3,165 research outputs found
The Impact of Recent Extradition Cases Involving Canada and the United States: A Canadian Perspective
extradition in Canada and the United State
Coupled quintessence and vacuum decay
We discuss observational consequences of a class of cosmological models
characterized by the dilution of pressureless matter attenuated with respect to
the usual scaling due to the decay of vacuum energy. We carry out a
joint statistical analysis of observational data from the new \emph{gold}
sample of 182 SNe Ia, recent estimates of the CMB shift parameter, and BAO
measurements from the SDSS to show that such models favor the decay of vacuum
only into the dark matter sector, and that the separately conserved baryons
cannot be neglected. In order to explore ways to more fundamentally motivated
models, we also derive a coupled scalar field version for this general class of
vacuum decay scenarios.Comment: 6 pages, 3 figures, LaTe
Co-operative experiments made by the Ohio Agricultural Students' Union in 1896
Caption title.Mode of access: Internet
Sugar beet investigations in 1897
Caption title.Mode of access: Internet
Reconstruction of multi-decadal groundwater level time-series using a lumped conceptual model
Multi-decadal groundwater level records, which provide information about long-term variability and trends, are relatively rare. Whilst a number of studies have sought to reconstruct river flow records, there have been few attempts to reconstruct groundwater level time-series over a number of decades. Using long rainfall and temperature records, we developed and applied a methodology to do this using a lumped conceptual model. We applied the model to six sites in the UK, in four different aquifers: Chalk, limestone, sandstone and Greensand. Acceptable models of observed monthly groundwater levels were generated at four of the sites, with maximum Nash–Sutcliffe Efficiency scores of between 0.84 and 0.93 over the calibration and evaluation periods, respectively. These four models were then used to reconstruct the monthly groundwater level time-series over approximately 60 years back to 1910. Uncertainty in the simulated levels associated with model parameters was assessed using the Generalized Likelihood Uncertainty Estimation method. Known historical droughts and wet period in the UK are clearly identifiable in the reconstructed levels, which were compared using the Standardized Groundwater Level Index. Such reconstructed records provide additional information with which to improve estimates of the frequency, severity and duration of groundwater level extremes and their spatial coherence, which for example is important for the assessment of the yield of boreholes during drought period
Groundwater drought forecasting using lumped conceptual models
For
fractured aquifers, such as the Cretaceous Chalk, autocorrelation
in SGI (Bloomfield & Marchant, 2013) has been inferred
to be primarily
related to autocorrelation in the recharge time series, while in granular
aquifers, such as the Permo–
Triassic sandstones, autocorrelation in
SGI is inferred to be primarily a function of intrinsic
saturated flow and
storage properties of aquife
Convergence and segregation of the multiple rod pathways in mammalian retina.
Using a multidisciplinary approach, we demonstrate that three different pathways are responsible for the transmission of rod signals across the mouse retina. Each pathway serves a primarily nonoverlapping range of stimulus intensities, with ganglion cells receiving either segregated or convergent inputs. For both on-center (ON) and off-center (OFF) ganglion cells, the primary rod pathway carries signals with the lowest threshold, whereas the secondary rod pathway is less sensitive by approximately 1 log unit. In addition, OFF signaling uses a tertiary rod pathway that is approximately 1 log unit less sensitive than the secondary. Although some ganglion cells received rod inputs exclusively from one of the pathways, others showed convergent inputs. Using pharmacological and genetic approaches, we defined classes of ON and OFF ganglion cells for which the scotopic inputs derive only from the primary pathway or from both primary and secondary pathways. In addition, we observed a class of OFF ganglion cell receiving mixed input from primary and tertiary pathways. Interestingly, OFF ganglion cells receiving convergent inputs from all three rod pathways or from the secondary and tertiary pathways together were never observed. Overall, our data show a complex arrangement of convergence and segregation of rod inputs to ganglion cells in the mammalian retina
Polyelectrolyte Bundles
Using extensive Molecular Dynamics simulations we study the behavior of
polyelectrolytes with hydrophobic side chains, which are known to form
cylindrical micelles in aqueous solution. We investigate the stability of such
bundles with respect to hydrophobicity, the strength of the electrostatic
interaction, and the bundle size. We show that for the parameter range relevant
for sulfonated poly-para-phenylenes (PPP) one finds a stable finite bundle
size. In a more generic model we also show the influence of the length of the
precursor oligomer on the stability of the bundles. We also point out that our
model has close similarities to DNA solutions with added condensing agents,
hinting to the possibility that the size of DNA aggregates is under certain
circumstances thermodynamically limited.Comment: 10 pages, 8 figure
Can Strong Gravitational Lensing Constrain Dark Energy?
We discuss the ratio of the angular diameter distances from the source to the
lens, , and to the observer at present, , for various dark
energy models. It is well known that the difference of s between the
models is apparent and this quantity is used for the analysis of Type Ia
supernovae. However we investigate the difference between the ratio of the
angular diameter distances for a cosmological constant,
and that for other dark energy models,
in this paper. It has been known that there is
lens model degeneracy in using strong gravitational lensing. Thus, we
investigate the model independent observable quantity, Einstein radius
(), which is proportional to both and velocity
dispersion squared, . values depend on the parameters
of each dark energy model individually. However, for the various dark energy models, is well within
the error of for most of the parameter spaces of the dark energy
models. Thus, a single strong gravitational lensing by use of the Einstein
radius may not be a proper method to investigate the property of dark energy.
However, better understanding to the mass profile of clusters in the future or
other methods related to arc statistics rather than the distances may be used
for constraints on dark energy.Comment: 15 pages, 13 figures, Accepted in PR
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Sub-seasonal forecasts of demand and wind power and solar power generation for 28 European countries
Electricity systems are becoming increasingly exposed to weather. The need for high-quality meteorological forecasts
for managing risk across all timescales has therefore never been greater. This paper seeks to extend the uptake of meteorological data in the power systems modelling community to include probabilistic meteorological forecasts at sub-seasonal lead-times. Such forecasts are growing in skill and are receiving considerable attention in power system risk management and energy trading. Despite this interest, these forecasts are rarely evaluated in power system terms and technical barriers frequently prohibit use by non-meteorological specialists.
This paper therefore presents data produced through a new EU climate services program Subseasonal-to-seasonal forecasting
for Energy (S2S4E). The data corresponds to a suite of well-documented, easy-to-use, self-consistent daily- and nationally aggregated time-series for wind power, solar power and electricity demand across 28 European countries. The data is accessible from http://dx.doi.org/10.17864/1947.275, (Gonzalez et al., 2020). The data includes a set of daily ensemble reforecasts from two leading forecast systems spanning 20-years (ECMWF, an 11 member ensemble, with twice weekly starts for 1996-2016, totalling 21,210 forecasts) and 11 years (NCEP, a 12 member lagged-ensemble, constructed to match the start dates from the ECMWF forecast. from 1999-2010, totalling 4608 forecasts). The reforecasts containing multiple plausible realisations of daily-weather and power data for up to 6 weeks in the future.
To the authors’ knowledge, this is the first time fully calibrated and post-processed daily power system forecast set has been published, and this is the primary purpose of this paper. A brief review of forecast skill in each of the individual primary power system properties and a composite property is presented, focusing on the winter season. The forecast systems contain additional skill over climatological expectation for weekly-average forecasts at extended lead-times, though this skill depends
on the nature of the forecast metric considered. This highlights the need for greater collaboration between the energy- and meteorological research communities to develop applications, and it is hoped that publishing these data and tools will support this
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