String attractors and combinatorics on words

The notion of string attractor has recently been introduced in [Prezza, 2017] and studied in [Kempa and Prezza, 2018] to provide a unifying framework for known dictionary-based compressors. A string attractor for a word w = w[1]w[2] · · · w[n] is a subset Γ of the positions 1, . . ., n, such that all distinct factors of w have an occurrence crossing at least one of the elements of Γ. While finding the smallest string attractor for a word is a NP-complete problem, it has been proved in [Kempa and Prezza, 2018] that dictionary compressors can be interpreted as algorithms approximating the smallest string attractor for a given word. In this paper we explore the notion of string attractor from a combinatorial point of view, by focusing on several families of finite words. The results presented in the paper suggest that the notion of string attractor can be used to define new tools to investigate combinatorial properties of the words

Evaluation of the burden of HPV-related hospitalizations as a useful tool to increase awareness: 2007–2017 data from the sicilian hospital discharge records

In light of the implementation of human papillomavirus (HPV) prevention strategies, epidemiological studies in different geographical areas are required in order to assess the impact of HPV-related diseases. The purpose of the present study was to describe the burden of HPV-related hospitalizations in Sicily. A retrospective observational study estimated 43,531 hospitalizations attributable to HPV from 2007 to 2017. During the observed period, there was a decrease for all HPV-related conditions with a higher reduction, among neoplasms, for cervical cancer (annual percent change (APC) = −9.9%, p < 0.001). The median age for cervical cancer was 45 years old, with an increasing value from 43 to 47 years (p < 0.001). The age classes with greater decreases in hospital admissions for invasive cancers were women aged 35 years or more (APC range from −5.5 to −9.86) and 25–34 years old (APC = −11.87, p < 0.001) for women with cervical carcinoma in situ. After ten years for vaccine introduction and sixteen years for cervical cancer screening availability, a relatively large decrease in hospital admissions for cervical cancer and other HPV-related diseases in Sicily was observed. Some clinical characteristics of hospitalization, such as increasing age, are suggestive clues for the impact of preventive strategies, but further research is needed to confirm this relationship

Symmetric Groups and Quotient Complexity of Boolean Operations

The quotient complexity of a regular language L is the number of left quotients of L, which is the same as the state complexity of L. Suppose that L and L' are binary regular languages with quotient complexities m and n, and that the transition semigroups of the minimal deterministic automata accepting L and L' are the symmetric groups S_m and S_n of degrees m and n, respectively. Denote by o any binary boolean operation that is not a constant and not a function of one argument only. For m,n >= 2 with (m,n) not in {(2,2),(3,4),(4,3),(4,4)} we prove that the quotient complexity of LoL' is mn if and only either (a) m is not equal to n or (b) m=n and the bases (ordered pairs of generators) of S_m and S_n are not conjugate. For (m,n)\in {(2,2),(3,4),(4,3),(4,4)} we give examples to show that this need not hold. In proving these results we generalize the notion of uniform minimality to direct products of automata. We also establish a non-trivial connection between complexity of boolean operations and group theory

Association of the Individual and Context Inequalities on the Breastfeeding: A Study from the Sicily Region

Despite the advantages of breastfeeding being widely recognized, the economic level can have an influence on breastfeeding rates, with rich women breastfeeding longer than poor in high-income countries. In Italy, socio-economic differences affect breastfeeding start and continuation among most deprived people, such as in Southern Italy. The objective of the study was to evaluate the prevalence of the initiation and continuation of exclusive breastfeeding and its association with the levels of socio-economic deprivation in Sicily. A prospective cohort study with a two-phase survey in three breastfeeding detection times was conducted. Overall, 1,055 mothers were recruited with a mean age of 31 years. Breastfeeding decreased from 86% during hospitalization to 69% at the first month and 42% at the sixth month, yet at the same time, exclusive breastfeeding increased from 34% to 38% during hospitalization to the first month and went down to 20.2% at the sixth month. The adjusted multivariate analysis showed no association with individual inequalities. On the other hand, the context inequalities had a significant association with the risk of not following exclusive breastfeeding in the deprived class (odds ratio (OR): 2.08, confidence interval (CI) 95% 1.01-4.27) and in the very deprived class (OR: 1.83, CI 95% 1.00-3.38) at the six-month survey. These results indicate that the context inequalities begin to emerge from the return home of the mother and the child

Sorting conjugates and Suffixes of Words in a Multiset

In this paper we are interested in the study of the combinatorial aspects related to the extension of the Burrows-Wheeler transform to a multiset of words. Such study involves the notion of suffixes and conjugates of words and is based on two different order relations, denoted by <_lex and ≺_ω, that, even if strictly connected, are quite different from the computational point of view. In particular, we introduce a method that only uses the <_lex sorting among suffixes of a multiset of words in order to sort their conjugates according to ≺_ω-order. In this study an important role is played by Lyndon words. This strategy could be used in applications specially in the field of Bioinformatics, where for instance the advent of "next-generation" DNA sequencing technologies has meant that huge collections of DNA sequences are now commonplace

Episodic breathlessness with and without background dyspnea in advanced cancer patients admitted to an acute supportive care unit

Aim: To characterize episodic breathlessness (EB) in patients with advanced cancer, and to determine factors influencing its clinical appearance. Methods: A consecutive sample of advanced cancer patients admitted to an acute palliative care unit was surveyed. Continuous dyspnea and EB were measured by a numerical scale. The use of drugs used for continuous dyspnea and EB was recorded. Patients were asked about the characteristics of EB (frequency, intensity, duration and triggers). The Multidimensional dyspnea profile (MDP), the Brief dyspnea inventory (BDI), the Athens sleep scale (AIS) and the Hospital Anxiety and Depression Scale (HADS) were also administered. Results: From 439 advanced cancer patients surveyed, 34 and 27 patients had EB, without and with background dyspnea, respectively. The mean intensity and the number of episodes were higher in patients with background dyspnea (p &lt; 0.0005 and p = 0.05, respectively). No differences in duration were observed. Most episodes lasted &lt;10 min. A recognizable cause triggering EB was often found. The presence of both background dyspnea and EB was associated with higher values of MDP and BDI. EB was independently associated with frequency and intensity of background dyspnea (OR = 20.9, 95% CI (Confidence interval) 9.1–48.0; p &lt; 0.0005 and OR = 1.97, 95% CI 1.09–3.58; p = 0.025, respectively) and a lower Karnofsky level (OR = 0.96, 95%CI 0.92–0.98, p = 0.05). Discussion: EB may occur in patients with and without continuous dyspnea, and is often induced by physical and psychological factors. EB intensity is higher in patients with continuous dyspnea. The duration was often so short that the use of drugs, as needed, may be too late, unless administered pre-emptively when the trigger was predictable

Accuracy of Siri and Brozek equations in the percent body fat estimation in older adults

To identify which equation, Siri or Brozek, based on the two compartment model, provides a more accurate conversion of body density (BD) in percent body fat (%BF) in a group of older adults. Cross-sectional study. Research Centre in Physical Activity, Health and Leisure, Faculty of Sport, University of Porto. 60 older adults, aged 60-92 years. Skinfold thickness was used to estimate BD through Visser et al. prediction equation. The conversion of BD to %BF was done with Siri (%BF-Siri) and Brozek (%BF-Brozek) formulas and these determined values were both compared to Dual-Energy X-ray Absorptiometry (%BF-DXA) evaluations. A strong correlation between the %BF-DXA value and %BF-Siri (r=0.91, p < 0.001) and %BF-Brozek (r=0.91, p < 0.001) was found, although %BF-Siri and %BF-Brozek overestimated %BF-DXA (p < 0.001). The comparison of the %BF-Siri and %BF-Brozek mean values also revealed significant differences (p < 0.001). The %BF-Brozek reflects a better agreement than the %BF-Siri with %BF-DXA with respectively a mean difference of -4.0%BF (limits of agreement = -10.9 to 2.9%) and -5.7%BF (-12.6 to 1.2). The Bland and Altman plots confirmed that %BF-Brozek reflects a better agreement with %BF-DXA. The results of the present study show that the use of Brozek equation may correspond to a more accurate alternative than Siri equation for the conversion of BD in %BF in older adults

Utilization of Interactive Internet in High Education

The present work reports on the practical cooperation between two Universities from Hungary and Portugal. Students from Portugal are remotely accessing an experimental facility, which is physically in Hungary. The cooperation among these Higher Education establishments allowed the development and testing of a Remote Laboratory at the BME. This paper reports on the characteristics and initial testing of the Thermocouples Rise Time Measurement System and provides information on development and students' feedback