Cohesin biology meets the loop extrusion model

Extensive research has revealed that cohesin acts as a topological device, trapping chromosomal DNA within a large tripartite ring. In so doing, cohesin contributes to the formation of compact and organized genomes. How exactly the cohesin subunits interact, how it opens, closes, and translocates on chromatin, and how it actually tethers DNA strands together are still being elucidated. A comprehensive understanding of these questions will shed light on how cohesin performs its many functions, including its recently proposed role as a chromatid loop extruder. Here, we discuss this possibility in light of our understanding of the molecular properties of cohesin complexes

Water Exchange Systems

In this chapter we present an exchange systems approach to evaluate the potential of water markets to provide sustainable and equitable access for all. The approach is sourced from marketing theory, which in turn is constructed on a social exchange and general systems theory platform (Bagozzi, 1978; Layton, 2007). The exchange systems concept offers a systemic view of exchange that allows for the integration of broader economic and social considerations into the design of water markets. We illustrate different types of exchange systems to offer the reader a broader perspective on water markets. Such a perspective can enable new thinking in how water provision systems can contribute to improved human health. We begin with a general introduction to the marketing exchange concept and subsequently trace its evolution to exchange systems

Vermicompost as a fertilizer for urban and peri-urban farms: Perceptions of farmers in Accra, Ghana

Vermicompost is considered a valuable organic fertilizer in many tropical regions, but has rarely been used in sub-Saharan Africa. A study in Accra, Ghana, assessed urban and peri-urban (UP) farmers’ fertilizer and pesticide use, knowledge of earthworms, fertilizer performance criteria, and attitudes toward vermicompost as a fertilizer. Twenty-six farmers involved in irrigated vegetable farming and three subsistence farmers were interviewed. Farmers were aware that earthworm activity was associated with soil fertility, and some associated insecticide applications to reduced earthworm populations. Farmers used the greenness of leaves, crop emergence, stand and yield as indicators of fertilizer performance. Farmers resisted making statements about vermicompost before testing it, and advised that its fertilizer value be tested during the dry season. Farmers involved in irrigated vegetable farming had insufficient space and time for on-farm vermicomposting, while subsistence farmers lacked a reliable access to water necessary for on-farm vermicomposting; but both types of farmers were interested in adopting vermicompost if it improved crop performance. Such lack of farm resources suggest that a commercial facility would be best suited to produce vermicompost from organic waste, which would then be sold to farmers

Use of positron emission tomography in evaluation of brachial plexopathy in breast cancer patients

18-Fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) has previously been used successfully to image primary and metastatic breast cancer. In this pilot study, 19 breast cancer patients with symptoms/signs referrable to the brachial plexus were evaluated with 18FDG-PET. In 11 cases computerized tomography (CT) scanning was also performed. Of the 19 patients referred for PET study, 14 had abnormal uptake of 18FDG in the region of the symptomatic plexus. Four patients had normal PET studies and one had increased FDG uptake in the chest wall that accounted for her axillary pain. CT scans were performed in 9 of the 14 patients who had positive brachial plexus PET studies; six of these were either normal or showed no clear evidence of recurrent disease, while three CTs demonstrated clear brachial plexus involvement. Of two of the four patients with normal PET studies, one has had complete resolution of symptoms untreated while the other was found to have cervical disc herniation on magnetic resonance imaging (MRI) scan. The remaining two patients almost certainly had radiation-induced plexopathy and had normal CT, MRI and PET study. These data suggest that 18FDG-PET scanning is a useful tool in evaluation of patients with suspected metastatic plexopathy, particularly if other imaging studies are normal. It may also be useful in distinguishing between radiation-induced and metastatic plexopathy. © 1999 Cancer Research Campaig

Some lessons learned from engaging in WaSH participatory action research in Melanesian informal settlements

In Melanesian countries there has been a large flux of people from rural to urban and peri-urban areas, resulting an in increased number living in informal settlements. These settlements often lack connections to mains water and sewerage lines and formal solid waste collection. Our project used a participatory action research (PAR) approach to work in partnership with informal settlement communities and enabling actors to achieve the self-determined WaSH conditions which participants felt would improve the well-being of those living in informal settlements. Because the PAR approach encourages reflection and adaptation, we learned lessons that were incorporated into the design of ongoing and future processes, and this paper presents five such lessons which we judge to be of practical use for WaSH enabling actors

Opportunities and Challenges for the development of 'Core Outcome Sets' in Neuro-Oncology

Core Outcome Sets (COS) define minimum outcomes to be measured and reported in clinical effectiveness trials for a particular health condition/health area. Despite recognition as critical to clinical research design for other health areas, none have been developed for neuro-oncology. COS development projects should carefully consider: scope (how the COS should be used), stakeholders involved in development (including patients as both research partners and participants), and consensus methodologies used (typically a Delphi survey and consensus meeting), as well as dissemination plans. Developing COS for neuro-oncology is potentially challenging due to extensive tumor subclassification (including molecular stratification), different symptoms related to anatomical tumor location, and variation in treatment options. Development of a COS specific to tumor subtype, in a specific location, for a particular intervention may be too narrow and would be unlikely to be used. Equally, a COS that is applicable across a wider area of neuro-oncology may be too broad and therefore lack specificity. This review describes why and how a COS may be developed, and discusses challenges for their development, specific to neuro-oncology. The COS under development are briefly described, including: adult glioma, incidental/untreated meningioma, meningioma requiring intervention, and adverse events from surgical intervention for pediatric brain tumors. Keywords: clinical trial; core outcome set; effectiveness; glioma; meningioma

Interpretations of Presburger Arithmetic in Itself

Presburger arithmetic PrA is the true theory of natural numbers with addition. We study interpretations of PrA in itself. We prove that all one-dimensional self-interpretations are definably isomorphic to the identity self-interpretation. In order to prove the results we show that all linear orders that are interpretable in (N,+) are scattered orders with the finite Hausdorff rank and that the ranks are bounded in terms of the dimension of the respective interpretations. From our result about self-interpretations of PrA it follows that PrA isn't one-dimensionally interpretable in any of its finite subtheories. We note that the latter was conjectured by A. Visser.Comment: Published in proceedings of LFCS 201

Care Transitions in Childhood Cancer Survivorship: Providers' Perspectives

Purpose: Most adolescent and young adult (AYA)-aged childhood cancer survivors develop physical and/or psychosocial sequelae; however, many do not receive long-term follow-up (LTF) critical for screening, prevention, and treatment of late effects. To develop a health services research agenda to optimize care models, we conducted qualitative research with LTF providers examining existing models, and successes and challenges in maintaining survivors' connections to care across their transition to adulthood

Descriptive Complexity of Deterministic Polylogarithmic Time and Space

We propose logical characterizations of problems solvable in deterministic polylogarithmic time (PolylogTime) and polylogarithmic space (PolylogSpace). We introduce a novel two-sorted logic that separates the elements of the input domain from the bit positions needed to address these elements. We prove that the inflationary and partial fixed point vartiants of this logic capture PolylogTime and PolylogSpace, respectively. In the course of proving that our logic indeed captures PolylogTime on finite ordered structures, we introduce a variant of random-access Turing machines that can access the relations and functions of a structure directly. We investigate whether an explicit predicate for the ordering of the domain is needed in our PolylogTime logic. Finally, we present the open problem of finding an exact characterization of order-invariant queries in PolylogTime.Comment: Submitted to the Journal of Computer and System Science