cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Cholesterol based mesogenic Schiff’s base derivatives with carbonate linkage: Synthesis, characterisation and photoluminescence study
Creators: name: Bairwa, Sagar K.
name: Sonera, Srujal A.
name: Tandel, R. C.
Publisher: name: Taylor & Francis
Year: 2023
Subjects: Biochemistry
Physical Sciences not elsewhere classified
Pharmacology
Biotechnology
Environmental Sciences not elsewhere classified
Chemical Sciences not elsewhere classified

description: The steroidal derivatives have been found to be extremely good mesogens since their origin. Due to their inherent chirality, they have the potential to induce a wide variety of liquid crystalline phases, including frustrated phases, depending on the structure of the steroidal skeleton and the substituents attached. In this report, thirteen new homologous Schiff’s base derivatives were synthesised by condensing 4-n-alkoxy aniline with 4-formyl phenyl cholesteryl carbonate. All the compounds were characterised using elemental analysis, FT-IR, 1H-NMR and 13C-NMR. In order to study the liquid crystalline behaviour of the synthesised compounds, optical texture studies were carried out using polarising optical microscope in heating and cooling cycles. The derivatives showed a variety of mesophases, including chiral nematic (N*), twist grain boundary-A (TGBA), smectic A (SmA) and chiral smectic C (SmC*) phases. The thermal behaviour was determined using a differential scanning calorimeter and thermogravimetric analysis. All the synthesised compounds are UV-active and show photoluminescence in the blue emission region with good quantum yield.
Synthesis and characterisation of chiral liquid crystal compounds containing cholesterol and D(+)-camphoric acid
Creators: name: Ma, Shuai-Yin
name: Zhang, Hong-Shuang
name: Zhi, Yuan-Sen
name: Wang, Lan-Fen
name: He, Xiao-Zhi
name: Zhang, Bao-Yan
name: Tian, Mei
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Biochemistry
subject: Microbiology
subject: FOS: Biological sciences
subject: Chemical Sciences not elsewhere classified

description: Two series of chiral liquid crystal compounds were synthesised from benzoic acid containing cholesterol with different carbon-chain lengths and bisphenol monoester containing camphoric acid with different carbon-chain lengths, named BCP-C and DCP-C. The structure of the monomers is characterised by IR, 1H NMR and 13C NMR, which indicate that the synthesised molecule conforms to the molecular design. The textures of monomers were characterised by POM, and their selective reflection was studied. It was found that the synthesised liquid crystal compounds exhibited good liquid crystal and optical properties. The phase transition behaviour was characterised using DSC, and the results were consistent with those observed by POM. TGA showed that they had good thermal stability.
Submillimetre galaxies in two massive protoclusters at z = 2.24: witnessing the enrichment of extreme starbursts in the outskirts of HAE density peaks
Creators: name: Zhang, Yuheng
name: Zheng, Xian Zhong
name: Shi, Dong Dong
name: Gao, Yu
name: Dannerbauer, Helmut
name: An, Fang Xia
name: Shu, Xinwen
name: Gao, Zhen-Kai
name: Wang, Wei-Hao
name: Wang, Xin
name: Cai, Zheng
name: Fan, Xiaohui
name: Fang, Min
name: Pan, Zhizheng
name: Liu, Wenhao
name: Tan, Qinghua
name: Qin, Jianbo
name: Ren, Jian
name: Qiao, Man
name: Wen, Run
name: Liu, Shuang
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Submillimetre galaxies represent a rapid growth phase of both star formation and massive galaxies. Mapping SMGs in galaxy protoclusters provides key insights into where and how these extreme starbursts take place in connections with the assembly of the large-scale structure in the early Universe. We search for SMGs at 850$\,μm$ using JCMT/SCUBA-2 in two massive protoclusters at $z=2.24$, BOSS1244 and BOSS1542, and detect 43 and 54 sources with $S_{850}>4\,$mJy at the $4σ$ level within an effective area of 264$\,$arcmin$^2$, respectively. We construct the intrinsic number counts and find that the abundance of SMGs is $2.0\pm0.3$ and $2.1\pm0.2$ times that of the general fields, confirming that BOSS1244 and BOSS1542 contain a higher fraction of dusty galaxies with strongly enhanced star formation. The volume densities of the SMGs are estimated to be $\sim15-$30 times the average, significantly higher than the overdensity factor ($\sim 6$) traced by H$α$ emission-line galaxies (HAEs). More importantly, we discover a prominent offset between the spatial distributions of the two populations in these two protoclusters -- SMGs are mostly located around the high-density regions of HAEs, and few are seen inside these regions. This finding may have revealed for the first time the occurrence of violent star formation enhancement in the outskirts of the HAE density peaks, likely driven by the boosting of gas supplies and/or starburst triggering events. Meanwhile, the lack of SMGs inside the most overdense regions at $z\sim2$ implies a transition to the environment disfavouring extreme starbursts.
description: 16pages, 11figures, accepted for publication in MNRAS
Comparing Lensing and Stellar Orbital Models of a Nearby Massive Strong-Lens Galaxy
Creators: name: Poci, Adriano
name: Smith, Russell J.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Exploiting the relative proximity of the nearby strong-lens galaxy SNL-1, we present a critical comparison of the mass estimates derived from independent modelling techniques. We fit triaxial orbit-superposition dynamical models to spatially-resolved stellar kinematics, and compare to the constraints derived from lens modelling of high-resolution photometry. From the dynamical model, we measure the total (dynamical) mass enclosed within a projected aperture of radius the Einstein radius to be $\log_{10} M_{\mathrm{Ein.}} = 11.00 \pm 0.02$, which agrees with previous measurements from lens modelling to within $5\%$. We then explore the intrinsic (de-projected) properties of the best-fitting dynamical model. We find that SNL-1 has approximately-constant, intermediate triaxiality at all radii. It is oblate-like in the inner regions (around the Einstein radius) and tends towards spherical at larger radii. The stellar velocity ellipsoid gradually transforms from isotropic in the very central regions to radially-biased in the outskirts. We find that SNL-1 is dynamically consistent with the broader galaxy population, as measured by the relative fraction of orbit `temperatures' compared to the CALIFA survey. On the mass--size plane, SNL-1 occupies the most-compact edge given its mass, compared to both the MaNGA and SAMI surveys. Finally, we explore how the observed lensing configuration is affected by the orientation of the lens galaxy. We discuss the implications of such detailed models on future combined lensing and dynamical analyses.
description: 15 pages, 13 figures. Accepted to MNRAS
Towards a global map of the artificial all-sky brightness
Creators: name: Kocifaj, Miroslav
name: Bará, Salvador
name: Falchi, Fabio
Publisher: name: arXiv
Year: 2022
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Modeling the hemispherical night sky brightness of anthropogenic origin is a demanding computational challenge, due to the intensive calculations required to produce all-sky maps with fine angular resolution including high-order scattering effects. We present in this Letter a physically consistent, semi-analytic two-parameter model of the all-sky radiance produced by an artificial light source that encodes efficiently the spectral radiance in all directions of the sky above the observer. The two parameters of this function are derived from the state of the atmosphere, the distance to the observer, and the source's angular and spectral emission pattern. The anthropogenic all-sky radiance at any place on Earth can be easily calculated by adding up the contributions of the surrounding artificial sources, using the information available from nighttime satellite imagery and ground-truth lighting inventories. This opens the way for the elaboration of a global world map of the artificial all-sky brightness.
description: 5 pages, 4 figures. Accepted version of a paper to be published in MNRAS Letters (2022)
Azopyridine-based hydrogen-bonded liquid crystals with thioether tail
Creators: name: Alaasar, Mohamed
name: Anders, Christian
name: Pashameah, Rami
name: Darweesh, Ahmed F.
Publisher: name: Taylor & Francis
Year: 2023
Subjects: Biophysics
Physical Sciences not elsewhere classified
Pharmacology
Biotechnology
Chemical Sciences not elsewhere classified
Science Policy

description: The first examples of azopyridine-based hydrogen-bonded liquid crystals (HBLCs) with thioether tail are reported. For this purpose, new HBLCs were designed and synthesised using 4-octylthiobenzoic acid as the proton donor and two different types of 4-alkoxyazopyridines as the proton acceptors. The first group of HBLCs has no lateral substitution, whereas the second has a lateral fluorine atom next to the alkoxy chain attached to the azopyridine derivative. Therefore, it was possible to investigate not only the effect of thioalkyl tail but also the influence of the aromatic core fluorination on the phase behaviour of the newly synthesised HBLCs. Hydrogen bond formation between the proton donor and the proton acceptors was confirmed using FTIR spectroscopy and X-ray diffraction (XRD), while the liquid crystalline behaviour of the HBLCs was investigated using differential scanning calorimetry (DSC) and polarised light microscope (PLM). It was found that all the reported HBLCs are mesomorphic exhibiting smectic A (SmA) and/or smectic C (SmC) phases depending on the length of the alkoxy chain as well as the presence or absence of the lateral fluorine atom. The possibility of photo-switching of the reported HBLCs under UV light irradiation was demonstrated for some selected examples in solution as well as in the bulk state.
A hybrid ionic liquid crystal comprising imidazolium surfactant-graphene oxide
Creators: name: Jiang, Yunxia
name: Meng, Jiaoyang
name: Xu, Bailing
name: Wang, Wu
name: Wang, Gengxin
name: Chen, Zhe
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Physical Sciences not elsewhere classified
subject: Microbiology
subject: FOS: Biological sciences
subject: Biotechnology
subject: Chemical Sciences not elsewhere classified
subject: Infectious Diseases
subject: FOS: Health sciences
subject: Plant Biology

description: To produce graphene oxide liquid crystal composites with better controllability, imidazolium surfactant with biphenyl mesogenic core (CBphCM) has been synthesised and used to modify the negatively charged surface of graphene oxide (GO) to obtain a hybrid ionic liquid crystal (CBphCM-GO). The process of GO and CBphCM recombination was monitored by various experimental techniques such as FT-IR, Uv-vis, Raman and XPS. The experimental results indicated that the C=O bonds on GO sheets are all reduced and C−O bonds are partially reduced due to the imidazolium units being electrically active and nitrogen-rich, and the presence of the N−O bonds indicates that a new hybrid is formed between CBphCM and GO. The recombination destroys the electrostatic repulsion balance among the GO lattices, and the CBphCM-GO is observed a fluffy appearance by TEM. The liquid crystal properties of CBphCM and CBphCM-GO were investigated by DSC, polarised optical microscopy (POM) and variable temperature X-ray diffraction, respectively. As an ionic liquid crystal, CBphCM has SmA as well as the rare SmC phases exhibits de Vries-like behaviour with a layer shrinkage. The liquid crystal properties of CBphCM-GO are derived from CBphCM, and the layer shrinkage behaviour from SmA to SmC phase has also been observed.
Gravity darkening and tidally perturbed stellar pulsation in the misaligned exoplanet system WASP-33
Creators: name: Kalman, Szilard
name: Bokon, Andras
name: Derekas, Aliz
name: M., Gyula Szabo
name: Hegedus, Viola
name: Nagy, Kristof
Publisher: name: arXiv
Year: 2022
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: WASP-33 is one of the few $δ$ Sct stars with a known planetary companion. By analyzing the stellar oscillations, we search for possible star-planet interactions in the pattern of the pulsation. We made use of the Transit and Light Curve Modeller (TLCM) to solve the light curve from the Transiting Exoplanet Survey Satellite (TESS). We include gravity darkening into our analysis. The stellar oscillation pattern of WASP-33 clearly shows signs of several tidally perturbed modes. We find that there are peaks in the frequency spectrum that are at or near the $3$rd, $12$th and $25$th orbital harmonics ($f_{orb} \sim 0.82$ d$^{-1}$). Also, there is a prominent overabundance of pulsational frequencies rightwards of the orbital harmonics, being characteristic of a tidally perturbed stellar pulsation, which is an outcome of star-planet interactions in the misaligned system. There are peaks in both the $δ$ Sct and $γ$ Dor ranges of the Fourier spectrum, implying that WASP-33 is a $γ$ Dor -- $δ$ Sct hybrid pulsator. The transit light curves are best fitted by a gravity darkened stellar model, and the planet parameters are consistent with earlier determinations.
description: Accepted in A&A on 12 March 2022, 6 pages, 4 figures
21 new long-term variables in the GX 339-4 field: two years of MeerKAT monitoring
Creators: name: Driessen, L. N.
name: Stappers, B. W.
name: Tremou, E.
name: Fender, R. P.
name: Woudt, P. A.
name: Armstrong, R.
name: Bloemen, S.
name: Groot, P.
name: Heywood, I.
name: Horesh, A.
name: van der Horst, A. J.
name: Koerding, E.
name: McBride, V. A.
name: Miller-Jones, J. C. A.
name: Mooley, K. P.
name: Rowlinson, A.
name: Wijers, R. A. M. J.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present 21 new long-term variable radio sources found commensally in two years of weekly MeerKAT monitoring of the low-mass X-ray binary GX 339-4. The new sources vary on time scales of weeks to months and have a variety of light curve shapes and spectral index properties. Three of the new variable sources are coincident with multi-wavelength counterparts; and one of these is coincident with an optical source in deep MeerLICHT images. For most sources, we cannot eliminate refractive scintillation of active galactic nuclei as the cause of the variability. These new variable sources represent $2.2\pm0.5$ per cent of the unresolved sources in the field, which is consistent with the 1-2 per cent variability found in past radio variability surveys. However, we expect to find short-term variable sources in the field as well as these 21 new long-term variable sources. We present the radio light curves and spectral index variability of the new variable sources, as well as the absolute astrometry and matches to coincident sources at other wavelengths.
description: 26 pages, 17 figures, 7 tables. Accepted for publication in MNRAS 2022 March 14. Received 2022 February 17; in original form 2021 July 11
Conserved temporal ordering of promoter activation implicates common mechanisms governing the immediate early response across cell types and stimuli
Creators: name: Vacca, Annalaura
Publisher: name: The University of Edinburgh
Year: 2019
Subjects: immediate-early genes
IEGs
FANTOM5 project
XBP1

description: The promoters of immediate early genes (IEGs) are rapidly activated in response to an external stimulus. These genes, also known as primary response genes, have been identified in a range of cell types, under diverse extracellular signals and using varying experimental protocols. Genomic dissection on a case-by-case basis has not resulted in a comprehensive catalogue of IEGs. I completed a rigorous meta-analysis of eight genome-wide FANTOM5 CAGE (cap analysis of gene expression) time-course datasets, and it revealed successive waves of promoter activation in IEGs, recapitulating known relationships between cell types and stimuli. I found a set of 57 (42 protein-coding) candidate IEGs possessing promoters that consistently drive a rapid but transient increase in expression following external stimulation. These genes show significant enrichment for known IEGs reported previously, pathways associated with the immediate early response, and include a number of non-coding RNAs with roles in proliferation and differentiation. There was strong conservation of the ordering of activation for these genes, such that 77 pairwise promoter activation orderings were conserved. Leveraging comprehensive CAGE time series data across cell types, I also observed extensive alternative promoter usage by such genes, which is likely to hinder their discovery from previous, smaller-scale studies. The common activation ordering of the core set of early-responding genes I identified may indicate conserved underlying regulatory mechanisms. By contrast, the considerably larger number of transiently activated genes that are specific to each cell type and stimulus illustrates the breadth of the primary response.
People living with Parkinson’s disease and their caregivers: a systematic review of psychosocial interventions; and, Psychological adjustment in people living with Parkinson’s disease and their caregivers: the role of coping, illness beliefs and self-compassion
Creators: name: Hodge, Lorna
Publisher: name: The University of Edinburgh
Year: 2019
Subjects: Parkinson’s disease
caregivers
psychosocial interventions
systematic review
dyad-based interventions
psychological adjustment
illness representations
self-compassion

description: This thesis comprises of a systematic review and an empirical study aimed to gain a greater understanding of the psychological needs of both people living with Parkinson’s disease (PD), their caregivers, and how these needs can be met. The systematic review aimed to evaluate the effectiveness of psychosocial interventions, where people living with PD and their caregivers are involved in the intervention (dyad-based), on psychological and additional outcomes measured. The review included 13 studies which met predefined eligibility criteria. Due to varied methodological quality of the studies, this review to an extent suggests that dyad-based psychosocial interventions may provide psychological benefits for people living with PD. Whereas, there was no substantive evidence to suggest dyad-based psychosocial interventions are effective for caregivers. More high-quality research is required to conclusively establish the effectiveness of these interventions for both people living with PD and their caregivers. The empirical study extended previous research examining the relationship between illness beliefs and coping with psychological adjustment (in terms of anxiety, depression and quality of life) in people living with PD and caregivers, whilst developing research in to the role of self-compassion within this process. A cross-sectional survey design with participants living with PD (N=66) and their caregivers (N=24) with the following measures was utilised; Brief COPE, Brief-Illness Perception Questionnaire, Self-Compassion Scale, Hospital Anxiety and Depression Scale, Parkinson’s disease Questionnaire 8-item and Adult Carer Quality of Life Questionnaire. The results of the study provided further evidence for the relationship between illness beliefs and psychological adjustment outcomes in people living with PD. In addition, the study provided preliminary evidence of a relationship between self-compassion and psychological adjustment outcomes of psychological distress in people living with PD. Further research of a larger and more representative sample is required to establish the role of illness beliefs, coping responses and self-compassion in psychological adjustment in both people living with PD and their caregivers.
Lense-Thirring effect on accretion flow from counter-rotating tori
Creators: name: Pugliese, D.
name: Stuchlik, Z.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We study the accretion flow from a counter-rotating torus orbiting a central Kerr black hole (BH). We characterize the flow properties at the turning point of the accreting matter flow from the orbiting torus, defined by the condition $u^ϕ= 0$ on the flow torodial velocity. The counter-rotating accretion flow and jet-like flow turning point location along BH rotational axis is given. Some properties of the counter-rotating flow thickness and counter-rotating tori energetics are studied.The maximum amount of matter swallowed by the BH from the counter-rotating tori is determined by the background properties. The fast spinning BH energetics depends mostly on BH spin rather than on the properties of the counter-rotating fluids or the tori masses. The turning point is located in a narrow orbital corona (spherical shell), for photons and matter flow constituents, surrounding the BH stationary limit (outer ergosurface), depending on the BH spin-mass ratio and the fluid initial momentum only. The turning corona for jet-like-flow has larger thickness, it is separated from the torus flow turning corona and it is closer to the BH stationary limit. Turning points of matter accreting from torus and from jets are independent explicitly of the details of the accretion and tori model. The turning corona could be observable due to an increase of flow luminosity and temperature. The corona is larger on the BH equatorial plane, where it is the farthest from the central attractor, and narrower on the BH poles.
description: to appear in MNRAS. 33 pages, 26 multipanel figures
A WISE view on extreme AGB stars
Creators: name: Groenewegen, Martin
Publisher: name: arXiv
Year: 2022
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: (abridged) Variability is a key property of stars on the asymptotic giant branch (AGB). Their pulsation period is related to the luminosity and mass-loss rate (MLR) of the star. Long-period variables (LPVs) and Mira variables are the most prominent of all types of variability of evolved stars. However, the reddest, most obscured AGB stars are too faint in the optical and have eluded large variability surveys. Our goal is to obtain a sample of LPVs with large MLRs by analysing WISE W1 and W2 light curves (LCs) for about 2000 sources, photometrically selected to include known C-stars with the 11.3 mu silicon carbide dust feature in absorption, and Galactic O-stars with periods longer than 1000 days. Epoch photometry was retrieved from the AllWISE and NEOWISE database and fitted with a sinus curve. Photometry from other variability surveys was also downloaded and fitted. For a subset of 316 of the reddest stars, spectral energy distributions (SEDs) were constructed, and, together with mid-infrared (MIR) spectra when available, fitted with a dust radiative transfer programme in order to derive MLRs. WISE based LCs and fits to the data are presented for all stars. Inspired by a recent paper, a number of non-variable OH/IRs are identified. Based on a selection on amplitude, a sample of about 750 (candidate) LPVs is selected of which 145 have periods over 1000 days, many of them being new. For the subset of the stars with the colours of C-rich extremely red objects (EROs) the fitting of the SEDs (and available MIR spectra) separates them into C- and O-rich objects. The number of Galactic EROs appears to be complete up to about 5~kpc and a total dust return rate in the solar neighbourhood for this class is determined. Based on the EROs in the Magellanic Clouds, a bolometric period luminosity is derived.
Diagnosing Triggered Star Formation in the Galactic H II region Sh 2-142
Creators: name: Sharma, Tanvi
name: Chen, Wen Ping
name: Panwar, Neelam
name: Sun, Yan
name: Gao, Yu
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Stars are formed by gravitational collapse, spontaneously or, in some cases under the constructive influence of nearby massive stars, out of molecular cloud cores. Here we present an observational diagnosis of such triggered formation processes in the prominent \ion{H}{2} region Sh\,2-142, which is associated with the young star cluster NGC\,7380, and with some bright-rimmed clouds as the signpost of photoionization of molecular cloud surfaces. Using near- (2MASS) and mid-infrared (WISE) colors, we identified candidate young stars at different evolutionary stages, including embedded infrared sources having spectral energy distributions indicative of active accretion. We have also used data from our optical observations to be used in SEDs, and from Gaia EDR3 to study the kinematics of young objects. With this young stellar sample, together with the latest CO line emission data (spectral resolution $\sim 0.16$~km~s$^{-1}$, sensitivity $\sim 0.5$~K), a positional and ageing sequence relative to the neighboring cloud complex, and to the bright-rimmed clouds, is inferred. The propagating stellar birth may be responsible, at least partially, for the formation of the cluster a few million years ago, and for the ongoing activity now witnessed in the cloud complex.
description: 15 figures, 2 tables, Accepted for publication in ApJ
Recognising the importance of preference change: A call for a coordinated multidisciplinary research effort in the age of AI
Creators: name: Franklin, Matija
name: Ashton, Hal
name: Gorman, Rebecca
name: Armstrong, Stuart
Publisher: name: arXiv
Year: 2022
Subjects: subject: Artificial Intelligence (cs.AI)
subject: Human-Computer Interaction (cs.HC)
subject: FOS: Computer and information sciences

description: As artificial intelligence becomes more powerful and a ubiquitous presence in daily life, it is imperative to understand and manage the impact of AI systems on our lives and decisions. Modern ML systems often change user behavior (e.g. personalized recommender systems learn user preferences to deliver recommendations that change online behavior). An externality of behavior change is preference change. This article argues for the establishment of a multidisciplinary endeavor focused on understanding how AI systems change preference: Preference Science. We operationalize preference to incorporate concepts from various disciplines, outlining the importance of meta-preferences and preference-change preferences, and proposing a preliminary framework for how preferences change. We draw a distinction between preference change, permissible preference change, and outright preference manipulation. A diversity of disciplines contribute unique insights to this framework.
description: Accepted at the AAAI-22 Workshop on AI For Behavior Change held at the Thirty-Sixth AAAI Conference on Artificial Intelligence (AAAI-22), 7 pages, 1 figure
Probing the parameters of the intergalactic medium using quasars
Creators: name: Dalton, Tony
name: Morris, Simon L.
name: Fumagalli, Michele
name: Gatuzz, Efrain
Publisher: name: arXiv
Year: 2022
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We continue our series of papers on intergalactic medium (IGM) tracers using quasi-stellar objects (QSOs), having examined gamma-ray bursts (GRBs) and blazars in earlier studies. We have estimated the IGM properties of hydrogen column density (Nhxigm), temperature and metallicity using XMM-Newton QSO spectra over a large redshift range, with a collisional ionisation equilibrium (CIE) model for the ionised plasma. The Nhxigm parameter results were robust with respect to intrinsic power laws, spectral counts, reflection hump and soft excess features. There is scope for a luminosity bias given both luminosity and Nhxigm scale with redshift, but we find this unlikely given the consistent IGM parameter results across the other tracer types reviewed. The impact of intervening high column density absorbers was found to be minimal. The Nhxigm from the QSO sample scales as (1 + z)^1.5+/-0.2. The mean hydrogen density at z = 0 is n0 = (2.8 +/- 0.3) x 10^-7 cm^-3, the mean IGM temperature over the full redshift range is log(T/K) = 6.5+/-0.1, and the mean metallicity is [X/H] = -1.3+/-0.1(Z 0.05). Aggregating with our previous GRB and blazar tracers, we conclude that we have provided evidence of the IGM contributing substantially and consistently to the total X-ray absorption seen in the spectra. These results are based on the necessarily simplistic slab model used for the IGM, due to the inability of current X-ray data to constrain the IGM redshift distribution
description: Accepted for publication in the MNRAS. 14 pages, 10 figures
Two-particle superposition effects in two-slit interference
Creators: name: Sancho, Pedro
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Entanglement can modify the interference patterns of multi-particle systems. We analyse, using the path integral formalism, a novel example of multi-particle interference and some unexplored aspects of this phenomenon by considering the two-slit arrangement with two distinguishable particles in a superposition state. The two components of entanglement, multiplicity of multi-particle terms and their coherence, can be studied separately by comparing the patterns of product, mixed and superposition states. This suggests a scheme to detect multi-particle superposition in some favourable cases. Moreover, the dependence of the effect on the entanglement degree, measured by the Schmidt number, is not a monotone.
title: Studies on the cuticle of the human body louse, Pediculus humanus humanus.
Creators: name: Lovell, GA
Publisher: name: London School of Hygiene & Tropical Medicine
Year: 1982

description: The cuticular ultrastructure and surface topography of the human body louse, Pediculus humanus humanus, were examined. Under light microscopy, pore canals were readily observed in unstained, cryostat sections of cuticle from various locations on the insect, particularly those areas composed of smooth, sclerotised cuticle. Transmission electron microscopy (TEM) studies revealed that, after attachment at the epidermis, the canals appeared to pass unbranched through the endocuticle (average thickness 4.5ji) with diameters around IOOOÁ. Branching occurred in the exocuticle (thickness l.Ofi) and finally in the epicuticle (thickness 2000A) to form wax canals with diameters around 100A. Pores or openings with diameters around lOOA were found during scanning electron microscopic (SEM) studies of the epicuticular surface and corresponded with the wax canals noted in the TEM examinations. A chemical analysis of the cuticular lipids of the louse was conducted using thin-layer chromatography (TLC), gas-liquid chromatography (GLC) and gaschromatography/mass spectroscopy (GC/MS) and the hydrocarbons were found to be the most abundant class (almost 75 per cent). Cholesteryl esters, triglycerides, 1,3-diglycerides, cholesterol and fatty acids were also present in that order of abundance. Cuticular hydrocarbons were comprised of over 43 components which contained from 21 to 35 total carbons per molecule. Four homologous series were present and consisted of n-alkanes (51.8 per cent of total cuticular hydrocarbons), n-alkenes (26.4 per cent), internally branched monomethylalkanes (12.1 per cent) and a tentatively identified series comprising dimethylalkanes (4.7 per cent). The effect of insecticide solvents upon the cuticular wax layer was investigated in vitro by comparing the solubility of a simulated cuticular wax mixture in a series of ten potential solvents. Results are discussed along with those from toxicity tests performed with the solvents on adult female lice and indicate a relationship between cuticular wax solubility and louse mortality. Studies with a fluorescent dye, demonstrated that wax-dissolving solvents entered the insect via at least two routes, i.e. cuticle and spiracles. The results are compared with the published work on other insect cuticular systems and the implications involving potential insecticide carriers discussed.
Radio detections of IR-selected runaway stellar bow shocks
Creators: name: Eijnden, J. Van den
name: Saikia, P.
name: Mohamed, S.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Massive stars moving at supersonic peculiar velocities through the interstellar medium (ISM) can create bow shocks, arc-like structures at the interface between the stellar wind and the ISM. Many such bow shocks have been detected and catalogued at IR wavelengths, but detections in other wavebands remain rare. Strikingly, while electrons are expected to be accelerated in the bow shock and their non-thermal emission may include synchrotron emission at low frequencies, only two massive runaway stellar bow shocks have to date been detected in the radio band. Here, we examine a sample of fifty IR-detected bow shocks from the E-BOSS catalogues in recently released radio images from the Rapid ASKAP Continuum Survey (RACS). We identify three confident and three likely counterparts, as well as three inconclusive candidates requiring confirmation via follow-up observations. These detections significantly increase the number of known radio massive stellar bow shocks and highlight the advantage of dedicated searches with current and next-generation radio telescopes. We investigate the underlying radio emission mechanism for these radio sources, finding a mix of free-free-dominated and synchrotron-dominated systems. We also discuss the non-detected targets by putting constraints on their emission properties and investigating their detectability with future observations. Finally, we propose several future avenues of research to advance the study and understanding of bow shocks at radio frequencies.
description: 17 pages, 12 figures, 3 tables. Resubmitted to MNRAS after final round of very minor referee comments
White Dwarf Photospheric Abundances in Cataclysmic Variables -- II. White Dwarfs With and Without a Mask
Creators: name: Godon, Patrick
name: Sion, Edward M.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Taking advantage of the now available Gaia EDR3 parallaxes, we carry out an archival {\it Hubble Space Telescope} (HST) far ultraviolet spectroscopic analysis of 10 cataclysmic variable systems, including 5 carefully selected eclipsing systems. We obtain accurate white dwarf (WD) masses and temperatures, in excellent agreement with the masses for 4 of the eclipsing systems. For three systems in our sample, BD Pav, HS 2214, and TT Crt, we report the first robust masses for their WDs. We modeled the absorption lines to derive the WD chemical abundances and rotational velocities for each of the ten systems. As expected, for five higher inclination ($i \gtrsim 75^{\circ}$) systems, the model fits are improved with the inclusion of a cold absorbing slab (an iron curtain masking the WD) with $N_{\rm H} \approx 10^{20}-10^{22}$cm$^{-2}$. Modeling of the metal lines in the HST spectra reveals that 7 of the 10 systems have significant subsolar carbon abundance, and six have subsolar silicon abundance, thereby providing further evidence that CV WDs exhibit subsolar abundances of carbon and silicon. We suggest that strong aluminum absorption lines (and iron absorption features) in the spectra of some CV WDs (such as IR Com) may be due to the presence of a {\it thin} iron curtain ($N_{\rm H}\approx 10^{19}$cm$^{-2}$) rather than to suprasolar aluminum and iron abundances in the WD photosphere. The derived WD (projected) rotational velocities all fall in the range $\approx 100-400$~km/s, all sub-Keplerian similar to the values obtained in earlier studies.
Cervical Spine Disease in Surgeons Performing Arthroscopy or Laparoscopy
Creators: name: Norheim, Elizabeth P.
name: Black, Mary Helen
name: Eunis W. Ngor
name: Jiaxiao M. Shi
name: Safran, Marc R.
name: Navarro, Ronald A.
Publisher: name: Taylor & Francis
Year: 2017
Subjects: Medicine
Biotechnology
Cancer

description: Background: Minimal research exists regarding cervical spine disorders in surgeons who perform endoscopy. Methods: A confidential on-line survey regarding neck pain (NP), spine disease (SD), and radiculopathy/myelopathy (R/M) was sent to 722 surgeons from a managed, group-based health care system. Results: 415 responded. 361░had endoscopy experience, of whom 24.4% had NP, 20.8% SD, and 3.9% R/M. Most respondents were less than 50 years of age (62.3%), and male (65.7%). Significant risk factors for NP included older age and female, whereas OB/Gyn specialty, increased age and job stress were for SD. After adjusting for age and gender, significant risk factors for NP and SD included greater surgeon experience. After also adjusting for job stress, significant risk factors for SD included increased surgeon experience and higher frequency of endoscopies. No association was found between use of digital OR. Conclusions: Endoscopy appears to place surgeons at higher risk of cervical disease. Level of Evidence: Level 3
Low X-ray surface brightness clusters: Implications on the scatter of the $M-T$ and $L-T$ relations
Creators: name: Andreon, S.
name: Trinchieri, G.
name: Moretti, A.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We aim at studying scaling relations of a small but well defined sample of galaxy clusters that includes the recently discovered class of objects that are X-ray faint for their mass. These clusters have an average low X-ray surface brightness, a low gas fraction and are under-represented (by a factor of 10) in X-ray surveys or entirely absent in SZ surveys. With the inclusion of these objects, we find that the temperature-mass relation has an unprecedented large scatter, 0.20+-0.03 dex at fixed mass, as wide as allowed by the temperature range, and the location of a cluster in this plane depends on its surface brightness. Clusters obey a relatively tight luminosity-temperature relation independently of the their brightness. We interpret the wide difference in scatter around the two relations as due to the fact that X-ray luminosity and temperature are dominated by photons coming from small radii (in particular for T we used a 300 kpc aperture radius) and strongly affected by gas thermodynamics (e.g. shocks, cool-cores), whereas mass is dominated by dark matter at large radii. We measure a slope of 2.0+-0.2 for the L500-T relation. Given the characteristics of our sample, this value is free from the collinearity (degeneracy) between evolution and slope and from hypothesis on the undetected population, that both affect the analysis of X-ray selected samples, and can therefore be profitably used both as reference and to break the above degeneracy of X-ray selected-samples.
description: MNRAS, 511, 4991: https://doi.org/10.1093/mnras/stac307 ; arxiv version is prior to english polishing, hyperlink, hyperref
Effects of Self-gravity on Mass-loss of the Post-impact Super-Earths
Creators: name: Huang, Jiang
name: Zhong, Wei
name: Yu, Cong
Publisher: name: arXiv
Year: 2022
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Kepler's observations show most of the exoplanets are super-Earths. The formation of super-Earth is generally related to the atmospheric mass loss that is crucial in the planetary structure and evolution. The shock driven by the giant impact will heat the planet, resulting in the atmosphere escape. We focus on whether self-gravity changes the efficiency of mass loss. Without self-gravity, if the impactor mass is comparable to the envelope mass, there is a significant mass-loss. The radiative-convective boundary will shift inward by self-gravity. As the temperature and envelope mass increase, the situation becomes more prominent, resulting in a heavier envelope. Therefore, the impactor mass will increase to motivate the significant mass loss, as the self-gravity is included. With the increase of envelope mass, the self-gravity is particularly important.
i-ETC - Launching a New Open Access Academic Journal
Creators: name: Fantoni, Alessandro
name: Marques, Paulo
name: Costa, João
name: Ferreira, Artur
name: Filipe, Porfírio
name: Jesus, Rui
name: Louro, Paula
name: Pinho, Pedro
name: Vaz, Cátia
Publisher: name: ISEL - High Institute of Engineering of Lisbon
Year: 2012
Subjects: Open Access; Open Journal System

description: This paper introduces the general editorial policy of i-ETC, a new online Open Access Journal. The publication of this academic journal is based on the software Open Journal System and it is maintained by the Department of Electronics, Telecommunications and Computer Engineering (DEETC), at the High Institute of Engineering of Lisbon (ISEL) in Lisbon.
description: i-ETC : ISEL Academic Journal of Electronics Telecommunications and Computers, Vol 1, No 1 (2012): Special Inauguration Issue
MOBILEWHEEL A mobile driving station
Creators: name: Cunha, Vitor
name: Campos, Carlos
Publisher: name: ISEL - High Institute of Engineering of Lisbon
Year: 2013
Subjects: Human-Computer Interaction; Driving Simulator; Mobile Sensing;

description: Current mobile devices (e.g., smartphones) are equipped with several sensors that allow different forms of user interaction. They also offer several connectivity options and a growing computing power which supports its use in new Human Computer Interaction (HCI) scenarios. This paper presents the mobileWheel, a system that exploits the capabilities of current mobile devices as a means of interaction with a real-time graphical driving simulation running on a desktop computer. The application on the mobile device performs data acquisition from various sensors (focusing on the 3D accelerometer) and also provides different types of feedback to the user. This system represents a ubiquitous, simple and affordable alternative approach to the traditional control of virtual vehicles in driving simulators and could also be applied in other similar architectures. To evaluate and validate this approach several tests were conducted with volunteer users. The control mode where the virtual vehicle is fully controlled by the accelerometer had the highest acceptance and produced the best results.
description: i-ETC : ISEL Academic Journal of Electronics Telecommunications and Computers, Vol 2, No 1 (2013): The CETC2011 Issue
Function and Meaning: The Double Aspects of Technology
Creators: name: Feenberg, Andrew
Publisher: name: ISEL - High Institute of Engineering of Lisbon
Year: 2012
Subjects: Philosophy of Technology; Function; Meaning; Marx; Lukács; Heidegger; Marcuse; Simpson; Borgmann

description: This paper traces the theoretical background to the split between function and meaning in the modernity theories of Marx, Lukács, Weber and Marcuse. It then discusses attempts to overcome the split in the recent philosophies of technology of Simpson and Borgmann. These attempts fail but help to focus the issue. A discussion of contemporary struggles over information technology offers a more hopeful perspective on a possible resolution of the split and suggests a new look at Heidegger’s phenomenology of action. The conclusion of the paper shows that Heidegger offers resources for addressing the relation of function and meaning which he himself did not develop.
description: i-ETC : ISEL Academic Journal of Electronics Telecommunications and Computers, Vol 1, No 1 (2012): Special Inauguration Issue
Uncertainty in Phylogenetic Tree Estimates
Creators: name: Willis, Amy
name: Bell, Rayna
Publisher: name: Taylor & Francis
Year: 2018
Subjects: subject: Medicine
subject: Pharmacology
subject: Biotechnology
subject: Evolutionary Biology
subject: FOS: Biological sciences
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: Ecology
subject: 69999 Biological Sciences not elsewhere classified
subject: 19999 Mathematical Sciences not elsewhere classified
subject: FOS: Mathematics
subject: Cancer
subject: Inorganic Chemistry
subject: FOS: Chemical sciences
subject: Plant Biology
subject: Computational Biology

description: Estimating phylogenetic trees is an important problem in evolutionary biology, environmental policy, and medicine. Although trees are estimated, their uncertainties are generally discarded in statistical models for tree-valued data. Here, we explicitly model the multivariate uncertainty of tree estimates. We consider both the cases where uncertainty information arises extrinsically (through covariate information) and intrinsically (through the tree estimates themselves). The latter case is applicable to any procedure for tree estimation, and thus has broad relevance to the entire field of phylogenetics. The importance of accounting for tree uncertainty in tree space is demonstrated in two case studies. In the first instance, differences between gene trees are small relative to their uncertainties, while in the second, the differences are relatively large. Our main goal is visualization of tree uncertainty, and we demonstrate advantages of our method with respect to reproducibility, speed, and preservation of topological differences compared to visualization based on multidimensional scaling. The proposal highlights that phylogenetic trees are estimated in an extremely high-dimensional space, resulting in uncertainty information that cannot be discarded. Most importantly, it is a method that allows biologists to diagnose whether differences between gene trees are biologically meaningful or due to uncertainty in estimation.
COMPRESSED LEARNING FOR TEXT CATEGORIZATION
Creators: name: Ferreira, Artur
name: Figueiredo, Mario
Publisher: name: ISEL - High Institute of Engineering of Lisbon
Year: 2013
Subjects: random projections, random subspaces, compressed learning, text classification, support vector machines

description: In text classification based on the bag-of-words (BoW) or similar representations, we usually have a large number of features, many of which are irrelevant (or even detrimental) for classification tasks. Recent results show that compressed learning (CL), i.e., learning in a domain of reduced dimensionality obtained by random projections (RP), is possible, and theoretical bounds on the test set error rate have been shown. In this work, we assess the performance of CL, based on RP of BoW representations for text classification. Our experimental results show that CL significantly reduces the number of features and the training time, while simultaneously improving the classification accuracy. Rather than the mild decrease in accuracy upper bounded by the theory, we actually find an increase of accuracy. Our approach is further compared against two techniques, namely the unsupervised random subspaces method and the supervised Fisher index. The CL approach is suited for unsupervised or semi-supervised learning, without any modification, since it does not use the class labels.
description: i-ETC : ISEL Academic Journal of Electronics Telecommunications and Computers, Vol 2, No 1 (2013): The CETC2011 Issue