cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Accretion of sub-stellar companions as the origin of chemical abundance inhomogeneities in globular clusters
Creators: name: Winter, Andrew J.
name: Clarke, Cathie J.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Globular clusters exhibit abundance variations, defining `multiple populations', which have prompted a protracted search for their origin. Properties requiring explanation include: the high fraction of polluted stars ($\sim 40{-}90$~percent, correlated with cluster mass), the absence of pollution in young clusters and the lower pollution rate with binarity and distance from the cluster centre. We present a novel mechanism for late delivery of pollutants into stars via accretion of sub-stellar companions. In this scenario, stars move through a medium polluted with AGB and massive star ejecta, accreting material to produce companions with typical mass ratio $q\sim 0.1$. These companions undergo eccentricity excitation due to dynamical perturbations by passing stars, culminating in a merger with their host star. The accretion of the companion alters surface abundances via injected pollutant. Alongside other self-enrichment models, the companion accretion model can explain the dilution of pollutant and correlation with intra-cluster location. The model also explains the ubiquity and discreteness of the populations and correlations of enrichment rates with cluster mass, cluster age and stellar binarity. Abundance variations in some clusters can be broadly reproduced using AGB and massive binary ejecta abundances from the literature. In other clusters, some high companion mass ratios ($q\gtrsim 1$) are required. In these cases, the available mass budget necessitates a variable degree of mixing of the polluted material with the primary star, deviations from model ejecta abundances or mixing of internal burning products. We highlight the avenues of further investigation which are required to explore some of the key processes invoked in this model.
description: 29 pages, 20 figures, accepted for publication in MNRAS
A function whose graph has positive doubling measure
Creators: name: Ojala, Tuomo
name: Rajala, Tapio
Publisher: name: arXiv
Year: 2014
Subjects: subject: Classical Analysis and ODEs (math.CA)
subject: FOS: Mathematics
subject: 28A12 (Primary), 30L10 (Secondary)

description: We show that a doubling measure on the plane can give positive measure to the graph of a continuous function. This answers a question by Wang, Wen and Wen. Moreover we show that the doubling constant of the measure can be chosen to be arbitrarily close to the doubling constant of the Lebesgue measure.
description: 6 pages, 3 figures
Recruitment of DNA Damage Checkpoint Proteins to Damage in Transcribed and Nontranscribed Sequences
Creators: name: Jiang, G.
name: Sancar, A.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2006

description: We developed a chromatin immunoprecipitation method for analyzing the binding of repair and checkpoint proteins to DNA base lesions in any region of the human genome. Using this method, we investigated the recruitment of DNA damage checkpoint proteins RPA, Rad9, and ATR to base damage induced by UV and acetoxyacetylaminofluorene in transcribed and nontranscribed regions in wild-type and excision repair-deficient human cells in G1 and S phases of the cell cycle. We find that all 3 damage sensors tested assemble at the site or in the vicinity of damage in the absence of DNA replication or repair and that transcription enhances recruitment of checkpoint proteins to the damage site. Furthermore, we find that UV irradiation of human cells defective in excision repair leads to phosphorylation of Chk1 kinase in both G1 and S phase of the cell cycle, suggesting that primary DNA lesions as well as stalled transcription complexes may act as signals to initiate the DNA damage checkpoint response.
Spatially Coupled LDPC Codes Constructed from Protographs
Creators: name: Mitchell, David G. M.
name: Lentmaier, Michael
name: Costello, Daniel J.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: In this paper, we construct protograph-based spatially coupled low-density parity-check (SC-LDPC) codes by coupling together a series of L disjoint, or uncoupled, LDPC code Tanner graphs into a single coupled chain. By varying L, we obtain a flexible family of code ensembles with varying rates and frame lengths that can share the same encoding and decoding architecture for arbitrary L. We demonstrate that the resulting codes combine the best features of optimized irregular and regular codes in one design: capacity approaching iterative belief propagation (BP) decoding thresholds and linear growth of minimum distance with block length. In particular, we show that, for sufficiently large L, the BP thresholds on both the binary erasure channel (BEC) and the binary-input additive white Gaussian noise channel (AWGNC) saturate to a particular value significantly better than the BP decoding threshold and numerically indistinguishable from the optimal maximum a-posteriori (MAP) decoding threshold of the uncoupled LDPC code. When all variable nodes in the coupled chain have degree greater than two, asymptotically the error probability converges at least doubly exponentially with decoding iterations and we obtain sequences of asymptotically good LDPC codes with fast convergence rates and BP thresholds close to the Shannon limit. Further, the gap to capacity decreases as the density of the graph increases, opening up a new way to construct capacity achieving codes on memoryless binary-input symmetric-output (MBS) channels with low-complexity BP decoding.
description: Submitted to the IEEE Transactions on Information Theory
First Observations of the Brown Dwarf HD 19467 B with JWST
Creators: name: Greenbaum, Alexandra Z.
name: Llop-Sayson, Jorge
name: Lew, Ben
name: Bryden, Geoffrey
name: Roellig, Thomas
name: Ygouf, Marie
name: Fulton, B. J.
name: Hey, Daniel R.
name: Huber, Daniel
name: Mukherjee, Sagnick
name: Meyer, Michael
name: Leisenring, Jarron
name: Rieke, Marcia
name: Boyer, Martha
name: Green, Joseph J.
name: Kelly, Doug
name: Misselt, Karl
name: Serabyn, Eugene
name: Stansberry, John
name: Chu, Laurie E. U.
name: De Furio, Matthew
name: Johnstone, Doug
name: Schlieder, Joshua E.
name: Beichman, Charles
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: We observed HD 19467 B with JWST's NIRCam in six filters spanning 2.5-4.6 $μm$ with the Long Wavelength Bar coronagraph. The brown dwarf HD 19467 B was initially identified through a long-period trend in the radial velocity of G3V star HD 19467. HD 19467 B was subsequently detected via coronagraphic imaging and spectroscopy, and characterized as a late-T type brown dwarf with approximate temperature $\sim1000$K. We observed HD 19467 B as a part of the NIRCam GTO science program, demonstrating the first use of the NIRCam Long Wavelength Bar coronagraphic mask. The object was detected in all 6 filters (contrast levels of $2\times10^{-4}$ to $2\times10^{-5}$) at a separation of 1.6 arcsec using Angular Differential Imaging (ADI) and Synthetic Reference Differential Imaging (SynRDI). Due to a guidestar failure during acquisition of a pre-selected reference star, no reference star data was available for post-processing. However, RDI was successfully applied using synthetic Point Spread Functions (PSFs) developed from contemporaneous maps of the telescope's optical configuration. Additional radial velocity data (from Keck/HIRES) are used to constrain the orbit of HD 19467 B. Photometric data from TESS are used to constrain the properties of the host star, particularly its age. NIRCam photometry, spectra and photometry from literature, and improved stellar parameters are used in conjunction with recent spectral and evolutionary substellar models to derive physical properties for HD 19467 B. Using an age of 9.4$\pm$0.9 Gyr inferred from spectroscopy, Gaia astrometry, and TESS asteroseismology, we obtain a model-derived mass of 62$\pm 1M_{J}$, which is consistent within 2-$σ$ with the dynamically derived mass of 81$^{+14}_{-12}M_{J}$.
description: 21 pages, 19 figures. Accepted to AAS Journals
Role of p38 in Replication of Trypanosoma brucei Kinetoplast DNA
Creators: name: Englund, P. T.
name: Liu, B.
name: Griffith, J. D.
name: Pandey, A.
name: Molina, H.
name: Kalume, D.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2006

description: Trypanosomes have an unusual mitochondrial genome, called kinetoplast DNA, that is a giant network containing thousands of interlocked minicircles. During kinetoplast DNA synthesis, minicircles are released from the network for replication as θ-structures, and then the free minicircle progeny reattach to the network. We report that a mitochondrial protein, which we term p38, functions in kinetoplast DNA replication. RNA interference (RNAi) of p38 resulted in loss of kinetoplast DNA and accumulation of a novel free minicircle species named fraction S. Fraction S minicircles are so underwound that on isolation they become highly negatively supertwisted and develop a region of Z-DNA. p38 binds to minicircle sequences within the replication origin. We conclude that cells with RNAi-induced loss of p38 cannot initiate minicircle replication, although they can extensively unwind free minicircles.
Exciton complexes in low dimensional transition metal dichalcogenides
Creators: name: Thilagam, A.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We examine the excitonic properties of layered configurations of low dimensional transition metal dichalcogenides (LTMDCs) using the fractional dimensional space approach. The binding energies of the exciton, trion and biexciton in LTMDCs of varying layers are analyzed, and linked to the dimensionality parameter $α$, which provides insight into critical electro-optical properties (relative oscillator strength, absorption spectrum, exciton-exciton interaction) of the material systems. The usefulness of $α$ is highlighted by its independence of the physical mechanisms underlying the confinement effects of geometrical structures. Our estimates of the binding energies of exciton complexes for the monolayer configuration of transition metal dichalcogenides suggest a non-collinear structure for the trion and a positronium-molecule-like square structure for the biexciton.
description: 8 pages, edits
title: Trauma informed care for adverse childhood experiences among out-of-home-care children - developing an understanding through case studies from India
Creators: name: Modi, Kiran
name: Hai, Kakul
Publisher: name: Strathprints - University of Strathclyde
Year: 2019

description: The Adverse Childhood Experiences (ACE) model propagates a life perspective where children exposed to traumatic and stressful experiences during childhood tend to grow up with social, emotional and behavioural difficulties, leading them to adopt health-risk behaviours that cause disease, disability, and ultimately an early death. In this paper, using the ACE model, we give case studies of two Out-of-Home-Care (OHC) children, raised in Udayan Ghars, (Udayan Care's model of Child Care Institutions) describing the impact of adverse experiences on their childhood and how it shaped their lives. In the case of Sonia, her traumatic childhood led her to experience extreme social, emotional, and behavioural problems that she was unable to overcome. Priya, on the other hand, exercised resilience and despite her traumatic childhood, was able to regulate her emotions and behaviours, becoming better-adjusted. Trauma Informed Care (TIC) was used in both the girls' cases during their rehabilitation at Udayan Ghars. However, success with Priya and failure with Sonia highlights the challenges caregivers face when caring for children with extreme ACE issues.
Multi-scale and Multi-directional VLBI Imaging with CLEAN
Creators: name: Müller, Hendrik
name: Lobanov, Andrei
Publisher: name: arXiv
Year: 2023
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Very long baseline interferometry (VLBI) is a radio-astronomical technique in which the correlated signal from various baselines is combined into an image of highest angular resolution. Due to sparsity of the measurements, this imaging procedure constitutes an ill-posed inverse problem. For decades the CLEAN algorithm was the standard choice in VLBI studies, although having some serious disadvantages and pathologies that are challenged by the requirements of modern frontline VLBI applications. We develop a novel multi-scale CLEAN deconvolution method (DoB-CLEAN) based on continuous wavelet transforms that address several pathologies in CLEAN imaging. We benchmark this novel algorithm against CLEAN reconstructions on synthetic data and reanalyze BL Lac observations of RadioAstron with DoB-CLEAN. DoB-CLEAN approaches the image by multi-scalar and multi-directional wavelet dictionaries. Two different dictionaries are used. Firstly, a difference of elliptical spherical Bessel functions dictionary fitted to the uv-coverage of the observation that is used to sparsely represent the features in the dirty image. Secondly, a difference of elliptical Gaussian wavelet dictionary that is well suited to represent relevant image features cleanly. The deconvolution is performed by switching between the dictionaries. DoB-CLEAN achieves super-resolution compared to CLEAN and remedies the spurious regularization properties of CLEAN. In contrast to CLEAN, the representation by basis functions has a physical meaning. Hence, the computed deconvolved image still fits the observed visibilities, opposed to CLEAN. State-of-the-art multi-scalar imaging approaches seem to outperform single-scalar standard approaches in VLBI and are well suited to maximize the extraction of information in ongoing frontline VLBI applications.
description: Accepted for publication in A&A
Low-Dimensional Topology of Information Fusion
Creators: name: Carmi, Avishy Y.
name: Moskovich, Daniel
Publisher: name: arXiv
Year: 2014
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences
subject: H.1.1
subject: 94A15, 57M25

description: We provide an axiomatic characterization of information fusion, on the basis of which we define an information fusion network. Our construction is reminiscent of tangle diagrams in low dimensional topology. Information fusion networks come equipped with a natural notion of equivalence. Equivalent networks `contain the same information', but differ locally. When fusing streams of information, an information fusion network may adaptively optimize itself inside its equivalence class. This provides a fault tolerance mechanism for such networks.
description: 8 pages. Conference proceedings version. Will be superceded by a journal version
Targeting of C-Terminal Binding Protein (CtBP) by ARF Results in p53-Independent Apoptosis
Creators: name: Paliwal, S.
name: Pande, S.
name: Kovi, R. C.
name: Bardeesy, N.
name: Grossman, S. R.
name: Sharpless, N. E.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2006

description: ARF encodes a potent tumor suppressor that antagonizes MDM2, a negative regulator of p53. ARF also suppresses the proliferation of cells lacking p53, and loss of ARF in p53-null mice, compared with ARF or p53 singly null mice, results in a broadened tumor spectrum and decreased tumor latency. To investigate the mechanism of p53-independent tumor suppression by ARF, potential interacting proteins were identified by yeast two-hybrid screen. The antiapoptotic transcriptional corepressor C-terminal binding protein 2 (CtBP2) was identified, and ARF interactions with both CtBP1 and CtBP2 were confirmed in vitro and in vivo. Interaction with ARF resulted in proteasome-dependent CtBP degradation. Both ARF-induced CtBP degradation and CtBP small interfering RNA led to p53-independent apoptosis in colon cancer cells. ARF induction of apoptosis was dependent on its ability to interact with CtBP, and reversal of ARF-induced CtBP depletion by CtBP overexpression abrogated ARF-induced apoptosis. CtBP proteins represent putative targets for p53-independent tumor suppression by ARF.
Slip and Jump Coefficients for General Gas-Surface Interactions According to the Moment Method
Creators: name: Li, Ruo
name: Yang, Yichen
Publisher: name: arXiv
Year: 2023
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Numerical Analysis (math.NA)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We develop a moment method based on the Hermite series of arbitrary order to calculate viscous-slip, thermal-slip, and temperature-jump coefficients for general gas-surface scattering kernels. Under some usual assumptions of scattering kernels, the solvability is obtained by showing the positive definiteness of the symmetric coefficient matrix in the boundary conditions. For gas flows with the Cercignani-Lampis gas-surface interaction and inverse-power-law intermolecular potentials, the model can capture the slip and jump coefficients accurately with elegant analytic expressions. On the one hand, the proposed method can apply to the cases of arbitrary order moments with increasing accuracy. On the other hand, the explicit formulae for low-order situations are simpler and more accurate than some existing results in references. Therefore, one may apply these formulae in slip and jump conditions to improve the accuracy of macroscopic fluid dynamic models for gas flows.
ZFP100, a Component of the Active U7 snRNP Limiting for Histone Pre-mRNA Processing, Is Required for Entry into S Phase
Creators: name: Wagner, E. J.
name: Marzluff, W. F.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2006

description: Metazoan replication-dependent histone mRNAs are the only eukaryotic mRNAs that are not polyadenylated. The cleavage of histone pre-mRNA to form the unique 3′ end requires the U7 snRNP and the stem-loop binding protein (SLBP) that binds the 3′ end of histone mRNA. U7 snRNP contains three novel proteins, Lsm10 and Lsm11, which are part of the core U7 Sm complex, and ZFP100, a Zn finger protein that helps stabilize binding of the U7 snRNP to the histone pre-mRNA by interacting with the SLBP/pre-mRNA complex. Using a reporter gene that encodes a green fluorescent protein mRNA ending in a histone 3′ end and mimics histone gene expression, we demonstrate that ZFP100 is the limiting factor for histone pre-mRNA processing in vivo. The overexpression of Lsm10 and Lsm11 increases the cellular levels of U7 snRNP but has no effect on histone pre-mRNA processing, while increasing the amount of ZFP100 increases histone pre-mRNA processing but has no effect on U7 snRNP levels. We also show that knocking down the known components of U7 snRNP by RNA interference results in a reduction in cell growth and an unsuspected cell cycle arrest in early G1, suggesting that active U7 snRNP is necessary to allow progression through G1 phase to S phase.
title: Book review : Daly, A., (2018). Children, Autonomy and the Courts: Beyond the Right to be Heard
Creators: name: Porter, Robert
Publisher: name: Strathprints - University of Strathclyde
Year: 2019

description: 'Children, Autonomy and the Courts' is based upon Aoife Daly's PhD thesis, and presents her argument that Article 12 of the United Nations Convention on the Rights of the Child – which she refers to as the 'right to be heard' – does not go far enough in securing the rights of children in relation to court proceedings. In particular, Daly focuses on those proceedings where 'best interests of the child' is the paramount concern, and although there is a focus on private law, it is also of interest to those involved in child protection and welfare decision-making in public law. That this is an adaptation from a thesis is clear in the style and structure of the book. This is no reference book, nor a book that can be easily dipped into to extract particular information, but it takes the reader on a compelling journey, from illustrating the limitations of Article 12, through to the need for, and arguments in favour of, an autonomy principle, and its implementation.
ASB4 Is a Hydroxylation Substrate of FIH and Promotes Vascular Differentiation via an Oxygen-Dependent Mechanism
Creators: name: Patterson, C.
name: Ferguson, J. E.
name: Wang, H.
name: Charles, P.
name: Wu, Y.
name: Smith, K.
name: Powers, K.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2007

description: The molecular mechanisms of endothelial differentiation into a functional vascular network are incompletely understood. To identify novel factors in endothelial development, we used a microarray screen with differentiating embryonic stem (ES) cells that identified the gene for ankyrin repeat and SOCS box protein 4 (ASB4) as the most highly differentially expressed gene in the vascular lineage during early differentiation. Like other SOCS box-containing proteins, ASB4 is the substrate recognition molecule of an elongin B/elongin C/cullin/Roc ubiquitin ligase complex that mediates the ubiquitination and degradation of substrate protein(s). High levels of ASB4 expression in the embryonic vasculature coincide with drastic increases in oxygen tension as placental blood flow is initiated. However, as vessels mature and oxygen levels stabilize, ASB4 expression is quickly downregulated, suggesting that ASB4 may function to modulate an endothelium-specific response to increasing oxygen tension. Consistent with the hypothesis that ASB4 function is regulated by oxygen concentration, ASB4 interacts with the factor inhibiting HIF1α (FIH) and is a substrate for FIH-mediated hydroxylation via an oxygen-dependent mechanism. Additionally, overexpression of ASB4 in ES cells promotes differentiation into the vascular lineage in an oxygen-dependent manner. We postulate that hydroxylation of ASB4 in normoxia promotes binding to and degradation of substrate protein(s) to modulate vascular differentiation.
Effects of three-nucleon forces and two-body currents on Gamow-Teller strengths
Creators: name: Ekström, A.
name: Jansen, G. R.
name: Wendt, K. A.
name: Hagen, G.
name: Papenbrock, T.
name: Bacca, S.
name: Carlsson, B.
name: Gazit, D.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Nuclear Theory (nucl-th)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: We optimize chiral interactions at next-to-next-to leading order to observables in two- and three-nucleon systems, and compute Gamow-Teller transitions in carbon-14, oxygen-22 and oxygen-24 using consistent two-body currents. We compute spectra of the daughter nuclei nitrogen-14, fluorine-22 and fluorine-24 via an isospin-breaking coupled-cluster technique, with several predictions. The two-body currents reduce the Ikeda sum rule, corresponding to a quenching factor q^2 ~ 0.84-0.92 of the axial-vector coupling. The half life of carbon-14 depends on the energy of the first excited 1+ state, the three-nucleon force, and the two-body current.
On Measuring the 21 cm Global Spectrum of the Cosmic Dawn with an Interferometer Array
Creators: name: Zhang, Xin
name: Yue, Bin
name: Shi, Yuan
name: Wu, Fengquan
name: Chen, Xuelei
Publisher: name: arXiv
Year: 2023
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We theoretically investigate the recovery of global spectrum (monopole) from visibilities (cross-correlation only) measured by the interferometer array and the feasibility of extracting 21 cm signal of cosmic dawn. In our approach, the global spectrum is obtained by solving the monopole and higher-order components simultaneously from the visibilities measured with up to thousands of baselines. Using this algorithm, the monopole of both foreground and the 21 cm signal can be correctly recovered in a broad range of conditions. We find that a 3D baseline distribution can have much better performance than a 2D (planar) baseline distribution, particularly when there is a lack of shorter baselines. We simulate for ground-based 2D and 3D array configurations, and a cross-shaped space array located at the Sun-Earth L2 point that can form 3D baselines through orbital precession. In all simulations we obtain good recovered global spectrum, and successfully extract the 21 cm signal from it, with reasonable number of antennas and observation time.
description: 18 pages, 23 figures, accepted for publication in ApJ
(:unas) unassigned
Creators: name: (:Unkn) Unknown
Publisher: name: Universita' degli Studi di Salerno
Year: 2024

description: “Culture” can be defined as “the customs and beliefs, art, way of life and social organization of a particular country or group” (Oxford University Press, 2005). This way of life is shown in their behaviour, habits, and attitudes toward each other. The old-tradition of the caste system has divided Indian society into various sections which has given birth to socio-economic and cultural inequality. The basic features of the caste system are: ‘birth-ascription, endogamy, ritual pollution and traditional occupation’. The system has made Shudras and untouchables, the lowest castes, the victims. They are kept to the margins of society and to the majority even access to knowledge is a dream. Dalit is a self-adopted term used by this marginalized section of society. Dalit women are ‘Dalits among Dalits’ as they are the victims of caste and gender culture, hence, doubly marginalized. Film narratives as the mass media reach a large audience. Hence, these narratives are important cultural documents that present society's problems and influence the audience’s perception on a particular issue. Taking this as background the paper attempts to highlight the representation of Dalit women’s issues in selected Indian film narratives: Achhut Kanya (1936), Sujata (1959) and Article 15 (2019).
Quasiparticle Interference, quasiparticle interactions and the origin of the charge density-wave in 2H-NbSe$_{2}$
Creators: name: Arguello, C. J.
name: Rosenthal, E. P.
name: Andrade, E. F.
name: Jin, W.
name: Yeh, P. C.
name: Zaki, N.
name: Jia, S.
name: Cava, R. J.
name: Fernandes, R. M.
name: Millis, A. J.
name: Valla, T.
name: Osgood, R. M.
name: Pasupathy, A. N.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We show that a small number of intentionally introduced defects can be used as a spectroscopic tool to amplify quasiparticle interference in 2H-NbSe$_{2}$, that we measure by scanning tunneling spectroscopic imaging. We show from the momentum and energy dependence of the quasiparticle interference that Fermi surface nesting is inconsequential to charge density wave formation in 2H-NbSe$_{2}$. We demonstrate that by combining quasiparticle interference data with additional knowledge of the quasiparticle band structure from angle resolved photoemission measurements, one can extract the wavevector and energy dependence of the important electronic scattering processes thereby obtaining direct information both about the fermiology and the interactions. In 2H-NbSe$_{2}$, we use this combination to show that the important near-Fermi-surface electronic physics is dominated by the coupling of the quasiparticles to soft mode phonons at a wave vector different from the CDW ordering wave vector.
description: Main text: 13 pages, 4 figures (single column). In this version: More references included, larger figures. First version did not contained the supplementary material. This version includes the supplementary material within the same file (8 pages, 7 figures)
Jiamusi pulsar observations: IV. The core-weak pattern of PSR B0329+54
Creators: name: Wang, Tao
name: Han, J. L.
name: Wang, C.
name: Wang, P. F.
name: Zhou, D. J.
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The bright pulsar PSR B0329+54 was previously known for many years to have two emission modes. Sensitive observations of individual pulses reveal that the central component of pulse profile, which is called core component, is found to be very weakened occasionally for some periods and then recovered. This is the newly identified core-weak mode. Based on our long observations of PSR B0329+54 by the Jiamusi 66-m telescope at 2250 MHz, we report here that the profile components of individual pulses, including these for the core and the leading and trailing peaks, are relatedly varying over some periods even before and after the core-weak mode, forming a regular pattern in the phase-vs-time plot for a train of period-folded pulses. The pattern has a similar structure for the core-weak mode with a time scale of 3 to 14 periods. It starts with an intensity brightening at the trailing phase of the core component, and then the core intensity declines to a very low level, as if the core component is drifting out from the normal radiation window within one or two periods. Then the intensity for the trailing components is enhanced, and then the leading component appears at an advanced phase. Such a core-weak mode lasts for several periods. Finally, the core-weak mode ends up with an enhanced intensity at the leading phase for the core component, as if the core gradually comes back and finally stays at the phase of the profile center as it used to.
description: 10 pages, 9 figures, accepted for publication in MNRAS
Cancer-Associated Mutations in the MDM2 Zinc Finger Domain Disrupt Ribosomal Protein Interaction and Attenuate MDM2-Induced p53 Degradation
Creators: name: Jin, A.
name: White Wolf, G.
name: Lindstrom, M. S.
name: Deisenroth, C.
name: Zhang, Y.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2007

description: The p53-inhibitory function of the oncoprotein MDM2 is regulated by a number of MDM2-binding proteins, including ARF and ribosomal proteins L5, L11, and L23, which bind the central acidic domain of MDM2 and inhibit its E3 ubiquitin ligase activity. Various human cancer-associated MDM2 alterations targeting the central acidic domain have been reported, yet the functional significance of these mutations in tumor development has remained unclear. Here, we show that cancer-associated missense mutations targeting MDM2's central zinc finger disrupt the interaction of MDM2 with L5 and L11. We found that the zinc finger mutant MDM2 is impaired in undergoing nuclear export and proteasomal degradation as well as in promoting p53 degradation, yet retains the function of suppressing p53 transcriptional activity. Unlike the wild-type MDM2, whose p53-suppressive activity can be inhibited by L11, the MDM2 zinc finger mutant escapes L11 inhibition. Hence, the MDM2 central zinc finger plays a critical role in mediating MDM2's interaction with ribosomal proteins and its ability to degrade p53, and these roles are disrupted by human cancer-associated MDM2 mutations.
Conditional Deletion of Focal Adhesion Kinase Leads to Defects in Ventricular Septation and Outflow Tract Alignment
Creators: name: Smithies, O.
name: Taylor, J. M.
name: Schwartz, R. J.
name: Doherty, J. T.
name: Beggs, H. E.
name: Hakim, Z. S.
name: DiMichele, L. A.
name: Homeister, J. W.
name: Mack, C. P.
name: Brackhan, J.
name: Reichardt, L. F.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2007

description: To examine a role for focal adhesion kinase (FAK) in cardiac morphogenesis, we generated a line of mice with a conditional deletion of FAK in nkx2-5-expressing cells (herein termed FAKnk mice). FAKnk mice died shortly after birth, likely resulting from a profound subaortic ventricular septal defect and associated malalignment of the outflow tract. Additional less penetrant phenotypes included persistent truncus arteriosus and thickened valve leaflets. Thus, conditional inactivation of FAK in nkx2-5-expressing cells leads to the most common congenital heart defect that is also a subset of abnormalities associated with tetralogy of Fallot and the DiGeorge syndrome. No significant differences in proliferation or apoptosis between control and FAKnk hearts were observed. However, decreased myocardialization was observed for the conal ridges of the proximal outflow tract in FAKnk hearts. Interestingly, chemotaxis was significantly attenuated in isolated FAK-null cardiomyocytes in comparison to genetic controls, and these effects were concomitant with reduced tyrosine phosphorylation of Crk-associated substrate (CAS). Thus, it is possible that ventricular septation and appropriate outflow tract alignment is dependent, at least in part, upon FAK-dependent CAS activation and subsequent induction of polarized myocyte movement into the conal ridges. Future studies will be necessary to determine the precise contributions of the additional nkx2-5-derived lineages to the phenotypes observed.
Photoionizaton of Pure and Doped Helium Nanodroplets
Creators: name: Mudrich, M.
name: Stienkemeier, F.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Atomic and Molecular Clusters (physics.atm-clus)
subject: FOS: Physical sciences

description: Helium nanodroplets, commonly regarded as the "nearly ideal spectroscopic matrix", are being actively studied for more than two decades now. While they mostly serve as cold, weakly perturbing and transparent medium for high-resolution spectroscopy of embedded molecules, their intrinsic quantum properties such as microscopic superfluidity still are subject-matter of current research. This article reviews recent work on pure and doped He nanodroplets using PI spectroscopy, an approach which has greatly advanced in the past years. While the notion of the ideal spectroscopic matrix mostly no longer holds in this context, photoionization techniques provide detailed insights into the photo-physical properties of pure and doped He nanodroplets and their relaxation dynamics following electronic excitation. Exploiting nowadays available high laser fields, even highly ionized states of matter on the nanoscale can be formed. Our particular focus lies on recent experimental progress including fs time-resolved spectroscopy, photoion and electron imaging, and novel sources of highly energetic radiation.
description: accepted by International Reviews in Physical Chemistry
title: Book review : ACEs in the Shadows – Understanding Adverse Childhood Experiences, By A Survivor
Creators: name: Findlay, Mike
Publisher: name: Strathprints - University of Strathclyde
Year: 2019

description: I came across this book by accident when it appeared as a recommended read on Amazon. The fact the author wasn't named (A Survivor) intrigued me. I was curious as to what their motivation was for writing.
A curricular model for simulation within orthopaedic residency training
Creators: name: Schreiner, Bryan
name: Unger, Robert
Publisher: name: Oregon Health and Science University
Year: 2023
Subjects: subject: Curriculum
subject: Internship and Residency
subject: Orthopedics
subject: Assessment of learning
subject: Educational research methods and models

description: Evolving rules surrounding work hours and the clinical environment have necessitated the growth of simulation in clinical education. This curriculum comes with significant limitations, including cost, variability in training models, limited fidelity, and time. The authors aim to provide a curricular model for other orthopaedic residency programs at large academic institutions to follow as they endeavor to meet the 2013 ABOS simulation mandate.
title: الأنباط ومنطقة الخليج العربي/ د. زياد السلامين.
Creators: name: السلامين، زياد.
Publisher: name: الأرشيف والمكتبة الوطنية
Year: 2015
Subjects: الأنباط - تاريخ - الإمارات العربية المتحدة - مليحة(الشارقة) - 300ق.م.-106م
الخليج العربي - تاريخ - الأنباط.
الأنباط - تاريخ - الخليج العربي - 300ق.م.-106م

تبحث هذه الدراسة العلاقات التاريخية والحضارية بين المملكة النبطية (300ق.م-106م) ومنطقة الخليج العربي- التي كانت قائمة على التجارة؛ إذ تشير الشواهد الآثارية المكتشفة إلى وجود علاقات نبطية مباشرة مع هذه المنطقة التي يبدو أنها كانت بوابة الأنباط إلى شبه القارة الهندية. ويبدو جلياً أن منطقة الخليج العربي كانت منفتحة على العالم المحيط بها في العصور القديمة؛ فتواصلت مع الهند وبلاد فارس، والعالمين اليوناني والروماني وبلاد الشام، وكان للأنباط حضور قوي فيها. وتبين هذه الدراسة طبيعة العلاقات النبطية مع العديد من المراكز الحضارية في الجهة الشرقية من شبه الجزيرة العربية عامة، ومنطقة الخليج العربي عامة.
Review of evidence relating to occupational exposure limits for alpha-diketones and acetoin, and considerations for deriving an occupational exposure limit for 2,3-pentanedione
Creators: name: Card, Jeffrey W.
name: Scaife, Kevin M.
name: Haighton, Lois A.
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Biochemistry
subject: Medicine
subject: Genetics
subject: FOS: Biological sciences
subject: Physiology
subject: Biotechnology
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: Immunology
subject: FOS: Clinical medicine
subject: 69999 Biological Sciences not elsewhere classified
subject: Science Policy

description: Alpha-diketones, notably diacetyl, have been used as flavoring agents. When airborne in occupational settings, exposures to diacetyl have been associated with serious respiratory disease. Other α-diketones, such as 2,3-pentanedione, and analogues such as acetoin (a reduced form of diacetyl), require evaluation, particularly, in light of recently available toxicological studies. The current work reviewed mechanistic, metabolic, and toxicology data available for α-diketones. Data were most available for diacetyl and 2,3-pentanedione, and a comparative assessment of their pulmonary effects was performed, and an occupational exposure limit (OEL) was proposed for 2,3-pentanedione. Previous OELs were reviewed and an updated literature search was performed. Respiratory system histopathology data from 3-month toxicology studies were evaluated with benchmark dose (BMD) modelling of sensitive endpoints. This demonstrated comparable responses at concentrations up to 100 ppm, with no consistent overall pattern of greater sensitivity to either diacetyl or 2,3-pentanedione. In contrast, based on draft raw data, no adverse respiratory effects were observed in comparable 3-month toxicology studies that evaluated exposure to acetoin at up to 800 ppm (highest tested concentration), indicating that acetoin does not present the same inhalation hazard as diacetyl or 2,3-pentanedione. To derive an OEL for 2,3-pentanedione, BMD modelling was conducted for the most sensitive endpoint from 90-day inhalation toxicity studies, namely, hyperplasia of nasal respiratory epithelium. On the basis of this modelling, an 8-hour time-weighted average OEL of 0.07 ppm is proposed to be protective against respiratory effects that may be associated with chronic workplace exposure to 2,3-pentanedione.
cPGES/p23 Is Required for Glucocorticoid Receptor Function and Embryonic Growth but Not Prostaglandin E2 Synthesis
Creators: name: Koller, B. H.
name: Lovgren, A. K.
name: Kovarova, M.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2007

description: A number of studies have identified cytosolic prostaglandin E2 synthase (cPGES)/p23 as a cytoplasmic protein capable of metabolism of prostaglandin E2 (PGE2) from the cyclooxygenase metabolite prostaglandin endoperoxide (PGH2). However, this protein has also been implicated in a number of other pathways, including stabilization of the glucocorticoid receptor (GR) complex. To define the importance of the functions assigned to this protein, mice lacking detectible cPGES/p23 expression were generated. cPGES/p23−/− pups die during the perinatal period and display retarded lung development reminiscent of the phenotype of GR-deficient neonates. Furthermore, GR-sensitive gluconeogenic enzymes are not induced in the prenatal period. However, unlike GR-deficient embryos, cPGES/p23−/− embryos are small and a proliferation defect is observed in cPGES/p23−/− fibroblasts. Analysis of arachidonic acid metabolites in embryonic tissues and primary fibroblasts failed to support a function for this protein in PGE2 biosynthesis. Thus, while the growth retardation of the cPGES/p23−/− pups and decreased proliferation of primary fibroblasts identify functions for this protein in addition to GR stabilization, it is unlikely that these functions include metabolism of PGH2 to PGE2.
Demethylation of Histone H3K36 and H3K9 by Rph1: a Vestige of an H3K9 Methylation System in Saccharomyces cerevisiae?
Creators: name: Tempst, P.
name: Klose, R. J.
name: Erdjument-Bromage, H.
name: Zhang, Y.
name: Gardner, K. E.
name: Liang, G.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2007

description: Histone methylation is an important posttranslational modification that contributes to chromatin-based processes including transcriptional regulation, DNA repair, and epigenetic inheritance. In the budding yeast Saccharomyces cerevisiae, histone lysine methylation occurs on histone H3 lysines 4, 36, and 79, and its deposition is coupled mainly to transcription. Until recently, histone methylation was considered to be irreversible, but the identification of histone demethylase enzymes has revealed that this modification can be dynamically regulated. In budding yeast, there are five proteins that contain the JmjC domain, a signature motif found in a large family of histone demethylases spanning many organisms. One JmjC-domain-containing protein in budding yeast, Jhd1, has recently been identified as being a histone demethylase that targets H3K36 modified in the di- and monomethyl state. Here, we identify a second JmjC-domain-containing histone demethylase, Rph1, which can specifically demethylate H3K36 tri- and dimethyl modification states. Surprisingly, Rph1 can remove H3K9 methylation, a histone modification not found in budding yeast chromatin. The capacity of Rph1 to demethylate H3K9 provides the first indication that S. cerevisiae may have once encoded an H3K9 methylation system and suggests that Rph1 is a functional vestige of this modification system.
A discontinuous Galerkin method on kinetic flocking models
Creators: name: Tan, Changhui
Publisher: name: arXiv
Year: 2014
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics
subject: 65M60, 92C45

description: We study kinetic representations of flocking models. They arise from agent-based models for self-organized dynamics, such as Cucker-Smale and Motsch-Tadmor models. We prove flocking behavior for the kinetic descriptions of flocking systems, which indicates a concentration in velocity variable in infinite time. We propose a discontinuous Galerkin method to treat the asymptotic $δ$-singularity, and construct high order positive preserving scheme to solve kinetic flocking systems.
Tomography of a solar plage with the Tenerife Inversion Code
Creators: name: Li, Hao
name: Alemán, T. del Pino
name: Bueno, J. Trujillo
name: Ishikawa, R.
name: Ballester, E. Alsina
name: McKenzie, David E.
name: Auchère, Frédéric
name: Kobayashi, Ken
name: Okamoto, Takenori J.
name: Rachmeler, Laurel A.
name: Song, Donguk
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We apply the Tenerife Inversion Code (TIC) to the plage spectropolarimetric observations obtained by the Chromospheric LAyer SpectroPolarimeter (CLASP2). These unprecedented data consist of full Stokes profiles in the spectral region around the Mg II h and k lines for a single slit position, with around two thirds of the 200 arcsec slit crossing a plage region and the rest crossing an enhanced network. A former analysis of these data had allowed us to infer the longitudinal component of the magnetic field by applying the weak field approximation (WFA) to the circular polarization profiles, and to assign the inferred magnetic fields to different layers of the solar atmosphere based on the results of previous theoretical radiative transfer investigations. In this work, we apply the recently developed TIC to the same data. We obtain the stratified model atmosphere that fits the intensity and circular polarization profiles at each position along the spectrograph slit and we compare our results for the longitudinal component of the magnetic field with the previously obtained WFA results, highlighting the generally good agreement in spite of the fact that the WFA is known to produce an underestimation when applied to the outer lobes of the Mg II h and k circular polarization profiles. Finally, we use the inverted model atmospheres to give a rough estimation of the energy that could be carried by Alfvèn waves propagating along the chromosphere in the plage and network regions, showing that it is sufficient to compensate the estimated energy losses in the chromosphere of solar active regions.
description: Accepted for publication in The Astrophysical Journal
Investigation of Ultrafast Demagnetization and Gilbert Damping and their Correlation in Different Ferromagnetic Thin Films Grown Under Identical Conditions
Creators: name: Mukhopadhyay, Suchetana
name: Majumder, Sudip
name: Panda, Surya Narayan
name: Barman, Anjan
Publisher: name: arXiv
Year: 2023
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Following the demonstration of laser-induced ultrafast demagnetization in ferromagnetic nickel, several theoretical and phenomenological propositions have sought to uncover its underlying physics. In this work we revisit the three temperature model (3TM) and the microscopic three temperature model (M3TM) to perform a comparative analysis of ultrafast demagnetization in 20-nm-thick cobalt, nickel and permalloy thin films measured using an all-optical pump-probe technique. In addition to the ultrafast dynamics at the femtosecond timescales, the nanosecond magnetization precession and damping are recorded at various pump excitation fluences revealing a fluence-dependent enhancement in both the demagnetization times and the damping factors. We confirm that the Curie temperature to magnetic moment ratio of a given system acts as a figure of merit for the demagnetization time, while the demagnetization times and damping factors show an apparent sensitivity to the density of states at the Fermi level for a given system. Further, from numerical simulations of the ultrafast demagnetization based on both the 3TM and the M3TM, we extract the reservoir coupling parameters that best reproduce the experimental data and estimate the value of the spin flip scattering probability for each system. We discuss how the fluence-dependence of inter-reservoir coupling parameters so extracted may reflect a role played by nonthermal electrons in the magnetization dynamics at low laser fluences.