Analytic Kramer kernels, Lagrange-type interpolation series and de Branges spaces

The classical Kramer sampling theorem provides a method for obtaining orthogonal sampling formulas. In particular, when the involved kernel is analytic in the sampling parameter it can be stated in an abstract setting of reproducing kernel Hilbert spaces of entire functions which includes as a particular case the classical Shannon sampling theory. This abstract setting allows us to obtain a sort of converse result and to characterize when the sampling formula associated with an analytic Kramer kernel can be expressed as a Lagrange-type interpolation series. On the other hand, the de Branges spaces of entire functions satisfy orthogonal sampling formulas which can be written as Lagrange-type interpolation series. In this work some links between all these ideas are established

The shape of our gut: Dissecting its impact on drug absorption in a 3D bioprinted intestinal model

The small intestine is a complex organ with a characteristic architecture and a major site for drug and nutrient absorption. The three-dimensional (3D) topography organized in finger-like protrusions called villi increases surface area remarkably, granting a more efficient absorption process. The intestinal mucosa, where this process occurs, is a multilayered and multicell-type tissue barrier. In vitro intestinal models are routinely used to study different physiological and pathological processes in the gut, including compound absorption. Still, standard models are typically two-dimensional (2D) and represent only the epithelial barrier, lacking the cues offered by the 3D architecture and the stromal components present in vivo, often leading to inaccurate results. In this work, we studied the impact of the 3D architecture of the gut on drug transport using a bioprinted 3D model of the intestinal mucosa containing both the epithelial and the stromal compartments. Human intestinal fibroblasts were embedded in a previously optimized hydrogel bioink, and enterocytes and goblet cells were seeded on top to mimic the intestinal mucosa. The embedded fibroblasts thrived inside the hydrogel, remodeling the surrounding extracellular matrix. The epithelial cells fully covered the hydrogel scaffolds and formed a uniform cell layer with barrier properties close to in vivo. In particular, the villus-like model revealed overall increased permeability compared to a flat counterpart composed by the same hydrogel and cells. In addition, the efflux activity of the P-glycoprotein (P-gp) transporter was significantly reduced in the villus-like scaffold compared to a flat model, and the genetic expression of other drugs transporters was, in general, more relevant in the villus-like model. Globally, this study corroborates that the presence of the 3D architecture promotes a more physiological differentiation of the epithelial barrier, providing more accurate data on drug absorbance measurements.Copyright © 2023. Published by Elsevier B.V

Browser-based Data Annotation, Active Learning, and Real-Time Distribution of Artificial Intelligence Models: From Tumor Tissue Microarrays to COVID-19 Radiology.

BACKGROUND: Artificial intelligence (AI) is fast becoming the tool of choice for scalable and reliable analysis of medical images. However, constraints in sharing medical data outside the institutional or geographical space, as well as difficulties in getting AI models and modeling platforms to work across different environments, have led to a "reproducibility crisis" in digital medicine. METHODS: This study details the implementation of a web platform that can be used to mitigate these challenges by orchestrating a digital pathology AI pipeline, from raw data to model inference, entirely on the local machine. We discuss how this federated platform provides governed access to data by consuming the Application Program Interfaces exposed by cloud storage services, allows the addition of user-defined annotations, facilitates active learning for training models iteratively, and provides model inference computed directly in the web browser at practically zero cost. The latter is of particular relevance to clinical workflows because the code, including the AI model, travels to the user's data, which stays private to the governance domain where it was acquired. RESULTS: We demonstrate that the web browser can be a means of democratizing AI and advancing data socialization in medical imaging backed by consumer-facing cloud infrastructure such as Box.com. As a case study, we test the accompanying platform end-to-end on a large dataset of digital breast cancer tissue microarray core images. We also showcase how it can be applied in contexts separate from digital pathology by applying it to a radiology dataset containing COVID-19 computed tomography images. CONCLUSIONS: The platform described in this report resolves the challenges to the findable, accessible, interoperable, reusable stewardship of data and AI models by integrating with cloud storage to maintain user-centric governance over the data. It also enables distributed, federated computation for AI inference over those data and proves the viability of client-side AI in medical imaging. AVAILABILITY: The open-source application is publicly available at , with a short video demonstration at

Quantum Simulation of Spin Chains Coupled to Bosonic Modes with Superconducting Circuits

We propose the implementation of a digital quantum simulation of spin chains coupled to bosonic field modes in superconducting circuits. Gates with high fidelities allows one to simulate a variety of Ising magnetic pairing interactions with transverse field, Tavis-Cummings interaction between spins and a bosonic mode, and a spin model with three-body terms. We analyze the feasibility of the implementation in realistic circuit quantum electrodynamics setups, where the interactions are either realized via capacitive couplings or mediated by microwave resonators.Comment: Chapter in R. S. Anderssen et al. (eds.), Mathematics for Industry 11 (Springer Japan, 2015

Intraoperative PaO2 is not related to the development of surgical site infections after major cardiac surgery

Producción CientíficaBackground: The perioperative use of high inspired oxygen fraction (FIO2) for preventing surgical site infections (SSIs) has demonstrated a reduction in their incidence in some types of surgery however there exist some discrepancies in this respect. The aim of this study was to analyze the relationship between PaO2 values and SSIs in cardiac patients. Methods: We designed a prospective study in which 1,024 patients undergoing cardiac surgery were analyzed. Results: SSIs were observed in 5.3% of patients. There was not significant difference in mortality at 30 days between patients with and without SSIs. In the uni and multivariate analysis no differences in function of the inspired oxygen fraction administrated were observed. Conclusions: We observed that the PaO2 in adult cardiac surgery patients was not related to SSI rate

Evolutionary and pulsational properties of white dwarf stars

Abridged. White dwarf stars are the final evolutionary stage of the vast majority of stars, including our Sun. The study of white dwarfs has potential applications to different fields of astrophysics. In particular, they can be used as independent reliable cosmic clocks, and can also provide valuable information about the fundamental parameters of a wide variety of stellar populations, like our Galaxy and open and globular clusters. In addition, the high densities and temperatures characterizing white dwarfs allow to use these stars as cosmic laboratories for studying physical processes under extreme conditions that cannot be achieved in terrestrial laboratories. They can be used to constrain fundamental properties of elementary particles such as axions and neutrinos, and to study problems related to the variation of fundamental constants. In this work, we review the essentials of the physics of white dwarf stars. Special emphasis is placed on the physical processes that lead to the formation of white dwarfs as well as on the different energy sources and processes responsible for chemical abundance changes that occur along their evolution. Moreover, in the course of their lives, white dwarfs cross different pulsational instability strips. The existence of these instability strips provides astronomers with an unique opportunity to peer into their internal structure that would otherwise remain hidden from observers. We will show that this allows to measure with unprecedented precision the stellar masses and to infer their envelope thicknesses, to probe the core chemical stratification, and to detect rotation rates and magnetic fields. Consequently, in this work, we also review the pulsational properties of white dwarfs and the most recent applications of white dwarf asteroseismology.Comment: 85 pages, 28 figures. To be published in The Astronomy and Astrophysics Revie

Klebsiella pneumoniae is able to trigger epithelial-mesenchymal transition process in cultured airway epithelial cells

The ability of some bacterial pathogens to activate Epithelial-Mesenchymal Transition normally is a consequence of the persistence of a local chronic inflammatory response or depends on a direct interaction of the pathogens with the host epithelial cells. In this study we monitored the abilities of the K. pneumoniae to activate the expression of genes related to EMT-like processes and the occurrence of phenotypic changes in airway epithelial cells during the early steps of cell infection. We describe changes in the production of intracellular reactive oxygen species and increased HIF-1α mRNA expression in cells exposed to K. pneumoniae infection. We also describe the upregulation of a set of transcription factors implicated in the EMT processes, such as Twist, Snail and ZEB, indicating that the morphological changes of epithelial cells already appreciable after few hours from the K. pneumoniae infection are tightly regulated by the activation of transcriptional pathways, driving epithelial cells to EMT. These effects appear to be effectively counteracted by resveratrol, an antioxidant that is able to exert a sustained scavenging of the intracellular ROS. This is the first report indicating that strains of K. pneumoniae may promote EMT-like programs through direct interaction with epithelial cells without the involvement of inflammatory cells

LOGISTICS PERFORMANCE AND EXPORT COMPETITIVENESS: EUROPEAN EXPERIENCE

This article aims to analyse the importance of logistics performance in European Union (EU) exports over a sample period in order to detect possible advances on behalf of Member States. We will estimate several gravity equations using the Logistics Performance Index (LPI) and its components as characteristic proxy variables of trade facilitation. In order to avoid the possible heterogeneity caused by sample bias, we will employ the two-stage model proposed by Heckman. The estimations of the gravity models using the two-stage Heckman model for 26 EU countries lead to the conclusion that logistics were more important for exporting nations than importing nations in both 2005 and 2010, reinforcing the interest in the exporter side of the paper. In reference to the components of the LPI, Competence and Tracking have acquired greater importance in recent years, in keeping with the weak domestic demand in European countries and their search for new international markets.Puertas Medina, RM.; Martí Selva, ML.; Garcia Menendez, L. (2013). LOGISTICS PERFORMANCE AND EXPORT COMPETITIVENESS: EUROPEAN EXPERIENCE. Empirica. 1-14. doi:10.1007/s10663-013-9241-zS114Anderson JE (1979) A theorical foundation to the gravity equation. Am Econ Rev 69: 106–116 http://www.jstor.org/stable/1802501Anderson J, Van Wincoop E (2003) Gravity with gravitas: a solution to the border puzzle. Am Econ Rev 93:170–192. doi: 10.1257/000282803321455214Arvis JF, Mustra M, Ojala L, Shepherd B, Saslavsky D (2007) Connecting to compete: trade logistics in the global economy. World Bank, WashingtonArvis JF, Mustra M, Panzer J, Ojala L, Naula T (2010) Connecting to compete: trade logistics in the global economy. World Bank, WashingtonArvis JF, Mustra M, Ojala L, Shepherd B, Saslavsky D (2012) Connecting to compete: trade logistics in the global economy. World Bank, WashingtonBehar A, Manner P (2008) Logistics and exports. African economics working paper series 293. CSAE WPS/2008-13. University of Oxford, OxfordBehar A, Venables AJ (2010) Transport costs and international trade. In: Palma A, Lindsey R, Quinet E, Vickerman R (eds) Handbook of transport economics. Edward Elgar, pp 97–115Behar A, Manners P, Nelson B (2009) Exports and logistics. Oxford Department of Economics Discussion Paper 439Bergstrand JH (1985) The gravity equation in international trade: some microeconomic foundations and empirical evidence. Rev Econ Stat 71: 143–153. http://www.jstor.org/stable/1925975Bergstrand JH (1989) The generalized gravity equation, monopolistic competition, and the factor-proportions theory in international trade. Rev Econ Stat 67: 474–481. http://www.jstor.org/stable/1928061Breuss F, Egger P (1999) How reliable are estimations of east-west trade potencials based on cross-section gravity analysis? Empirica 26:86–89. doi: 10.1023/A:1007011329676CILT (2012) Available at http://www.ciltuk.org.uk/pages/royalcharter . Accessed 02 Aug 2012Felipe J, Kumar U (2012) The role of trade facilitation in Central Asia: a gravity model. East Eur Econ 50:5–20. doi: 10.2753/EEE0012-875500401Heckman J (1979) Sample selection bias as a specification error. Econometrica 47: 153–161. http://www.jstor.org/stable/1912352Helpman E, Krugman P (1985) Market structure and foreign trade. Increasing returns, imperfect competition and the international economy. The MIT Press, Cambridge, MA/LondonHertel T, Mirza T (2009) The role of trade facilitation in South Asian economic integration. Study on intraregional trade and investment in South Asia. ADB, Mandaluyong CityHollweg C, Wong M-H (2009) Measuring regulatory restrictions in logistics services. ERIA Discussion Paper Series, no. 14Jane C–C (2011) Performance evaluation of logistic systems under cost and reliability considerations. Transp Res E-Log 47:130–137. doi: 10.1016/j.tre.2010.09.012Keskin MH (2012) The exigencies of the common logistics policy for European community and the deconstruction of the common transportation policy. Afr J Bus Manage 6:10697–10707. doi: 10.5897/AJBM11.1523Korinek J, Sourdin P (2011) To what extent are high-quality logistics services trade facilitating? Oecd trade policy working papers 108. OECD PublishingLangley C, Coyle J, Gibson B, Novak R, Bardi E (2008) Managing supply chain: a logistics approach. South–Western College Publishing, LondonMangan J, Lalwani C, Butcher C (2008) Global logistics and supply chain management. Wiley John & Sons, Inc., Hoboken, NJMartí ML, Puertas R, García L (2012) Relevance of trade facilitation in emerging countries′s export. J Int Trade Eco Dev. http://www.tandfonline.com/doi/abs/10.1080/09638199.2012.698639Requena F, Llano C (2010) The border effects in Spain: an industrial-level analysis. Empirica 37:455–476. doi: 10.1007/s10663-010-9123-6Rushton A, Oxley J, Croucher P (2009) The handbook of logistics and distribution management. Kogan Page, LondonVilko J, Karandassov B, Myller E (2011) Logistic infrastructure and its effects on economic development. China–USA Bus Rev 10:1152–1167World Bank (2010) Trade and transport facilitation assessment: a practical toolkit for country implementation. World Bank, Washingto

Vortices in polariton OPO superfluids

This chapter reviews the occurrence of quantised vortices in polariton fluids, primarily when polaritons are driven in the optical parametric oscillator (OPO) regime. We first review the OPO physics, together with both its analytical and numerical modelling, the latter being necessary for the description of finite size systems. Pattern formation is typical in systems driven away from equilibrium. Similarly, we find that uniform OPO solutions can be unstable to the spontaneous formation of quantised vortices. However, metastable vortices can only be injected externally into an otherwise stable symmetric state, and their persistence is due to the OPO superfluid properties. We discuss how the currents charactering an OPO play a crucial role in the occurrence and dynamics of both metastable and spontaneous vortices.Comment: 40 pages, 16 figure