Stratified Programs Research Articles

Epistemic Logic Programs: A Study of Some Properties

Abstract Epistemic logic programs (ELPs), extend answer set programming (ASP) with epistemic operators. The semantics of such programs is provided in terms of world views, which are sets of belief sets, that is, syntactically, sets of sets of atoms. Different semantic approaches propose different characterizations of world views. Recent work has introduced semantic properties that should be met by any semantics for ELPs, like the Epistemic Splitting Property, that, if satisfied, allows to modularly compute world views in a bottom-up fashion, analogously to “traditional” ASP. We analyze the possibility of changing the perspective, shifting from a bottom-up to a top-down approach to splitting. We propose a basic top-down approach, which we prove to be equivalent to the bottom-up one. We then propose an extended approach, where our new definition: (i) is provably applicable to many of the existing semantics; (ii) operates similarly to “traditional” ASP; (iii) provably coincides under any semantics with the bottom-up notion of splitting at least on the class of Epistemically Stratified Programs (which are, intuitively, those where the use of epistemic operators is stratified); (iv) better adheres to common ASP programming methodology.

COVID-19-Related Stress, Fear and Online Teaching Satisfaction among Nursing Students during the COVID-19 Pandemic.

The COVID-19 pandemic has had a significant impact on mental health, particularly among students, due to COVID-19-related fear and also the transition from traditional to online lectures. In this questionnaire-based study, the COVID-19 Stress Scales (CSS), the Fear of COVID-19 Scale (FCV-19S), and the Online Teaching Satisfaction Scale were used to assess COVID-19-related fear, stress, and overall satisfaction with online teaching during the COVID-19 pandemic among nursing students in Serbia. A total of 167 students participated in the study, whose mean age was 21.3 ± 5.3, and the majority of whom were female and first-year students. Overall, most students experienced moderate to extremely high COVID-19-related stress levels. Overall, first-year and fourth-year students scored significantly lower regarding the Xenophobia and Traumatic stress subscales than second-year and third-year students, whereas first-year students also scored significantly lower on the Danger and Contamination subscales. First-year students experienced less COVID-19-related fear compared to senior students. Students were reasonably satisfied with online teaching. A stratified program is needed to prevent further decline of students' mental health and to improve their adaptation through public, health, and educational changes.

P-47 Head and neck squamous cell carcinoma: a stratified follow-up program

P-47 Head and neck squamous cell carcinoma: a stratified follow-up program

Oral maintenance capecitabine versus active monitoring for patients with metastatic colorectal cancer (mCRC) who are stable or responding after 16 weeks of first-line treatment: Results from the randomized FOCUS4-N trial.

3504 Background: There is extensive randomised evidence supporting the use of treatment breaks in mCRC, but breaks from treatment are not universally offered to patients despite reductions in toxicity, without detriment to OS. Prior trials have shown that the combination of Cp and bevacizumab extend PFS but not OS. FOCUS4-N explores oral maintenance Cp monotherapy in patients with disease control on first line therapy. Methods: FOCUS4 was a molecularly stratified trial programme registering patients with newly diagnosed mCRC from 88 hospitals in the UK. Whilst undergoing 16 wks of first line treatment, a sample of tumour was sent for laboratory testing to stratify their disease into molecular subtypes: MSI, BRAF, PIK3CA, TP53 and RAS mutations. For some molecular groups, a targeted therapy subtrial was available but entry into the FOCUS4-N trial was offered to those in whom a targeted subtrial was unavailable. Patients were randomised 1:1 between maintenance Cp therapy or AM. The primary outcome was PFS assessed using 8-wkly RECIST reported CT scans with quality of life (using EQ5D 8 weekly) and OS as secondary outcomes. Toxicity and tolerability were assessed 4-wkly. On progression, from the nadir, patients recommenced first line treatment. Cox regression was used to assess efficacy by intention-to-treat (ITT) with adjustment for tumour location, WHO status, metastatic burden, first line treatment and biomarker subtype. Results: Between March 2014 and March 2020, 254 patients were randomised (127 to Cp and 127 to AM). Baseline characteristics were balanced between groups but event rates were higher than anticipated in the AM group and the final analysis was triggered early as a result of the COVID-19 pandemic halting recruitment. The table presents results for PFS and OS. Compliance with treatment was good with per-protocol analysis results very similar to ITT (PFS HR=0.38 (95% CI 0.28-0.51)). Toxicity from Cp v AM was as expected with G≥2 fatigue (25% v 12%), diarrhoea (23% v 13%) and hand-foot syndrome (26% v 3%). Quality of life showed no statistically significant differences between the two arms. Conclusions: Despite strong evidence of prolongation of PFS with maintenance therapy, OS remains unaffected and FOCUS4-N provides additional evidence to support the use of treatment breaks as a safe management alternative for patients who are stable or responding well to first line treatment for mCRC. Cp without bevacizumab may be used to extend PFS, in the interval after 16 weeks of combination therapy. Clinical trial information: ISRCTN#90061546. [Table: see text]

The Postpartum Hemorrhage Patient Safety Bundle Implementation at a Single Institution: Successes, Failures, and Lessons Learned.

In 2015, a multidisciplinary consensus bundle of recommendations for the anticipation and management of postpartum hemorrhage was published. Our goal was to evaluate the successes and failures of our institutional bundle implementation process. An interdisciplinary committee was created to facilitate bundle implementation. All components of the bundle were addressed with cross-disciplinary teaching between stakeholders on the obstetrics units. Tools were built in the electronic medical record to facilitate bundle components of risk stratification, quantitative blood loss calculation, and stage-based hemorrhage management. Bundle components were individually evaluated for acceptability and sustainability. Overall rates of hemorrhage and transfusion from the periods 1 year before and after bundle implementation were also evaluated. Readiness bundle components were successfully implemented, although simulation drills demonstrated limited sustainability. Recognition components were mixed: risk stratification was successfully and sustainably implemented while quantitative blood loss met resistance and was ultimately discontinued as it did not clinically perform superiorly to estimated blood loss. Among response and reporting elements, patient level support and team debriefing were noted as particular deficiencies in our program. The postpartum hemorrhage patient safety bundle provided concrete individual elements, which overall improved the success of a stratified program implementation. Multiple deficiencies in acceptability and sustainability were uncovered during our process, particularly concerns about quantitative blood loss implementation and team communication skills. · Supply readiness and protocol development were "quick wins.". · Culture change elements included recognition, response, and communication.. · Dedicated champions and electronic medical record tools improved sustainability.. · Poor acceptability and lack of improved outcomes led to element failure..

A Case for Stale Synchronous Distributed Model for Declarative Recursive Computation

AbstractA large class of traditional graph and data mining algorithms can be concisely expressed in Datalog, and other Logic-based languages, once aggregates are allowed in recursion. In fact, for most BigData algorithms, the difficult semantic issues raised by the use of non-monotonic aggregates in recursion are solved byPre-Mappability(${\cal P}$reM), a property that assures that for a program with aggregates in recursion there is an equivalent aggregate-stratified program. In this paper we show that, by bringing together the formal abstract semantics of stratified programs with the efficient operational one of unstratified programs,$\[{\cal P}\]$reMcan also facilitate and improve their parallel execution. We prove that$\[{\cal P}\]$reM-optimized lock-free and decomposable parallel semi-naive evaluations produce the same results as the single executor programs. Therefore,$\[{\cal P}\]$reMcan be assimilated into the data-parallel computation plans of different distributed systems, irrespective of whether these follow bulk synchronous parallel (BSP) or asynchronous computing models. In addition, we show that non-linear recursive queries can be evaluated using a hybrid stale synchronous parallel (SSP) model on distributed environments. After providing a formal correctness proof for the recursive query evaluation with$\[{\cal P}\]$reMunder this relaxed synchronization model, we present experimental evidence of its benefits.

The basics of epithelial-mesenchymal transition (EMT): A study from a structure, dynamics, and functional perspective.

Epithelial-mesenchymal transition (EMT) is a key step in transdifferentiation process in solid cancer development. Forthcoming evidence suggest that the stratified program transforms polarized, immotile epithelial cells to migratory mesenchymal cells associated with enhancement of breast cancer stemness, metastasis, and drug resistance. It involves primarily several signaling pathways, such as transforming growth factor-β (TGF-β), cadherin, notch, plasminogen activator protein inhibitor, urokinase plasminogen activator, and WNT/beta catenin pathways. However, current understanding on the crosstalk of multisignaling pathways and assemblies of key transcription factors remain to be explored. In this review, we focus on the crosstalk of signal transduction pathways linked to the current therapeutic and drug development strategies. We have also performed the computational modeling on indepth the structure and conformational dynamic studies of regulatory proteins and analyze molecular interactions with their associate factors to understand the complicated process of EMT in breast cancer progression and metastasis. Electrostatic potential surfaces have been analyzed that help in optimization of electrostatic interactions between the protein and its ligand. Therefore, understanding the biological implications underlying the EMT process through molecular biology with biocomputation and structural biology approaches will enable the development of new therapeutic strategies to sensitize tumors to conventional therapy and suppress their metastatic phenotype.

Secondary prevention of chronic musculoskeletal pain: A systematic review of clinical trials.

Chronic musculoskeletal pain disorders are highly prevalent and have high personal and societal cost. Hence, early detection and care of patients at risk of developing chronic pain is important. Risk factors are well known and screening tools exist, but much less is known about the care of at-risk patients. The aim of this study was to investigate the effectiveness of secondary prevention strategies for musculoskeletal pain. We performed a systematic review of clinical trials in which treatments were adjusted to the risk of chronicity in adults with acute or subacute musculoskeletal pain. Clinical trials, systematic reviews and meta-analyses published after January 1, 2000 were searched in PubMed and PEDro databases and in the reference list of relevant papers. The risk of bias was assessed by the PEDro score. We identified 4807 potentially eligible articles; 13, corresponding to 9 studies, met the inclusion criteria. Most studies investigated low back pain. The overall risk of bias was moderate, mainly because of the difficulty of blinding in physiotherapy studies. As compared with a "one-size-fits-all" treatment, stratified programmes showed significant improvements in several domains of the International Classification of Functioning, Disability and Health: body structures and functions (pain, mood), activities (functional capacity), participation (return to work, quality of life), as well as environmental factors (healthcare consumption). Effect sizes were moderate. Overall, simple educational messages seemed sufficient for low-risk patients. Medium- and high-risk patients benefited from a physical reactivation programme combined with education. In high-risk patients, an additional cognitive-behavioural intervention further improved the outcome. A stratified approach seems effective in reducing long-term disability in patients with musculoskeletal pain. However, more research is necessary to confirm these results.

The intricacies of three-valued extensional semantics for higher-order logic programs

AbstractM. Bezem defined an extensional semantics for positive higher-order logic programs. Recently, it was demonstrated by Rondogiannis and Symeonidou that Bezem's technique can be extended to higher-order logic programs with negation, retaining its extensional properties, provided that it is interpreted under a logic with an infinite number of truth values. Rondogiannis and Symeonidou also demonstrated that Bezem's technique, when extended under the stable model semantics, does not in general lead to extensional stable models. In this paper, we consider the problem of extending Bezem's technique under the well-founded semantics. We demonstrate that the well-founded extensionfailsto retain extensionality in the general case. On the positive side, we demonstrate that for stratified higher-order logic programs, extensionality is indeed achieved. We analyze the reasons of the failure of extensionality in the general case, arguing that a three-valued setting cannot distinguish between certain predicates that appear to have a different behaviour inside a program context, but which happen to be identical as three-valued relations.

116 Gene mutation profile of non-smokers compared to smokers participating in the CRUK stratified medicines programme at a single institution

116 Gene mutation profile of non-smokers compared to smokers participating in the CRUK stratified medicines programme at a single institution

Base Station Placement for Wireless Sensor Network Positioning System via Lexicographical Stratified Programming

This paper investigates optimization-based base station (BS) placement. An optimization model is defined and the BS placement problem is transformed to a lexicographical stratified programming (LSP) model for a given trajectory, according to different accuracy requirements. The feasible region for BS deployment is obtained from the positioning system requirement, which is also solved with signal coverage problem in BS placement. The LSP mathematical model is formulated with the average geometric dilution of precision (GDOP) as the criterion. To achieve an optimization solution, a tolerant factor based complete stratified series approach and grid searching method are utilized to obtain the possible optimal BS placement. Because of the LSP model utilization, the proposed algorithm has wider application scenarios with different accuracy requirements over different trajectory segments. Simulation results demonstrate that the proposed algorithm has better BS placement result than existing approaches for a given trajectory.

Semantic-based construction of arguments: An answer set programming approach

In this paper, we introduce an argumentation approach which takes an extended logic program as input and gives a set of arguments with the respective disagreements among them as output. We establish the notion of an argument under the Well-Founded semantics and Stable semantics inferences, allowing us to identify arguments with stratified programs as support, even when the input for the argument engine is a non-stratified program. We propose a set of rationality postulates for argument-based systems under extended logic programs, which are based on a definition of closure for a set of clauses that considers the well-known Gelfond–Lifschitz reduction. We establish the conditions under which our approach satisfies these principles. In addition, we present a standalone argumentation-tool based on the XSB system which implements our argumentation approach.

Terminating Evaluation of Logic Programs with Finite Three-Valued Models

As evaluation methods for logic programs have become more sophisticated, the classes of programs for which termination can be guaranteed have expanded. From the perspective of ar set programs that include function symbols, recent work has identified classes for which grounding routines can terminate either on the entire program [Calimeri et al. 2008] or on suitable queries [Baselice et al. 2009]. From the perspective of tabling, it has long been known that a tabling technique called subgoal abstraction provides good termination properties for definite programs [Tamaki and Sato 1986], and this result was recently extended to stratified programs via the class of bounded term-size programs [Riguzzi and Swift 2013]. In this article, we provide a formal definition of tabling with subgoal abstraction resulting in the SLG SA algorithm. Moreover, we discuss a declarative characterization of the queries and programs for which SLG SA terminates. We call this class strongly bounded term-size programs and show its equivalence to programs with finite well-founded models. For normal programs, strongly bounded term-size programs strictly includes the finitely ground programs of Calimeri et al. [2008]. SLG SA has an asymptotic complexity on strongly bounded term-size programs equal to the best known and produces a residual program that can be sent to an answer set programming system. Finally, we describe the implementation of subgoal abstraction within the SLG-WAM of XSB and provide performance results.

Spatial distribution of San José scale Diaspidiotus perniciosus (Hemiptera: Diaspididae) on an apple tree

Five distinct infestations of San José scale (Diaspidiotus perniciosus) were identified on a single vase-shaped ‘Red Delicious’ apple tree, and a stratified random sampling programme of the population was carried out from September 1969 to September 1970. All live and dead scale insects, except crawlers, were counted fortnightly on samples of bark, fruit and leaves from the trunk, leaders, main branches, twigs, fruit spurs and new shoots within the strata (50 samples/sampling occasion). The strata were below, within and above the five infestations, and the stages recorded were settled 1st instar, 2nd instar, prepupal male, pupal male, adult male and adult female (with and without crawlers). Density was expressed as numbers per cm2 of bark, and numbers per fruit and leaf. At harvest, total scale insects (but not the separate stages) were counted on each fruit within each stratum. Analyses showed that, with the exception of adult females on the leaves, all stages were aggregated. Density varied greatly within the tree. Highest densities occurred within the infestations compared with above and below the infestations; two of the leader infestations had higher densities than the others and the trunk infestation; densities on the bark>fruit>leaves. Sex ratios were male-dominated on the leaves. Regressions of scale insects per fruit on their density on the bark were always significant, but scale density on the bark of the fruit spurs was the best predictor of scale insects per fruit, which was further related to percentage fruit infestation by logistic regression. These analyses confirmed infestation rates of fruit spurs as the most reliable and practical sampling unit for determining the need for control measures.

Influence of Age, Sex, Technique, and Exercise Program on Movement Patterns after an Anterior Cruciate Ligament Injury Prevention Program in Youth Soccer Players

Background Anterior cruciate ligament (ACL) injury prevention programs show promising results with changing movement; however, little information exists regarding whether a program designed for an individual's movements may be effective or how baseline movements may affect outcomes. Hypothesis A program designed to change specific movements would be more effective than a “one-size-fits-all” program. Greatest improvement would be observed among individuals with the most baseline error. Subjects of different ages and sexes respond similarly. Study Design Randomized controlled trial; Level of evidence, 1. Methods One hundred seventy-three youth soccer players from 27 teams were randomly assigned to a generalized or stratified program. Subjects were videotaped during jump-landing trials before and after the program and were assessed using the Landing Error Scoring System (LESS), which is a valid clinical movement analysis tool. A high LESS score indicates more errors. Generalized players performed the same exercises, while the stratified players performed exercises to correct their initial movement errors. Change scores were compared between groups of varying baseline errors, ages, sexes, and programs. Results Subjects with the highest baseline LESS score improved the most (95% CI, −3.4 to −2.0). High school subjects (95% CI, −1.7 to −0.98) improved their technique more than pre–high school subjects (95% CI, −1.0 to −0.4). There was no difference between the programs or sexes. Conclusions Players with the greatest amount of movement errors experienced the most improvement. A program's effectiveness may be enhanced if this population is targeted.

Combined Support Force 536: Operation Unified Assistance

The coordinated and combined use of military and civilian resources in response to large-scale natural disasters have not been frequent or well documented. Historically, the overall efficacy and successes of such endeavors are mixed. The benefits of early decisive military leadership, time-phased implementation of resources, a stratified assistance program, and a working relationship is illustrated during the tragic Asian tsunami disaster of 2004 to 2005. The tasking of III Marine Expeditionary Force and my experience as Joint Task Force Surgeon suggest deliberate civil-military planning is beneficial and can significantly reduce human suffering.

Soil information for agricultural decision making: a New Zealand perspective

AbstractUnderstanding of the soil resource is pivotal to our ability to use, manage and modify soils effectively and responsibly. Yet those who make the most decisions concerning soil use and management – farmers and landholders – rarely have access to reliable soil information at scales suitable for farm decision making. By default, many rely on limited local soil knowledge when making decisions that determine farm performance and environmental impact. Providing detailed nationwide soil information that is appropriate for farm decision making is feasible, as demonstrated by the achievements of several European countries and the USA. For New Zealand, a stratified programme at scales of 1:10 000 for versatile land; 1:25 000 for other agricultural land; and 1:50 000 for non‐domesticated land, would cost NZD $280 million, or NZD $11.2 million per year if spread over the useful life of the information. This investment is small relative to the economic value of agriculture, and necessary if New Zealand is to make meaningful advances in reducing current agri‐environmental trends.

Temporal stratification tests for linear and branching-time deductive databases

We consider the problem of extending temporal deductive databases with stratified negation. We argue that the classical stratification test for deductive databases is too restrictive when one shifts attention to the temporal case. Moreover, as we demonstrate, the (more general) local stratification approach is impractical: detecting whether a temporal deductive database is locally stratified is shown to be co-NP hard (even if one restricts attention to programs that only use one predicate symbol and two constants). For these reasons we define temporal stratification, an intermediate notion between stratification and local stratification. We demonstrate that for the temporal deductive databases we consider, temporal stratification coincides with local stratification in certain important cases in which the latter is polynomial-time decidable. We then develop two algorithms for detecting temporal stratification. The first algorithm applies to linear-time temporal deductive databases and it is efficient and more general than existing approaches; however, the algorithm sacrifices completeness for efficiency since it does not cover the whole class of temporally stratified programs. The second algorithm applies to branching-time temporal deductive databases (which include as a special case the linear-time ones). This algorithm is more expensive from a computational point of view, but it covers the whole class of temporally stratified programs. We discuss the relative merits of the two algorithms and compare them with other existing approaches.

STRPRO Tool for Manipulation of Stratified Programs Based on SEPN

Negation is useful in the majority of the real world applications. However, its introduction leads to semantic and canonical problems. SEPN nets are well adapted extension of predicate nets for the definition and manipulation of stratified programs. This formalism is characterized by two main contributions. The first concerns the management of the whole class of stratified programs. The second contribution is related to usual operations optimization (maximal stratification, incremental updates …). We propose, in this paper, useful algorithms for manipulating stratified programs using SEPN. These algorithms were implemented and validated with STRPRO tool.

Symmetric structure in logic programming

It is argued that some symmetric structure in logic programs could be taken into account when implementing semantics in logic programming. This may enhance the declarative ability or expressive power of the semantics. The work presented here may be seen as representative examples along this line. The focus is on the derivation of negative information and some other classic semantic issues. We first define a permutation group associated with a given logic program. Since usually the canonical models used to reflect the common sense or intended meaning are minimal or completed models of the program, we expose the relationships between minimal models and completed models of the original program and its so-called G-reduced form newly-derived via the permutation group defined. By means of this G-reduced form, we introduce a rule to assume negative information termed G-CWA, which is actually a generalization of the GCWA. We also develop the notions of G-definite, G-hierarchical and G-stratified logic programs, which are more general than definite, hierarchical and stratified programs, and extend some well-known declarative and procedural semantics to them, respectively.