Dirac-Born-Infeld actions and Tachyon Monopoles

We investigate magnetic monopole solutions of the non-abelian DBI action describing 2 coincident non-BPS D9-branes in flat space. Just as in the case of kink and vortex solitonic tachyon solutions of the full DBI non-BPS actions, as previously analyzed by Sen, these monopole configurations are singular in the first instance and require regularization. We discuss a suitable non-abelian ansatz and show it solves the equations of motion to leading order in the regularization parameter. Fluctuations are studied and shown to describe a codimension 3 BPS D6-brane. A formula is derived for its tension. We comment on the implication to our results from both the trace (Tr) and symmetrized trace (Str) prescriptions of the non-abelian DBI action of coincident non-BPS D9-branes.Comment: 17 pages, jhep3.cl

An unexpected complication of a percutaneous coronary angioplasty

Takotsubo cardiomyopathy (TCM) is characterized by transient ventricular dysfunction, classically in its apical and mid segments in the absence of coronary lesions, and is often observed after intense stressful events and occasionally associated to an acute medical illness. We describe a case of TCM associated with coronary artery disease and triggered by a percutaneous coronary angioplasty. This case highlights the concept that a medical procedure can lead, in certain conditions, to TCM and provides new interesting insights on the pathophysiology of coronary syndromes

Fabbricazione di microstrutture free-standing in silicio cristallino mediante attacco elettrochimico

Il principale scopo di questo lavoro di tesi è quello di sviluppare una nuova metodologia di fabbricazione di microstrutture free-standing in silicio cristallino utilizzando una tecnologia a basso costo, il micromachining elettrochimico, rispetto alle tecniche oggi impiegate per la fabbricazione di strutture MEMS. Dopo aver esaminato i vantaggi e gli svantaggi delle moderne tecniche di fabbricazione e le principali applicazioni dei MEMS, rispettivamente nel primo e nel secondo capitolo, nel terzo capitolo verrà analizzata in dettaglio la tecnica del micromachining elettrochimico del silicio (attacco da fase liquida del silicio in soluzione a base di acido fluoridrico). Nel quarto capitolo, infine, dopo aver presentato la metodologia di fabbricazione di microstrutture free-standing in silicio cristallino mediante micromachining elettrochimico, verranno illustrati in dettaglio il processo di fabbricazione e i risultati sperimentali ottenuti

ICT and tourism impacts in islands

New technologies can represent, for some aspects, both a problem and a precious resource. As we concerns, in tourism sector, ICT can help in managing and promoting destinations in a better way than in the past, especially in those cases where problems linked with the management of tourist flows and the need to manage a sustainable development exists. Monitoring tourism impact at the destination is a fundamental issue in order to respect the right pressure and to avoid negative effects in the destination and with the residents. There are several devices available and useful for different needs, then almost each kind of monitoring and analysis can be supported by the right tools. This knowledge should encourage local responsible to implement regular and meticulous surveys and analysis to manage the impact of tourism pressure and to respect the optimal carrying capacity of the site

Relationship between NOX4 level and angiotensin II signaling in Gitelman's syndrome. Implications with hypertension

Recent evidence showed that endogenous nicotinamide adenine dinucleotide phosphate-oxidase 4 (NOX4) may exert a protective role on the cardiovascular system inducing vasodilation, reduction of blood pressure, and anti-proliferative actions. However, the functional significance of NOX4 in the cardiovascular system in humans remains elusive. Mononuclear cell levels of NOX4 were assessed by immunoblotting in 14 Gitelman's patients (GS), a unique human model of endogenous Ang II signaling antagonism and activation of anti-atherosclerotic and anti-remodeling defenses, and compared to 11 untreated essential hypertensive patients as well as to 11 healthy normotensive subjects. The association between NOX4 and its effector heme oxygenase (HO-1) (sandwich immunoassay) was also evaluated. NOX4 protein levels were decreased in hypertensive patients as compared to both GS and healthy subjects (1.06±0.31 AU vs. 1.76±0.54, P=0.002 and vs. 1.61±0.54, P=0.018, respectively). NOX4 protein level did not differ between GS and healthy subjects. HO-1 levels were increased in GS patients as compared to both hypertensive patients and healthy subjects (8.65±3.08 ng/ml vs 3.70±1.19, P<0.0001, and vs 5.49±1.04, P=0.008, respectively. NOX4 levels correlate with HO-1 levels only in GS (r(2)=0.63; P=0.001), (r(2)=0.088; P=ns, in hypertensive patients and r(2)=0.082; P=ns, in healthy subjects). Our findings show that NOX4 and its effector HO-1 are reduced in hypertensive patients compared to GS patients, a human model opposite to hypertension. Although the functional significance of NOX4 needs further clarification, our preliminary data in a unique human model of anti-atherosclerotic and anti-remodeling defenses activation, highlight the potentially protective role of NOX4 in the human cardiovascular system

Tourism Dynamics and Sustainability: A Comparative Analysis between Mediterranean Islands: Evidence for Post-COVID-19 Strategies

Tourism may not sustainably support territories with limited natural resource stock such as islands. The volume of visitor arrivals and the industry investments can increase the pressure even beyond sustainable levels. There is an evident and unresolved tension between these two great polarities, sustainability and economic growth driven by tourism. The aim for policymakers is to find an acceptable equilibrium between these two dimensions. This paper investigates tourism evo- lution between 2007 and 2019 in 15 Mediterranean islands, comparing tourism pressures through statistical indicators. The analysis will compare tourism demand and supply trends in these con- texts. The performances will be evaluated to identify the islands’ positioning between sustainability needs and tourism development opportunities while considering post-COVID-19 challenges

Governing the zoo

In this chapter we examine the alternative approaches to governing the zoo in Italy and England – two countries with long traditions of state support for social enterprise. Italy is widely credited with developing the concept of social enterprise, and was one of the first countries in the world to develop a specific legal form for social enterprise through the social cooperative, while England has arguably the most developed state support apparatus for social enterprise. Despite different political starting points, and different approaches to governing the zoo, both Italy and England appear to be converging towards a governance model whereby organizational form is downplayed in favour of more instrumental approaches in which political support is provided to any organization or activity that can contribute towards policy goals. This promises a social enterprise zoo with greater biodiversity in both countries

Phase Transitions in Separated Dp−1D_{p-1} and anti-Dp−1D_{p-1} Branes at Finite Temperature

We consider a pair of parallel ${\rm D}_{p-1}$ and anti-${\rm D}_{p-1}$ branes in flat space, with a finite separation $d$ along some perpendicular spatial direction and at finite temperature. If this spatial direction is compactified on a circle then by T-duality, the system is equivalent to a ${\rm D}_{p}$-anti ${\rm D}_{p}$ pair wrapped around the dual circle with a constant Wilson line $A \approx d$ on one of the branes. We focus in particular on the $p=9$ case and compute the free energy of this system and study the occurrence of second order phase transitions as both the temperature and Wilson line (brane-antibrane separation) are varied. In the limit of vanishing Wilson line we recover the previous results obtained in the literature, whereby the open string vacuum at the origin of the tachyon field T=0 is stabilized at sufficiently high temperature at which a second order phase transition occurs. For sufficiently large Wilson line, we find new second order phase transitions corresponding to the existence of two minima in the tachyon effective potential at finite temperature and tachyon field value. Entropic arguments suggest that as the system cools, the tachyon is likely to find itself in the minimum that approaches infinity as the temperature vanishes (i.e. the one corresponding to the closed string vacuum), rather than the minimum at T=0 (corresponding to the open string vacuum).Comment: 25 pages, 4 figures; Clarifications added to Section 3 concerning winding modes; updated plots of the effective potential in section 4; typos corrected. Version to be published in JHE