cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Positive Neural Networks in Discrete Time Implement Monotone-Regular Behaviors
Creators: name: Ameloot, Tom J.
name: Bussche, Jan Van den
Publisher: name: arXiv
Year: 2015
Subjects: subject: Neural and Evolutionary Computing (cs.NE)
subject: FOS: Computer and information sciences

description: We study the expressive power of positive neural networks. The model uses positive connection weights and multiple input neurons. Different behaviors can be expressed by varying the connection weights. We show that in discrete time, and in absence of noise, the class of positive neural networks captures the so-called monotone-regular behaviors, that are based on regular languages. A finer picture emerges if one takes into account the delay by which a monotone-regular behavior is implemented. Each monotone-regular behavior can be implemented by a positive neural network with a delay of one time unit. Some monotone-regular behaviors can be implemented with zero delay. And, interestingly, some simple monotone-regular behaviors can not be implemented with zero delay.
The influence of the parent metal condition on the cross-weld creep performance in Grade 91 steel
Creators: name: Siefert, John
Publisher: name: Figshare
Year: 2019
Subjects: subject: 91299 Materials Engineering not elsewhere classified
subject: FOS: Materials engineering

description: There are thousands of technical papers, reports and other documents which seek to identify the key factors affecting the performance of Grade 91 steel. Yet, as evidenced by the recent reduction in stress allowable values for Grade 91 steel and the introduction of a Type II specification in the ASME B&PV Code, considerable uncertainty still exists regarding the performance, composition and heat treatment.Knowledge regarding the creep performance of weldments is even more limited and opinions on damage development even more diverse. This point is pertinent whether consideration is given to laboratory cross-weld creep behavior or whether the assessment considers thick section components operating under high pressure and temperature. In part, this additional complexity is because the welding thermal cycle introduces a heat affected zone (HAZ). Although it is widely recognized that the HAZ is linked to creep failures of welds which is likely to be life-limiting in structures, there is no agreement over basic approaches such as the correct methods to characterize the microstructures formed, how to classify the structures and the specifics of the region where creep failure occurs. For example, published work states that the locations for failure should be described as the soft-zone, the subcritical heat affected zone (SCHAZ), the over tempered zone (OTZ), the intercritical heat affected zone (ICHAZ) or the fine-grained heat affected zone (FGHAZ). It is thus apparent that for cross-weld behavior in Grade 91 steel these descriptions cannot be simultaneously and technically accurate. [Continues.]
Investigation of the dealloying front in partially corroded alloys
Creators: name: Mahr, Christoph
name: Burgos, Jorge Adrian Tapia
name: Schowalter, Marco
name: Wittstock, Arne
name: Rosenauer, Andreas
Publisher: name: Taylor & Francis
Year: 2022
Subjects: subject: Biochemistry
subject: Space Science
subject: Medicine
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: 69999 Biological Sciences not elsewhere classified
subject: FOS: Biological sciences
subject: Computational Biology

description: Nanoporous gold as obtained by corrosion of alloys of gold and a less noble metal is a system with manifold applications. The process of dealloying, however, can result in partially porous samples, when dealloying conditions are not optimized with respect to composition and pre-treatment of the master alloy. In the present work, we investigate the dealloying interface between porous material and non-porous alloy in two samples, in which dealloying either stopped automatically or was interrupted manually. Reasons for unintended termination of dealloying in the former case are suggested.
Characterization of multiplier ideal sheaves with weights of Lelong number one
Creators: name: Guan, Qi'an
name: Zhou, Xiangyu
Publisher: name: arXiv
Year: 2014
Subjects: subject: Complex Variables (math.CV)
subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics

description: In this article, we characterize plurisubharmonic functions of Lelong number one at the origin, such that the germ of the associated multiplier ideal sheaf is nontrivial: in arbitrary complex dimension, their singularity must be the sum of a germ of smooth divisor and of a plurisubharmonic function with zero Lelong number. We also present a new proof of the related well known integrability criterion due to Skoda.
description: 14 pages, 0 figures. Revised version
Essays on firms in the global economy
Creators: name: Gravino, Daniel
Publisher: name: Figshare
Year: 2019
Subjects: subject: 150399 Business and Management not elsewhere classified
subject: FOS: Economics and business

description: This thesis explores how taxes and subsidies can influence the decisions of strategic firms acting in the global economy. Chapter 1 considers tax/subsidy competition for a multinational enterprise (MNE) between the governments of two potential host countries. It is shown that the MNE's decision to locate in the proximity of firms producing a homogeneous product may be the result of government subsidies that aim to capitalise on the potential for knowledge spillovers to indigenous industry; and that fiscal competition to host the MNE may increase the welfare of both winning and losing countries when it leads to the relocation of multinationals away from countries that do not have the potential to benefit from knowledge spillovers to countries that do. Chapter 2 analyses the impact of anti-profit-shifting policies in a model with competition for an MNE's production plant and its profits between two governments that have at their disposal two fiscal policy instruments. It is shown that any gains in tax revenues resulting from more costly profit shifting may be partly offset by higher subsidies in the bidding stage for the MNE's plant such that the positive impact of anti-tax avoidance policies on host countries' tax revenues may be smaller than anticipated. [Continues.]
Optimization of extraction and dyeing conditions of the Parkia roxburghii pod’s peel as a natural substantive silk dye
Creators: name: Shantibala, T.
name: Ansari, Mohd Talha
name: Tatan, Tantulung
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Biophysics
subject: Biochemistry
subject: Medicine
subject: Cell Biology
subject: Biotechnology
subject: Evolutionary Biology
subject: FOS: Biological sciences
subject: Environmental Sciences not elsewhere classified
subject: Ecology
subject: Infectious Diseases
subject: FOS: Health sciences
subject: Plant Biology

description: Natural dyes are soft, eco-friendly, and non-toxic colours for silk fabric, imparting high compatibility with the environment. Among the different natural dyestuffs derived from different parts of plants, the peel of the Parkia roxburghii pod is thriving as one of the potential natural substantive dyes. The study reveals optimization of dye extraction for dyeing silk fabric. Colour strength (K/S) and absorbance of dye extract were evaluated for optimization of extraction and dyeing parameters. The optimized ML ratio (material and solvent proportions) was 1:30 for 60 min of boiling at 80 °C under acidic medium. Use of natural and synthetic mordants produced different colour patterns giving two classes, YR, light to dark brownish colour. CuSO4, lime juice and Terminalia chebula mordants produced better wash fastness and light fastness in meta-mordant conditions. Dyeing silk with parkia peel without mordant also produces better fastness properties, thus acts as a natural substantive silk dye.
Role of Antioxidant Enzymes in Bacterial Resistance to Organic Acids
Creators: name: Hassan, H. M.
name: Azcarate-Peril, M. A.
name: Bruno-Barcena, J. M.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2010

description: Growth in aerobic environments has been shown to generate reactive oxygen species (ROS) and to cause oxidative stress in most organisms. Antioxidant enzymes (i.e., superoxide dismutases and hydroperoxidases) and DNA repair mechanisms provide protection against ROS. Acid stress has been shown to be associated with the induction of Mn superoxide dismutase (MnSOD) in Lactococcus lactis and Staphylococcus aureus. However, the relationship between acid stress and oxidative stress is not well understood. In the present study, we showed that mutations in the gene coding for MnSOD (sodA) increased the toxicity of lactic acid at pH 3.5 in Streptococcus thermophilus. The inclusion of the iron chelators 2,2′-dipyridyl (DIP), diethienetriamine-pentaacetic acid (DTPA), and O-phenanthroline (O-Phe) provided partial protection against 330 mM lactic acid at pH 3.5. The results suggested that acid stress triggers an iron-mediated oxidative stress that can be ameliorated by MnSOD and iron chelators. These findings were further validated in Escherichia coli strains lacking both MnSOD and iron SOD (FeSOD) but expressing a heterologous MnSOD from S. thermophilus. We also found that, in E. coli, FeSOD did not provide the same protection afforded by MnSOD and that hydroperoxidases are equally important in protecting the cells against acid stress. These findings may explain the ability of some microorganisms to survive better in acidified environments, as in acid foods, during fermentation and accumulation of lactic acid or during passage through the low pH of the stomach.
Analog Systems for Gravity Duals
Creators: name: Hossenfelder, S.
Publisher: name: arXiv
Year: 2014
Subjects: 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: We show that analog gravity systems exist for charged, planar black holes in asymptotic Anti-de Sitter space. These black holes have been employed to describe, via the gauge-gravity duality, strongly coupled condensed matter systems on the boundary of AdS-space. The analog gravity system is a different condensed matter system that, in a suitable limit, describes the same bulk physics as the theory on the AdS boundary. This combination of the gauge-gravity duality and analog gravity therefore suggests a duality between different condensed matter systems.
description: replaced with published version
On the boundedness of the denominators in the Zariski decomposition on surfaces
Creators: name: Bauer, Thomas
name: Pokora, Piotr
name: Schmitz, David
Publisher: name: arXiv
Year: 2014
Subjects: subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics
subject: 14A25, 14C20

description: Zariski decompositions play an important role in the theory of algebraic surfaces. For making geometric use of the decomposition of a given divisor, one needs to pass to a multiple of the divisor in order to clear denominators. It is therefore an intriguing question whether the surface has a 'universal denominator' that can be used to simultaneously clear denominators in all Zariski decompositions on the surface. We prove in this paper that, somewhat surprisingly, this condition of bounded Zariski denominators is equivalent to the bounded negativity of curves that is addressed in the Bounded Negativity Conjecture. Furthermore, we provide explicit bounds for Zariski denominators and negativity of curves in terms of each other.
description: Example 3.4 expanded; and minor edits in the text
Microbial Community Composition and Function in Permanently Cold Seawater and Sediments from an Arctic Fjord of Svalbard
Creators: name: Ziervogel, K.
name: Cox, C.
name: Arnosti, C.
name: Teske, A.
name: Durbin, A.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2011

description: ABSTRACT Heterotrophic microbial communities in seawater and sediments metabolize much of the organic carbon produced in the ocean. Although carbon cycling and preservation depend critically on the capabilities of these microbial communities, their compositions and capabilities have seldom been examined simultaneously at the same site. To compare the abilities of seawater and sedimentary microbial communities to initiate organic matter degradation, we measured the extracellular enzymatic hydrolysis rates of 10 substrates (polysaccharides and algal extracts) in surface seawater and bottom water as well as in surface and anoxic sediments of an Arctic fjord. Patterns of enzyme activities differed between seawater and sediments, not just quantitatively, in accordance with higher cell numbers in sediments, but also in their more diversified enzyme spectrum. Sedimentary microbial communities hydrolyzed all of the fluorescently labeled polysaccharide and algal extracts, in most cases at higher rates in subsurface than surface sediments. In seawater, in contrast, only 5 of the 7 polysaccharides and 2 of the 3 algal extracts were hydrolyzed, and hydrolysis rates in surface and deepwater were virtually identical. To compare bacterial communities, 16S rRNA gene clone libraries were constructed from the same seawater and sediment samples; they diverged strongly in composition. Thus, the broader enzymatic capabilities of the sedimentary microbial communities may result from the compositional differences between seawater and sedimentary microbial communities, rather than from gene expression differences among compositionally similar communities. The greater number of phylum- and subphylum-level lineages and operational taxonomic units in sediments than in seawater samples may reflect the necessity of a wider range of enzymatic capabilities and strategies to access organic matter that has already been degraded during passage through the water column. When transformations of marine organic matter are considered, differences in community composition and their different abilities to access organic matter should be taken into account.
Multiple DNA Extractions Coupled with Stable-Isotope Probing of Anthracene-Degrading Bacteria in Contaminated Soil
Creators: name: Sun, Wei
name: Singleton, David R.
name: Aitken, Michael D.
name: Jones, Maiysha D.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2011

description: ABSTRACT In many of the DNA-based stable-isotope probing (SIP) studies published to date in which soil communities were investigated, a single DNA extraction was performed on the soil sample, usually using a commercial DNA extraction kit, prior to recovering the 13 C-labeled (heavy) DNA by density-gradient ultracentrifugation. Recent evidence suggests, however, that a single extraction of a soil sample may not lead to representative recovery of DNA from all of the organisms in the sample. To determine whether multiple DNA extractions would affect the DNA yield, the eubacterial 16S rRNA gene copy number, or the identification of anthracene-degrading bacteria, we performed seven successive DNA extractions on the same aliquot of contaminated soil either untreated or enriched with [U- 13 C]anthracene. Multiple extractions were necessary to maximize the DNA yield and 16S rRNA gene copy number from both untreated and anthracene-enriched soil samples. Sequences within the order Sphingomonadales , but unrelated to any previously described genus, dominated the 16S rRNA gene clone libraries derived from 13 C-enriched DNA and were designated “anthracene group 1.” Sequences clustering with Variovorax spp., which were also highly represented, and sequences related to the genus Pigmentiphaga were newly associated with anthracene degradation. The bacterial groups collectively identified across all seven extracts were all recovered in the first extract, although quantitative PCR analysis of SIP-identified groups revealed quantitative differences in extraction patterns. These results suggest that performing multiple DNA extractions on soil samples improves the extractable DNA yield and the number of quantifiable eubacterial 16S rRNA gene copies but have little qualitative effect on the identification of the bacterial groups associated with the degradation of a given carbon source by SIP.
Local model of a qubit in the interferometric setup
Creators: name: Blasiak, Pawel
Publisher: name: arXiv
Year: 2015
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We consider a typical realization of a qubit as a single particle in two-path interferometric circuits built from phase shifters, beam splitters and detectors. This framework is often taken as a standard example illustrating various paradoxes and quantum effects, including non-locality. In this paper we show that it is possible to simulate the behaviour of such circuits in a classical manner using stochastic gates and two kinds of particles, real ones and ghosts, which interact only locally. The model has built-in limited information gain and state disturbance in measurements which are blind to ghosts. We demonstrate that predictions of the model are operationally indistinguishable from the quantum case of a qubit, and allegedly 'non-local' effects arise only on the epistemic level of description by the agent whose knowledge is incomplete due to the restricted means of investigating the system.
description: 25 pages, 7 figures. Final version as published in New Journal of Physics
Simultaneous quantitation of nine carbazole alkaloids from Murraya koenigii (L.) Spreng by 1H qNMR spectroscopy
Creators: name: Chatterjee, Debanjan
name: Narzish, Fahima
name: Borade, Prashant
name: Singh, Inder Pal
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Biophysics
subject: Biochemistry
subject: Physical Sciences not elsewhere classified
subject: Cell Biology
subject: Genetics
subject: FOS: Biological sciences
subject: Pharmacology
subject: Biotechnology
subject: Environmental Sciences not elsewhere classified
subject: Chemical Sciences not elsewhere classified
subject: Immunology
subject: FOS: Clinical medicine
subject: Mathematical Sciences not elsewhere classified
subject: Developmental Biology

description: Murraya koenigii leaves are widely used as a spice and also have several biological activities. The major active constituents are carbazole alkaloids. Quantitation by HPLC or HPTLC requires pure marker compounds, whereas nuclear magnetic resonance spectroscopy can be used as a quantitative technique without the requirement of a pure marker compound. An alkaloid-rich fraction was prepared from the leaves and a validated qNMR method was developed for the quantitation of nine carbazole alkaloids, namely mahanimbine, girinimbine, koenimbine, koenine, kurrayam, mukonicine, isomahanimbine, euchristine B and bismahanine. One of the major compounds, koenimbine, was isolated and quantified by HPTLC to compare the results. The results obtained by qNMR were compared with the reported yields of these compounds.
Galois Transformers and Modular Abstract Interpreters
Creators: name: Darais, David
name: Might, Matthew
name: Van Horn, David
Publisher: name: arXiv
Year: 2014
Subjects: subject: Programming Languages (cs.PL)
subject: FOS: Computer and information sciences
subject: F.3.2

description: The design and implementation of static analyzers has become increasingly systematic. Yet for a given language or analysis feature, it often requires tedious and error prone work to implement an analyzer and prove it sound. In short, static analysis features and their proofs of soundness do not compose well, causing a dearth of reuse in both implementation and metatheory. We solve the problem of systematically constructing static analyzers by introducing Galois transformers: monad transformers that transport Galois connection properties. In concert with a monadic interpreter, we define a library of monad transformers that implement building blocks for classic analysis parameters like context, path, and heap (in)sensitivity. Moreover, these can be composed together independent of the language being analyzed. Significantly, a Galois transformer can be proved sound once and for all, making it a reusable analysis component. As new analysis features and abstractions are developed and mixed in, soundness proofs need not be reconstructed, as the composition of a monad transformer stack is sound by virtue of its constituents. Galois transformers provide a viable foundation for reusable and composable metatheory for program analysis. Finally, these Galois transformers shift the level of abstraction in analysis design and implementation to a level where non-specialists have the ability to synthesize sound analyzers over a number of parameters.
description: OOPSLA '15, October 25-30, 2015, Pittsburgh, PA, USA
Forensics of Subhalo-Stream Encounters: The Three Phases of Gap Growth
Creators: name: Erkal, Denis
name: Belokurov, Vasily
Publisher: name: arXiv
Year: 2014
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: There is hope to discover dark matter subhalos free of stars (predicted by the current theory of structure formation) by observing gaps they produce in tidal streams. In fact, this is the most promising technique for dark substructure detection and characterization as such gaps grow with time, magnifying small perturbations into clear signatures observable by ongoing and planned Galaxy surveys. To facilitate such future inference, we develop a comprehensive framework for studies of the growth of the stream density perturbations. Starting with simple assumptions and restricting to streams on circular orbits, we derive analytic formulae that describe the evolution of all gap properties (size, density contrast etc) at all times. We uncover complex, previously unnoticed behavior, with the stream initially forming a density enhancement near the subhalo impact point. Shortly after, a gap forms due to the relative change in period induced by the subhalo's passage. There is an intermediate regime where the gap grows linearly in time. At late times, the particles in the stream overtake each other, forming caustics, and the gap grows like $\sqrt{t}$. In addition to the secular growth, we find that the gap oscillates as it grows due to epicyclic motion. We compare this analytic model to N-body simulations and find an impressive level of agreement. Importantly, when analyzing the observation of a single gap we find a large degeneracy between the subhalo mass, the impact geometry and kinematics, the host potential and the time since flyby.
description: 14 pages and 13 figures. Minor corrections. Accepted to MNRAS. Links to movies of stream gaps in the conclusions
Promoting columnar-to-equiaxed transition in AlCoCrFeNi high entropy alloy during selective laser melting by adding Cr3C2
Creators: name: Pan, Xingyu
name: Qiu, Chunlei
Publisher: name: Taylor & Francis
Year: 2022
Subjects: subject: Biochemistry
subject: Space Science
subject: Cell Biology
subject: Genetics
subject: FOS: Biological sciences
subject: Molecular Biology
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Ecology
subject: 69999 Biological Sciences not elsewhere classified
subject: 110309 Infectious Diseases
subject: FOS: Health sciences

description: The 5 at% Cr3C2 particles were mixed with AlCoCrFeNi high entropy alloy powder particles and then selectively laser melted. The addition caused full columnar-to-equiaxed grain transition (CET) and significant grain refinement. The inter-dendritic regions and grain boundaries (GBs) of the as-fabricated sample were segregated with Cr and C, which led to the formation of an FCC belt/network structure along GBs. The grain interior was dominated by BCC/B2 and sporadically decorated by Cr7C3 particles. The partitioning of Cr and C into liquid ahead of the solidification front, which may have generated significant constitutional supercooling, is believed to be responsible for the full CET. The present study introduces a small fraction of Cr3C2 particles into AlCoCrFeNi high entropy alloy and successfully enables full columnar-to-equiaxed grain transition and significant grain refinement during selective laser melting.
Turbulence Reduces Magnetic Diffusivity in a Liquid Sodium Experiment
Creators: name: Cabanes, Simon
name: Schaeffer, Nathanaël
name: Nataf, Henri-Claude
Publisher: name: arXiv
Year: 2014
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Classical Physics (physics.class-ph)
subject: FOS: Physical sciences

description: The contribution of small scale turbulent fluctuations to the induction of mean magnetic field is investigated in our liquid sodium spherical Couette experiment with an imposed magnetic field.An inversion technique is applied to a large number of measurements at $Rm \approx 100$ to obtain radial profiles of the $α$ and $β$ effects and maps of the mean flow.It appears that the small scale turbulent fluctuations can be modeled as a strong contribution to the magnetic diffusivity that is negative in the interior region and positive close to the outer shell.Direct numerical simulations of our experiment support these results.The lowering of the effective magnetic diffusivity by small scale fluctuations implies that turbulence can actually help to achieve self-generation of large scale magnetic fields.
description: Rajout d'un erratum
Norovirus Infectivity in Humans and Persistence in Water
Creators: name: Leon, Juan S.
name: Abdulhafid, Gwen
name: Fernandez, Marina L.
name: Seitz, Scot R.
name: Lyon, G. Marshall
name: McDaniels, Marisa
name: Schwab, Kellogg J.
name: Lindesmith, Lisa C.
name: Dowd, Melissa
name: Baric, Ralph S.
name: Moe, Christine L.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2011

description: ABSTRACT To examine the long-term infectivity of human norovirus in water, 13 study subjects were challenged at different time points with groundwater spiked with the prototype human norovirus, Norwalk virus. Norwalk virus spiked in groundwater remained infectious after storage at room temperature in the dark for 61 days (the last time point tested). The Norwalk virus-seeded groundwater was stored for 1,266 days and analyzed, after RNase treatment, by reverse transcription-quantitative PCR (RT-qPCR) to detect Norwalk virus RNA contained within intact capsids. Norwalk virus RNA within intact capsids was detected in groundwater for 1,266 days, with no significant log 10 reduction throughout 427 days and a significant 1.10-log 10 reduction by day 1266. Purified Norwalk virus RNA (extracted from Norwalk virus virions) persisted for 14 days in groundwater, tap water, and reagent-grade water. This study demonstrates that Norwalk virus in groundwater can remain detectable for over 3 years and can remain infectious for at least 61 days. (ClinicalTrials.gov identifier NCT00313404.)
Stable Isotope Probing of an Algal Bloom To Identify Uncultivated Members of the Rhodobacteraceae Associated with Low-Molecular-Weight Polycyclic Aromatic Hydrocarbon Degradation
Creators: name: Singleton, David R.
name: Aitken, Michael D.
name: Semple, Kirk T.
name: Gutierrez, Tony
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2011

description: ABSTRACT Polycyclic aromatic hydrocarbon (PAH)-degrading bacteria associated with an algal bloom in Tampa Bay, FL, were investigated by stable isotope probing (SIP) with uniformly labeled [ 13 C]naphthalene. The dominant sequences in clone libraries constructed from 13 C-enriched bacterial DNA (from naphthalene enrichments) were identified as uncharacterized members of the family Rhodobacteraceae . Quantitative PCR primers targeting the 16S rRNA gene of these uncultivated organisms were used to determine their abundance in incubations amended with unlabeled naphthalene and phenanthrene, both of which showed substantial increases in gene copy numbers during the experiments. As demonstrated by this work, the application of uniformly 13 C-labeled PAHs in SIP experiments can successfully be used to identify novel PAH-degrading bacteria in marine waters.
Time correlation functions for non-Hermitian quantum systems
Creators: name: Sergi, Alessandro
name: Zloshchastiev, Konstantin G.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Quantum Physics (quant-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We introduce a formalism for time-dependent correlation functions for systems whose evolutions are governed by non-Hermitian Hamiltonians of general type. It turns out that one can define two different types of time correlation functions. Both these definitions seem to be physically consistent while becoming equivalent only in certain cases. Moreover, when autocorrelation functions are considered, one can introduce another function defined as the relative difference between the two definitions. We conjecture that such a function can be used to assess the positive semi-definiteness of the density operator without computing its eigenvalues. We illustrate these points by studying analytically a number of models with two energy levels.
description: final version
Chemical composition and anti-inflammatory activity of flower essential oil from Forsythia koreana Nakai
Creators: name: Yang, Xiao-nan
name: Qin, Ben
name: Li, Hong-mei
name: Miao, Jian-hua
name: Kang, Sun-chul
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Biochemistry
subject: Genetics
subject: FOS: Biological sciences
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: Developmental Biology

description: Forsythia koreana Nakai is an ornamental plant widely cultivated in East Asia. The essential oil of F. koreana flowers (FEO) was extracted by hydrodistillation process and the volatile components were determined with gas chromatography coupled with mass spectrometry. The anti-inflammatory activity of FEO was investigated by using TPA-induced mouse ear inflammation model. The major components of FEO were identified as n-tetracosane (29.85%), n-heneicosane (17.45%), myristic acid (8.46%) and palmitaldehyde (6.22%). The TPA-induced mouse ear edema, water content, dermis thickness, epidermis thickness and nitric oxide production were decreased by FEO. Our findings suppose that the flower essential oil of F. koreana exerted anti-inflammatory activity, and may be used in the development of anti-inflammatory products in future.
Apparent Loss of Vibrio vulnificus from North Carolina Oysters Coincides with a Drought-Induced Increase in Salinity
Creators: name: Oliver, James D.
name: Noble, Rachel T.
name: Williams, Tiffany C.
name: Froelich, Brett A.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2012

description: ABSTRACT Despite years of successful isolation of Vibrio vulnificus from estuarine waters, beginning in 2007, it was extremely difficult to culture V. vulnificus from either North Carolina estuarine water or oyster samples. After employing culture-based methods as well as PCR and quantitative PCR for the detection of V. vulnificus , always with negative results, we concluded that this pathogen had become nearly undetectable in the North Carolina estuarine ecosystem. We ensured that the techniques were sound by seeding North Carolina oysters with V. vulnificus and performing the same tests as those previously conducted on unadulterated oysters. V. vulnificus was readily detected in the seeded oysters using both classes of methods. Furthermore, oysters were obtained from the Gulf of Mexico, and V. vulnificus was easily isolated, confirming that the methodology was sound but that the oysters and waters of North Carolina were lacking the V. vulnificus population studied for decades. Strikingly, the apparent loss of detectable V. vulnificus coincided with the most severe drought in the history of North Carolina. The drought continued until the end of 2009, with an elevated water column salinity being observed throughout this period and with V. vulnificus being nearly nonexistent. When salinities returned to normal after the drought abated in 2010, we were again able to routinely isolate V. vulnificus from the water column, although we were still unable to culture it from oysters. We suggest that the oysters were colonized with a more salt-tolerant bacterium during the drought, which displaced V. vulnificus and may be preventing recolonization.
Correlation between Quantitative PCR and Culture-Based Methods for Measuring Enterococcus spp. over Various Temporal Scales at Three California Marine Beaches
Creators: name: Weisberg, Stephen B.
name: Schiff, Kenneth C.
name: Converse, Reagan R.
name: Haugland, Richard A.
name: Griffith, John F.
name: Noble, Rachel T.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2012

description: ABSTRACT Several studies have examined how fecal indicator bacteria (FIB) measurements compare between quantitative PCR (qPCR) and the culture methods it is intended to replace. Here, we extend those studies by examining the stability of that relationship within a beach, as affected by time of day and seasonal variations in source. Enterococcus spp. were quantified at three southern California beaches in the morning and afternoon using two qPCR assays, membrane filtration, and defined-substrate testing. While qPCR and culture-based measurements were consistently and significantly correlated, strength of the correlation varied both among and within beaches. Correlations were higher in the morning (0.45 < ρ < 0.74 [ P < 0.002]) than in the afternoon (0.18 < ρ < 0.45 [ P < 0.021]) and higher when the fecal contamination was concentrated (0.38 < ρ < 0.83 [ P < 0.001]) than when it was diffuse (0.19 < ρ < 0.34 [ P < 0.003]). The ratios of culture-based and qPCR results (CFU or most probable number [MPN] per calibrator cell equivalents [CCE]) also varied spatially and temporally. Ratios ranged between 0.04 and 0.85 CFU or MPN per CCE and were lowest at the beach affected by diffuse pollution. Patterns in the ratios over the course of the day were dissimilar across beaches, increasing with time at one beach and decreasing at another. The spatial and temporal variability we observed indicate that the empirical relationship between culture-based and qPCR results is not universal, even within a beach.
Flavonoids from Pistacia chinensis subsp. integerrima with leishmanicidal activity: computational and experimental evidence
Creators: name: Rauf, Abdur
name: Rashid, Umer
name: Shbeer, Abdullah Muhammad
name: Al-Ghorbani, Mohammed
name: Muhammad, Naveed
name: Khalil, Anees Ahmed
name: Naz, Humaira
name: Sharma, Rohit
name: Ribaudo, Giovanni
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Biochemistry
subject: Pharmacology
subject: Biotechnology
subject: Chemical Sciences not elsewhere classified
subject: Immunology
subject: FOS: Clinical medicine
subject: Biological Sciences not elsewhere classified
subject: Information Systems not elsewhere classified
subject: Plant Biology
subject: FOS: Biological sciences

description: Pistacia chinensis subsp. integerrima is a valuable medicinal plant as its parts and extracts found application for treating diarrhea, fever, liver disorders, asthma, and inflammation. In this study, we report the leishmanicidal activity of sakuranetin, spinacetin, and patuletin extracted from P. chinensis. The tested compounds revealed a strong anti-leishmanial activity in vitro against Leishmania major showing IC50 values of 7.98 ± 0.16 µM, 9.23 ± 0.23 µM 11.09 ± 0.87 µM for sakuranetin, spinacetin, and patuletin, respectively. Moreover, to explore the potential mechanism(s) by which the compounds may act, computational docking studies were performed against dihydrofolate reductase and pteridine reductase, showing that the flavonoids could target these two key enzymes to exploit their leishmanicidal activity. In accordance with in vitro results, patuletin was highlighted as the most promising compound of the set, and binding energy values of −6.72 and −6.74 kcal/mol were computed for the two proteins, respectively.
Overcoming the strength-ductility trade-off in refractory medium-entropy alloys via controlled B2 ordering
Creators: name: Yurchenko, N.
name: Panina, E.
name: Tojibaev, A.
name: Zherebtsov, S.
name: Stepanov, N.
Publisher: name: Taylor & Francis
Year: 2022
Subjects: subject: Biochemistry
subject: Space Science
subject: 29999 Physical Sciences not elsewhere classified
subject: FOS: Physical sciences
subject: Medicine
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Cancer

description: Herein, we showed that controlled additions of Al, which provided a certain degree of B2 ordering, resulted in a ∼ 37%-enhancement of both yield strength and uniform elongation in Alx(NbTiZr)100-x (x = 0; 2.5; 5; 7.5 at.%) refractory medium-entropy alloys. The improvement of properties stemmed from the solid solution and short-range order strengthening, as well as from the alteration in a character of dislocation glide. The B2 ordering caused the formation of multiple dislocation bands and the activation of cross-slip, which improved the macroscopic stability of plastic flow and extended the strengthening stage, thereby postponing necking. Controlled Al-induced B2 ordering helps overcome the strength-ductility dilemma in refractory medium-entropy alloys due to solid solution and short-range strengthening coupled with the dislocation motion changing.
Tuneable defect interactions and supersolidity in dipolar quantum gases on a lattice potential
Creators: name: Lechner, Wolfgang
name: Cinti, Fabio
name: Pupillo, Guido
Publisher: name: arXiv
Year: 2015
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Point defects in self-assembled crystals, such as vacancies and interstitials, attract each other and form stable clusters. This leads to a phase separation between perfect crystalline structures and defect conglomerates at low temperatures. We propose a method that allows one to tune the effective interactions between point defects from attractive to repulsive by means of external periodic fields. In the quantum regime, this allows one to engineer strongly-correlated many-body phases. We exemplify the microscopic mechanism by considering dipolar quantum gases of ground state polar molecules and weakly bound molecules of strongly magnetic atoms trapped in a weak optical lattice in a two-dimensional configuration. By tuning the lattice depth, defect interactions turn repulsive, which allows us to deterministically design a novel supersolid phase in the continuum limit.
description: 6 pages, 5 figures
Heterologous Expression of Polycyclic Aromatic Hydrocarbon Ring-Hydroxylating Dioxygenase Genes from a Novel Pyrene-Degrading Betaproteobacterium
Creators: name: Aitken, Michael D.
name: Singleton, David R.
name: Hu, Jing
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2012

description: ABSTRACT A betaproteobacterium within the family Rhodocyclaceae previously identified as a pyrene degrader via stable-isotope probing (SIP) of contaminated soil (designated pyrene group 1 or PG1) was cultivated as the dominant member of a mixed bacterial culture. A metagenomic library was constructed, and the largest contigs were analyzed for genes associated with polycyclic aromatic hydrocarbon (PAH) metabolism. Eight pairs of genes with similarity to the α- and β-subunits of ring-hydroxylating dioxygenases (RHDs) associated with aerobic bacterial PAH degradation were identified and linked to PG1 through PCR analyses of a simplified enrichment culture. In tandem with a ferredoxin and reductase found in close proximity to one pair of RHD genes, six of the RHDs were cloned and expressed in Escherichia coli . Each cloned RHD was tested for activity against nine PAHs ranging in size from two to five rings. Despite differences in their predicted protein sequences, each of the six RHDs was capable of transforming phenanthrene and pyrene. Three RHDs could additionally transform naphthalene and fluorene, and these genotypes were also associated with the ability of the E. coli constructs to convert indole to indigo. Only one of the six cloned RHDs was capable of transforming anthracene and benz[ a ]anthracene. None of the tested RHDs were capable of significantly transforming fluoranthene, chrysene, or benzo[ a ]pyrene.
Direitos autorais dos dados de pesquisa
Creators: name: Matos, Igor Yure Ramos
name: Júnior, Divino Ignácio Ribeiro
Publisher: name: Zenodo
Year: 2022

description: Apresentação realizada na sessão O meu Póster em 40 segundos da 13ª Conferência Lusófona de Ciência Aberta, formato híbrido, de 10 a 12 de outubro de 2022.
Porticoccus hydrocarbonoclasticus sp. nov., an Aromatic Hydrocarbon-Degrading Bacterium Identified in Laboratory Cultures of Marine Phytoplankton
Creators: name: Nichols, Peter D.
name: Whitman, William B.
name: Gutierrez, Tony
name: Aitken, Michael D.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2012

description: ABSTRACT A marine bacterium, designated strain MCTG13d, was isolated from a laboratory culture of the dinoflagellate Lingulodinium polyedrum CCAP1121/2 by enrichment with polycyclic aromatic hydrocarbons (PAHs) as the sole carbon source. Based on 16S rRNA gene sequence comparisons, the strain was most closely related to Porticoccus litoralis IMCC2115 T (96.5%) and to members of the genera Microbulbifer (91.4 to 93.7%) and Marinimicrobium (90.4 to 92.0%). Phylogenetic trees showed that the strain clustered in a distinct phyletic line in the class Gammaproteobacteria for which P. litoralis is presently the sole cultured representative. The strain was strictly aerobic, rod shaped, Gram negative, and halophilic. Notably, it was able to utilize hydrocarbons as sole sources of carbon and energy, whereas sugars did not serve as growth substrates. The predominant isoprenoid quinone of strain MCTG13d was Q-8, and the dominant fatty acids were C 16:1ω7c , C 18:1ω7c , and C 16:0 . DNA G+C content for the isolate was 54.9 ± 0.42 mol%. Quantitative PCR primers targeting the 16S rRNA gene of this strain showed that this organism was common in other laboratory cultures of marine phytoplankton. On the basis of phenotypic and genotypic characteristics, strain MCTG13d represents a novel species of Porticoccus , for which the name Porticoccus hydrocarbonoclasticus sp. nov. is proposed. The discovery of this highly specialized hydrocarbon-degrading bacterium living in association with marine phytoplankton suggests that phytoplankton represent a previously unrecognized biotope of novel bacterial taxa that degrade hydrocarbons in the ocean.
The chemical composition of the aerial parts essential oil of Phagnalon sinaicum collected in the Negev Desert (Israel)
Creators: name: Badalamenti, Natale
name: Porrello, Antonella
name: Merra, Rosalia
name: Ilardi, Vincenzo
name: Bruno, Maurizio
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Biochemistry
subject: Genetics
subject: FOS: Biological sciences
subject: Molecular Biology
subject: Pharmacology
subject: Environmental Sciences not elsewhere classified
subject: Chemical Sciences not elsewhere classified
subject: Ecology
subject: Biological Sciences not elsewhere classified
subject: Hematology
subject: Plant Biology

description: The genus Phagnalon Cass. (Asteraceae) is widely distributed from Macaronesia in the West to the Himalayas in the East, from South France and Nord Italy to Ethiopia and Arabian Peninsula. Species of this genus have been used in folk medicine of many countries as medicinal herbs and they are also used such as food. The extracts and the essential oils (EOs) of these plants have reported antimicrobial, antioxidant, antidiabetic, antitumor, etc. properties and they have different biological applications. Phagnalon sinaicum Bornm. and Kneuck. is a very rare plant native of Middle East. It grows primarily in the desert or dry scrubland biome. Its EO, never previously investigated, was analysed by GC-MS. The EO was very rich in oxygenated monoterpenes, with artemisia ketone (20.40%), α-thujone (19.36%), and santolina alcohol (13.29%) as main constituent. Some considerations with respect to all the other EOs of Phagnalon taxa studied so far were carried out.
Fuzzy Adaptive Resonance Theory, Diffusion Maps and their applications to Clustering and Biclustering
Creators: name: Damelin, S. B.
name: Gu, Y.
name: Wunsch, D. C.
name: Xu, R.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Neural and Evolutionary Computing (cs.NE)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences
subject: 94A15, 62H30, 60J20, 68T05, 68T45, 68T10

description: In this paper, we describe an algorithm FARDiff (Fuzzy Adaptive Resonance Dif- fusion) which combines Diffusion Maps and Fuzzy Adaptive Resonance Theory to do clustering on high dimensional data. We describe some applications of this method and some problems for future research.
description: Accepted in Math.Model.Nat.Phenom
TetR-Based Gene Regulation Systems for Francisella tularensis
Creators: name: Miller, Cheryl N.
name: LoVullo, Eric D.
name: Kawula, Thomas H.
name: Pavelka, Martin S.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2012

description: ABSTRACT There are a number of genetic tools available for studying Francisella tularensis , the etiological agent of tularemia; however, there is no effective inducible or repressible gene expression system. Here, we describe inducible and repressible gene expression systems for F. tularensis based on the Tet repressor, TetR. For the inducible system, a tet operator sequence was cloned into a modified F. tularensis groESL promoter sequence and carried in a plasmid that constitutively expressed TetR. To monitor regulation the luminescence operon, luxCDABE , was cloned under the hybrid Francisella tetracycline-regulated promoter ( FTRp ), and transcription was initiated with addition of anhydrotetracycline (ATc), which binds TetR and alleviates TetR association with tetO. Expression levels measured by luminescence correlated with ATc inducer concentrations ranging from 20 to 250 ng ml −1 . In the absence of ATc, luminescence was below the level of detection. The inducible system was also functional during the infection of J774A.1 macrophages, as determined by both luminescence and rescue of a mutant strain with an intracellular growth defect. The repressible system consists of FTRp regulated by a reverse TetR mutant (revTetR), TetR r1.7. Using this system with the lux reporter, the addition of ATc resulted in decreased luminescence, while in the absence of ATc the level of luminescence was not significantly different from that of a construct lacking TetR r1.7. Utilizing both systems, the essentiality of SecA, the protein translocase ATPase, was confirmed, establishing that they can effectively regulate gene expression. These two systems will be invaluable in exploring F. tularensis protein function.