Null warped AdS in higher spin gravity

We equip three-dimensional spin-3 gravity in the principal embedding with a new set of boundary conditions that we call "asymptotically null warped AdS". We find a chiral copy of the Polyakov-Bershadsky algebra as asymptotic symmetry algebra, reminiscent of the situation in topologically massive gravity with strict null warped AdS boundary conditions. We prove the invertibility of the map between zuvielbein and metric variables and construct a global gauge transformation to half of AdS spin-3 gravity in the diagonal embedding. This explains why the theory is chiral and why the Polyakov-Bershadsky algebra arises. We then introduce chemical potentials, derive the entropy, free energy, and the holographic response functions, and conclude with a discussion

Lifshitz Holography with Isotropic Scale Invariance

Is it possible for an anisotropic Lifshitz critical point to actually exhibit isotropic conformal invariance? We answer this question in the affirmative by constructing a concrete holographic realization. We study three-dimensional spin-3 higher-spin gauge theory with a z=2 Lifshitz ground state with non-trivial spin-3 background. We provide consistent boundary conditions and determine the associated asymptotic symmetry algebra. Surprisingly, we find that the algebra consists of two copies of the W_3 extended conformal algebra, which is the extended conformal algebra of an isotropic critical system. Moreover, the central charges are given by 3l/(2G). We consider the possible geometric interpretation of the theory in light of the higher spin gauge invariance and remark on the implications of the asymptotic symmetry analysis.Comment: 19 pp; v2: minor edits, new refs; v3: added footnote, minor rewordings, to appear in JHE

The Safe-Asset Share

We document that the percentage of all U.S. assets that are “safe” has remained stable at about 33 percent since 1952. This stable ratio is a rare example of calm in a rapidly changing financial world. Over the same time period, the ratio of U.S. assets to GDP has increased by a factor of 2.5, and the main supplier of safe financial debt has shifted from commercial banks to the “shadow banking system.” We analyze this pattern of stylized facts and offer some tentative conclusions about the composition of the safe-asset share and its role within the overall economy.

Velocity moments of dark matter haloes

Using cosmological N-body simulations we study the line-of-sight velocity distribution of dark matter haloes focusing on the lowest-order even moments, dispersion and kurtosis, and their application to estimate the mass profiles of cosmological structures. For each of the ten massive haloes selected from the simulation box we determine the virial mass, concentration and the anisotropy parameter. In order to emulate observations from each halo we choose randomly 300 particles and project their velocities and positions along the line of sight and on the surface of the sky, respectively. After removing interlopers we calculate the profiles of the line-of-sight velocity moments and fit them with the solutions of the Jeans equations. The estimates of virial mass, concentration parameter and velocity anisotropy obtained in this way are in good agreement with the values found from the full 3D analysis.Comment: 2 pages, 1 figure, poster contribution to the proceedings of the XXIst IAP Colloquium "Mass Profiles and Shapes of Cosmological Structures", Paris 4-9 July 2005, Editors: G. Mamon, F. Combes, C. Deffayet, B. Fort, EDP Sciences, in pres

Radial velocity moments of dark matter haloes

Using cosmological N-body simulations we study the radial velocity distribution in dark matter haloes focusing on the lowest-order even moments, dispersion and kurtosis. We determine the properties of ten massive haloes in the simulation box approximating their density distribution by the NFW formula characterized by the virial mass and concentration. We also calculate the velocity anisotropy parameter of the haloes and find it mildly radial and increasing with distance from the halo centre. The radial velocity dispersion of the haloes shows a characteristic profile with a maximum, while the radial kurtosis profile decreases with distance starting from a value close to Gaussian near the centre. We therefore confirm that dark matter haloes possess intrinsically non-Gaussian, flat-topped velocity distributions. We find that the radial velocity moments of the simulated haloes are quite well reproduced by the solutions of the Jeans equations obtained for the halo parameters with the anisotropy measured in the simulations. We also study the radial velocity moments for a composite cluster made of ten haloes out to ten virial radii. In this region the velocity dispersion decreases systematically to reach the value of the background, while kurtosis increases from below to above the Gaussian value of 3 signifying a transition from a flat-topped to a strongly peaked velocity distribution with respect to the Gaussian, which can be interpreted as the dominance of ordered flow with a small dispersion. We illustrate the transition by showing explicitly the velocity distribution of the composite cluster in a few radial bins.Comment: 5 pages, 4 figures, minor changes, accepted for publication in MNRAS Letter

PALAEOECOLOGY, PALAEOENVIRONMENTAL ANALYSIS AND THEIR APPLICATION TO SEQUENCE STRATIGRAPHY: LOWER CRETACEOUS, LUSITANIAN BASIN, PORTUGAL

Palaeoecological data can provide key information on depositional environments. This may be critical to the interpretation of marine sedimentary cycles and the recognition of ancient cycles and sequences. Although many recent studies have attempted to combine palaeoecology and sequence stratigraphy, the sequence stratigraphic model is commonly used to provide a temporally constrained framework for the evaluation of ecological and evolutionary events. This study shows how palaeoecology can be used as a powerful tool in the development of sequence stratigraphic models. A palaeoecological study of three Lower Cretaceous successions (at Ericeira, Cascais, Cabo Espichel) from the southern part of the Lusitanian Basin, Portugal, provides a basis for this study. This palaeoecological analysis allowed the construction of a detailed picture of the effects of relative sea-level, and other environmental factors, on sedimentary succession evolution. The results of this palaeoecological analysis have been represented on a series of depositional facies trend diagrams. The depositional facies diagrams have then been used to develop the sequence stratigraphy of the southern part of the Lusitanian Basin. The study successions record the temporal changes, and along-strike variation, in the evolution of three mixed carbonate-siliciclastic systems. The base of all the successions represents the development of narrow shelf with minor wave reworking. Siliciclastics were introduced by sand and gravel-load river dominated deltas with little reworking of the sediment at the channel mouths. This was characterised by the development of a clastic beach-barrier at Ericeira and a 'cool-water' carbonate ramp at Cascais. At Cabo Espichel a coral biostrome developed where coral ecology was controlled by terrigenous sedimentation and turbidity. The upper part of the successions represent a change in the morphology of the basin. A broad, shallow, low energy carbonate shelf developed that dissipated wave energy. In the nearshore environment siliciclastics were prevalent. The shelf carbonates are characteristic of the 'cool-water' type carbonates of the Cretaceous Tethyan realm. The more proximal Ericeira and Cabo Espichel successions record the alternation between marginal marine siliciclastic and shallow-water marine carbonate environments. The Cascais succession is characterised by carbonate platforms with abundant coral and rudist bivalve faunas. Palaeoecological analysis and development of the depositional facies trend diagrams have allowed the identification of one mega-sequence (2nd order), six sequences (3rd order) and higher resolution sequences and parasequences (4th order). 2nd and 3rd order sequences are correlatable across the southern part of the Lusitanian Basin. They also correlate with previously published sequence chronostratigraphy for the Tethyan realm. The palaeoecological analysis indicates that 2nd and 3rd order sequences are controlled by allocyclic processes and that 4th order cycles (sequences and parasequences) were dominated by autocyclic processes. As a result 4th order cycles cannot be correlated across the basin. This study has shown that detailed palaeoecological analysis can reveal a detailed, and more accurate, picture of the controls on the development of a basin fill than sedimentology alone. Along with the depositional trend diagrams, these data can provide a powerful method for the development of a sequence stratigraphic model and aid to interpretation of a basin fill

Finding bridges in packings of colloidal spheres

We identify putative load-bearing structures (bridges) in experimental colloidal systems studied by confocal microscopy. Bridges are co-operative structures that have been used to explain stability and inhomogeneous force transmission in simulated granular packings with a range of densities. We show that bridges similar to those found in granular simulations are present in real experimental colloidal packings. We describe critically the bridge-finding procedure for real experimental data and propose a new criterion-Lowest Mean Squared Separation (LSQS)-for selecting optimum stabilisations

SLC6 neurotransmitter transporter family in GtoPdb v.2023.1

Members of the solute carrier family 6 (SLC6) of sodium- and (sometimes chloride-) dependent neurotransmitter transporters [32, 2, 23, 75] are primarily plasma membrane located and may be divided into four subfamilies that transport monoamines, GABA, glycine and neutral amino acids, plus the related bacterial NSS transporters [109]. The members of this superfamily share a structural motif of 10 TM segments that has been observed in crystal structures of the NSS bacterial homolog LeuTAa, a Na+-dependent amino acid transporter from Aquiflex aeolicus [137] and in several other transporter families structurally related to LeuT [49]

SLC6 neurotransmitter transporter family (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database

Members of the solute carrier family 6 (SLC6) of sodium- and (sometimes chloride-) dependent neurotransmitter transporters [29, 22, 70] are primarily plasma membrane located and may be divided into four subfamilies that transport monoamines, GABA, glycine and neutral amino acids, plus the related bacterial NSS transporters [99]. The members of this superfamily share a structural motif of 10 TM segments that has been observed in crystal structures of the NSS bacterial homolog LeuTAa, a Na+-dependent amino acid transporter from Aquiflex aeolicus [126] and in several other transporter families structurally related to LeuT [45]