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

Biodiversity friendly landscapes

Building on some of Teja Tscharntke’s key papers we discuss a number of complexities of farming systems and agricultural landscapes that we believe should be included in future studies of production landscapes. We contend that transformation of modern agricultural landscapes to biodiversity-friendly ones needs a combination of farming on-field measures, land-use practices and landscape measures, but also policies supporting less intensive production. We argue that in future research, landscape ecologists should acknowledge the multiple values of biodiversity, and abandon using simple species richness indicators for those values. Ecologists should rather focus on understanding what species and their interactions are actually doing in production ecosystems. Some myths in landscape ecology, such as global food scarcity, land sparing, and intensive farming being the benchmark for sustainable food production, are rejected. We show that the global agricultural system is entrenched in a productivist narrative that hinders development of more sustainable production systems. In order to change current agricultural systems towards sustainable production and biodiversity-friendly landscapes, we need a broader perspective that incorporates knowledge and understanding of social-ecological systems and processes. We exemplify this with four future scenarios for Swedish food systems that in different ways are suggested to contribute to biodiversity goals, though perhaps not exactly via the biodiversity-friendly landscapes envisioned by Teja and many other ecologists

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

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

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