The water footprint of cotton consumption

The consumption of a cotton product is connected to a chain of impacts on the water resources in the countries where cotton is grown and processed. The aim of this report is to assess the ‘water footprint’ of worldwide cotton consumption, identifying both the location and the character of the impacts. The study distinguishes between three types of impact: evaporation of infiltrated rainwater for cotton growth (green water use), withdrawal of ground- or surface water for irrigation or processing (blue water use) and water pollution during growth or processing. The latter impact is quantified in terms of the dilution volume necessary to assimilate the pollution. For the period 1997-2001 the study shows that the worldwide consumption of cotton products requires 256 Gm3 of water per year, out of which about 42% is blue water, 39% green water and 19% dilution water. Impacts are typically cross-border. About 84% of the water footprint of cotton consumption in the EU25 region is located outside Europe, with major impacts particularly in India and Uzbekistan. Given the general lack of proper water pricing mechanisms or other ways of transmitting production-information, cotton consumers have little incentive to take responsibility for the impacts on remote water systems

Magnetism, FeS colloids, and Origins of Life

A number of features of living systems: reversible interactions and weak bonds underlying motor-dynamics; gel-sol transitions; cellular connected fractal organization; asymmetry in interactions and organization; quantum coherent phenomena; to name some, can have a natural accounting via $physical$ interactions, which we therefore seek to incorporate by expanding the horizons of `chemistry-only' approaches to the origins of life. It is suggested that the magnetic 'face' of the minerals from the inorganic world, recognized to have played a pivotal role in initiating Life, may throw light on some of these issues. A magnetic environment in the form of rocks in the Hadean Ocean could have enabled the accretion and therefore an ordered confinement of super-paramagnetic colloids within a structured phase. A moderate H-field can help magnetic nano-particles to not only overcome thermal fluctuations but also harness them. Such controlled dynamics brings in the possibility of accessing quantum effects, which together with frustrations in magnetic ordering and hysteresis (a natural mechanism for a primitive memory) could throw light on the birth of biological information which, as Abel argues, requires a combination of order and complexity. This scenario gains strength from observations of scale-free framboidal forms of the greigite mineral, with a magnetic basis of assembly. And greigite's metabolic potential plays a key role in the mound scenario of Russell and coworkers-an expansion of which is suggested for including magnetism.Comment: 42 pages, 5 figures, to be published in A.R. Memorial volume, Ed Krishnaswami Alladi, Springer 201

Evolution of Primate Vocal Repertoires: Vocalization Systems as Embodied Capital for Mediating Within-group Conflict

Phylogenetic studies of communication help us understand evolutionary changes that led to human language – a form of primate communication, extraordinarily complex in terms of its varied vocalizations. Here we describe the macro-evolutionary role of life history traits on primate vocalization systems, informing our understanding of the relationships between social complexity and primate vocal repertoire size. We reviewed the primatological literature and collected information on the vocal repertoire size, social conflict, group size, endocranial volume, and maximum longevity of 42 non-human primate species. We conducted a set of analyses to examine the role of these factors on the macroevolution of vocal repertoire size over the course of primate evolution. Overall, the results strongly suggest that the embodied capital needed to support larger vocal repertoires has been selected for among anthropoid primates, especially hominoids. Large vocal repertoires help species cope with challenges of within-group conflict and cooperation that increase where larger groups have evolved with longer lifespans. While monkeys and apes developed substantially greater vocal complexity during the Late Miocene and the Early Pliocene, human language likely did not emerge until quite late in the primate evolutionary timeline, subsequent to the evolution of early hominins

Computing the minimum perimeter triangle enclosing a convex polygon: Theory and implementation.

Geometric optimization, an important field of computational geometry, finds the best possible solution to a computational problem that involves geometric objects. An attractive fundamental problem in this area is one of approximating a convex n-gon with a simpler convex k-gon, where k \u3c n, and the area or the perimeter of the approximate object is minimized. This problem arises in a wide range of applications, such as geographic information systems (GIS), spatial databases, pattern recognition, and computer graphics, to name but a few. The approximation of convex polygons with their respective enclosing triangles is a particularly interesting problem; however, finding an optimal linear time solution for computing the minimum perimeter triangle enclosing a convex polygon was a long-standing open problem, which turned out to be more difficult than determining an enclosing triangle of minimal area. In this thesis, we suggest some theoretical and practical justifications for the linear time complexity of a recently proposed optimal solution and provide an efficient and robust implementation of that solution. (Abstract shortened by UMI.) Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2003 .M43. Source: Masters Abstracts International, Volume: 42-02, page: 0618. Adviser: Asish Mukhopadhyay. Thesis (M.Sc.)--University of Windsor (Canada), 2003

Investigating the Role of Mechanical Properties in Biological Systems

There is considerable interest in measuring, with nanoscale spatial resolution, the physical and material properties of biological membranes and whole cells because of their role in the physiology of living systems. The atomic force microscope (AFM) has proven to be particularly well-suited for biological studies because samples can be maintained in near physiological conditions to preserve sample integrity (such as in a buffer solution at a physiologically relevant pH or temperature), and the imaging process is relatively nondestructive. In this work, the mechanical properties of supported lipid bilayers and neurons were examined using AFM-based techniques. Specifically, tapping mode AFM-based techniques were used to investigate the influence of lipid composition and temperature fluctuations on the physicomechanical properties of supported lipid bilayers. Topographic images were produced by tapping mode AFM, while additional compositional contrast and mechanical information was gained from phase contrast imaging, higher harmonic imaging, and scanning probe acceleration microscopy (SPAM). Importantly, all of this data was acquired simultaneously during the tapping mode AFM imaging process and the same imaging parameters were used for each experiment so that fair mechanical comparisons could be made across experiments. Lastly, force-distance curves and force volume imaging were used to better understand the effect of microtubule disruption or stabilization on the toxic ability of amyloid-beta1-42 aggregates, which are implicated in the development of Alzheimer\u27s disease. Overall, the work presented in this dissertation improved techniques for studies in mechanobiology and examined how biologically relevant factors affect the mechanical properties of lipid membranes or whole cells

Measuring information-transfer delays

In complex networks such as gene networks, traffic systems or brain circuits it is important to understand how long it takes for the different parts of the network to effectively influence one another. In the brain, for example, axonal delays between brain areas can amount to several tens of milliseconds, adding an intrinsic component to any timing-based processing of information. Inferring neural interaction delays is thus needed to interpret the information transfer revealed by any analysis of directed interactions across brain structures. However, a robust estimation of interaction delays from neural activity faces several challenges if modeling assumptions on interaction mechanisms are wrong or cannot be made. Here, we propose a robust estimator for neuronal interaction delays rooted in an information-theoretic framework, which allows a model-free exploration of interactions. In particular, we extend transfer entropy to account for delayed source-target interactions, while crucially retaining the conditioning on the embedded target state at the immediately previous time step. We prove that this particular extension is indeed guaranteed to identify interaction delays between two coupled systems and is the only relevant option in keeping with Wiener’s principle of causality. We demonstrate the performance of our approach in detecting interaction delays on finite data by numerical simulations of stochastic and deterministic processes, as well as on local field potential recordings. We also show the ability of the extended transfer entropy to detect the presence of multiple delays, as well as feedback loops. While evaluated on neuroscience data, we expect the estimator to be useful in other fields dealing with network dynamics

The volume of Gaussian states by information geometry

We formulate the problem of determining the volume of the set of Gaussian physical states in the framework of information geometry. That is, by considering phase space probability distributions parametrized by the covariances and supplying this resulting statistical manifold with the Fisher-Rao metric. We then evaluate the volume of classical, quantum and quantum entangled states for two-mode systems showing chains of strict inclusion