include

    Exploring high-end climate change scenarios for flood protection of the Netherlands

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    This international scientific assessment has been carried out at the request of the Dutch Delta Committee. The "Deltacommissie" requested that the assessment explore the high-end climate change scenarios for flood protection of the Netherlands. It is a state-of–the art scientific assessment of the upper bound values and longer term projections (for sea level rise up to 2200) of climate induced sea level rise, changing storm surge conditions and peak discharge of river Rhine. It comprises a review of recent studies, model projections and expert opinions of more than 20 leading climate scientists from different countries around the North Sea, Australia and the US
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