Thermodynamic Metrics and Black Hole Physics

We give a brief survey of thermodynamic metrics, in particular the Hessian of the entropy function, and how they apply to black hole thermodynamics. We then provide a detailed discussion of the Gibbs surface of Kerr black holes. In particular we analyze its global properties, and extend it to take the entropy of the inner horizon into account. A brief discussion of Kerr-Newman black holes is included.Comment: 21 pages, new figures adde

Unextendible product bases and extremal density matrices with positive partial transpose

In bipartite quantum systems of dimension 3x3 entangled states that are positive under partial transposition (PPT) can be constructed with the use of unextendible product bases (UPB). As discussed in a previous publication all the lowest rank entangled PPT states of this system seem to be equivalent, under special linear product transformations, to states that are constructed in this way. Here we consider a possible generalization of the UPB constuction to low-rank entangled PPT states in higher dimensions. The idea is to give up the condition of orthogonality of the product vectors, while keeping the relation between the density matrix and the projection on the subspace defined by the UPB. We examine first this generalization for the 3x3 system where numerical studies indicate that one-parameter families of such generalized states can be found. Similar numerical searches in higher dimensional systems show the presence of extremal PPT states of similar form. Based on these results we suggest that the UPB construction of the lowest rank entangled states in the 3x3 system can be generalized to higher dimensions, with the use of non-orthogonal UPBs.Comment: 23 pages, 2 figures, 1 table. V2: Fixed fig.1 not showin

The monomial representations of the Clifford group

We show that the Clifford group - the normaliser of the Weyl-Heisenberg group - can be represented by monomial phase-permutation matrices if and only if the dimension is a square number. This simplifies expressions for SIC vectors, and has other applications to SICs and to Mutually Unbiased Bases. Exact solutions for SICs in dimension 16 are presented for the first time.Comment: Additional author and exact solutions to the SIC problem in dimension 16 adde

Antibodies to Tamm-Horsfall protein associated with renal damage and urinary tract infections in adults

Autoantibodies to Tamm-Horsfall protein associated with renal damage and urinary tract infections in adults. Forty-seven adults with urinary tract infection (UTI), 9 with recent acute pyelonephritis and 38 with previous renal infection, were investigated for the presence of autoantibodies to Tamm-Horsfall protein (THP). All patients except 6 had or had had vesicoureteric reflux (VUR). In patients with recent acute pyelonephritis, only IgA antibodies were significantly elevated. Among the patients with previous UTI, more than 6 months before the time of testing, a graded response was found for IgG and IgM specific antibodies, with the lowest value in those with renal damage and elevated serum creatinine and the highest in those with a normal X-ray. A negative correlation was found between IgG antibodies to THP and elevated serum creatinine (r = -0.76, P < 0.02). No significant correlation was found between VUR itself and antibodies to THP. A low IgG antibody level to THP in patients with a history of previous UTI seems to be a useful indicator of renal scarring. Possible immunologic mechanisms behind the low antibody level and the renal damage are discussed.Auto-anticorps anti-protéine de Tamm-Horsfall associés à des lésions rénales et à des infections urinaires chez l'adulte Quarante-sept adultes atteints d'infection urinaire, 9 ayant une pyélonéphrite aiguë récente et 38 une infection rénale antérieure ont été étudiés pour la présence d'auto-anticorps anti-protéine de Tamm-Horsfall (THP). Tous les malades sauf six avaient ou avaient eu un reflux vésico-urétéral. Chez les malades ayant un antécédent récent de pyélonéphrite seul les anti-corps IgA étaient significativement élevés. Parmi les malades dont l'antécédent d'infection urinaire remontait à plus de six mois une réponse a été obtenue pour les anti-corps spécifiques IgG et IgM, avec la valeur la plus faible chez ceux qui étaient atteints de lésions rénales et avaient une créatininémie élevée et la valeur la plus élevée chez ceux qui étaient indemnes de lésions radiologiques. Une corrélation négative a été observée entre les anti-corps IgG anti THP et l'augmentation de la créatininémie (r = -0,76, P < 0,02). Il n'a pas été observé de corrélation significative entre le reflux par lui-même et les anti-corps anti THP. Un taux faible d'anti-corps IgG anti THP chez des malades ayant des antécédents d'infection urinaire peut être un indicateur utile de lésions rénales. Les mécanismes immunologiques qui peuvent sous tendre le taux faible d'anti-corps et les lésions rénales sont discutés

Biotic interactions with mycorrhizal systems as extended nutrient acquisition strategies shaping forest soil communities and functions

Plant nutrient acquisition strategies involving ectomycorrhizal (EcM) and arbuscular mycorrhizal (AM) associations, are key plant functional traits leading to distinct carbon (C) and nutrient dynamics in forests. Yet, little is known about how these strategies influence the structure and functioning of soil communities, and if such mycorrhizal effects may be more or less pronounced depending on the type of forest and various abiotic factors. Here we explore the potential interactions occurring between plant-EcM and plant-AM systems with the diverse soil organisms occurring in forest soils, and in the process draw attention to major issues that are worthy for future research directions. Based on these potential interactions, we suggest that EcM systems, especially those involving gymnosperms in colder climates, may select for a soil community with a narrow set of functions. These EcM systems may exhibit low functional redundancy, dominated by symbiotic interactions, where EcM fungi maintain low pH and high C/N conditions in order to tightly control nutrient cycling and maintain the dominance of EcM trees. By contrast, AM systems, particularly those involving deciduous angiosperm trees in mild and warmer climates, may facilitate a functionally more diverse and redundant soil community tending towards the dominance of competitive and antagonistic interactions, but also with a range of symbiotic interactions that together maintain diverse plant communities. We propose that the contrasting belowground interactions in AM and EcM systems act as extended nutrient acquisition traits that contribute greatly to the prevailing nutrient and C dynamics occurring in these systems

Small-scale Collembola community composition in a pine forest soil - Overdispersion in functional traits indicates the importance of species interactions

Soil communities are considered to be remarkably species-rich and to have many generalist species with seemingly similar niche requirements. The composition of soil fauna communities is often highly variable even at the plot scale, and both the environment and the spatial configuration of microhabitats are regarded as important forces shaping the structure of local communities. However, to what extent these forces are important in different ecosystems is not clear. We examined the relative roles of environmental (abiotic), vegetation (biotic) and spatial variables (using Moran's eigenvector maps, MEM) for the small-scale variation in springtail (Collembola) communities in a 100 m(2) area of the forest floor of a mature Scots pine forest in central Sweden, with small variation in important environmental variables.We found that most of the small-scale variation in community composition could be explained by spatial variables, either alone or jointly with the environmental variables. Spatial variability in community composition, in turn, could be related to shifts in functional traits of the component species. Within local communities (samples), species showed a higher diversity than expected by chance in almost all examined traits, indicating that differences in resource and micro-habitat utilisation enable Collembola species to coexist. Competition between species is therefore likely to be important for structuring Collembola communities at this spatial scale. The results indicate that the spatial scale of study and heterogeneity of environmental factors influence soil fauna community assembly processes through effects on the relative importance of environmental filtering compared to filtering by limiting similarity or competitive exclusion. (C) 2016 The Authors. Published by Elsevier Ltd