872 research outputs found

    Visual estimation of ACL injury risk: Efficient assessment method, group differences, and expertise mechanisms

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    Simple observational assessment of movement quality (e.g., drop vertical jump biomechanics) is an efficient and low cost method for anterior cruciate ligament (ACL) injury screening and prevention. A recently developed test (see www.ACL-IQ.org) has revealed substantial cross-professional/group differences in visual ACL injury risk estimation skill. Specifically, parents, sport coaches, and to some degree sports medicine physicians, would likely benefit from training or the use of decision support tools. In addition, expertise mechanisms (perceptual-cognitive characteristics of skilled performers) were investigated in order to design training systems to improve risk estimation performance

    Linking phytoplankton community metabolism to the individual size distribution

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    This is the final version of the article. Available from the publisher via the DOI in this recordQuantifying variation in ecosystem metabolism is critical to predicting the impacts of environmental change on the carbon cycle. We used a metabolic scaling framework to investigate how body size and temperature influence phytoplankton community metabolism. We tested this framework using phytoplankton sampled from an outdoor mesocosm experiment, where communities had been either experimentally warmed (+ 4 °C) for 10 years or left at ambient temperature. Warmed and ambient phytoplankton communities differed substantially in their taxonomic composition and size structure. Despite this, the response of primary production and community respiration to long- and short-term warming could be estimated using a model that accounted for the size- and temperature dependence of individual metabolism, and the community abundance-body size distribution. This work demonstrates that the key metabolic fluxes that determine the carbon balance of planktonic ecosystems can be approximated using metabolic scaling theory, with knowledge of the individual size distribution and environmental temperature.NERC. Grant Number: PASW06

    Impact of boundaries on fully connected random geometric networks

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    Many complex networks exhibit a percolation transition involving a macroscopic connected component, with universal features largely independent of the microscopic model and the macroscopic domain geometry. In contrast, we show that the transition to full connectivity is strongly influenced by details of the boundary, but observe an alternative form of universality. Our approach correctly distinguishes connectivity properties of networks in domains with equal bulk contributions. It also facilitates system design to promote or avoid full connectivity for diverse geometries in arbitrary dimension.Comment: 6 pages, 3 figure

    Environmental fluctuations accelerate molecular evolution of thermal tolerance in a marine diatom

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    This is the final version of the article. Available from Springer Nature via the DOI in this recordThe publisher correction to this article is in ORE at: http://hdl.handle.net/10871/34487Diatoms contribute roughly 20% of global primary production, but the factors determining their ability to adapt to global warming are unknown. Here we quantify the capacity for adaptation to warming in the marine diatom Thalassiosira pseudonana. We find that evolutionary rescue under severe (32 °C) warming is slow, but adaptation to more realistic scenarios where temperature increases are moderate (26 °C) or fluctuate between benign and severe conditions is rapid and linked to phenotypic changes in metabolic traits and elemental composition. Whole-genome re-sequencing identifies genetic divergence among populations selected in the different warming regimes and between the evolved and ancestral lineages. Consistent with the phenotypic changes, the most rapidly evolving genes are associated with transcriptional regulation, cellular responses to oxidative stress and redox homeostasis. These results demonstrate that the evolution of thermal tolerance in marine diatoms can be rapid, particularly in fluctuating environments, and is underpinned by major genomic and phenotypic change.This study was funded by a Leverhulme Trust research grant (RPG-2013-335). Whole genome re-sequencing was carried out at Exeter Sequencing Service and Computational core facilities at the University of Exeter, where Dr. Karen Moore, Dr. Audrey Farbos, Paul O’Neill, and Dr. Konrad Paszkiewicz lead the handling of the samples. Exeter Squencing Services are supported by Medical Research Council Clinical Infrastructure award (MR/M008924/1), Wellcome Trust Institutional Strategic Support Fund (WT097835MF), Wellcome Trust Multi User Equipment Award (WT101650MA), and BBSRC LOLA award (BB/K003240/1)

    The Complexity of Drawing Graphs on Few Lines and Few Planes

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    It is well known that any graph admits a crossing-free straight-line drawing in R3\mathbb{R}^3 and that any planar graph admits the same even in R2\mathbb{R}^2. For a graph GG and d{2,3}d \in \{2,3\}, let ρd1(G)\rho^1_d(G) denote the minimum number of lines in Rd\mathbb{R}^d that together can cover all edges of a drawing of GG. For d=2d=2, GG must be planar. We investigate the complexity of computing these parameters and obtain the following hardness and algorithmic results. - For d{2,3}d\in\{2,3\}, we prove that deciding whether ρd1(G)k\rho^1_d(G)\le k for a given graph GG and integer kk is R{\exists\mathbb{R}}-complete. - Since NPR\mathrm{NP}\subseteq{\exists\mathbb{R}}, deciding ρd1(G)k\rho^1_d(G)\le k is NP-hard for d{2,3}d\in\{2,3\}. On the positive side, we show that the problem is fixed-parameter tractable with respect to kk. - Since RPSPACE{\exists\mathbb{R}}\subseteq\mathrm{PSPACE}, both ρ21(G)\rho^1_2(G) and ρ31(G)\rho^1_3(G) are computable in polynomial space. On the negative side, we show that drawings that are optimal with respect to ρ21\rho^1_2 or ρ31\rho^1_3 sometimes require irrational coordinates. - Let ρ32(G)\rho^2_3(G) be the minimum number of planes in R3\mathbb{R}^3 needed to cover a straight-line drawing of a graph GG. We prove that deciding whether ρ32(G)k\rho^2_3(G)\le k is NP-hard for any fixed k2k \ge 2. Hence, the problem is not fixed-parameter tractable with respect to kk unless P=NP\mathrm{P}=\mathrm{NP}

    Saccharomyces cerevisiae Rad9 Acts as a Mec1 Adaptor to Allow Rad53 Activation

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    SummaryBackground: The DNA damage checkpoint is a protein kinase-based signaling system that detects and signals physical alterations in DNA. Despite having identified many components of this signaling cascade, the exact mechanisms by which checkpoint kinases are activated after DNA damage, as well as the role of the checkpoint mediators, remain poorly understood.Results: To elucidate the mechanisms that underlie the MEC1 and RAD9-dependent activation of Rad53, the Saccharomyces cerevisiae ortholog of Chk2, we mapped and characterized in vivo phosphorylation sites present on Rad53 after DNA damage by mass spectrometry. We find that Rad53 requires for its activation multisite phosphorylation on a number of typical and atypical Mec1 phosphorylation sites, thus confirming that Rad53 is a direct target of Mec1, the mammalian ATR homolog. Moreover, by using biochemical reconstitution experiments, we demonstrate that efficient and direct phosphorylation of Rad53 by Mec1 is only observed in the presence of purified Rad9, the archetypal checkpoint mediator. We find that the stimulatory activity of Rad9 requires a phospho- and FHA-dependent interaction with Rad53, which allows Rad53 to be recognized as a substrate for Mec1.Conclusions: Our results indicate that Rad9 acts as a bona fide signaling adaptor that enables Rad53 phosphorylation by Mec1. Given the high degree of conservation of checkpoint signaling in eukaryotes, we propose that one of the critical functions of checkpoint mediators such as MDC1, 53BP1, or Brca1 is to act as PIKK adaptors during the DNA damage response

    Drawing Planar Graphs with Few Geometric Primitives

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    We define the \emph{visual complexity} of a plane graph drawing to be the number of basic geometric objects needed to represent all its edges. In particular, one object may represent multiple edges (e.g., one needs only one line segment to draw a path with an arbitrary number of edges). Let nn denote the number of vertices of a graph. We show that trees can be drawn with 3n/43n/4 straight-line segments on a polynomial grid, and with n/2n/2 straight-line segments on a quasi-polynomial grid. Further, we present an algorithm for drawing planar 3-trees with (8n17)/3(8n-17)/3 segments on an O(n)×O(n2)O(n)\times O(n^2) grid. This algorithm can also be used with a small modification to draw maximal outerplanar graphs with 3n/23n/2 edges on an O(n)×O(n2)O(n)\times O(n^2) grid. We also study the problem of drawing maximal planar graphs with circular arcs and provide an algorithm to draw such graphs using only (5n11)/3(5n - 11)/3 arcs. This is significantly smaller than the lower bound of 2n2n for line segments for a nontrivial graph class.Comment: Appeared at Proc. 43rd International Workshop on Graph-Theoretic Concepts in Computer Science (WG 2017

    Computer integrated NDE

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    Early investigations of Sulzer-Innotec in 1990 showed that, compared to other NDT methods such as radiography and thermography, ultrasonic inspection is very effective for the detection of internal flaws in engineered materials such as fiber-reinforced composite materials. In the inspection of such parts by ultrasonic immersion scanning, preparation and set-up time can be a problem especially for complex parts. This presentation describes a cooperative project between Sulzer-Innotec and Tektrend to design and implement a PC-controlled and CAD-supported ultrasonic scanning and data acquisition system. The system also includes artificial intelligence for automated data interpretation and extensive imaging capabilities. The system is described and applications demonstrating the capabilities are presented

    Achieving community-based postpartum follow up in eastern Uganda: the field experience from the MamaMiso Study on antenatal distribution of misoprostol.

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    BackgroundAdvance provision of misoprostol to women during antenatal care aims to achieve broader access to uterotonics for the prevention of postpartum hemorrhage. Studies of this community-based approach usually involve antenatal education as well as timely postpartum follow-up visits to confirm maternal and neonatal outcomes. The MamaMiso study in Mbale, Uganda sought to assess the feasibility of conducting follow-up visits in the postpartum period following advance provision of misoprostol for postpartum hemorrhage prevention. MamaMiso recruited women during antenatal care visits. Participants were asked to contact the research team within 48 h of giving birth so that postpartum follow-up visits could be carried out at their homes. Women's baseline and delivery characteristics were collected and analyzed with respect to follow-up time ('on time' ≤ 7 days, 'late' > 7 days, and 'lost to follow up'). Every woman who was followed up late due to a failure to report the delivery was asked for the underlying reasons for the delay. When attempts at following up participants were unsuccessful, a file note was generated explaining the details of the failure. We abstracted data and identified themes from these notes.ResultsOf 748 recruited women, 700 (94%) were successfully followed up during the study period, 465 (62%) within the first week postpartum. The median time to follow up was 4 days and was similar for women who delivered at home or in facilities and for women who had attended or unattended births. Women recruited at the urban hospital site (as opposed to rural health clinics) were more likely to be lost to follow up or followed up late. Of the women followed up late, 202 provided a reason. File notes explaining failed attempts at follow up were generated for 164 participants. Several themes emerged from qualitative analysis of these notes including phone difficulties, inaccurate baseline information, misperceptions, postpartum travel, and the condition of the mother and neonate.ConclusionsKeeping women connected to the health system in the postpartum period is feasible, though reaching them within the first week of their delivery is challenging. Understanding characteristics of women who are harder to reach can help tailor follow-up efforts and elucidate possible biases in postpartum study data. Trial Registration Number ISRCTN70408620 December 28, 2011
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