Interference in interacting quantum dots with spin

We study spectral and transport properties of interacting quantum dots with spin. Two particular model systems are investigated: Lateral multilevel and two parallel quantum dots. In both cases different paths through the system can give rise to interference. We demonstrate that this strengthens the multilevel Kondo effect for which a simple two-stage mechanism is proposed. In parallel dots we show under which conditions the peak of an interference-induced orbital Kondo effect can be split.Comment: 8 pages, 8 figure

Recognition and Assessment of Geomorphosites in Malta at the Il-Majjistral Nature and History Park

The Il-Majjistral Nature and History Park, located on the northwestern coast of the Island of Malta, is a protected area with natural, cultural and tourist interests. The Park, which was registered in 2008, is characterised by a landscape dominated by limestone and clay. Geomorphological features are highly controlled by the presence of faults and rock masses characterised by different physical and mechanical properties. Coastal cliffs, bays and sandy beaches are the most outstanding geomorphological features of the Park, creating a breathtaking landscape which is an attraction for a number of visitors. In the framework of an international research project, a study for the identification, selection and enhancement of the rich geomorphological heritage of the area has been carried out. In particular, a recognition and a quantitative assessment of geomorphosites on the basis of two different methodologies has been developed, and the results have been compared to establish the reliability of the methodologies. The results represent the first step and the necessary basic knowledge for possible enhancement of geomorphosites in Malta and the promotion of tourism activities at the Il-Majjistral Nature and History Park through the auspices of environmental agencies

Advanced SAR interferometric analysis to support geomorphological interpretation of slow-moving coastal landslides (Malta, Mediterranean Sea)

An advanced SAR interferometric analysis has been combined with a methodology for the automatic classification of radar reflectors phase histories to interpret slope-failure kinematics and trend of displacements of slow-moving landslides. To accomplish this goal, the large dataset of radar images, acquired in more than 20 years by the two European Space Agency (ESA) missions ERS-1/2 and ENVISAT, was exploited. The analysis was performed over the northern sector of Island of Malta (central Mediterranean Sea), where extensive landslides occur. The study was assisted by field surveys and with the analysis of existing thematic maps and landslide inventories. The outcomes allowed definition of a model capable of describing the geomorphological evolution of slow-moving landslides, providing a key for interpreting such phenomena that, due to their slowness, are usually scarcely investigated

BCKDH: the missing link in apicomplexan mitochondrial metabolism is required for full virulence of Toxoplasma gondii and Plasmodium berghei

While the apicomplexan parasites Plasmodium falciparum and Toxoplasma gondii are thought to primarily depend on glycolysis for ATP synthesis, recent studies have shown that they can fully catabolize glucose in a canonical TCA cycle. However, these parasites lack a mitochondrial isoform of pyruvate dehydrogenase and the identity of the enzyme that catalyses the conversion of pyruvate to acetyl-CoA remains enigmatic. Here we demonstrate that the mitochondrial branched chain ketoacid dehydrogenase (BCKDH) complex is the missing link, functionally replacing mitochondrial PDH in both T. gondii and P. berghei. Deletion of the E1a subunit of T. gondii and P. berghei BCKDH significantly impacted on intracellular growth and virulence of both parasites. Interestingly, disruption of the P. berghei E1a restricted parasite development to reticulocytes only and completely prevented maturation of oocysts during mosquito transmission. Overall this study highlights the importance of the molecular adaptation of BCKDH in this important class of pathogens

Horizontal partial laryngectomy for supraglottic squamous cell carcinoma

Between 1981-1999, 75 patients treated for supraglottic SCC with horizontal supraglottic laryngectomy (HSL) at the Otolaryngology Head and Neck Surgery Department of Lausanne University Hospital were retrospectively studied. There were 16 patients with T1, 46 with T2 and 13 with T3 tumors. Among these, 16 patients (21%) had clinical neck disease corresponding to stage I, II, III and IV in 12, 39, 18 and 6 patients, respectively. All patients had HSL. Most patients had either elective or therapeutic bilateral level II-IV selective neck dissection. Six patients (8%) with advanced neck disease had ipsilateral radical and controlateral elective II-IV selective neck dissections. Adjuvant radiotherapy was given to 25 patients (30%) for either positive surgical margins (n=8), pathological nodal status (n=14) or both (n=3). Median follow-up was 48months (range, 24-199). Five-year disease-specific survival and locoregional and local control were 92, 90 and 92.5%, respectively. Among five patients who were diagnosed with local recurrence, one had a total laryngectomy (1.4%); the others were treated by endoscopic laser surgery. Two patients had both a local and regional recurrence. They were salvaged with combined surgery and radiotherapy, but eventually died of their disease. Cartilage infiltration seems to influence both local control (P=0.03) and disease-specific survival (P=0.06). There was a trend for worse survival with pathological node involvement (P=0.15) and extralaryngeal extension of the cancer (P=0.1). All patients except one recovered a close to normal function after the treatment. Aspiration was present in 16 patients (26%) in the early postoperative period. A median of 16days (7-9) was necessary to recover a close to normal diet. Decannulation took a median of 17days (8-93). Seven patients kept a tracheotomy tube for up to 3months because of persistent aspiration. There was no permanent tracheostomy or total laryngectomy for functional purposes. Horizontal supraglottic laryngectomy remains an adequate therapeutic alternative for supraglottic squamous cell carcinoma, offering an excellent oncological outcome. The postoperative functional morbidity is substantial, indicating the need for careful patient selection, but good laryngeal function recovery is the rule. The surgical alternative is endoscopic laser surgery, which may offer comparable oncological results with less functional morbidity. Nevertheless, these two different techniques need to be compared prospectivel

Landslide susceptibility modeling assisted by Persistent Scatterers Interferometry (PSI): an example from the northwestern coast of Malta

Persistent Scatterers Interferometry (PSI) techniques are widely employed in geosciences to detect and monitor landslides with high accuracy over large areas, but they also suffer from physical and technological constraints that restrict their field of application. These limitations prevent us from collecting information from several critical areas within the investigated region. In this paper, we present a novel approach that exploits the results of PSI analysis for the implementation of a statistical model for landslide susceptibility. The attempt is to identify active mass movements by means of PSI and to avoid, as input data, time-/cost-consuming and seldom updated landslide inventories. The study has been performed along the northwestern coast of Malta (central Mediterranean Sea), where the peculiar geological and geomorphological settings favor the occurrence of a series of extensive slow-moving landslides. Most of these consist in rock spreads, evolving into block slides, with large limestone blocks characterized by scarce vegetation and proper inclination, which represent suitable natural radar reflectors for applying PSI. Based on geomorphometric analyses and geomorphological investigations, a series of landslide predisposing factors were selected and a susceptibility map created. The result was validated by means of cross-validation technique, field surveys and global navigation satellite system in situ monitoring activities. The final outcome shows a good reliability and could represent an adequate response to the increasing demand for effective and lowcost tools for landslide susceptibility assessment

The quantum Hall effect in graphene samples and the relativistic Dirac effective action

We study the Euclidean effective action per unit area and the charge density for a Dirac field in a two--dimensional spatial region, in the presence of a uniform magnetic field perpendicular to the 2D--plane, at finite temperature and density. In the limit of zero temperature we reproduce, after performing an adequate Lorentz boost, the Hall conductivity measured for different kinds of graphene samples, depending upon the phase choice in the fermionic determinant.Comment: Conclusions extended. References added. 9 pages. 1 figur

Geositi nel paesaggio mediterraneo: confronto tra aree costiere maltesi e siciliane.

Le isole maltesi mostrano aspetti geologici, geomorfologici e ambientali comparabili con quelli siciliani che danno luogo alla presenza di elementi paesaggistici ad elevata potenzialit\ue0 turistica, ad oggi non sufficientemente valorizzati. Nell\u2019ambito di un progetto di ricerca internazionale volto alla realizzazione di reti ecologiche transfrontaliere Malta-Sicilia (RE.MA.SI.), sono stati condotti studi sulla valorizzazione, divulgazione e corretta fruizione del patrimonio geologico di alcuni territori di queste due isole. Vengono qui presentati i risultati preliminari che hanno portato all'identificazione e valorizzazione di geositi di interesse geomorfologico, le cui caratteristiche sono state analizzate qualitativamente e quantitativamente, tramite l\u2019applicazione di metodologie gi\ue0 sperimentate a livello internazionale e basate sulla stima del loro valore scientifico, addizionale e di fruibilit\ue0. Sono state analizzate principalmente forme di rilevante interesse scientifico, didattico e paesaggistico, quali morfotipi costieri, evidenze morfologiche di processi gravitativi e di erosione idrica e forme carsiche

On the scattering amplitude in the Aharonov-Bohm gauge field

A general expression for the scattering amplitude of nonrelativistic spinless particles in the Aharonov-Bohm gauge potential is obtained within the time independent formalism. The result is valid also in the backward and forward directions as well as for any choice of the boundary conditions on the wave function at the flux tube position.Comment: 18 pages, plain TE