Social Knowledge and Signals in Primates

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98165/1/ajp22103.pd

Adventures in Invariant Theory

We provide an introduction to enumerating and constructing invariants of group representations via character methods. The problem is contextualised via two case studies arising from our recent work: entanglement measures, for characterising the structure of state spaces for composite quantum systems; and Markov invariants, a robust alternative to parameter-estimation intensive methods of statistical inference in molecular phylogenetics.Comment: 12 pp, includes supplementary discussion of example

Representing Partitions on Trees

In evolutionary biology, biologists often face the problem of constructing a phylogenetic tree on a set X of species from a multiset Π of partitions corresponding to various attributes of these species. One approach that is used to solve this problem is to try instead to associate a tree (or even a network) to the multiset ΣΠ consisting of all those bipartitions {A,X − A} with A a part of some partition in Π. The rational behind this approach is that a phylogenetic tree with leaf set X can be uniquely represented by the set of bipartitions of X induced by its edges. Motivated by these considerations, given a multiset Σ of bipartitions corresponding to a phylogenetic tree on X, in this paper we introduce and study the set P(Σ) consisting of those multisets of partitions Π of X with ΣΠ = Σ. More specifically, we characterize when P(Σ) is non-empty, and also identify some partitions in P(Σ) that are of maximum and minimum size. We also show that it is NP-complete to decide when P(Σ) is non-empty in case Σ is an arbitrary multiset of bipartitions of X. Ultimately, we hope that by gaining a better understanding of the mapping that takes an arbitrary partition system Π to the multiset ΣΠ, we will obtain new insights into the use of median networks and, more generally, split-networks to visualize sets of partitions

Quartet compatibility and the quartet graph

A collection P of leaf-labelled trees is compatible if there exists a single leaf-labelled tree that displays each of the trees in P. Despite its difficulty, determining the compatibility of P is a fundamental task in evolutionary biology. Attractive characterizations in terms of chordal graphs have been previously given for this problem as well as for the problems of (i) determining if there is a unique tree that displays each of the trees in P, that is 'P is definitive and (ii) determining if there is a tree that displays P and has the property that every other tree that displays P is a refinement of it, that is 'P identifies a leaf-labelled tree. In this paper, we describe new characterizations of each of these problems in terms of edge colourings. Furthermore, for an arbitrary leaf-labelled tree 'T, we also determine the minimum number of 'quartets' required to identify 'T, thus correcting a previously published result

The susceptibility of baboons to the novel immunosuppressant, FTY720

Bibliography: leaves 109-118.Since there is a major scarcity of donor organs world-wide, the experimental search for human organs has focused on two alternatives; mechanical devices and cross-species transplants. The use of mechanical devices as substitute organs is understandably limited due to complications from trying to duplicate the function of complex organs such as the liver. This has resulted in a renewed interest in xenotransplantation. Organs from non-human primates would arguably be the organs of choice but ethical consideration prevents this. The transplantation of organs from pigs or sheep to humans i.e. xenotransplants, results in hyperacute rejection. The development of immunosuppressive agents such as Cyc1osporine A and Tacrolimus have significantly improved the survival of organ transplants. However, although there is a good 1-5 year survival, the recurrent problem of chronic rejection still remains, and unresponsiveness to allografts has never been induced by these immunosuppressive agents. More importantly, the presence of adverse side effects including immunological complications and drug toxicity e.g. nephrotoxicity, remains a serious problem. Since the drugs currently available for allotransplantation preferably target T -cells, and are therefore unlikely to be sufficient for xenotransplantation where there is a strong B-cell driven response, there is a need for new immunosuppressive agents. FTY720 (2 amino-2-(2-[ 4-octylphenyl] ethyl)-1,3-propanediol hydrochloride), a novel, immunosuppressive drug active in rodent and dog transplantation models, has shown no toxic side effects in pre-clinical studies although no long-term patient studies exist

Use of low-cost particle counters for cotton dust exposure assessment in textile mills in low- and middle-income countries

OBJECTIVE: There is a lack of consensus on methods for cotton dust measurement in the textile industry, and techniques vary between countries-relying mostly on cumbersome, traditional approaches. We undertook comparisons of standard, gravimetric methods with low-cost optical particle counters for personal and area dust measurements in textile mills in Pakistan. METHODS: We included male textile workers from the weaving sections of seven cotton mills in Karachi. We used the Institute of Occupational Medicine (IOM) sampler with a Casella Apex 2 standard pump and the Purple Air (PA-II-SD) for measuring personal exposures to inhalable airborne particles (n = 31). We used the Dylos DC1700 particle counter, in addition to the two above, for area-level measurements (n = 29). RESULTS: There were no significant correlations between the IOM and PA for personal dust measurements using the original (r = -0.15, P = 0.4) or log-transformed data (r = -0.32, P = 0.07). Similarly, there were no significant correlations when comparing the IOM with either of the particle counters (PA and Dylos) for area dust measurements, using the original (r = -0.07, P = 0.7; r = 0.10, P = 0.6) or log-transformed data (r = -0.09, P = 0.6; r = 0.07, P = 0.7). CONCLUSION: Our findings show a lack of correlation between the gravimetric method and the use of particle counters in both personal and area measurements of cotton dust, precluding their use for measuring occupational exposures to airborne dust in textile mills. There continues to be a need to develop low-cost instruments to help textile industries in low- and middle-income countries to perform cotton dust exposure assessment

The effect of exposure to biomass smoke on respiratory symptoms in adult rural and urban Nepalese populations

Peer reviewedPublisher PD

Neighborhoods of trees in circular orderings

In phylogenetics, a common strategy used to construct an evolutionary tree for a set of species X is to search in the space of all such trees for one that optimizes some given score function (such as the minimum evolution, parsimony or likelihood score). As this can be computationally intensive, it was recently proposed to restrict such searches to the set of all those trees that are compatible with some circular ordering of the set X. To inform the design of efficient algorithms to perform such searches, it is therefore of interest to find bounds for the number of trees compatible with a fixed ordering in the neighborhood of a tree that is determined by certain tree operations commonly used to search for trees: the nearest neighbor interchange (nni), the subtree prune and regraft (spr) and the tree bisection and reconnection (tbr) operations. We show that the size of such a neighborhood of a binary tree associated with the nni operation is independent of the tree’s topology, but that this is not the case for the spr and tbr operations. We also give tight upper and lower bounds for the size of the neighborhood of a binary tree for the spr and tbr operations and characterize those trees for which these bounds are attained

Associations between smoke-free vehicle legislation and childhood admissions to hospital for asthma in Scotland : an interrupted time-series analysis of whole-population data

Peer reviewedPublisher PD

Editorial: Resource Recovery From Waste

This is the final version. Available from Frontiers Media via the DOI in this record. NERCESRCDEFR