Star formation and dust extinction in nearby star forming and starburst galaxies

We study the star formation rate and dust extinction properties of a sample of nearby star forming galaxies as derived from Halpha and UV (2000 A) observations and we compare them to those of a sample of starburst galaxies. The dust extinction in Halpha is estimated from the Balmer decrement and the extinction in UV using the FIR to UV flux ratio or the attenuation law for starburst galaxies of Calzetti et al. The Halpha and UV emissions are strongly correlated with a very low scatter for the star forming objects and with a much higher scatter for the starburst galaxies. The Halpha to UV flux ratio is found larger by a factor ~ 2 for the starburst galaxies. We compare both samples with a purely UV selected sample of galaxies and we conclude that the mean Halpha and UV properties of nearby star forming galaxies are more representative of UV selected galaxies than starburst galaxies. We emphasize that the Halpha to UV flux ratio is strongly dependent on the dust extinction: the positive correlation found between F{Halpha}/F{UV}$ and F{FIR}/F{UV} vanishes when the Halpha and UV flux are corrected for dust extinction. The Halpha to UV flux ratios converted into star formation rate and combined with the Balmer decrement measurements are tentatively used to estimate the dust extinction in UV.Comment: accepted for publication in Astronomy & Astrophysic

'From Zionism to Communism': Emilio Sereni and the Consiglio di Gestione in postwar Italy

This essay demonstrates that it is impossible to appreciate the actions of the Italian communist Emilio Sereni without considering his Zionist background. Anyone who is interested in understanding the complexities of communism in the past century and to avoid simplistic conclusions about this ideology will benefit from the study. The problem at stake is that researchers often approach communism in a monolithic manner, which does not adequately explain the multiform manifestations (practical and theoretical) of that phenomenon. This ought to change and to this extent this essay hopes to contribute to that recent strand of historical research that challenges simplistic views on communism. More specifically, by analysing the Management Councils that Sereni created in postwar Italy, we can see that many of their features in fact derived from, or found their deepest origins in, his previous experience as a committed socialist Zionist. The study, then, also relates Sereni to and looks at the broader experiences of early twentieth-century Zionism and Italian communism in the early postwar years

Improving Reliability of Medical Device Tracking Using Unique Device Identification

The term “disruptive innovation” has been the buzzword of industries looking to create technological advancements in their respective fields ever since the term was first coined in 1995. In order to invest in the future of the industry, companies are beginning to focus on new, innovative ideas that come into the market as a low-cost alternative to the sustaining innovations currently in place. Similar business-models can be seen in the healthcare industry, as physicians look to disruptive innovations to provide methods of diagnosis and treatment that are easier to perform and maintain. Companies, from medical device manufacturers to the hospitals using these devices, are now working to comply with the Federal Drug Administration Amendments Act of 2007’s requirements of Unique Device Identifiers on all equipment – a new, standardized identification system to ensure all necessary information about a device is provided. This honors thesis analyzes the recent history of disruptive innovations, in all industries and specifically healthcare, and the emergence and benefits of Unique Device Identification. Modeling of the implementation of Unique Device Identifiers in an industrial setting resulted in a 16.55% time improvement of the affected phases of the recall process, preventing 30 fatalities. When a benefit-cost analysis was performed – comparing the value of a human life to the cost of UDI implementation – the benefit of implementation outweighed the costs by 277%. Keywords: Disruptive Innovation; Healthcare; Transportation; Reliability; Medical Devices; Real-Time Location Systems; FDAAA; Unique Device Identification; Agent Based Modelin

Experimental investigation of the mooring system of a wave energy converter in operating and extreme wave conditions

A proper design of the mooring systems for Wave Energy Converters (WECs) requires an accurate investigation of both operating and extreme wave conditions. A careful analysis of these systems is required to design a mooring configuration that ensures station keeping, reliability, maintainability, and low costs, without affecting the WEC dynamics. In this context, an experimental campaign on a 1:20 scaled prototype of the ISWEC (Inertial Sea Wave Energy Converter), focusing on the influence of the mooring layout on loads in extreme wave conditions, is presented and discussed. Two mooring configurations composed of multiple slack catenaries with sub-surface buoys, with or without clump-weights, have been designed and investigated experimentally. Tests in regular, irregular, and extreme waves for a moored model of the ISWEC device have been performed at the University of Naples Federico II. The aim is to identify a mooring solution that could guarantee both correct operation of the device and load carrying in extreme sea conditions. Pitch motion and loads in the rotational joint have been considered as indicators of the device hydrodynamic behavior and mooring configuration impact on the WEC

Fractional viscoelastic models for power-law materials

Soft materials often exhibit a distinctive power-law viscoelastic response arising from broad distribution of time-scales present in their complex internal structure. A promising tool to accurately describe the rheological behaviour of soft materials is fractional calculus. However, its use in the scientific community remains limited due to the unusual notation and non-trivial properties of fractional operators. This review aims to provide a clear and accessible description of fractional viscoelastic models for a broad audience and to demonstrate the ability of these models to deliver a unified approach for the characterisation of power-law materials. The use of a consistent framework for the analysis of rheological data would help classify the empirical behaviours of soft and biological materials, and better understand their response

Fractional viscoelastic models for power-law materials.

Soft materials often exhibit a distinctive power-law viscoelastic response arising from broad distribution of time-scales present in their complex internal structure. A promising tool to accurately describe the rheological behaviour of soft materials is fractional calculus. However, its use in the scientific community remains limited due to the unusual notation and non-trivial properties of fractional operators. This review aims to provide a clear and accessible description of fractional viscoelastic models for a broad audience and to demonstrate the ability of these models to deliver a unified approach for the characterisation of power-law materials. The use of a consistent framework for the analysis of rheological data would help classify the empirical behaviours of soft and biological materials, and better understand their response

An X-ray Survey of Galaxies in Pairs

Results are reported from the first survey of X-ray emission from galaxies in pairs. The sample consists of fifty-two pairs of galaxies from the Catalog of Paired Galaxies Karachentsev (1972) whose coordinates overlap ROSAT Position Sensitive Proportional Counter pointed observations. The mean observed log l_x for early-type pairs is 41.35 +/-0.21 while the mean log l_x predicted using the l_x-l_b relationship for isolated early-type galaxies is 42.10 +/-0.19. With 95% confidence, the galaxies in pairs are underluminous in the X-ray, compared to isolated galaxies, for the same l_b. A significant fraction of the mixed pair sample also appear similarly underluminous. A spatial analysis shows that the X-ray emission from pairs of both types typically has an extent of ~10 - 50 kpc, much smaller than group intergalactic medium and thus likely originates from the galaxies. CPG 564, the most X-ray luminous early-type pair, 4.7x10^42 ergs/sec, is an exception. The extent of it's X-ray emission, >169 kpc, and HWHM, ~80 kpc, is comparable to that expected from an intergalactic medium. The sample shows only a weak correlation, ~81% confidence, between l_x and l_b, presumably due to variations in gas content within the galaxies. No correlation between l_x and the pair velocity difference, separation, or far-infrared luminosity is found though the detection rate is low, 22%.Comment: 40 pages, 6 jpg figures, ApJ (in press