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Hi-5 is the L'-band (3.5-4.0 $\mu$m) high-contrast imager of Asgard, an instrument suite in preparation for the visitor focus of the VLTI. The system is optimized for high-contrast and high-sensitivity imaging within the diffraction limit of a single UT/AT telescope. It is designed as a double-Bracewell nulling instrument producing spectrally-dispersed (R=20, 400, or 2000) complementary nulling outputs and simultaneous photometric outputs for self-calibration purposes. In this paper, we present an update of the project with a particular focus on the overall architecture, opto-mechanical design of the warm and cold optics, injection system, and development of the photonic beam combiner. The key science projects are to survey (i) nearby young planetary systems near the snow line, where most giant planets are expected to be formed, and (ii) nearby main sequence stars near the habitable zone where exozodiacal dust that may hinder the detection of Earth-like planets. We present an update of the expected instrumental performance based on full end-to-end simulations using the new GRAVITY+ specifications of the VLTI and the latest planet formation models., Comment: 16 pages, 9 figures, SPIE 2022 "Astronomical Telescopes and Instrumentation" manuscript 12183-16

Background Acute diverticulitis (AD) is a common cause of presentation to emergency surgical services. Follow-up with endoluminal investigation to exclude colorectal cancer (CRC) remains controversial. Guidelines are increasingly moving to a more restrictive follow up based on severity of disease and age. The purpose of this study was to assess the prevalence of CRC in AD patients and the impact of follow-up on endoscopy services. Methods Patients admitted with a diagnosis of AD over a 2-year period were reviewed. The proportion of patients undergoing endoscopic follow-up and the CRC detection rate were recorded. The potential impact of a more conservative approach to follow-up was evaluated. Results There were 484 patients with AD presenting 546 times (M:F = 198:286; median age = 63 years). 80% of admissions were aged 50 or older. There were 43 emergency interventions in 39 patients (10 percutaneous drain; 33 surgery). The remainder were managed conservatively. 28 patients (5.1%) underwent colonic resection with cancer found in one specimen (3.6%). 286 patients underwent endoluminal follow-up with cancer diagnosed in 3 cases (1.0%). There was no significant difference in the prevalence of CRC between patients requiring emergency surgery and those managed conservatively, or between patients with complicated versus uncomplicated diverticulitis. Conclusion CRC masquerading as acute diverticulitis is rare. The incidence of neoplasia both at endoscopic follow-up and in patients requiring emergency intervention is low. Conservative follow-up strategies appear safe, but their effectiveness in reducing the burden on endoscopy services may be limited by current age-based recommendations.

Hi-5 is an ERC-funded project hosted at KU Leuven and a proposed visitor instrument for the VLTI. Its primary goal is to image the snow line region around young planetary systems using nulling interferometry in the L’ band, between 3.5 and 4.1 μm, where the contrast between exoplanets and their host stars is very advantageous. The breakthrough is the use of a photonic chip based beam combiner, which only recently allowed the required theoretical raw contrast of 10−3 in this spectral range. The VLTI long baseline interferometry enables to reach high angular resolution (4.2 mas at 3.8 μm wavelength with the Auxiliary Telescopes (ATs)), while high contrast detection is achieved using nulling interferometry. This polarisation requires a high degree of optical symmetry between the four pupils of the VLTI, only possible with precise phase, dispersion and intensity control systems. The instrument is currently in its design phase. In this paper, the warm optics design and the injection system up to the photonic chip are presented. The different properties of the design are presented including the optics used, the characteristics of the four beams and the current drawbacks. Particular attention is devoted to the optical alignment and the tolerance analysis in order to estimate the precision required for the alignment procedure and therefore to choose adapted optical mountings.

Aim: To report the impact of the SARS-CoV-2 pandemic on management and outcomes of paediatric appendicitis in the UK and Ireland. Methods: Prospective, multicentre observational cohort study at general surgical and specialist paediatric surgical centres in the United Kingdom and Ireland from 1st April to 31st July 2020. Primary outcome was treatment strategy used for acute appendicitis. Results: This study includes 2002 children treated for acute appendicitis of a median age of 10 (range 1–15) years and 605 children from a similar data set pre pandemic from 2017. In the pandemic cohort 560/2002(28%) were initially treated non operatively of whom 125/560(22%) proceeded to appendicectomy within initial hospital admission. Non operative treatment wasn't used in the pre pandemic cohort. Diagnostic imaging use was greater during the pandemic compared to pre pandemic (54vs31%; p < 0.00001) but overall use of laparoscopy was similar during both time periods (62.4vs66.6%). Hospital readmission rate was lower (8.7vs13.9%; p = 0.0002) during the pandemic than pre pandemic and Re-intervention rate was similar (2.9vs2.6%;p = 0.42). In cases treated operatively negative appendicectomy rate was lower during the pandemic than pre pandemic (4.4vs15.4%; p =0.0001), and during the pandemic was amongst the lowest ever reported in the UK. Conclusion: COVID-19 has had a significant impact on the management of children with appendicitis in the UK and Ireland. The rate of imaging and the use of non operative management increased, whilst the negative appendicectomy rate reduced. Overall, patient outcomes have not been adversely impacted by change in management during the pandemic. conclusion: Level I. Type of study: Prognosis study.

Active phase control is a vital component to any interferometry system. On a simple photonic device this can often be achieved using bulk optics before the chip, but for complicated systems active phase control on-chip is a vital component of the photonic design. One method of active phase control is using the thermo-optic effect. Using a chalcogenide waveguides, chromium heaters actively change the refractive index of the glass, this changes the optical path length of the light. This paper shows that chromium deposited above arms of a Mach-Zehnder interferometer will be able to produce multiple pi phase shifts at a rate of approximately 40 mW per π phase shift. Hence a chalcogenide based platform is suitable for a complicated photonic device like a Kernel-Nulling interferometer.

Direct imaging of exoplanets is vital for understanding star system formation and the evolutionary behaviour of exoplanets at large orbits. Typically, imaging a star system to find an exoplanet requires significant attenuation of the host star’s high flux in order to detect the much weaker planetary light. The most common method to do this is coronagraphy, which blocks the starlight with an amplitude mask or a null inducing phase mask [1]. An alternative and attractive method is nulling interferometry where light from multiple telescopes are used to simultaneously form a high resolution image (or its Fourier components) and also to form a null in the vicinity of the host star, thereby attenuating it [2]. This has the advantage over coronagraphy that it is not limited to using a single telescope and is thus able to probe deeper into a star system by virtue of the higher resolution available by an interferometric array.

Hybrid integration of different materials will allow for different functionalities such as passive, amplifying, nonlinear, electro-optic, detection etc to build “system on a chip” devices. The vertically stacked layer design commonly proposed significantly increases the difficulty of the lithography process for the bottom-most layer due to the overlying topology. A methodology for significantly improving the fabrication tolerance of planar directional couplers is therefore presented. A parametric design study reveals that significant dimensional sensitivity improvements exist for certain center-to-center spacings for both power and wavelength splitters.

2D materials, led by graphene, have been widely explored in the last decade as saturable absorber (SA) materials. Most of this work has focussed on fibre compatible designs for use in fibre lasers (e.g. fibre connector sandwich, D-shaped fibre). Realising chip based mode locked lasers is an important challenge, and little work has been carried out on planar waveguide SAs, Here, simulation results for the absorption performance of two types of graphene based TeO2 waveguide SA designs with suitably high absorption and low saturation threshold are presented.

The prevalence of negative symptoms (NS) at first episode of early-onset psychosis (EOP), and their effect on psychosis prognosis is unclear. In a sample of 638 children with EOP (aged 10–17 y, 51% male), we assessed (1) the prevalence of NS at first presentation to mental health services and (2) whether NS predicted eventual development of multiple treatment failure (MTF) prior to the age of 18 (defined by initiation of a third trial of novel antipsychotic due to prior insufficient response, intolerable adverse-effects or non-adherence). Data were extracted from the electronic health records held by child inpatient and community-based services in South London, United Kingdom. Natural Language Processing tools were used to measure the presence of Marder Factor NS and antipsychotic use. The association between presenting with ≥2 NS and the development of MTF over a 5-year period was modeled using Cox regression. Out of the 638 children, 37.5% showed ≥2 NS at first presentation, and 124 (19.3%) developed MTF prior to the age of 18. The presence of NS at first episode was significantly associated with MTF (adjusted hazard ratio 1.62, 95% CI 1.07–2.46; P = .02) after controlling for a number of potential confounders including psychosis diagnostic classification, positive symptoms, comorbid depression, and family history of psychosis. Other factors associated with MTF included comorbid autism spectrum disorder, older age at first presentation, Black ethnicity, and family history of psychosis. In EOP, NS at first episode are prevalent and may help identify a subset of children at higher risk of responding poorly to antipsychotics.

Over 15% of young people with autism spectrum disorders (ASD) will contemplate or attempt suicide during adolescence. Yet, there is limited evidence concerning risk factors for suicidality in childhood ASD. Electronic health records (EHRs) can be used to create retrospective clinical cohort data for large samples of children with ASD. However systems to accurately extract suicidality-related concepts need to be developed so that putative models of suicide risk in ASD can be explored. We present a systematic approach to 1) adapt Natural Language Processing (NLP) solutions to screen with high sensitivity for reference to suicidal constructs in a large clinical ASD EHR corpus (230,465 documents), and 2) evaluate within a screened subset of 500 patients, the performance of an NLP classification tool for positive and negated suicidal mentions within clinical text. When evaluated, the NLP classification tool showed high system performance for positive suicidality with precision, recall, and F1 scores all > 0.85 at a document and patient level. The application therefore provides accurate output for epidemiological research into the factors contributing to the onset and recurrence of suicidality, and potential utility within clinical settings as an automated surveillance or risk prediction tool for specialist ASD services.

The future of exoplanet detection lies in the mid-infrared (MIR). The MIR region contains the blackbody peak of both hot and habitable zone exoplanets, making the contrast between starlight and planet light less extreme. It is also the region where prominent chemical signatures indicative of life exist, such as ozone at 9.7 microns. At a wavelength of 4 microns the difference in emission between an Earth-like planet and a star like our own is 80 dB. However a jovian planet, at the same separation exhibits 60 dB of contrast, or only 20 dB if it is hot due to its formation energy or being close to its host star. A two dimensional nulling interferometer, made with chalcogenide glass, has been measured to produce a null of 20 dB, limited by scattered light. Measures to increase the null depth to the theoretical limit of 60 dB are discussed., Comment: Was published in SPIE: Optical and Infrared Interferometry and Imaging VI, Mike Ireland presented

Understanding exoplanet formation and finding potentially habitable exoplanets is vital to an enhanced understanding of the universe. The use of nulling interferometry to strongly attenuate the central starlight provides the opportunity to see objects closer to the star than ever before. Given that exoplanets are usually warm, the 4 microns Mid-Infrared region is advantageous for such observations. The key performance parameters for a nulling interferometer are the extinction ratio it can attain and how well that is maintained across the operational bandwidth. Both parameters depend on the design and fabrication accuracy of the subcomponents and their wavelength dependence. Via detailed simulation it is shown in this paper that a planar chalcogenide photonic chip, consisting of three highly fabrication tolerant multimode interference couplers, can exceed an extinction ratio of 60 dB in double nulling operation and up to 40 dB for a single nulling operation across a wavelength window of 3.9 to 4.2 microns. This provides a beam combiner with sufficient performance, in theory, to image exoplanets., Assigned issue as Vol. 23 No. 3 in Op. Express

In a sample of children and adolescents with first-episode psychosis, we investigated whether multiple treatment failure (MTF, defined as the initiation of a third trial of novel antipsychotic due to nonadherence, adverse effects, or insufficient response) was associated with comorbid autism spectrum disorders.Data were from the electronic health records of 638 children (51% male) aged from 10 to 17 years with first-episode psychosis (per ICD-10 criteria) from January 1, 2008, to November 1, 2014, referred to mental health services in South London, United Kingdom; data were extracted using the Clinical Record Interactive Search (CRIS) system. The effect of autism spectrum disorder comorbidity on the development of MTF during a 5-year period was modeled using Cox regression.There were 124 cases of MTF prior to the age of 18 (19.4% of the sample). Comorbid autism spectrum disorders were significantly associated with MTF (adjusted hazard ratio = 1.99; 95% CI, 1.19-3.31; P = .008) after controlling for a range of potential confounders. Other factors significantly associated with MTF included higher age at first presentation (P = .001), black ethnicity (P = .03), and frequency of clinical contact (P.001). No significant association between other comorbid neurodevelopmental disorders (hyperkinetic disorder or intellectual disability) and MTF was found.Children with first-episode psychosis and comorbid autism spectrum disorders at first presentation are less likely to have a beneficial response to antipsychotics.

Mental Health Records (MHRs) contain free- text documentation about patients’ suicide and suicidality. In this paper, we address the prob- lem of determining whether grammatic vari- ants (inflections) of the word “suicide” are af- firmed or negated. To achieve this, we pop- ulate and annotate a dataset with over 6,000 sentences originating from a large repository of MHRs. The resulting dataset has high Inter- Annotator Agreement ( κ 0.93). Furthermore, we develop and propose a negation detection method that leverages syntactic features of text 1 . Using parse trees, we build a set of ba- sic rules that rely on minimum domain knowl- edge and render the problem as binary clas- sification (affirmed vs. negated). Since the overall goal is to identify patients who are ex- pected to be at high risk of suicide, we focus on the evaluation of positive (affirmed) cases as determined by our classifier. Our negation detection approach yields a recall (sensitivity) value of 94.6% for the positive cases and an overall accuracy value of 91.9%. We believe that our approach can be integrated with other clinical Natural Language Processing tools in order to further advance information extrac- tion capabilities

This is the author accepted manuscript. the final version is available from Elsevier via the DOI in this record

Research into planets beyond our own star system has until recently relied on indirect imaging methods. Direct imaging methods are now establishing a foothold in the hunt for alien planets and habitable worlds. Nulling interferometry is a promising approach for suppressing the host star brightness and resolving surrounding planets. A key requirement in this method is the interference of light from multiple telescopes/baselines and free space optical devices have already rendered images of other worlds. Photonic chip based systems are also becoming accepted as means of accomplishing this but require, in particular, wide bandwidth, high precision on chip beam splitters. In this paper a design improvement is outlined to one of the most fabrication tolerant integrated beam splitter components that significantly increases its coupling bandwidth and therefore its bandwidth at high extinction. Preliminary experimental results from a fabricated device are also shown. The predicted bandwidth spans 3.8 - 4.1 μm at an extinction of ∼50 dB but at the expense of increasing the loss to 0.6 dB in transmission.

A 38-year-old woman with a history of endometrosis presented to hospital with a 24 h history of severe, stabbing right iliac fossa pain. On examination she was non-feverish and systemically well. Rebound tenderness was noted in the right iliac fossa without guarding. Urinanalysis was positive for leucocytes but blood tests were unremarkable with the exception of a C reactive protein of 7. CT of the abdomen was performed to elucidate the cause of her abdominal pain (figure 1). The CT revealed a 1.7 cm soft tissue nodule …

Australia and New Zealand may seem enticing but junior doctors need to think carefully before quitting the UK, says Harry Dean, who worked as a non-training surgical registrar at Dunedin Hospital in New Zealand