6,263 research outputs found
[μ-1,1′-(Butane-1,4-diÂyl)di-1H-benzÂimidazole-κ2 N 3:N 3′]bisÂ{[N,N′-bis(carÂboxyÂmethÂyl)ethylÂenediamine-N,N′-diÂacetato-κ5 O,O′,O′′,N,N′]mercury(II)} methanol disolvate
The binuclear title complex, [Hg2(C10H14N2O8)2(C18H18N4)]·2CH3OH, lies on an inversion center with the unique HgII ion coordinated in a disorted octaÂhedral environment with one Hg—N bond significantly shorter than the other two. In the crystal structure, interÂmolecular O—H⋯O hydrogen bonds link complex and solvent molÂecules into a three-dimensional network
Ba-enhanced dwarf and subgiant stars in the LAMOST Galactic surveys
Ba-enhanced stars are interesting probes of stellar astrophysics and Galactic
formation history. In this work, we investigate the chemistry and kinematics
for a large sample of Ba-enhanced ([Ba/Fe]1.0) dwarf and subgiant stars with
\,K from LAMOST. We find that both stellar internal
evolution process and external mass exchange due to binary evolution are
responsible for the origins of the Ba-enhancement of our sample stars. About
one third of them exhibit C and N enhancement and ultraviolet brightness
excess, indicating they are products of binary evolution. The remaining
Ba-enhanced stars with normal C and N abundances are mostly warm stars with
\,K. They are likely consequences of stellar internal
elemental transport processes, but they show very different elemental patterns
to the hotter Am/Fm stars. Our results reveal a substantially lack of
high-[/Fe] Ba-enhanced stars in the [Fe/H]--[/Fe] plane, which
we dub as a {\em high- desert}. We suggest it is due to a lower
efficiency for producing Ba-enhanced stars by low-mass AGB progenitors in
binary systems. Our results call for detailed modellings for these Ba-enhanced
stellar peculiars, in the context of both stellar internal elemental transport
and external mass accretion.Comment: 20 pages, 17 figures. Accepted for publication in Ap
The physics case for a neutrino lepton collider in light of the CDF W mass measurement
We propose a neutrino lepton collider where the neutrino beam is generated
from TeV scale muon decays. Such a device would allow for a precise measurement
of the W mass based on single W production: nu l to W. Although it is
challenging to achieve high instantaneous luminosity with such a collider, we
find that a total luminosity of 0.1/fb can already yield competitive physics
results. In addition to a W mass measurement, a rich variety of physics goals
could be achieved with such a collider, including W boson precision
measurements, heavy leptophilic gauge boson searches, and anomalous Znunu
coupling searches. A neutrino lepton collider is both a novel idea in itself,
and may also be a useful intermediate step, with less muon cooling required,
towards the muon-muon collider already being pursued by the energy frontier
community. A neutrino neutrino or neutrino proton collider may also be
interesting future options for the high energy frontier.Comment: 4 pages, 5 plots, accepted version by IJMP
Prepreg and Core Dielectric Permittivity (ϵr) Extraction for Fabricated Striplines\u27 Far-End Crosstalk Modeling
As the data rate and density of digital high-speed systems are getting higher, far-end crosstalk (FEXT) noise becomes one of the major issues that limit signal integrity performance. It was commonly believed that FEXT would be eliminated for strip lines routed in a homogeneous dielectric, but in reality, FEXT can always be measured in strip lines on the fabricated printed circuit boards. A slightly different dielectric permittivity (ϵr) of prepreg and core may be one of the major contributors to the FEXT. This article is focusing on providing a practical FEXT modeling methodology for strip lines by introducing an approach to extract ϵr of prepreg and core. Using the known cross-sectional geometry and measured S-parameters of the coupled strip line, the capacitance components in prepreg and core are separated using a two-dimensional solver, and the ϵr of prepreg and core is determined. A more comprehensive FEXT modeling approach is proposed by applying extracted inhomogeneous dielectric material information
Association between decreased serum TBIL concentration and immediate memory impairment in schizophrenia patients
© 2019, The Author(s). Cognitive impairment is a core feature of schizophrenia (SCH). In addition to the toxic effect of Bilirubin (BIL), it has antioxidant properties that were associated with the psychopathology and cognitive impairment of psychiatric disorders. The aim of this study was to examine the correlation of serum total BIL (TBIL) concentration with cognitive impairment in SCH patients. We recruited 34 SCH patients and 119 healthy controls (HCs) in this case-control design. Cognition was assessed using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Serum TBIL concentration was measured using the immunoturbidimetric method. Serum TBIL concentration was significantly decreased in SCH patients compared to HCs after adjusting for age, gender, and education. Serum TBIL concentration in SCH patients was also positively correlated with the RBANS immediate memory score. Further stepwise multiple regression analysis confirmed the positive association between serum TBIL concentration and immediate memory score in SCH patients. Our findings supported that the decline in serum TBIL concentration was associated with the immediate memory impairment and psychopathology of SCH
Exposures to particulate matters and childhood sleep disorders—A large study in three provinces in China
Objectives: Evidence on the link between long-term ambient particulate matter (PM) exposures and childhood sleep disorders were scarce. We examined the associations between long-term exposures to PM2.5 and PM1 (PM with an aerodynamic equivalent diameter <2.5 μm and <1 μm, respectively) with sleep disorders in children. Methods: We performed a population-based cross-sectional survey in 177,263 children aged 6 to 18 years in 14 Chinese cities during 2012–2018. A satellite-based spatiotemporal model was employed to estimate four-year annual average PM2.5 and PM1 exposures at residential and school addresses. Parents or guardians completed a checklist using the Sleep Disturbance Scale for Children. We estimated the associations using generalized linear mixed models with adjustment for characteristics of children, parents, and indoor environments. Results: Long-term PM2.5 and PM1 exposures were positively associated with odds of sleep disorders for almost all domains. For example, increments in PM2.5 and PM1 per 10 μg/m3 were associated with odds ratios of global sleep disorder of 1.24 (95 % confidence interval [CI]: 1.14, 1.35) and 1.31 (95 %CI: 1.18, 1.46), respectively. Similar results were observed for subtypes of sleep disorder. These associations were heterogeneous regionally, with stronger associations among children residing in southeast region than in northeast and northwest regions. Moreover, larger estimates of PM1 were found than that of PM2.5 in southeast region. Conclusion: Long-term PM2.5 and PM1 exposures are independently associated with higher risks of childhood sleep disorders, and these associations vary by geographical region
Superconductivity emerged from density-wave order in a kagome bad metal
Unconventional superconductivity (USC) in a highly correlated kagome system
has been theoretically proposed for years, yet the experimental realization is
hard to achieve. The recently discovered vanadium-based kagome materials, which
exhibit both superconductivity and charge density wave (CDW) orders, are
nonmagnetic and weakly correlated, thus unlikely host USC as theories proposed.
Here we report the discovery of a chromium-based kagome bad metal,
CsCrSb, which is contrastingly characterised by significant electron
correlations and frustrated magnetism. Successive phase transitions at 54
K with stripe-like structural modulations are observed, probably
associated with CDW and antiferromagnetic spin-density-wave (SDW) orderings.
Under moderately high pressures of 4-8 GPa, these density-wave orders are
suppressed and, remarkably, superconductivity emerges with a maximum
of 6.4 K. A quantum critical point at 4
GPa is revealed, by which non-Fermi-liquid behaviours show up, reminiscent of
USC in iron-based superconductors. The electronic structure calculations
indicate that the electron filling is close to the characteristic flat bands of
the kagome lattice. Our work offers an unprecedented platform for investigating
the mechanism of USC in a correlated kagome system.Comment: 26 pages, 10 figure
Neoproterozoic to Paleozoic long-lived accretionary orogeny in the northern Tarim Craton
The Tarim Craton, located in the center of Asia, was involved in the assembly and breakup of the Rodinia supercontinent during the Neoproterozoic and the subduction-accretion of the Central Asian Orogenic Belt (CAOB) during the Paleozoic. However, its tectonic evolution during these events is controversial, and a link between the Neoproterozoic and Paleozoic tectonic processes is missing. Here we present zircon U-Pb ages, Hf isotopes, and whole-rock geochemical data for the extensive granitoids in the western Kuruktag area, northeastern Tarim Craton. Three distinct periods of granitoid magmatism are evident: circa 830–820 Ma, 660–630 Ma, and 420–400 Ma. The magma sources, melting conditions (pressure, temperature, and water availability), and tectonic settings of various granitoids from each period are determined. Based on our results and the geological, geochronological, geochemical, and isotopic data from adjacent areas, a long-lived accretionary orogenic model is proposed. This model involves an early phase (circa 950–780 Ma) of southward advancing accretion from the Tianshan to northern Tarim and a late phase (circa 780–600 Ma) of northward retreating accretion, followed by back-arc opening and subsequent bidirectional subduction (circa 460–400 Ma) of a composite back-arc basin (i.e., the South Tianshan Ocean). Our model highlights a long-lived accretionary history of the southwestern CAOB, which may have initiated as part of the circum-Rodinia subduction zone and was comparable with events occurring at the southern margin of the Siberian Craton, thus challenging the traditional southward migrating accretionary models for the CAOB
Artificial intelligence : A powerful paradigm for scientific research
Y Artificial intelligence (AI) coupled with promising machine learning (ML) techniques well known from computer science is broadly affecting many aspects of various fields including science and technology, industry, and even our day-to-day life. The ML techniques have been developed to analyze high-throughput data with a view to obtaining useful insights, categorizing, predicting, and making evidence-based decisions in novel ways, which will promote the growth of novel applications and fuel the sustainable booming of AI. This paper undertakes a comprehensive survey on the development and application of AI in different aspects of fundamental sciences, including information science, mathematics, medical science, materials science, geoscience, life science, physics, and chemistry. The challenges that each discipline of science meets, and the potentials of AI techniques to handle these challenges, are discussed in detail. Moreover, we shed light on new research trends entailing the integration of AI into each scientific discipline. The aim of this paper is to provide a broad research guideline on fundamental sciences with potential infusion of AI, to help motivate researchers to deeply understand the state-of-the-art applications of AI-based fundamental sciences, and thereby to help promote the continuous development of these fundamental sciences.Peer reviewe
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