Negotiating Temporal Commitments in Cross-Organizational Business Processes

Cross-organizational business processes emerge from the cooperation of intra-organizational business processes through exchange of messages. The involved parties agree on communication protocols, which contain in particular temporal constraints: as obligations on one hand, and as guarantees on the other hand. These constraints form also requirements for the design of the hidden implementation of the processes and are the basis for control decisions for each party. We present a comprehensive methodology for modeling the temporal aspects of cross-organizational business processes, checking dynamic controllability of such processes, and supporting the negotiation of temporal commitments. We do so by computing the consequences of temporal constraints in choreographies, and by computing the weakest preconditions for the dynamic controllability of a participating process

Lifetime and polarization of the radiative decay of excitons, biexcitons and trions in CdSe nanocrystal quantum dots

Using the pseudopotential configuration-interaction method, we calculate the intrinsic lifetime and polarization of the radiative decay of single excitons (X), positive and negative trions (X+ and X−), and biexcitons (XX) in CdSe nanocrystal quantum dots. We investigate the effects of the inclusion of increasingly more complex many-body treatments, starting from the single-particle approach and culminating with the configuration-interaction scheme. Our configuration-interaction results for the size dependence of the single-exciton radiative lifetime at room temperature are in excellent agreement with recent experimental data. We also find the following. (i) Whereas the polarization of the bright exciton emission is always perpendicular to the hexagonal c axis, the polarization of the dark exciton switches from perpendicular to parallel to the hexagonal c axis in large dots, in agreement with experiment. (ii) The ratio of the radiative lifetimes of mono- and biexcitons (X):(XX) is ~1:1 in large dots (R=19.2 Å). This ratio increases with decreasing nanocrystal size, approaching 2 in small dots (R=10.3 Å). (iii) The calculated ratio (X+):(X−) between positive and negative trion lifetimes is close to 2 for all dot sizes considered

Some results and challenges Extending Dynamic Controllability to Agile Controllability in Simple Temporal Networks with Uncertainties

Simple Temporal Networks with Uncertainty (STNU) are an expressive means to represent temporal constraints, requirements, or obligations. They feature contingent timepoints, which are set by the environment with a specified interval. Dynamic controllability is the current most relaxed notion for checking that the constraints are not in conflict. It requires that a timepoint may only depend on earlier timepoints. Agile controllability extends dynamic controllability by taking into account that a later timepoint might already be known earlier and allowing a timepoint to depend on all timepoints whose value is known before. In this report, we formally introduce the notion of an STNU with oracle timepoints, formally define the notion of agile controllability, and discuss approaches for checking agile controllability

Dynamic Controllability of Parameterized CSTNUs

A Conditional Simple Temporal Network with Uncertainty (CSTNU) models temporal constraint satisfaction problems in which the environment sets uncontrollable timepoints and conditions. The executor observes and reacts to such uncontrollable assignments as time advances with the CSTNU execution. However, there exist scenarios in which the occurrence of some future timepoints must be fixed as soon as the execution starts. We call these timepoints \textit{parameters}. For a correct execution, parameters must assume values that guarantee the possibility of satisfying all temporal constraints, whatever the environment decides the execution time for uncontrollable timepoints and the truth value of conditions, i.e., dynamic controllability (DC). Here, we formalize the extension of the CSTNU with parameters. Furthermore, we define a set of rules to check the DC of such extended CSTNU. These rules additionally solve the problem inverse to checking DC: computing restrictions on parameter values that yield DC guarantees. The proposed rules can be composed into a sound and complete procedure

Model-independent determination of the carrier multiplication time constant in CdSe nanocrystals

The experimental determination of the carrier multiplication (CM) time constant is complicated by the fact that this process occurs within the initial few hundreds of femtoseconds after excitation and, in transient-absorption experiments, cannot be separated from the buildup time of the 1p-state population. This work provides an accurate theoretical determination of the electron relaxation lifetime during the last stage of the p-state buildup, in CdSe nanocrystals, in the presence of a single photogenerated hole (no CM) and of a hole plus an additional electron–hole pair (following CM). From the invariance of the 1p buildup time observed experimentally for excitations above and below the CM threshold producing hot carriers with the same average per-exciton excess energy, and the calculated corresponding variations in the electron decay time in the two cases, an estimate is obtained for the carrier multiplication time constant. Unlike previous estimates reported in the literature so far, this result is model-independent, i.e., is obtained without making any assumption on the nature of the mechanism governing carrier multiplication. It is then compared with the time constant calculated, as a function of the excitation energy, assuming an impact-ionization-like process for carrier multiplication (DCM). The two results are in good agreement and show that carrier multiplication can occur on timescales of the order of tens of femtoseconds at energies close to the observed onset. These findings, which are compatible with the fastest lifetime estimated experimentally, confirm the suitability of the impact-ionization model to explain carrier multiplication in CdSe nanocrystals

The Information Carried by Scattered Waves: Near-Field and Nonasymptotic Regimes

The number of spatial degrees of freedom of the field radiated in a two-dimensional setting by a time-harmonic, arbitrary square-integrable current density and in the presence of a random distribution of scattering elements is determined. It is shown that the active power associated to the $k$ th singular value of the near field in the presence of scatterers external to the cut presents a heavy tail decay as a function of its index, rather than the usual exponential attenuation occurring beyond a critical index term observed in free space. This near-field information gain due to scattering was recently anticipated by Janaswamy using a stochastic source model, it is extended here to arbitrary sources, and it is shown to disappear in the limit of large radiating systems. It is also shown that the same information gain and asymptotic cut-off occurs for the singular values of the field radiating in free space. Collectively, these results show that while the presence of scatterers external to the cut can increase the number of channels that can be exploited for communication by the active power in the near field, they do not change the number of channels associated to the field, nor the asymptotic behavior of the number of degrees of freedom

Sirtuin 6 localization at cortical brain level of young diabetic mice

The metabolic syndrome, characterized by visceral obesity, dyslipidaemia, hyperglycaemia and hypertension, has become one of the major public-health challenges worldwide and it is strictly associated with the development of type II diabetes and neurodegenerative diseases (Alberti et al. 2005; Panza et al. 2010). Increased metabolic flux to the brain during overnutrition can orchestrate stress response, blood-brain barrier alteration, microglial cells activation and neuroinflammation (Nerurkar et al., 2011). The protein sirtuin family is a class of nicotinamide adenine dinucleotide (NAD+)-dependent histone deacetylase that act on a variety of targets and so play a key role in central physiological regulation (Sebastian et al., 2012; Wang et al., 2012). To assess the physiopathological significance of sirtuin6 (SIRT6) at brain cortical level, we analysed its specific expression and subcellular localization in young db/db mice, animal model of type II diabetes mellitus, and respective control lean mice. In particular, we analysed the cytoarchitecture of the brain cortex, evaluated SIRT6 expression and its localization by immunohistochemistry comparing young db/db mice to lean control mice, distinguishing among the six cortical layers and between motor and somatosensory cortex. We observed that SIRT6 is mainly localized in the nucleus of both lean and db/db mice. Diabetic mice showed few SIRT6 positive cells respect to lean control mice in all cortical layers without significant differences between motor and somatosensory cortex. No morphological alteration have been find. In conclusion, our findings contribute to further understand SIRT6 protein expression in the early steps of type II diabetes mellitus and suggest its implication in the pathogenic processes of diabetes mellitus and diabetes–induced neurodegeneration

Sirtuin 6 localization at cortical brain level of young diabetic mice

The metabolic syndrome, characterized by visceral obesity, dyslipidaemia, hyperglycaemia and hypertension, has become one of the major public-health challenges worldwide and it is strictly associated with the development of type II diabetes and neurodegenerative diseases (Alberti et al. 2005; Panza et al. 2010). Increased metabolic flux to the brain during overnutrition can orchestrate stress response, blood-brain barrier alteration, microglial cells activation and neuroinflammation (Nerurkar et al., 2011). The protein sirtuin family is a class of nicotinamide adenine dinucleotide (NAD+)-dependent histone deacetylase that act on a variety of targets and so play a key role in central physiological regulation (Sebastian et al., 2012; Wang et al., 2012). To assess the physiopathological significance of sirtuin6 (SIRT6) at brain cortical level, we analysed its specific expression and subcellular localization in young db/db mice, animal model of type II diabetes mellitus, and respective control lean mice. In particular, we analysed the cytoarchitecture of the brain cortex, evaluated SIRT6 expression and its localization by immunohistochemistry comparing young db/db mice to lean control mice, distinguishing among the six cortical layers and between motor and somatosensory cortex. We observed that SIRT6 is mainly localized in the nucleus of both lean and db/db mice. Diabetic mice showed few SIRT6 positive cells respect to lean control mice in all cortical layers without significant differences between motor and somatosensory cortex. No morphological alteration have been find. In conclusion, our findings contribute to further understand SIRT6 protein expression in the early steps of type II diabetes mellitus and suggest its implication in the pathogenic processes of diabetes mellitus and diabetes–induced neurodegeneration

I.S.Mu.L.T - Rotator cuff tears guidelines

Despite the high level achieved in the field of shoulder surgery, a global consensus on rotator cuff tears management is lacking. This work is divided into two main sessions: in the first, we set questions about hot topics involved in the rotator cuff tears, from the etiopathogenesis to the surgical treatment. In the second, we answered these questions by mentioning Evidence Based Medicine. The aim of the present work is to provide easily accessible guidelines: they could be considered as recommendations for a good clinical practice developed through a process of systematic review of the literature and expert opinion, in order to improve the quality of care and rationalize the use of resources