Grating formation in BGG31 glass by UV exposure

A three-dimensional index variation grating in bulk BGG31 glass written using neither hydrogen loading nor germanium doping is demonstrated. This material is useful for fabricating ion-exchanged waveguides, and its photosensitivity to ultraviolet (UV) radiation at 248nm has not been previously explored. Intensity measurements of the Bragg diffracted spots indicated a maximum index variation (Delta n) of similar to 4 x 10(-5)

Determinants associated with obesity and physical activity in the public and private schools of the city of palermo

Introduction: Obesity is a medical condition associated with premature death and it is a risk factor for many chronic diseases. In this context, performing a regular physical activity promotes a healthy lifestyle, with significant health benefits. The aim of the study was to investigate behaviors that increase the risk of obesity and the determinants that encourage physical activity among adolescents. Materials and methods: The HBSC (Health Behavior in School-aged Children) questionnaire was administered to students in Palermo's private and public schools. For the sampling of public schools the protocol of the HBSC Surveillance System was followed; for the private ones it was opportunistic. Results: Private school students are more likely to exercise more than 3 days per week (OR 1.58) and are more likely to exercise more than 2 times a week (OR 2.08). Obese students in private schools in Palermo are more likely to perform physical activity for less than 3 days a week (OR 3.52) and a higher risk of not having breakfast (OR 10.11) and a snack between main meals (OR 3.82) every day. For all the schools examined, it emerged that obese subjects are more likely not to consume fruit (OR 3.13), to stay more than 6 hours a day in front of PCs and video games (OR 3.24) and more than 2 hours a day in front of TV (OR 3.79). Male students are more likely to perform physical activity for more than 3 days per week (OR 1.48) and intense physical activity at least 2 times per week (OR 1.76) Conclusions: It is necessary to intervene early with training on school and family in order to promote correct and responsible food choices and increase the level of physical activity among students. Therefore prevention interventions must be an integral part of coherent strategies based on tests of agreed effectiveness in order to minimize the risk linked to the development of diseases

Polarisation-independent Bragg gratings in ion-exchanged glass channel waveguides

The polarisation dependence of Bragg gratings photowritten in ion-exchanged glass waveguides is characterised for waveguides with different mask-opening widths and burial depths. It is found that polarisation-independent gratings can be written in waveguides with a wide variation in fabrication parameters

Network layer security: Design for a cross layer architecture

Traditional modular layering schemes have served a major part in the development of a variety of protocols. However, as the physical layer impairments become more unpredictable, a cross layer design (CLD) which is dynamic in nature provides better performance. CLD introduces new challenges in protocol design as well as in the area of security. Using numerical analysis, we show that a link layer design employing header compression and cross layer signalling to protect protocol headers can limit packet discarding. This paper also reviews the IPsec protocol and describes how IPsec can be modified for cross layer architecture. © 2007 IEEE

Gratings photowritten in ion-exchanged glass channel waveguides

Gratings are photowritten in ion-exchanged glass channel waveguides. The transmission of these waveguides shows a rejection dip of almost 20dB. The polarisation dependence of these waveguide gratings is measured and discussed

Ion-exchanged waveguide add/drop filter

An add/drop filter is fabricated using ion-exchanged waveguides and photowritten Bragg gratings. The device exhibits 20 dB extinction ratios and 3 dB bandwidths of 0.4 nm (100 GHz)

Il rilievo fotogrammetrico del Castello di Maredolce a Palermo

Le tecniche di rilievo fotogrammetrico stanno trovando un sempre più largo impiego nel campo dei BB.CC. Esse, infatti, consentono una rappresentazione dei manufatti con un'elevata cura del dettaglio geometrico mediante la restituzione vettoriale ed una elevata definizione degli aspetti materici degli oggetti attraverso la realizzazione dei fotopiani, che forniscono informazioni sia metriche che qualitative dell'oggetto. Tali tecniche, pertanto, costituiscono un fondamentale strumento di supporto alle attività di diagnostica e restauro dei monumenti antichi. Il presente articolo illustra la metodologia, le fasi operative e gli strumenti impiegati per il rilievo fotogrammetrico di un edificio complesso: il Castello di Maredolce a Palermo. Nel caso in esame la geometria dell'edificio, i dislivelli del suolo e la presenza di elementi fisici generanti ombre sull'edificio hanno sensibilmente condizionato le operazioni di rilievo, consentendo di affrontare e risolvere una vasta compagine di problematiche che il rilievo di un edificio storico, sito in un contesto oggi urbanizzato, comporta. Lo scritto, in particolare, descrive il workflow seguito e le procedure impiegate sino alla modellazione 3D image-based. Quest'ultima è stata implementata a partire dal blocco fotogrammetrico georiferito ottenuto dall'orientamento dei fotogrammi. I fotopiani del castello prodotti sono stati utilizzati come texture fotorealistica del modello fotogrammetrico tridimensionale.The techniques related to the photogrammetric survey are even more widely used in the field of Cultural Heritage In fact, they allow a representation of artifacts with a high attention to the geometric detail by a vector restitution and a high definition of the textural aspects of objects: they based on the creation of photo-plans, which provide information both metrics and qualitative about the object. These techniques, therefore, are an essential tool supporting diagnostics and restoration of ancient monuments. This article discusses the methodology, the operational phases and the instruments used for the photogrammetric survey of a building complex: the Castle of Maredolce in Palermo. In this case the geometry of the building, the uneven ground and the pres ence of physical elements creating shadows on the building have significantly affected the operations of relief: they have allowed to address and solve a wide range of issues deriving from the survey of historic buildings that are located in a urban context today. This paper, in particular, describes the workflow and the procedures used until the 3D image-based modeling. The latter was implemented from the georeferenced photogrammetric block obtained by the orientation of the frames. The photo-plans of the castle have been used as photo-realistic texture of the photogrammetric three-dimensional model

Comparison between adenosine triphosphate bioluminescence and aerobic colony count to assess surface sanitation in the hospital environment

Background: Adenosine triphosphate bioluminescence produced by the firefly luciferase has been successfully introduced to verify cleaning procedures in the food industry according to the Hazard Analysis Critical Control Point program. Our aim was to evaluate the reliability of bioluminescence as a tool to monitor the effectiveness of sanitation in healthcare settings, in comparison with the microbiological gold standard. Methods: 614 surfaces of various material were randomly sampled in Policlinico University Hospital units in Palermo, Italy, to detect adenosine triphosphate bioluminescence and aerobic colony count. Linear regression model and Pearson correlation coefficient were used to estimate the relationship between the two variables of the study. Results: Aerobic colony count median was 1.71 colony forming units/cm2 (interquartile range = 3.8), whereas adenosine triphosphate median was 59.9 relative light units/cm2 (interquartile range = 128.3). Pearson coefficient R2 was 0.09. Sensitivity and specificity of bioluminescence test with respect to microbiology were 46% and 71%, whereas positive predictive value and negative predictive value were 53% and 65%, respectively. Conclusion: According to our results, there seemed to be no linear correlation between aerobic colony count and adenosine triphosphate values, suggesting that current bioluminescence technology has not any proportional relationships with culturable microbes contaminating environmental surfaces in health-care settings

A cross-layer architecture for satellite network security: CL-IPsec

Cross-layer architectures (CLAs) are proposed to improve performance in networks where physical layer impairments are unpredictable and provision of security services may be challenging, as in satellite networks. This paper proposes an extension to the IPsec protocol, named Cross-Layer IPsec (CL-IPsec), able to provide authentication and integrity services through a cross-layer architecture when the adopted protocol is UDP-Lite. This is suitable for multicast applications that are cost-effectively provided by satellite systems. A satellite emulation platform has been used to validate the CL-IPsec implementation and to evaluate the performance improvement derived from the proposed CLA. © 2008 IEEE

I tumori del rene

non presente (capitolo di libro