Fast Searching in Packed Strings

Given strings $P$ and $Q$ the (exact) string matching problem is to find all positions of substrings in $Q$ matching $P$. The classical Knuth-Morris-Pratt algorithm [SIAM J. Comput., 1977] solves the string matching problem in linear time which is optimal if we can only read one character at the time. However, most strings are stored in a computer in a packed representation with several characters in a single word, giving us the opportunity to read multiple characters simultaneously. In this paper we study the worst-case complexity of string matching on strings given in packed representation. Let $m \leq n$ be the lengths $P$ and $Q$, respectively, and let $\sigma$ denote the size of the alphabet. On a standard unit-cost word-RAM with logarithmic word size we present an algorithm using time O\left(\frac{n}{\log_\sigma n} + m + \occ\right). Here \occ is the number of occurrences of $P$ in $Q$. For $m = o(n)$ this improves the $O(n)$ bound of the Knuth-Morris-Pratt algorithm. Furthermore, if $m = O(n/\log_\sigma n)$ our algorithm is optimal since any algorithm must spend at least \Omega(\frac{(n+m)\log \sigma}{\log n} + \occ) = \Omega(\frac{n}{\log_\sigma n} + \occ) time to read the input and report all occurrences. The result is obtained by a novel automaton construction based on the Knuth-Morris-Pratt algorithm combined with a new compact representation of subautomata allowing an optimal tabulation-based simulation.Comment: To appear in Journal of Discrete Algorithms. Special Issue on CPM 200

Faster Approximate String Matching for Short Patterns

We study the classical approximate string matching problem, that is, given strings $P$ and $Q$ and an error threshold $k$, find all ending positions of substrings of $Q$ whose edit distance to $P$ is at most $k$. Let $P$ and $Q$ have lengths $m$ and $n$, respectively. On a standard unit-cost word RAM with word size $w \geq \log n$ we present an algorithm using time $$O(nk \cdot \min(\frac{\log^2 m}{\log n},\frac{\log^2 m\log w}{w}) + n)$$ When $P$ is short, namely, $m = 2^{o(\sqrt{\log n})}$ or $m = 2^{o(\sqrt{w/\log w})}$ this improves the previously best known time bounds for the problem. The result is achieved using a novel implementation of the Landau-Vishkin algorithm based on tabulation and word-level parallelism.Comment: To appear in Theory of Computing System

Faster Regular Expression Matching

Abstract. Regular expression matching is a key task (and often the computational bottleneck) in a variety of widely used software tools and applications, for instance, the unix grep and sed commands, scripting languages such as awk and perl, programs for analyzing massive data streams, etc. We show how to solve this ubiquitous task in linear space and O(nm(log log n)/(logn)3/2+n+m) time where m is the length of the expression and n the length of the string. This is the first improvement for the dominant O(nm / logn) term in Myers ’ O(nm / logn+ (n+m) logn) bound [JACM 1992]. We also get improved bounds for external memory.

Understanding preventive behaviors among mid-Western African-American men: a pilot qualitative study of prostate screening

http://dx.doi.org/10.1016/j.jomh.2011.03.00

Black women are more likely than white women to schedule a uterine-sparing treatment for leiomyomas

Background: To evaluate differences in the proportion of uterine fibroid (UF) treatments that are uterine-sparing between Black women and White women and identify factors that could explain disparities. Methods: Women at age 18-54 years who were enrolled from 10 clinical sites in the United States into the Comparing Options for Management: Patient-Centered Results for UFs (COMPARE-UF) treatment registry completed questionnaires before their UF procedure. UF symptoms and quality of life were assessed by questionnaires. Details on UF imaging and treatment (hysterectomy, myomectomy, or uterine artery embolization [UAE]) were collected from each patient's medical record. Random-effects logistic regression was used to assess the association between race and the odds of having a uterine-sparing procedure versus hysterectomy. Subgroup analyses compared each uterine-sparing procedure with hysterectomy. Results: In this cohort of 1141 White women and 1196 Black women, Black women tended to be younger (median 41.0 vs. 42.0 years) and report worse symptoms, pain, and function on every scale compared with White women. Black women were more likely to have had a prior UF treatment compared with White women (22.8% vs. 14.6%). White women had more hysterectomies (43.6% vs. 32.2%) and myomectomies (50.9% vs. 50.2%) versus Black women. Black women had more UAEs (15.1% vs. 4.7%) than White women. After adjusting for clinical site and other variables, Black women had greater odds than White women of having a myomectomy (odds ratio [OR] = 2.41, 95% confidence interval [CI] = 1.63-3.56) or a UAE versus hysterectomy (OR = 4.24, 95% CI = 2.41-7.46). Conclusion: In these participants, Black women were more likely to schedule a uterine-sparing UF treatment and a nonsurgical UF treatment than their White counterparts; this may not be true for all women. Longer comparative effectiveness studies are needed to inform women about the durability of UF treatments. Greater understanding of factors influencing treatment selection is needed as are studies that include women without access to tertiary care centers. Clinical Trial Registration: Clinicaltrials.gov, NCT02260752 (enrollment start: November 2015)

Empowerment/sexism: Figuring female sexual agency in contemporary advertising

This paper argues that there has been a significant shift in advertising representations of women in recent years, such that rather than being presented as passive objects of the male gaze, young women in adverts are now frequently depicted as active, independent and sexually powerful. This analysis examines contemporary constructions of female sexual agency in advertisements examining three recognizable ‘figures’: the young, heterosexually desiring ‘midriff’, the vengeful woman set on punishing her partner or ex partner for his transgressions, and the ‘hot lesbian’, almost always entwined with her beautiful Other or double. Using recent examples of adverts the paper asks how this apparent ‘agency’ and ‘empowerment’ should be understood. Drawing on accounts of the incorporation or recuperation of feminist ideas in advertising the paper takes a critical approach to these representations, examining their exclusions, their constructions of gender relations and heteronormativity, and the way power is figured within them. A feminist poststructuralist approach is used to interrogate the way in which ‘sexual agency’ becomes a form of regulation in these adverts, that requires the re-moulding of feminine subjectivity to fit the current postfeminist, neoliberal moment in which young women should not only be beautiful but sexy, sexually knowledgeable/practised and always ‘up for it’. The paper makes an original contribution to debates about representations of gender in advertising, to poststructuralist analyses about the contemporary operation of power, and to writing about female ‘sexual agency’ by suggesting that ‘voice’ or ‘agency’ may not be the solution to the ‘missing discourse of female desire' but may in fact be a technology of discipline and regulation

Biology, Fishery, Conservation and Management of Indian Ocean Tuna Fisheries

The focus of the study is to explore the recent trend of the world tuna fishery with special reference to the Indian Ocean tuna fisheries and its conservation and sustainable management. In the Indian Ocean, tuna catches have increased rapidly from about 179959 t in 1980 to about 832246 t in 1995. They have continued to increase up to 2005; the catch that year was 1201465 t, forming about 26% of the world catch. Since 2006 onwards there has been a decline in the volume of catches and in 2008 the catch was only 913625 t. The Principal species caught in the Indian Ocean are skipjack and yellowfin. Western Indian Ocean contributed 78.2% and eastern Indian Ocean 21.8% of the total tuna production from the Indian Ocean. The Indian Ocean stock is currently overfished and IOTC has made some recommendations for management regulations aimed at sustaining the tuna stock. Fishing operations can cause ecological impacts of different types: by catches, damage of the habitat, mortalities caused by lost or discarded gear, pollution, generation of marine debris, etc. Periodic reassessment of the tuna potential is also required with adequate inputs from exploratory surveys as well as commercial landings and this may prevent any unsustainable trends in the development of the tuna fishing industry in the Indian Ocean

Sociocultural considerations in aging men's health: implications and recommendations for the clinician

http://dx.doi.org/10.1016/j.jomh.2009.07.00

On the Holographic RG-flow and the Low-energy, Strong Coupling, Large N Limit

From the AdS/CFT correspondence, we learn that the classical evolution of supergravity in the bulk can be reduced to a RG-flow equation for the dual low-energy, strongly coupled and large N gauge theory on the boundary. This result has been used to obtain interesting relations between the various terms in the gravitational part of the boundary effective action, in particular the term that affect the cosmological constant. It is found that once the cosmological constant is cancelled in the UV theory, the RG-flow symmetry of the boundary effective action automatically implies the existence of zero cosmological constant solutions that extend all the way into the IR. Given the standard (and well founded) contradiction between the RG-flow idea and the observational evidence of a small cosmological constant, this is considered to be an important progress, albeit incomplete, towards the final solution. Motivated by this success, it would be interesting to see whether this RG-stability extends outside the scope of strong 't Hooft coupling and large N regime that are implicitly assumed in the de Boer-Verlinde-Verlinde Hamilton-Jacobi formulation of the holographic RG-flow equations of the boundary theory. In this paper, we address this question. Taking into account the leading order corrections in the 1/N and $\alpha'/{R^2}$ parameters, we derive new bulk/boundary relations, from which one can read all the local terms in the boundary effective action. Next, we use the resulting constraints, to examine whether the RG-stability of the cosmological constant extends to the new coupling regime. It would be also interesting to use these constraints to study the Randall-Sundrum scenario in this case.Comment: 27 pages, LateX, no figures, minor changes, typos corrected and added more reference