2,578 research outputs found

    Efficient LZ78 factorization of grammar compressed text

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    We present an efficient algorithm for computing the LZ78 factorization of a text, where the text is represented as a straight line program (SLP), which is a context free grammar in the Chomsky normal form that generates a single string. Given an SLP of size nn representing a text SS of length NN, our algorithm computes the LZ78 factorization of TT in O(nN+mlog⁑N)O(n\sqrt{N}+m\log N) time and O(nN+m)O(n\sqrt{N}+m) space, where mm is the number of resulting LZ78 factors. We also show how to improve the algorithm so that the nNn\sqrt{N} term in the time and space complexities becomes either nLnL, where LL is the length of the longest LZ78 factor, or (Nβˆ’Ξ±)(N - \alpha) where Ξ±β‰₯0\alpha \geq 0 is a quantity which depends on the amount of redundancy that the SLP captures with respect to substrings of SS of a certain length. Since m=O(N/log⁑σN)m = O(N/\log_\sigma N) where Οƒ\sigma is the alphabet size, the latter is asymptotically at least as fast as a linear time algorithm which runs on the uncompressed string when Οƒ\sigma is constant, and can be more efficient when the text is compressible, i.e. when mm and nn are small.Comment: SPIRE 201

    One-variable word equations in linear time

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    In this paper we consider word equations with one variable (and arbitrary many appearances of it). A recent technique of recompression, which is applicable to general word equations, is shown to be suitable also in this case. While in general case it is non-deterministic, it determinises in case of one variable and the obtained running time is O(n + #_X log n), where #_X is the number of appearances of the variable in the equation. This matches the previously-best algorithm due to D\k{a}browski and Plandowski. Then, using a couple of heuristics as well as more detailed time analysis the running time is lowered to O(n) in RAM model. Unfortunately no new properties of solutions are shown.Comment: submitted to a journal, general overhaul over the previous versio

    The effects of the spontaneous presence of a spouse/partner and others on cardiovascular reactions to an acute psychological challenge

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    The presence of supportive others has been associated with attenuated cardiovascular reactivity in the laboratory. The effects of the presence of a spouse and others in a more naturalistic setting have received little attention. Blood pressure and heart rate reactions to mental stress were recorded at home in 1028 married/partnered individuals. For 112 participants, their spouse/partner was present; for 78, at least one other person was present. Women tested with a spouse/partner present showed lower magnitude systolic blood pressure and heart rate reactivity than those tested without. Individuals tested with at least one nonspousal other present also displayed attenuated reactivity. This extends the results of laboratory studies and indicates that the spontaneous presence of others is associated with a reduction in cardiovascular reactivity in an everyday environment; spouse/partner presence would appear to be especially effective for women.\ud \u

    Structural Principles in Robo Activation and Auto-Inhibition

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    This is the author accepted manuscript. The final version is available from Elsevier (Cell Press) via the DOI in this record.Proper brain function requires high-precision neuronal expansion and wiring, processes controlled by the transmembrane Roundabout (Robo) receptor family and their Slit ligands. Despite their great importance, the molecular mechanism by which Robos’ switch from β€œoff” to β€œon” states remains unclear. Here, we report a 3.6 Γ… crystal structure of the intact human Robo2 ectodomain (domains D1–8). We demonstrate that Robo cis dimerization via D4 is conserved through hRobo1, 2, and 3 and the C. elegans homolog SAX-3 and is essential for SAX-3 function in vivo. The structure reveals two levels of auto-inhibition that prevent premature activation: (1) cis blocking of the D4 dimerization interface and (2) trans interactions between opposing Robo receptors that fasten the D4-blocked conformation. Complementary experiments in mouse primary neurons and C. elegans support the auto-inhibition model. These results suggest that Slit stimulation primarily drives the release of Robo auto-inhibition required for dimerization and activation.ICRFIS

    Risk of Early Death in Adolescents and Young Adults With Cancer: A Population-Based Study

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    BACKGROUND: Advancements in treatment and supportive care have led to improved survival for adolescents and young adults (AYAs) with cancer; however, a subset of those diagnosed remain at risk for early death (within 2 months of diagnosis). Factors that place AYAs at increased risk of early death have not been well studied. METHODS: The Surveillance, Epidemiology, and End Results registry was used to assess risk of early death in AYAs with hematologic malignancies, central nervous system tumors, and solid tumors. Associations between age at diagnosis, sex, race, ethnicity, socioeconomic status, insurance status, rurality, and early death were assessed. RESULTS: A total of 268β€Š501 AYAs diagnosed between 2000 and 2016 were included. Early death percentage was highest in patients diagnosed with hematologic malignancies (3.1%, 95% confidence interval [CI] = 2.9% to 3.2%), followed by central nervous system tumors (2.5%, 95% CI = 2.3% to 2.8%), and solid tumors (1.0%, 95% CI = 0.9% to 1.0%). Age at diagnosis, race, ethnicity, lower socioeconomic status, and insurance status were associated with increased risk of early death in each of the cancer types. For AYAs with hematologic malignancies and solid tumors, risk of early death decreased statistically significantly over time. CONCLUSIONS: A subset of AYAs with cancer remains at risk for early death. In addition to cancer type, sociodemographic factors also affect risk of early death. A better understanding of the interplay of factors related to cancer type, treatment, and health systems that place certain AYA subsets at higher risk for early death is needed to address these disparities and improve outcomes

    The association of health literacy with adherence in older 2 adults, and its role in interventions: a systematic meta-review

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    Background: Low health literacy is a common problem among older adults. It is often suggested to be associated with poor adherence. This suggested association implies a need for effective adherence interventions in low health literate people. However, previous reviews show mixed results on the association between low health literacy and poor adherence. A systematic meta-review of systematic reviews was conducted to study the association between health literacy and adherence in adults above the age of 50. Evidence for the effectiveness of adherence interventions among adults in this older age group with low health literacy was also explored. Methods: Eight electronic databases (MEDLINE, ERIC, EMBASE, PsycINFO, CINAHL, DARE, the Cochrane Library, and Web of Knowledge) were searched using a variety of keywords regarding health literacy and adherence. Additionally, references of identified articles were checked. Systematic reviews were included if they assessed the association between health literacy and adherence or evaluated the effectiveness of interventions to improve adherence in adults with low health literacy. The AMSTAR tool was used to assess the quality of the included reviews. The selection procedure, data-extraction, and quality assessment were performed by two independent reviewers. Seventeen reviews were selected for inclusion. Results: Reviews varied widely in quality. Both reviews of high and low quality found only weak or mixed associations between health literacy and adherence among older adults. Reviews report on seven studies that assess the effectiveness of adherence interventions among low health literate older adults. The results suggest that some adherence interventions are effective for this group. The interventions described in the reviews focused mainly on education and on lowering the health literacy demands of adherence instructions. No conclusions could be drawn about which type of intervention could be most beneficial for this population. Conclusions: Evidence on the association between health literacy and adherence in older adults is relatively weak. Adherence interventions are potentially effective for the vulnerable population of older adults with low levels of health literacy, but the evidence on this topic is limited. Further research is needed on the association between health literacy and general health behavior, and on the effectiveness of interventions

    Having a lot of a good thing: multiple important group memberships as a source of self-esteem.

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    Copyright: Β© 2015 Jetten et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are creditedMembership in important social groups can promote a positive identity. We propose and test an identity resource model in which personal self-esteem is boosted by membership in additional important social groups. Belonging to multiple important group memberships predicts personal self-esteem in children (Study 1a), older adults (Study 1b), and former residents of a homeless shelter (Study 1c). Study 2 shows that the effects of multiple important group memberships on personal self-esteem are not reducible to number of interpersonal ties. Studies 3a and 3b provide longitudinal evidence that multiple important group memberships predict personal self-esteem over time. Studies 4 and 5 show that collective self-esteem mediates this effect, suggesting that membership in multiple important groups boosts personal self-esteem because people take pride in, and derive meaning from, important group memberships. Discussion focuses on when and why important group memberships act as a social resource that fuels personal self-esteem.This study was supported by 1. Australian Research Council Future Fellowship (FT110100238) awarded to Jolanda Jetten (see http://www.arc.gov.au) 2. Australian Research Council Linkage Grant (LP110200437) to Jolanda Jetten and Genevieve Dingle (see http://www.arc.gov.au) 3. support from the Canadian Institute for Advanced Research Social Interactions, Identity and Well-Being Program to Nyla Branscombe, S. Alexander Haslam, and Catherine Haslam (see http://www.cifar.ca)

    Nonlocality activation in a photonic quantum network

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    Bell nonlocality refers to correlations between two distant, entangled particles that challenge classical notions of local causality. Beyond its foundational significance, nonlocality is crucial for device-independent technologies like quantum key distribution and randomness generation. Nonlocality quickly deteriorates in the presence of noise, and restoring nonlocal correlations requires additional resources. These often come in the form of many instances of the input state and joint measurements, incurring a significant resource overhead. Here, we experimentally demonstrate that single copies of Bell-local states, incapable of violating any standard Bell inequality, can give rise to nonlocality after being embedded into a quantum network of multiple parties. We subject the initial entangled state to a quantum channel that broadcasts part of the state to two independent receivers and certify the nonlocality in the resulting network by violating a tailored Bell-like inequality. We obtain these results without making any assumptions about the prepared states, the quantum channel, or the validity of quantum theory. Our findings have fundamental implications for nonlocality and enable the practical use of nonlocal correlations in real-world applications, even in scenarios dominated by noise.Comment: Main text and Supplementary Information. Comments welcom

    Socio-Economic Status and Pregnancy Outcome: An Australian Study

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    A prospective cohort of 8556 pregnant women attending the Mater Misericordiae Mothers' Hospital in Brisbane was examined to consider the impact of socio-economic status on pregnancy outcome. The indicators of socio-economic status selected were family income, maternal education and paternal occupational status. Pregnancy outcomes considered were preterm delivery, low birthweight, low birthweight for gestational age, and perinatal death. Subsidiary analyses were also undertaken for Apgar scores, time to establish respiration, need for mechanical respiration and admission to intensive care. Before adjustment, the main consistent association was between the occupational status of the father and three measures of perinatal morbidity. Initial adjustment for the mother's socio-demographic background and weight/height ratio reduced the strength and statistical significance of the above associations, while further adjustment for lifestyle variations between the three status groups further reduced the above associations to marginal statistical significance. The findings suggest that observed class differences in pregnancy outcome are attributable to the mother's personal characteristics (height/weight, parity) and her lifestyle
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