579 research outputs found
Data-Driven Building Energy Modelling – Generalisation Potential of Energy Signatures Through Interpretable Machine Learning
No full textBuilding energy modeling based on data-driven techniques has been demonstrated to be effective in a variety of situations. However, the question about its limits in terms of generalization is still open. The ability of a machine-learning model to adapt to previously unseen data and function satisfactorily is known as generalization. Apart from that, while machine-learning techniques are incredibly effective, interpretability is required for a "human-in-the-loop" approach to be successful. This study develops and tests a flexible regression-based approach applied to monitored energy data on a Passive House building. The formulation employs dummy (binary) variables as a piecewise linearization method, with the procedures for producing them explicitly stated to ensure interpretability. The results are described using statistical indicators and a graphic technique that allows for comparison across levels in the building systems. Finally, suggestions are provided for further steps toward generalization in data-driven techniques for energy in buildings
Management of the Proximal Anastomosis in Open, Hybrid Repair of Thoracoabdominal Aortic Aneurysm (Reply)
No full textA Comparison of Thermal Insulation with Interstitial Condensation in Different Climate Contexts in Existing Buildings in Europe
No full textThe work presented here investigates the risk of interstitial condensation between the existing masonry and the insulation using several materials and evaluates the water content inside the insulation (WCI) through various simulations in dynamic mode onto existing buildings located in different countries in Europe. The insulation materials considered are specifically: natural fibre materials, mineral fibre materials, and artificial materials. The scenarios were chosen considering different climate zones, according to the Köppen climate classification, and the analysed buildings were taken from the TABULA database in the years of construction from 1945 to 1969. The building typologies are single-family houses, where in each building system the insulation was placed towards the warm side with a fixed thickness of 5 cm. The simulations concerned: (a) the application scenario, (b) the type of stratigraphy chosen, and (c) the exposure of the existing building system. The outputs generated by the simulations provided the data to determine in which type of building, depending on the insulating materials, interstitial condensation is formed or not. It is shown that only for the climate zones of the cities of Oslo and Brussels, associated with their building typologies, for the insulating materials: mineral and natural, is there the formation of interstitial condensatio
Parametric simulations to evaluate occupants' behavior incidence on building energy performance - a Passive House case study
No full textThe building industry's rising commitment to resource efficiency is influencing the evolution of building design and operation practices. At the same time, built environment decarbonisation is among the most important policy goals at the EU and global scale. High performance building design are emerging and their deployment in practice involves both new and existing buildings. Taking advantage of heat gains (solar and internal) to balance heat losses, as in passive design strategies, is becoming more increasingly relevant, but this must be carefully considered to reduce the risk of overheating during intermediate seasons and an increase of cooling demand during summer. In general, however, optimistic assumptions are frequently made during the design phase; semi-stationary calculation methods also are still widely used, especially for code compliance. Furthermore, the impact on performance of occupant's behaviour and comfort preferences is frequently overlooked. This study investigates the potential variability of simulated performance in a case study building constructed in Italy to the Passive House standard. The study contrasts the initial design hypothesis, which was developed using a semi-stationary model, to a larger set of data created through parametric simulations using a Design of Experiments methodology and a grey-box dynamic model. The modelling approach presented aims to detect potentially problematic assumptions early in the design process, with minimal computational effort. A detailed examination of design solutions from the early design stage can aid in the provision of more robust energy performance assessments, resulting in positive implications for techno-economic optimisation and for the credibility of high performance building design paradigms. </p
Peri-operative prophylaxis with phenytoin: dosage and therapeutic plasma levels
No full textEarly postoperative epilepsy is a frequent complication of supratentorial intracranial surgery. The lack of consensus on prophylaxis of early postoperative seizures with phenytoin (PHT) may be due to the different dosages used in several studies, owing to inadequate therapeutic plasma level. The aim of this study was to evaluate which dosage of PHT can maintain the therapeutic range in the early postoperative period. Twenty patients operated on for supratentorial neoplasms were randomly allocated to receive, during the last hour of the surgical procedure, loading doses of either 10 mg/kg (group A, n = 10) or 15 mg/kg (group B, n = 10) of PHT. PHT infusion rate never exceeded 30 mg/min. Six hours after the loading dose, PHT maintenance treatment (250 mg, i.v., every 8 hours) was started in all patients. PHT plasma levels were evaluated from the end of the intra-operative loading infusion up to 24 h. During the first six hours after the loading dose, phenytoin plasma levels fell below the therapeutic range (10-20 mg/l) in 7 out of the 10 patients receiving 10 mg/kg, while in the patients treated with 15 mg/kg, PHT plasma levels were always in the therapeutic range (P < or = 0.0001). PHT maintenance dose was sufficient to keep plasma levels within the therapeutic range in 8 patients in group A, and in all the patients in group B. It is concluded that a loading dose of 15 mg/kg, followed by postoperative treatment, is necessary to guarantee therapeutic plasma levels of phenytoin in the immediate postoperative period, when seizure risk is very high
Local cerebral blood flow during lidocaine-induced seizures in rats
No full textNeurophysiologic and local cerebral metabolic mapping techniques indicate that seizures associated with lidocaine toxicity originate in subcortical brain structures. Normally local cerebral blood flow (l-CBF) is quantitatively coupled to local cerebral metabolic rate for glucose (l-CMR(g)). In the present study the response of l-CBF to a lidocaine-induced preconvulsive state (localized seizure activity in the absence of a grand mal seizure) was evaluated in rats anesthetized with 60% nitrous oxide. Lidocaine administered as a bolus (20 mg/kg) followed by an infusion (4 mg/kg) over 5.5 min resulted in progressive alteration in the electroencephalogram (EEG). L-CBF was studied with the 14 C-iodoantypyrine autographic method when the preconvulsive EEG pattern consisted of a repetitive spike and wave complex at a frequency of 14 ± 1·min -1 complexes, superimposed on practically isoelectric background activity. Under these conditions high doses of lidocaine significantly (P < 0.05) decreased (range -30% to -68%) l-CBF in 71% of the 34 brain regions studied. The greatest exception to this trend for l-CBF to decrease was observed in the limbic system wherein l-CBF remained within control ranges in eight of the 11 structures evaluated. Qualitative comparison of lidocaine l-CBF changes with l-CMR(g) changes obtained under similar conditions indicated a general trend for local flow and metabolism to decrease in parallel. Exceptions to this were confined to certain limbic areas (amygdala and hippocampus) in which increases in l-CMR(g) were more than 100% greater than slight (P > 0.05) increases in l-CBF. This comparison demonstrates uncoupling of local brain metabolism from blood flow during lidocaine-induced subcortical epileptoid discharges (preconvulsive state) in areas recognized to be prone to irreversible damage when seizure activity is much prolonged beyond the duration of this study
Emergency fast Bentall operation
No full textWe herein report an emergency technique of composite Bentall operation using a fast release valve. The technique was successfully performed in 2 emergency cases after failed supracoronary ascending aortic replacement in acute Type A aortic dissection. The speed and ease of execution are the main advantages of the procedure
Il monitoraggio del paziente pediatrico in corso di risonanza magnetica con un magnete superconduttore
No full textMagnetic resonance imaging (MRI) has presented to anesthesiologists as unique challenge in patient monitoring because of its construction and principles of operation. Ferromagnetic materials within or near the scanner can distort the magnetic field, and monitoring wires act as antennae and this may result in image degradation. Nevertheless, monitoring is mandatory during MRI, especially in a child sedated or in general anesthesia. A monitoring system, made up of commercially available components, was assessed, and its effects on MR (1.5 tesla unit) image quality system determined. Variables monitored included: electrocardiogram and heart rate, (Sirecust 404, ECG cable set MR; Siemens, Enlanger, West Germany); blood pressure via automated sphygmomanometry (Press Mate BP-8800; Colin, Komaki, Japan); and continuous arterial saturation via pulse oximetry (Nellcor 100 E; Nellcor, Inc., Haywood, California). Fluid infusion rate was controlled by means of a plastic deliver (Dial-a-flo; Abbott Labs., Chicago, Illinois). Body temperature was maintained with a heat insulator blanket (Thermadrape, OR Concepts, Inc., Dallas, Texas). The monitoring technique described did not interfere with MRI function or produce image degradation
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