cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Studies on a new antimicrobial peptide from Vibrio proteolyticus MT110
Creators: name: Verma, Himanshu
name: Mihooliya, Kanti N.
name: Nandal, Jitender
name: Sahoo, Debendra K.
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Biochemistry
subject: Microbiology
subject: FOS: Biological sciences
subject: Biotechnology
subject: Environmental Sciences not elsewhere classified
subject: Chemical Sciences not elsewhere classified
subject: Ecology
subject: Immunology
subject: FOS: Clinical medicine
subject: Biological Sciences not elsewhere classified
subject: Inorganic Chemistry
subject: FOS: Chemical sciences

description: The marine environment is known for its vast diversity of the microbial population; however, less explored for bioactive compounds. In this study, an AMP produced by a new marine isolate, Vibrio proteolyticus MT110, showed broad-spectrum antimicrobial activity against Gram-positive and Gram-negative bacteria. The AMP was purified to homogeneity using ethyl acetate extraction followed by RP-HPLC, and LC-MS analysis showed its molecular weight as 980 Da. The MIC of AMP (peptide-MT110) was obtained in the 7.81–31.25 µg/mL range against different indicator strains. Peptide-MT110 showed stability of its antimicrobial activity at 15–121 °C and pH 4–10 and in the presence of various hydrolytic enzymes. The peaks at 1536 cm−1 and 1712 cm−1 wavenumbers in FTIR spectra confirmed the peptidic nature of AMP, and its amino acid analysis confirmed the presence of tyrosine and isoleucine. The antibacterial activity of peptide-MT110 is confirmed by PI assay and TEM. The optimization of peptide-MT110 production using statistical methods resulted in a 2.64-fold higher production. The physicochemical properties and stability in wide pH and temperature ranges showed the potential of peptide-MT110 for its development as a drug candidate. This is believed to be the first report on an AMP from Vibrio proteolyticus.
On the nature of bright compact radio sources at z>4.5
Creators: name: Coppejans, Rocco
name: Frey, Sándor
name: Cseh, Dávid
name: Müller, Cornelia
name: Paragi, Zsolt
name: Falcke, Heino
name: Gabányi, Krisztina É.
name: Gurvits, Leonid I.
name: An, Tao
name: Titov, Oleg
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: High-redshift radio-loud quasars are used to, among other things, test the predictions of cosmological models, set constraints on black hole growth in the early universe and understand galaxy evolution. Prior to this paper, 20 extragalactic radio sources at redshifts above 4.5 have been imaged with very long baseline interferometry (VLBI). Here we report on observations of an additional ten z>4.5 sources at 1.7 and 5 GHz with the European VLBI Network (EVN), thereby increasing the number of imaged sources by 50%. Combining our newly observed sources with those from the literature, we create a substantial sample of 30 z>4.5 VLBI sources, allowing us to study the nature of these objects. Using spectral indices, variability and brightness temperatures, we conclude that of the 27 sources with sufficient information to classify, the radio emission from one source is from star formation, 13 are flat-spectrum radio quasars and 13 are steep-spectrum sources. We also argue that the steep-spectrum sources are off-axis (unbeamed) radio sources with rest-frame self-absorption peaks at or below GHz frequencies and that these sources can be classified as gigahertz peaked-spectrum (GPS) and megahertz peaked-spectrum (MPS) sources.
description: Accepted for publication in Monthly Notices of the Royal Astronomical Society, 18 pages, 1 figure, 7 tables
Thermodynamics of shear-induced phase transition of polydisperse soft particle glasses
Creators: name: Khabaz, Fardin
name: Bonnecaze, Roger T.
Publisher: name: AIP Publishing
Year: 2021
Subjects: polydisperse

description: The thermodynamics of the shear-induced phase transition of soft particle glasses is presented. Jammed suspensions of soft particles trans- form into a layered phase in a strong shear flow from a stable glassy phase at lower shear rates. The thermodynamics of the two phases can be computed based on the elastic energy and excess entropy of the system. At a critical shear rate, the elastic energy, the excess entropy, the free energy, the temperature, and the shear stress undergo discontinuous jumps at the phase transitions from the glassy to the layered phase. An effective temperature is defined from the derivative of the elastic energy and the excess entropy. The Helmholtz free energy is constructed using the elastic energy, excess entropy, and derived temperature. At a fixed shear rate, there is no equilibrium between the states. However, at a fixed temperature, the glassy and layered states may coexist, as indicated by the equality of their Helmholtz free energies. While this first-order phase transition is possible, it cannot be observed in simple shear because the stress is the same in both phases at the same temperature. Thus, shear banding cannot be observed in this system. Finally, an equation of state, which relates the shear stress to the excess entropy, is presented. This equation of state shows that all dynamical properties (e.g., shear-induced diffusiv- ity and first and second normal stresses) of these jammed non-Brownian suspensions can be determined solely by measuring the shear stress.
The $ε$-capacity of a gain matrix and tolerable disturbances: Discrete-time perturbed linear systems
Creators: name: Zakary, O
name: Rachik, M
Publisher: name: arXiv
Year: 2016
Subjects: subject: Systems and Control (eess.SY)
subject: Classical Analysis and ODEs (math.CA)
subject: Optimization and Control (math.OC)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Mathematics

description: Discrete-time linear systems with perturbed initial state are considered. A disturbance that infects the initial state is said to be $ε$-tolerable if the corresponding output signal is relatively insensitive to their effects. In this paper, we will define a new set that characterize each gain matrix K and the associated feedback control law ui=Kxi, this set will be called the $ε$-capacity of the gain matrix K. The set of all possible gain matrix that makes the system insensitive to all disturbances is noted $Φ\cdot$. The characterization of $Φ\cdot$ is investigated, and we propose an algorithmic approach that allows to determine if a control law is belongs to $Φ\cdot$ or not. Numerical simulations are given.
description: in IOSR Journal of Electrical and Electronics Engineering, International Organization of Scientific Research (IOSR), 2015
The antibiofilm potential of a heteropolysaccharide produced and characterized from the isolated marine bacterium Glutamicibacter nicotianae BPM30
Creators: name: Trilokesh, C.
name: Harish, B. S.
name: Uppuluri, Kiran Babu
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Microbiology
subject: FOS: Biological sciences
subject: Biotechnology
subject: Chemical Sciences not elsewhere classified
subject: Ecology
subject: Immunology
subject: FOS: Clinical medicine
subject: Infectious Diseases
subject: FOS: Health sciences

description: Biofilms are the significant causes of 80% of chronic infections in the oral cavity, urinary tract, biliary tube, lungs, gastrointestinal tract, and so on to the general public. Treatment of pathogenic biofilm using bacterial exopolysaccharides (EPS) is an effective and promising strategy. In the present work, a marine bacterium was isolated, studied for exopolysaccharide production, and tested for its antibiofilm activity. Approximately 1.31 ± 0.07 g/L of a purified extracellular polysaccharide was produced and characterized from the isolated marine bacterium Glutamicibacter nicotianae BPM30. The hydrolyzed EPS contains multiple monosaccharides such as rhamnose, fructose, glucose, and galactose. The EPS demonstrated potential antibiofilm activity on four tested pathogens in a concentration-dependent mode. The antibiofilm activity of the purified EPS was studied by crystal violet assay and fluorescence staining method. Comparative inhibition results obtained for the tested strains are 93.25% ± 5.25 and 88.56% ± 2.25 for K. pneumoniae; 92.65% ± 7.6 and 98.33% ± 0.85 for P. aeruginosa; 90.36% ± 6.3 and 52.08% ± 7.74 for S. typhi; 84.62% ± 5.6 and 77.90% ± 5.90 for S. dysenteriae. The results of the present work demonstrated the antibiofilm potential of EPS, which could be helpful in the invention of novel curative approaches in battling bacterial biofilm-related medical complications.
Dynamical mass and multiplicity constraints on co-orbital bodies around stars
Creators: name: Veras, Dimitri
name: Marsh, Thomas R.
name: Gaensicke, Boris T.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Objects transiting near or within the disruption radius of both main sequence (e.g. KOI 1843) and white dwarf (WD 1145+017) stars are now known. Upon fragmentation or disintegration, these planets or asteroids may produce co-orbital configurations of nearly equal-mass objects. However, as evidenced by the co-orbital objects detected by transit photometry in the WD 1145+017 system, these bodies are largely unconstrained in size, mass, and total number (multiplicity). Motivated by potential future similar discoveries, we perform N-body simulations to demonstrate if and how debris masses and multiplicity may be bounded due to second-to-minute deviations and the resulting accumulated phase shifts in the osculating orbital period amongst multiple co-orbital equal point masses. We establish robust lower and upper mass bounds as a function of orbital period deviation, but find the constraints on multiplicity to be weak. We also quantify the fuzzy instability boundary, and show that mutual collisions occur in less than 5%, 10% and 20% of our simulations for masses of 10^{21}, 10^{22} and 10^{23} kg. Our results may provide useful initial rough constraints on other stellar systems with multiple co-orbital bodies.
description: Accepted for publication in MNRAS
Seismic Wave Amplification in 3D Alluvial Basins: 3D/1D Amplification Ratios from Fast Multipole BEM Simulations
Creators: name: Fajardo, Kristel C Meza
name: Semblat, Jean-François
name: Chaillat, Stéphanie
name: Lenti, Luca
Publisher: name: arXiv
Year: 2016
Subjects: subject: Geophysics (physics.geo-ph)
subject: FOS: Physical sciences

description: In this work, we study seismic wave amplification in alluvial basins having 3D standard geometries through the Fast Multipole Boundary Element Method in the frequency domain. We investigate how much 3D amplification differs from the 1D (horizontal layering) case. Considering incident fields of plane harmonic waves, we examine the relationships between the amplification level and the most relevant physical parameters of the problem (impedance contrast, 3D aspect ratio, vertical and oblique incidence of plane waves). The FMBEM results show that the most important parameters for wave amplification are the impedance contrast and the so-called equivalent shape ratio. Using these two parameters, we derive simple rules to compute the fundamental frequency for various 3D basin shapes and the corresponding 3D/1D amplification factor for 5% damping. Effects on amplification due to 3D basin asymmetry are also studied and incorporated in the derived rules.
Xylitol biosynthesis enhancement by Candida tropicalis via medium, process parameter optimization, and co-substrate supplementation
Creators: name: Jain, Vasundhara
name: Ghosh, Sanjoy
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Biophysics
subject: Biochemistry
subject: Space Science
subject: Cell Biology
subject: Biotechnology
subject: Chemical Sciences not elsewhere classified
subject: Biological Sciences not elsewhere classified
subject: Inorganic Chemistry
subject: FOS: Chemical sciences
subject: Plant Biology
subject: FOS: Biological sciences

description: The present study examines the impact of nitrogen sources (yeast extract, ammonium sulfate peptone, ammonium nitrate, urea, and sodium nitrate), salt solution (0.5 g/L MgSO4, 0.5 g/L KH2PO4, 0.3 g/L CaCl2), trace elements solution (0.1 g/L CuSO4, 0.1 g/L FeSO4, 0.02 g/L MnCl2, 0.02 g/L ZnSO4), operational parameters (temperature, aeration, agitation, initial pH and xylose concentration) and co- substrate supplementation (glucose, fructose, maltose, sucrose, and glycerol) on xylitol biosynthesis by Candida tropicalis ATCC 13803 using synthetic xylose. The significant medium components were identified using the Plackett Burman design followed by central composite designs to obtain the optimal concentration for the critical medium components in shaker flasks. Subsequently, the effect of operational parameters was examined using the One Factor At a Time method, followed by the impact of five co-substrates on xylitol biosynthesis in a 1 L bioreactor. The optimal media components and process parameters are as follows: peptone: 12.68 g/L, yeast extract: 6.62 g/L, salt solution (0.5 g/L MgSO4, 0.5 g/L KH2PO4, and 0.3 g/L CaCl2): 1.23 X (0.62 g/L, 0.62 g/L, and 0.37 g/L respectively), temperature: 30 °C, pH: 6, agitation: 400 rpm, aeration: 1 vvm, and xylose: 50 g/L. Optimization studies resulted in xylitol yield and productivity of 0.71 ± 0.004 g/g and 1.48 ± 0.018 g/L/h, respectively. Glycerol supplementation (2 g/L) further improved xylitol yield (0.83 ± 0.009 g/g) and productivity (1.87 ± 0.020 g/L/h) by 1.66 and 3.12 folds, respectively, higher than the unoptimized conditions thus exhibiting the potential of C. tropicalis ATCC 13803 being used for commercial xylitol production.
Intrinsic Optical and Electronic Properties from Quantitative Analysis of Plasmonic Semiconductor Nanocrystal Ensemble Optical Extinction
Creators: name: Gibbs, Stephen L.
name: Staller, Corey M.
name: Agrawal, Ankit
name: Johns, Robert W.
name: Saez Cabezas, Camila A.
name: Milliron Delia, J.
Publisher: name: The University of Texas at Austin
Year: 2020
Subjects: Nanocrystal

description: The optical extinction spectra arising from localized surface plasmon resonance in doped semiconductor nanocrystals (NCs) have intensities and lineshapes determined by free charge carrier concentrations and the various mechanisms for damping the oscillation of those free carriers. However, these intrinsic properties are convoluted by heterogeneous broadening when measuring spectra of ensembles. We reveal that the traditional Drude approximation is not equipped to fit spectra from a heterogeneous ensemble of doped semiconductor NCs and produces fit results that violate Mie scattering theory. The heterogeneous ensemble Drude approximation (HEDA) model rectifies this issue by accounting for ensemble heterogeneity and near-surface depletion. The HEDA model is applied to tin-doped indium oxide NCs for a range of sizes and doping levels but we expect it can be employed for any isotropic plasmonic particles in the quasistatic regime. It captures individual NC optical properties and their contributions to the ensemble spectra thereby enabling the analysis of intrinsic NC properties from an ensemble measurement. Quality factors for the average NC in each ensemble are quantified and found to be notably higher than those of the ensemble. Carrier mobility and conductivity derived from HEDA fits matches that measured in the bulk thin film literature.
Rossiter--McLaughlin models and their effect on estimates of stellar rotation, illustrated using six WASP systems
Creators: name: Brown, D. J. A.
name: Triaud, A. H. M. J.
name: Doyle, A. P.
name: Gillon, M.
name: Lendl, M.
name: Anderson, D. R.
name: Cameron, A. Collier
name: Hébrard, G.
name: Hellier, C.
name: Lovis, C.
name: Maxted, P. F. L.
name: Pepe, F.
name: Pollacco, D.
name: Queloz, D.
name: Smalley, B.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: We present new measurements of the projected spin--orbit angle $λ$ for six WASP hot Jupiters, four of which are new to the literature (WASP-61, -62, -76, and -78), and two of which are new analyses of previously measured systems using new data (WASP-71, and -79). We use three different models based on two different techniques: radial velocity measurements of the Rossiter--McLaughlin effect, and Doppler tomography. Our comparison of the different models reveals that they produce projected stellar rotation velocities ($v \sin I_{\rm s}$) measurements often in disagreement with each other and with estimates obtained from spectral line broadening. The Boué model for the Rossiter--McLaughlin effect consistently underestimates the value of $v\sin I_{\rm s}$ compared to the Hirano model. Although $v \sin I_s$ differed, the effect on $λ$ was small for our sample, with all three methods producing values in agreement with each other. Using Doppler tomography, we find that WASP-61\,b ($λ=4^\circ.0^{+17.1}_{-18.4}$), WASP-71\,b ($λ=-1^\circ.9^{+7.1}_{-7.5}$), and WASP-78\,b ($λ=-6^\circ.4\pm5.9$) are aligned. WASP-62\,b ($λ=19^\circ.4^{+5.1}_{-4.9}$) is found to be slightly misaligned, while WASP-79\,b ($λ=-95^\circ.2^{+0.9}_{-1.0}$) is confirmed to be strongly misaligned and has a retrograde orbit. We explore a range of possibilities for the orbit of WASP-76\,b, finding that the orbit is likely to be strongly misaligned in the positive $λ$ direction.
description: 33 pages. Accepted for publication in MNRAS
Noise-Induced Polarization Switch in Single and Multiplex Complex Networks
Creators: name: Haerter, Jan O.
name: Díaz-Guilera, Albert
name: Serrano, M. Ángeles
Publisher: name: arXiv
Year: 2016
Subjects: subject: Adaptation and Self-Organizing Systems (nlin.AO)
subject: FOS: Physical sciences

description: The combination of bistability and noise is ubiquitous in complex systems, from biological to social interactions, and has important implications for their functioning and resilience. We analyze a simple three-state model for bistability in networks under varying unbiased noise. In a fully connected network increasing noise yields a collapse of bistability to an unpolarised state. In contrast, in complex networks noise can abruptly switch the polarization state in an irreversible way. When two networks are combined through increasing multiplex coupling, one is dominant and progressively imposes its state on the other, offsetting or promoting the ability of noise to switch polarization. Our results show that dynamical correlations and asymmetry in dynamical processes in networks are sufficient for allowing unbiased noise to produce abrupt irreversible transitions between extremes, which can be neutralized or enhanced by multiplex coupling.
description: main text: 5 pages, 4 figures supplement: 15 pages, 15 figures
ALMA Observations of HD141569's Circumstellar Disk
Creators: name: White, J. A.
name: Boley, A. C.
name: Hughes, A. M.
name: Flaherty, K. M.
name: Ford, E.
name: Wilner, D.
name: Corder, S.
name: Payne, M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: We present ALMA band 7 (345 GHz) continuum and $^{12}$CO(J = 3-2) observations of the circumstellar disk surrounding HD141569. At an age of about 5 Myr, the disk has a complex morphology that may be best interpreted as a nascent debris system with gas. Our $870\rm~μm$ ALMA continuum observations resolve a dust disk out to approximately $ 56 ~\rm au$ from the star (assuming a distance of 116 pc) with $0."38$ resolution and $0.07 ~ \rm mJy~beam^{-1}$ sensitivity. We measure a continuum flux density for this inner material of $3.8 \pm 0.4 ~ \rm mJy$ (including calibration uncertainties). The $^{12}$CO(3-2) gas is resolved kinematically and spatially from about 30 to 210 au. The integrated $^{12}$CO(3-2) line flux density is $15.7 \pm 1.6~\rm Jy~km~s^{-1}$. We estimate the mass of the millimeter debris and $^{12}$CO(3-2) gas to be $\gtrsim0.04~\rm M_{\oplus}$ and $\sim2\times 10^{-3}~\rm M_{\oplus}$, respectively. If the millimeter grains are part of a collisional cascade, then we infer that the inner disk ($<50$ au) has $\sim 160~\rm M_{\oplus}$ contained within objects less than 50 km in radius, depending on the planetesimal size distribution and density assumptions. MCMC modeling of the system reveals a disk morphology with an inclination of $53.4^{\circ}$ centered around a $\rm M=2.39~ M_{\odot}$ host star ($\rm Msin(i)=1.92~ M_{\odot}$). We discuss whether the gas in HD141569's disk may be second generation. If it is, the system can be used to study the clearing stages of planet formation.
description: 35 pages, 7 figures, submitted to ApJ
The charged black-hole bomb: A lower bound on the charge-to-mass ratio of the explosive scalar field
Creators: name: Hod, Shahar
Publisher: name: arXiv
Year: 2016
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The well-known superradiant amplification mechanism allows a charged scalar field of proper mass $μ$ and electric charge $q$ to extract the Coulomb energy of a charged Reissner-Nordström black hole. The rate of energy extraction can grow exponentially in time if the system is placed inside a reflecting cavity which prevents the charged scalar field from escaping to infinity. This composed black-hole-charged-scalar-field-mirror system is known as the {\it charged black-hole bomb}. Previous numerical studies of this composed physical system have shown that, in the linearized regime, the inequality $q/μ>1$ provides a necessary condition for the development of the superradiant instability. In the present paper we use analytical techniques to study the instability properties of the charged black-hole bomb in the regime of linearized scalar fields. In particular, we prove that the lower bound ${{q}\overμ}>\sqrt{{r_{\text{m}/r_--1}\over{r_{\text{m}}/r_+-1}}}$ provides a necessary condition for the development of the superradiant instability in this composed physical system (here $r_{\pm}$ are the horizon radii of the charged Reissner-Nordström black hole and $r_{\text{m}}$ is the radius of the confining mirror). This {\it analytically} derived lower bound on the superradiant instability regime of the composed black-hole-charged-scalar-field-mirror system is shown to agree with direct {\it numerical} computations of the instability spectrum.
description: 9 pages
A Theory of Shape-Shifting Droplets
Creators: name: Haas, Pierre A.
name: Goldstein, Raymond E.
name: Smoukov, Stoyan K.
name: Cholakova, Diana
name: Denkov, Nikolai
Publisher: name: arXiv
Year: 2016
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: Recent studies of cooled oil emulsion droplets uncovered transformations into a host of flattened shapes with straight edges and sharp corners, driven by a partial phase transition of the bulk liquid phase. Here, we explore theoretically the simplest geometric competition between this phase transition and surface tension in planar polygons, and recover the observed sequence of shapes and their statistics in qualitative agreement with experiments. Extending the model to capture some of the three-dimensional structure of the droplets, we analyze the evolution of protrusions sprouting from the vertices of the platelets and the topological transition of a puncturing planar polygon.
description: 5 pages, 5 figures
Dissipative phases across the superconductor-to-insulator transition
Creators: name: Couëdo, François
name: Crauste, Olivier
name: Drillien, Anne-Aëlle
name: Humbert, Vincent
name: Bergé, Laurent
name: Marrache-Kikuchi, Claire. A.
name: Dumoulin, Louis
Publisher: name: arXiv
Year: 2016
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Competing phenomena in low dimensional systems can generate exotic electronic phases, either through symmetry breaking or a non-trivial topology. In two-dimensional (2D) systems, the interplay between superfluidity, disorder and repulsive interactions is especially fruitful in this respect although both the exact nature of the phases and the microscopic processes at play are still open questions. In particular, in 2D, once superconductivity is destroyed by disorder, an insulating ground state is expected to emerge, as a result of a direct superconductor-to-insulator quantum phase transition. In such systems, no metallic state is theoretically expected to survive to the slightest disorder. Here we map out the phase diagram of amorphous NbSi thin films as functions of disorder and film thickness, with two metallic phases in between the superconducting and insulating ones. These two dissipative states, defined by a resistance which extrapolates to a finite value in the zero temperature limit, each bear a specific dependence on disorder. We argue that they originate from an inhomogeneous destruction of superconductivity, even if the system is morphologically homogeneous. Our results suggest that superconducting fluctuations can favor metallic states that would not otherwise exist.
Known Pulsars Identified in the GMRT 150 MHz All-Sky Survey
Creators: name: Frail, D. A.
name: Jagannathan, P.
name: Mooley, K. P.
name: Intema, H. T.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We have used the 150 MHz radio continuum survey (TGSS ADR) from the Giant Metrewave Radio Telescope (GMRT) to search for phase-averaged emission toward all well-localized radio pulsars north of -53deg Declination. We detect emission toward 200 pulsars with high confidence (>=5-sigma) and another 88 pulsars at fainter levels. We show that most of our identifications are likely from pulsars, except for a small number where the measured flux density is confused by an associated supernova or pulsar-wind nebula, or a globular cluster. We investigate the radio properties of the 150 MHz sample and we find an unusually high number of gamma-ray binary millisecond pulsars with very steep spectral indices. We also note a discrepancy in the measured flux densities between GMRT and LOFAR pulsar samples, suggesting that the flux density scale for the LOFAR pulsar sample may be in error by approximately a factor two. We carry out a separate search of 30 well-localized gamma-ray, radio-quiet pulsars in an effort to detect a widening of the radio beam into the line-of-sight at lower frequencies. No steep spectrum emission was detected either toward individual pulsars or in a weighted stack of all 30 images.
description: ApJ, in press
Tip induced unconventional superconductivity on Weyl semimetal TaAs
Creators: name: Wang, He
name: Wang, Huichao
name: Chen, Yuqin
name: Luo, Jiawei
name: Yuan, Zhujun
name: Liu, Jun
name: Wang, Yong
name: Jia, Shuang
name: Liu, Xiong-Jun
name: Wei, Jian
name: Wang, Jian
Publisher: name: arXiv
Year: 2016
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Weyl fermion is a massless Dirac fermion with definite chirality, which has been long pursued since 1929. Though it has not been observed as a fundamental particle in nature, Weyl fermion can be realized as low-energy excitation around Weyl point in Weyl semimetal, which possesses Weyl fermion cones in the bulk and nontrivial Fermi arc states on the surface. As a firstly discovered Weyl semimetal, TaAs crystal possesses 12 pairs of Weyl points in the momentum space, which are topologically protected against small perturbations. Here, we report for the first time the tip induced superconductivity on TaAs crystal by point contact spectroscopy. A conductance plateau and sharp double dips are observed in the point contact spectra, indicating p-wave like unconventional superconductivity. Furthermore, the zero bias conductance peak in low temperature regime is detected, suggesting potentially the existence of Majorana zero modes. The experimentally observed tunneling spectra can be interpreted with a novel mirror-symmetry protected topological superconductor induced in TaAs, which can exhibit zero bias and double finite bias peaks, and double conductance dips in the measurements. Our work can open a broad avenue in search for new topological superconducting phases from topological Weyl materials and trigger intensive investigations for pursuing Majorana fermions.
Experimental Quantum Multiparty Communication Protocols
Creators: name: Smania, Massimiliano
name: Elhassan, Ashraf M.
name: Tavakoli, Armin
name: Bourennane, Mohamed
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Quantum information science breaks limitations of conventional information transfer, cryptography and computation by using quantum superpositions or entanglement as resources for information processing. Here, we report on the experimental realization of three-party quantum communication protocols using single three-level quantum system (qutrit) communication: secret sharing, detectable Byzantine agreement, and communication complexity reduction for a three-valued function. We have implemented these three schemes using the same optical fiber interferometric setup. Our realization is easily scalable without sacrificing detection efficiency or generating extremely complex many-particle entangled states.
Speckle suppression and companion detection using coherent differential imaging
Creators: name: Bottom, Michael
name: Wallace, J. Kent
name: Bartos, Randall D.
name: Shelton, J. Chris
name: Serabyn, Eugene
Publisher: name: arXiv
Year: 2016
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Residual speckles due to aberrations arising from optical errors after the split between the wavefront sensor and the science camera path are the most significant barriers to imaging extrasolar planets. While speckles can be suppressed using the science camera in conjunction with the deformable mirror, this requires knowledge of the phase of the electric field in the focal plane. We describe a method which combines a coronagraph with a simple phase-shifting interferometer to measure and correct speckles in the full focal plane. We demonstrate its initial use on the Stellar Double Coronagraph at the Palomar Observatory. We also describe how the same hardware can be used to distinguish speckles from true companions by measuring the coherence of the optical field in the focal plane. We present results observing the brown dwarf HD 49197b with this technique, demonstrating the ability to detect the presence of a companion even when it is buried in the speckle noise, without the use of any standard "calibration" techniques. We believe this is the first detection of a substellar companion using the coherence properties of light.
description: 32 pages, 11 figures. Accepted for publication in MNRAS
Rolling axions during inflation: perturbativity and signatures
Creators: name: Peloso, Marco
name: Sorbo, Lorenzo
name: Unal, Caner
Publisher: name: arXiv
Year: 2016
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The motion of a pseudo-scalar field $X$ during inflation naturally induces a significant amplification of the gauge fields to which it is coupled. The amplified gauge fields can source characteristic scalar and tensor primordial perturbations. Several phenomenological implications have been discussed in the cases in which (i) $X$ is the inflation, and (ii) $X$ is a field different from the inflation, that experiences a temporary speed up during inflation. In this second case, visible sourced gravitational waves (GW) can be produced at the CMB scales without affecting the scalar perturbations, even if the scale of inflation is several orders of magnitude below what is required to produce a visible vacuum GW signal. Perturbativity considerations can be used to limit the regime in which these results are under perturbative control. We revised limits recently claimed for the case (i), and we extend these considerations to the case (ii). We show that, in both cases, these limits are satisfied by the applications that generate signals at CMB scales. Applications that generate gravitational waves and primordial black holes at much smaller scales are at the limit of the validity of this perturbativity analysis, so we expect those results to be valid up to possibly order one corrections.
description: 37 pages, 9 figures
Policy Implementation and Performance of HIV Prevention Projects
Creators: name: Ndungu, Anthony
name: Kidombo, Harriet
Publisher: name: Kenya Policy Briefs
Year: 2020
Subjects: HIV

description: Despite advancements in adolescent and youth sexual and reproductive health (SRH) programmes, the latest data indicate a persistent high need for services. For example, more than 25% of young women are married by 18, increasing their likelihood of having children at an early age. Nearly 33% of young married women have an unmet need for family planning, meaning they wish to delay childbearing but are not using any method of contraception and are at risk of having an unintended pregnancy. Good health and other physical, moral, and intellectual development outcomes are often mutually reinforcing. For example, healthy children do better in school. Similarly, having more years of schooling provides essential information and skills that are linked to more protective and less risky behaviours. There is also strong evidence that peers and parents are influential in shaping gender norms and attitudes. There is some evidence that schools and teachers also shape norms and attitudes. Evidence of the influence of the media is beginning to emerge. This study focused on understanding and proposing solutions to improved implementation of health promotion projects targeting adolescents in Kenya.
Characterization of Hydrogen-Assisted Degradation of a Vintage and a Modern Pipeline Steel
Creators: name: Cauwels, Margo
name: Depraetere, Robin
name: De Waele, Wim
name: Hertelé, Stijn
name: Depover, Tom
name: Verbeken, Kim
Publisher: name: Zenodo
Year: 2022

description: Hydrogen gas has gathered much interest as an energy carrier for present and future clean energy needs. It will play an important part in the storage and transport of energy produced by renewable sources. One economically justifiable method for the transport of hydrogen gas is the use of existing pipeline networks. However, the uptake of hydrogen in steel structures is known to cause a degradation of mechanical properties, potentially decreasing toughness and inducing cracks. This phenomenon is called hydrogen embrittlement (HE). Since the existing pipeline systems were not designed with high-pressure hydrogen gas transport in mind, its suitability needs to be investigated. In this study, the hydrogen properties of two grades pipeline steel, a ‘vintage’ API 5L X56 and a ‘modern’ API 5L X70 are investigated. The influence of hydrogen on their mechanical behavior is evaluated by tensile tests on uncharged and hydrogen charged specimens. These tests are performed on notched round bar specimens with different notch radii, allowing for a range of positive stress triaxialities to be examined. Hydrogen charging is done electrochemically and two different hydrogen levels are used: both steels are tested at the same hydrogen concentration and for the X70 steel, a higher hydrogen concentration is considered as well. Hydrogen signatures in the form of fisheyes and quasi-cleavage are detected on the fracture surface. The influence of different stress triaxialities on fisheye formation is investigated, as well as the role of inclusions or other microstructural features as initiation points for fisheyes. Based on the notched specimens’ reduction in area, the vintage X56 steel appears slightly less or similarly sensitive to HE compared to the higher strength, modern X70 steel for similar hydrogen levels. In the X70 steel, a higher hydrogen concentration results in a more severe embrittlement as well as more fisheyes on the fracture surface.
Replenish Millions of Kenyan Household’s Granaries Through Forest Restoration
Creators: name: Mutune, Jane
Publisher: name: University of Nairobi
Year: 2020
Subjects: Forestry
Kenya

description: Forest degradation has also triggered the scarcity of resources and resulted in conflicts between government and Community Forest Associations (CFAs). Recent conflicts have been witnessed at the Maasai Mau, Cheregani and Mt. Elgon forests. Further, forest destruction precariously exposes women and girls as they walk long distances to fetch fuelwood. About 82 per cent of households use fuelwood for cooking and 1.2 per cent for lighting (KIHBSP, 2017). However, Kenya is only able to meet about 70 per cent of this demand through sustainable domestic supply. The annual deficit of 12 million cubic meters is met by formal and informal imports plus unsustainable extraction from natural forests (KIHBSP, 2017). The situation can be reversed through forest restoration and meaningful involvement of the CFAs in forest co-management.
Establishing the polyextremophilic red microalga Cyanidioschyzon merolae as a host for synthetic biology and scalable production of valuable biomass
Creators: name: Villegas, Melany
name: De Freitas, Barbara
name: Abualsaud, Fatimah
name: Stark, Martha
name: Rader, Stephen
name: Romero, Gabriel
name: Gonzales, Ricardo
name: Fuentes Grunewald, Claudio
name: Lauersen, Kyle J.
Publisher: name: KAUST Research Repository
Year: 2023

description: The Cyanidiales are a group of unicellular red algae that thrive in thermo-acidic environments (pH 0.05-5.0, up to 60 C) and environments with elevated heavy metal concentrations. Cyanidioschyzon merolae 10D is found in acid hydrothermal systems and it can be cultivated in acidified medium (pH 0.5-3) to high biomass in both lab-scale and outdoor conditions with minimal contamination. This alga may be a powerful candidate for synthetic biology and metabolic engineering for heterologous product generation due to its simple genomic features – a small nuclear genome (16.5 Mb) with few introns (0.5%) and 55% GC content– Moreover, unlike other algae, nuclear transformation and integration of transgenes into chromosomes can occur by homologous recombination. Although molecular tools for the successful transformation of this alga have been recently developed, current methods to generate transformants require weeks to months. Here, we report an optimized transformation and selection protocol for C. merolae 10D, generating single chloramphenicol resistant colonies within 6-8 days. We present an in silico designed and de novo constructed modular plasmid toolkit, its transformation, and benchmark transgene expression by fluorescence imaging, flow cytometry, in-gel fluorescence and Western blotting. The transformation and stable expression of several fluorescent reporters in both linear DNA fragments and circular episomes, as well as the application of metabolic engineering for the production of volatile isoprene in this alga is presented for the first time in this work. Additionally, we demonstrated the use of C. merolae as a system for large-scale cultivation with continuous CO2 injection to produce ~2 g L-1 of valuable biomass in 1000 L tubular photobioreactors in the extreme environment of the mid-Red Sea coast during August 2022. This work aims to show that C. merolae is an emerging algal system for metabolic engineering and synthetic biology mediated sustainable and scalable production of engineered bio-products.
D2.5 Harmonization framework M12.pdf
Creators: name: Hernandez, Ignacio
Publisher: name: Zenodo
Year: 2023

description: This specification applies to the project VALKYRIES: Harmonization and PreStandardization of Equipment, Training and Tactical Coordinated procedures for First Aid Vehicles deployment on European multi-victim Disasters funded under the SU-DRS03-2018- 2019-2020 (IA), subtopic 3 Grant Agreement of the Horizon 2020 (H2020) tendering conditions. The document presents the status of the project in terms of standardisation and harmonisation in month 12
Bending stiff charged polymers: the electrostatic persistence length
Creators: name: Trizac, E.
name: Shen, T.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: Many charged polymers, including nucleic acids, are locally stiff. Their bending rigidity -- quantified by the persistence length --, depends crucially on Coulombic features, such as the ionic strength of the solution which offers a convenient experimental route for tuning the rigidity. While the classic Odijk-Skolnick-Fixman treatment fails for realistic parameter values, we derive a simple analytical formula for the electrostatic persistence length. It is shown to be in remarkable agreement with numerically obtained Poisson-Boltzmann theory results, thereby fully accounting for non-linearities, among which counter-ion condensation effects. Specified to double-stranded DNA, our work reveals that the widely used bare persistence length of 500\,Å is overestimated by some 20%
Revisiting Kenya’s Ban on Plastic Carrier Bags
Creators: name: Geoffrey, Elmah
name: Mutune, Jane
Publisher: name: University of Nairobi
Year: 2020
Subjects: Kenya
Environment
Plastic Waste

description: Plastic waste is one of Nairobi’s and, to a greater extent, Kenya’s most visible environmental problems, with most of the flooding witnessed in cities attributed to plastic waste that clogs drainage systems; key among them are plastic carrier bags. These are lightweight, non-biodegradable materials that take ages to decompose. They reduce the aesthetic value of both the natural and physical environment and have since proven to have negative impacts on marine life, livestock and human beings. It is estimated that in their lifetime, livestock ingests an average of 2.5 kgs of plastics, and this has been attributed to losses in the meat industry. Kenya introduced the ban through Gazette notice No. 2356 in 2017. At the time of introduction, about 1 million plastic bags were consumed annually in supermarkets alone. Nairobi City County generates over 2,400 tonnes of waste daily and has alluded to its inability to manage the waste, which mostly consists of food and plastics. Half the waste goes to the Dandora dumpsite, while the remaining waste is either illegally dumped or left uncollected.
Electronic topological transitions in Nb$_3$X (X = Al, Ga, In, Ge and Sn) under compression investigated by first principles calculations
Creators: name: Reddy, P. V. Sreenivasa
name: Kanchana, V.
name: Vaitheeswaran, G.
name: Modak, P.
name: Verma, Ashok K.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: First principles electronic structure calculations of A-15 type Nb$_3$X (X = Al, Ga, In, Ge and Sn) compounds are performed at ambient and high pressures. Mechanical stability is confirmed in all the compounds both at ambient as well as under compression from the calculated elastic constants. We have observed four holes and two electron Fermi surfaces (FS) for all the compounds studied and FS nesting feature is observed at M and along X - $Γ$ in all the compounds. A continuous change in the FS topology is observed under pressure in all the compounds which is also reflected in the calculated elastic constants and density of states under pressure indicating the Electronic topological transitions (ETT). The ETT observed at around 21.5 GPa, 17.5 GPa in Nb$_3$Al and Nb$_3$Ga are in good agreement with the anomalies observed by the experiments.
description: 19 pages, 17 figures
Role of Financial Capabilities in Harnessing Digital Mobile Payments for Enterprise Success
Creators: name: Muraya, Grace
name: Upadhyaya, Radha
Publisher: name: University of Nairobi
Year: 2020
Subjects: Digital Payments
Micro and Small Enterprises
Kenya

description: In Kenya, Micro and Small Enterprises (MSEs) are key engines for growth, creation of employment, innovation, industrial development and GDP growth. The 2016 Kenya National Bureau of Statistics data indicates that this sector accounted for 45 per cent of the establishments and 85 per cent of employment (KNBS, 2016). Despite their great importance, the sector has experienced many challenges, one of them being the exclusion, in terms of access and use, of formal financial products. Financial capability, the theory in which this study is anchored, proposes that an MSE must have the opportunity to access suitable quality financial products (Storchi and Johnson, 2106). However, it emphasizes that the performance of the MSEs and, in turn, the well-being of the entrepreneur hinges on the financial capabilities of the entrepreneur to embed the use of financial products. We examine two aspects of financial capabilities in this study: financial literacy and financial behaviour.
Nanocapillary adhesion between parallel plates
Creators: name: Cheng, Shengfeng
name: Robbins, Mark O.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: Molecular dynamics simulations are used to study capillary adhesion from a nanometer scale liquid bridge between two parallel flat solid surfaces. The capillary force and the meniscus shape of the bridge are computed as the separation between the solid surfaces is varied. Macroscopic theory predicts the meniscus shape and the contribution of liquid/vapor interfacial tension to the capillary force quite accurately for separations as small as 2 or 3 molecular diameters (1-2nm). However the total capillary force differs in sign and magnitude from macroscopic theory for separations less than about 5nm (8-10 diameters) because of molecular layering that is not included in macroscopic theory. For these small separations, the pressure tensor in the fluid becomes anisotropic. The components in the plane of the surface vary smoothly and are consistent with theory based on the macroscopic surface tension. Capillary adhesion is affected by only the perpendicular component, which has strong oscillations as the molecular layering changes.
description: 9 pages, 6 figures, Langmuir, 2016