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The problem of imposing the reference conditions in a floating frame of reference formulation is coupled with the necessity to reduce the interfaces to virtual nodes required to define the multibody joints. Two methods are implemented for rigid and interpolation multipoint constraints, and the reference condition matrix is derived employing all the interface dofs. The case study of a slider-crank mechanism is discussed to show how different sets of reference conditions can modify the system’s dynamics.

Large Deployable Reflector (LDR) systems are commonly used as mesh reflectors for large aperture space antennas in aerospace applications since they provide affordability while guaranteeing at the same time a high gain and a high directivity. To improve the surface accuracy several methods have been studied, most of which measure the distance between the cable-net system that forms the reflector surface and the desired paraboloid. In this paper we want to improve the reflector’s ability to convey a greater concentration of reflected rays in the direction of the feed. To deal with this issue, a numerical optimization algorithm has been proposed.

Il canale tra le isole di Sicilia e Malta si trova in una delle principali rotte marittime del Mediterraneo e in una regione strategica per le piattaforme di estrazione petrolifera, quindi seriamente esposta al rischio di eventi di sversamento di idrocarburi in mare. Ciò può costituire una grave minaccia agli ecosistemi locali e alle attività economiche, tra le quali il turismo e la pesca. I danni derivanti da un eventuale sversamento sarebbero incalcolabili per l'arcipelago maltese, dove le risorse marine ed il turismo rappresentano i principali proventi economici e, in maniera analoga, per la Sicilia. Le misure di prevenzione e di mitigazione, insieme a un rapido intervento e a un processo decisionale stabile e solido in caso di situazioni di emergenza, aiutano a minimizzare i rischi e a ridurre gli impatti. Grazie alla tecnologia radar ad alta frequenza (HF), la rete CALYPSO rappresenta lo strumento essenziale per il monitoraggio delle correnti superficiali del mare in tempo reale. La tecnologia radar HF fornisce uno strumento unico per determinare le correnti superficiali in tempo 'quasi' reale, consentendo l’applicazione efficace di modelli numerici di dispersione d’inquinanti in mare. Tale metodologia permette di prevedere origine e destinazione dell’inquinante attraverso l'assimilazione dei dati nei modelli di circolazione oceanica, o tramite previsioni statistiche delle correnti marine a breve termine. La rete CALYPSO, operativa da agosto 2012, è attualmente costituita da quattro sistemi SeaSonde (CODAR) che funzionano nella banda di frequenza dei 13.5 MHz. Le misure ottenute sono state ampiamente validate utilizzando sia correntometri che drifters che hanno ripetutamente fornito prove evidenti dell'affidabilità dei dati acquisiti. Le osservazioni a lungo termine hanno consentito una nuova descrizione oceanografica dell'area, documentando la presenza di una quantità di caratteristiche finora mai segnalate con un simile dettaglio spaziale e temporale. The Malta-Sicily Channel is located within one of the busiest commercial routes in the Mediterranean Sea. Due to the presence of oil tankers and oil rigs, this stretch of sea is prone to oil spill events (both deliberate or accidental) with potentially significant impacts on the local ecosystems and economic activities, such as fishing and tourism activities. Prevention and mitigation measures are needed to reduce risks and impacts. Within this framework the high-frequency (HF) radar technology is able to monitor in near-real time surface currents and waves, thus representing an extraordinary tool to reduce the impact of marine pollution events. Assimilation of near real-time surface current data into numerical models greatly improves the short-term forecast of sea state conditions and, consequently, the forecast of oil spill movements and fate. This paper describes the characteristics and potential of the CALYPSO HF radar observing system. The network, in operation since August 2012, currently includes 4 SeaSonde (CODAR) HF radars working at 13.5 MHz. The system is able to provide 2D surface current maps of the Malta-Sicily Channel with high resolution over a 3x3 km grid, every hour. Surface currents derived by the CALYPSO system were validated using independent measurements (acoustic current meter and drifters), and their accuracy extensively proven. The long term datasets show unprecedented descriptions of surface currents patterns within the studied area.

Located in one of the main shipping lanes in the Mediterranean Sea, and in a strategic region for oil extraction platforms, the Malta-Sicily channel is exposed to significant oil spill risks. Shipping and extraction activities constitute a major threat for marine areas of relevant ecological value in the area, and impacts of oil spills on the local ecosystems and the economic activities, including tourism and fisheries, can be dramatic. Damages would be even more devastating for the Maltese archipelago, where marine resources represent important economic assets. Additionally, North Africa coastal areas are also under threat, due to their proximity to the Malta-Sicily Channel. Prevention and mitigation measures, together with rapid-response and decision-making in case of emergency situations, are fundamental steps that help accomplishing the tasks of minimizing risks and reducing impacts to the various compartments. Thanks to state-of-art technology for the monitoring of sea-surface currents in real-time under all sea-state conditions, the CALYPSO network of High-Frequency Radars represents an essential and invaluable tool for the specific purpose. HF radars technology provide a unique tool to track surface currents in near-real time, and as such the dispersion of pollutants can be monitored and forecasted and their origin backtracked, for instance through data assimilation into ocean circulation models or through short-term data-driven statistical forecasts of ocean currents. The network is constituted of four SeaSonde systems that work in the 13.5MHz frequency band. The network is operative since August 2012 and has been extensively validated using a variety of independent platforms and devices, including current meter data and drifting buoys. The latter provided clear evidences of the reliability of the collected data as for tracking the drifting objects. Additionally, data have provided a new insight into the oceanographic characteristics of the region, documenting the presence of a number of previously unreported features. The observing network represents an unique opportunity that exploit HF radar in coastal seas to meet Europe's needs for operational mapping of the surface ocean. Additionally, it provides expertise and support for a new generation of scientists and technical staff.

Background: The Objective of this study was to evaluate the association of BPD at 11-14 weeks and pregnancy outcome and to determine the role of incremental BPD growth from 11-14 weeks and 17-20 weeks in pregnancy outcome. Methods: Women (n=910) with singleton pregnancies were included in this prospective observational study after an early anomaly scan (11 to 14 weeks). Outcomes noted were the incidence of adverse events and the neonatal birth weight. Results: Irrespective of their original BPD at 11 to 14 weeks, fetuses had acquired optimum BPD growth rate on a follow up scan at 17-20 weeks, i.e., a majority of them fell in the 10 th to 90 th percentile group (P value

BACKGROUND: Several retrospective studies comparing off-pump and on-pump coronary surgery and the largest randomized studies published to date showed a lower number of grafts performed in patients submitted to off-pump coronary artery bypass surgery (OPCAB). These findings bring about the question of the general applicability of the results. We eliminated the selection bias correlated with the number of grafts per patient by comparing the short-term outcomes of patients undergoing OPCAB and standard coronary artery bypass grafting (CABG) matched for number of grafts. METHODS: Eighty-seven consecutive patients undergoing OPCAB (group A) were selected from the database of our Institution during a 2-year period. Matching was performed by iterative selection prioritizing, in the following sequence: number of grafts, EuroSCORE, and age. A total of 87 patients operated upon with the on-pump technique represented the control group (group B). RESULTS: There were no significant differences in preoperative characteristics between the two groups. The number of grafts per patient was 2.2 +/- 0.5 in group A and 2.2 +/- 0.5 in group B. Early mortality did not differ between the two groups and it was 2.2% (2 patients) in group A and 3.4% (3 patients) in group B (p = NS). The incidence of myocardial infarction did not differ between the two groups. No patient in either group had stroke or coma. Five (5.7%) patients in group A and 7 (8.0%) patients in group B had atrial fibrillation (p = NS). CONCLUSIONS: We were unable to demonstrate any significant differences in short-term mortality or morbidity outcome between OPCAB and standard CABG patients Our findings suggest that excellent results can be obtained with both surgical approaches.

Aim: To find out effect of serum luteinizing hormone (LH) levels on Day 1 (Day 2 of cycle) and Day 5 of stimulation and Day of trigger hCG in controlled ovulation stimulation with antagonist protocol of IVF-ICSI cycle on cycle outcome. Materials and Methods: This retrospective study was conducted in a University Hospital setting. One hundred and 62 patients underwent 165 cycles of controlled ovarian stimulation (COS) with recombinant Follicle stimulating hormone (rFSH) and Gonadotropin releasing hormone (GnRH) antagonist protocol in one year were included. Serum LH levels estimated on Day 1, Day 5 and the day of trigger hCG injections were divided into three groups based on the percentile and outcome measured. Results: The average number of follicles >18 mm in size were significant in the patients with LH levels between 25th to 75th percentile group on Day 1, Day 5 and Day of trigger hCG. The fertilization rate was significant (p= 0.04) in the patients with LH levels < 25thpercentile on the day of trigger hCG. Oocyte recovery rate, oocyte maturation rate and average number of best quality embryos (Grade 1) were not affected significantly in all three groups. Conclusion: In GnRH antagonist and rFSH protocols, low serum LH concentrations on the day of trigger hCG has better fertilization rate. LH levels between 25th and 75th percentile have an influence on the average number of > 18 mm size follicles. However, the LH level on Day 1, Day 5 and Day of hCG does not affect the cycle outcome in COS with antagonist protocol of IVF cycle. Hence, LH estimation is not mandatory in ART cycles with GnRH antagonist protocol.

The problem of monitoring pollution coming from oil spills assumes wide importance for the highly congested Sicily-Malta channel. Hydrocarbons, as well as other polluting substances, have a huge influence on the health status of the sea. In this paper we present the preliminary design of an underwater towed vehicle (UTV) to monitor the Sicily-Malta channel. The design of this towfish incorporates ideas for a camera, lens system and stroboscope illumination system that can be used to take images of phytoplankton and zooplankton having a size range of 100 microns up to 1 centimeter. The underwater platform includes a high definition (HD) camera for monitoring jellyfish population at different sea depths. Unlike the autonomous underwater vehicles (AUVs), an UTV is not independent and must be towed by a surface boat. This disadvantage is balanced by having a simpler design and control system and an increased payload for instruments, sensors and cameras due to the absence of heavy battery systems. In order to increase maneuverability, stability and depth control, actuated hydroplanes are used to vary the angle of attack and to change the total downward force exerted on the moving towfish. The depth of dive of the towfish is automatically controlled to a set value. Automatic control is preferred so as to reduce the work and human concentration necessary during a monitoring mission. The hydroplanes are used to control rolling and pitching of the towfish. This kind of corrective action and a means of knowing the inclination of the towfish are deemed to be necessary because of the effect that underwater currents may have on the dynamics of the towfish. In addition to active control against the rolling action, the main hydroplanes (wings) of the towfish are at a small anhedral angle in order to create a passive anti roll action by creating a corrective moment acting about the main longitudinal axis of the towfish. The stern of the towfish also carries a rudder. The rudder would mainly be used when turning and to steer the towfish away from the surface boat wake when taking surface or close to surface measurements. The towfish is towed via an umbilical cord which carries all the power supply and signal lines necessary for towfish control and data acquisition. The umbilical cord is mechanically strong enough in order to tow the underwater towfish which is subjected to hydrodynamic drag. For proper logging and mapping of pollutants and camera images it is required to know the exact position and positional depth of the towfish during a mission. The positional depth of the towfish is recorded by means of a depth sensor. The position of the towfish is found by having a Global Positioning System (GPS) on the surface boat coupled with a commercially available sonar based instrument that can be used to calculate the relative position between the surface boat and the towfish., peer-reviewed

This paper discusses the dynamic simulations of a Towfish equipped with three wings, two of which can be moved for a possible stability depth control. The models describing the 3D geometry of both vehicle and towing cable are implemented, their main parameters and the acting forces are evaluated and then simulated using a multibody dynamic software. Numerical values of the hydrodynamic forces and moments, obtained by numerical fluid dynamics analyses, are also added to the vehicle model in order to obtain a more accurate simulation of the open-loop behavior of the system. As shown in the Fig. 1, the airplane-shaped Towfish has three wings: a main fixed wing, a mobile stern wing and another mobile bow wing, called Canard wing. The vehicle length is 1.8 m, its height is 52.8 cm and its width is 2 m., measured as the wingspan of the main wing. The system is designed as a not buoyant object, while the airfoil shape of the wings is chosen according to the NACA code. The towing cable has a length of 500 meters, a section diameter of 30 mm and its linear weight in the seawater is 1.27 kg/m. Finally, the connection between the cable and the towfish is reproduced by a spherical joint. Numerical simulation results show a depth stability of the vehicle associate with a positive pitch angle. The used method can provide some appreciable results to create a stability control system.

his paper presents the workspace analysis of a 6 DOF Parallel Kinematic Machine (PKM) designed for machining. The analysis is based on kineto-statics indexes able to highlight different aspects of the manipulator performances. Beside the classical jacobian based indexes (kinematic manipulability, isotropy, stiffness) the analysis has been also performed using new indexes recently defined in order to remove dependencies on the adopted units used to measure length, angles, force and torques. Moreover the new indexes decouple the effects of rotations and translations. These indexes are used to optimise the geometrical design of the PKM.