From Finite Automata to Regular Expressions and Back--A Summary on Descriptional Complexity

The equivalence of finite automata and regular expressions dates back to the seminal paper of Kleene on events in nerve nets and finite automata from 1956. In the present paper we tour a fragment of the literature and summarize results on upper and lower bounds on the conversion of finite automata to regular expressions and vice versa. We also briefly recall the known bounds for the removal of spontaneous transitions (epsilon-transitions) on non-epsilon-free nondeterministic devices. Moreover, we report on recent results on the average case descriptional complexity bounds for the conversion of regular expressions to finite automata and brand new developments on the state elimination algorithm that converts finite automata to regular expressions.Comment: In Proceedings AFL 2014, arXiv:1405.527

Finite index subgroups without unique product in graphical small cancellation groups

We construct torsion-free hyperbolic groups without unique product whose subgroups up to some given finite index are themselves non-unique product groups. This is achieved by generalising a construction of Comerford to graphical small cancellation presentations, showing that for every subgroup $H$ of a graphical small cancellation group there exists a free group $F$ such that $H*F$ admits a graphical small cancellation presentation.Comment: 8 pages, 1 figur

How prior experience, cognitive skills and practice are related with eye-hand span and performance in video gaming

Research has shown that performance in visual domains depends on domain-specific cognitive and perceptual adaptations that result from extensive practice. However, less is known about processes and factors that underpin the acquisition of such adaptations. The present study investigated how prior experience, cognitive skills, task difficulty and practice effect eye-hand span (EHS) and performance in video gaming. Thirty-three participants played a platformer video game in a pre-test/practice/post-test experiment. Eye movements and keypresses were recorded. The results show that a short practice period improved performance but did not increase EHS. Instead, EHS was related to task difficulty. Furthermore, while EHS correlated with initial performance, this effect seemed to diminish after practice. Cognitive skills (concentration endurance, working memory, mental flexibility and executive functioning) predicted performance in some parts of the experiment. The study offers insights into the early development of visual adaptations and performance

Force production capacity and functional reflex activity in young and elderly men

Background and aims: There is growing evidence that biological aging results in impaired force production of the lower extremities and deficits in reflex activity. This study therefore investigated maximal and explosive force production capacity, functional reflex activity (FRA) during gait perturbations, and the relationship between variables of force production capacity and FRA in young and elderly men. Methods: Twenty-eight young (age 27±3 yrs, n=14) and old (age 67±4 yrs, n=14) healthy active men were tested for decelerating impulses on a treadmill and for their maximal isometric leg extension force (MIF) and rate of force development (RFD) on a leg-press. Results: MIF and RFD were significantly lower in the elderly than in younger participants (MIF ≈45%, p<0.01; RFD ≈50%, p<0.01). Elderly subjects showed significant decreases in FRA in the prime mover which compensated for the decelerating impulse (FRA ≈29%, p<0.05). No significant correlations were found between FRA, MIF or RFD. Conclusions: Lower MIF, RFD and impaired FRA were found in old compared with young men. The absence of significant correlations between measures of strength performance and FRA may indicate that different mechanisms within the neuromuscular system are responsible for these capacities. This result may imply that force production and functional reflex activity are independent of each other and may have to be trained complementaril

An open-label randomized clinical trial of prophylactic paracetamol coadministered with 7-valent pneumococcal conjugate vaccine and hexavalent diphtheria toxoid, tetanus toxoid, 3-component acellular pertussis, hepatitis B, inactivated poliovirus, and Haemophilus influenzae type b vaccine

BACKGROUND: In two clinical trials, low-grade fever was observed more frequently after coadministration than after separate administration of two recommended routine pediatric vaccines. Since fever is an important issue with vaccine tolerability, we performed this open-label study on the efficacy and safety of prophylactic use of paracetamol (acetaminophen, Benuron(R)) in children administered routine 7-valent pneumococcal conjugate vaccine (PCV-7) coadministered with hexavalent vaccine (diphtheria-tetanus-acellular pertussis-hepatitis B, polio, Haemophilus influenzae type b vaccine [DTPa-HBV-IPV/Hib]) in Germany. METHODS: Healthy infants (N = 301) who received a 3-dose infant series of PCV-7 and DTPa-HBV-IPV/Hib plus a toddler dose were randomly assigned 1:1 to prophylactic paracetamol (125 mg or 250 mg suppositories, based on body weight) at vaccination, and at 6--8 hour intervals thereafter, or a control group that received no paracetamol. Rectal temperature and local and other systemic reactions were measured for 4 days post vaccination; adverse events were collected throughout the study. RESULTS: In the intent-to-treat population, paracetamol reduced the incidence of fever >=38[degree sign]C, but this reduction was only significant for the infant series, with computed efficacy of 43.0% (95% confidence interval [CI]: 17.4, 61.2), and not significant after the toddler dose (efficacy 15.9%; 95% CI: -19.9, 41.3); results were similar in the per protocol (PP) population. Fever >39[degree sign]C was rare during the infant series, such that there were too few cases for assessment. After the toddler dose, paracetamol effectively reduced fever >39[degree sign]C, reaching statistical significance in the PP population only (efficacy 79%; 95% CI: 3.9, 97.7). Paracetamol also reduced reactogenicity, but there were few significant differences between groups after any dose. No vaccine-related serious adverse events were reported. CONCLUSIONS: Paracetamol effectively prevented fever and other reactions, mainly during the infant series. However, as events were generally mild and of no concern in either group our data support current recommendations to administer paracetamol to treat symptoms only and not for routine prophylaxis.Trial registration: NCT00294294