358 research outputs found
Satisfiability in multi-valued circuits
Satisfiability of Boolean circuits is among the most known and important
problems in theoretical computer science. This problem is NP-complete in
general but becomes polynomial time when restricted either to monotone gates or
linear gates. We go outside Boolean realm and consider circuits built of any
fixed set of gates on an arbitrary large finite domain. From the complexity
point of view this is strictly connected with the problems of solving equations
(or systems of equations) over finite algebras.
The research reported in this work was motivated by a desire to know for
which finite algebras there is a polynomial time algorithm that
decides if an equation over has a solution. We are also looking for
polynomial time algorithms that decide if two circuits over a finite algebra
compute the same function. Although we have not managed to solve these problems
in the most general setting we have obtained such a characterization for a very
broad class of algebras from congruence modular varieties. This class includes
most known and well-studied algebras such as groups, rings, modules (and their
generalizations like quasigroups, loops, near-rings, nonassociative rings, Lie
algebras), lattices (and their extensions like Boolean algebras, Heyting
algebras or other algebras connected with multi-valued logics including
MV-algebras).
This paper seems to be the first systematic study of the computational
complexity of satisfiability of non-Boolean circuits and solving equations over
finite algebras. The characterization results provided by the paper is given in
terms of nice structural properties of algebras for which the problems are
solvable in polynomial time.Comment: 50 page
Effectiveness of interventions to improve health behaviours of health professionals : A systematic review
Objective To evaluate the effectiveness of interventions designed to improve the health behaviours of health professionals.
Design Systematic review.
Data sources Database searches: Medline, Cochrane library, Embase and CINAHL.
Review methods This systematic review used Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to compare randomised controlled trials of health professionals, published between 2010 and 2021, which aimed to improve at least one health behaviour such as physical activity, diet, smoking status, mental health and stress. Two independent reviewers screened articles, extracted data and assessed quality of studies and reporting. The quality of articles was assessed using the Effective Public Health Practice Project quality assessment tool and the completeness of intervention reporting was assessed.
Outcome measures The outcome assessed was change in behaviour between intervention and control groups from baseline to follow-up.
Results Nine studies met the eligibility criteria, totalling 1107 participants. Health behaviours targeted were mental health and stress, physical activity, and smoking cessation, physical activity and nutrition. Six interventions observed significant improvements in the health behaviour in the intervention compared with control groups. Seven of the studies selected in person workshops as the mode of intervention delivery. The quality of the included studies was high with 80% (7/9) graded as moderate or strong.
Conclusions Although high heterogeneity was found between interventions and outcomes, promising progress has occurred across a variety of health behaviours. Improving reporting and use of theories and models may improve effectiveness and evaluation of interventions. Further investigation is needed to recommend effective strategies.
PROSPERO registration number CRD42021238684
Congruence modularity implies cyclic terms for finite algebras
An n-ary operation f : A(n) -> A is called cyclic if it is idempotent and f(a(1), a(2), a(3), ... , a(n)) = f(a(2), a(3), ... , a(n), a(1)) for every a(1), ... , a(n) is an element of A. We prove that every finite algebra A in a congruence modular variety has a p-ary cyclic term operation for any prime p greater than vertical bar A vertical bar
Mind-mindedness and preschool children’s behavioral difficulties: the moderating role of maternal parenting distress
Mind-mindedness (MM) is a caregiver’s tendency to appreciate their infant’s internal mental states. This longitudinal study investigated whether maternal MM (10 months) was linked with children’s later behavioral problems (51 months) and the moderating role of maternal parenting distress (PD; 36 months) in a sample of 91 mother–infant dyads. Appropriate MM comments were coded from video-recorded, semi-structured play interactions between mothers and their infants; PD was obtained from maternal completion of the PD subscale of the Parenting Stress Index – Short Form (PSI-SF); and child internalizing and externalizing behavior problems were gathered from maternal report on the Strengths and Difficulties Questionnaire (SDQ). Moderated regression analyses revealed higher early appropriate MM was associated with significantly fewer internalizing emotional problems at 51 months among mothers with lower PD at 36 months, and higher early appropriate MM was associated with lower conduct problems at 51 months in mothers with higher PD at 36 months. Findings demonstrated the importance of considering nuanced contexts such as at-risk mothers and differential presentations of child difficulties in the analysis of the relationship between MM and child behavioral difficulties and the development of MM interventions
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Effect of varying skin surface electrode position on electroretinogram responses recorded using a handheld stimulating and recording system
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How does age-related macular degeneration affect real-world visual ability and quality of life? A systematic review
Objectives
To review systematically the evidence of age-related macular degeneration (AMD) affecting real-world visual ability and quality of life (QoL). To explore trends in specific topics within this body of the literature.
Design
Systematic review.
Methods
A systematic literature search was carried out using MEDLINE, EMBASE, CINAHL, PsycINFO, PsychARTICLES and Health and Psychosocial Instruments for articles published up to January 2015 for studies including people diagnosed with AMD, assessing real-world visual ability or QoL as an outcome. Two researchers screened studies for eligibility. Details of eligible studies including study design, characteristics of study population and outcomes measured were recorded in a data extraction table. All included studies underwent quality appraisal using the Mixed Methods Appraisal Tool 2011 Version (MMAT).
Results
From 5284 studies, 123 were eligible for inclusion. A range of approaches were identified, including performance-based methods, quantitative and qualitative patient-reported outcome measures (PROMs). AMD negatively affects tasks including mobility, face recognition, perception of scenes, computer use, meal preparation, shopping, cleaning, watching TV, reading, driving and, in some cases, self-care. There is evidence for higher rates of depression among people with AMD than among community dwelling elderly. A number of adaptation strategies have been associated with AMD of varying duration. Much of the research fails to report the type of AMD studied (59% of included studies) or the duration of disease in participants (74%). Of those that do report type studied, the breakdown is as follows: wet AMD 20%, dry AMD 4% and both types 17%.
Conclusions
There are many publications highlighting the negative effects of AMD in various domains of life. Future research should focus on delivering some of this research knowledge into patient management and clinical trials and differentiating between the types of AMD
Venus - Preliminary science objectives and experiments for use in advanced mission studies
Mission planning and experiment design for future Mariner-type Venus space probe
Live to cheat another day: bacterial dormancy facilitates the social exploitation of beta-lactamases
The breakdown of antibiotics by β-lactamases may be cooperative, since resistant cells can detoxify their environment and facilitate the growth of susceptible neighbours. However, previous studies of this phenomenon have used artificial bacterial vectors or engineered bacteria to increase the secretion of β-lactamases from cells. Here, we investigated whether a broad-spectrum β-lactamase gene carried by a naturally occurring plasmid (pCT) is cooperative under a range of conditions. In ordinary batch culture on solid media, there was little or no evidence that resistant bacteria could protect susceptible cells from ampicillin, although resistant colonies could locally detoxify this growth medium. However, when susceptible cells were inoculated at high densities, late-appearing phenotypically susceptible bacteria grew in the vicinity of resistant colonies. We infer that persisters, cells that have survived antibiotics by undergoing a period of dormancy, founded these satellite colonies. The number of persister colonies was positively correlated with the density of resistant colonies and increased as antibiotic concentrations decreased. We argue that detoxification can be cooperative under a limited range of conditions: if the toxins are bacteriostatic rather than bacteridical; or if susceptible cells invade communities after resistant bacteria; or if dormancy allows susceptible cells to avoid bactericides. Resistance and tolerance were previously thought to be independent solutions for surviving antibiotics. Here, we show that these are interacting strategies: the presence of bacteria adopting one solution can have substantial effects on the fitness of their neighbours
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Effect of varying skin surface electrode position on electroretinogram responses recorded using a handheld stimulating and recording system
Purpose
A handheld device (the RETeval system, LKC Technologies) aims to increase the ease of electroretinogram (ERG) recording by using specially designed skin electrodes, rather than corneal electrodes. We explored effects of electrode position on response parameters recorded using this device.
Methods
Healthy adult twins were recruited from the TwinsUK cohort and underwent recording of light-adapted flicker ERGs (corresponding to international standard stimuli). In Group 1, skin electrodes were placed in a “comfortable” position, which was up to 20 mm below the lid margin. For subsequent participants (Group 2), the electrode was positioned 2 mm from the lid margin as recommended by the manufacturer. Amplitudes and peak times (averaged from both eyes) were compared between groups after age-matching and inclusion of only one twin per pair. Light-adapted flicker and flash ERGs were recorded for an additional 10 healthy subjects in two consecutive recording sessions: in the test eye, electrode position was varied from 2 to 10–20 mm below the lid margin between sessions; in the fellow (control) eye, the electrode was 2 mm below the lid margin throughout. Amplitudes and peak times (test eye normalised to control eye) were compared for the two sessions.
Results
Including one twin per pair, and age-matching yielded 28 individuals per group. Flicker ERG amplitudes were significantly lower for Group 1 than Group 2 participants (p = 0.0024). However, mean peak times did not differ between groups (p = 0.54). For the subjects in whom electrode position was changed between recording sessions, flash and flicker amplitudes were significantly lower when positioned further from the lid margin (p 0.5).
Conclusions
Moving the skin electrodes further from the lid margin significantly reduces response amplitudes, highlighting the importance of consistent electrode positioning. However, this does not significantly affect peak times. Thus, it may be feasible to adopt a more comfortable position in participants who cannot tolerate the recommended position if analysis is restricted to peak time parameters
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