Nonlinear aeroelastic modeling via conformal mapping and vortex method for a flat-plate airfoil in arbitrary motion

A nonlinear aerodynamic modeling based on conformal mapping is presented to obtain semi-analytical formulas for the unsteady aerodynamic force and pitching moment on a flat-plate airfoil in arbitrary motion. The aerodynamic model accounts for large amplitudes and non-planar wake and is used to study the aeroelastic behavior of a flat-plate airfoil elastically connected to a support. The fluid is assumed to be inviscid and incompressible, while the flow is assumed to be attached, planar, and potential. Within these hypotheses, conformal mapping and a complex-potential representation of unsteady aerodynamics are used to simplify the theoretical formulation. The vorticity shed at the trailing edge is discretized in desingularized point vortices in order to allow free-wake dynamics. The unsteady aerodynamic model is validated with classical linearized formulations based on the assumption of small disturbances, and with experimental data and theoretical predictions for a large-amplitude pitch-up, hold, pitch-down maneuver. The aeroelastic model is then used to simulate the response of a flat-plate airfoil to sudden starts and body-vortex interactions. Numerical results show that the proposed approach can be an effective tool to model the aeroelastic behavior of an arbitrarily-moving wing section in a time-dependent potential stream of incompressible fluid

Spectral control for ecological stability

A system made up of N interacting species is considered. Self-reaction terms are assumed of the logistic type. Pairwise interactions take place among species according to different modalities, thus yielding a complex asymmetric disordered graph. A mathematical procedure is introduced and tested to stabilise the ecosystem via an {\it ad hoc} rewiring of the underlying couplings. The method implements minimal modifications to the spectrum of the Jacobian matrix which sets the stability of the fixed point and traces these changes back to species-species interactions. Resilience of the equilibrium state appear to be favoured by predator-prey interactions

Multinational Banking in Europe: Financial Stability and Regulatory Implications. Lessons from the Financial Crisis

This paper examines whether multinational banks have a stabilising or a destabilising role during times of financial distress. With a focus on Europe, it looks at how these banks‟ foreign affiliates have been faring during the recent financial crisis. It finds that retail and corporate lending of these foreign affiliates have been stable and even increasing between 2007 and 2009. This pattern is related to the functioning of the internal capital market through which these banks funnel funds across their units. The internal capital market has been an effective tool to support foreign affiliates in distress and to isolate their lending from the local availability of financial resources, notwithstanding the systemic nature of the recent crisis. This effect has been particularly large within the EU integrated financial market and for the EMU countries, thus showing complementarity between economic integration and multinational banks‟ internal capital markets. In light of these findings, this paper supports the call for an integration of the European supervisory and regulatory framework overseeing multinational banks. The analysis is based on an analytical framework which derives the main conditions under which the internal capital market can perform this support function under idiosyncratic and systemic stresses. The empirical evidence uses both aggregate evidence on foreign claims worldwide, and firm-level evidence on the behaviour of banking groups‟ affiliates, compared to standing alone national banks.multinational banking, financial stability, regulation and supervision, internal capital markets, financial crises

Adipose stromal cells promote the transition of colorectal cancer cells toward a mesenchymal-like phenotype

Colon cancer progression is among the risks that increase with obesity. We have recently unveiled the molecular mechanism by which adipose tissue-released molecules, HGF and IL-6, make colorectal cancer (CRC) cells acquiring mesenchymal traits. Targeting of adipose-derived factors abrogate the metastatic potential of CRC stem cells (CR-CSCs) in obese patients

Global topological control for synchronized dynamics on networks

A general scheme is proposed and tested to control the symmetry breaking instability of a homogeneous solution of a spatially extended multispecies model, defined on a network. The inherent discreteness of the space makes it possible to act on the topology of the inter-nodes contacts to achieve the desired degree of stabilization, without altering the dynamical parameters of the model. Both symmetric and asymmetric couplings are considered. In this latter setting the web of contacts is assumed to be balanced, for the homogeneous equilibrium to exist. The performance of the proposed method are assessed, assuming the Complex Ginzburg-Landau equation as a reference model. In this case, the implemented control allows one to stabilize the synchronous limit cycle, hence time-dependent, uniform solution. A system of coupled real Ginzburg-Landau equations is also investigated to obtain the topological stabilization of a homogeneous and constant fixed point

The growing interest in vitamin D is positively related to that of its kidney complications and is negatively related to that of bone benefit: an analysis based on Google Trends (Preprint)

Background. The benefits of vitamin D relate to muscle strength, cardiovascular health, and prevents osteoporosis. Objective. This study aimed to explore trends of global interest on vitamin D, hypercalcaemia, adverse kidney effects (stones and kidney failure) and osteoporosis. Methods. An electronic search was conducted with Google Trends, limiting searches based on the "health" criterion. Results. Worldwide interest in vitamin D3 (cholecalciferol), vitamin D2 (ergocalciferol or calciferol), kidney stones and kidney failure is progressively growing over time. On the other hand, vitamin D was found to be negatively correlated with hypercalcaemia and bone density. Another result of our analysis is the distribution of the popularity of searches across countries. In particular, the global popularity for vitamin D3 seems higher than that of vitamin D2 and also shows different geographical preferences. The growing interest in vitamin D parallels that of kidney stones and kidney failure, while decreasing popularity has been noted for hypercalcaemia and bone density. Conclusions. The research volumes help to clarify the changes in the trends of use of supplements and the development of their complications, according to the different geographical areas, socioeconomic status and online literac

DNA and BSA Interaction Studies and Antileukemic Evaluation of Polyaromatic Thiosemicarbazones and Their Copper Complexes

Some ten million cancer deaths occurred in 2020, highlighting the fact that the search for new anticancer drugs remains extremely topical. In the search for new coordination compounds with relevant biological properties, the choice of a metal ion is important for the design of the complex. In this regard, copper plays a peculiar role, thanks to its distinct properties. Thiosemicarbazones are, analogously, a unique class of ligands because they are easily modifiable, and therefore, extremely versatile in terms of modulating molecular properties. In this work, we synthesized and characterized, by means of X-ray diffraction, four new naphthaldehyde and anthraldehyde thiosemicarbazone derivatives and their copper complexes to be used in interaction studies with biological systems. The objective was to evaluate the antileukemic activity of these compounds. Reactions of these ligands with Cu(II) salts produced unexpected oxidation products and the isolation of Cu(I) metal complexes. One ligand and its related Cu(I) complex, which is stable in physiological conditions, were subjected to in vitro biological tests (UV-Vis and CD titration). An important interaction with DNA and an affinity toward BSA were observed in FT-IR experiments. Preliminary in vitro biological tests against a histiocytic lymphoma cell line revealed an interestingly low IC50 value, i.e., 5.46 µM, for the Cu(I) comple

Chronic Knee and Ankle Pain Treatment through Selective Microsurgical Approaches: A Minimally Invasive Option in the Treatment Algorithm for Refractory Lower Limb Pain

 Injury or compression of a sensory nerve is an under-reported source of disabling pain in the lower limb. It is known that peripheral nerve microsurgeons can reconstruct and rewire injured nerves to relieve chronic pain but this option remains not completely understood and ignored by most orthopaedic surgeons, neurologists, and pain therapists. In this paper, we describe our experience with knee and ankle peripheral nerve surgery to improve the condition of patients suffering from chronic, posttraumatic lower limb pain