1,118 research outputs found

    Fibromyalgia, myofascial pain, tender points and trigger points: splitting or lumping?

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    Myofascial trigger points (MTPs) have long been a contentious issue in relation to fibromyalgia, and poorly defined pain complaints in general. Can MTPs be reproducibly identified? Do MTPs have valid objective findings, such as spontaneous electromyographic activity, muscle microdialysis evidence for an inflammatory milieu or visualization with newer ultrasound techniques? Is fibromyalgia a syndrome of multiple MTPs, or is focal muscle tenderness a manifestation of central sensitization? These issues are discussed with relevance to a recent paper reporting that manual palpation of active MTPs elicits the spontaneous pain experienced by fibromyalgia patients

    An Algorithmic Bridge Between Hamming and Levenshtein Distances

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    The edit distance between strings classically assigns unit cost to every character insertion, deletion, and substitution, whereas the Hamming distance only allows substitutions. In many real-life scenarios, insertions and deletions (abbreviated indels) appear frequently but significantly less so than substitutions. To model this, we consider substitutions being cheaper than indels, with cost 1/a1/a for a parameter a≥1a\ge 1. This basic variant, denoted EDaED_a, bridges classical edit distance (a=1a=1) with Hamming distance (a→∞a\to\infty), leading to interesting algorithmic challenges: Does the time complexity of computing EDaED_a interpolate between that of Hamming distance (linear time) and edit distance (quadratic time)? What about approximating EDaED_a? We first present a simple deterministic exact algorithm for EDaED_a and further prove that it is near-optimal assuming the Orthogonal Vectors Conjecture. Our main result is a randomized algorithm computing a (1+ϵ)(1+\epsilon)-approximation of EDa(X,Y)ED_a(X,Y), given strings X,YX,Y of total length nn and a bound k≥EDa(X,Y)k\ge ED_a(X,Y). For simplicity, let us focus on k≥1k\ge 1 and a constant ϵ>0\epsilon > 0; then, our algorithm takes O~(n/a+ak3)\tilde{O}(n/a + ak^3) time. Unless a=O~(1)a=\tilde{O}(1) and for small enough kk, this running time is sublinear in nn. We also consider a very natural version that asks to find a (kI,kS)(k_I, k_S)-alignment -- an alignment with at most kIk_I indels and kSk_S substitutions. In this setting, we give an exact algorithm and, more importantly, an O~(nkI/kS+kS⋅kI3)\tilde{O}(nk_I/k_S + k_S\cdot k_I^3)-time (1,1+ϵ)(1,1+\epsilon)-bicriteria approximation algorithm. The latter solution is based on the techniques we develop for EDaED_a for a=Θ(kS/kI)a=\Theta(k_S / k_I). These bounds are in stark contrast to unit-cost edit distance, where state-of-the-art algorithms are far from achieving (1+ϵ)(1+\epsilon)-approximation in sublinear time, even for a favorable choice of kk.Comment: The full version of a paper accepted to ITCS 2023; abstract shortened to meet arXiv requirement

    Gap Edit Distance via Non-Adaptive Queries: Simple and Optimal

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    We study the problem of approximating edit distance in sublinear time. This is formalized as a promise problem (k,kc)(k,k^c)-Gap Edit Distance, where the input is a pair of strings X,YX,Y and parameters k,c>1k,c>1, and the goal is to return YES if ED(X,Y)≤kED(X,Y)\leq k and NO if ED(X,Y)>kcED(X,Y)> k^c. Recent years have witnessed significant interest in designing sublinear-time algorithms for Gap Edit Distance. We resolve the non-adaptive query complexity of Gap Edit Distance, improving over several previous results. Specifically, we design a non-adaptive algorithm with query complexity O~(nkc−0.5)\tilde{O}(\frac{n}{k^{c-0.5}}), and further prove that this bound is optimal up to polylogarithmic factors. Our algorithm also achieves optimal time complexity O~(nkc−0.5)\tilde{O}(\frac{n}{k^{c-0.5}}) whenever c≥1.5c\geq 1.5. For 1<c<1.51<c<1.5, the running time of our algorithm is O~(nk2c−1)\tilde{O}(\frac{n}{k^{2c-1}}). For the restricted case of kc=Ω(n)k^c=\Omega(n), this matches a known result [Batu, Erg\"un, Kilian, Magen, Raskhodnikova, Rubinfeld, and Sami, STOC 2003], and in all other (nontrivial) cases, our running time is strictly better than all previous algorithms, including the adaptive ones

    Improving pregnancy outcomes in low- and middle-income countries

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    This paper reviews the very large discrepancies in pregnancy outcomes between high, low and middle-income countries and then presents the medical causes of maternal mortality, stillbirth and neonatal mortality in low-and middle-income countries. Next, we explore the medical interventions that were associated with the very rapid and very large declines in maternal, fetal and neonatal mortality rates in the last eight decades in high-income countries. The medical interventions likely to achieve similar declines in pregnancy-related mortality in low-income countries are considered. Finally, the quality of providers and the data to be collected necessary to achieve these reductions are discussed. It is emphasized that single interventions are unlikely to achieve important reductions in pregnancy-related mortality. Instead, improving the overall quality of pregnancy-related care across the health-care system will be necessary. The conditions that cause maternal mortality also cause stillbirths and neonatal deaths. Focusing on all three mortalities together is likely to have a larger impact than focusing on one of the mortalities alone

    An Algorithmic Bridge Between Hamming and Levenshtein Distances

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    Reducing neonatal mortality associated with preterm birth: gaps in knowledge of the impact of antenatal corticosteroids on preterm birth outcomes in low-middle income countries

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    The Global Network’s Antenatal Corticosteroids Trial (ACT), was a multi-country, cluster-randomized trial to improve appropriate use of antenatal corticosteroids (ACS) in low-resource settings in low-middle income countries (LMIC). ACT substantially increased ACS use in the intervention clusters, but the intervention failed to show benefit in the targeted < 5th percentile birth weight infants and was associated with increased neonatal mortality and stillbirth in the overall population. In this issue are six papers which are secondary analyses related to ACT that explore potential reasons for the increase in adverse outcomes overall, as well as site differences in outcomes. The African sites appeared to have increased neonatal mortality in the intervention clusters while the Guatemalan site had a significant reduction in neonatal mortality, perhaps related to a combination of ACS and improving obstetric care in the intervention clusters. Maternal and neonatal infections were increased in the intervention clusters across all sites and increased infections are a possible partial explanation for the increase in neonatal mortality and stillbirth in the intervention clusters, especially in the African sites. The analyses presented here provide guidance for future ACS trials in LMIC. These include having accurate gestational age dating of study subjects and having care givers who can diagnose conditions leading to preterm birth and predict which women likely will deliver in the next 7 days. All study subjects should be followed through delivery and the neonatal period, regardless of when they deliver. Clearly defined measures of maternal and neonatal infection should be utilized. Trials in low income country facilities including clinics and those without newborn intensive care seem to be of the highest priority.Fil: McClure, Elizabeth M.. RTI International; Estados UnidosFil: Goldenberg, Robert L.. Columbia University; Estados UnidosFil: Jobe, Alan H.. Cincinnati Children’s Hospital; Estados UnidosFil: Miodovnik, Menachem. Eunice Kennedy Shriver National Institute of Child and Human Development; Estados UnidosFil: Koso Thomas, Marion. Eunice Kennedy Shriver National Institute of Child and Human Development; Estados UnidosFil: Buekens, Pierre. University of Tulane; Estados UnidosFil: Belizan, Jose. Instituto de Efectividad Clínica y Sanitaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Althabe, Fernando. Instituto de Efectividad Clínica y Sanitaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    Commentary: reducing the world's stillbirths

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    One of the major success stories of modern obstetrics in high-income countries in the last 5 decades is the reduction of stillbirths from rates as high as 50 per 1000 births to about 5 per 1000 births today. Fetal mortality associated with obstructed labour, asphyxia, hypertension, diabetes, Rh disease, placental abruption, post-term pregnancies and infections such as syphilis all have declined. Much of this success has occurred in term births in the intrapartum period so that most stillbirths in high-income countries now occur in the antepartum period and are pre-term. Current stillbirth rates in many low- and middle-income countries, and especially in those areas within the countries with poorly functioning health systems, approximate those seen in high-income countries 50 years ago. A major difference between the stillbirths occurring in high-income countries and those occurring elsewhere is the preponderance of late pre-term, term and intrapartum stillbirths in low-resource countries. Those stillbirths should be relatively easy to prevent by known risk assessment methods and prompt delivery, often by Cesarean section. This commentary addresses an extensive six-paper review of stillbirths with an emphasis on low- and middle-income countries. Among the conclusions are that while a number of interventions have been shown to be effective in reducing stillbirths, unless there is a functioning health system in which these interventions can be implemented, the potential for a sustainable and substantial reduction in stillbirth rates will not be reached
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