Prediction for Nonabelian Fine Structure Constants from Multicriticality

In developing a model for predicting the nonabelian gauge coupling constants we argue for the phenomenological validity of a ``principle of multiple point criticality''. This is supplemented with the assumption of an ``(grand) anti-unified'' gauge group $SMG^{N_{gen.}}\sim U(1)^{N_{gen.}}\times SU(2)^{N_{gen.}}\times SU(3)^{N_{gen.}}$ that, at the Planck scale, breaks down to the diagonal subgroup. Here $N_{gen}$ is the number of generations which is assumed to be 3. According to this ``multiple point criticality principle'', the Planck scale experimental couplings correspond to multiple point couplings of the bulk phase transition of a lattice gauge theory (with gauge group $SMG^{N_{gen.}}$). Predictions from this principle agree with running nonabelian couplings (after an extrapolation to the Planck scale using the assumption of a ``desert'') to an accuracy of 7\%. As an explanation for the existence of the multiple point, a speculative model using a glassy lattice gauge theory is presented.Comment: 42, NBI-HE-93-2

Quantum information cannot be split into complementary parts

We prove a new impossibility for quantum information (the no-splitting theorem): an unknown quantum bit (qubit) cannot be split into two complementary qubits. This impossibility, together with the no-cloning theorem, demonstrates that an unknown qubit state is a single entity, which cannot be cloned or split. This sheds new light on quantum computation and quantum information.Comment: 9 pages, 1 figur

Sustained MAPK/ERK activation in adult Schwann cells impairs nerve repair

The MAPK/ERK pathway has a critical role in PNS development. It is required for Schwann cell (SC) differentiation and myelination; sustained embryonic MAPK/ERK activation in SCs enhances myelin growth overcoming signals that normally end myelination. Excess activation of this pathway can be maladaptive as in adulthood acute strong activation of MAPK/ERK has been shown to cause SC dedifferentiation and demyelination. We used a mouse model (including male and female animals) in which gain of function Mek1DD allele produces sustained MAPK/ERK activation in adult SCs and we determined the impact of such activation on nerve repair. In the uninjured nerve, MAPK/ERK activation neither impaired myelin nor did it re-activate myelination. However, in the injured nerve it was detrimental and resulted in delayed repair and functional recovery. In the early phase of injury the rate of myelin clearance was faster. Four weeks following injury, when nerve repair is normally advanced, myelinated axons of Mek1DD mutants demonstrated higher rates of myelin decompaction, a reduced number of Cajal bands and decreased internodal length. We noted the presence of abnormal Remak bundles with long SCs processes and reduced numbers of C-fibres/Remak bundle. Both the total number of regenerating axons and the intra-epidermal nerve fibres density in the skin were reduced. Sustained activation of MAPK/ERK in adult SCs is therefore deleterious to successful nerve repair, emphasising the differences in the signalling processes coordinating nerve development and repair. Our results also underline the key role of SCs in axon regeneration and successful target einnervation.SIGNIFICANCE STATEMENTThe MAPK/ERK pathway promotes developmental myelination and its sustained activation in SCs induced continuous myelin growth, compensating for the absence of essential myelination signals. However, the strength of activation is fundamental because acute strong induction of MAPK/ERK in adulthood induces demyelination. What has been unknown is the effect of a mild but sustained MAPK/ERK activation in SCs on nerve repair in adulthood. This promoted myelin clearance but led to abnormalities in non-myelinating and myelinating SCs in the later phases of nerve repair, resulting in slowed axon regeneration, cutaneous reinnervation and functional recovery. Our results emphasise the distinct role of the MAPK/ERK pathway in developmental myelination versus remyelination and the importance of signalling between SCs and axons for successful axon regeneration

Austerity, poverty, and children's services quality in England : consequences for child welfare and public services

In England, the dominant policy narrative recognises no association between spending on children’s services and quality and a limited association between quality and deprivation. We combined 374 inspection outcomes between 2011 and 2019 with data on preventative and safeguarding expenditure and Indices of Multiple Deprivation (IMD) scores. A multilevel logistic regression model predicting ‘good’ or ‘outstanding’ judgements suggests each £100 increase in preventative spending per child was associated with a 69 per cent increase (95 per cent CI: 27.5 per cent, 124 per cent) in the odds of a positive inspection. A one-decile increase in deprivation was associated with a 16 per cent (95 per cent CI: −25 per cent, −5.7 per cent) decrease. Safeguarding expenditure was not associated with outcomes. Deprived communities have worse access to good-quality children’s services and government policies that have increased poverty and retrenched preventative services have likely exacerbated this inequality. Further, inattention to socioeconomic context in inspections raises concerns about their use in ‘take over’ policies

N-qubit entanglement via the Jy2J_y^2-type collective interaction

We investigate quantum correlations of the $N$-qubit states via a collective pseudo-spin interaction ($\propto J_y^2$) on arbitrary pure separable states for a given interval of time. Based on this dynamical generation of the $N$-qubit maximal entangled states, a quantum secret sharing protocol with $N$ continuous classical secrets is developed.Comment: 12 pages, 3 figure

Resting vs. active: a meta-analysis of the intra- and inter-specific associations between minimum, sustained, and maximum metabolic rates in vertebrates

Variation in aerobic capacity has far reaching consequences for the physiology, ecology, and evolution of vertebrates. Whether at rest or active, animals are constrained to operate within the energetic bounds determined by their minimum (minMR) and sustained or maximum metabolic rates (upperMR). MinMR and upperMR can differ considerably among individuals and species but are often presumed to be mechanistically linked to one another. Specifically, minMR is thought to reflect the idling cost of the machinery needed to support upperMR. However, previous analyses based on limited datasets have come to conflicting conclusions regarding the generality and strength of their association. Here we conduct the first comprehensive assessment of their relationship, based on a large number of published estimates of both the intra-specific (n = 176) and inter-specific (n = 41) phenotypic correlations between minMR and upperMR, estimated as either exercise-induced maximum metabolic rate (VO2max), cold-induced summit metabolic rate (Msum), or daily energy expenditure (DEE). Our meta-analysis shows that there is a general positive association between minMR and upperMR that is shared among vertebrate taxonomic classes. However, there was stronger evidence for intra-specific correlations between minMR and Msum and between minMR and DEE than there was for a correlation between minMR and VO2max across different taxa. As expected, inter-specific correlation estimates were consistently higher than intra-specific estimates across all traits and vertebrate classes. An interesting exception to this general trend was observed in mammals, which contrast with birds and exhibit no correlation between minMR and Msum. We speculate that this is due to the evolution and recruitment of brown fat as a thermogenic tissue, which illustrates how some species and lineages might circumvent this seemingly general association. We conclude that, in spite of some variability across taxa and traits, the contention that minMR and upperMR are positively correlated generally holds true both within and across vertebrate species. Ecological and comparative studies should therefore take into consideration the possibility that variation in any one of these traits might partly reflect correlated responses to selection on other metabolic parameters

Non-stoichiometric oxide and metal interfaces and reactions

We have employed a combination of experimental surface science techniques and density functional calculations to study the reduction of TiO2(110) surfaces through the doping with submonolayer transition metals. We concentrate on the role of Ti adatoms in self doping of rutile and contrast the behaviour to that of Cr. DFT+U calculations enable identification of probable adsorption structures and their spectroscopic characteristics. Adsorption of both metals leads to a broken symmetry and an asymmetric charge transfer localised around the defect site of a mixed localised/delocalised character. Charge transfer creates defect states with Ti 3d character in the band gap at similar to 1-eV binding energy. Cr adsorption, however, leads to a very large shift in the valence-band edge to higher binding energy and the creation of Cr 3d states at 2.8-eV binding energy. Low-temperature oxidation lifts the Ti-derived band-gap states and modifies the intensity of the Cr features, indicative of a change of oxidation state from Cr3+ to Cr4+. Higher temperature processing leads to a loss of Cr from the surface region, indicative of its substitution into the bulk

Entanglement, Mixedness, and Spin-Flip Symmetry in Multiple-Qubit Systems

A relationship between a recently introduced multipartite entanglement measure, state mixedness, and spin-flip symmetry is established for any finite number of qubits. It is also shown that, within those classes of states invariant under the spin-flip transformation, there is a complementarity relation between multipartite entanglement and mixedness. A number of example classes of multiple-qubit systems are studied in light of this relationship.Comment: To appear in Physical Review A; submitted 14 May 200

Can residuals of the Solar system foreground explain low multipole anomalies of the CMB ?

The low multipole anomalies of the Cosmic Microwave Background has received much attention during the last few years. It is still not ascertained whether these anomalies are indeed primordial or the result of systematics or foregrounds. An example of a foreground, which could generate some non-Gaussian and statistically anisotropic features at low multipole range, is the very symmetric Kuiper Belt in the outer solar system. In this paper, expanding upon the methods presented by Maris et al. (2011), we investigate the contributions from the Kuiper Belt objects (KBO) to the WMAP ILC 7 map, whereby we can minimize the contrast in power between even and odd multipoles in the CMB, discussed discussed by Kim & Naselsky (2010). We submit our KBO de-correlated CMB signal to several tests, to analyze its validity, and find that incorporation of the KBO emission can decrease the quadrupole-octupole alignment and parity asymmetry problems, provided that the KBO signals has a non-cosmological dipole modulation, associated with the statistical anisotropy of the ILC 7 map. Additionally, we show that the amplitude of the dipole modulation, within a 2 sigma interval, is in agreement with the corresponding amplitudes, discussed by Lew (2008).Comment: 24 pages, 9 figures, 5 tables. Matches version in JCA