3,027 research outputs found
Uneven onset and pace of ice-dynamical imbalance in the Amundsen Sea Embayment, West Antarctica
We combine measurements acquired by five satellite altimeter missions to obtain an uninterrupted record of ice-sheet elevation change over the Amundsen Sea Embayment, West Antarctica, since 1992. Using these data, we examine the onset of surface lowering arising through ice-dynamical imbalance, and the pace at which it has propagated inland, by tracking elevation changes along glacier flowlines. Surface lowering has spread slowest (<6 km/yr) along the Pope, Smith, and Kohler (PSK) Glaciers, due to their small extent. Pine Island Glacier (PIG) is characterized by a continuous inland spreading of surface lowering, notably fast at rates of 13 to 15 km/yr along tributaries draining the southeastern lobe, possibly due to basal conditions or tributary geometry. Surface lowering on Thwaites Glacier (THG) has been episodic, and has spread inland fastest (10 to 12 km/yr) along its central flowlines. The current episodes of surface lowering started approximately 10 yr before the first measurements on PSK, around 1990 on PIG, and around 2000 on THG. Ice-dynamical imbalance across the sector has therefore been uneven during the satellite record
Are heterotrophic and silica-rich eukaryotic microbes an important part of the lichen symbiosis?
We speculate that heterotrophic and/or silica-rich eukaryotic microorganisms maybe an important part of the lichen symbiosis. None of the very few studies of heterotrophic protists associated with lichens have considered the possibility that they may be of functional significance in the lichen symbiosis. Here we start to develop, currently speculative, theoretical ideas about their potential significance. For example, all the protist taxa identified in lichens we sampled in Ohio USA depend on silica for growth and construction of their cell walls, this could suggest that silica-rich lichen symbionts may be significant in the biogeochemistry of the lichen symbiosis. We also present arguments suggesting a role for protists
in nitrogen cycling within lichen thalli and a potential role in controlling bacterial populations associated with lichens. In this necessarily speculative paper we highlight areas for future research and how newer technologies may be useful for understanding the full suite of organisms involved in the lichen symbiosis.
Keywords: lichens; protists; symbiosis; testate amoebae; diatom; chrysophyt
Differences in the semantics of prosocial words: an exploration of compassion and kindness
The study of prosocial behaviour has accelerated greatly in the last 20 years. Researchers are exploring different domains of prosocial behaviour such as compassion, kindness, caring, cooperation, empathy, sympathy, love, altruism and morality. While these constructs can overlap, and are sometimes used interchangeably, they also have distinctive features that require careful elucidation. This paper discusses some of the controversies and complexities of describing different (prosocial) mental states, followed by a study investigating the differences between two related prosocial concepts: compassion and kindness. For the study, a scenario-based questionnaire was developed to assess the degree to which a student (N = 222) and a community (N = 112) sample judged scenarios in terms of compassion or kindness. Subsequently, participants rated emotions (e.g. sadness, anxiety, anger, disgust, joy) associated with each scenario. Both groups clearly distinguished kindness from compassion in the scenarios on the basis of suffering. In addition, participants rated compassion-based scenarios as significantly higher on sadness, anger, anxiety and disgust, whereas kindness-based scenarios had higher levels of joy. As a follow-up, a further sample (29 male, 63 female) also rated compassionate scenarios as involving significantly more suffering compared to the kindness scenarios. Although overlapping concepts, compassion and kindness are clearly understood as different processes with different foci, competencies and emotion textures. This has implications for research in prosocial behaviour, and the cultivation of kindness and compassion for psychotherapy and in general.N/
On a chain of harmonic and monogenic potentials in Euclidean half-space
In the framework of Clifford analysis, a chain of harmonic and monogenic potentials is constructed in the upper half of Euclidean space R^(m+1), including a higher dimensional generalization of the complex logarithmic function. Their distributional limits at the boundary R^(m) turn out to be well-known distributions such as the Dirac distribution, the Hilbert kernel, the fundamental solution of the Laplace and Dirac operators, the square root of the negative Laplace operator, and the like. It is shown how each of those potentials may be recovered from an adjacent kernel in the chain by an appropriate convolution with such a distributional limit
Avoidance as a strategy of (not) coping: qualitative interviews with carers of Huntington's Disease patients
Peer reviewedPublisher PD
Mechanical Stress Inference for Two Dimensional Cell Arrays
Many morphogenetic processes involve mechanical rearrangement of epithelial
tissues that is driven by precisely regulated cytoskeletal forces and cell
adhesion. The mechanical state of the cell and intercellular adhesion are not
only the targets of regulation, but are themselves likely signals that
coordinate developmental process. Yet, because it is difficult to directly
measure mechanical stress {\it in vivo} on sub-cellular scale, little is
understood about the role of mechanics of development. Here we present an
alternative approach which takes advantage of the recent progress in live
imaging of morphogenetic processes and uses computational analysis of high
resolution images of epithelial tissues to infer relative magnitude of forces
acting within and between cells. We model intracellular stress in terms of bulk
pressure and interfacial tension, allowing these parameters to vary from cell
to cell and from interface to interface. Assuming that epithelial cell layers
are close to mechanical equilibrium, we use the observed geometry of the two
dimensional cell array to infer interfacial tensions and intracellular
pressures. Here we present the mathematical formulation of the proposed
Mechanical Inverse method and apply it to the analysis of epithelial cell
layers observed at the onset of ventral furrow formation in the {\it
Drosophila} embryo and in the process of hair-cell determination in the avian
cochlea. The analysis reveals mechanical anisotropy in the former process and
mechanical heterogeneity, correlated with cell differentiation, in the latter
process. The method opens a way for quantitative and detailed experimental
tests of models of cell and tissue mechanics
Psychological and physiological effects of compassionate mind training: A pilot randomised controlled study
The development of the compassionate self, associated with practices such as slow and deeper breathing, compassionate voice tones and facial expressions and compassionate focusing is central to Compassion Focused Therapy. This study explores the impact of a two-week Compassionate Mind Training (CMT) program on emotional, self-evaluative and psychopathology measures and on heart rate variability (HRV). Participants (general population and college students) were randomly assigned to one of two conditions: CMT (n=56) and Wait-List Control (n=37). Participants in the CMTcondition were instructed to practice CMT exercises during two weeks. Self-report measures of compassion, positive affect, fears of compassion, self-criticism, shame, depression, anxiety and stress, and HRV were collected at pre and post intervention in both conditions. Compared to the control group, the experimental group showed significant increases in positive emotions, associated with feeling relaxed and also safe and content, but not activated; and in self-compassion, compassion for others and compassion from others. There were significant reductions in shame, self-criticism, fears of compassion, and stress. Only the experimental group reported significant improvement in HRV. Developing awareness of the evolved nature and inherent difficulties of our minds allied with practicing CMT exercises has beneficial effects on participants' psychological and physiological well-being.N/
Topology by Design in Magnetic nano-Materials: Artificial Spin Ice
Artificial Spin Ices are two dimensional arrays of magnetic, interacting
nano-structures whose geometry can be chosen at will, and whose elementary
degrees of freedom can be characterized directly. They were introduced at first
to study frustration in a controllable setting, to mimic the behavior of spin
ice rare earth pyrochlores, but at more useful temperature and field ranges and
with direct characterization, and to provide practical implementation to
celebrated, exactly solvable models of statistical mechanics previously devised
to gain an understanding of degenerate ensembles with residual entropy. With
the evolution of nano--fabrication and of experimental protocols it is now
possible to characterize the material in real-time, real-space, and to realize
virtually any geometry, for direct control over the collective dynamics. This
has recently opened a path toward the deliberate design of novel, exotic
states, not found in natural materials, and often characterized by topological
properties. Without any pretense of exhaustiveness, we will provide an
introduction to the material, the early works, and then, by reporting on more
recent results, we will proceed to describe the new direction, which includes
the design of desired topological states and their implications to kinetics.Comment: 29 pages, 13 figures, 116 references, Book Chapte
The development of compassionate engagement and action scales for self and others
Background Studies of the value of compassion on physical and mental health and social relationships have proliferated in the last 25 years. Although, there are several conceptualisations and measures of compassion, this study develops three new measures of compassion competencies derived from an evolutionary, motivational approach. The scales assess 1. the compassion we experience for others, 2. the compassion we experience from others, and 3. self-compassion based on a standard definition of compassion as a ‘sensitivity to suffering in self and others with a commitment to try to alleviate and prevent it’. We explored these in relationship to other compassion scales, self-criticism, depression, anxiety, stress and well-being. Methods Participants from three different countries (UK, Portugal and USA) completed a range of scales including compassion for others, self-compassion, self-criticism, shame, depression, anxiety and stress with the newly developed ‘The Compassionate Engagement and Actions’ scale. Results All three scales have good validity. Interestingly, we found that the three orientations of compassion are only moderately correlated to one another (r < .5). We also found that some elements of self-compassion (e.g., being sensitive to, and moved by one’s suffering) have a complex relationship with other attributes of compassion (e.g., empathy), and with depression, anxiety and stress. A path-analysis showed that self-compassion is a significant mediator of the association between self-reassurance and well-being, while self-criticism has a direct effect on depressive symptoms, not mediated by self-compassion. Discussion Compassion evolved from caring motivation and in humans is associated with a range of different socially intelligent competencies. Understanding how these competencies can be inhibited and facilitated is an important research endeavour. These new scales were designed to assess these competencies. Conclusions This is the first study to measure the three orientations of compassion derived from an evolutionary model of caring motivation with specified competencies. Our three new measures of compassion further indicate important complex relationships between different potentiation’s of compassion, well-being, and vulnerability to psychopathologies.N/
Mathematical modelling of polyamine metabolism in bloodstream-form trypanosoma brucei: An application to drug target identification
© 2013 Gu et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are creditedThis article has been made available through the Brunel Open Access Publishing Fund.We present the first computational kinetic model of polyamine metabolism in bloodstream-form Trypanosoma brucei, the causative agent of human African trypanosomiasis. We systematically extracted the polyamine pathway from the complete metabolic network while still maintaining the predictive capability of the pathway. The kinetic model is constructed on the basis of information gleaned from the experimental biology literature and defined as a set of ordinary differential equations. We applied Michaelis-Menten kinetics featuring regulatory factors to describe enzymatic activities that are well defined. Uncharacterised enzyme kinetics were approximated and justified with available physiological properties of the system. Optimisation-based dynamic simulations were performed to train the model with experimental data and inconsistent predictions prompted an iterative procedure of model refinement. Good agreement between simulation results and measured data reported in various experimental conditions shows that the model has good applicability in spite of there being gaps in the required data. With this kinetic model, the relative importance of the individual pathway enzymes was assessed. We observed that, at low-to-moderate levels of inhibition, enzymes catalysing reactions of de novo AdoMet (MAT) and ornithine production (OrnPt) have more efficient inhibitory effect on total trypanothione content in comparison to other enzymes in the pathway. In our model, prozyme and TSHSyn (the production catalyst of total trypanothione) were also found to exhibit potent control on total trypanothione content but only when they were strongly inhibited. Different chemotherapeutic strategies against T. brucei were investigated using this model and interruption of polyamine synthesis via joint inhibition of MAT or OrnPt together with other polyamine enzymes was identified as an optimal therapeutic strategy.The work was carried out under a PhD programme partly funded by Prof. Ray Welland, School of Computing Science, University of Glasgo
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