Studying the Inner Regions of Young Binary Systems with Near-Infrared Interferometry

The circumstellar regions of young stellar objects (YSOs) are some of the most interesting environments in astronomy. The leftover material from star formation takes the form of enormous discs of dust and gas extending out to a thousand astronomical units. The outer regions of these protoplanetary discs, being cold and relatively large in scale, have been extensively studied by radio telescopes. Usually shrouded in opaque dust, the regions closer to the stars are best studied in the infrared. Here, the central YSO interacts with the disc, accreting and ejecting material, and planets, asteroids and comets are formed. Understanding how stars interact with their discs can therefore tell us how both evolve, and can help us understand the origin of our own solar system. It also can teach us more about systems very different to our own -- such as binary systems. The majority of stars are part of multiple systems, and in recent years we have also found increasing numbers of binary YSOs. The dynamical interaction between the stars and the inner disc can lead to complex features such as spirals, warps and disc truncation, affecting their rates of accretion and ejection, as well as affecting planetary formation. As the population of binary YSOs grows, we are finding a much larger diversity in the inner regions of their discs than previously thought. Observing these processes has historically been difficult because of the extremely small angular scales on which they occur -- on the order of milli-arcseconds -- which limits their study with traditional telescopes. \\ In spite of this, the study of young stars and their discs has rapidly become one of the most dynamic areas of astronomy in recent decades. Advances in computing power have allowed for more complex simulations of circumstellar environments. Simultaneously, developments in technology and engineering have substantially increased the set of observable protoplanetary discs, allowing us to rapidly develop and advance ideas of star formation and evolution. The focus of my PhD was on one such technique: near-infrared interferometry. By interfering the light from multiple individual telescopes, it is possible to obtain resolutions far in excess of any single-dish telescope, allowing us to probe inner disc regions with a precision never before possible. This is especially important in the context of close binary YSOs, where dynamic interactions between the stars and the disc can cause large changes to the circumstellar environment which cannot be reliably determined from simulations. In these cases, the feedback from observations of individual systems can be used to calibrate and inform further refinements to the theory. The thesis is laid out as follows. Chapter~\ref{ch:yso} introduces the general star formation paradigm, including star formation and YSO classification, as well as a discussion on circumstellar discs around single stars. In Chapter~\ref{ch:binaries}, I extend this to binary objects, which were the focus of my research. Chapter~\ref{ch:interferometry} describes the basic theory behind optical and near-infrared interferometry, its history and the challenges which it poses to anyone wishing to interpret its observables. In this chapter I describe the basic operation of the interferometers which I used over the course of my PhD, the VLTI and the CHARA Array. After this theoretical overview, I present the work which was the focus of my PhD: a deep study into two individual young binary systems. Chapter~\ref{ch:mwc166} is dedicated to analysis of observations we took of MWC\,166\,A, a massive YSO with a combined mass of $17\,M_\odot$ located at a distance of 1\,kpc. This is a mysterious system with very strong $K$-band line emission, often associated with disc accretion, but little evidence of a substantial disc itself. In this chapter, I define for the first time a full three-dimensional orbit of the system, which has a period of $368\,\mathrm{d}$, and establish stellar parameters and the evolutionary state of both components, finding that the primary component is likely a main-sequence object while the secondary is just in the process of final contraction. I also constrain the geometry and spectral characteristics of the Br\,$\gamma$ and He\,\textsc{i} emission lines, and find the most likely origin to be a Be decretion disc in Keplerian rotation. Chapter~\ref{ch:hd104237} uses similar techniques to analyse a rather different young binary, HD\,104237\,A. This T\,Tauri with a combined mass of $4.3\,M_\odot$ lies about ten times closer to us and has a much tighter orbit of $20\,\mathrm{d}$. It also has a much denser inner disc region than MWC\,166\,A, with both components actively accreting from the circumbinary disc, and this is reflected in the strong but variable Br\,$\gamma$ emission arising from the two components. In this chapter, I derive an orbit for the system, constrain its age and determine fundamental stellar parameters for both components. I also model the circumstellar emission both in the dust continuum, which takes the form of a truncated circumbinary disc, and analyse the rapidly-changing Br\,$\gamma$ emission in the inner region on an epoch-by-epoch basis. This emission shows signs of variable accretion onto both stars, as well as components originating from the circumbinary environment. \\Both these studies use spectro-astrometric and spectro-interferometric techniques to showcase the usefulness of the high angular resolution afforded by near-infrared interferometry to gain unique insights into binary-disc interaction, dynamical truncation and binary accretion. This process will only accelerate in future, as new designs of interferometers with even greater precision will unlock an ever-larger tranche of systems, expanding our knowledge of these endlessly-fascinating objects further and further.Science and Technology Facilities Counci

Stress indicators in steers at slaughtering

This work aimed to assess the blood modifications of some slaughtering-linked stress hormones in cattle subject to butcher standardized procedures. The blood samples of 20 Limousine 12-13 months old steers have been collected before slaughtering, during lairage, and after stunning by captive bolt gun, during exsanguination. The plasma level of epinephrine, norepinephrine, cortisol and beta-endorphin have been assayed by EIA. The data indicate that catecholamines, cortisol and beta-endorphin did not significantly increase after stunning in these animals

Molecular epidemiological investigation of multidrug-resistant Acinetobacter baumannii strains in four Mediterranean countries with a multilocus sequence typing scheme

Thirty-five multidrug-resistant Acinetobacter baumannii strains, representative of 28 outbreaks involving 484 patients from 20 hospitals in Greece, Italy, Lebanon and Turkey from 1999 to 2009, were analysed by multilocus sequence typing. Sequence type (ST)2, ST1, ST25, ST78 and ST20 caused 12, four, three, three and two outbreaks involving 227, 93, 62, 62 and 31 patients, respectively. The genes bla oxa-58, bla oxa-23 and bla oxa-72 were found in 27, two and one carbapenem-resistant strain, respectively. In conclusion, A. baumannii outbreaks were caused by the spread of a few strains

evaluation of animal welfare and milk production of goat fed on diet containing hydroponically germinating seeds

Hydroponic fodder is a particularly nutritious feed, rich in protein and vitamins such as ß-carotene, trace elements and enzymes. It may also offer the advantage of a continuous availability. A pilot plant for hydroponically production of germinating seeds was built in an area of the same farm where the trial took place. Three homogeneous groups of 30 Jonica breed goats in lactation (4th-5th parity) were used to evaluate the effects of two different levels of partial dietary substitution with hydroponically germinating (h.g.) oat on plasma levels of cortisol and milk production. Germinated oat was used after 7 days of hydroponic growth. Control group (T) received only feed (fodder and oat integrated with complement feed). The other 2 groups were fed on diet containing different levels (1,5Kg - group A; 3Kg - group B) of hydroponically germinating oat. Goats showed a small interest in fresh feed during the trial period. The integration with hydroponically germinating oat in partial substitution of the traditional feed in the diet of goat did not significantly affect biochemical and haematological parameters

Thyrotropin modulates low density lipoprotein binding activity in FRTL-5 thyroid cells.

Abstract FRTL-5 cells possess high affinity low density lipoprotein (LDL) receptors which bind, internalize, and degrade LDL. When FRTL-5 cells are deprived of thyrotropin (TSH) the binding of LDL increases more than 2-fold. Upon addition of TSH, at a concentration of 1 x 10(-10) M or greater, LDL binding decreases rapidly and within 24 h reaches the level which is typical of FRTL-5 cells chronically stimulated by TSH. The data available suggest that TSH-dependent down-regulation of LDL receptor activity is exerted through a reduction of the number of active LDL receptors, with no change in affinity. It is unlikely that the synthesis of LDL receptors is impaired, since LDL receptor messenger RNA is not decreased by TSH. The effect of the hormone on LDL receptor activity can be mimicked by 8-Br-cAMP and is completely abolished by the protein synthesis inhibitor cycloheximide but not by actinomycin D. TSH regulation of LDL receptor activity is lost in v-ras Ki-transformed FRTL-5 cells (Ki Mol) which also have lost TSH dependence for adenylate cyclase activation and growth. However, 8-Br-cAMP decreases LDL binding in Ki Mol FRTL-5 cells. The reduced availability of LDL receptor in TSH-stimulated FRTL-5 cells may be related to the increased membrane fluidity (Beguinot, F., Beguinot, L., Tramontano, D., Duilio, C., Formisano, S., Bifulco, M., Ambesi-Impiombato, F. S., and Aloj, S. M. (1987) J. Biol. Chem. 262, 1575-1582) or may reflect increased degradation of LDL receptors. We propose that a lower cholesterol uptake is needed in an actively proliferating cell population, to increase the production of isoprenoids whether it be for cholesterol biosynthesis or for the synthesis of other compounds requiring isoprenoid precursors

Clinical and environmental distribution of legionella pneumophila in a university hospital in italy: efficacy of ultraviolet disinfection

The molecular epidemiology of Legionella pneumophila in the 'V. Monaldi' University Hospital was studied. Seven cases of nosocomial Legionnaires' disease were diagnosed between 1999 and 2003. Two clinical legionella strains obtained from two patients in the adult cardiac surgery unit (CSU) and 30 environmental legionella strains from the paediatric and adult CSUs, neonatal intensive care unit (NICU) and the cardiorespiratory intensive care unit (CR-ICU) were serotyped and genotyped. L. pneumophila serogroup 1/Philadelphia with an identical pulsed-field gel electrophoresis (PFGE) profile A was isolated from two patients in the adult CSU, and from three and one water samples taken in the adult CSU and the paediatric CSU, respectively, from 2001 to 2002. Furthermore, L. pneumophila serogroup 3 with an identical PFGE profile B was identified in 20 environmental strains from all wards, L. pneumophila serogroup 3 with PFGE profile C was identified in a single environmental strain from the CR-ICU, and non-pneumophila Legionella with identical PFGE profile D was identified in five environmental strains from the adult CSU, paediatric CSU and NICU. Ultraviolet irradiation was effective in disinfection of the hospital water supplies in the adult and paediatric CSUs contaminated by L. pneumophila clone associated with nosocomial Legionnaires' disease. In conclusion, these data demonstrate that two cases of nosocomial legionellosis were caused by the persistence of a single clone of L. pneumophila serogroup 1/Philadelphia in the hospital environment, and that disinfection by ultraviolet irradiation may represent an effective measure to prevent nosocomial Legionnaires' disease. © 2005 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved

Trans-heterozygosity for mutations enhances the risk of recurrent/chronic pancreatitis in patients with Cystic Fibrosis

Background: Recurrent (RP) and chronic pancreatitis (CP) may complicate Cystic Fibrosis (CF). It is still unknown if mutations in genes involved in the intrapancreatic activation of trypsin (IPAT) or in the pancreatic secretion pathway (PSP) may enhance the risk for RP/CP in patients with CF.Methods: We enrolled: 48 patients affected by CF complicated by RP/CP and, as controls 35 patients with CF without pancreatitis and 80 unrelated healthy subjects. We tested a panel of 8 genes involved in the IPAT, i.e. PRSS1, PRSS2, SPINK1, CTRC, CASR, CFTR, CTSB and KRT8 and 23 additional genes implicated in the PSP.Results: We found 14/48 patients (29.2%) with mutations in genes involved in IPAT in the group of CF patients with RP/CP, while mutations in such genes were found in 2/35 (5.7%) patients with CF without pancreatitis and in 3/80 (3.8%) healthy subjects (p < 0.001). Thus, we found mutations in 12 genes of the PSP in 11/48 (22.9%) patients with CF and RP/CP. Overall, 19/48 (39.6%) patients with CF and RP/CP showed one or more mutations in the genes involved in the IPAT and in the PSP while such figure was 4/35 (11.4%) for patients with CF without pancreatitis and 11/80 (13.7%) for healthy controls (p < 0.001).Conclusions: The trans-heterozygous association between CFTR mutations in genes involved in the pathways of pancreatic enzyme activation and the pancreatic secretion may be risk factors for the development of recurrent or chronic pancreatitis in patients with CF

An Ethnographer Lured into Darkness

No matter the combination of methods ethnographers bring to their research design and to participant observation, our pursuit to log, interpret, analyse and present the lives of those we meet is never an entirely intellectual or objective one. Ethnographic fieldwork is intimately sensory (Pink, Doing sensory ethnography, Sage, London, 2015), invokes our imagination (Sparkes, Qualitative research in sport and exercise, 1:21–35, 2009) and requires us to actively navigate social landscapes (Hammersley and Atkinson, Field relations. Ethnography: Principles in practice, Routledge, Stoodleigh, 2007). There is a tendency for these elements to fade in terms of visibility and immediacy within the research process. For those in accord with (Davies, Reflexive ethnography: A guide to researching selves and others, Routledge, New York, 2008), continuous reflexive labour becomes a core praxis to monitor the ways we observe and participate in this textured environment. Without this, we are left in the dark and are less able to see how we can (or should) respond to the nitty–gritty qualitative nature of ethnography. In this Chapter, two of methodological vignettes will act as entry points to unpack a set of tensions that commanded my attention during an eighteen months ethnography in Higher Education. ‘You Look Like an Ivory Tower Student’, for example, begins to troubleshoot ethnographic participation within educational environments. ‘Going Dark’, on the other hand, problematises the prioritisation of visual observations that are implicit in ethnographic tradition. Throughout these discussions a metaphor of being lured into darkness is offered as a productive orientation for ethnography

Incorporating weekly carboplatin in anthracycline and paclitaxel-containing neoadjuvant chemotherapy for triple-negative breast cancer: propensity-score matching analysis and TIL evaluation

Background The generation of data capturing the risk-benefit ratio of incorporating carboplatin (Cb) to neoadjuvant chemotherapy (NACT) for triple-negative breast cancer (TNBC) in a clinical practice setting is urgently needed. Tumour-infiltrating lymphocytes (TILs) have an established role in TNBC receiving NACT, however, the role of TIL dynamics under NACT exposure in patients receiving the current standard of care is largely uncharted. Methods Consecutive TNBC patients receiving anthracycline-taxane [A-T] +/- Cb NACT at three Institutions were enrolled. Stromal-TILs were evaluated on pre-NACT and residual disease (RD) specimens. In the clinical cohort, propensity-score-matching was used to control selection bias. Results In total, 247 patients were included (A-T = 40.5%, A-TCb = 59.5%). After propensity-score-matching, pCR was significantly higher for A-TCb vs A-T (51.9% vs 34.2%, multivariate: OR = 2.40, P = 0.01). No differences in grade &gt;= 3 haematological toxicities were observed. TILs increased from baseline to RD in the overall population and across A-T/A-TCb subgroups. TIL increase from baseline to RD was positively and independently associated with distant disease-free survival (multivariate: HR = 0.43, P = 0.05). Conclusions We confirmed in a clinical practice setting of TNBC patients receiving A-T NACT that the incorporation of weekly Cb significantly improved pCR. In addition, A-T +/- Cb enhanced immune infiltration from baseline to RD. Finally, we reported a positive independent prognostic role of TIL increase after NACT exposure