Backwards State-space Reduction for Planning in Dynamic Knowledge Bases

In this paper we address the problem of planning in rich domains, where knowledge representation is a key aspect for managing the complexity and size of the planning domain. We follow the approach of Description Logic (DL) based Dynamic Knowledge Bases, where a state of the world is represented concisely by a (possibly changing) ABox and a (fixed) TBox containing the axioms, and actions that allow to change the content of the ABox. The plan goal is given in terms of satisfaction of a DL query. In this paper we start from a traditional forward planning algorithm and we propose a much more efficient variant by combining backward and forward search. In particular, we propose a Backward State-space Reduction technique that consists in two phases: first, an Abstract Planning Graph P is created by using the Abstract Backward Planning Algorithm (ABP), then the abstract planning graph P is instantiated into a corresponding planning graph P by using the Forward Plan Instantiation Algorithm (FPI). The advantage is that in the preliminary ABP phase we produce a symbolic plan that is a pattern to direct the search of the concrete plan. This can be seen as a kind of informed search where the preliminary backward phase is useful to discover properties of the state-space that can be used to direct the subsequent forward phase. We evaluate the effectiveness of our ABP+FPI algorithm in the reduction of the explored planning domain by comparing it to a standard forward planning algorithm and applying both of them to a concrete business case study.Comment: In Proceedings GRAPHITE 2014, arXiv:1407.767

Stochastically timed predicate-based communication primitives for autonomic computing

Predicate-based communication allows components of a system to send messages and requests to ensembles of components that are determined at execution time through the evaluation of a predicate, in a multicast fashion. Predicate-based communication can greatly simplify the programming of autonomous and adaptive systems. We present a stochastically timed extension of the Software Component Ensemble Language (SCEL) that was introduced in previous work. Such an extension raises a number of non-trivial design and formal semantics issues with different options as possible solutions at different levels of abstraction. We discuss four of these options. We provide formal semantics and an illustration of the use of the language modeling a variant of a bike sharing system, together with some preliminary analysis of the system performance

Coronavirus Disease 2019: Where are we and Where are we Going? Intersections Between Coronavirus Disease 2019 and the Heart

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19), which has become a pandemic affecting every country in the world. In the province of Bergamo, Italy, more than 2,200 cases of COVID-19 have been reported, which include more than 300 deaths. Most hospitalisations have been at the Papa Giovanni XXIII Hospital. This has imposed a significant burden on our hospital in terms of healthcare personnel, dedicated spaces (including intensive care areas) and time spent by clinicians, who are committed to assisting COVID-19 patients. In this short expert opinion, the authors will focus on new insights related to COVID-19 and the cardiovascular system, and try to investigate the grey areas and uncertainties in this field

A formalized framework for mobile cloud computing

Mobile Cloud Computing (MCC) is an emerging paradigm to transparently provide support for demanding tasks on resource-constrained mobile devices by relying on the integration with remote cloud services. Research in this field is tackling the multiple conceptual and technical challenges (e.g., how and when to offload) that are hindering the full realization of MCC. The Networked Autonomic Machine (NAM) framework is a tool that supports and facilitates the design networks of hardware and software autonomic entities, providing or consuming services or resources. Such a framework can be applied, in particular, to MCC scenarios. In this paper, we focus on NAM’s features related to the key aspects of MCC, in particular those concerning code mobility capabilities and autonomic offloading strategies. Our first contribution is the definition of a set of high-level actions supporting MCC. The second contribution is the proposal of a formal semantics for those actions, which provides the core NAM features with a precise formal characterization. Thus, the third contribution is the further development of the NAM conceptual framework and, in particular, the partial re-engineering of the related Java middleware. We show the effectiveness of the revised middleware by discussing the implementation of a Global Ambient Intelligence case study

Sodium–Glucose Cotransporter 2 Inhibitors in Heart Failure with Preserved Ejection Fraction: Rationale for and Practical Use of a Successful Therapy

Heart failure (HF) with preserved left ventricular ejection fraction is a common disease with a poor prognosis and rising prevalence in the community. The current paradigm of treatment includes symptomatic therapy, such as diuretics, and risk factor control and treatment of comorbidities. According to European guidelines, there is no effective therapy for patients with HF with left ventricular ejection fraction (LVEF) ≥50%, while drugs normally used in HF with reduced LVEF might also be effective for patients with mildly reduced LVEF (40–50%), with a IIB class of recommendation. The recently published EMPEROR-Preserved trial has challenged current guidelines, demonstrating improved outcomes in patients with HF and LVEF >40% with the sodium–glucose cotransporter 2 inhibitor (SGLT2I) empagliflozin, compared with placebo. This result was consistent in patients with and without diabetes as well as in those with LVEF below and above 50%. The authors describe the rationale for this therapy, presenting the main results of the EMPEROR-Preserved trial, and provide some recommendations for the everyday clinical management of HF with preserved left ventricular ejection with an SGLT2I

Thirty years of evidence on the efficacy of drug treatments for chronic heart failure with reduced ejection fraction: A network meta-analysis

Treatments that reduce mortality and morbidity in patients with heart failure with reduced ejection fraction, including angiotensin-converting enzyme inhibitors (ACEI), angiotensin receptor blockers (ARB), β-blockers (BB), mineralocorticoid receptor antagonists (MRA), and angiotensin receptor–neprilysin inhibitors (ARNI), have not been studied in a head-to-head fashion. This network meta-analysis aimed to compare the efficacy of these drugs and their combinations regarding all-cause mortality in patients with heart failure with reduced ejection fraction

Implantation of an Elastic Ring at Equator of the Left Ventricle Influences Cardiac Mechanics in Experimental Acute Ventricular Dysfunction

ObjectivesWe hypothesize that the implantation of an endoventricular elastic ring at the left ventricle (LV) equatorial site will positively affect the cardiac mechanics in an experimental model of acute LV dysfunction.BackgroundChanges in the elastic properties of LV occur in the dilated and failing heart, contributing to overall cardiac mechanical dysfunction. No interventions are as yet specifically designed to improve LV elasticity in failing hearts.MethodsAcute LV enlargement and dysfunction was induced in 13 healthy sheep via the insertion of a large Dacron patch into the lateral wall. In 6 of these sheep, a customized elastic ring was implanted at the inner surface of the LV equator (ring group), and the remaining 7 served as control subjects (dysfunction group). Systolic and diastolic function was evaluated using echocardiography and pressure–volume (P–V) analysis.ResultsIn the ring group, both the maximum rate of pressure increase and the slope of end-systolic P–V relationship were significantly different from those without ring (1,718 ± 726 vs. 1,049 ± 269 and 1.25 ± 0.30 vs. 0.88 ± 0.19; both p < 0.05). Preload recruitable stroke work changed even more prominently (33 ± 11 vs. 17 ± 5; p = 0.005), along with stroke volume, ejection fraction, and stroke work. Although ring implantation had no effect on end-diastolic P–V relationship, it positively affected the active component of diastole: the maximum rate of pressure decrease declined significantly (p = 0.037). The time constant of relaxation tended to decrease (37 ± 8 vs. 44 ± 6; p = 0.088).ConclusionsImproving the elastic component of the LV at its equatorial site substantially augments contractility and early relaxation in acute systodiastolic LV dysfunction

Use of echocardiography in the management of congestive heart failure in the community

AbstractObjectives. We evaluated the use and the impact of echocardiography in patients receiving an initial diagnosis of congestive heart failure in Olmsted County, Minnesota, in 1991.Background. The American College of Cardiology/American Heart Association clinical practice guidelines recommend echocardiography in all patients with suspected congestive heart failure. No data are available on use and impact of echocardiography in management of congestive heart failure in a community.Methods. The medical records linkage system of the Rochester Epidemiology Project was used to identify all 216 patients who satisfied the Framingham criteria for congestive heart failure. Of these, 137 (63%) underwent echocardiography within 3 weeks before or after the episode of congestive heart failure (Echo group), and the other 79 patients constitute the No-Echo group.Results. The No-Echo group patients were older (p = 0.022), were more likely to be female (p = 0.072), had milder symptoms (p = 0.001) and were less often hospitalized at diagnosis (p = 0.001). Fewer patients in the No-Echo group were treated with angiotensin-converting enzyme inhibitors (p = 0.001). Advanced age (≥80 years), lower New York Heart Association functional class, absence of a fourth heart sound on examination, absence of cardiomegaly or signs of congestive heart failure on chest radiography and absence of known valve disease were independently related to the decision not to obtain an echocardiogram. Survival after adjustment for age, functional class and gender was lower in the No-Echo group than the Echo group (risk ratio = 0.607, p = 0.017).Conclusions. The underuse of echocardiography appears to be associated with poorer survival and underuse of angiotensin-converting enzyme inhibitor therapy

Should we increase betablocker after cardiac resynchronization therapy: the results of the caribe-hf study (cardiac resynchronization in combination with betablocker treatment in advanced chronic heart failure)

Cardiac resynchronization therapy (CRT), combined with optimal medical therapy (OMT), is an established treatment for patients with advanced chronic heart failure (ACHF). In ACHF, carvedilol at the dose used in clinical trials reduces morbidity and mortality. However, patients often cannot tolerate the drug at the targeted dosage. Aim of the CARIBE-HF prospective observational study was to investigate the role of CRT in the implementation of carvedilol therapy in patients with ACHF. Methods: One hundred and 6 patients (aged 65±12 [mean±sd] years) with ACHF were enrolled and treated with OMT, in which carvedilol was titrated up to the maximal dose (phase 1). Subsequently, patients with left ventricular (LV) ejection fraction < 35%, NYHA class III-IV and QRS interval ≥ 120 msec were assigned to CRT. Both CRT and NO-CRT patients underwent long-term follow-up till 7 years (1193,98±924 days), while efforts to up-titrate the carvedilol dose were continued during the second phase (471±310 days). Phase 1 was completed by 84 patients (79%), and 15 (18%) underwent CRT. The mean carvedilol dose in the CRT group was 19.0±17.8 mg, against 32.7±19.1 mg in the remaining 69 patients (p=0.018). At the end of phase 2, CRT patients presented a significantly greater variation of increasing in the carvedilol dose than NO-CRT patients ( 20.0±19.8 mg vs –0.3±20.5 mg; p=0.015), a greater NYHA class reduction (-0.8±0.6 vs -0.2±0.7; p=0.011), and a greater increase in LV ejection fraction ( 10.8±9 vs 3.1±6.1; p=0.018). In conclusion, the data from the CARIBE study suggest that, in ACHF, CRT may be effective in enabling the target dose of carvedilol to be reached. The significant improvement seen in LV function was probably due to a synergistic effect of CRT and carvedilol. During the extended follow-up (mean 1193,98±924 days) the mean dosage of carvedilol in CRT group was significantly higher (