Modelling Sulphur Clusters for an Understanding of Ultramarine

Ultramarine pigments are aluminosilicate-based and contain sulphur-based chromophores. Self-consistent-field Hartree-Fock and Møller-Plesset second order perturbation theory were applied to determine the relative stability of S2, S2 –., S2 2–, and S3, S3 –., S3 2–. The singly charged species was found to be the most stable in both sets. The transition from green to blue ultramarine is thought to be the transformation of the doubly charged species to the singly charged species and is known to be exothermic. Modelling studies supported this hypothesis. The open,C2v, isomer was found to be the most stable for the S3 –. molecule, which is the blue chromophore in ultramarine. The closed, D3h, geometry represents a transition state. The S4 molecule is the most likely chromophore in ultramarine red; however the specific isomer is uncertain. Under the assumption that S4 was formed by a concerted reaction between S3 –. and S+., aWoodward-Hoffmann analysis of the molecular orbitals of S3 –. and S+. supported the formation of the puckered square S4, pyramidal S4, double triangle S4, and gauche S4 chain isomers. The gauche S4 chain is the most likely isomer in ultramarine red.Keywords: Ultramarine pigments, Woodward-Hoffmann analysis, modelling

On Finding Maximum Cardinality Subset of Vectors with a Constraint on Normalized Squared Length of Vectors Sum

In this paper, we consider the problem of finding a maximum cardinality subset of vectors, given a constraint on the normalized squared length of vectors sum. This problem is closely related to Problem 1 from (Eremeev, Kel'manov, Pyatkin, 2016). The main difference consists in swapping the constraint with the optimization criterion. We prove that the problem is NP-hard even in terms of finding a feasible solution. An exact algorithm for solving this problem is proposed. The algorithm has a pseudo-polynomial time complexity in the special case of the problem, where the dimension of the space is bounded from above by a constant and the input data are integer. A computational experiment is carried out, where the proposed algorithm is compared to COINBONMIN solver, applied to a mixed integer quadratic programming formulation of the problem. The results of the experiment indicate superiority of the proposed algorithm when the dimension of Euclidean space is low, while the COINBONMIN has an advantage for larger dimensions.Comment: To appear in Proceedings of the 6th International Conference on Analysis of Images, Social Networks, and Texts (AIST'2017

People with higher interoceptive sensitivity are more altruistic, but improving interoception does not increase altruism

People consistently show preferences and behaviors that benefit others at a cost to themselves, a phenomenon termed altruism. We investigated if perception of one’s body signals – interoception - may be underlying such behaviors. We tested if participants’ sensitivity to their own heartbeat predicted their decision on a choice between self-interest and altruism, and if improving this sensitivity through training would make participants more altruistic. Across these two experiments, interoceptive sensitivity predicted altruism measured through monetary generosity. Improving interoceptive sensitivity did, however, not lead to more altruistic behaviour. We conclude that there is a unique link between interoception and altruistic behaviour, likely established over an individual’s history of altruistic acts, and the body responses they elicit. The findings suggest that humans might literally ‘listen to their heart’ to guide their altruistic behavior

Larger than Life: Humans' Nonverbal Status Cues Alter Perceived Size

Social dominance and physical size are closely linked. Nonverbal dominance displays in many non-human species are known to increase the displayer's apparent size. Humans also employ a variety of nonverbal cues that increase apparent status, but it is not yet known whether these cues function via a similar mechanism: by increasing the displayer's apparent size.We generated stimuli in which actors displayed high status, neutral, or low status cues that were drawn from the findings of a recent meta-analysis. We then conducted four studies that indicated that nonverbal cues that increase apparent status do so by increasing the perceived size of the displayer. Experiment 1 demonstrated that nonverbal status cues affect perceivers' judgments of physical size. The results of Experiment 2 showed that altering simple perceptual cues can affect judgments of both size and perceived status. Experiment 3 used objective measurements to demonstrate that status cues change targets' apparent size in the two-dimensional plane visible to a perceiver, and Experiment 4 showed that changes in perceived size mediate changes in perceived status, and that the cue most associated with this phenomenon is postural openness.We conclude that nonverbal cues associated with social dominance also affect the perceived size of the displayer. This suggests that certain nonverbal dominance cues in humans may function as they do in other species: by creating the appearance of changes in physical size

Large herbivores may alter vegetation structure of semi-arid savannas through soil nutrient mediation

In savannas, the tree–grass balance is governed by water, nutrients, fire and herbivory, and their interactions. We studied the hypothesis that herbivores indirectly affect vegetation structure by changing the availability of soil nutrients, which, in turn, alters the competition between trees and grasses. Nine abandoned livestock holding-pen areas (kraals), enriched by dung and urine, were contrasted with nearby control sites in a semi-arid savanna. About 40 years after abandonment, kraal sites still showed high soil concentrations of inorganic N, extractable P, K, Ca and Mg compared to controls. Kraals also had a high plant production potential and offered high quality forage. The intense grazing and high herbivore dung and urine deposition rates in kraals fit the accelerated nutrient cycling model described for fertile systems elsewhere. Data of a concurrent experiment also showed that bush-cleared patches resulted in an increase in impala dung deposition, probably because impala preferred open sites to avoid predation. Kraal sites had very low tree densities compared to control sites, thus the high impala dung deposition rates here may be in part driven by the open structure of kraal sites, which may explain the persistence of nutrients in kraals. Experiments indicated that tree seedlings were increasingly constrained when competing with grasses under fertile conditions, which might explain the low tree recruitment observed in kraals. In conclusion, large herbivores may indirectly keep existing nutrient hotspots such as abandoned kraals structurally open by maintaining a high local soil fertility, which, in turn, constrains woody recruitment in a negative feedback loop. The maintenance of nutrient hotspots such as abandoned kraals by herbivores contributes to the structural heterogeneity of nutrient-poor savanna vegetation

Total ankle prostheses in rheumatoid arthropathy: Outcome in 52 patients followed for 1–9 years

Background and purpose The first generations of total ankle replacements (TARs) showed a high rate of early failure. In the last decades, much progress has been made in the development of TARs, with the newer generation showing better results. We evaluated TARs implanted with rheumatoid arthritis (RA) or juvenile inflammatory arthritis (JIA) as indication

Deguelin Attenuates Reperfusion Injury and Improves Outcome after Orthotopic Lung Transplantation in the Rat

The main goal of adequate organ preservation is to avoid further cellular metabolism during the phase of ischemia. However, modern preservation solutions do rarely achieve this target. In donor organs hypoxia and ischemia induce a broad spectrum of pathologic molecular mechanisms favoring primary graft dysfunction (PGD) after transplantation. Increased hypoxia-induced transcriptional activity leads to increased vascular permeability which in turn is the soil of a reperfusion edema and the enhancement of a pro-inflammatory response in the graft after reperfusion. We hypothesize that inhibition of the respiration chain in mitochondria and thus inhibition of the hypoxia induced mechanisms might reduce reperfusion edema and consecutively improve survival in vivo. In this study we demonstrate that the rotenoid Deguelin reduces the expression of hypoxia induced target genes, and especially VEGF-A, dose-dependently in hypoxic human lung derived cells. Furthermore, Deguelin significantly suppresses the mRNA expression of the HIF target genes VEGF-A, the pro-inflammatory CXCR4 and ICAM-1 in ischemic lungs vs. control lungs. After lung transplantation, the VEGF-A induced reperfusion-edema is significantly lower in Deguelin-treated animals than in controls. Deguelin-treated rats exhibit a significantly increased survival-rate after transplantation. Additionally, a downregulation of the pro-inflammatory molecules ICAM-1 and CXCR4 and an increase in the recruitment of immunomodulatory monocytes (CD163+ and CD68+) to the transplanted organ involving the IL4 pathway was observed. Therefore, we conclude that ischemic periods preceding reperfusion are mainly responsible for the increased vascular permeability via upregulation of VEGF. Together with this, the resulting endothelial dysfunction also enhances inflammation and consequently lung dysfunction. Deguelin significantly decreases a VEGF-A induced reperfusion edema, induces the recruitment of immunomodulatory monocytes and thus improves organ function and survival after lung transplantation by interfering with hypoxia induced signaling

Determinants of woody encroachment and cover in African savannas

Savanna ecosystems are an integral part of the African landscape and sustain the livelihoods of millions of people. Woody encroachment in savannas is a widespread phenomenon but its causes are widely debated. We review the extensive literature on woody encroachment to help improve understanding of the possible causes and to highlight where and how future scientific efforts to fully understand these causes should be focused. Rainfall is the most important determinant of maximum woody cover across Africa, but fire and herbivory interact to reduce woody cover below the maximum at many locations. We postulate that woody encroachment is most likely driven by CO2 enrichment and propose a two-system conceptual framework, whereby mechanisms of woody encroachment differ depending on whether the savanna is a wet or dry system. In dry savannas, the increased water-use efficiency in plants relaxes precipitation-driven constraints and increases woody growth. In wet savannas, the increase of carbon allocation to tree roots results in faster recovery rates after disturbance and a greater likelihood of reaching sexual maturity. Our proposed framework can be tested using a mixture of experimental and earth observational techniques. At a local level, changes in precipitation, burning regimes or herbivory could be driving woody encroachment, but are unlikely to be the explanation of this continent-wide phenomenon