Antagonism of detomidine with tolazoline in isoflurane-anaesthetised ponies

The effects of tolazoline (4.0 mg/kg iv) antagonism of detomidine (0.02 mg/kg iv) were evaluated in isoflurane-anaesthetised, ventilated ponies. Each of 6 ponies received both tolazoline and saline treatment during separate anaesthetic episodes only (no surgery was performed). Detomidine administration produced an increase in blood pressure, decrease in heart rate and decrease in P_aO₂ Tolazoline treatment transiently increased heart rate while blood pressure returned to baseline after both treatments. Arterial oxygenation decreased further after tolazoline treatment while oxgenation recovered towards baseline with saline treatment. No other cardiopulmonary effects were detected. Recovery from anaesthesia tended to be more rapid when detomidine was antagonized. The potential benefit of antagonizing detomidine-induced bradycardia with tolazoline, during isoflurane anaesthesia should be weighed against the potential to produce a decrease in arterial oxygenation. The mechanism for this effect is not clear.     

Visceral mast cell tumour with eosinophilia and eosinophilic peritoneal and pleural effusions in a cat

Summary A cat with weight loss, pyrexia and recurrent lethargy and depression was found to have pleural and peritoneal eosinophilic effusions, peripheral eosinophilia, eosinophilic lymphadenitis and a massively enlarged mesenteric lymph node. Visceral mast cell neoplasia was diagnosed after histopathological examination of a biopsy of the mass. Palliative chemotherapy was attempted unsuccessfully and the cat was euthanased.     

Biomimetic Pathways for Assembling Inorganic Thin Films

Living organisms construct various forms of laminated nanocomposites through directed nucleation and growth of inorganics at self-assembled organic templates at temperatures below 100°C and in aqueous solutions. Recent research has focused on the use of functionalized organic surfaces to form continuous thin films of single-phase ceramics. Continuous thin films of mesostructured silicates have also been formed on hydrophobic and hydrophilic surfaces through a two-step mechanism. First, under acidic conditions, surfactant micellar structures are self-assembled at the solid/liquid interface, and second, inorganic precursors condense to form an inorganic-organic nanocomposite. Epitaxial coordination of adsorbed surfactant tubules is observed on mica and graphite substrates, whereas a random arrangement is observed on amorphous silica. The ability to process ceramic-organic nanocomposite films by these methods provides new technological opportunities.     

The Seismic Structure of the Sun

Global Oscillation Network Group data reveal that the internal structure of the sun can be well represented by a calibrated standard model. However, immediately beneath the convection zone and at the edge of the energy-generating core, the sound-speed variation is somewhat smoother in the sun than it is in the model. This could be a consequence of chemical inhomogeneity that is too severe in the model, perhaps owing to inaccurate modeling of gravitational settling or to neglected macroscopic motion that may be present in the sun. Accurate knowledge of the sun's structure enables inferences to be made about the physics that controls the sun; for example, through the opacity, the equation of state, or wave motion. Those inferences can then be used elsewhere in astrophysics.     

Could recent increases in atmospheric CO2 have acted as a selection factor in Avena fatua populations? A case study of cultivated and wild oat competition

Projected increases in atmospheric carbon dioxide concentration [CO₂] may lead to differential selection and competition between weeds and crops. Yet, the current level of atmospheric [CO₂] already reflects a rapid rise (~25%) from mid‐20th century levels. To assess whether this increase could have already resulted in differential selection between weeds and crops, two temporally distinct populations of Avena fatua (wild oat) from the same geographic location, one from the 1960s (WO_old) and one from 2014 (WO_new), were grown with and without a cultivated oat (CO) line, Clintland 64 (Avena sativa) at current and mid‐20th century [CO₂] levels (ca 320 and 402 μmol mol^?1 respectively). Monocultures of each WO population differed in their response to recent increases in atmospheric [CO₂], with WO_new showing a significantly higher response for all vegetative parameters relative to WO_old. Assessment of competitive outcomes indicated that at 315 μmol mol^?1 cultivated oat was at a competitive advantage relative to either A. fatua population for leaf area and total above‐ground biomass. However, at current levels of CO₂, an overall increase in WO_new competitive ability was observed relative to the cultivated oat line. Overall, these differences are consistent with, but not conclusive for, improved evolutionary fitness and increased early competitive ability of A. fatua relative to cultivated oat as a function of the recent increase in atmospheric [CO₂]. While additional empirical studies are needed, these preliminary results indicate that weeds may be adapting rapidly to rising levels of atmospheric carbon dioxide.     

Evidence for recent evolution in an invasive species,Microstegium vimineum,Japanese stiltgrass

The establishment and spread of invasive plants are often associated with a ‘general‐purpose genotype’, with a corresponding high degree of phenotypic plasticity when introduced to a new environment. Evolutionary potential of invasive species following introduction should also be considered, however, as such changes can facilitate rapid range expansion. In this study, we utilised seed from three geographically distinct mid‐Atlantic populations of an invasive species, Microstegium vimineum (Japanese stiltgrass), to assess whether populations varied in their biomass and reproductive responses to light and nitrogen under neutral glasshouse conditions. To assess evolutionary adaptation, we quantified and correlated the abiotic environment from each collection location with the final biomass and seed production of that population under common glasshouse conditions. For M. vimineum, growth and reproductive responses to a common set of abiotic parameters (e.g. light) under these conditions indicated considerable phenotypic variation between and within populations. Interestingly, the degree of variation of seed production and final biomass among populations in the glasshouse was strongly correlated with growing season length and cumulative degree days recorded near each population location. These latter data indicated that M. vimineum, introduced into this region <100 years ago, may be undergoing adaptive evolution. Although additional populations of M. vimineum need to be examined, this study suggests that local evolutionary adaptation may be occurring rapidly and could, potentially, be an important aspect in the establishment and spread of this invasive species.     

Hydrogen radicals, nitrogen radicals, and the production of O3 in the upper troposphere

The concentrations of the hydrogen radicals OH and HO2 in the middle and upper troposphere were measured simultaneously with those of NO, O3, CO, H2O, CH4, non-methane hydrocarbons, and with the ultraviolet and visible radiation field. The data allow a direct examination of the processes that produce O3 in this region of the atmosphere. Comparison of the measured concentrations of OH and HO2 with calculations based on their production from water vapor, ozone, and methane demonstrate that these sources are insufficient to explain the observed radical concentrations in the upper troposphere. The photolysis of carbonyl and peroxide compounds transported to this region from the lower troposphere may provide the source of HOx required to sustain the measured abundances of these radical species. The mechanism by which NO affects the production of O3 is also illustrated by the measurements. In the upper tropospheric air masses sampled, the production rate for ozone (determined from the measured concentrations of HO2 and NO) is calculated to be about 1 part per billion by volume each day. This production rate is faster than previously thought and implies that anthropogenic activities that add NO to the upper troposphere, such as biomass burning and aviation, will lead to production of more O3 than expected.     

A tunable kondo effect in quantum dots

A tunable Kondo effect has been realized in small quantum dots. A dot can be switched from a Kondo system to a non-Kondo system as the number of electrons on the dot is changed from odd to even. The Kondo temperature can be tuned by means of a gate voltage as a single-particle energy state nears the Fermi energy. Measurements of the temperature and magnetic field dependence of a Coulomb-blockaded dot show good agreement with predictions of both equilibrium and nonequilibrium Kondo effects.