Batalin-Vilkovisky Integrals in Finite Dimensions

The Batalin-Vilkovisky method (BV) is the most powerful method to analyze functional integrals with (infinite-dimensional) gauge symmetries presently known. It has been invented to fix gauges associated with symmetries that do not close off-shell. Homological Perturbation Theory is introduced and used to develop the integration theory behind BV and to describe the BV quantization of a Lagrangian system with symmetries. Localization (illustrated in terms of Duistermaat-Heckman localization) as well as anomalous symmetries are discussed in the framework of BV.Comment: 35 page

A Calculus for Orchestration of Web Services

We introduce COWS (Calculus for Orchestration of Web Services), a new foundational language for SOC whose design has been influenced by WS-BPEL, the de facto standard language for orchestration of web services. COWS combines in an original way a number of ingredients borrowed from well-known process calculi, e.g. asynchronous communication, polyadic synchronization, pattern matching, protection, delimited receiving and killing activities, while resulting different from any of them. Several examples illustrates COWS peculiarities and show its expressiveness both for modelling imperative and orchestration constructs, e.g. web services, flow graphs, fault and compensation handlers, and for encoding other process and orchestration languages

Parameterized Verification of Safety Properties in Ad Hoc Network Protocols

We summarize the main results proved in recent work on the parameterized verification of safety properties for ad hoc network protocols. We consider a model in which the communication topology of a network is represented as a graph. Nodes represent states of individual processes. Adjacent nodes represent single-hop neighbors. Processes are finite state automata that communicate via selective broadcast messages. Reception of a broadcast is restricted to single-hop neighbors. For this model we consider a decision problem that can be expressed as the verification of the existence of an initial topology in which the execution of the protocol can lead to a configuration with at least one node in a certain state. The decision problem is parametric both on the size and on the form of the communication topology of the initial configurations. We draw a complete picture of the decidability and complexity boundaries of this problem according to various assumptions on the possible topologies.Comment: In Proceedings PACO 2011, arXiv:1108.145

Use of organic inputs by arable farmers in six agro-ecological zones across Europe: Drivers and barriers

Soil organic matter (SOM) in agricultural soils builds up via – among others - the use of organic inputs such as straw, compost, farmyard manure or the cultivation of green manures or cover crops. SOM has benefits for long-term soil fertility and can provide ecosystem services. Farmer behaviour is however known to be motivated by a larger number of factors. Using the theory of planned behaviour, we aimed to disentangle these factors. We addressed the following research question: What are currently the main drivers and barriers for arable farmers in Europe to use organic inputs? Our study focuses on six agro-ecological zones in four European countries (Austria, Flanders [Belgium], Italy and the Netherlands) and four practices (straw incorporation, green manure or cover crops, compost and farmyard manure). In a first step, relevant factors were identified for each practice with farmers using 5 to ten semi-structured interviews per agro-ecological zone. In a second step, the relevance of these factors was quantified and they were classified as either drivers or barriers in a large scale farm survey with 1263 farmers. In the semi-structured interviews, 110 factors that influenced farmer decisions to use an organic input were identified. In the larger farm survey, 60% of the factors included were evaluated as drivers, while 40% were evaluated as barriers for the use of organic inputs. Major drivers to use organic inputs were related to the perceived effects on soil quality (such as improved soil structure or reduced erosion) and the positive influence from social referents (such as fellow farmers or agricultural advisors). Major barriers to use organic inputs were financial (increased costs or foregone income) and perceived effects on crop protection (such as increased weeds, pests and diseases, or increased pesticide use). Our study shows that motivating farmers to use organic inputs requires specific guidance on how to adapt cultivation practices to reduce weeds, pests and diseases for specific soil types, weather conditions, and crops. In addition, more research is needed on the long-term financial consequences of using organic inputs

Analysis of SLA compliance in the cloud: An automated, model-based approach

Service Level Agreements (SLA) are commonly used to specify the quality attributes between cloud service providers and the customers. A violation of SLAs can result in high penalties. To allow the analysis of SLA compliance before the services are deployed, we describe in this paper an approach for SLA-aware deployment of services on the cloud, and illustrate its workflow by means of a case study. The approach is based on formal models combined with static analysis tools and generated runtime monitors. As such, it fits well within a methodology combining software development with information technology operations (DevOps)

Severity of left ventricular remodeling defines outcomes and response to therapy in heart failure Valsartan heart failure trial (Val-HeFT) echocardiographic data

AbstractObjectivesThe objective of this study was to test the hypothesis that the severity of left ventricular remodeling predicts the response to treatment and outcomes in chronic heart failure.BackgroundReversal of remodeling should produce the most favorable outcome in patients with the most severe remodeling.MethodsIn 5,010 heart failure patients on background therapy and randomized to valsartan and placebo, serial recordings of left ventricular internal diastolic diameter (LVIDd) and ejection fraction (EF) were read at sites that had to meet qualifying standards before participating. Baseline LVIDd and EF were pooled across treatments and retrospectively grouped by quartiles Q1 to Q4, representing best to worst. Kaplan-Meier survival curves were obtained by the log-rank test. Q1 was compared with Q4 for mortality and combined mortality and morbidity (M + M) from Cox regression risk ratios (RRs). Valsartan versus placebo changes from baseline in LVIDd and EF were analyzed by quartiles from analysis of covariance. Valsartan and placebo were compared by RRs for M + M.ResultsSurvival rates were greater in the better quartiles for LVIDd and EF (p < 0.00001). The RR for Q1 versus Q4 in events approached 0.5 for both LVIDd and EF (p < 0.0001). An LVIDd decrease and EF increase were quartile-dependent and greater with valsartan than placebo at virtually all time points. The RR for M + M outcomes favored valsartan in the worse quartiles.ConclusionsStratification by baseline severity of remodeling showed that patients with worse LVIDd and EF are at highest risk for an event, yet appear to gain the most anti-remodeling effect and clinical benefit with valsartan treatment

Programmability of Chemical Reaction Networks

Motivated by the intriguing complexity of biochemical circuitry within individual cells we study Stochastic Chemical Reaction Networks (SCRNs), a formal model that considers a set of chemical reactions acting on a finite number of molecules in a well-stirred solution according to standard chemical kinetics equations. SCRNs have been widely used for describing naturally occurring (bio)chemical systems, and with the advent of synthetic biology they become a promising language for the design of artificial biochemical circuits. Our interest here is the computational power of SCRNs and how they relate to more conventional models of computation. We survey known connections and give new connections between SCRNs and Boolean Logic Circuits, Vector Addition Systems, Petri Nets, Gate Implementability, Primitive Recursive Functions, Register Machines, Fractran, and Turing Machines. A theme to these investigations is the thin line between decidable and undecidable questions about SCRN behavior

Neuroendocrine predictors of vasoplegia after cardiopulmonary bypass

PURPOSE: Vasoplegia often complicates on-pump cardiac surgery. Systemic inflammatory response induced by extracorporeal circulation represents the major determinant, but adrenal insufficiency and postoperative vasopressin deficiency may have a role. Pathophysiological meaning of perioperative changes in endocrine markers of hydro-electrolyte balance has not still fully elucidated. Objectives of the present research study were to estimate the incidence of vasoplegia in a homogeneous cohort of not severe cardiopathic patients, to define the role of presurgical adrenal insufficiency, to evaluate copeptin and NT-proBNP trends in the perioperative. METHODS: We conducted a prospective cohort study in the cardiac intensive care unit of a tertiary referral center. We evaluated 350 consecutive patients scheduled for cardiac surgery; 55 subjects completed the study. Both standard and low-dose corticotropin stimulation tests were performed in the preoperative; copeptin and NT-proBNP were evaluated in the preoperative (T0), on day 1 (T1) and day 7 (T2) after surgery. RESULTS: Nine subjects (16.3%) developed vasoplegic syndrome with longer bypass and clamping time (p  16.9 pmol/L accurately predicted the syndrome (AUC 0.86, 95% CI 0.73–0.94; OR 1.17, 95% CI 1.04–1.32). An evident correlation was observed at 7 days postoperative between NT-proBNP and copeptin (r 0.88, 95% CI 0.8–0.93; p < 0.001). CONCLUSION: Preoperative impaired response to low-dose ACTH stimulation test is not a risk factor for post-cardiotomic vasoplegia; conversely, higher preoperative copeptin predicts the complication. On-pump cardiac surgery could be an interesting model of rapid heart failure progression