317 research outputs found
First Occurrence of the Round Goby, Neogobius melanostomus, in the St. Lawrence River at Cornwall, Ontario
We document the first reported occurrence of the Round Goby, Neogobius melanostomus, a small benthic fish native to the Black and Caspian seas, in the St. Lawrence River near Cornwall. On 7 September 2004, we observed approximately 20 Round Gobies while SCUBA diving at a depth of 7 m, downstream of the Saunders Generating Station at Cornwall, Ontario. Round Gobies appear to have arrived recently in this reach of the river and have not previously been detected despite extensive fish surveys conducted in the area
Designing Markets for Biodiversity Offsets: Lessons from Tradable Pollution Permits
Globally, governments and regulators face an ongoing tradeâoff between meeting economic development needs and conserving biodiversity. Markets for biodiversity offsets are one tool which could secure biodiversity protection at lower costs to society whilst allowing some economic development to still take place. We provide a new perspective on biodiversity offset markets by focussing on what can be learnt from one of the bestâresearched environmental markets: the market for tradable pollution permits. We argue there are four key design parameters in terms of how and what to trade. These design parameters likely determine the ecological effectiveness and economic efficiency of any market in biodiversity offsets. Applying lessons from tradable pollution permit markets will be important if the benefits of biodiversity offset markets are to be realized more fully in future. A wellâfunctioning market for biodiversity offsets dually minimizes the economic costs of preventing future losses in biodiversity due to development and provides an economic incentive for landowners to invest in biodiversity conservation. The most crucial aspect of the market is what to trade (the currency in the offset market), and this has significant implications on the other key aspects of market design; the trading ratio which governs the rate of exchange between offsets at different points in space and time; the scale of the market; and how the market is regulated. We argue that markets function best where the conservation priority is a wellâdefined unit of biodiversity which can be readily measured and monitored. In situations where there are already strong regulations safeguarding biodiversity, the benefit of biodiversity offset markets is in reducing the aggregate costs of conservation. We believe biodiversity offset markets will offer the highest potential in developing countries with weaker environmental protection and a greater need to reconcile economic development needs with conservation under limited funding
Combined collider constraints on neutralinos and charginos
Searches for supersymmetric electroweakinos have entered a crucial phase, as
the integrated luminosity of the Large Hadron Collider is now high enough to
compensate for their weak production cross-sections. Working in a framework
where the neutralinos and charginos are the only light sparticles in the
Minimal Supersymmetric Standard Model, we use gambit to perform a detailed
likelihood analysis of the electroweakino sector. We focus on the impacts of
recent ATLAS and CMS searches with 36 fb of 13 TeV proton-proton
collision data. We also include constraints from LEP and invisible decays of
the and Higgs bosons. Under the background-only hypothesis, we show that
current LHC searches do not robustly exclude any range of neutralino or
chargino masses. However, a pattern of excesses in several LHC analyses points
towards a possible signal, with neutralino masses of = (8-155,
103-260, 130-473, 219-502) GeV and chargino masses of
= (104-259, 224-507) GeV
at the 95% confidence level. The lightest neutralino is mostly bino, with a
possible modest Higgsino or wino component. We find that this excess has a
combined local significance of , subject to a number of cautions. If
one includes LHC searches for charginos and neutralinos conducted with 8 TeV
proton-proton collision data, the local significance is lowered to 2.9.
We briefly consider the implications for dark matter, finding that the correct
relic density can be obtained through the Higgs-funnel and -funnel
mechanisms, even assuming that all other sparticles are decoupled. All samples,
gambit input files and best-fit models from this study are available on Zenodo.Comment: 38 pages, 16 figures, v3 is the version accepted by EPJ
Implications of the 125 GeV Higgs boson for scalar dark matter and for the CMSSM phenomenology
We study phenomenological implications of the ATLAS and CMS hint of a GeV Higgs boson for the singlet, and singlet plus doublet non-supersymmetric
dark matter models, and for the phenomenology of the CMSSM. We show that in
scalar dark matter models the vacuum stability bound on Higgs boson mass is
lower than in the standard model and the 125 GeV Higgs boson is consistent with
the models being valid up the GUT or Planck scale. We perform a detailed study
of the full CMSSM parameter space keeping the Higgs boson mass fixed to GeV, and study in detail the freeze-out processes that imply the observed
amount of dark matter. After imposing all phenomenological constraints except
for the muon we show that the CMSSM parameter space is divided
into well separated regions with distinctive but in general heavy sparticle
mass spectra. Imposing the constraint introduces severe tension
between the high SUSY scale and the experimental measurements -- only the
slepton co-annihilation region survives with potentially testable sparticle
masses at the LHC. In the latter case the spin-independent DM-nucleon
scattering cross section is predicted to be below detectable limit at the
XENON100 but might be of measurable magnitude in the general case of light dark
matter with large bino-higgsino mixing and unobservably large scalar masses.Comment: 17 pages, 7 figures. v3: same as published versio
Optical properties of LaNiO3 films tuned from compressive to tensile strain
Materials with strong electronic correlations host remarkable -- and
technologically relevant -- phenomena such as magnetism, superconductivity and
metal-insulator transitions. Harnessing and controlling these effects is a
major challenge, on which key advances are being made through lattice and
strain engineering in thin films and heterostructures, leveraging the complex
interplay between electronic and structural degrees of freedom. Here we show
that the electronic structure of LaNiO3 can be tuned by means of lattice
engineering. We use different substrates to induce compressive and tensile
biaxial epitaxial strain in LaNiO3 thin films. Our measurements reveal
systematic changes of the optical spectrum as a function of strain and,
notably, an increase of the low-frequency free carrier weight as tensile strain
is applied. Using density functional theory (DFT) calculations, we show that
this apparently counter-intuitive effect is due to a change of orientation of
the oxygen octahedra.The calculations also reveal drastic changes of the
electronic structure under strain, associated with a Fermi surface Lifshitz
transition. We provide an online applet to explore these effects. The
experimental value of integrated spectral weight below 2 eV is significantly
(up to a factor of 3) smaller than the DFT results, indicating a transfer of
spectral weight from the infrared to energies above 2 eV. The suppression of
the free carrier weight and the transfer of spectral weight to high energies
together indicate a correlation-induced band narrowing and free carrier mass
enhancement due to electronic correlations. Our findings provide a promising
avenue for the tuning and control of quantum materials employing lattice
engineering.Comment: 12 pages, 11 figure
Electrolyte measurements differ between point-of-care and reference analysers in dogs with hypoadrenocorticism
Introduction:
Dogs treated for hypoadrenocorticism are monitored through analysis of their blood electrolytes. This is routinely performed with pointâofâcare analysers and doses of medications are adjusted based on the results.
Objectives:
To investigate the performance of two pointâofâcare analysers (IDEXX Catalyst Dx and IDEXX VetStat) against a reference laboratory method for the measurement of blood sodium, potassium and chloride concentrations, as well as sodium: potassium ratios, in dogs diagnosed with and treated for hypoadrenocorticism.
Methods:
Fortyâeight dogs were enrolled into a prospective crossâsectional study. Paired blood samples were taken and tested on two pointâofâcare analysers and at a reference laboratory. Statistical analysis was then performed with BlandâAltman analysis and PassingâBablok regression. The clinical effects of inaccurate electrolyte analysis were investigated.
Results:
In total, 329 samples were tested on the Catalyst analyser, while another 72 samples were tested on the VetStat. PassingâBablok regression identified both proportional and constant bias for some analytes. There was poor agreement between sodium and chloride concentrations on both analysers. Both analysers tended to give higher results than the reference method for all analytes, except for potassium when measured on the VetStat.
Clinical Significance:
There are inherent differences between the electrolyte concentrations measured by these two pointâofâcare analysers and reference laboratory methods in dogs with hypoadrenocorticism
Intrinsic magnetism in superconducting infinite-layer nickelates
The discovery of superconductivity in NdSrNiO [1]
introduced a new family of layered nickelate superconductors that has now been
extended to include a range of Sr-doping [2, 3], Pr or La in place of Nd [4-6],
and the 5-layer NdNiO [7]. A number of studies indicate that
electron correlations are strong in these materials [8-14], and hence a central
question is whether or not magnetism is present as a consequence of these
interactions. Here we report muon spin rotation/relaxation studies of a series
of superconducting infinite-layer nickelates. In all cases we observe an
intrinsic magnetic ground state, regardless of the rare earth ion or doping,
arising from local moments on the nickel sublattice. The coexistence of
magnetism - which is likely to be antiferromagnetic and short-range ordered -
with superconductivity is reminiscent of some iron pnictides [15] and heavy
fermion compounds [16], and qualitatively distinct from the doped cuprates
[17]
The impact of XENON100 and the LHC on Supersymmetric Dark Matter
The effect of 2010 and 2011 LHC data are discussed in connection to the
potential for the direct detection of supersymmetric dark matter. The impact of
the recent XENON100 results are contrasted to these predictions.Comment: 14 pages, 23 figures, To be published in the Proceedings of the 7th
DSU Conference, Beijing Chin
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