New Variants of Pattern Matching with Constants and Variables

Given a text and a pattern over two types of symbols called constants and variables, the parameterized pattern matching problem is to find all occurrences of substrings of the text that the pattern matches by substituting a variable in the text for each variable in the pattern, where the substitution should be injective. The function matching problem is a variant of it that lifts the injection constraint. In this paper, we discuss variants of those problems, where one can substitute a constant or a variable for each variable of the pattern. We give two kinds of algorithms for both problems, a convolution-based method and an extended KMP-based method, and analyze their complexity.Comment: 15 pages, 2 figure

Complexity and Inapproximability Results for Parallel Task Scheduling and Strip Packing

We study the Parallel Task Scheduling problem $Pm|size_j|C_{\max}$ with a constant number of machines. This problem is known to be strongly NP-complete for each $m \geq 5$, while it is solvable in pseudo-polynomial time for each $m \leq 3$. We give a positive answer to the long-standing open question whether this problem is strongly $NP$-complete for $m=4$. As a second result, we improve the lower bound of $\frac{12}{11}$ for approximating pseudo-polynomial Strip Packing to $\frac{5}{4}$. Since the best known approximation algorithm for this problem has a ratio of $\frac{4}{3} + \varepsilon$, this result narrows the gap between approximation ratio and inapproximability result by a significant step. Both results are proven by a reduction from the strongly $NP$-complete problem 3-Partition

Two Years Later: Journals Are Not Yet Enforcing the ARRIVE Guidelines on Reporting Standards for Pre-Clinical Animal Studies

There is growing concern that poor experimental design and lack of transparent reporting contribute to the frequent failure of pre-clinical animal studies to translate into treatments for human disease. In 2010, the Animal Research: Reporting of In Vivo Experiments (ARRIVE) guidelines were introduced to help improve reporting standards. They were published in PLOS Biology and endorsed by funding agencies and publishers and their journals, including PLOS, Nature research journals, and other top-tier journals. Yet our analysis of papers published in PLOS and Nature journals indicates that there has been very little improvement in reporting standards since then. This suggests that authors, referees, and editors generally are ignoring guidelines, and the editorial endorsement is yet to be effectively implemented

SEX-SPECIFIC MUSCULOSKELETAL ASYMMETRIES FOLLOWING ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

Olivia A. Anderson 1, Allen L. Redinger1, Emery L. Mintz 2,3, Caleb C. Voskuil 2, Jason A. Mogonye 3,4, Joshua C. Carr 2,3 & Breanne S. Baker 1 1 Oklahoma State University, Stillwater, Oklahoma; 2 Texas Christian University, Fort Worth, Texas; 3 Texas Christian University School of Medicine, Fort Worth, Texas; 4 JPS Health Network, Fort Worth, Texas Females are predisposed to more risk factors for primary and secondary anterior cruciate ligament (ACL) injury. Factors such as lower-body bone, muscle, and fat tissue asymmetries post-ACL reconstruction (ACLR) influence recovery; however, if these asymmetries are sex-specific is unknown. PURPOSE: This study aimed to evaluate the influence of sex on musculoskeletal asymmetries and perception of knee function post-ACLR. METHODS: Females (n=11) and males (n=11) with a history of ACLR provided voluntary informed consent prior to completing Dual-energy X-ray Absorptiometry (DXA) scans to measure lower-body bone mineral content (BMC), Fat %, and lean mass (LM), additionally inter-limb asymmetry indices (AI%) were calculated for each tissue. Perceptions of knee function were captured via the International Knee Documentation Committee (IKDC) instrument and participants provided surgical information such as time since surgery and graft type used. Initial Independent t-tests were used to assess sex differences for all variables; however, time since surgery was included as a clinically significant covariate for subsequent analyses. Additionally, Pearson’s Correlations Coefficients evaluated the association between AI% and IKDC scores. Lastly, Cohen’s effect sizes (d) were calculated and α=0.05. RESULTS: Females had greater asymmetries for BMC and LM and lower IKDC scores compared to males post-ACLR (adjusted p≤0.027, d=0.40–0.74). Furthermore, a sex-dependent correlation was observed as tissue asymmetries were negatively correlated with IKDC scores for only females (all r≥0.755; p≤0.007). CONCLUSIONS: These data suggested females with a history of ACLR have greater musculoskeletal tissue asymmetries compared to males, which are associated with lower perceptions of knee function. As such, sex-specific ACLR rehabilitation and musculoskeletal monitoring protocols may need to be developed as we aim to reduce females’ elevated risk for ACL reinjury

Direct measurement of piston friction of internal-combustion engines using the floating-liner principle

Piston–cylinder interactions account for a significant portion of frictional losses in an internal-combustion engine. This is mainly as the result of significant changes in the operating conditions (the load, the speed and the temperature) as well as the contact geometry and the encountered topography during a typical engine cycle. These changes alter the regime of lubrication which underlies the mechanisms of friction generation. The multi-variate interactive nature of the problem requires quite complex analyses which do not fully replicate the actual in-situ conditions. Therefore, there is a need for direct measurement of cyclic friction under controlled conditions. The paper describes the use of a novel floating-liner arrangement which is capable of direct measurement of friction, its transitory mechanisms, as well as determination of the regime of lubrication

Optimality program in segment and string graphs

Planar graphs are known to allow subexponential algorithms running in time $2^{O(\sqrt n)}$ or $2^{O(\sqrt n \log n)}$ for most of the paradigmatic problems, while the brute-force time $2^{\Theta(n)}$ is very likely to be asymptotically best on general graphs. Intrigued by an algorithm packing curves in $2^{O(n^{2/3}\log n)}$ by Fox and Pach [SODA'11], we investigate which problems have subexponential algorithms on the intersection graphs of curves (string graphs) or segments (segment intersection graphs) and which problems have no such algorithms under the ETH (Exponential Time Hypothesis). Among our results, we show that, quite surprisingly, 3-Coloring can also be solved in time $2^{O(n^{2/3}\log^{O(1)}n)}$ on string graphs while an algorithm running in time $2^{o(n)}$ for 4-Coloring even on axis-parallel segments (of unbounded length) would disprove the ETH. For 4-Coloring of unit segments, we show a weaker ETH lower bound of $2^{o(n^{2/3})}$ which exploits the celebrated Erd\H{o}s-Szekeres theorem. The subexponential running time also carries over to Min Feedback Vertex Set but not to Min Dominating Set and Min Independent Dominating Set.Comment: 19 pages, 15 figure

Markers for early detection of cancer: Statistical guidelines for nested case-control studies

BACKGROUND: Recently many long-term prospective studies have involved serial collection and storage of blood or tissue specimens. This has spurred nested case-control studies that involve testing some specimens for various markers that might predict cancer. Until now there has been little guidance in statistical design and analysis of these studies. METHODS: To develop statistical guidelines, we considered the purpose, the types of biases, and the opportunities for extracting additional information. RESULTS: The following guidelines: (1) For the clearest interpretation, statistics should be based on false and true positive rates – not odds ratios or relative risks (2) To avoid overdiagnosis bias, cases should be diagnosed as a result of symptoms rather than on screening. (3) To minimize selection bias, the spectrum of control conditions should be the same in study and target screening populations. (4) To extract additional information, criteria for a positive test should be based on combinations of individual markers and changes in marker levels over time. (5) To avoid overfitting, the criteria for a positive marker combination developed in a training sample should be evaluated in a random test sample from the same study and, if possible, a validation sample from another study. (6) To identify biomarkers with true and false positive rates similar to mammography, the training, test, and validation samples should each include at least 110 randomly selected subjects without cancer and 70 subjects with cancer. CONCLUSION: These guidelines ensure good practice in the design and analysis of nested case-control studies of early detection biomarkers