1,782 research outputs found
Modelling groundwater/surface-water interaction in a managed riparian chalk valley wetland
Understanding hydrological processes in wetlands may be complicated by management practices and complex groundwater/surface water interactions. This is especially true for wetlands underlain by permeable geology, such as chalk. In this study, the physically based, distributed model MIKE SHE is used to simulate hydrological processes at the Centre for Ecology and Hydrology River Lambourn Observatory, Boxford, Berkshire, UK. This comprises a 10-ha lowland, chalk valley bottom, riparian wetland designated for its conservation value and scientific interest. Channel management and a compound geology exert important, but to date not completely understood, influences upon hydrological conditions. Model calibration and validation were based upon comparisons of observed and simulated groundwater heads and channel stages over an equally split 20-month period. Model results are generally consistent with field observations and include short-term responses to events as well as longer-term seasonal trends. An intrinsic difficulty in representing compressible, anisotropic soils limited otherwise excellent performance in some areas. Hydrological processes in the wetland are dominated by the interaction between groundwater and surface water. Channel stage provides head boundaries for broad water levels across the wetland, whilst areas of groundwater upwelling control discrete head elevations. A relic surface drainage network confines flooding extents and routes seepage to the main channels. In-channel macrophyte growth and its management have an acute effect on water levels and the proportional contribution of groundwater and surface water. The implications of model results for management of conservation species and their associated habitats are discusse
Building Capacity for Implementation Science in Precision Health and Society: Development of a Course for Professional and Graduate Students in Pharmacy
Training in the field of implementation science is critical for future pharmacists and pharmaceutical scientists to successfully implement precision health interventions in pharmacy practice. We developed an elective course for second- and third-year students at the UNC Eshelman School of Pharmacy to develop foundational knowledge in implementation science with a focus on precision health implementation. The eight-week course used a flipped classroom format featuring lecture videos, suggested readings, quizzes, guest lectures from experts, case studies, and a group project. We evaluated course quality through class participation, a pre- and post-test on course content, and a mixed-methods survey completed by the students. Overall engagement in in the course was high and students demonstrated significant improvement in understanding of implementation science and precision health. Strengths of the course as identified by students were the use of expert guest speakers, pre-class lectures, and case study exercises, while the ordering of content and improved connection between content and guest lectures were identified as areas for improvement. In conclusion, the elective course was well-received and meets a critical need in the field of pharmacy to build implementation science capacity. Future work is needed to expand and refine education for the implementation of precision health for pharmacy professionals
Projecting impacts of climate change on habitat availability in a macrophyte dominated chalk river
Climate change will impact fluvial ecosystems through changes in the flow regime. Physical habitat is an established measure of a river's ecological status when assessing changes to flow. Yet, it requires extensive datasets, is site specific, and does not account for dynamic processes; shortcomings that the use of hydrological and hydraulic models may alleviate. Here, simulated flows along a 600 m reach of the River Lambourn, Boxford, UK, were extracted from the 1D MIKE 11 hydraulic component of an integrated MIKE SHE model of the Centre for Ecology & Hydrology River Lambourn Observatory. In-channel seasonal macrophyte growth and management through cutting alter water levels, represented in the hydraulic model by manipulating channel bed roughness (Manning's n). Assessment of climate change used outputs from the UK Climate Projections 2009 ensemble of global climate models for the 2080s. River discharge outputs were disaggregated to provide velocity and depth profiles across 41 cross sections along the reach. These were integrated with habitat suitability criteria for brown trout (Salmo trutta) to generate a measure of available physical habitat. The influence of macrophyte growth caused the habitat-discharge relationship to be unusable in evaluating the sensitivity of brown trout to flow changes. Instead, projected time series were used to show an overall reduction in habitat availability, more for adult than juvenile trout. Results highlighted the impact of weed cutting, and its potential role in mitigating both flood risk and the ecological impacts of climate change. The use of a hydraulic model to assess physical habitat availability has worldwide applicability
Anomalous decay of pion and eta at finite density
We study the anomalous decays in the framework
of the three--flavor Nambu--Jona-Lasinio [NJL] model, in the vacuum and in
quark matter in --equilibrium. It is found that the behavior of the
relevant observables essentially reflects a manifestation of the partial
restoration of chiral symmetry, in non strange and strange sectors. The
probability of such decays decreases with density, showing that anomalous
mesonic interactions are significantly affected by the medium.Comment: 12 pages, 4 figures included; revised version, to be published in
Phys. Lett.
A model for interacting instabilities and texture dynamics of patterns
A simple model to study interacting instabilities and textures of resulting
patterns for thermal convection is presented. The model consisting of
twelve-mode dynamical system derived for periodic square lattice describes
convective patterns in the form of stripes and patchwork quilt. The interaction
between stationary zig-zag stripes and standing patchwork quilt pattern leads
to spatiotemporal patterns of twisted patchwork quilt. Textures of these
patterns, which depend strongly on Prandtl number, are investigated numerically
using the model. The model also shows an interesting possibility of a
multicritical point, where stability boundaries of four different structures
meet.Comment: 4 pages including 4 figures, page width revise
On the morphology of ammonium nitrate (III): theory and observation
The aim of this paper is to derive on a theoretical basis the morphology of crystals of ammonium nitrate, phase III, and to compare the results with experimental growth forms. The theory used is based on the concepts of periodic bond chain (PBC), F face and connected net, developed by Hartman and Perdok. Further an Ising model is used to determine roughening temperatures. Based on different criteria theoretical growth forms are predicted and compared with experiments
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Separation of fischer-Tropsch Wax from Catalyst by Supercritical Extraction.
Although alkanes are the major constituent of a Fischer-Tropsch wax, significant quantities (e.g., up to 30 wt %) of long-chain alcohol and alkene compounds can also be found in a F-T wax. With the lack of experimental data, the effect that the hydroxy and double-bond functional groups have on the phase behavior of systems containing long- chain hydrocarbons is unknown. Therefore, the phase behavior of the system n-hexane/1-hexadecanol was measured for comparison with the previously measured system n-hexane/hexadecane. Vapor and liquid equilibrium compositions and mixture critical points were measured at 198.9, 251.3, 299.2, and 349.9 {degrees}C at pressures ranging from 6.2 to 46.4 bar. Temperature and pressure measurements for all isotherms are believed to be accurate to better than plus or minus 3 and 4 percent, respectively. Results indicate that the addition of the alcohol group to a C 16 hydrocarbon chain significantly affects the phase behavior with hexane, with the two-phase region extending to significantly higher (i.e., up to about 10 bar higher) pressures. The presence of an alcohol group was also found to be an impediment to obtaining a good fit of the experimental data with the Peng-Robinson equation
Intra-molecular coupling as a mechanism for a liquid-liquid phase transition
We study a model for water with a tunable intra-molecular interaction
, using mean field theory and off-lattice Monte Carlo simulations.
For all , the model displays a temperature of maximum
density.For a finite intra-molecular interaction ,our
calculations support the presence of a liquid-liquid phase transition with a
possible liquid-liquid critical point for water, likely pre-empted by
inevitable freezing. For J=0 the liquid-liquid critical point disappears at
T=0.Comment: 8 pages, 4 figure
SO(10) unified models and soft leptogenesis
Motivated by the fact that, in some realistic models combining SO(10) GUTs
and flavour symmetries, it is not possible to achieve the required baryon
asymmetry through the CP asymmetry generated in the decay of right-handed
neutrinos, we take a fresh look on how deep this connection is in SO(10). The
common characteristics of these models are that they use the see-saw with
right-handed neutrinos, predict a normal hierarchy of masses for the neutrinos
observed in oscillating experiments and in the basis where the right-handed
Majorana mass is diagonal, the charged lepton mixings are tiny.
In addition these models link the up-quark Yukawa matrix to the neutrino
Yukawa matrix Y^\nu with the special feature of Y^\nu_{11}-> 0 Using this
condition, we find that the required baryon asymmetry of the Universe can be
explained by the soft leptogenesis using the soft B parameter of the second
lightest right-handed neutrino whose mass turns out to be around 10^8 GeV. It
is pointed out that a natural way to do so is to use no-scale supergravity
where the value of B ~1 GeV is set through gauge-loop corrections.Comment: 26 pages, 2 figures. Added references, new appendix of a relevant fit
and improved comment
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