Drought versus heat: What's the major constraint on Mediterranean green roof plants?

Green roofs are gaining momentum in the arid and semi-arid regions due to their multiple benefits as compared with conventional roofs. One of the most critical steps in green roof installation is the selection of drought and heat tolerant species that can thrive under extreme microclimate conditions. We monitored the water status, growth and survival of 11 drought-adapted shrub species grown on shallow green roof modules (10 and 13cm deep substrate) and analyzed traits enabling plants to cope with drought (symplastic and apoplastic resistance) and heat stress (root membrane stability). The physiological traits conferring efficiency/safety to the water transport system under severe drought influenced plant water status and represent good predictors of both plant water use and growth rates over green roofs. Moreover, our data suggest that high substrate temperature represents a stress factor affecting plant survival to a larger extent than drought per se. In fact, the major cause influencing seedling survival on shallow substrates was the species-specific root resistance to heat, a single and easy measurable trait that should be integrated into the methodological framework for screening and selection of suitable shrub species for roof greening in the Mediterranean

Contextualisation of information in digital twin processes

Digital twins are required to process a large amount of data during operation, in order to achieve specific tasks, over the lifetime of the physical twin that they relate to. One important feature of processing data is the identification of trust in both the underlying data and processed information that arises from the data. Trust, as it is defined here, will typically be built from several contributory sources. While there are both quantitative and qualitative sources of trust, this paper focuses on the qualitative aspects of trust via the transparency of the algorithmic process that is available in the crystal-box modelling. The crystal-box idea is also extended to include the concept of a ‘crystal-box workflow’. The key idea is that in order to assist the user of the digital twin to interpret the results they are presented with, via the digital twin interface, the information needs to be contextualised. This work shows an example of how this can be done for a vibration testing (specifically modal testing) example on a scaled three-storey structure. The information is contextualised for the user via ‘profiles’, which collate and augment the processed information together. In particular, synthetic results are generated in order to augment a limited set of physically recorded data, and these synthetic results are then used to assist the user in contextualising the physically recorded data. Implementation results are shown using an open-source digital twin code called DTOP-Cristallo

Development of a digital twin operational platform using Python Flask

The digital twin concept has developed as a method for extracting value from data, and is being developed as a new technique for the design and asset management of high-value engineering systems such as aircraft, energy generating plant, and wind turbines. In terms of implementation, many proprietary digital twin software solutions have been marketed in this domain. In contrast, this paper describes a recently released open-source software framework for digital twins, which provides a browser-based operational platform using Python and Flask. The new platform is intended to maximize connectivity between users and data obtained from the physical twin. This paper describes how this type of digital twin operational platform (DTOP) can be used to connect the physical twin and other Internet-of-Things devices to both users and cloud computing services. The current release of the software—DTOP-Cristallo—uses the example of a three-storey structure as the engineering asset to be managed. Within DTOP-Cristallo, specific engineering software tools have been developed for use in the digital twin, and these are used to demonstrate the concept. At this stage, the framework presented is a prototype. However, the potential for open-source digital twin software using network connectivity is a very large area for future research and development

Clinical features and outcomes of elderly hospitalised patients with chronic obstructive pulmonary disease, heart failure or both

Background and objective: Chronic obstructive pulmonary disease (COPD) and heart failure (HF) mutually increase the risk of being present in the same patient, especially if older. Whether or not this coexistence may be associated with a worse prognosis is debated. Therefore, employing data derived from the REPOSI register, we evaluated the clinical features and outcomes in a population of elderly patients admitted to internal medicine wards and having COPD, HF or COPD + HF. Methods: We measured socio-demographic and anthropometric characteristics, severity and prevalence of comorbidities, clinical and laboratory features during hospitalization, mood disorders, functional independence, drug prescriptions and discharge destination. The primary study outcome was the risk of death. Results: We considered 2,343 elderly hospitalized patients (median age 81 years), of whom 1,154 (49%) had COPD, 813 (35%) HF, and 376 (16%) COPD + HF. Patients with COPD + HF had different characteristics than those with COPD or HF, such as a higher prevalence of previous hospitalizations, comorbidities (especially chronic kidney disease), higher respiratory rate at admission and number of prescribed drugs. Patients with COPD + HF (hazard ratio HR 1.74, 95% confidence intervals CI 1.16-2.61) and patients with dementia (HR 1.75, 95% CI 1.06-2.90) had a higher risk of death at one year. The Kaplan-Meier curves showed a higher mortality risk in the group of patients with COPD + HF for all causes (p = 0.010), respiratory causes (p = 0.006), cardiovascular causes (p = 0.046) and respiratory plus cardiovascular causes (p = 0.009). Conclusion: In this real-life cohort of hospitalized elderly patients, the coexistence of COPD and HF significantly worsened prognosis at one year. This finding may help to better define the care needs of this population

G6PD deficiency in Latin America: systematic review on prevalence and variants

Plasmodium vivax radical cure requires the use of primaquine (PQ), a drug that induces haemolysis in glucose-6-phosphate dehydrogenase deficient (G6PDd) individuals, which further hampers malaria control efforts. The aim of this work was to study the G6PDd prevalence and variants in Latin America (LA) and the Caribbean region. A systematic search of the published literature was undertaken in August 2013. Bibliographies of manuscripts were also searched and additional references were identified. Low prevalence rates of G6PDd were documented in Argentina, Bolivia, Mexico, Peru and Uruguay, but studies from Curaçao, Ecuador, Jamaica, Saint Lucia, Suriname and Trinidad, as well as some surveys carried out in areas of Brazil, Colombia and Cuba, have shown a high prevalence (> 10%) of G6PDd. The G6PD A-202A mutation was the variant most broadly distributed across LA and was identified in 81.1% of the deficient individuals surveyed. G6PDd is a frequent phenomenon in LA, although certain Amerindian populations may not be affected, suggesting that PQ could be safely used in these specific populations. Population-wide use of PQ as part of malaria elimination strategies in LA cannot be supported unless a rapid, accurate and field-deployable G6PDd diagnostic test is made available

Experimental implementation of a nonlinear feedback controller for a stroke limited inertial actuator

This research consists of theoretical and experimental studies of a stroke limited inertial, or proof mass, actuator used in active vibration control. Traditionally, inertial actuators are used with velocity feedback controllers to reduce structural vibrations. However, physical limits, such as stroke saturation, can affect the behaviour and the stability of the control system. In fact, stroke saturation results in impulse like excitations, which are transmitted to the structure that is liable to damage. Moreover, the shocks produced by the impacts are in phase with the velocity of the structure. This produces an input force, which reduces the overall damping and eventually leads to limit cycle oscillations and the instability of the system. This paper examines the experimental implementation of a nonlinear feedback controller to avoid collisions of the proof mass with the actuator’s end stops, hence preventing the instability of the system due to stroke saturation. Firstly, the nonlinear behaviour of the stroke limited inertial actuator is reported. This allows identifying the stroke length of the proof mass. Secondly, the nonlinear feedback controller is presented, which acts as a second loop alongside the velocity feedback control loop. The main purpose of the nonlinear feedback controller is to increase the damping of the actuator when the poof mass gets close to the end stops. Finally, the experimental implementation of the nonlinear controller is investigated and a comparison in terms of performance and stability of the control system is made when both the feedback loops or only the velocity feedback loop are present.</p