ANDRÉ BRETON AND J.R.R. TOLKIEN: SURREALISM, SUBCREATION AND FRODO’S DREAMS

Tolkien knew and correctly understood the Surrealism of André Breton and, although he did not share its fundamental theoretical assumptions, he nevertheless included surrealist dream experiences in his work through the dreams of Frodo. This thesis will be demonstrated by dividing the study into three sections: - the first section will examine the development of Breton’s Surrealism in England and demonstrating that the Inklings were well aware of this contemporary avant-garde ; - the second section, will explain what Surrealism meant to Breton, how well Tolkien understood this, and how his creative sub-theory turned out to be the opposite of the surrealist perspective; - the third section, will show that, despite this diversity, the character of Frodo also includes typically modern and surrealist dream experiences

Long term evaluation of operating theater planning policies

This paper addresses Operating Room (OR) planning policies in elective surgery. In particular, we investigate long-term policies for determining the Master Surgical Schedule (MSS) throughout the year, analyzing the tradeoff between organizational simplicity, favored by an MSS that does not change completely every week, and quality of the service offered to the patients, favored by an MSS that dynamically adapts to the current state of waiting lists, the latter objective being related to a lean approach to hospital management. Surgical cases are selected from the waiting lists according to several parameters, including surgery duration, waiting time and priority class of the operations. We apply the proposed models to the operating theater of a public, medium-size hospital in Empoli, Italy, using Integer Linear Programming formulations, and analyze the scalability of the approach on larger hospitals. The simulations point out that introducing a very limited degree of variability in MSS in terms of OR sessions assignment can largely pay off in terms of resource efficiency and due date performance

The IMF and Star Formation History of the Stellar Clusters in the Vela D Cloud

We present the results of a Near-Infrared deep photometric survey of a sample of six embedded star clusters in the Vela-D molecular cloud, all associated with luminous (~10^3 Lsun) IRAS sources. The clusters are unlikely to be older than a few 10^6 yrs, since all are still associated with molecular gas. We employed the fact that all clusters lie at the same distance and were observed with the same instrumental setting to derive their properties in a consistent way, being affected by the same instrumental and observational biases. We extracted the clusters' K Luminosity Functions (KLF) and developed a simple method to correct them for extinction, based on colour-magnitude diagrams. The reliability of the method has been tested by constructing synthetic clusters from theoretical tracks for pre-main sequence stars and a standard Initial Mass Function (IMF). The clusters' IMFs have been derived from the dereddened KLFs by adopting a set of pre-main sequence evolutionary tracks and assuming coeval star formation. All clusters are small (~100 members) and compact (radius \~0.1-0.2 pc); their most massive stars are intermediate-mass (~2-10 Msun) ones. The dereddened KLFs are likely to arise from the same distribution, suggesting that the selected clusters have quite similar IMFs and star formation histories. The IMFs are consistent with those derived for field stars and clusters. Adding them together we found that the ``global'' IMF appears steeper at the high-mass end and exhibits a drop-off at ~10 Msun. In fact, a standard IMF would predict a star with M>22.5 Msun within one of the clusters, which is not found. Hence, either high-mass stars need larger clusters to be formed, or the IMF of the single clusters is steeper at the high-mass end because of the physical conditions in the parental gas.Comment: 17 pages, 14 figures, to be published in Astronomy & Astrophysic

Protostellar clusters in intermediate-mass (IM) star forming regions

The transition between the low density groups of T Tauri stars and the high density clusters around massive stars occurs in the intermediate-mass (IM) range (M$_*$$\sim$2--8 M$_\odot$). High spatial resolution studies of IM young stellar objects (YSO) can provide important clues to understand the clustering in massive star forming regions. Aims: Our aim is to search for clustering in IM Class 0 protostars. The high spatial resolution and sensitivity provided by the new A configuration of the Plateau de Bure Interferometer (PdBI) allow us to study the clustering in these nearby objects. Methods: We have imaged three IM Class 0 protostars (Serpens-FIRS 1, IC 1396 N, CB 3) in the continuum at 3.3 and 1.3mm using the PdBI. The sources have been selected with different luminosity to investigate the dependence of the clustering process on the luminosity of the source. Results: Only one millimeter (mm) source is detected towards the low luminosity source Serpens--FIRS 1. Towards CB 3 and IC1396 N, we detect two compact sources separated by $\sim$0.05 pc. The 1.3mm image of IC 1396 N, which provides the highest spatial resolution, reveal that one of these cores is splitted in, at least, three individual sources.Comment: 4 pages, 3 figures, accepted for publication in Astronomy and Astrophysics Letters (Special Feature IRAM/PdB

Looking for outflow and infall signatures in high mass star forming regions

(Context) Many physical parameters change with time in star forming regions. Here we attempt to correlate changes in infall and outflow motions in high mass star forming regions with evolutionary stage using JCMT observations. (Aims) From a sample of 45 high mass star forming regions in three phases of evolution, we investigate the presence of established infall and outflow tracers to determine whether there are any trends attributable to the age of the source. (Methods) We obtained JCMT observations of HCO+/H13CO+ J=4-3 to trace large scale infall, and SiO J=8-7 to trace recent outflow activity. We compare the infall and outflow detections to the evolutionary stage of the host source (high mass protostellar objects, hypercompact HII regions and ultracompact HII regions). We also note that the integrated intensity of SiO varies with the full width at half maximum of the H13CO+. (Results) We find a surprising lack of SiO detections in the middle stage (Hypercompact HII regions), which may be due to an observational bias. When SiO is detected, we find that the integrated intensity of the line increases with evolutionary stage. We also note that all of the sources with infall signatures onto Ultracompact HII regions have corresponding outflow signatures as well.Comment: 9 pages, 5 figures, 5 tables. Accepted by A&

Young massive stars in the ISOGAL survey I. VLA observations of the ISOGAL l=+45 field

We present VLA radio continuum observations at 3.6 and 6 cm of a ~0.65 sq.deg. field in the galactic plane at l=+45deg . These observations are meant to be used in a comparison with ISO observations at 7 and 15 um of the same region. In this paper we compare the radio results with other radio surveys and with the IRAS-PSC. At 3.6 and/or 6 cm we detect a total of 34 discrete sources, 13 of which are found in five separate extended complexes. These are all multiple or single extended thermal ultra-compact HII (UCHII) regions. While for each of these complexes an IRAS counterpart could be reliably found, no IRAS counterpart could be reliably identified for any of the remaining 21 sources. Of these 21 compact sources, six are candidate UCHII regions, and the other 15 are most probably background extragalactic non-thermal sources. The five IRAS sources associated with the radio continuum complexes all satisfy the Wood & Churchwell (1989; WC89) color criteria for UCHII. None of the other 38 IRAS point sources present in our surveyed field show the same colors. This fraction of WC89 type to total IRAS sources is consistent with what is found over the entire galactic plane. The fact that, when observed with a compact VLA configuration, the IRAS sources with "UCHII colors" are found to be associated with arcminute-scale extended sources, rather than with compact or unresolved radio sources, may have important implications on the estimated lifetime of UCHII regions.Comment: 15 pages, 22 eps figures, A&A Supp. in press, higher resolution figures available at http://www.arcetri.astro.it/~lt/preprints/preprints.htm

Ultra-compact Embedded Clusters in the Galactic Plane

We have identified a previously unrecognized population of very compact, embedded low-mass Galactic stellar clusters. These tight (r$\approx$0.14 pc) groupings appear as bright singular objects at the few arcsec resolution of the Spitzer Space Telescope at 8 and 24 $\mu$m but become resolved in the sub-arcsecond UKIDSS images. They average six stars per cluster surrounded by diffuse infrared emission and coincide with 100 -- 300 M_{\sun} clumps of molecular material within a larger molecular cloud. The magnitudes of the brightest stars are consistent with mid- to early-B stars anchoring $\sim$80 M_{\sun} star clusters. Their evolutionary descendants are likely to be Herbig Ae/Be pre-main sequence clusters. These ultra-compact embedded clusters (UCECs) may fill part of the low-mass void in the embedded cluster mass function. We provide an initial catalog of 18 UCECs drawn from infrared Galactic Plane surveys.Comment: Accepted for publication in The Astrophysical Journals Letter

Dust trapping by spiral arms in gravitationally unstable protostellar discs

In this paper we discuss the influence of gravitational instabilities in massive protostellar discs on the dynamics of dust grains. Starting from a Smoothed Particle Hydrodynamics (SPH) simulation, we have computed the evolution of the dust in a quasi-static gas density structure typical of self-gravitating disc. For different grain size distributions we have investigated the capability of spiral arms to trap particles. We have run 3D radiative transfer simulations in order to construct maps of the expected emission at (sub-)millimetre and near-infrared wavelengths. Finally, we have simulated realistic observations of our disc models at (sub-)millimetre and near-infrared wavelengths as they may appear with the Atacama Large Millimetre/sub-millimetre Array (ALMA) and the High-Contrast Coronographic Imager for Adaptive Optics (HiCIAO) in order to investigate whether there are observational signatures of the spiral structure. We find that the pressure inhomogeites induced by gravitational instabilities produce a non-negligible dynamical effect on centimetre sized particles leading to significant overdensities in spiral arms. We also find that the spiral structure is readily detectable by ALMA over a wide range of (sub-)millimetre wavelengths and by HiCIAO in near-infrared scattered light for non-face-on discs located in the Ophiucus star-forming region. In addition, we find clear spatial spectral index variations across the disc, revealing that the dust trapping produces a migration of large grains that can be potentially investigated through multi-wavelenghts observations in the (sub-)millimetric. Therefore, the spiral arms observed to date in protoplanetary disc might be interpreted as density waves induced by the development of gravitational instabilities.Comment: 14 pages, 12 figures. Accepted for publication in MNRA