julilili42/papers huggingface dataset:
Spectral analysis of the extremely hot DA white dwarf PG 0948+534
2018-12-14

There is a striking paucity of hydrogen-rich (DA) white dwarfs (WDs) relative to their hydrogen-deficient (non-DA) counterparts at the very hot end of the WD cooling sequence. The three hottest known DAs (surface gravity log g 7.0) have effective temperatures around Teff = 140,000 K, followed by only five objects in the range 104,000 - 120,000 K. They are by far outnumbered by forty non-DAs with Teff = 100,000 - 250,000 K, giving a DA/non-DA ratio of 0.2. In contrast, this ratio is the inverse of that for the cooler WDs. One reason for this discrepancy could be uncertainties in the temperature determination of hot DAs using Balmer-line spectroscopy. Recent investigations involving metal-ionization balances in ultraviolet (UV) spectra indeed showed that the temperatures of some DAs were underestimated, but the paucity of extremely hot DAs prevailed. Here we present the results of a UV spectral analysis of one of the three hottest DAs, PG0948+534. We find that its temperature was strongly overestimated by recent Balmer line analyses. We correct it downward to 105,000 5000 K, aggravating the hot-DA paucity. The Balmer-line problem encountered previously is not resolved by our non-LTE line-blanketed model atmospheres. We speculate that it might be related to the possible presence of a magnetosphere. This is supported by the V-band variability that shows a period of P=3.45 d (amplitude 0.19 mag), which we interpret as the star's rotation period. The metal abundances in PG0948+534 are affected by atomic diffusion and we conclude that the onset of diffusion in hot DAs occurs when they cool below Teff about 105,000 K. We discuss the possibility that the paucity of very hot DAs is a consequence of their fast evolutionary rate.
Line-driven ablation of circumstellar discs – IV. The role of disc ablation in massive star formation and its contribution to the stellar upper mass limit
2018-12-14

Abstract Radiative feedback from luminous, massive stars during their formation is a key process in moderating accretion on to the stellar object. In the prior papers in this series, we showed that one form such feedback takes is UV line-driven disc ablation. Extending on this study, we now constrain the strength of this effect in the parameter range of star and disc properties appropriate to forming massive stars. Simulations show that ablation rate depends strongly on stellar parameters, but that this dependence can be parameterized as a nearly constant, fixed enhancement over the wind mass-loss rate, allowing us to predict the rate of disc ablation for massive (proto)stars as a function of stellar mass and metallicity. By comparing this to predicted accretion rates, we conclude that ablation is a strong feedback effect for very massive (proto)stars which should be considered in future studies of massive star formation.
Titanium(IV) Catecholate‐Grafted Mesoporous Silica KIT‐6: Probing Sequential and Convergent Immobilization Approaches
2018-12-14

Molecular Ti IV catecholates were obtained as dimeric complexes from protonolysis reactions of Ti(NMe 2 ) 4 with pyrocatechol (H 2 CAT), 4‐ tert ‐butylcatechol (H 2 CAT t Bu‐4), 3,5‐di‐ tert ‐butylcatechol (H 2 CAT t Bu 2 –3,5), 2,3‐dihydroxynaphthalene (H 2 DHN) and 3,6‐di ‐tert ‐butylcatechol (H 2 CAT t Bu 2 –3,6). The heteroleptic monocatecholate amide complexes were characterized by X‐ray structure analysis but only [Ti(CAT)(NMe 2 ) 2 ] 2 and [Ti(DHN)(NMe 2 ) 2 ] 2 were obtained as pure compounds. The solid‐state structures revealed Ti IV centers bridged by two catecholato ligands adopting a [κ 2 (O,μ‐O′)] coordination mode except for complex [Ti(CAT t Bu 2 –3,6)(NMe 2 ) 2 ] featuring one bridging catecholato and one bridging amido ligand. Heteroleptic complex [Ti(DHN)(NMe 2 ) 2 ] 2 was grafted onto large‐pore periodic mesoporous silica KIT‐6 ( convergent approach ) and the resulting Ti IV surface species compared with the established sequential approach , i.e., grafting of Ti(NMe 2 ) 4 onto the KIT‐6 material and subsequent ligand exchange with H 2 DHN. Dimeric complex [Ti(DHN)(NMe 2 ) 2 ] 2 proved to be sufficiently reactive for a direct grafting yielding the same dominant surface species as obtained according to the sequential approach, as revealed by nitrogen physisorption, elemental analysis, and DRIFT/ 13 C CP MAS spectroscopy.
From substrate to soil in a pristine environment – pedochemical, micromorphological and microbiological properties from soils on James Ross Island, Antarctica
2018-12-14

Abstract. James Ross Island (JRI) offers the exceptional opportunity to study pedogenesis without the influence of vascular plants or faunal activities (e.g. penguin rookeries) in a landscape marking the transition from maritime to continental Antarctica. Here, primarily microbial communities control soil biological processes and affect soil chemical and physical properties in a semiarid region with mean annual precipitation from 200 to 500 mm and mean air temperature below 0 °C. The impact of climate change on soil forming processes in this part of Antarctica and its related microbial processes is unknown. In this study, two soil profiles from JRI (one at St. Martha Cove – SMC, and another at Brandy Bay – BB) were investigated by combining pedological, geochemical and microbiological methods. The soil profiles are similar in respect to topographic position and parent material but are spatially separated by an orographic barrier and therefore represent lee- and windward locations towards the mainly south-westerly winds. Opposing trends in the depth functions of pH and differences in EC-values are caused by additional input of bases by sea spray at BB, the site close to the Prince Gustav Channel. Both soils are classified as Cryosols, dominated by bacterial taxa such as Actinobacteria, Proteobacteria, Acidobacteria, Gemmatimonadates and Chloroflexi. A shift in the dominant taxa in both soils and an increased abundance of multiple operational taxonomic units (OTUs) related to potential chemolithoautotrophic Acidoferrobacteraceae was observed. This shift was accompanied by a change in soil microstructure below 20 cm depth, with potential impact on water availability and matter fluxes. Multivariate statistics revealed correlations between the microbial community structure and soil parameters such as chloride, sulfate, calcium and organic carbon contents, grain size distribution, as well as the pedogenic oxide ratio.
Dramatic spectral transition of X-ray pulsar GX 304−1 in low luminous state
2018-12-15

Abstract We report on the discovery of a dramatic change in the energy spectrum of the X-ray pulsar GX 304−1 appearing at low luminosity. Particularly, we found that the cut-off power-law spectrum typical for accreting pulsars, including GX 304−1 at higher luminosities of LX ∼ 1036–1037 erg s−1, transformed at lower luminosity of LX ∼ 1034 erg s−1 to a two-component spectrum peaking around 5 and 40 keV. We suggest that the observed transition corresponds to a change of the dominant mechanism responsible for the deceleration of the accretion flow. We argue that the accretion flow energy at low accretion rates is released in the atmosphere of the neutron star, and the low-energy component in the source spectrum corresponds to the thermal emission of the optically thick, heated atmospheric layers. The most plausible explanations for the high-energy component are either the cyclotron emission reprocessed by the magnetic Compton scattering or the thermal radiation of deep atmospheric layers partly Comptonized in the overheated upper layers. Alternative scenarios are also discussed.
Pandora's box of binary tungsten iodides
2018-12-15

More than 20 binary tungsten iodides have been discovered. This was possible due to a new synthesis of W<sub>3</sub>I<sub>12</sub> through halide exchange reaction and by thermal scanning. Depending on the I<sub>2</sub> partial pressure compounds can incorporate or release I<sub>2</sub>. On heating they undergo self-reduction. Some tungsten iodide clusters can be directly transferred into solution.
Nasal insulin administration does not affect hepatic glucose production at systemic fasting insulin levels
2018-12-15

Aims To evaluate the effects of brain insulin on endogenous glucose production in fasting humans, with a focus on hepatic glucose release by performing a randomized, placebo‐controlled, blinded, crossover experiment. Materials and methods On two separate days, 2 H 2 ‐glucose was infused to nine healthy lean men, and blood was sampled from the hepatic vein and a radial artery. On day 1, participants received 160 U human insulin through nasal spray, and on day 2 they received placebo spray, together with an intravenous insulin bolus to mimic spillover of nasal insulin to the circulation. Hepatic glucose fluxes and endogenous glucose production were calculated. Results Plasma insulin concentrations were similar on the two study days, and no differences in whole‐body endogenous glucose production or hepato‐splanchnic glucose turnover were detected. Conclusions Nasal administration of insulin does not influence whole‐body or hepatic glucose production in fasting humans. By contrast, pharmacological delivery of insulin to the brain might modulate insulin effectiveness in glucose‐producing tissue when circulating insulin levels are elevated; therefore, the metabolic consequences of brain insulin action appear to be dependent on metabolic prandial status.
The coordinative flexibility of rigid phenanthroline-analogous di(NHC)-ligands
2018-12-15

Abstract In 2010 we have introduced a new N-N connected 1,4-dicarbene ligand named ‘vegi’ based on an imidazo-anellated pyridazine (Kunz et al., 2010) [1]. Although the tricyclic ligand resembles 1,10-phenanthroline, the dicarbene ligand turned out to be much more flexible. It can serve as a chelating as well as a bridging ligand. In addition, the electronic properties (strongly electron-donating) are distinct from 1,10-phenanthroline or 2,2′-bipyridine. This review comprises the synthesis, electronic properties, the coordination chemistry as well as the reactivity of this remarkable ligand and its complexes.
Primary Controls on the Natural Denitrification Potential of Aquifers
2018-12-16

Elevated nitrate concentrations in groundwater are observed in regions of intensive agriculture worldwide, threatening the safety of drinking-water production. Aquifers may contain geogenic reduced constituents, such as natural organic matter (NOM), pyrite, or biotite, facilitating aerobic respiration and denitrification. Because these electron donors are not replenished, the breakthrough of nitrate (and eventually dissolved oxygen) in production wells is only delayed. Frameworks of modeling nitrate fate and transport that assume constant rate coefficients of nitrate elimination cannot address the reduction of the aquifer’s denitrification potential by the reaction itself. We have tested several approaches of modeling the fate of dissolved oxygen and nitrate in aquifers, including multi-dimensional bioreactive transport models with dynamic abundances of aerobic and denitrifying bacteria, approaches neglecting the dynamics of biomass and dispersive mixing, and simple models based on an electron balance. We found that the primary control on the timing of nitrate breakthrough is the ratio of the bioavailable electron-donor content in the aquifer material to the electron-acceptor load in the infiltrating water. Combined spatial variability of groundwater velocities and electron-donor content can explain most of the spread in nitrate breakthrough, whereas kinetics of the reaction plays a minor role under most conditions. Our modeling study highlights the need for field surveys on joined physical and chemical heterogeneity of aquifers under the stress of pollutants that can react with the aquifer material.
Gain-of-Function Mutations in the Phospholipid Flippase MprF Confer Specific Daptomycin Resistance
2018-12-17

Ever since daptomycin was introduced to the clinic, daptomycin-resistant isolates have been reported. In most cases, the resistant isolates harbor point mutations in MprF, which produces and flips the positively charged phospholipid LysPG. This has led to the assumption that the resistance mechanism relies on the overproduction of LysPG, given that increased LysPG production may lead to increased electrostatic repulsion of positively charged antimicrobial compounds, including daptomycin. Here we show that the resistance mechanism is highly specific and relies on a different process that involves a functional MprF flippase, suggesting that the resistance-conferring mutations may enable the flippase to accommodate daptomycin or an unknown component that is crucial for its activity. Our report provides a new perspective on the mechanism of resistance to a major antibiotic.
Cross-Coupling of Chloro(hetero)arenes with Thiolates Employing a Ni(0)-Precatalyst
2018-12-17

A general and efficient Ni-catalyzed coupling of challenging aryl chlorides and in situ generated aliphatic and aromatic thiolates is described. The employed on-cycle, air-stable defined Ni precatalysts allow for transformation of a broad scope of substrates. A variety of functional groups and heterocyclic motifs as well as structurally varied thiols are tolerated at unprecedented moderate catalyst loadings and reaction temperatures. Depending on reaction conditions, aryl thiols can selectively undergo C-S or C-C couplings.
A Step towards Integrating CMORPH Precipitation Estimation with Rain Gauge Measurements
2018-12-17

Accurate daily rainfall estimation is required in several applications such as in hydrology, hydrometeorology, water resources management, geomorphology, civil protection, and agriculture, among others. CMORPH daily rainfall estimations were integrated with rain gauge measurements in Brazil between 2000 and 2015, in order to reduce daily rainfall estimation errors by means of the statistical objective analysis scheme (SOAS). Early comparisons indicated high discrepancies between daily rain gauge rainfall measurements and respective CMORPH areal rainfall accumulation estimates that tended to be reduced with accumulation time span (e.g., yearly accumulation). Current results show CMORPH systematically underestimates daily rainfall accumulation along the coastal areas. The normalized error variance (NEXERVA) is higher in sparsely gauged areas at Brazilian North and Central-West regions. Monthly areal rainfall averages and standard deviation were obtained for eleven Brazilian watersheds. While an overall negative tendency (3 mm·h −1 ) was estimated, the Amazon watershed presented a long-term positive tendency. Monthly areal mean precipitation and respective spatial standard deviation closely follow a power-law relationship for data-rich watersheds, i.e., with denser rain gauge networks. Daily SOAS rainfall accumulation was also used to calculate the spatial distribution of frequencies of 3-day rainfall episodes greater than 100 mm. Frequencies greater than 3% were identified downwind of the Peruvian Andes, the Bolivian Amazon Basin, and the La Plata Basin, as well as along the Brazilian coast, where landslides are recurrently triggered by precipitation.
Understanding the Formation of Conductive Mesocrystalline Superlattices with Cubic PbS Nanocrystals at the Liquid/Air Interface
2018-12-17

We report the formation of conductive mesocrystalline superstructures of cubic PbS nanocrystals (NCs) through directional cross-linking with organic semiconductors at the liquid/air interface monitored simultaneously by in situ grazing incidence small angle X-ray scattering and grazing incidence X-ray diffraction. We determine the superlattice type, its symmetry and parameters, and the atomic orientation of NCs from the time-resolved scattering patterns. The superlattice contraction follows an exponential decay during ligand exchange, preserving always the two-dimensional square geometry. We attribute the contraction to the continuous replacement of oleic acid with smaller cobalt/copper 4,4′,4′′,4′′′-tetraaminophthalocyanine molecules. In these superlattices, the NCs are directed with a [100]AL axis perpendicular to the liquid surface for the whole assembly period. The kinetics and structural results provide a direct correlation between the superstructure and their atomic orientation on the liquid surface during self-assembly followed by ligand exchange.
η3-Allyl Coordination at Pb(II)
2018-12-17

Allylmagnesium chloride and methyl-propenyl-magnesium bromide were reacted with bulky substituted organolead and organotin halides (Ar*PbBr)2, (Ar′PbBr)2, (Ar*SnCl)2 (Ar* = 2,6-trip2C6H3-, trip = 2,4,6-triisopropylphenyl, Ar′ = 2,6-mes2C6H3-, mes = 2,4,6-trimethylphenyl). The allyl ligand coordinates in an η3-coordination mode at organoplumbylene fragments. In the solid state as well as in solution, η3-coordination was characterized by crystal structure analysis and Saunders' isotopic perturbation technique. For the plumbylene Ar*Pb(C3H5), a solid state 207Pb magic angle spinning (MAS) NMR spectrum could be obtained. The isotropic chemical shift is −435 ppm, and the magnitude of the 207Pb chemical shift tensor of 7000(500) ppm is among the greatest observed experimentally. The methylallyl ligand coordinated at a plumbylene fragment exhibits two short and one long Pb–C interaction. In reaction with aniline, the allyl ligand reacts as a leaving group to give amidoplumbylenes.
Frequency distributions of punctuation marks in English
2018-12-17

The analysis of punctuation in philology is mainly carried out with a view to better understand the meaning of the literature concerned. Punctuation is generally believed to play the role of ‘assisting the written language in indicating those elements of speech that cannot be conveniently set down on paper: chiefly the pause, pitch and stress in speech’ (Markwardt, 1942: 156). Most of us often ignore the importance of punctuation in writing systems and tend to believe that punctuation only depends on tradition and the personal styles of writers. In fact, punctuation marks may contribute significantly to the clarity of expression. Many linguists associate punctuation with intonation, but the truth is more complex than that – punctuation marks may affect orthography, morphology, syntactic relations, semantic information, and can even influence textual structure.
Association of HLA class I type with prevalence and outcome of patients with acute myeloid leukemia and mutated nucleophosmin
2018-12-17

Acute myeloid leukemia with mutated nucleophosmin (NPMc+ AML) forms a distinct AML subgroup with better prognosis which can potentially be associated with immune response against the mutated nucleophosmin (NPM). As the T-cell-mediated immunity involves antigen presentation on HLA class I molecules, we hypothesized that individuals with suitable HLA type could be less prone to develop NPMc+ AML. We compared HLA class I distribution in NPMc+ AML patient cohort (398 patients from 5 centers) with the HLA allele frequencies of the healthy population and found HLA-A*02, B*07, B*40 and C*07 underrepresented in the NPMc+ AML group. Presence of B*07 or C*07:01 antigen was associated with better survival in patients without concomitant FLT3 internal tandem duplication. Candidate NPM-derived immunopeptides were found for B*40 and B*07 using prediction software tools. Our findings suggest that a T-cell-mediated immune response could actually explain better prognosis of NPMc+ patients and provide a rationale for attempts to explore the importance of immunosuppressive mechanisms in this AML subgroup.
Loss of NFAT2 expression results in the acceleration of clonal evolution in chronic lymphocytic leukemia
2018-12-17

Abstract Chronic lymphocytic leukemia (CLL) can be defined as a clonal expansion of B cells with stereotypic BCRs. Somatic hypermutation of the BCR heavy chains (IGVH) defines a subgroup of patients with a better prognosis. In up to 10% of CLL cases, a transformation to an aggressive B cell lymphoma (Richter’s syndrome) with a dismal prognosis can be observed over time. NFAT proteins are transcription factors originally identified in T cells, which also play an important role in B cells. The TCL1 transgenic mouse is a well-accepted model of CLL. Upon B cell-specific deletion of NFAT2, TCL1 transgenic mice develop a disease resembling human Richter’s syndrome. Whereas TCL1 B cells exhibit tonic anergic BCR signaling characteristic of human CLL, loss of NFAT2 expression leads to readily activated BCRs indicating different BCR usage with altered downstream signaling. Here, we analyzed BCR usage in wild-type and TCL1 transgenic mice with and without NFAT2 deletion employing conventional molecular biology techniques and next-generation sequencing (NGS). We demonstrate that the loss of NFAT2 in CLL precipitates the selection of unmutated BCRs and the preferential usage of certain VDJ recombinations, which subsequently results in the accelerated development of oligoclonal disease.
Computing arbitrary Lagrangian Eulerian maps for evolving surfaces
2018-12-17

The good mesh quality of a discretized closed evolving surface is often compromised during time evolution. In recent years this phenomenon has been theoretically addressed in a few ways, one of them uses arbitrary Lagrangian Eulerian (ALE) maps. However, the numerical computation of such maps still remained an unsolved problem in the literature. An approach, using differential algebraic problems, is proposed here to numerically compute an arbitrary Lagrangian Eulerian map, which preserves the mesh properties over time. The ALE velocity is obtained by finding an equilibrium of a simple spring system, based on the connectivity of the nodes in the mesh. We also consider the algorithmic question of constructing acute surface meshes. We present various numerical experiments illustrating the good properties of the obtained meshes and the low computational cost of the proposed approach.
Theological War Theories
2018-12-17

This paperg ives an overview of how war theoriesi nC hristianity changed during the different periodso fw estern Christianity from the late antiquity to modern times.T he basic thesis is that, in contrast to the relationship between war and cult in ancient religions of the old Orient, Greece,and Rome,Christian war theories had not only one,but two functions to fulfill.On the one hand, the Christian religion had to cope with the inheritance of their traditional role models:priests and prophets had to support military force and to secure the victory by divine aid.Bellumiustum in this sense was the cult that pleased the Goddesses/God ande nsured their/his backing.On the other hand, bellum iustum in early Christian theology,and ever since,was aproblem of peace,restrictionof power,a nd ethically-based self control.After the conversion of Constantine to Christianity,Christian emperors, kings,and princes were inclined to emphasize the first target of Christian religion, while the theologians still had to interpret the moral restrictions on warfared evised by St Augustine,S tT homas Aquinas,F rancisco de Vitoria, and the philosophers of the Early modern international law.T hese competing expectations concerning the relationship of Christianity and warfare led to many ambiguities, all too oftenprecluding asubstantial contributionofChristian religiontoamore peaceful world.
How do compositional semantics and conceptual structures interact? A case study on German mental attitude adverbials
2018-12-17

This paper discusses German adverbials such as absichtlich ‘intentionally’ and freiwillig ‘voluntarily’ to gain deeper insights into the intricate interaction of compositional semantics and conceptual structures. The case study reveals the impact of conceptual knowledge on the adverbial’s interpretation and, moreover, how lexical semantics may curb the impact of conceptual knowledge. Based on the compositional interpretation of the adverbials, this paper argues against an underspecification analysis and proposes a coercion analysis spelled out in Asher’s (2011) Type Composition Logic.