Solar dynamo model with nonlocal alpha-effect

The first results of the solar dynamo model that allows for the diamagnetic effect of inhomogeneous turbulence and the nonlocal alpha-effect due to the rise of magnetic loops are discussed. The nonlocal alpha-effect is not subject to the catastrophic quenching related to the conservation of magnetic helicity. Given the diamagnetic pumping, the magnetic fields are concentrated near the base of the convection zone, although the distributed-type model covers the entire thickness of the convection zone. The magnetic cycle period, the equatorial symmetry of the field, its meridional drift, and the polar-to-toroidal field ratio obtained in the model are in agreement with observations. There is also some disagreement with observations pointing the ways of improving the model.Comment: To appear in Astronomy Letters, 10 pages, 5 figure

Cosmology of neutrinos and extra light particles after WMAP3

We study how present data probe standard and non-standard properties of neutrinos and the possible existence of new light particles, freely-streaming or interacting, among themselves or with neutrinos. Our results include: sum m_nu < 0.40 eV at 99.9% C.L.; that extra massless particles have abundance Delta N_nu = 2 pm 1 if freely-streaming and Delta N_nu = 0 pm 1.3 if interacting; that 3 interacting neutrinos are disfavored at about 4 sigma. We investigate the robustness of our results by fitting to different sub-sets of data. We developed our own cosmological computational tools, somewhat different from the standard ones.Comment: 18 pages, 8 figures. Added in v2: an explicit comparison of our code with CAMB, some clarifications on the statistical analysis and some references. Matches version published in JCA

Simulation of the Three-Dimensional Hinge Flow Fields of a Bileaflet Mechanical Heart Valve Under Aortic Conditions

Thromboembolic complications of bileaflet mechanical heart valves (BMHV) are believed to be due to detrimental stresses imposed on blood elements by the hinge flows. Characterization of these flows is thus crucial to identify the underlying causes for complications. In this study, we conduct three-dimensional pulsatile flow simulations through the hinge of a BMHV under aortic conditions. Hinge and leaflet geometries are reconstructed from the Micro-Computed Tomography scans of a BMHV. Simulations are conducted using a Cartesian sharp-interface immersed-boundary methodology combined with a second-order accurate fractional-step method. Physiologic flow boundary conditions and leaflet motion are extracted from the Fluid–Structure Interaction simulations of the bulk of the flow through a BMHV. Calculations reveal the presence, throughout the cardiac cycle, of flow patterns known to be detrimental to blood elements. Flow fields are characterized by: (1) complex systolic flows, with rotating structures and slow reverse flow pattern, and (2) two strong diastolic leakage jets accompanied by fast reverse flow at the hinge bottom. Elevated shear stresses, up to 1920 dyn/cm2 during systole and 6115 dyn/cm2 during diastole, are reported. This study underscores the need to conduct three-dimensional simulations throughout the cardiac cycle to fully characterize the complexity and thromboembolic potential of the hinge flows

Numerical comparison of the closing dynamics of a new trileaflet and a bileaflet mechanical aortic heart valve

[[abstract]]The closing velocity of the leaflets of mechanical heart valves is excessively rapid and can cause the cavitation phenomenon. Cavitation bubbles collapse and produce high pressure which then damages red blood cells and platelets. The closure mechanism of the trileaflet valve uses the vortices in the aortic sinus to help close the leaflets, which differs from that of the monoleaflet or bileaflet mechanical heart valves which mainly depends on the reverse flow. We used the commercial software program Fluent to run numerical simulations of the St. Jude Medical bileaflet valve and a new trileaflet mechanical heart valve. The results of these numerical simulations were validated with flow field experiments. The closing velocity of the trileaflet valve was clearly slower than that of the St. Jude Medical bileaflet valve, which would effectively reduce the occurrence of cavitation. The findings of this study are expected to advance the development of the trileaflet valve.[[incitationindex]]SCI[[booktype]]電子版[[booktype]]紙

RNAi for Treating Hepatitis B Viral Infection

Chronic hepatitis B virus (HBV) infection is one of the leading causes of liver cirrhosis and hepatocellular carcinoma (HCC). Current treatment strategies of HBV infection including the use of interferon (IFN)-α and nucleotide analogues such as lamivudine and adefovir have met with only partial success. Therefore, it is necessary to develop more effective antiviral therapies that can clear HBV infection with fewer side effects. RNA interference (RNAi), by which a small interfering RNA (siRNA) induces the gene silence at a post-transcriptional level, has the potential of treating HBV infection. The successful use of chemically synthesized siRNA, endogenous expression of small hairpin RNA (shRNA) or microRNA (miRNA) to silence the target gene make this technology towards a potentially rational therapeutics for HBV infection. However, several challenges including poor siRNA stability, inefficient cellular uptake, widespread biodistribution and non-specific effects need to be overcome. In this review, we discuss several strategies for improving the anti-HBV therapeutic efficacy of siRNAs, while avoiding their off-target effects and immunostimulation. There is an in-depth discussion on the (1) mechanisms of RNAi, (2) methods for siRNA/shRNA production, (3) barriers to RNAi-based therapies, and (4) delivery strategies of siRNA for treating HBV infection

ESPON Italian evidence in changing Europe

Il volume, che rientra nelle attività dell’ESPON Contact Point Italia, accoglie i risultati del contributo dei Partner Italiani allo sviluppo dei progetti del Programma ESPON 2013, acronimo di European Observation Network for Territorial Development and Cohesion. I testi sintetizzano ed evidenziano, tra l’altro, le relazioni con le politiche di sviluppo regionale dell’Italia, inserendole in un quadro di cooperazione transnazionale che coinvolge 28 + 4 paesi dell’Unione europea. Affrontando aspetti della politica territoriale europea che spaziano dall’innovazione e conoscenza all’accessibilità, dal policentrismo alle aree metropolitane, dalla migrazione alla globalizzazione, gli Autori mettono in luce la posizione dell’Italia e delle regioni anche rispetto agli obiettivi fissati da Europe 2020. Uno spazio è dedicato alle esperienze regionali che hanno trovato in ESPON uno stimolo e un’occasione di confronto; come pure ai concetti che sottendono il lessico, i principi di orientamento e i nuovi modelli della pianificazione in Europa; e alle esperienze formative rivolte alle giovani generazioni e ai decision maker Il libro si inquadra nelle iniziative del Semestre di Presidenza Italiana dell’Unione europea ed è cofinanziato dal Ministero delle Infrastrutture e dei Trasporti (MIT) responsabile nazionale del Programma ESPON. E’ rivolto ai ricercatori, agli utilizzatori istituzionali, ai policy maker, ai “practioner” e ai “non specialisti”, tra cui gli studenti, affinché possano fare propri i risultati dell’impegno costante, rigoroso e rispettoso delle diversità territoriali che hanno contraddistinto, dal 2007 ad oggi, il contributo della ricerca, anche sperimentale e applicata, alla crescita della società italiana come parte integrante del sistema europeo. L’Osservatorio ESPON, per chi ancora non lo conosce, può rappresentare un viaggio nel territorio europeo, nelle sue diversità territoriali, economiche, sociali, culturali da integrare e rendere coese, sostenibili, mantenendo e sviluppando potenziali di competitività crescenti e, nel contempo, innovando e diffondendo nuovi modi, metodologie, strumenti e prassi per fare del territorio un bene comune e condiviso. Dati, riferimenti e raccomandazioni politiche utili alla crescita del Paese completano il quadro. Presentazione del Ministro delle Infrastrutture, On. Maurizio Lupi Postfazione del Direttore della Coordination Unit del Programma ESPON, Peter MehlbyeThe book is part of the activities of ESPON Contact Point Italy. It includes the results of the contribution of the Italian partners in the development of projects under the ESPON 2013 Programme, which stands for European Observation Network for Territorial Development and Cohesion. The texts summarise and highlight, among other things, the relations with the regional development policies of Italy, placing them in a framework of transnational cooperation involving the 28 + 4 EU Countries. Addressing aspects of European territorial policy, ranging from innovation and knowledge accessibility, from the polycentrism to metropolitan areas, from migration to globalization, the authors highlight the position of Italy and of regions also in relation to the objectives set by Europe 2020. A place is devoted to the regional experiences that in the ESPON found a stimulus and an opportunity for discussion, as well as to the concepts behind the vocabulary, to the principles of guidance, and new planning models in Europe, and to the training experiences aimed at the younger generations and the decision makers The book forms part of the initiatives of the Italian Presidency of the European Union and is co-financed by the Ministry of Infrastructure and Transportation (MIT) in charge of the national ESPON Programme. It is aimed at researchers, institutional users, policy makers, at "practitioners" and "non-specialists" including students, so that they can make use of the results of the constant and rigorous work also respectful of the territorial diversities that have characterized the experimental and applied research since 2007, so contributing to the growth of Italian society as an integral part of the European system. The ESPON Monitoring Centre, for those who still do not know, can be a journey into the European territory, its territorial, economic, social, cultural diversities to integrate and make cohesive and sustainable, by maintaining and developing the increasing potentials of competitiveness and, at the same time, by innovating and disseminating new ways, methodologies, tools and practices to make the territory a common and shared good. Data, references and useful policy recommendations to the growth of the country are also included in the book. Presentation by the Minister of Infrastructure, Mr. Maurizio Lupi Afterword by the Director of the Coordination Unit ESPON Programme , Peter Mehlby

Meromixis origin and recent trophic evolution in the Spanish mountain lake La Cruz

A sediment core from a Mediterranean karstic lake was studied through its pollen, diatom, chydorid, ostracod, charcoal and authigenic mineral composition. Information about environmental history recorded in the sediment sequence since the Middle Ages is presented. The main fluctuations of water volume and trophic status of the lake occurred during periods of great change in land management and during climatic cold phases. The synergetic effect of these two factors led to a high water level phase and triggered a rising of the trophic level which produced meromixis. The onset of meromictic conditions at about 1700 AD coincides with the Maunder minimum in the Little Ice Age as well as with a period of increasing human population, woodland clearance and agricultural expansion to the detriment of the nomadic livestock-breeding or transhumance ("Mesta")