cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Design, synthesis, antitubercular and antibacterial activities of pyrrolo[3,2-b]pyridine-3-carboxamide linked 2-methoxypyridine derivatives and in silico docking studies
Creators: name: Srinu Bodige
name: Parameshwar Ravula
name: Gulipalli, Kali Charan
name: Endoori, Srinivas
name: Purna Koteswara Rao Cherukumalli
name: Narendra Sharath Chandra JN
name: Nareshvarma Seelam
Publisher: name: Taylor & Francis
Year: 2019
Subjects: subject: Biochemistry
subject: Microbiology
subject: FOS: Biological sciences
subject: Pharmacology
subject: Biotechnology
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: 69999 Biological Sciences not elsewhere classified
subject: 80699 Information Systems not elsewhere classified
subject: FOS: Computer and information sciences
subject: 110309 Infectious Diseases
subject: FOS: Health sciences

description: A novel series pyrrolo[3,2-b]pyridine-3-carboxamide linked 2-methoxypyridine derivatives have been designed, synthesized and confirmed by FT-IR, 1H NMR, 13C NMR, 19F NMR, MS, and elemental analysis. The synthesized compounds were screened for their antitubercular activity using microplate alamar blue assay method and antibacterial activity. Among the tested compounds, 4- fluorophenyl (8m), 4- chlorophenyl (8n) and 4-methoxyphenyl (8i) showed potent anti-TB activity (3.12 µg/mL) in comparison with reference drug, Pyrazinamide ((3.12 µg/mL). In addition, all compounds were docked into DprE1 (PDB code: 4KW5) to explore their binding interactions at the active site. The compounds exhibited essential key interactions as that of reported DprE1 inhibitors and hence, the synthesized compounds may be considered as molecular scaffolds for antitubercular activity. Compounds, 4-chlorophenyl (8n) and 4-flurophenyl (8m) showed significant antibacterial activity against Escherichia coli and Staphylococcus aureus strains. In silico prediction of toxicities, druglikeness and drug score profiles of the tested compounds are promising.
Star formation triggered by HII regions in our Galaxy: First results for N49 from the Herschel infrared survey of the Galactic plane
Creators: name: Zavagno, A.
name: Anderson, L. D.
name: Russeil, D.
name: Morgan, L.
name: Stringfellow, G. S.
name: Deharveng, L.
name: Rodon, J. A.
name: Robitaille, T. P.
name: Mottram, J. C.
name: Schuller, F.
name: Testi, L.
name: Billot, N.
name: Molinari, S.
name: di Gorgio, A.
name: Kirk, J. M.
name: Brunt, C.
name: Ward-Thompson, D.
name: Traficante, A.
name: Veneziani, M.
name: Faustini, F.
name: Calzoletti, L.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: It has been shown that by means of different physical mechanisms the expansion of HII regions can trigger the formation of new stars of all masses. This process may be important to the formation of massive stars but has never been quantified in the Galaxy. We use Herschel-PACS and -SPIRE images from the Herschel Infrared survey of the Galactic plane, Hi-GAL, to perform this study. We combine the Spitzer-GLIMPSE and -MIPSGAL, radio-continuum and sub-millimeter surveys such as ATLASGAL with Hi-GAL to study Young Stellar Objects (YSOs) observed towards Galactic HII regions. We select a representative HII region, N49, located in the field centered on l=30 degr observed as part of the Hi-GAL Science Demonstration Phase, to demonstrate the importance Hi-GAL will have to this field of research. Hi-GAL PACS and SPIRE images reveal a new population of embedded young stars, coincident with bright ATLASGAL condensations. The Hi-GAL images also allow us, for the first time, to constrain the physical properties of the newly formed stars by means of fits to their spectral energy distribution. Massive young stellar objects are observed at the borders of the N49 region and represent second generation massive stars whose formation has been triggered by the expansion of the ionized region. Hi-GAL enables us to detect a population of young stars at different evolutionary stages, cold condensations only being detected in the SPIRE wavelength range. The far IR coverage of Hi-GAL strongly constrains the physical properties of the YSOs. The large and unbiased spatial coverage of this survey offers us a unique opportunity to lead, for the first time, a global study of star formation triggered by HII regions in our Galaxy.
description: 4 pages, 2 figures, accepted by A&A (Special issue on Herschel first results)
Statics of loose triangular embankment under Nadai's sand hill analogy
Creators: name: Pipatpongsa, Thirapong
name: Heng, Sokbil
name: Iizuka, Atsushi
name: Ohta, Hideki
Publisher: name: arXiv
Year: 2010
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: In structural mechanics, Nadai's sand hill analogy is the interpretation of an ultimate torque applied to a given structural member with a magnitude that is analogously twice the volume of stable sand heap which can be accommodated on a transverse cross-section basis. Nadai's analogy is accompanied by his observation of a loose triangular embankment, based on the fact that gravitating loose earth is stable if inclined just under the angle of repose. However, Nadai's analysis of stress distribution in a planar sand heap was found to be inaccurate because the total pressure obtained from Nadai's solution is greater than the self-weight calculated from the heap geometry. This raises a question about the validity of his observation in relation to the analogy. To confirm his criterion, this article presents and corrects the error found in Nadai's solution by analyzing a radially symmetric stress field for a wedge-shaped sand heap with the purpose of satisfying both force balance and Nadai's closure. The fundamental equation was obtained by letting the friction state vary as a function of angular position and deduce it under the constraint that the principal stress orientation obeys Nadai's closure. The theoretical solution sufficiently agreed with the past experimental measurements.
description: text 29 pages, 16 figures, 1 table
How much does movement and location encoding impact prefrontal cortex activity? An algorithmic decoding approach in freely moving rats
Creators: name: Lindsay, Adrian
Publisher: name: University of British Columbia
Year: 2018

description: Specialized brain structures encode spatial locations and movements, yet there is growing evidence that this information is also represented in the rodent medial prefrontal cortex (mPFC). Disambiguating such information from the encoding of other types of task-relevant information has proven challenging. In order to determine the extent to which movement and location information is relevant to mPFC neurons, tetrodes were used to record neuronal activity while limb positions, poses (i.e. recurring constellations of limb positions), velocity and spatial locations were simultaneously recorded with two cameras every 200ms as rats freely roamed in an experimental enclosure. Regression analyses using Generalized Linear Models revealed that over half of the individual mPFC neurons were significantly responsive to at least one of the factors and many were responsive to more than one. On the other hand, each factor accounted for only a very small portion of the total spike count variance of any given neuron (<20% and typically <1%). Artificial Neural Networks and Random Forests were used to analyze ensemble activity and revealed that ensembles were usually superior to the sum of the best neurons in encoding movements and spatial locations. These results indicate that movement and location information have a small impact on any individual mPFC neuron, yet because these weak signals are so widely distributed across the population, this information is strongly represented at the ensemble level.
Chemical composition, antioxidant and antimicrobial activities of Himalayan Fraxinus micrantha Lingelsh leaf extract
Creators: name: Kumar, Parikshit
name: Sati, S.C.
Publisher: name: Taylor & Francis
Year: 2020
Subjects: subject: Biochemistry
subject: Molecular Biology
subject: Pharmacology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Ecology
subject: FOS: Biological sciences
subject: Immunology
subject: FOS: Clinical medicine
subject: 69999 Biological Sciences not elsewhere classified
subject: Cancer
subject: Inorganic Chemistry
subject: Hematology
subject: Plant Biology
subject: 60506 Virology

description: The present investigation determines the phytochemical analysis, antioxidant and antibacterial potential of methanol extract of Himalayan Fraxinus micrantha (Lingelsh) leaves. Chemical analysis of extract revealed the presence of fifty five compounds. The extract was strongly characterised by tyrosol, esculetin, β-sitosterin, l-(+)-ascorbic acid 2,6-dihexadecanoate, (Z,Z)-6,9-cis-3,4-epoxy nonadecadiene as main components (62.6%). The F. micrantha extract presents IC50, 43.93 µg/ml and 68.90 µg/ml using DPPH and H2O2 scavenging assay, respectively. The antibacterial activity of F. micrantha was evaluated for five microorganisms showed that the extract had a remarkable inhibitory potential with a mean zone diameter of inhibition ranging from 11 to 22 mm. The MIC of the extracts ranged from 7.8 to 250 µg/ml and MBC value range 31.25 to 125 µg/ml. F. micrantha showed significant antibacterial activity against B. subtilis (22 mm, ZOI) with MIC and MBC values 7.8 and 31.25 µg/ml respectively.
A Survey on Wireless Sensor Network Security
Creators: name: Sen, Jaydip
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cryptography and Security (cs.CR)
subject: Networking and Internet Architecture (cs.NI)
subject: FOS: Computer and information sciences

description: Wireless sensor networks (WSNs) have recently attracted a lot of interest in the research community due their wide range of applications. Due to distributed nature of these networks and their deployment in remote areas, these networks are vulnerable to numerous security threats that can adversely affect their proper functioning. This problem is more critical if the network is deployed for some mission-critical applications such as in a tactical battlefield. Random failure of nodes is also very likely in real-life deployment scenarios. Due to resource constraints in the sensor nodes, traditional security mechanisms with large overhead of computation and communication are infeasible in WSNs. Security in sensor networks is, therefore, a particularly challenging task. This paper discusses the current state of the art in security mechanisms for WSNs. Various types of attacks are discussed and their countermeasures presented. A brief discussion on the future direction of research in WSN security is also included.
description: 24 pages, 4 figures, 2 tables
Artificial neural network as a universal model of nonlinear dynamical systems
Creators: name: Kuptsov, Pavel V.
name: Kuptsova, Anna V.
name: Stankevich, Nataliya V.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Neural and Evolutionary Computing (cs.NE)
subject: Adaptation and Self-Organizing Systems (nlin.AO)
subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: We suggest a universal map capable to recover a behavior of a wide range of dynamical systems given by ODEs. The map is built as an artificial neural network whose weights encode a modeled system. We assume that ODEs are known and prepare training datasets using the equations directly without computing numerical time series. Parameter variations are taken into account in the course of training so that the network model captures bifurcation scenarios of the modeled system. Theoretical benefit from this approach is that the universal model admits using common mathematical methods without needing to develop a unique theory for each particular dynamical equations. Form the practical point of view the developed method can be considered as an alternative numerical method for solving dynamical ODEs suitable for running on contemporary neural network specific hardware. We consider the Lorenz system, the Roessler system and also Hindmarch-Rose neuron. For these three examples the network model is created and its dynamics is compared with ordinary numerical solutions. High similarity is observed for visual images of attractors, power spectra, bifurcation diagrams and Lyapunov exponents.
description: 17 pages, 10 figures
A re-interpretation of the concept of mass and of the relativistic mass-energy relation
Creators: name: Fiorentin, Stefano Re
Publisher: name: arXiv
Year: 2011
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: For over a century the definitions of mass and derivations of its relation with energy continue to be elaborated, demonstrating that the concept of mass is still not satisfactorily understood. The aim of this study is to show that, starting from the properties of Minkowski spacetime and from the principle of least action, energy expresses the property of inertia of a body. This implies that inertial mass can only be the object of a definition - the so called mass-energy relation - aimed at measuring energy in different units, more suitable to describe the huge amount of it enclosed in what we call the "rest-energy" of a body. Likewise, the concept of gravitational mass becomes unnecessary, being replaceable by energy, thus making the weak equivalence principle intrinsically verified. In dealing with mass, a new unit of measurement is foretold for it, which relies on the de Broglie frequency of atoms, the value of which can today be measured with an accuracy of a few parts in 10^9.
Free fermions and Schur expansions of multi-Schur functions
Creators: name: Iwao, Shinsuke
Publisher: name: arXiv
Year: 2021
Subjects: subject: Combinatorics (math.CO)
subject: Rings and Algebras (math.RA)
subject: FOS: Mathematics
subject: 05E05, 13M10

description: Multi-Schur functions are symmetric functions that generalize the supersymmetric Schur functions, the flagged Schur functions, and the refined dual Grothendieck functions, which have been intensively studied by Lascoux. In this paper, we give a new free-fermionic presentation of them. The multi-Schur functions are indexed by a partition and two ``tuples of tuples'' of indeterminates. We construct a family of linear bases of the fermionic Fock space that are indexed by such data and prove that they correspond to the multi-Schur functions through the boson-fermion correspondence. By focusing on some special bases, which we call refined bases, we give a straightforward method of expanding a multi-Schur function in the refined dual Grothendieck polynomials. We also present a sufficient condition for a multi-Schur function to have its Hall-dual function in the completed ring of symmetric functions.
description: 18 pages
Convenient synthesis and antitumor evaluation of some new 9-ethyl-3-(hetaryl)carbazoles
Creators: name: Bondock, Samir
name: Alqahtani, Salwa
name: Fouda, Ahmed M.
Publisher: name: Taylor & Francis
Year: 2019
Subjects: subject: Biophysics
subject: Biochemistry
subject: Cell Biology
subject: Pharmacology
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: 69999 Biological Sciences not elsewhere classified
subject: FOS: Biological sciences
subject: Cancer
subject: Plant Biology

description: In continuing our efforts to develop new potent anticancer candidates, a new series of 9-ethylcarbazoles carrying at position 3 various heterocyclic substituents such as 2-imino-2H-chromenes 5a–e, 2-oxo-2H-chromenes 6a–e, 3-imino-3H-benzo[f]chromene 8, 3-oxo-3H-benzo[f]chromene 9, 2-pyridones 11, 14, pyrazole 19, pyrimidine 23, pyrido[1,2-a]pyrimidine 27, 2H-pyran-2-one 30, and pyrano[2,3-d]pyrimidinetrione 34 were efficiently synthesized, characterized and evaluated for their in vitro antitumor activity. The mechanism for the synthesis of compounds was also discussed. Most of the synthesized compounds were displayed the considerable anticancer activities against three human tumor cells lines, in particular, colon carcinoma (HCT-116), hepatocellular carcinoma (HepG-2) and breast cancer (MCF-7). Compound 6d proves as most active molecule in this study with special effectiveness against the human HCT-116 and HepG-2 as its IC50 values are 1.50, 0.90 μM, respectively, when doxorubicin is compared. Compound 34 was also found to have high activity against HepG-2, HCT-116 and moderate activity against MCF-7.
Whitehall Farm: An Innovative silvoarable orchard system in the UK - Whitehallin tila: Agrometsätalouden innovaatioita –hedelmätarha malli
Creators: name: Knight
name: , Ian
Publisher: name: Zenodo
Year: 2019
Subjects: orchard
apple
silvopastoral
intercropping
hedelmätarha
omena
agrometsätalous
puustoviljely
peltometsäviljely
peltokasviviljely

description: Whitehall Farm tilalla Cambridgeshiressa lähellä Peterboroughin kaupunkia vuokraviljelijöinä toimivat
Stephen ja Lynn Briggs ovat modernin agrometsätalouden pioneereja. Whitehallin 100 hehtaarin tila
sijaitsee alavalla turvemaalla ja siellä viljellään orgaanisia vihanneksia ja viljakasveja sekä apilaa.
Tilalla ei ole karjaa.
Tilan 52 hehtaarin viljelysmaille istutettiin 4500 puuta, jotka vievät ainoastaan 4 hehtaaria (8%) maaalasta. Loput 48 hehtaaria jää peltokasviviljelmille puurivien väleihin - At Whitehall Farm near Peterborough, Cambridgeshire tenant farmers Stephen and Lynn Briggs have become modern agroforestry pioneers in silvoarable production. Whitehall Farm is a 100 hectare stockless organic arable farm located on fenland peat soil growing field scale vegetables, cereals alongside fertility building grass clover leys. At Whitehall Farm 4,500 trees were planted across 52 hectares of arable land, with apple trees only occupying 4 ha (8%) leaving 48 ha (92%) for arable cropping between the tree rows.
Quantum Gates and Memory using Microwave Dressed States
Creators: name: Timoney, N.
name: Baumgart, I.
name: Johanning, M.
name: Varon, A. F.
name: Wunderlich, Ch.
name: Plenio, M. B.
name: Retzker, A.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Trapped atomic ions have been successfully used for demonstrating basic elements of universal quantum information processing (QIP). Nevertheless, scaling up of these methods and techniques to achieve large scale universal QIP, or more specialized quantum simulations remains challenging. The use of easily controllable and stable microwave sources instead of complex laser systems on the other hand promises to remove obstacles to scalability. Important remaining drawbacks in this approach are the use of magnetic field sensitive states, which shorten coherence times considerably, and the requirement to create large stable magnetic field gradients. Here, we present theoretically a novel approach based on dressing magnetic field sensitive states with microwave fields which addresses both issues and permits fast quantum logic. We experimentally demonstrate basic building blocks of this scheme to show that these dressed states are long-lived and coherence times are increased by more than two orders of magnitude compared to bare magnetic field sensitive states. This changes decisively the prospect of microwave-driven ion trap QIP and offers a new route to extend coherence times for all systems that suffer from magnetic noise such as neutral atoms, NV-centres, quantum dots, or circuit-QED systems.
description: 9 pages, 4 figures
Detection of quantum phase transition in spin-1 chain through multipartite high-order correlations
Creators: name: Lee, Dongkeun
name: Sohbi, Adel
name: Son, Wonmin
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We design a Bell inequality that is violated by correlations obtained from the ground states of XXZ spin-1 chain with on site anisotropies at the region of phase transition. In order to detect such correlations in spin-1 systems we exploit the formalism of generalized Bell inequality via the use of multipartite and high order correlations. We observe sharp violation in the vicinity of quantum phase transition between the so called large D and AFM phase. Interestingly, the violation of our Bell inequality is manifested by the change of the XXZ spin-1 chain ground state to a Greenberger-Horne-Zeilinger (GHZ)-like state at the critical region. Our results provide the first characterization of quantum phase transition via the violation of Bell-type constraint by correlations in the XXZ spin-1 chain with multi-body correlations and high-order measurements.
description: 8 pages, 12 figures
Harmonizing water footprint assessments for agricultural production in Southern Amazonia
Creators: name: Lathuillière, Michael Jacques
Publisher: name: University of British Columbia
Year: 2018

description: Since its inception in 2002, the water footprint (WF) has brought new insight into the direct and indirect (or supply chain) uses of water in the production and consumption of goods and services. Today, this emerging field is mainly represented by two distinct communities following distinct WF approaches: the water resources management community which follows guidelines from the WF Network, and the life cycle assessment (LCA) community which focuses on assessing impacts from water use. This thesis seeks to harmonize WF assessments by combining and contrasting methods and objectives from both communities with the overarching goal of informing water decision-making by (1) considering limits to water resources within a river basin (the “Nature” domain), and (2) considering water use in production systems (the “Production” domain). Following this proposed framework to combine WF assessments (Chapter 2), I assess how each approach may address water management for agricultural production in Southern Amazonia (Mato Grosso, Brazil), a region that has dramatically increased its soybean and cattle production through deforestation. In Chapters 3 and 4, I respectively measure and model the WF of cropland and cattle to highlight on-farm water use strategies for agricultural production (the volumetric WF assessment phase). Chapter 5 focuses on the Xingu Basin of Mato Grosso for which I assess water scarcity of current and future agricultural production (the volumetric WF sustainability assessment phase). Finally, in Chapter 6, I integrate existing water use in LCA methods to highlight water use efficiencies through impact assessment (the WF impact assessment phase). Results show different land and water management options for crops and cattle in Southern Amazonia, but also demonstrate that water use for future production could reach sustainable limits, should cropland irrigation and cattle confinement become more widespread. Moreover, the role of water vapour supply to the atmosphere through evapotranspiration is stressed as an important process that could affect future water availability due to the importance of moisture recycling on regional precipitation. This research provides context on the role of land management on water resources, while combining water decisions affecting both production systems and resource limits imposed by the water cycle.
A study of the distant activity of comet C/2006 W3 (Christensen) using Herschel and ground-based radio telescopes
Creators: name: Bockelée-Morvan, D.
name: Hartogh, P.
name: Crovisier, J.
name: Vandenbussche, B.
name: Swinyard, B. M.
name: Biver, N.
name: Lis, D. C.
name: Jarchow, C.
name: Moreno, R.
name: Hutsemékers, D.
name: Jehin, E.
name: Küppers, M. K.
name: Lara, L. M.
name: Lellouch, E.
name: Manfroid, J.
name: de Val-Borro, M.
name: Szutowicz, S.
name: Banaszkiewicz, M.
name: Bensch, F.
name: Blecka, M. I.
name: Emprechtinger, M.
name: Encrenaz, T.
name: Fulton, T.
name: Kidger, M.
name: Rengel, M.
name: Waelkens, C.
name: Bergin, E.
name: Blake, G. A.
name: Blommaert, J. A. D. L.
name: Cernicharo, J.
name: Decin, L.
name: Encrenaz, P.
name: de Graauw, T.
name: Leeks, S.
name: Medvedev, A. S.
name: Naylor, D.
name: Schieder, R.
name: Thomas, N.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Comet C/2006 W3 (Christensen) was observed in November 2009 at 3.3 AU from the Sun with Herschel. The PACS instrument acquired images of the dust coma in 70- and 160-micrometers filters, and spectra covering several H2O rotational lines. Spectra in the range 450-1550 GHz were acquired with SPIRE. The comet emission continuum from 70 to 672 micrometers was measured, but no lines were detected. The spectral energy distribution indicates thermal emission from large particles and provides a measure of the size distribution index and dust production rate. The upper limit to the water production rate is compared to the production rates of other species (CO, CH3OH, HCN, H2S, OH) measured with the IRAM 30-m and Nancay telescopes. The coma is found to be strongly enriched in species more volatile than water, in comparison to comets observed closer to the Sun. The CO to H2O production rate ratio exceeds 220%. The dust to gas production rate ratio is on the order of 1.
description: Accepted for publication in Astronomy & Astrophysics (special issue on Herschel first results)
A new xanthone and a biphenyl from the flower and twig extracts of Garcinia mckeaniana
Creators: name: Auranwiwat, Chiramet
name: Limtharakul, Thunwadee
name: Pyne, Stephen G.
name: Rattanajak, Roonglawan
name: Kamchonwongpaisan, Sumalee
Publisher: name: Taylor & Francis
Year: 2019
Subjects: subject: Biochemistry
subject: 29999 Physical Sciences not elsewhere classified
subject: FOS: Physical sciences
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Ecology
subject: FOS: Biological sciences
subject: 69999 Biological Sciences not elsewhere classified

description: The phytochemical investigation of the flower and twig extracts of Garcinia mckeaniana yielded a new xanthone, mckeanianone F (1) and a new biphenyl, mckeaniabiphenyl (2) together with 15 known compounds. The isolated compounds were characterized using spectroscopic techniques and mass spectrometry. Some of the isolated compounds from the twigs exhibited antimalarial and cytotoxic activities.
Redundant representations help generalization in wide neural networks
Creators: name: Doimo, Diego
name: Glielmo, Aldo
name: Goldt, Sebastian
name: Laio, Alessandro
Publisher: name: arXiv
Year: 2021
Subjects: subject: Machine Learning (stat.ML)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Deep neural networks (DNNs) defy the classical bias-variance trade-off: adding parameters to a DNN that interpolates its training data will typically improve its generalization performance. Explaining the mechanism behind this ``benign overfitting'' in deep networks remains an outstanding challenge. Here, we study the last hidden layer representations of various state-of-the-art convolutional neural networks and find that if the last hidden representation is wide enough, its neurons tend to split into groups that carry identical information, and differ from each other only by statistically independent noise. The number of such groups increases linearly with the width of the layer, but only if the width is above a critical value. We show that redundant neurons appear only when the training process reaches interpolation and the training error is zero.
29-Norlupane-1β-hydroxy-3,20-dione, a new norlupane triterpenoid from the twigs and leaves of Phyllanthus acidus
Creators: name: Sichaem, Jirapast
name: Vo, Huu-Canh
name: Nha-Tran, Thanh
name: Jarupinthusophon, Suekanya
name: Niamnont, Nakorn
name: Srikittiwanna, Kittiwat
name: Nguyen, Thu-Khuyen
name: Tran, Thi-Ngoc-Mai
name: Le, Tran-Thai-Duong
name: Duong, Thuc-Huy
Publisher: name: Taylor & Francis
Year: 2019
Subjects: subject: Biochemistry
subject: Medicine
subject: Genetics
subject: FOS: Biological sciences
subject: Molecular Biology
subject: Pharmacology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Ecology
subject: Sociology
subject: FOS: Sociology
subject: 69999 Biological Sciences not elsewhere classified
subject: Plant Biology

description: A new norlupane triterpenoid, 29-norlupane-1β-hydroxy-3,20-dione (1), along with ten known compounds, 29-norlup-1-ene-3,20-dione (2), phyllanthol (3), phyllanthone (4), glochidone (5), lupeol (6), lupeone (7), 4-hydroxybenzoic acid (8), 4-hydroxybenzaldehyde (9), phyllane A (10) and methyl β-orsellinate (11) were isolated the twigs and leaves of Phyllanthus acidus. The structure of 1 was identified by interpretation of their spectroscopic data and comparison with those reported in the literature. In addition, all isolated compounds 1–11 were evaluated for their antioxidant activity.
Universal noise-precision relations in variational quantum algorithms
Creators: name: Ito, Kosuke
name: Mizukami, Wataru
name: Fujii, Keisuke
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Variational quantum algorithms (VQAs) are expected to become a practical application of near-term noisy quantum computers. Although the effect of the noise crucially determines whether a VQA works or not, the heuristic nature of VQAs makes it difficult to establish analytic theories. Analytic estimations of the impact of the noise are urgent for searching for quantum advantages, as numerical simulations of noisy quantum computers on classical computers are heavy and quite limited to small scale problems. In this paper, we establish analytic estimations of the error in the cost function of VQAs due to the noise. The estimations are applicable to any typical VQAs under the Gaussian noise, which is equivalent to a class of stochastic noise models. Notably, the depolarizing noise is included in this model. As a result, we obtain estimations of the noise level to guarantee a required precision. Our formulae show how the Hessian of the cost function, the spectrum of the target operator, and the geometry of the ansatz affect the sensitivity to the noise. This insight implies trade-off relations between the trainability and the noise resilience of the cost function. We also obtain rough estimations which can be easily calculated without detailed information of the cost function. As a highlight of the applications of the formula, we propose a quantum error mitigation method which is different from the extrapolation and the probabilistic error cancellation.
description: 20 pages, 4 figures, published version
Closed timelike curves and causality violation
Creators: name: Lobo, Francisco S. N.
Publisher: name: arXiv
Year: 2010
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 conceptual definition and understanding of time, both quantitatively and qualitatively is of the utmost difficulty and importance. As time is incorporated into the proper structure of the fabric of spacetime, it is interesting to note that General Relativity is contaminated with non-trivial geometries which generate closed timelike curves. A closed timelike curve (CTC) allows time travel, in the sense that an observer that travels on a trajectory in spacetime along this curve, may return to an event before his departure. This fact apparently violates causality, therefore time travel and it's associated paradoxes have to be treated with great caution. The paradoxes fall into two broad groups, namely the consistency paradoxes and the causal loops. A great variety of solutions to the Einstein field equations containing CTCs exist and it seems that two particularly notorious features stand out. Solutions with a tipping over of the light cones due to a rotation about a cylindrically symmetric axis and solutions that violate the energy conditions. All these aspects are analyzed in this review paper.
description: 19 pages, 6 figures. Invited chapter to appear in an edited collection 'Classical and Quantum Gravity: Theory, Analysis and Applications'
SelfCF: A Simple Framework for Self-supervised Collaborative Filtering
Creators: name: Zhou, Xin
name: Sun, Aixin
name: Liu, Yong
name: Zhang, Jie
name: Miao, Chunyan
Publisher: name: arXiv
Year: 2021
Subjects: subject: Information Retrieval (cs.IR)
subject: Artificial Intelligence (cs.AI)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Collaborative filtering (CF) is widely used to learn informative latent representations of users and items from observed interactions. Existing CF-based methods commonly adopt negative sampling to discriminate different items. Training with negative sampling on large datasets is computationally expensive. Further, negative items should be carefully sampled under the defined distribution, in order to avoid selecting an observed positive item in the training dataset. Unavoidably, some negative items sampled from the training dataset could be positive in the test set. In this paper, we propose a self-supervised collaborative filtering framework (SelfCF), that is specially designed for recommender scenario with implicit feedback. The proposed SelfCF framework simplifies the Siamese networks and can be easily applied to existing deep-learning based CF models, which we refer to as backbone networks. The main idea of SelfCF is to augment the output embeddings generated by backbone networks, because it is infeasible to augment raw input of user/item ids. We propose and study three output perturbation techniques that can be applied to different types of backbone networks including both traditional CF models and graph-based models. The framework enables learning informative representations of users and items without negative samples, and is agnostic to the encapsulated backbones. We conduct comprehensive experiments on four datasets to show that our framework may achieve even better recommendation accuracy than the encapsulated supervised counterpart with a 2$\times$--4$\times$ faster training speed. We also show that SelfCF can boost up the accuracy by up to 17.79% on average, compared with a self-supervised framework BUIR.
description: Accepted to ACM Transactions on Recommender Systems (TORS). Code: https://github.com/enoche/SelfCF
Agonistic behaviour and electric signalling in a mormyrid fish, Gnathonemus petersii
Creators: name: Kramer, Bernd
name: Bauer, Richard
Publisher: name: Universität Regensburg
Year: 1976
Subjects: subject: 590 Tiere (Zoologie)

description: 1. Agonistic motor behaviour and concurrent electric signalling were studied in individually held, residential Gnathonemus petersii. Aggressive behaviour was elicited by presenting a specimen of a closely related species, Mormyrus rume, for 3 min a day. 2. The principal agonistic motor patterns are described (Fig. 2). Among them head butt, approach and lateral display were further analysed. 3. The electrical activity displayed during agonistic behaviour was found to differ fundamentally both from isolated resting and swimming conditions. The mean discharge rate recorded during aggressive behaviour (31 Hz, Fig. 3 c) is approximately twice the rate observed in an isolated swimming fish (Fig. 3b) and three times the rate displayed by a resting animal (Fig. 3a). An attacking G. petersii exhibits a much greater range of electric organ discharge (EOD) intervals than isolated swimming or resting individuals. EOD-interval histograms recorded from attacking fish show two sharp modes at high discharge rate; there are no intermediate intervals. 4. During the course of an attack, the initially low and variable discharge rate increases fairly linearly as the distance from the attacked fish diminishes (Fig. 9). The EOD rate associated with physical contact (head butt) comprises between 60 and 80 Hz in 24 of 28 attacks analysed; the dominant mode of the distribution is 61 Hz (Fig. 8). 5. During subsequent lateral display, G. petersii emits a high discharge rate pattern consisting of two types of ldquosteady-staterdquo activities which may last up to a few seconds: the first is a fairly regular alternation of approx. 16 and 8 ms intervals (paired pulses); this pattern gives rise to the two peaks of high discharge rate in the interval histogram (Fig. 3c). The second is a regular sequence of either 16 or 8 ms intervals (Fig. 4A). The only female among the animals used in our study showed the same display but did not exhibit the highest possible discharge rate (i.e. a regular sequence or 8 ms intervals; Fig. 4B). The high discharge rate is terminated by a sudden discharge break (Figs. 4A and 6). 6. It is suggested that the attack-associated EOD rate increase is a remnant of an ordinary locomotory pattern which has changed its function to a ritualised aggressive signal that occurs in a socially significant and well-defined context. The high discharge rate might serve three functions: (i) behavioural isolation of closely related, sympatrically living mormyrids (perhaps by character displacement); (ii) recognition of sexes; (iii)_synchronisation of mates during courtship.
The Elemental Abundance Distributions of Milky Way Satellite Galaxies
Creators: name: Kirby, Evan N.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The chemical compositions of the stars in Milky Way (MW) satellite galaxies reveals the history of gas flows and star formation (SF) intensity. This talk presented a Keck/DEIMOS spectroscopic survey of the Fe, Mg, Si, Ca, and Ti abundances of nearly 3000 red giants in eight MW dwarf satellites. The metallicity and alpha-to-iron ratio distributions obey the following trends: (1) The more luminous galaxies are more metal-rich, indicating that they retained gas more efficiently than the less luminous galaxies. (2) The shapes of the metallicity distributions of the more luminous galaxies require gas infall during their SF lifetimes. (3) At [Fe/H] < -1.5, [alpha/Fe] falls monotonically with increasing [Fe/H] in all MW satellites. One interpretation of these trends is that the SF timescale in any MW satellite is long enough that Type Ia supernovae exploded for nearly the entire SF lifetime.
description: 6 pages, 4 figures, proceeding of oral contribution to A Universe of Dwarf Galaxies, Lyon, France, July 2010
Electrically tunable room-temperature ferromagnetism in CrBr$_3$
Creators: name: Singh, Chandan K.
name: Kabir, Mukul
Publisher: name: arXiv
Year: 2021
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The recent discovery of magnetic ordering in two-dimension has lead to colossal efforts to find atomically thin materials that order at high temperatures. However, due to fundamental spin fluctuation in reduced dimension, the room-temperature ferromagnetism remains elusive. Here, we report a dramatic manipulation of magnetic ordering up to room temperature in the monolayer CrBr$_3$, within the first-principles Heisenberg XXZ model. The exchange and anisotropic magnetic interactions are externally modulated by a gate-induced charge carrier doping that triggers a nontrivial phase diagram. High-temperature ferromagnetism is associated with a substantial increase in both effective ferromagnetic exchange and overall magnetic anisotropy under experimentally attainable hole doping. In contrast, electron doping quickly switches the magnetic easy axis. The gate-tuneable room temperature ferromagnetism in CrBr$_3$ presents new possibilities in electrically controlled spintronic and magnetoelectric devices based on atomically thin crystals.
description: 6 pages, 3 figures, supplementary information
Chemical constituents from Schisandra sphenanthera and their cytotoxic activity
Creators: name: Thi, Nguyen
name: Van Doan, Vu
name: Lan, Hoang Thi Tuyet
name: Anh, Bui Thi Mai
name: Hoang, Nguyen Huy
name: Tai, Bui Huu
name: Nhiem, Nguyen Xuan
name: Yen, Pham Hai
name: Park, Seon Ju
name: Seo, Yohan
name: Namkung, Wan
name: Kim, Seung Hyun
name: Van Kiem, Phan
Publisher: name: Taylor & Francis
Year: 2022
Subjects: subject: Biochemistry
subject: Space Science
subject: Pharmacology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Ecology
subject: FOS: Biological sciences
subject: Sociology
subject: FOS: Sociology
subject: 69999 Biological Sciences not elsewhere classified

description: Extensive phytochemical investigation of Schisandra sphenanthera leaves resulted in the isolation of six highly oxygenated nortriterpenoids (1–6) and five lignans (7–11) including a new pre-schisanartane-type, schisandrathera A (1), a new dibenzocyclooctadiene glycoside, schisandrathera B (7) and two new lignans, schisandrathera C (8) and schisandrathera D (9). Their chemical structures including absolute configurations were determined extensively by means of HR-ESI-MS, NMR, and ECD spectra. In addition, all isolated compounds were tested for cytotoxic activity against PC3 (prostate cancer) and MCF7 (breast cancer) cell lines. Among these compounds, schirubrisin B (3) showed strong cytotoxic effect on both PC3 and MCF7 cell lines with IC50 values of 3.21 ± 0.68, 13.30 ± 0.68 μM, respectively, whereas ten remaining compounds were found to be less effective in the investigated models.
A new indole alkaloid and other constituents from Monodora minor and Uvaria tanzaniae: their antitrypanosomal and antiplasmodial evaluation
Creators: name: Christopher, Robert
name: Mgani, Quintino A.
name: Nyandoro, Stephen S.
name: Rousseau, Amanda L.
name: Isaacs, Michelle
name: Hoppe, Heinrich C.
Publisher: name: Taylor & Francis
Year: 2020
Subjects: subject: Biochemistry
subject: 29999 Physical Sciences not elsewhere classified
subject: FOS: Physical sciences
subject: Medicine
subject: Microbiology
subject: FOS: Biological sciences
subject: Pharmacology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Plant Biology

description: Phytochemical investigation of the methanolic extract of Monodora minor Engl. & Diels (Annonaceae) stem bark yielded a new indole (E)-4-(1H-indol-5-yl)-but-3-en-2-one (1), a known indole 5-formyl-1H-indole (2) and an ubiquitous steroid sitosterol (3). The investigations of the methanolic extract of Uvaria tanzaniae Verdc. (Annonaceae) root bark yielded two previously reported C-benzylated dihydrochalcones namely uvaretin (4) and diuvaretin (5). Structures of the isolated compounds were elucidated based on NMR spectroscopy and high resolution electron ionization mass spectrometry (HR-EI-MS) data. All compounds were tested against Trypanosoma brucei brucei and Plasmodium falciparum. At a single concentration (20 μM) in the antitrypanosomal and antiplasmodial assays, compound 4 exhibited remarkable activities against T. brucei brucei and P. falciparum with percentage inhibition of 97.3% and 83.0% respectively, whereas compounds 1, 2, 3 and 5 were inactive. In a dose response antiplasmodial assay compound 4 exhibited moderate activity against P. falciparum with an IC50 value of 7.20 μM.
Beyond the Freshman's Dream: Classical fractal spin liquids from matrix cellular automata in three-dimensional lattice models
Creators: name: Biswas, Sounak
name: Kwan, Yves H.
name: Parameswaran, S. A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We construct models hosting classical fractal spin liquids on two realistic three-dimensional (3D) lattices of corner-sharing triangles: trillium and hyperhyperkagome (HHK). Both models involve the same form of three-spin Ising interactions on triangular plaquettes as the Newman-Moore (NM) model on the 2D triangular lattice. However, in contrast to the NM model and its 3D generalizations, their degenerate ground states and low-lying excitations cannot be described in terms of scalar cellular automata (CA), because the corresponding fractal structures lack a simplifying algebraic property, often termed the 'Freshman's dream'. By identifying a link to matrix CAs -- that makes essential use of the crystallographic structure -- we show that both models exhibit fractal symmetries of a distinct class to the NM-type models. We devise a procedure to explicitly construct low-energy excitations consisting of finite sets of immobile defects or "fractons", by flipping arbitrarily large self-similar subsets of spins, whose fractal dimensions we compute analytically. We show that these excitations are associated with energetic barriers which increase logarithmically with system size, leading to "fragile" glassy dynamics, whose existence we confirm via classical Monte Carlo simulations. We also discuss consequences for spontaneous fractal symmetry breaking when quantum fluctuations are introduced by a transverse magnetic field, and propose multi-spin correlation function diagnostics for such transitions. Our findings suggest that matrix CAs may provide a fruitful route to identifying fractal symmetries and fracton-like behaviour in lattice models, with possible implications for the study of fracton topological order.
description: 24 pages, 14 figures
Chromium(VI) oxide-mediated oxidation of polyalkyl-polypyridines to polypyridine-polycarboxylic acids with periodic acid
Creators: name: Yamazaki, Shigekazu
Publisher: name: Taylor & Francis
Year: 2019
Subjects: subject: Biochemistry
subject: Medicine
subject: Microbiology
subject: FOS: Biological sciences
subject: Cell Biology
subject: Genetics
subject: Molecular Biology
subject: Neuroscience
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: Ecology
subject: Inorganic Chemistry
subject: Plant Biology
subject: Computational Biology

description: 4,4′-Dicarboxy-2,2′-bipyridine was synthesized quantitatively by chromium(VI) oxide-mediated oxidation of 4,4′-dimethyl-2,2′-bipyridine or 4,4′-diethyl-2,2′-bipyridine with periodic acid as the terminal oxidant in sulfuric acid. 5,5′-Dicarboxy-2,2′-bipyridine and 6,6’-dicarboxy-2,2′-bipyridine were also synthesized by the method from the corresponding dimethyl bipyridines in excellent yields. 4,4′,4″-Tricarboxy-2,2′:6′,2″-terpyridine was obtained in 80% yield from 4,4′,4″-triethyl-2,2′:6′,2″-terpyridine, and 4,4′,4″,4′″-tetracarboxy-2,2′:6′,2″:6″,2′″-quaterpyridine was obtained in 72% yield from 4,4′,4″,4′″-tetraethyl-2,2′:6′,2″:6″,2′″-quaterpyridine by the same procedure.