135 research outputs found
LTSmin: high-performance language-independent model checking
In recent years, the LTSmin model checker has been extended with support for several new modelling languages, including probabilistic (Mapa) and timed systems (Uppaal). Also, connecting additional language front-ends or ad-hoc state-space generators to LTSmin was simplified using custom C-code. From symbolic and distributed reachability analysis and minimisation, LTSmin’s functionality has developed into a model checker with multi-core algorithms for on-the-fly LTL checking with partial-order reduction, and multi-core symbolic checking for the modal μ calculus, based on the multi-core decision diagram package Sylvan.\ud
In LTSmin, the modelling languages and the model checking algorithms are connected through a Partitioned Next-State Interface (Pins), that allows to abstract away from language details in the implementation of the analysis algorithms and on-the-fly optimisations. In the current paper, we present an overview of the toolset and its recent changes, and we demonstrate its performance and versatility in two case studies
Simulation of organ patterning on the floral meristem using a polar auxin transport model
An intriguing phenomenon in plant development is the timing and positioning of lateral organ initiation,
which is a fundamental aspect of plant architecture. Although important progress has been made in
elucidating the role of auxin transport in the vegetative shoot to explain the phyllotaxis of leaf formation
in a spiral fashion, a model that explains the whorled organ patterning in the expanding floral meristem
is not available yet. We present an initial simulation approach to study the mechanisms that are expected
to play an important role. Starting point is a confocal imaging study of Arabidopsis floral meristems
at consecutive time points during flower development. These images reveal auxin accumulation patterns
at the positions of the organs, which strongly suggests that the role of auxin in the floral meristem is
similar to the role it plays in the shoot apical meristem. This is the basis for a simulation study of auxin
transport through a growing floral meristem, which may answer the question whether auxin transport can
in itself be responsible for the typical whorled floral pattern. We combined a cellular growth model for
the meristem with a polar auxin transport model. The model predicts that sepals are initiated by auxin maxima arising early during meristem outgrowth. These form a pre-pattern relative to which a series of
smaller auxin maxima are positioned, which partially overlap with the anlagen of petals, stamens, and
carpels. We adjusted the model parameters corresponding to properties of floral mutants and found that
the model predictions agree with the observed mutant patterns. The predicted timing of the primordia
outgrowth and the timing and positioning of the sepal primordia show remarkable similarities with a
developing flower in nature
Role of metformin in diabetes treatment--is metformin falling from grace?
Two recent meta-analyses focused on the risk-benefit ratio of metformin in the treatment of type 2 diabetes mellitus. Both studies conclude that the risk-benefit ratio of metformin monotherapy or combined with insulin is uncertain. In our opinion, the interpretation of the known literature in these meta-analyses could be flawed. To ascertain the effects of metformin on cardiovascular end-points, a follow-up period of at least 8 years proved necessary. However, these meta-analyses included a number of studies with a limited follow-up period, thus impairing the possibility to make a proper comparison of the long-term effects of metformin. In addition, one meta-analysis based the weight of included studies on the number of events in all studies, including two safety studies, as opposed to the number of studied patients.</p
The Involvement of Service Users and People With Lived Experience in Mental Health Care Innovation Through Design: Systematic Review
Background: Mental health care faces challenges that not only necessitate innovation but also require the involvement of service users and people with lived experience in developing and evaluating mental health care services. As the development of digital interventions is becoming more prevalent, design approaches are increasingly finding their way into mental health. There is evidence that these approaches can successfully integrate user experience into mental health services. However, there is no clear overview of the studies conducted and the lessons learned concerning the involvement of service users and people with lived experience. Objective: In this systematic review, we aimed to provide an overview of the involvement of service users and people with lived experience in mental health care services through design approaches and to synthesize the advantages of design approaches in mental health care. Methods: The following 5 databases were searched for relevant abstracts: PsycINFO, PubMed, Web of Science, Scopus, and Embase. In addition, 2 health design journal archives, Design for Health and The Journal of Health Design, were searched. To categorize the results, we collected the reported added value from the included articles and conducted a thematic synthesis in which the themes were developed from the retrieved data. The themes were discussed, revised, and checked until saturation was achieved. Results: We included and categorized 33 papers. Most studies involved service users, primarily adults, and used various design approaches. Most of these studies aimed to design or evaluate digital interventions. Service users and people with lived experience were involved in different roles but never as decision makers. Studies that used co-design approaches exhibited the highest levels of involvement. Various added values were reported, including tailoring and testing interventions and digital interventions, improving engagement and collaboration, gathering the needs of stakeholders, and empowering participants as resourceful actors. The challenges reported were maintaining participants' continued participation throughout the study, managing the iterative nature of design, providing a safe space, balancing insights from design and medical science, and navigating design processes in medical environments. Conclusions: This systematic review provides an overview of the studies that used design approaches to involve service users and people with lived experience in mental health care innovation. Design approaches have advantages in mental health care innovation, offering added value and having manageable challenges. Future studies using design approaches in mental health care should involve participants as partners and decision makers and report on collaboration in a systematic and clear manner
Salinity-induced increase of the hydraulic conductivity in the hyporheic zone of coastal wetlands
In coastal zones globally, salinization is rapidly taking place due to the combined effects of sea level rise, land subsidence, altered hydrology, and climate change. Although increased salinity levels are known to have a great impact on both biogeochemical and hydrological processes in aquatic sediments, only few studies have included both types of processes and their potential interactions. In the present paper, we used a controlled 3-year experimental mesocosm approach to test salinity induced interactions and discuss mechanisms explaining the observed hydrological changes. Surface water salinity was experimentally increased from 14 to 140 mmol Cl per L (0.9 and 9 PSU) by adding sea salt which increased pore water salinity but also increased sulfate reduction rates, leading to higher sulfide, and lower methane concentrations. By analyzing slug test data with different slug test analysis methods, we were able to show that hydraulic conductivity of the hyporheic zone increased 2.8 times by salinization. Based on our hydrological and biogeochemical measurements, we conclude that the combination of pore dilation and decreased methane production rates were major controls on the observed increase in hydraulic conductivity. The slug test analysis method comparison allowed to conclude that the adjusted Bouwer and Rice method results in the most reliable estimate of the hydraulic conductivity for hyporheic zones. Our work shows that both physical and biogeochemical processes are vital to explain and predict hydrological changes related to the salinization of hyporheic zones in coastal wetlands and provides a robust methodological approach for doing so
Hogere zoutconcentratie leidt tot een verhoogde waterdoorlatendheid van de waterbodem
Door de combinatie van klimaatverandering (zeespiegelstijging en langere droogteperiodes) en ontwatering voor landbouw neemt de kans op stijgende zoutconcentratiesin het oppervlaktewater in laag Nederland toe. Hoewel bekend is dat dit chemische enfysische effecten kan hebben, is de interactie tussen fysische en biogeochemische processen onderbelicht gebleven. In dit artikel wordt een veldexperiment gepresenteerdwaarin de effecten van verhoogde zoutconcentraties op de combinatie van chemischeen fysische processen in een voormalig brak laagveen zijn bestudeerd. Met behulp vanbiogeochemische analyses en de omgekeerde boorgatmethode in de waterbodem wordtaangetoond dat een verhoogde zoutconcentratie in het oppervlaktewater kan leiden toteen verhoogde waterdoorlatendheid van de waterbodem
Factors influencing submerged macrophyte presence in fresh and brackish eutrophic waters and their impact on carbon emissions
In agricultural landscapes of North-Western Europe, the majority of water bodies do not meet the targets set by the European Water Framework Directive due to a lack of submerged macrophytes and associated biodiversity. These eutrophic waters can also be a substantial source of methane (CH4) and carbon dioxide (CO2) to the atmosphere. Here we present a two-year field experiment on the island of Goeree-Overflakkee (southwest Netherlands), conducted in six drainage ditches varying in salinity, where we monitored four permanent plots per ditch and varied the presence of both fish and macrophytes. We aimed to: 1) investigate factors limiting submerged macrophyte growth, focussing on exclusion of grazing pressure and bioturbation by fish; and 2) quantify the CO2 and CH4 emission under these conditions. Even in highly eutrophic, semi turbid ditches with fluctuating salinity levels and sulphide presence in the root zone, submerged macrophytes established successfully after introduction when the influence of grazing and bioturbation by fish was excluded. In the exclosures, diffusive CH4 and CO2 emissions, but not ebullitive CH4 emissions were significantly reduced. The spontaneous development of submerged macrophytes in the exclosures without macrophyte introduction underlined the effect of grazing and bioturbation by fish and suggest that abiotic conditions did not hamper submerged macrophyte development. Our results provide important insights into the influential factors for submerged macrophyte development and potential for future management practices. Large-scale fish removal may stimulate submerged macrophyte growth and reduce methane emissions, albeit that the macrophyte diversity will likely stay low in our study region due to fluctuating salinity and eutrophic conditions.</p
- …