Research note: The influence of micro-oxygenation on the long-term ageing ability of Pinot noir wine

In this study, Pinot noir wines were bottle aged for 12 and 18 months after micro-oxygenation (MOX) applied before or after malolactic fermentation (MLF) at two doses (10.8 and 52.4 mg/L/month). After ageing, a greater decrease in the total SO₂ concentration was found in wines with the higher MOX dosage, demonstrating a long-term impact of higher oxygen exposure on wines’ SO₂ requirement. Meanwhile, a negative impact of MOX on wine colour development occurred over time, resulting in a large loss of colour measures (i.e., 420 nm for brown hues, 520 nm for red colour, SO₂ resistant pigments, and colour intensity), which was greater with the early oxygen exposure. This was linked to a significantly lower content of large polymeric pigments in MOX treatments. Tannin concentration was, in the end, not affected by the MOX treatments. However, regarding tannin composition, considerably higher (-)-epicatechin extension units but much lower (-)-epicatechin terminal units were found with MOX treatments. In addition, a significant reduction of tannin trihydroxylation (%Tri-OH) but a higher galloylation (%Galloyl) and mean degree of tannin polymerisation (mDP) remained in wines with MOX, indicating a long-term negative influence on astringency intensity

Ultraspinning instability: the missing link

We study linearized perturbations of Myers-Perry black holes in d=7, with two of the three angular momenta set to be equal, and show that instabilities always appear before extremality. Analogous results are expected for all higher odd d. We determine numerically the stationary perturbations that mark the onset of instability for the modes that preserve the isometries of the background. The onset is continuously connected between the previously studied sectors of solutions with a single angular momentum and solutions with all angular momenta equal. This shows that the near-extremality instabilities are of the same nature as the ultraspinning instability of d>5 singly-spinning solutions, for which the angular momentum is unbounded. Our results raise the question of whether there are any extremal Myers-Perry black holes which are stable in d>5.Comment: 19 pages. 1 figur

D-brane Construction of the 5D NHEK Dual

Extremal but non-supersymmetric charged black holes with SU(2)_L spin in IIB string theory compactified to five dimensions on K^3 x S^1 are considered. These have a near-horizon or NHEK region with an enhanced SL(2,R)_L conformal symmetry. It is shown that the NHEK geometry has a second, inequivalent, asymptotically flat extension in which the radius of the S^1 becomes infinite but the radius of the angular circles of SU(2)_L orbits approach a constant. The asymptotic charges associated to the second solution identify it as a 5D D1-D5-Taub-NUT black string with certain nonzero worldvolume charge densities, temperatures and chemical potentials. The dual of the NHEK geometry is then identified as an IR limit of this wrapped brane configuration.Comment: 11 page

Conformal weights in the Kerr/CFT correspondence

It has been conjectured that a near-extreme Kerr black hole is described by a 2d CFT. Previous work has shown that CFT operators dual to axisymmetric gravitational perturbations have integer conformal weights. In this paper, we study the analogous problem in 5d. We consider the most general near-extreme vacuum black hole with two rotational symmetries. This includes Myers-Perry black holes, black rings and Kaluza-Klein black holes. We find that operators dual to gravitational (or electromagnetic or massless scalar field) perturbations preserving both rotational symmetries have integer conformal weights, the same for all black holes considered.Comment: 19 page

Different ontogenetic trajectories of body colour, pattern, and crypsis in two sympatric intertidal crab species

This is the author accepted manuscript. The final version is available from Oxford University Press via the DOI in this recordAnimals frequently exhibit high appearance variation, especially in heterogeneous habitats where individuals may be differentially concealed against backgrounds. While background matching is a common anti-predator strategy, gaps exist in understanding within- and among-species variation. Specifically, the drivers of appearance changes associated with habitat use and occurring through ontogeny are poorly understood. Using image analysis, we tested how individual appearance and camouflage in two intertidal crab species – the mud crab Panopeus americanus and the mottled crab Pachygrapsus transversus – relates to ontogeny and habitat use. We predicted that both species would change appearance with ontogeny, but resident mud crabs would exhibit higher background similarity than generalist mottled crabs. Both species showed ontogenetic changes, but while mud crabs become darker, mottled crabs turn greener. Small mud crabs were highly variable in colour and pattern, likely stemming from utilising camouflage in heterogeneous habitats during the most vulnerable life-stage. Being habitat specialists, mud crabs concealed better against all backgrounds than mottled crabs. Mottled crabs are motile and generalist, occupying macroalgal-covered rocks when adults, which explain why they are greener and why matches to specific habitats are less valuable. Differential habitat use in crabs can be associated with different coloration and camouflage strategies to avoid predation.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológic

Multi-black rings and the phase diagram of higher-dimensional black holes

Configurations of multiple concentric black rings play an important role in determining the pattern of branchings, connections and mergers between different phases of higher-dimensional black holes. We examine them using both approximate and (in five dimensions) exact methods. By identifying the role of the different scales in the system, we argue that it is possible to have multiple black ring configurations in which all the rings have equal temperature and angular velocity. This allows us to correct and improve in a simple, natural manner, an earlier proposal for the phase diagram of singly-rotating black holes in $D\geq 6$.Comment: 14 pages, 2 figure

Ultraspinning instability of anti-de Sitter black holes

Myers-Perry black holes with a single spin in d>5 have been shown to be unstable if rotating sufficiently rapidly. We extend the numerical analysis which allowed for that result to the asymptotically AdS case. We determine numerically the stationary perturbations that mark the onset of the instabilities for the modes that preserve the rotational symmetries of the background. The parameter space of solutions is thoroughly analysed, and the onset of the instabilities is obtained as a function of the cosmological constant. Each of these perturbations has been conjectured to represent a bifurcation point to a new phase of stationary AdS black holes, and this is consistent with our results.Comment: 22 pages, 7 figures. v2: Reference added. Matches published versio

Impact of microoxygenation on Pinot noir wines with different initial phenolic content

Microoxygenation (MOX) is used to improve wine colour and sensory quality; however, limited information is available for Pinot noir wines and wines with different initial phenolic content. In this study, MOX was applied to two Pinot noir wines, with either a low or a high phenolic content, at two doses (0.50 and 2.11 mg/L/day) for 14 days. With the sterile filtration applied, acetaldehyde formation during MOX was very low, supporting the influence of yeast on acetaldehyde production during MOX. The MOX dosage rate did not significantly affect colour development, while the Pinot noir wine with higher phenolics benefited more from MOX, significantly increasing colour intensity and SO₂ resistant (polymeric) pigments. However, these changes did not guarantee colour stability, as a final SO₂ addition (100 mg/L) largely erased the improvement to colour in all wines. This could be due to the lower acetaldehyde formation, thus less ethyl-bridged stable pigments resistant to SO₂ bleaching. MOX also decreased the flavan-3-ols and anthocyanin monomers, which differed between the two Pinot noir wines, reflecting the initial phenolic content. Lastly, MOX generally increased the measured tannin concentration and affected the proportion of tannin subunits, with a decrease in tannin mass conversion and proportion of (-)-epigallocatechin extension units. Some of these changes in phenolic compounds could potentially increase astringency, suggesting that MOX should be applied to Pinot noir and other low phenolic wines with caution

Thermodynamic instability of doubly spinning black objects

We investigate the thermodynamic stability of neutral black objects with (at least) two angular momenta. We use the quasilocal formalism to compute the grand canonical potential and show that the doubly spinning black ring is thermodynamically unstable. We consider the thermodynamic instabilities of ultra-spinning black objects and point out a subtle relation between the microcanonical and grand canonical ensembles. We also find the location of the black string/membrane phases of doubly spinning black objects.Comment: 25 pages, 7 figures v2: matches the published versio