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This research evidences the impact of Materials Science and Engineering Clubs as an outreach effort to expand the education and training required for a competitive Nanotechnology workforce beyond traditional STEM areas. An engineering perception questionnaire was implemented as a pre-test/post-test to track student perceptions and goals throughout the academic year to identify trends amongst gender and school level groups. Findings (107 students) show a perceived increase in student knowledge and interest for different fields of study, based on pre/post-test responses, with differences amongst gender and school level groups (middle school and high school). Also, significant differences in students’ aspirations for higher education degree were found among school level and gender. Results show that over 20% of participants increased their aspirations to higher education degrees and their interests in pursuing STEM degrees at end of the academic year. Specific findings on engineering perceptions and perceived level of knowledge and interest in science, engineering, materials, and nanotechnology as a result of club participation and student’s educational aspirations, expectations and future study plans are discussed along with implications for future STEM education.
There is a need to expand the fundamental skills in science and engineering to include innovation & entrepreneurship (I&E) skills as core competencies. To better prepare the future Nanotechnology workforce, the University of Puerto Rico-Mayagüez Nanotechnology Center, broadened the educational content beyond traditional skills in science and engineering. The Center, offers a rich educational program for materials and nano scientists that aims to create the next generation of knowledgeable, experienced professionals, and successful entrepreneurs, who can develop value-added innovations that can spur economic growth and continue to impact the quality of life for society. Within the educational program an Entrepreneurship Education Co-Curricular Program (EEP) incorporates I&E training into the Materials Science, Nanotechnology, STEM (Science, Technology, Engineering, and Mathematics) faculty and student experiences. The EEP consists of a two-year series of workshops that seek to develop an entrepreneurial mindset, including five key topics: 1) Generation of Ideas, 2) Entrepreneurial Vision, 3) Early Assessment of Ideas, 4) Identification of Opportunities, and 5) Strategic Thinking. The EEP goals, target audience, and implementation strategy, is described with an evaluation tool to assess the program’s success in developing an entrepreneurial mindset.
Inspired by the continuation-passing encoding of binary sessions, we describe a simple approach to embed a hybrid form of session type checking into any programming language that supports parametric polymorphism. The approach combines static protocol analysis with dynamic linearity checks. To demonstrate the effectiveness of the technique, we implement a well-integrated OCaml module for session communications. For free, OCaml provides us with equirecursive session types, parametric behavioural polymorphism, complete session type inference, and session subtyping.
An analysis of type Ia supernova (SNIa) events in early type galaxies from the Cappellaro et al.  database provides strong evidence that the rate of type Ia supernovae (SNe) in radio-loud galaxies is about 4 times higher than the rate measured in radio-quiet galaxies, i.e. SNIa-rate(radio-loud) SNe per century and per 1010
(SNU) as compared to SNIa-rate(radio-quiet)= 0.11 ± 0.03 SNU. The exact value of the enhancement is still rather uncertain, but is likely to be in the range ~ 2 – 7. We discuss the possible causes of this result and we conclude that the enhancement of the SNIa explosion rate in radio-loud galaxies has the same common origin as their being strong radio sources, but that there is no causality link between the two phenomena. We argue that repeated episodes of interaction and/or mergers of early type galaxies with dwarf companions are responsible for inducing both strong radio activity in ~14% of early type galaxies, and the ~ 1 Gyr old stellar population needed to supply an adequate number SNIa progenitors.
Active Galactic Nuclei (AGN) are ideal sources for multi-wavelength studies as their emission can cover almost 20 orders of magnitude in frequency from the radio to the γ-ray band. After reviewing their basic properties, I will assess how well we know the multifrequency spectra of AGN as a class. I will then briefly illustrate how currently available and forthcoming sky surveys will help in addressing some of the open questions of AGN studies. Finally, an analysis of the problem of the missing Type 2 QSO will exemplify the dangers of monochromatic sky surveys for AGN.
In a recent review paper we summarized the current status of unification of radio-loud AGN (Urry & Padovani 1995 PASP 107, 803), connecting high-luminosity (FR II) radio galaxies with quasars, and low-luminosity (FR I) radio galaxies with BL Lac objects. Unified schemes are motivated by the knowledge that AGN appearance depends strongly on orientation (Fig. 1): optical/UV light from the centers of many AGN is obscured by circumnuclear matter, and in radio-loud AGN, bipolar relativistic jets beam light along the jet axes. Understanding these radiation anisotropics allows us to unify apparently distinct classes of AGN that differ primarily because of orientation.
Our review described the classification and general properties of AGN and summarized the evidence for anisotropic emission caused by circumnuclear obscuration and relativistic beaming. We outlined the evidence, both observed isotropic properties and statistical arguments, for connecting FR IIs with quasars and FR Is with BL Lacs. The population statistics (with beaming) are in accordance with available data and suggest γ ≃ 5 for low-luminosity AGN and γ ≃ 10 for high-luminosity AGN. The distinctions between X-ray-selected and radio-selected BL Lac objects, and between BL Lacs and flat-spectrum variable quasars, still not understood, provide clues to the underlying physics of blazars. Our review discussed several possible problems and complications, and concluded with a list of the ten questions we believe are the most pressing in this field.
The WARPS (Wide-Angle ROSAT Pointed Survey) blazar survey is a deep X-ray search for BL Lac objects and flat-radio-spectrum quasars (FRSQs), drawn from a cross-correlation of serendipitous sources in the ROSAT PSPC database WGACAT (White et al. 1994) with the Green Bank 6 cm and 20 cm (Condon et al. 1989, Condon & Broderick 1985), the Parkes radio (Bolton et al. 1979), and the Parkes-MIT-NRAO (Griffith & Wright 1993, Wright et al. 1994, Griffith et al. 1994, 1995) catalogs. Our sample contains 165 new blazar candidates and 95 previously known blazars.
We have analyzed the X-ray spectra of all BL Lacs observed (as pointed or serendipitous sources) by ROSAT. Spectral indices were obtained from the hardness ratios given in the WGA catalogue, a large list of X-ray sources generated from all the ROSAT PSPC pointed observations. The selection of the objects was done by cross-correlating the first revision of the WGA catalogue with our recent catalogue of BL Lacs. This resulted in 163 observations of 85 distinct BL Lacs, which correspond to about half the confirmed BL Lacs presently known. This represents the largest number of BL Lacs for which homogeneous X-ray spectral information is available and the largest BL Lac sample ever studied at X-ray frequencies.
In this work we explore the mechanisms responsible for Random Telegraph Noise
(RTN) fluctuations in HfOx Resistive Random Access Memory (RRAM)
devices. The statistical properties of the RTN are analyzed in many operating
conditions exploiting the Factorial Hidden Markov Model (FHMM) to decompose the
multilevel RTN traces in a superposition of two-level fluctuations. This allows
the simultaneous characterization of individual defects contributing to the RTN.
Results, together with multi-scale physics-based simulations, allows thoroughly
investigating the physical mechanisms which could be responsible for the RTN
current fluctuations in the two resistive states of these devices, including
also the charge transport features in a comprehensive framework. We consider two
possible options, which are the Coulomb blockade effect and the possible
existence of metastable states for the defects assisting charge transport.
Results indicate that both options may be responsible for RTN current
fluctuations in HRS, while RTN in LRS is attributed to the temporary screening
effect of the charge trapped at defect sites around the conductive filament.
Gas tungsten arc welding-tungsten inert gas (GTAW-TIG) is focused in literature as an alternative choice for joining high strength low alloy steels; this study is performed to compare the differences between gas metal arc welding-metal inert gas (GMAW-MIG) and GTAW welding processes. The aim of this study is to characterize microstructure of dissimilar transformation induced plasticity steels (TRIP) and martensitic welded joints by GMAW and GTAW welding processes. It was found that GMAW process lead to relatively high hardness in the HAZ of TRIP steel, indicating that the resultant microstructure was martensite. In the fusion zone (FZ), a mixture of phases consisting of bainite, ferrite and small areas of martensite were present. Similar phase’s mixtures were found in FZ of GTAW process. The presence of these mixtures of phases did not result in mechanical degradation when the GTAW samples were tested in lap shear tensile testing as the fracture occurred in the heat affected zone. In order to achieve light weight these result are benefits which is applied an autogenous process, where it was shown that without additional weight the out coming welding resulted in a high quality bead with homogeneous mechanical properties and a ductile morphology on the fracture surface. Scanning electron microscopy (SEM) was employed to obtain information about the specimens that provided evidence of ductile morphology.
In this article, I explore the conditions of the media in Italy by taking into consideration a variety of elements: the context of media legislation and media concentration that have favoured the interests of Silvio Berlusconi, and the role of progressive agency (media professionals, citizens' groups) as they worked within those constraints to keep alive the flames of democracy during the ‘Berlusconi era’. This perspective is intended to provide an alternative interpretation to what has become the prevailing view of contemporary Italy: an ‘abnormal’ country; the ‘Sick Man of Europe’; worse yet: a country of ‘servants’. The framework of analysis includes the influence of the media-magnate-turned-politician on media legislation and the television sector, but also evaluates the important roles that media professionals and citizens have played to improve pluralism. The article argues that despite extreme levels of media concentration and an unprecedented conflict of interests, a commitment to engage in political discourse has continued to characterise Italy's political culture. This commitment has been expressed by a multiplicity of actors, from journalists and media professionals to citizens' organisations and media activists.
Dementia with Lewy bodies (DLB) is underrecognised in clinical
To investigate whether performing a 123I-ioflupane injection
(123I-FP-CIT also called DaTSCANTM) single
photon emission computed tomography (SPECT) scan in patients with
possible DLB would lead to a more certain diagnosis (probable DLB or
We randomised 187 patients with possible DLB 2:1 to have a scan or not
(control group). The outcome measure was a change in diagnosis to
probable DLB or non-DLB.
There were 56 controls and 114 scanned patients, of whom 43% had an
abnormal scan. More patients in the imaging group had a change in
diagnosis compared with controls at 8 and 24 weeks (61%
(n = 70) v. 4% (n =
2) and 71% (n = 77) v. 16%
(n = 9); both P<0.0001).
Clinicians were more likely to change the diagnosis if the scan was
abnormal (82%) than if it was normal (46%).
Imaging significantly contributed to a more certain diagnosis, proving to
be a useful adjunct in the work-up of patients with possible DLB.
The subtyping relation defined for dyadic session type theories may compromise the liveness of multi-party sessions. In this paper, we define a fair subtyping relation for multi-party session types that preserves liveness, we relate it with the subtyping relation for dyadic session types and provide coinductive, axiomatic and algorithmic characterizations for it.
A multiparty session forms a unit of structured communication among many participants which follow communication sequences specified as a global type. When a process is engaged in two or more sessions simultaneously, different sessions can be interleaved and can interfere at runtime. Previous work on multiparty session types has ignored session interleaving, providing a limited progress property ensured only within a single session, by assuming non-interference among different sessions and by forbidding delegation. This paper develops, besides a more traditional, compositional communication type system, a novel static interaction type system for global progress in dynamically interleaved and interfered multiparty sessions. The interaction type system infers causalities of channels making sure that processes do not get stuck at intermediate stages of sessions also in presence of delegation.
We present our latest results on the connection between the accretion rate and the power of relativistic jets. To this aim we use blazars, whose jet is pointing at us, with visible broad emission lines, along with broad lineless radio–galaxies. We trace the jet power with two proxies (gamma–ray and radio luminosities), while the broad emission lines are a direct measure of the accretion disc luminosity. We find a correlation between the broad emission line and the gamma–ray or luminosities in blazars, suggesting a direct tight connection between the jet and the accretion rate. Only extending our analysis to radio–galaxies, and using as jet tracer the radio luminosity, we are finally able to conclude that jetted AGN can accrete both through a radiatively efficient accretion disc and a hot accretion flow, depending on the accretion rate. We finally observe the transition between the two states among the family of jetted AGN.
The connection between the bi-polar hafnia-based resistive-RAM (RRAM) operational characteristics and dielectric structural properties is considered. Specifically, the atomic-level description of RRAM, which operations involve the repeatable rupture/recreation of a localized conductive path, reveals that its performance is determined by the outcome of the initial forming process defining the structural characteristics of the conductive filament and distribution of the oxygen ions released from the filament region. The post-forming ions spatial distribution in the cell is found to be linked to a degree of dielectric oxygen deficiency, which may either assist or suppress the resistive switching processes.
With the goal of investigating the link between black hole (BH) and star formation (SF) activity, we study a deep sample of radio selected star forming galaxies (SFGs) and active galactic nuclei (AGNs). Using a multi-wavelength approach we characterize their host galaxies properties (stellar masses, optical colors, and morphology). Moreover, comparing the star formation rate derived from the radio and far-infrared luminosity, we found evidences that the main contribution to the radio emission in the radio-quiet AGNs is star-formation activity in their host galaxy.
We present our very recent results on the sub-mJy radio source populations at 1.4 GHz based on the Extended Chandra Deep Field South VLA survey, which reaches ~ 30 μJy, with details on their number counts, evolution, and luminosity functions. The sub-mJy radio sky turns out to be a complex mix of star-forming galaxies and radio-quiet AGN evolving at a similar, strong rate and declining radio-loud AGN. While the well-known flattening of the radio number counts below 1 mJy is mostly due to star-forming galaxies, these sources and AGN make up an approximately equal fraction of the sub-mJy sky. Our results shed also light on a fifty-year-old issue, namely radio emission from radio-quiet AGN, and suggest that it is closely related to star formation, at least at z ~ 1.5 − 2. The implications of our findings for future, deeper radio surveys, including those with the Square Kilometre Array, are also discussed. One of the main messages, especially to non-radio astronomers, is that radio surveys are reaching such faint limits that, while previously they were mainly useful for radio quasars and radio galaxies, they are now detecting mostly star-forming galaxies and radio-quiet AGN, i.e., the bulk of the extragalactic sources studied in the infrared, optical, and X-ray bands.
In the lead-up to the Square Kilometre Array (SKA) project, several next-generation radio telescopes and upgrades are already being built around the world. These include APERTIF (The Netherlands), ASKAP (Australia), e-MERLIN (UK), VLA (USA), e-EVN (based in Europe), LOFAR (The Netherlands), MeerKAT (South Africa), and the Murchison Widefield Array. Each of these new instruments has different strengths, and coordination of surveys between them can help maximise the science from each of them. A radio continuum survey is being planned on each of them with the primary science objective of understanding the formation and evolution of galaxies over cosmic time, and the cosmological parameters and large-scale structures which drive it. In pursuit of this objective, the different teams are developing a variety of new techniques, and refining existing ones. To achieve these exciting scientific goals, many technical challenges must be addressed by the survey instruments. Given the limited resources of the global radio-astronomical community, it is essential that we pool our skills and knowledge. We do not have sufficient resources to enjoy the luxury of re-inventing wheels. We face significant challenges in calibration, imaging, source extraction and measurement, classification and cross-identification, redshift determination, stacking, and data-intensive research. As these instruments extend the observational parameters, we will face further unexpected challenges in calibration, imaging, and interpretation. If we are to realise the full scientific potential of these expensive instruments, it is essential that we devote enough resources and careful study to understanding the instrumental effects and how they will affect the data. We have established an SKA Radio Continuum Survey working group, whose prime role is to maximise science from these instruments by ensuring we share resources and expertise across the projects. Here we describe these projects, their science goals, and the technical challenges which are being addressed to maximise the science return.
EMU is a wide-field radio continuum survey planned for the new Australian Square Kilometre Array Pathfinder (ASKAP) telescope. The primary goal of EMU is to make a deep (rms ∼ 10 μJy/beam) radio continuum survey of the entire Southern sky at 1.3 GHz, extending as far North as +30° declination, with a resolution of 10 arcsec. EMU is expected to detect and catalogue about 70 million galaxies, including typical star-forming galaxies up to z ∼ 1, powerful starbursts to even greater redshifts, and active galactic nuclei to the edge of the visible Universe. It will undoubtedly discover new classes of object. This paper defines the science goals and parameters of the survey, and describes the development of techniques necessary to maximise the science return from EMU.