The Nonlinear Schrodinger Equation on the Half Line

The nonlinear Schrodinger equation on the half line with mixed boundary condition is investigated. After a brief introduction to the corresponding classical boundary value problem, the exact second quantized solution of the system is constructed. The construction is based on a new algebraic structure, which is called in what follows boundary algebra and which substitutes, in the presence of boundaries, the familiar Zamolodchikov-Faddeev algebra. The fundamental quantum field theory properties of the solution are established and discussed in detail. The relative scattering operator is derived in the Haag-Ruelle framework, suitably generalized to the case of broken translation invariance in space.Comment: Tex file, no figures, 32 page

Primordial non-Gaussianity and Bispectrum Measurements in the Cosmic Microwave Background and Large-Scale Structure

The most direct probe of non-Gaussian initial conditions has come from bispectrum measurements of temperature fluctuations in the Cosmic Microwave Background and of the matter and galaxy distribution at large scales. Such bispectrum estimators are expected to continue to provide the best constraints on the non-Gaussian parameters in future observations. We review and compare the theoretical and observational problems, current results and future prospects for the detection of a non-vanishing primordial component in the bispectrum of the Cosmic Microwave Background and large-scale structure, and the relation to specific predictions from different inflationary models.Comment: 82 pages, 23 figures; Invited Review for the special issue "Testing the Gaussianity and Statistical Isotropy of the Universe" for Advances in Astronom

General CMB and Primordial Bispectrum Estimation I: Mode Expansion, Map-Making and Measures of f_NL

We present a detailed implementation of two bispectrum estimation methods which can be applied to general non-separable primordial and CMB bispectra. The method exploits bispectrum mode decompositions on the domain of allowed wavenumber or multipole values. Concrete mode examples constructed from symmetrised tetrahedral polynomials are given, demonstrating rapid convergence for known bispectra. We use these modes to generate simulated CMB maps of high resolution (l > 2000) given an arbitrary primordial power spectrum and bispectrum or an arbitrary late-time CMB angular power spectrum and bispectrum. By extracting coefficients for the same separable basis functions from an observational map, we are able to present an efficient and general f_NL estimator for a given theoretical model. The estimator has two versions comparing theoretical and observed coefficients at either primordial or late times, thus encompassing a wider range of models, including secondary anisotropies, lensing and cosmic strings. We provide examples and validation of both f_NL estimation methods by direct comparison with simulations in a WMAP-realistic context. In addition, we show how the full bispectrum can be extracted from observational maps using these mode expansions, irrespective of the theoretical model under study. We also propose a universal definition of the bispectrum parameter F_NL for more consistent comparison between theoretical models. We obtain WMAP5 estimates of f_NL for the equilateral model from both our primordial and late-time estimators which are consistent with each other, as well as with results already published in the literature. These general bispectrum estimation methods should prove useful for the analysis of nonGaussianity in the Planck satellite data, as well as in other contexts.Comment: 41 pages, 17 figure

Separating the North and South Pacific Meridional Modes Contributions to ENSO and Tropical Decadal Variability

North and South Pacific Meridional Modes (NPMM and SPMM) are known precursors of El Niño–Southern Oscillation (ENSO) and Tropical Pacific decadal variability (TPDV). However, the relative importance of these precursors and the timescale on which they impact the tropics remain unclear. Using a 30-member ensemble of the Community Earth System Model as the control climate, we generate two additional members where the NPMM and SPMM are selectively suppressed. We find that both meridional modes energize the tropical variance independently on different timescales. The absence of NPMM leads to a significant reduction of the tropical interannual variability (~35%), while the absence of the SPMM has no appreciable impact on ENSO but significantly reduces the TPDV (~30%). While the relative importance of the NPMM and SPMM may be model dependent, the stochastic atmospheric variability in the extratropics that energizes the meridional modes emerges as a key source of TPDV

The genetics of diabetes: What we can learn from Drosophila

Diabetes mellitus is a heterogeneous disease characterized by hyperglycemia due to impaired insulin secretion and/or action. All diabetes types have a strong genetic component. The most frequent forms, type 1 diabetes (T1D), type 2 diabetes (T2D) and gestational diabetes mellitus (GDM), are multifactorial syndromes associated with several genes’ effects together with environmental factors. Conversely, rare forms, neonatal diabetes mellitus (NDM) and maturity onset diabetes of the young (MODY), are caused by mutations in single genes. Large scale genome screenings led to the identification of hundreds of putative causative genes for multigenic diabetes, but all the loci identified so far explain only a small proportion of heritability. Nevertheless, several recent studies allowed not only the identification of some genes as causative, but also as putative targets of new drugs. Although monogenic forms of diabetes are the most suited to perform a precision approach and allow an accurate diagnosis, at least 80% of all monogenic cases remain still undiag-nosed. The knowledge acquired so far addresses the future work towards a study more focused on the identification of diabetes causal variants; this aim will be reached only by combining expertise from different areas. In this perspective, model organism research is crucial. This review traces an overview of the genetics of diabetes and mainly focuses on Drosophila as a model system, describing how flies can contribute to diabetes knowledge advancement

Entrepreneurial value creation: conceptualizing an exchange-based view of entrepreneurship

4sìopenPurpose: This paper proposes an Exchange-Based View of the value creation process. The Borrowing from marketing literature, the EBV advances that entrepreneurs and stakeholders are tied by exchange relationships, through which they co-create value by reciprocally making and realizing promises of value. Design/methodology/approach: Propositions are developed and offered to advance the role of exchange in the entrepreneurial value creation process. Findings: The authors conceptualize the enterprise as a system of exchange relationships between entrepreneurs and their stakeholders, thus proposing an exchange-based view of entrepreneurship. Originality/value: Such an account of the role of entrepreneurs and of their relationship with the stakeholders has meaningful implications for our understanding of the entrepreneurial tasks of opportunity recognition and exploitation.openPinelli M.; Lechner C.; Kraus S.; Liguori E.Pinelli, M.; Lechner, C.; Kraus, S.; Liguori, E

interface trap state characterization of metal insulator semiconductor structures based on photosensitive organic materials

Abstract Flexible organic and printed electronics has led in the last years to exciting applications, especially for what concerns devices incorporating photosensitive materials. Among the latter, organic field-effect phototransistors are a promising technology because of the high light-sensitivity and the possibility of being integrated within more complex systems. Nevertheless, their optimization has not been thoroughly investigated and considerable variations are often observed in their behavior. In this framework, the most critical aspect is represented by the interface formed between the organic semiconductor and the employed dielectric layer. In our contribution, we have fabricated metal-insulator-semiconductor (MIS) structures based on the archetypal photosensitive organic materials poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PC 61 BM) on Silicon/SiO 2 substrates, exploiting their blend in a bulk heterojunction configuration. The MIS structures have been characterized by means of admittance spectroscopy to study the properties of the trap distribution at the interface between the organic semiconductors and the silicon oxide insulating layer. The complex behavior of the capacitance and loss diagrams has been interpreted with a simple electrical model to extract the density of the traps at the interface between the insulator and the semiconductor. It is shown that in the blend-based MIS device several peaks arise in the loss diagram with respect to the only P3HT MIS device. This could be attributed to a different interaction between the single species in the bulk heterojunction and the silicon oxide layer. Furthermore, the reported values of trap densities result in the range of those determined for analogous structures and materials

MICROTROMBOSI SINUSOIDALE EPATICA INDOTTA DAL LIPOPOLISACCARIDE: RUOLO PROTETTIVO DELLA SIMVASTATINA IN UN MODELLO MURINO DI ENDOTOSSIEMIA

Background:Liver dysfunction is one of the earliest high-risk markers for multi-organ failure (MOF) in patients with sepsis. In a recent study, using a murine model, we demonstrated that lipopolysaccharide (LPS) injection provokes hepatic microvascular dysfunction, associated with marked endothelitis in perisinusoidal areas. Furthermore, endothelial dysfunction drives vascular derangement and organ failure associated with sepsis. However, the consequences of sepsis on liver sinusoidal endothelial function are unknown. Statins might improve microvascular dysfunction in sepsis. The present study explores liver vascular abnormalities and the effects of statins in a rat model of endotoxemia. Methods: For this purpose, lipopolysaccharide (LPS) or saline was given to: (1) rats treated with placebo; (2) rats treated with simvastatin (25 mg/kg, orally), given at 3 and 23 hours after LPS/saline challenge; (3) rats treated with simvastatin (25 mg/kg/24 h, orally) from 3 days before LPS/saline injection. Liver microvascular function was assessed by molecular studies and liver function tests. Results: At 24 h, LPS induced liver endothelial dysfunction, as shown by a decreased of thrombomodulin and a increase of fibrin. Treatment with simvastatin from 3 days before LPS prevented the increase of fibrin. Conclusions: LPS administration induces intrahepatic endothelial dysfunction that might be prevented by simvastatin, suggesting that statins might have potential for liver protection during endotoxemia