A decidable subclass of finitary programs

Answer set programming - the most popular problem solving paradigm based on logic programs - has been recently extended to support uninterpreted function symbols. All of these approaches have some limitation. In this paper we propose a class of programs called FP2 that enjoys a different trade-off between expressiveness and complexity. FP2 programs enjoy the following unique combination of properties: (i) the ability of expressing predicates with infinite extensions; (ii) full support for predicates with arbitrary arity; (iii) decidability of FP2 membership checking; (iv) decidability of skeptical and credulous stable model reasoning for call-safe queries. Odd cycles are supported by composing FP2 programs with argument restricted programs

On finitely recursive programs

Disjunctive finitary programs are a class of logic programs admitting function symbols and hence infinite domains. They have very good computational properties, for example ground queries are decidable while in the general case the stable model semantics is highly undecidable. In this paper we prove that a larger class of programs, called finitely recursive programs, preserves most of the good properties of finitary programs under the stable model semantics, namely: (i) finitely recursive programs enjoy a compactness property; (ii) inconsistency checking and skeptical reasoning are semidecidable; (iii) skeptical resolution is complete for normal finitely recursive programs. Moreover, we show how to check inconsistency and answer skeptical queries using finite subsets of the ground program instantiation. We achieve this by extending the splitting sequence theorem by Lifschitz and Turner: We prove that if the input program P is finitely recursive, then the partial stable models determined by any smooth splitting omega-sequence converge to a stable model of P.Comment: 26 pages, Preliminary version in Proc. of ICLP 2007, Best paper awar

Application of a comprehensive methodology for the evaluation of social innovations in rural communities

open4noThis project has received funding from the European Union’s Horizon 2020 Research and Innovation Program under Grant Agreement No. 677622 (H2020 SIMRA–Social Innovation in Marginalised Rural Areas–Project).Despite the growing interest in social innovation (SI) in agriculture, the literature lacks validated tools for evaluating such initiatives. This paper provides an empirical application of the evaluation approach developed within the H2020 SIMRA project to a pilot experience conducted in a rural area of Southern Italy. The value added by this case study is the application of the five types of criteria used by the OECD for the evaluation of development programs, which are commonly referred to as REEIS: relevance, effectiveness, efficiency, impact, and sustainability. This experiment demonstrates the adequacy of the evaluation framework in identifying strengths and weaknesses of the initiative, according to a multifaceted perspective. The overall evaluation proves that most indicators fall under the high (48%) and medium categories (36%), and only few indicators are low (16%). The usefulness of the evaluation results is manifold. First, this evaluation highlights relevant arguments to support the communication strategy addressed at civil society, therefore reinforcing the civic engagement of the initiative, which is the distinctive feature of SI. Second, it supports project managers in addressing interventions to face emerging weaknesses. Finally, the evaluation provides factual evidence to policy makers to perform cost-effective analysis of rural development policies.openBaselice A.; Prosperi M.; Marini Govigli V.; Lopolito A.Baselice A.; Prosperi M.; Marini Govigli V.; Lopolito A

The biofragmentable anastomosis ring in elective colon resections.

Methods. Sixty-eight patients underwent elective colon resection and ìntraperitoneal anastomosis wìth thè biofragmentable anastomosis ring (BAR). Results. Anastomotic dehiscence occurred in 3 patients (4.4%). Two of them had an end-to-end ileocolostomy using a 31 mm BAR. The anastomosis failure was due to ischaemic lesion of thè small bowel dose to thè ileocolostomy, probably caused by a mismatch between thè size of small bowel and that of thè BAR. Another patient experienced anastomosis dehiscence probably due to a faecal impaction into thè BAR. Forty-eight patients (70.5%) experienced troublesome constipation and evacuated after thè sixth postoperative day. A bowel obstruction proximal to thè BAR was documented in 4 cases who have been treated conservatively. Condmions. The low rate of major complications justify thè use of thè BAR in elective colon surgery, but thè surgeon must be aware of tedious postoperative obstructive episodes frequently encountered in this series

Mutations in the SPAST gene causing hereditary spastic paraplegia arerelated to global topological alterations in brain functional networks

Aim: Our aim was to describe the rearrangements of the brain activity related to genetic mutations in the SPAST gene. Methods: Ten SPG4 patients and ten controls underwent a 5 min resting state magnetoencephalography recording and neurological examination. A beamformer algorithm reconstructed the activity of 90 brain areas. The phase lag index was used to estimate synchrony between brain areas. The minimum spanning tree was used to estimate topological metrics such as the leaf fraction (a measure of network integration) and the degree divergence (a measure of the resilience of the network against pathological events). The betweenness centrality (a measure to estimate the centrality of the brain areas) was used to estimate the centrality of each brain area. Results: Our results showed topological rearrangements in the beta band. Specifically, the degree divergence was lower in patients as compared to controls and this parameter related to clinical disability. No differences appeared in leaf fraction nor in betweenness centrality. Conclusion: Mutations in the SPAST gene are related to a reorganization of the brain topology

Probing background ionization: Positive streamers with varying pulse repetition rate and with a radioactive admixture

Positive streamers need a source of free electrons ahead of them to propagate. A streamer can supply these electrons by itself through photo-ionization, or the electrons can be present due to external background ionization. Here we investigate the effects of background ionization on streamer propagation and morphology by changing the gas composition and the repetition rate of the voltage pulses, and by adding a small amount of radioactive Krypton 85. We find that the general morphology of a positive streamer discharge in high purity nitrogen depends on background ionization: at lower background ionization levels the streamers branch more and have a more feather-like appearance. This is observed both when varying the repetition rate and when adding Krypton 85, though side branches are longer with the radioactive admixture. But velocities and minimal diameters of streamers are virtually independent of the background ionization level. In air, the inception cloud breaks up into streamers at a smaller radius when the repetition rate and therefore the background ionization level is higher. When measuring the effects of the pulse repetition rate and of the radioactive admixture on the discharge morphology, we found that our estimates of background ionization levels are consistent with these observations; this gives confidence in the estimates. Streamer channels generally do not follow the paths of previous discharge channels for repetition rates of up to 10 Hz. We estimate the effect of recombination and diffusion of ions and free electrons from the previous discharge and conclude that the old trail has largely disappeared at the moment of the next voltage pulse; therefore the next streamers indeed cannot follow the old trail.Comment: 30 pages, 13 figure

Identifying the fundamental structures and processes of care contributing to emergency general surgery quality using a mixed-methods Donabedian approach

BACKGROUND: Acute Care Surgery (ACS) was developed as a structured, team-based approach to providing round-the-clock emergency general surgery (EGS) care for adult patients needing treatment for diseases such as cholecystitis, gastrointestinal perforation, and necrotizing fasciitis. Lacking any prior evidence on optimizing outcomes for EGS patients, current implementation of ACS models has been idiosyncratic. We sought to use a Donabedian approach to elucidate potential EGS structures and processes that might be associated with improved outcomes as an initial step in designing the optimal model of ACS care for EGS patients. METHODS: We developed and implemented a national survey of hospital-level EGS structures and processes by surveying surgeons or chief medical officers regarding hospital-level structures and processes that directly or indirectly impacted EGS care delivery in 2015. These responses were then anonymously linked to 2015 data from the American Hospital Association (AHA) annual survey, Medicare Provider Analysis and Review claims (MedPAR), 17 State Inpatient Databases (SIDs) using AHA unique identifiers (AHAID). This allowed us to combine hospital-level data, as reported in our survey or to the AHA, to patient-level data in an effort to further examine the role of EGS structures and processes on EGS outcomes. We describe the multi-step, iterative process utilizing the Donabedian framework for quality measurement that serves as a foundation for later work in this project. RESULTS: Hospitals that responded to the survey were primarily non-governmental and located in urban settings. A plurality of respondent hospitals had fewer than 100 inpatient beds. A minority of the hospitals had medical school affiliations. DISCUSSION: Our results will enable us to develop a measure of preparedness for delivering EGS care in the US, provide guidance for regionalized care models for EGS care, tiering of ACS programs based on the robustness of their EGS structures and processes and the quality of their outcomes, and formulate triage guidelines based on patient risk factors and severity of EGS disease. CONCLUSIONS: Our work provides a template for team science applicable to research efforts combining primary data collection (i.e., that derived from our survey) with existing national data sources (i.e., SIDs and MedPAR)

Urban Digital Elevation Model Reconstruction Using Very High Resolution Multichannel InSAR Data

Interferometric synthetic aperture radar (SAR) (InSAR) systems allow 3-D reconstruction of observed scene. In this paper, an innovative approach for phase unwrapping and digital elevation model (DEM) generation using multichannel InSAR data is presented. The proposed algorithm, exploiting both the amplitude and phase of the available complex data, is able to unwrap and simultaneously regularize the observed data. In particular, the exploitation of amplitude data within the unwrapping chain helps in preserving sharp discontinuities typical of urban areas. As a result, the technique provides accurate DEM reconstructions. For this aim, a Markovian approach, together with a new graph-cut-based optimization algorithm, has been considered. The method has been developed specifically to work in urban areas with very high resolution InSAR image stacks, being able to automatically compensate possible phase offsets. Results on both simulated and real case studies are reported, showing the effectiveness of the metho

Key Drivers of the Engagement of Farmers in Social Innovation for Marginalised Rural Areas

The European Union promotes social innovation (SI) initiatives for the support of marginalised rural areas through rural and sustainable development policies. These are based on the engagement of local actors and the strengthening of their mutual relationships to boost the fostering of professional collaborations. In this context, the Horizon 2020 Social Innovation in Marginalised Areas (SIMRA) project elaborated a conceptual framework for characterising the engagement in an SI initiative. Accordingly, this paper aims to demonstrate that engagement relies on specific key drivers, such as the existence of unmet social needs and the role of agency. To this end, a two-step Heckman model was applied to an SI initiative case study called Vàzapp’, a rural hub (agency) located in Southern Italy. It promotes relationships among farmers to valorise the marginalised rural areas. The results appear consistent with the theoretical framework, demonstrating that the farmers’ engagement was motivated by the existence of the aforementioned determinants. The implications are relevant for policymakers, consultants, and social innovators who may incorporate these elements in designing specific SI projects in different contexts

Layover Solution in SAR Imaging: A Statistical Approach

In this letter, a statistical-based approach to recover layover solution in synthetic aperture radar (SAR) images is proposed. The aim of this letter is to develop a methodology in order to separate different scattering contributions collapsed in a single SAR image pixel. After a brief discussion about layover, the proposed model is presented, followed by a discussion about achievable performances using CramerRao lower bounds. In the final part of this letter, the performances of a maximum likelihood estimator are evaluated in a simulated data scenario, showing the effectiveness of the method