2,015 research outputs found

    Measurements or Static Analysis or Both?

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    To date, measurement-based WCET analysis and static analysis have largely been seen as being at odds with each other. We argue that instead they should be considered complementary, and that the combination of both represents a promising approach that provides benefits over either individual approach. In this paper we discuss in some detail how we aim to improve on our probabilistic measurement-based technique by adding static cache analysis. Specifically we are planning to make use of recent advances within the functional languages research community. The objective of this paper is not to present finished or almost finished work. Instead we hope to trigger discussion and solicit feedback from the community in order to avoid pitfalls experienced by others and to help focus our research

    Ancient DNA reveals the timing and persistence of organellar genetic bottlenecks over 3,000 years of sunflower domestication and improvement

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    Here, we report a comprehensive paleogenomic study of archaeological and ethnographic sunflower remains that provides significant new insights into the process of domestication of this important crop. DNA from both ancient and historic contexts yielded high proportions of endogenous DNA, and although archaeological DNA was found to be highly degraded, it still provided sufficient coverage to analyze genetic changes over time. Shotgun sequencing data from specimens from the Eden's Bluff archaeological site in Arkansas yielded organellar DNA sequence from specimens up to 3,100 years old. Their sequences match those of modern cultivated sunflowers and are consistent with an early domestication bottleneck in this species. Our findings also suggest that recent breeding of sunflowers has led to a loss of genetic diversity that was present only a century ago in Native American landraces. These breeding episodes also left a profound signature on the mitochondrial and plastid haplotypes in cultivars, as two types were intentionally introduced from other Helianthus species for crop improvement. These findings gained from ancient and historic sunflower specimens underscore how future in-depth gene-based analyses can advance our understanding of the pace and targets of selection during the domestication of sunflower and other crop species

    Recognizing Treelike k-Dissimilarities

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    A k-dissimilarity D on a finite set X, |X| >= k, is a map from the set of size k subsets of X to the real numbers. Such maps naturally arise from edge-weighted trees T with leaf-set X: Given a subset Y of X of size k, D(Y) is defined to be the total length of the smallest subtree of T with leaf-set Y . In case k = 2, it is well-known that 2-dissimilarities arising in this way can be characterized by the so-called "4-point condition". However, in case k > 2 Pachter and Speyer recently posed the following question: Given an arbitrary k-dissimilarity, how do we test whether this map comes from a tree? In this paper, we provide an answer to this question, showing that for k >= 3 a k-dissimilarity on a set X arises from a tree if and only if its restriction to every 2k-element subset of X arises from some tree, and that 2k is the least possible subset size to ensure that this is the case. As a corollary, we show that there exists a polynomial-time algorithm to determine when a k-dissimilarity arises from a tree. We also give a 6-point condition for determining when a 3-dissimilarity arises from a tree, that is similar to the aforementioned 4-point condition.Comment: 18 pages, 4 figure

    γδ T cells affect IL-4 production and B-cell tolerance

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    γδ T cells can influence specific antibody responses. Here, we report that mice deficient in individual γδ T-cell subsets have altered levels of serum antibodies, including all major subclasses, sometimes regardless of the presence of αβ T cells. One strain with a partial γδ deficiency that increases IgE antibodies also displayed increases in IL-4–producing T cells (both residual γδ T cells and αβ T cells) and in systemic IL-4 levels. Its B cells expressed IL-4–regulated inhibitory receptors (CD5, CD22, and CD32) at diminished levels, whereas IL-4–inducible IL-4 receptor α and MHCII were increased. They also showed signs of activation and spontaneously formed germinal centers. These mice displayed IgE-dependent features found in hyper-IgE syndrome and developed antichromatin, antinuclear, and anticytoplasmic autoantibodies. In contrast, mice deficient in all γδ T cells had nearly unchanged Ig levels and did not develop autoantibodies. Removing IL-4 abrogated the increases in IgE, antichromatin antibodies, and autoantibodies in the partially γδ-deficient mice. Our data suggest that γδ T cells, controlled by their own cross-talk, affect IL-4 production, B-cell activation, and B-cell tolerance

    A robust prognostic signature for hormone-positive node-negative breast cancer

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    BACKGROUND: Systemic chemotherapy in the adjuvant setting can cure breast cancer in some patients that would otherwise recur with incurable, metastatic disease. However, since only a fraction of patients would have recurrence after surgery alone, the challenge is to stratify high-risk patients (who stand to benefit from systemic chemotherapy) from low-risk patients (who can safely be spared treatment related toxicities and costs). METHODS: We focus here on risk stratification in node-negative, ER-positive, HER2-negative breast cancer. We use a large database of publicly available microarray datasets to build a random forests classifier and develop a robust multi-gene mRNA transcription-based predictor of relapse free survival at 10 years, which we call the Random Forests Relapse Score (RFRS). Performance was assessed by internal cross-validation, multiple independent data sets, and comparison to existing algorithms using receiver-operating characteristic and Kaplan-Meier survival analysis. Internal redundancy of features was determined using k-means clustering to define optimal signatures with smaller numbers of primary genes, each with multiple alternates. RESULTS: Internal OOB cross-validation for the initial (full-gene-set) model on training data reported an ROC AUC of 0.704, which was comparable to or better than those reported previously or obtained by applying existing methods to our dataset. Three risk groups with probability cutoffs for low, intermediate, and high-risk were defined. Survival analysis determined a highly significant difference in relapse rate between these risk groups. Validation of the models against independent test datasets showed highly similar results. Smaller 17-gene and 8-gene optimized models were also developed with minimal reduction in performance. Furthermore, the signature was shown to be almost equally effective on both hormone-treated and untreated patients. CONCLUSIONS: RFRS allows flexibility in both the number and identity of genes utilized from thousands to as few as 17 or eight genes, each with multiple alternatives. The RFRS reports a probability score strongly correlated with risk of relapse. This score could therefore be used to assign systemic chemotherapy specifically to those high-risk patients most likely to benefit from further treatment

    New SPB stars in the field of the young open cluster NGC 2244 discovered by the MOST photometric satellite

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    During two weeks of nearly continuous optical photometry of the young open cluster NGC 2244 obtained by the MOST satellite, we discovered two new SPB stars, GSC 00154-00785 and GSC 00154-01871. We present frequency analyses of the MOST light curves of these stars, which reveal two oscillation frequencies (0.61 and 0.71 c/d) in GSC 00154-00785 and two (0.40 and 0.51 c/d) in GSC 00154-01871. These frequency ranges are consistent with g-modes of 2\ell \leq 2 excited in models of main-sequence or pre-main-sequence (PMS) stars of masses 4.5 - 5 MM_{\odot} and solar composition (X,Z)=(0.7,0.02)(X, Z)= (0.7, 0.02). Published proper motion measurements and radial velocities are insufficient to establish unambiguously cluster membership for these two stars. However, the PMS models which fit best their eigenspectra have ages consistent with NGC 2244. If cluster membership can be confirmed, these would be the first known PMS SPB stars, and would open a new window on testing asteroseismically the interior structures of PMS stars.Comment: accepted for publication in MNRA

    Stuck in the slow lane: reconceptualising the links between gender, transport and social exclusion

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    This article draws upon primary research undertaken with over 3,000 women in the North East of England to explore the links between women, transport and the labour market. The research, funded by the ESF, advances the idea of spatiality as a social construction and builds on seminal studies relating to women and poverty to consider the way in which a gender division of transport constrains women's mobility and restricts their employment opportunities. It is likely to contribute to important debates, concerning strategies to tackle worklessness and the most effective spatial level at which to configure public transport networks

    An Exploration of Financial Management Programming for Residents in One Homeless Shelter: A Qualitative Institutional Case Study

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    Introduction: Homelessness affects the economy, societies, and individuals’ physical, mental, and emotional well-being. Occupational therapy is a holistic profession that works with all populations across the lifespan. Financial management is a life skill that many Americans struggle with. Evidence on financial management skill development within homeless shelters and occupational therapy is sparse. Occupational justice is a theoretical framework that supports the right for residents in a homeless shelter to have direct interventions toward skill development, such as education in financial management. Methods: This institutional case study explored a homeless shelter to gain knowledge of real-life program phenomena, with focus on financial management. The primary location for this study was an emergency homeless shelter in the midwestern United States. Five employee participants were recruited through purposeful selection. Results: Participants felt that financial management was an effective intervention for residents in a homeless shelter, although success related to an overall comprehensive program. Conclusion: This study proposes financial management as an important intervention area for homeless shelters and OT practice and suggests the OT profession is qualified to fill roles in a homeless shelter setting
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