Affine configurations and pure braids

We show that the fundamental group of the space of ordered affine-equivalent configurations of at least five points in the real plane is isomorphic to the pure braid group modulo its centre. In the case of four points this fundamental group is free with eleven generators.Comment: 5 pages, 1 figure, final version; to appear in Discrete & Computational Geometry, available from the publishers at http://www.springerlink.com/content/384516n7q24811ph

Semiautomated text analytics for qualitative data synthesis

Approaches to synthesizing qualitative data have, to date, largely focused on integrating the findings from published reports. However, developments in text mining software offer the potential for efficient analysis of large pooled primary qualitative datasets. This case study aimed to (a) provide a step‐by‐step guide to using one software application, Leximancer, and (b) interrogate opportunities and limitations of the software for qualitative data synthesis. We applied Leximancer v4.5 to a pool of five qualitative, UK‐based studies on transportation such as walking, cycling, and driving, and displayed the findings of the automated content analysis as intertopic distance maps. Leximancer enabled us to “zoom out” to familiarize ourselves with, and gain a broad perspective of, the pooled data. It indicated which studies clustered around dominant topics such as “people.” The software also enabled us to “zoom in” to narrow the perspective to specific subgroups and lines of enquiry. For example, “people” featured in men's and women's narratives but were talked about differently, with men mentioning “kids” and “old,” whereas women mentioned “things” and “stuff.” The approach provided us with a fresh lens for the initial inductive step in the analysis process and could guide further exploration. The limitations of using Leximancer were the substantial data preparation time involved and the contextual knowledge required from the researcher to turn lines of inquiry into meaningful insights. In summary, Leximancer is a useful tool for contributing to qualitative data synthesis, facilitating comprehensive and transparent data coding but can only inform, not replace, researcher‐led interpretive work

A novel cellular pathway of antigen presentation and CD4 T cell activation in vivo

Dendritic cell activation of CD4 T cells in the lymph node draining a site of infection or vaccination is widely considered the central event in initiating adaptive immunity. The accepted dogma is that this occurs by stimulating local activation and antigen acquisition by dendritic cells, with subsequent lymph node migration, however the generalizability of this mechanism is unclear. Here we show that in some circumstances antigen can bypass the injection site inflammatory response, draining freely and rapidly to the lymph nodes where it interacts with subcapsular sinus (SCS) macrophages resulting in their death. Debris from these dying SCS macrophages is internalized by monocytes recruited from the circulation. This coordinated response leads to antigen presentation by monocytes and interactions with naïve CD4 T cells that can drive the initiation of T cell and B cell responses. These studies demonstrate an entirely novel pathway leading to initiation of adaptive immune responses in vivo

Garside and quadratic normalisation: a survey

Starting from the seminal example of the greedy normal norm in braid monoids, we analyse the mechanism of the normal form in a Garside monoid and explain how it extends to the more general framework of Garside families. Extending the viewpoint even more, we then consider general quadratic normalisation procedures and characterise Garside normalisation among them.Comment: 30 page

Imaging interactions between the immune and cardiovascular systems in vivo by multiphoton microscopy

Several recent studies in immunology have used multiphoton laser-scanning microscopy to visualise the induction of an immune response in real time in vivo. These experiments are illuminating the cellular and molecular interactions involved in the induction, maintenance and regulation of immune responses. Similar approaches are being applied in cardiovascular research where there is an increasing body of evidence to support a significant role for the adaptive immune system in vascular disease. As such, we have begun to dissect the role of T lymphocytes in atherosclerosis in real time in vivo. Here, we provide step-by-step guides to the various stages involved in visualising the migration of T cells within a lymph node and their infiltration into inflamed tissues such as atherosclerotic arteries. These methods provide an insight into the mechanisms involved in the activation and function of immune cells in vivo

A systematic map of evidence on the contribution of forests to poverty alleviation

This is the final version. Available from the publisher via the DOI in this record.Background: Forests provide an essential resource to the livelihoods of an estimated 20% of the global population. The contribution of forest ecosystems and forest-based resources to poverty reduction is increasingly emphasized in international policy discourse and conservation and development investments. However, evidence measuring the effect of forest-based activities on poverty outcomes remains scattered and unclear. Lack of systematic understanding of forest-poverty relationships, in turn, inhibits research, policymaking, and efficient financial resource allocation. Methods: To identify relevant studies for inclusion in this systematic map we searched six bibliographic databases, 15 organizational websites, eight systematic evidence syntheses (reviews and maps), and solicited information from key informants. Search results were screened for relevance against predefined inclusion criteria at title, abstract, and full text levels, according to a published protocol. Included articles were coded using a predefined framework. Trends in the evidence, knowledge gaps and relatively well-researched sub-topics are reported in a narrative synthesis. Occurrence and extent of existing evidence about links between interventions and outcomes are presented in a visual heatmap. Data are available through the open access Evidence for Nature and People Data Portal (http://www.natureandpeopleevidence.org). Results: A total of 242 articles were included in the systematic map database. Included articles measured effects of 14 forest-based intervention types on 11 poverty dimensions. The majority of the evidence base (72%) examined links between productivity-enhancement strategies (e.g. forest management, agroforestry, and habitat management) and monetary income and/or social capital outcomes. Other areas with high occurrence of articles include linkages between interventions involving governance, individual rights/empowerment or linked enterprises/livelihood alternatives with impacts on monetary income from direct sale of goods. A key knowledge gap was on the impacts of investment-based interventions (i.e. enhancing produced, human, and social capitals). Another was the impacts of forest-based interventions on financial capital (savings, debt), non-monetary benefits, and health. Conclusions: The evidence base on forest-based productive activities and poverty alleviation is growing but displays a number of biases in the distribution of articles on key linkages. Priorities for future systematic reviews and evaluations include in-depth examinations into the impacts of rights-based activities (e.g. governance, empowerment) on poverty dimensions; and productivity-enhancing activities on social capital. More comprehensive and robust evidence is needed to better understand the synergies and trade-offs among the different objectives of forest conservation and management and variation in outcomes for different social groups in different social-ecological contexts

Abelian subgroups of Garside groups

In this paper, we show that for every abelian subgroup $H$ of a Garside group, some conjugate $g^{-1}Hg$ consists of ultra summit elements and the centralizer of $H$ is a finite index subgroup of the normalizer of $H$. Combining with the results on translation numbers in Garside groups, we obtain an easy proof of the algebraic flat torus theorem for Garside groups and solve several algorithmic problems concerning abelian subgroups of Garside groups.Comment: This article replaces our earlier preprint "Stable super summit sets in Garside groups", arXiv:math.GT/060258

Developing a xenograft model of human vasculature in the mouse ear pinna

Humanised xenograft models allow for the analysis of human tissue within a physiological environment in vivo. However, current models often rely on the angiogenesis and ingrowth of recipient vasculature to perfuse tissues, preventing analysis of biological processes and diseases involving human blood vessels. This limits the effectiveness of xenografts in replicating human physiology and may lead to issues with translating findings into human research. We have designed a xenograft model of human vasculature to address this issue. Human subcutaneous fat was cultured in vitro to promote blood vessel outgrowth prior to implantation into immunocompromised mice. We demonstrate that implants survived, retained human vasculature and anastomosed with the circulatory system of the recipient mouse. Significantly, by performing transplants into the ear pinna, this system enabled intravital observation of xenografts by multiphoton microscopy, allowing us to visualise the steps leading to vascular cytoadherence of erythrocytes infected with the human parasite Plasmodium falciparum. This model represents a useful tool for imaging the interactions that occur within human tissues in vivo and permits visualization of blood flow and cellular recruitment in a system which is amenable to intervention for various studies in basic biology together with drug evaluation and mechanism of action studies