cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
New "Einstein Cross" Gravitational Lens Candidates in HST WFPC2 Survey Images
Creators: name: Ratnatunga, Kavan U.
name: Ostrander, Eric J.
name: Griffiths, Richard E.
name: Im, Myungshin
Publisher: name: arXiv
Year: 1995
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We report the serendipitous discovery of ``Einstein cross'' gravitational lens candidates using the Hubble Space Telescope. We have so far discovered two good examples of such lenses, each in the form of four faint blue images located in a symmetric configuration around a red elliptical galaxy. The high resolution of HST has facilitated the discovery of this optically selected sample of faint lenses with small (~1 arcsec) separations between the (I ~ 25-27) lensed components and the much brighter (I ~ 19-22) lensing galaxies. The sample has been discovered in the routine processing of HST fields through the Medium Deep Survey pipeline, which fits simple galaxy models to broad band filter images of all objects detected in random survey fields using WFPC2. We show that the lens configuration can be modeled using the gravitational field potential of a singular isothermal ellipsoidal mass distribution. With this model the lensing potential is very similar, both in ellipticity and orientation, to the observed light distribution of the elliptical galaxy, as would occur when stars are a tracer population. The model parameters and associated errors have been derived by 2-dimensional analysis of the observed images. The maximum likelihood procedure iteratively converges simultaneously on the model for the lensing elliptical galaxy and the source of the lensed components. A systematic search is in progress for other gravitational lens candidates in the HST Medium Deep Survey. This should eventually lead to a good statistical estimate for lensing probabilities, and enable us to probe the cosmological component of the observed faint blue galaxy population.
description: Accepted for Astrophysical Journal Letters, 1995 November 1 LaTex, 10 pages, includes 2 figures 1 table, tarred gzip uuencoded using uufiles script
How a nonassociative algebra reflects the properties of a skew polynomial
Creators: name: Brown, Christian
name: Pumpluen, Susanne
Publisher: name: arXiv
Year: 2018
Subjects: subject: Rings and Algebras (math.RA)
subject: FOS: Mathematics
subject: 16S36 (Primary), 17A60, 17A99 (Secondary)

description: Let $S$ be a unital associative ring and $S[t;σ,δ]$ be a skew polynomial ring, where $σ$ is an injective endomorphism of $S$ and $δ$ a left $σ$-derivation. For each $f\in S[t;σ,δ]$ of degree $m>1$ with a unit as leading coefficient, we construct a unital nonassociative algebra whose behaviour reflects the properties of $f$. The algebras obtained yield canonical examples of right division algebras when $f$ is irreducible. We investigate the structure of these algebras. The structure of their right nucleus depends on the choice of $f$. In the classical literature, this nucleus appears as the eigenspace of $f$, and is used to investigate the irreducible factors of $f$. We give necessary and sufficient criteria for skew polynomials of low degree to be irreducible.
description: 24 pages, most of the work is part of the first author's PhD thesis (arXiv:1806.00822). Changes to first version: Section 3 has been taken out
Emergence of H7 highly pathogenic avian influenza virus from low pathogenicity avian influenza virus
Creators: name: Seekings, Amanda Hanna
Publisher: name: Imperial College London
Year: 2017

description: Outbreaks of highly pathogenic avian influenza virus (HPAIV) may result in the infection of millions of poultry, causing devastating disease and up to 100% mortality. Avian influenza outbreaks and laboratory experiments have shown that HPAIV can emerge from low pathogenicity avian influenza virus (LPAIV) precursors. The multi-basic cleavage site (MBCS) in the haemagglutinin protein is described as the main pathogenic determinant of HPAIV infection in poultry. Identifying a precursor LPAIV is important for understanding the molecular changes involved in the emergence of HPAIV. In 2008, H7N7 HPAIV was confirmed in Oxfordshire, UK. The presence of a LPAIV precursor with a rare di-basic cleavage site (DBCS) was identified. The DBCS contains an additional basic amino acid compared to common circulating LPAIVs that harbour a single basic amino acid at the cleavage site (SBCS). Using reverse genetics, isogenic viruses based on A/chicken/England/11406/2008 H7N7 HPAIV, from the outbreak, were rescued with the MBCS replaced with either a DBCS (H7N7DB) as seen in the putative LPAIV precursor or a SBCS representative of common H7 LPAIVs (H7N7SB). Intravenous pathogenicity index testing of the recombinant viruses confirmed that only the MBCS conferred the highly pathogenic phenotype. Following passage in ovo, H7N7DB showed evidence of spontaneous evolution to a HPAIV genotype and phenotype as demonstrated by the acquisition of a MBCS, and by influenza virus-specific immunohistochemistry staining in embryo vascular endothelial cells. In contrast, deep sequencing of tissues from embryos in which H7N7SB was serially passaged up to three times showed retention of the LPAIV genotype. Thus, in chicken embryos, an H7N7 virus containing a DBCS displays an unstable nature allowing for rapid evolution to HPAIV. In ovo passage presents a novel approach to assess the likelihood of a LPAIV to evolve into HPAIV, and allows a laboratory-based dissection of molecular mechanisms behind the emergence of HPAIV.
Curvature of the Riemann Zeta Modulus Near the Critical Line
Creators: name: Fernandes, Ricardo Miguel Machado
Publisher: name: Ricardo Miguel Machado Fernandes
Year: 2025
Subjects: Riemann Zeta Function
Critical Line
Curvature Analysis
Prime Number Theory
Zeta Modulus
Riemann Hypothesis

description: This study investigates the curvature of the modulus of the Riemann zeta function ∣ζ(s)∣|\zeta(s)|∣ζ(s)∣ in the critical strip. We analyze the second discrete difference of ∣ζ(σ+it)∣|\zeta(\sigma + it)|∣ζ(σ+it)∣ for t≤50,000t \leq 50,000t≤50,000 and find that curvature achieves local minima at the critical line σ=1/2\sigma = 1/2σ=1/2. This supports the idea that the critical line represents a minimal distortion path in the modulus landscape, offering a structural heuristic for understanding the special nature of the Riemann Hypothesis.
Magnetoelastic coupling and tricritical metamagnetism
Creators: name: Baumfeld, Oliver Lukas
Publisher: name: Imperial College London
Year: 2016

description: Magneto-elastic coupling plays a significant role in magnetocaloric materials for magnetic refrigeration at room temperature. It can lead to the existence of a so-called tricritical point where a metamagnetic phase transition changes from first order to second order. Controlling tricriticallity allows us to control the hysteresis of the metamagnetic transition which is of relevance for cyclic application of a magnetic field in a cooling device. This thesis investigates the two incommensurate antiferromagnets CoMnSi and NiMn(Ge,Si) by means of powder neutron diffraction and magnetisation measurements. The correlation between structural parameters and the magnetic structure is established. In CoMnSi a very broad magneto-elastic phase transition is found to go hand in hand with the changes in thermomagnetic hysteresis and a new cycloidal ground state is proposed. In NiMn(Ge,Si) a first order transition between two antiferromagnetic states in zero field is responsible for the changes in the metamagnetic critical field. The antiferromagnetic exchange interaction decreases with the silicon content and it is found that this is correlated with a decrease in the strength of the magneto-elastic coupling. Furthermore this thesis investigates the peak splitting in the metamagnet La(Fe,Si)13H due to hydrogen diffusion which is a direct consequence of strong magneto-volume coupling. By means of time- and temperature-dependent magnetisation measurements the diffusion constant D is estimated to be approximately between 10E-15 and 10E-16 m^2s^-1 at room temperature. It is shown that the thermodynamic driving force behind hydrogen diffusion and phase segregation may be attributed to the lower free energy of hydrogen interstitials in the ferromagnetic state relative to the paramagnetic state.
Fourier Power Function Shapelets (FPFS) Shear Estimator: Performance on Image Simulations
Creators: name: Li, Xiangchong
name: Katayama, Nobuhiko
name: Oguri, Masamune
name: More, Surhud
Publisher: name: arXiv
Year: 2018
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We reinterpret the shear estimator developed by Zhang & Komatsu (2011) within the framework of Shapelets and propose the Fourier Power Function Shapelets (FPFS) shear estimator. Four shapelet modes are calculated from the power function of every galaxy's Fourier transform after deconvolving the Point Spread Function (PSF) in Fourier space. We propose a novel normalization scheme to construct dimensionless ellipticity and its corresponding shear responsivity using these shapelet modes. Shear is measured in a conventional way by averaging the ellipticities and responsivities over a large ensemble of galaxies. With the introduction and tuning of a weighting parameter, noise bias is reduced below one percent of the shear signal. We also provide an iterative method to reduce selection bias. The FPFS estimator is developed without any assumption on galaxy morphology, nor any approximation for PSF correction. Moreover, our method does not rely on heavy image manipulations nor complicated statistical procedures. We test the FPFS shear estimator using several HSC-like image simulations and the main results are listed as follows. (i) For simulations which only contain isolated galaxies, the amplitude of multiplicative bias is below 1 % . (ii) For more realistic simulations which also contain blended galaxies, the blended galaxies are deblended by the first generation HSC deblender before shear measurement. Multiplicative bias of (-5.71 +- 0.31) % is found. The blending bias is calibrated by image simulations. Finally, we test the consistency and stability of this calibration.
description: 18 pages, 3 figures, accepted by MNRAS
Acute and chronic effects of anti-cancer agents on cardiac mitochondrial function
Creators: name: Elder, Jessica Maeve
Publisher: name: Imperial College London
Year: 2017

description: Cardiotoxicity resulting from the agents used to treat neoplastic disorders is becoming increasingly clinically relevant as cancer survival rates improve. Mitochondria are a common target and potential mediator of this toxicity. Healthy mitochondrial function is integral to both the life and death of cardiomyocytes and alterations in mitochondrial function are increasingly recognised in patients presenting with cardiomyopathy. This PhD project examined the acute and chronic effects of anti-cancer agents on the heart with a specific focus on cardiac mitochondrial function. A rat model of DOX-induced cardiomyopathy was utilised to examine the chronic effect of doxorubicin (DOX) on cardiac mitochondria. DOX-treated rats showed progressive cardiac decline with a significant reduction in ejection fraction and marked mitochondrial morphological changes. RNA sequencing of left ventricular tissue revealed that the most significantly decreased transcript levels were those related to mitochondrial function. Twenty-four hour DOX treatment of freshly isolated adult rat ventricular cardiomyocytes resulted in a significant decrease in maximal respiratory capacity and a significant increase in mitochondrial-related transcript levels. In the Langendorff-perfused rat heart DOX infusion resulted in acute progressive concentration-dependent mitochondrial membrane potential (m) dissipation. Infusion of the tyrosine kinase inhibitors sunitinib or SU14813 was also found to result in a slight dissipation of the m in the isolated rat heart. This study demonstrates that the effects of DOX on cardiac mitochondrial function are both acute and chronic and contribute significantly to the pathogenesis of DOX-induced cardiomyopathy. Overall, these findings demonstrate that mitochondrial dysfunction plays a significant role in the development of anti-cancer agent induced-cardiomyopathy and highlights mitochondria as a novel target for cardioprotection.
Is increased precipitation during the 20th century statistically or ecologically significant in the eastern US?
Creators: name: Hanberry, Brice B.
name: Abrams, Marc D.
name: White, Joseph D.
Publisher: name: Taylor & Francis
Year: 2018
Subjects: subject: Space Science
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: Ecology
subject: FOS: Biological sciences
subject: Sociology
subject: FOS: Sociology
subject: 69999 Biological Sciences not elsewhere classified
subject: Computational Biology

description: We address the climate versus disturbance debate to understand drivers of change in human-environment systems. We examine whether recent increased precipitation episodes (‘pluvials’) are unique and have ecological implications for the humid climate of the eastern United States. Robust statistical analyzes presented here indicate that the 20th century was wet, but not significantly different than other centuries during the last millennium. Statistical methods did not establish increased precipitation episodes as an unusual change that correlated with transition shifts in eastern forests during the early 20th century. Additionally, modest precipitation change was not ecologically significant enough to result in forests composed of drought-tolerant trees in the past or drought-intolerant trees currently. We conclude that fire is a parsimonious explanation for composition and structure of historical open fire-tolerant oak and pine forests. Fire exclusion was unprecedented during early 20th century and loss of this driver provides a mechanism for forest transitions.
Raman Scattering as a Selective Probe of Chiral Electronic Excitations in Bilayer Graphene
Creators: name: Riccardi, Elisa
name: Kashuba, Oleksiy
name: Cazayous, Maximilien
name: Méasson, Marie-Aude
name: Sacuto, Alain
name: Gallais, Yann
Publisher: name: arXiv
Year: 2018
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We report a symmetry resolved electronic Raman scattering (ERS) study of a bilayer graphene device under gate voltage. We show that the ERS continuum is dominated by interband chiral excitations of $A_{2}$ symmetry and displays a characteristic Pauli-blocking behavior similar to the monolayer case. Crucially, we show that non-chiral excitations make a vanishing contribution to the Raman cross-section due to destructive interference effects in the Raman amplitude matrix elements. This is in a marked contrast to optical absorption measurements and opens interesting venues for the use of Raman scattering as a selective probe of chiral degrees of freedom in topological matter and other 2D crystals.
A Multi-Species Model for Hydrogen and Helium Absorbers in Lyman-Alpha Forest Clouds
Creators: name: Zhang, Yu
name: Anninos, Peter
name: Norman, Michael L.
Publisher: name: arXiv
Year: 1995
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We have performed a multi-species hydrodynamical simulation of the formation and evolution of Lyman alpha clouds in a flat CDM dominated universe with an external flux of ionizing radiation. We solve the fully coupled non-equilibrium rate equations for the following species: H, H^+, H^-, H_2, H_2^+, He, He^+, He^{++}, and e^-. The statistical properties of the distribution and evolution of both hydrogen and helium absorption lines are extracted and compared to observed data. We find excellent agreement for the following neutral hydrogen data: the distribution of column densities is fit well by a power law with exponent beta=1.55 with a possible deficiency of lines above column density 10^{15} cm^{-2}; the integrated distribution matches observed data over a broad range of column densities 10^{13} to 10^{17} cm^{-2}; a Gaussian statistical fit to the Doppler parameter distribution yields a median of 35.6 km s^{-1}; the evolution of the number of clouds with column densities larger than 10^{14} cm^{-2} follows a power law with exponent gamma=2.22. Analogous calculations are presented for HeII absorption lines and we find the ratio of Doppler parameters b_{HeII}/b_{HI} = 0.87. Our data also suggests that Ly$α$ clouds may belong to two morphologically different groups: small column density clouds which tend to reside in sheets or filamental structures and are very elongated and/or flattened, and the large column density clouds which are typically found at the intersections of these caustic structures and are quasi-spherical.
description: 14 pages, 4 postscript figures
Point and planar defects in titanium
Creators: name: Ready, Adam
Publisher: name: Imperial College London
Year: 2017

description: Titanium alloys are used in the aerospace industry due to their high strength, low density, and corrosion resistance. Despite all of these virtues their use is hampered by a failure mechanism called cold dwell fatigue (CDF), which can reduce the lifetime of susceptible alloys by a factor of 10. The plastic deformation leading to CDF failure is caused by creep at stresses as low as 60% of the yield stress and at temperatures as low 15% of the melting point of Ti. This 'cold creep' is the result of the planar glide of dislocations in the hexagonal close-packed or alpha-phase of Ti. Slip is the primary deformation mechanism for Ti and its alloys, so there is an inherent interest in the slip behaviour of alpha-Ti. Motivated by this I computed the entire first-order pyramidal gamma-surface for alpha-Ti using density functional theory (DFT) simulations. I found one low energy and one high energy stacking fault with energies of 163 and 681 mJ/m2, respectively. In contrast with previous suggestions, I found no stable stable stacking fault at (c + a)/2. I computed this surface using two different pseudopotentials with 4 and 12 valence states, showing that the 4 state pseudopotential adequately reproduces the results of the 12 state pseudopotential. At the time of writing the mechanism controlling cold creep, and hence CDF is unknown. One observation for helping to understand CDF is that the Ti alloy Ti-6Al-2Sn-4Zr-2Mo is highly susceptible to CDF failure but Ti-6Al-2Sn-4Zr-6Mo is not. The main difference between these alloys is 4 weight percent Mo. Motivated by this observation and using DFT simulations I investigated a hypothesis that Mo traps vacancies in alpha grains thus reducing the creep relaxation that exacerbates the conditions leading to CDF failure. Based on my results I found no support for this hypothesis.
Functional characterization of LRWD1 as a regulator of chromatin replication
Creators: name: Mirabella, Anne
Publisher: name: Imperial College London
Year: 2016

description: In eukaryotes chromatin function and organisation is defined and mediated by the recognition of DNA and histone modifications, possibly in combinatorial patterns. Cell cycle progression, chromatin organisation and DNA replication are linked and depend on one another. However, the mechanism by which these biological processes are inter-regulated is yet far from clear. The origin recognition complex (ORC) is responsible for the initiation of DNA replication and plays an important role in cell cycle progression. Through nucleosome affinity purifications, LRWD1 (Leucine rich repeat and WD repeat domain containing 1 protein) has been identified as a novel ORC interacting protein. Since, LRWD1 has been shown to act as an adaptor that mediate ORC binding to chromatin. We have characterised the function of LRWD1 from different angles by investigating how LRWD1 might be regulated by phoshorylation, by uncovering interacting partners of LRWD1 and by studying how LRWD1 interacts with differentially modified nucleosomes. We report here evidence that phosphorylation of LRWD1 might be involved in regulating the localisation of the protein in the cell potentially by altering a nuclear localisation sequence (NLS). Indeed, stable cell lines expressing phospho-mutants of LRWD1 show different distribution of LRWD1 depending on the phosphorylation status. Furthermore, proliferation defects were observed in the LRWD1 mutant cell. Investigation of LRWD1 interacting proteins in HeLa S3 cells by immunoprecipitation and mass-spectrometry revealed the cohesin subunit SMC3 as an LRWD1-interacting protein. Interestingly, LRWD1 binding sites in the genome, identified by chromatin immunoprecipitation linked to high throughput sequencing (ChIP-seq) positively correlate with SMC3 binding sites. Further analysis revealed that LRWD1 binding sites are enriched at High-C contact points within topologically associating-domains and, interestingly, preferentially localise to the base of chromatin loops in a published 3C study of the CFTR locus. The data so far suggest that LRWD1 could potentially be involved in controlling DNA replication through chromatin architecture. To determine whether LRWD1 preferentially recruits ORC to differently modified nucleosomes, we expressed and purified recombinant LRWD1, ORC 2-5 and assembled modified nucleosomes and performed in vitro nucleosomes pulldowns. We were able to confirm that LRWD1 preferentially binds to repressive chromatin marks (heterochromatin) and that the binding is independent of ORC.
E-textile: A New Sensation in Textiles
Creators: name: Rumon, md abdullah al
Publisher: name: figshare
Year: 2021
Subjects: subject: 91205 Functional Materials
subject: FOS: Materials engineering
subject: 91012 Textile Technology
subject: 90699 Electrical and Electronic Engineering not elsewhere classified
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Electronic Textiles (e-textiles) are fabrics that feature electronics and interconnections woven into them, presenting physical flexibility and typical size that cannot be achieved with other existing electronic manufacturing techniques. E-textiles, refers to fabrics that can function electrically as electronics and behave physically as textiles Electronic-textile research is closely related to wearable computing research, but in many ways its own distinct field. Wearable computing explores technologies that are portable and attached to or carried on the body, but e-textile research has a slightly different focus: investigating electronic and computational technology that is imbedded into textiles. E-textile researchers strive to build devices that are as soft, flexible and comfortable as traditional cloth artifacts.image002CAGR projections from 2016-2026 for key e-textiles markets. Using Sensors provide a nervous system to detect signals, thus in a passive smart material, the existence of sensors is essential and wireless option gives the ultimate availability to measure information or to send data instantly. All over the world there is a large field to work with and characterizes key market sectors including ‘Sports & Fitness’, ‘Medical & Healthcare’, ‘Wellness’, ‘Home & Lifestyle’, ‘Industrial, commercial, military’, ‘Fashion’ and ‘Others’ (including automotive) giving more opportunities
Vultur papa Linnaeus, 1758, spec. nov.
Creators: name: Linnaeus, Carolus
Publisher: name: Laurentius Salvius
Year: 1758
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Aves
Accipitriformes
Cathartidae
Vultur
Vultur papa

description: Vultur papa [spec. nov.]
V. naribus carunculatis, vertice colloque denudato.
Vultur elegans. Edv. av. 2. t. 2.
Vultur. Alb. av. 2. p. 4. t. 4.
Habitat in India occidentali.
Obs. Vultur. Alb. av. 3. p. 1. t. 1. an femina hujus?
Caput & Collum quasi excoriata retrahere potest intra vaginam cutis plumosae colli inferioris.
description: Published as part of Linnaeus, Carolus, 1758, Systema Naturae per regna tria naturae: secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis, Stockholm :Laurentius Salvius on page 86, DOI: 10.5962/bhl.title.542, http://zenodo.org/record/3922206
Neuroprotective effect of Capsicum annuum var. abbreviatum against hydrogen peroxide-induced oxidative stress in HT22 hippocampus cells
Creators: name: Eui-Baek Byun
name: Woo-Young Park
name: Kim, Woo Sik
name: Ha-Yeon Song
name: Nak-Yun Sung
name: Eui-Hong Byun
Publisher: name: Taylor & Francis
Year: 2018
Subjects: subject: Biochemistry
subject: Cell Biology
subject: Molecular Biology
subject: Neuroscience
subject: Physiology
subject: FOS: Biological sciences
subject: Pharmacology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Ecology
subject: Science Policy
subject: Cancer

description: Phenolic compounds isolated from pepper (Capsicum annum) have been demonstrated to have neuroprotective effects, whereas the physiological properties of Capsicum annuum var. abbreviatum (CAA) have not been studied. Thus, we investigate the chemical composition and neuroprotective activity of CAA extract (CAAE) in HT22 hippocampus cells against H2O2-induced neurotoxicity. CAAE treatment resulted in a significant protection of H2O2-exposed HT22, this protection ultimately occurred through an inhibition of MDA and ROS levels and an induction of SOD activity. Furthermore, CAAE treatment reduced H202-induced apoptosis though decreasing the expression of pro-apoptotic factors (Bax, cytochrome c, and cleaved caspases-3) while increasing the expression of the anti-apoptotic factors (Bcl-2), as well as the accumulation of nucleus-Nrf2-mediated HO-1 signaling. Interestingly, CAAE has a high concentration of unique phenolic compositions (chlrogenic acid, tangeretin, etc.) than other capsicum annum extracts. Altogether, these findings suggest that CAAE can be a useful natural resource for alleviating neurodegenerative diseases. Neuroprotective effect of CAAE against H2O2-induced oxidative stress in HT22 hippocampus cells.
Composition rules for quantum processes: a no-go theorem
Creators: name: Guérin, Philippe Allard
name: Krumm, Marius
name: Budroni, Costantino
name: Brukner, Časlav
Publisher: name: arXiv
Year: 2018
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: A quantum process encodes the causal structure that relates quantum operations performed in local laboratories. The process matrix formalism includes as special cases quantum mechanics on a fixed background space-time, but also allows for more general causal structures. Motivated by the interpretation of processes as a resource for quantum information processing shared by two (or more) parties, with advantages recently demonstrated both for computation and communication tasks, we investigate the notion of composition of processes. We show that under very basic assumptions such a composition rule does not exist. While the availability of multiple independent copies of a resource, e.g. quantum states or channels, is the starting point for defining information-theoretic notions such as entropy (both in classical and quantum Shannon theory), our no-go result means that a Shannon theory of general quantum processes will not possess a natural rule for the composition of resources.
description: 9 pages, 3 figures. Published version
Deep STIS Luminosity Functions for LMC Clusters
Creators: name: Elson, R.
name: Tanvir, N.
name: Gilmore, G.
name: Johnson, R. A.
name: Beaulieu, S.
Publisher: name: arXiv
Year: 1998
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present deep luminosity functions derived from HST STIS data for three rich LMC clusters (NGC 1805, NGC 1868, and NGC 2209), and for one Galactic globular cluster (NGC 6553). All of the LMC cluster luminosity functions are roughly consistent with a Salpeter IMF or with the solar neighbourhood IMF from Kroupa, Tout & Gilmore (1993). They continue to rise at least to 0.7 Msun. NGC 1868 shows evidence for mass segregation which may be primordial. A comparison of deep luminsoisty functions for seven Galactic globulars shows that the luminosity functions are eroded at low masses by amounts that are strongly correlated with distance from the Galactic plane.
description: 4 pages, 4 embedded figures
The role of the mixed lineage leukaemia gene in haematopoiesis and leukaemogenesis
Creators: name: Meng, Yiran
Publisher: name: Imperial College London
Year: 2016

description: Mixed lineage leukaemia (MLL) is an evolutionarily conserved gene expressing a protein with histone methyltransferase activity. It was firstly identified by its role in leukaemia. MLL fusion proteins generated by chromosomal translocations are detected in over 70% of acute infant leukaemias. The mechanism by which MLL fusions induce leukaemia remains in question. Two separate theories propose that MLL fusions act either in a gain-of-function or in an MLL-dependent manner. MLL also has a role in normal haematopoiesis. In a conditional knockout mouse model where both Mll alleles are only deleted within the haematopoietic system, Mll-deficient bone marrow has impaired long-term repopulating ability. Therefore, Mll is proposed to be essential to the self-renewal ability of haematopoietic stem cells (HSCs). The studies presented here describe the development of a novel in vitro assay to rapidly screen for the effects of individual genes on HSC function. A subset of Hox genes are found to be the potential downstream targets of Mll in the control of HSC self-renewal. The work has also demonstrated that WT Mll is dispensable for the MLL-fusion-induced immortalisation of haematopoietic progenitors. This finding suggests that MLL fusion proteins have a dominant effect on the immortalisation of haematopoietic cells and that this is independent of the expression of WT Mll.
The kinematics of the warm gas in Hickson compact group of galaxies HCG 90
Creators: name: Plana, H.
name: de Oliveira, Cl. Mendes
name: Amram, P.
name: Boulesteix, J.
Publisher: name: arXiv
Year: 1998
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present kinematic observations of H$α$ emission for two early-type galaxies and one disk system, members of the Hickson compact group 90 (HCG 90) obtained with a scanning Fabry-Perot interferometer and samplings of 16 $km$ $s^{-1}$ and 1$\arcsec$. Mapping of the gas kinematics was possible to $\sim$ 2 r$_{eff}$ for the disk galaxy N7174 and to $\sim$ 1.3 r$_{eff}$ and $\sim$ 1.7 r$_{eff}$ for the early-type galaxies N7176 and N7173 respectively. Evidence for ongoing interaction was found in the properties of the warm gas of the three galaxies, some of which do not have stellar counterparts. We suggest the following evolutionary scenario for the system. H90d is the warm gas reservoir of the group in process of fueling H90b with gas. H90c and d have experienced past interaction with gas exchange. The gas acquired by H90c has already settled and relaxed but the effects of the interaction can still be visible in the morphology of the two galaxies and their stellar kinematics. This process will possibly result in a major merger.
description: 32 pages - 10 figures, Accepted for publication in Astronomical Journal
Thresholds on star formation and the chemical evolution of galactic discs: cosmochronology and the age of the galaxy
Creators: name: Chamcham, K.
name: Hendry, M. A.
Publisher: name: arXiv
Year: 1995
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: In this paper we analyse different chronometers based on the models of chemical evolution developed in Chamcham, Pitts \& Tayler (1993; hereafter CPT) and Chamcham \& Tayler (1994; hereafter CT). In those papers we discussed the ability of our models to reproduce the observed G-dwarf distribution in the solar neighbourhood, age-metallicity relation and radial chemical abundance gradients. We now examine their response to the predictions of cosmochronology. We use the recent production ratios of the actinide pairs $^{235}$U/$^{238}$U and $^{232}$Th/$^{238}$U provided by Cowan, Thielemann \& Truran (1991) and the observed abundance ratios from Anders \& Grevesse (1989) to determine the duration of nucleosynthesis in the solar neighbourhood, and thus to determine maximum likelihood estimates and confidence intervals for the infall parameter, $β$, which controls the growth rate of the disc in our models. We compare our predictions for the age of the disc with the age of the galaxy estimated from models of white dwarf cooling and from the age of globular clusters. From our statistical analysis we find that these three methods of age prediction appear to be consistent for a range of maximum likelihood values of $β$ which is in good agreement with the values considered in CPT and CT, which were found to give a good fit to the observational data examined in those papers. We also briefly consider the consistency of our results with the age of the universe predicted in different cosmological models -- a topic which we will investigate more fully in future work.
description: Latex version 3.1, 12 pages + 15 figures, MNRAS in press, replaces earlier version in which the postscript figures had become corrupted
Structural Studies of Keratin Fibres and their Protein-Lipid Matrix
Creators: name: Jirira, Nakai
Publisher: name: Imperial College London
Year: 2016

description: Keratins are one of the most abundant proteins found in mammals. They possess intrinsic properties that are as a result of their extensive and complex molecular architecture. They are physicochemically and biomechanically robust. Their complex molecular assembly is what confers them their stability. For this reason understanding their internal structure could yield essential information regarding their function and properties. In addition, quantifiable changes detected in the structure could give rise to new insights that could be exploited in the dermatologic and cosmetic industries. Their ubiquitous nature means that the fundamental biophysical understanding, could aid in the development of analogous protein-based fibrous biomaterials for a wide range of purposes. Equilibrium and time-resolved x-ray diffraction along with multinuclear natural abundance NMR (1H and 13C) techniques have been utilised to study the effect various modifications have on the structure of keratin fibres, and their associated proteins and lipids. The core structural intermediate filament units have been analysed using x-ray diffraction. The molecular mobilities of the keratin protein networks have been investigated using solid-state NMR. The intermediate filaments, which make up the internal scaffolding of keratin fibres, were found to be extremely robust and this was ascertained through lateral and axial swelling experiments. With a range of modification, the sensitive detection of protein reduction and denaturing was quantified. The hydration of lithium bromide modified keratin was found to achieve large degrees of lateral swelling without protein degradation at equilibrium. Some key findings of the research include the cooperative behaviour of the intermediate filaments and their constituent α-helical proteins, these behaved analogously upon hydration. This was observed through time-resolved hydration experiments which were carried out for the first time on human keratin fibres. In addition, the amorphous intracellular matrix within keratin fibres displayed interesting and varied polymorphic behaviour. Furthermore, the presence of two distinct lipid bilayer domains has been detected: an intracellular domain and a cuticle domain. These core findings may be applicable to other fibrous proteins, detection of distal pathological pathways and the development of analogous bio-materials.
Redefining Business Continuity for the Remote Era: Building Resilience Beyond the Traditional Office
Creators: name: Armstrong, Arthur
Publisher: name: Zenodo
Year: 2025
Subjects: business continuity
disaster management
remote work
organizational resilience
zero trust architecture
cybersecurity
psychological safety
adaptive capacity
ISO 22301
decentralized operations
strategy

description: This paper introduces the 5P Remote Resilience Model as a new framework for business continuity planning in a remote-first world. It explores how traditional continuity strategies centered on physical facilities and rigid hierarchies have been permanently disrupted by decentralized workforces, cyber threats, SaaS dependencies, and increased operational volatility. Through real-world case studies and current research, the paper offers a practical, leadership-driven roadmap for building adaptive, human-centered resilience across people, platforms, processes, protection strategies, and organizational pulse. Critical future research directions are also identified to further advance resilience theory and practice. Organizations that adapt to this new reality will lead the next era of business. Those that hesitate will be left behind.
The Hierarchy Problem and New Warped Extra Dimension
Creators: name: Guo, Bin
name: Liu, Yu-Xiao
name: Yang, Ke
name: Wei, Shao-Wen
Publisher: name: arXiv
Year: 2018
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In this paper, we propose a new mechanism with warped extra dimension to solve the hierarchy problem, which is parallel to the Randall-Sundrum (RS) brane scenario. Different from the RS scenario, the fundamental scale is TeV scale and the four-dimensional Planck scale is generated from the exponential warped extra dimension at size of a few TeV$^{-1}$. The experimental consequences of this scenario are very different from that of the RS scenario. In the explicit realization in the nonlocal gravity theory, there is a tower of spin-2 excitations with mass gap $10^{-4}\text{eV}$ and they are coupled with the gravitational scale to the standard model particles. We further discuss the possible generalizations in other modified gravity theories. The experimental consequences are similar to $(4+N)$-dimensional large extra dimension but $N$ can be a non-integer, which satisfies the experimental constraints more easily than the integer large extra dimension model.
description: 6 pages, 2 figures. Updated version. arXiv admin note: substantial text overlap with arXiv:1501.02674
Collapse of Primordial Clouds
Creators: name: Oliveira, S. R.
name: Miranda, O. D.
name: de Araujo, J. C. N.
name: Opher, R.
Publisher: name: arXiv
Year: 1998
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present here studies of collapse of purely baryonic Population III objects with masses ranging from $10M_\odot$ to $10^6M_\odot$. A spherical Lagrangian hydrodynamic code has been written to study the formation and evolution of the primordial clouds, from the beginning of the recombination era ($z_{rec} \sim 1500$) until the redshift when the collapse occurs. All the relevant processes are included in the calculations, as well as, the expansion of the Universe. As initial condition we take different values for the Hubble constant and for the baryonic density parameter (considering however a purely baryonic Universe), as well as different density perturbation spectra, in order to see their influence on the behavior of the Population III objects evolution. We find, for example, that the first mass that collapses is $8.5\times10^4M_\odot$ for $h=1$, $Ω=0.1$ and $δ_i={δρ/ ρ}=(M / M_o)^{-1/3}(1+z_{rec})^{-1}$ with the mass scale $M_o=10^{15}M_\odot$. For $M_o=4\times10^{17}M_\odot$ we obtain $4.4\times10^{4}M_\odot$ for the first mass that collapses. The cooling-heating and photon drag processes have a key role in the collapse of the clouds and in their thermal history. Our results show, for example, that when we disregard the Compton cooling-heating, the collapse of the objects with masses $>8.5\times10^4M_\odot$ occurs earlier. On the other hand, disregarding the photon drag process, the collapse occurs at a higher redshift.
description: 10 pages, MN plain TeX macros v1.6 file, 9 PS figures. Also available at http://www.iagusp.usp.br/~oswaldo (click "OPTIONS" and then "ARTICLES"). MNRAS in press
Video-based object recognition
Creators: name: Liu, Yang
Publisher: name: Imperial College London
Year: 2016

description: With the number of videos growing rapidly in modern society, automatically recognizing objects from video input becomes increasingly pressing. Videos contain abundant yet noisy information, with easily obtained video-level labels. This thesis focuses on the task of video-based object recognition. The key problem it tackles is how to effectively accumulate the useful information in a video for object recognition, especially when only the effortless video-level annotation is available. This thesis follows the classic two-step computer vision algorithm pipeline of building object representation and learning classification model. First, two novel set-of-sets representations are proposed to represent a video sequence. The respective matching schemes are also designed to make use of the proposed representations for video matching. Then, a novel algorithm, latent bi-constraint SVM (LBSVM), is proposed to learn the classification model for video-based object recognition. It consists of two new constraints and a latent variable for SVM to effectively accumulate the abundant information in a video, by selecting the useful information and filter out the noise. Finally, a weakly supervised learning algorithm is proposed for video-based object recognition, simply using the weakly annotated video-level label. The location of the target object is inferred during the training iterations, which also helps to increase the object recognition accuracy. Since there are no suitable video datasets publicly available for video-based object recognition, four video datasets are collected in the thesis to evaluate the proposed methods: Office-Instance video dataset, Office-Category video dataset, Museum video dataset and Youtube video dataset. The four video datasets not only cover different research and application scenarios, but also illustrate the evolution of my research on the problem of video-based object recognition. The experimental results on the four video datasets demonstrate the benefits of the proposed methods.
On the asymptotic behavior of the super sonic interstellar gas flow which is made by spiral density wave, propagating in rapidly rotating galaxy disk
Creators: name: Liverts, E. V.
Publisher: name: arXiv
Year: 1998
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Nonlinear solutions for the large-scale flow of interstellar gas in the presence of a spiral gravitational field have received considerable attention because this model allows to explain a lot of observations for galaxy disks. However this investigations were forced to limit by numerable analysis of the problem because of its nonlinearity. In this paper we wish to carry out the analytical expression which allows us to describe the super sonic nonlinear interstellar gas flow in rapidly rotating galaxy disk which is made by the spiral density wave. One of characteristic parameters of theory is the amplitude of spiral density wave potential corresponding to separatrix, which separates super sonic flows from flows containing the jump from super sonic flows to subsonic. We have defined the dependence of perturbing potential value, under which the galaxy shock wave appeared with respect to the parameters characterizing the gas disk (such as sound speed in gas, disk rotation speed, "spiral design" rotation speed).
description: 12 pages Latex, 2 figures, Talk given at The 15-th annual Pushchino meeting "The Modern Problems of Extragalactic Astronomy", Pushchino, May 26 - 29, 1998
Role of the activating NK cell receptor NKG2D in models of liver inflammation and tumorigenesis
Creators: name: Aires Coutinho Guedes, Joana Isabel
Publisher: name: Imperial College London
Year: 2016

description: Inflammation is a fundamental protective immune response that is now accepted as one of the hallmarks of cancer as it can provide pro-tumorigenic signals and subvert immunosurveillance. The activating receptor NKG2D, expressed on both innate and adaptive immune cells, binds to several ligands expressed by target cells and it is known to be critical in the surveillance of ligand-expressing spontaneous tumours. NKG2D has recently emerged as an important player in inflammatory disorders but its precise relevance in inflammation-driven cancer remains elusive. In this study, the role played by NKG2D in a chemically induced model of hepatocellular carcinoma (HCC) is addressed by using NKG2D-deficient mice to provide evidence of a novel and unexpected role for NKG2D as a tumour promoter. The study shows that the presence of NKG2D in this model accelerates tumour growth, favours the recruitment of CD8+T cells to the inflamed liver tissue and exacerbates the pro-inflammatory milieu. NKG2D contributes to liver damage that drives chronic cycles of hepatocyte death and proliferation favouring tumour progression. The NKG2D/NKG2D ligand pathway provides an additional mechanism linking chronic inflammation to tumour development in the context of HCC exposing the need to selectively target the types of cancer that will benefit from NKG2D-based immunotherapy. In contrast with the HCC model, a NKG2D effect is not observed at early stages of liver inflammation in a short-term model of acute inflammation and liver damage. Mechanisms that regulate the recruitment and location of immune cells at sites of inflammation are poorly understood and no data are available regarding the importance of activating receptors in this mobilization process. For this reason a protocol for real time imaging of natural killer (NK) cells in the liver tissue using intravital confocal or two-photon laser-scanning microscopy (TPSLM) was established to address NK cell dynamics in vivo in the liver.
Stepwise oral immunotherapy for 10 days in an egg-white allergy mouse model did not ameliorate the severity of allergy but induced the production of allergen-specific IgA
Creators: name: Maeta, Akihiro
name: Risako Katahira
name: Matsushima, Marin
name: Onishi, Haruka
name: Nakamura, Yu
name: Takahashi, Kyoko
Publisher: name: Taylor & Francis
Year: 2018
Subjects: subject: Genetics
subject: FOS: Biological sciences
subject: Physiology
subject: Biotechnology
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Ecology
subject: Immunology
subject: FOS: Clinical medicine
subject: 69999 Biological Sciences not elsewhere classified
subject: 19999 Mathematical Sciences not elsewhere classified
subject: FOS: Mathematics
subject: Developmental Biology
subject: Cancer

description: We examined whether the stepwise oral immunotherapy (OIT) for 10 days ameliorates the severity of allergy and the biomarkers in an allergy mouse model. The OIT could not protect anaphylaxis symptoms after allergen challenges but promote the production of antibodies, especially allergen-specific IgA. It was suggested that this OIT influenced the function of immuno response against the allergen. Abbreviations: EW: egg white; IFC: intraperitoneal food challenge; IFN-γ: interferon-γ; IL: interleukin; OVA: ovalbumin; OM: ovomucoid; OFC: oral food challenge; OIT: oral immunotherapy.