115 research outputs found
CD-1 mice Show Individual Differences in Nicotine Preference in a Modified Two-Bottle Oral Self-Administration Model
Although both animal and human studies reveal significant contributions of genetics to smoking addiction, many human studies were underpowered or biased by potential confounding variables, and animal genetic studies are challenged by limited genetic variations and lack of convincing phenotypes. To address these concerns, we used non-sibling outbred CD-1 mice to evaluate individual differences in nicotine preference with a modified two-bottle oral self-administration model. Animals were first given free access to two bottles, one filled with nicotine dissolved in 2% saccharin and the other with saccharin only. Under this regular two-bottle choice condition, the majority of animals avoided the nicotine solution with limited individual differences. However, when we modified the model by introducing 4 days of exposure to 5% saccharin in the drinking water, the animals significantly increased nicotine consumption in the two-bottle choice test, with about 30% animals showing a nicotine preference. Nicotine preference after 5% saccharin treatment remained elevated throughout the 28 days of the experiment. Further, we found there existed striking individual differences in nicotine consumption after exposure to 5% saccharin, with a range of 0–100% of total liquid consumption. The enhanced individual differences and the ratio of nicotine consumption were observed at different concentrations of nicotine (10–80 μg/ml) and in both adolescents and adults. Further examination on the induction mechanism showed that the long-lasting nicotine preference was not correlated with nicotine consumption before the induction, 5% saccharin consumption, or weight gain during the induction. Although liquid consumption during the 4 days of 5% saccharin exposure was decreased by about 30%, comparable liquid restriction alone for 4 days did not induce nicotine preference. Together, this study showed a strong and stable nicotine preference in CD-1 mice, which was induced by a short-term high concentration of saccharin in the drinking water. Considering the nature and heterogeneity of CD-1 mice, the striking individual differences imply that genetics plays an important role in nicotine preference observed in these animals
SEGA: Structural Entropy Guided Anchor View for Graph Contrastive Learning
In contrastive learning, the choice of ``view'' controls the information that
the representation captures and influences the performance of the model.
However, leading graph contrastive learning methods generally produce views via
random corruption or learning, which could lead to the loss of essential
information and alteration of semantic information. An anchor view that
maintains the essential information of input graphs for contrastive learning
has been hardly investigated. In this paper, based on the theory of graph
information bottleneck, we deduce the definition of this anchor view; put
differently, \textit{the anchor view with essential information of input graph
is supposed to have the minimal structural uncertainty}. Furthermore, guided by
structural entropy, we implement the anchor view, termed \textbf{SEGA}, for
graph contrastive learning. We extensively validate the proposed anchor view on
various benchmarks regarding graph classification under unsupervised,
semi-supervised, and transfer learning and achieve significant performance
boosts compared to the state-of-the-art methods.Comment: ICML'2
Abiotic processes are insufficient for fertile island development: A ten‐year artificial shrub experiment in a desert grassland
The relative importance of biotic and abiotic processes in the development of “fertile islands” in dryland systems has rarely been investigated. Here we approached this question by using artificial shrubs, which exclude plant litter production and soil nutrient uptake, but retain the functions of trapping windblown material, funneling of stemflow, and differential rain splash. We conducted a vegetation manipulation study more than a decade ago in the desert grassland of southern New Mexico and subsequently revisited the site in 2012 and 2015. The results show that no notable soil mounds were observed under the artificial shrubs; however, soil texture under the artificial shrubs has gradually changed to resemble the patterns of soil particle-size distribution under natural shrubs. Our results highlight that with the exclusion of direct biotic additions, soils captured by shrub canopies are not necessarily fertile and thus do not themselves contribute to the development of fertile islands
A low frequency mechanical transmitter based on magnetoelectric heterostructures operated at their resonance frequency
Magneto-elasto-electric (ME) coupling heterostructures, consisting of piezoelectric layers bonded to magnetostrictive ones, provide for a new class of electromagnetic emitter materials on which a portable (area ~ 16 cm 2 ) very low frequency (VLF) transmitter technology could be developed. The proposed ME transmitter functions as follows: (a) a piezoelectric layer is first driven by alternating current AC electric voltage at its electromechanical resonance (EMR) frequency, (b) subsequently, this EMR excites the magnetostrictive layers, giving rise to magnetization change, (c) in turn, the magnetization oscillations result in oscillating magnetic fields. By Maxwell’s equations, a corresponding electric field, is also generated, leading to electromagnetic field propagation. Our hybrid piezoelectric-magnetostrictive transformer can take an input electric voltage that may include modulation-signal over a carrier frequency and transmit via oscillating magnetic field or flux change. The prototype measurements reveal a magnetic dipole like near field, demonstrating its transmission capabilities. Furthermore, the developed prototype showed a 10 4 times higher efficiency over a small-circular loop of the same area, exhibiting its superiority over the class of traditional small antennas
RbSn2(PO4)3, a NASICON-type phosphate
The title compound, rubidium ditin(IV) tris(phosphate), RbSn2(PO4)3, belongs to the NASICON-type family of phosphates and crystallizes in the space group R
. The structure is composed of PO4 tetrahedra (1 symmetry) and two slightly distorted SnO6 octahedra, both with 3. symmetry, which are interlinked through corner-sharing O atoms to form a 3
∞[Sn2(PO4)3]− framework. The Rb+ cations are located on threefold inversion axes in the voids of this framework and exhibit a coordination number of 12. The crystal studied was twinned by merohedry with a component ratio of 0.503:0.497
The Distribution and Accessibility of Urban Parks in Beijing, China: Implications of Social Equity
OWL: A Large Language Model for IT Operations
With the rapid development of IT operations, it has become increasingly
crucial to efficiently manage and analyze large volumes of data for practical
applications. The techniques of Natural Language Processing (NLP) have shown
remarkable capabilities for various tasks, including named entity recognition,
machine translation and dialogue systems. Recently, Large Language Models
(LLMs) have achieved significant improvements across various NLP downstream
tasks. However, there is a lack of specialized LLMs for IT operations. In this
paper, we introduce the OWL, a large language model trained on our collected
OWL-Instruct dataset with a wide range of IT-related information, where the
mixture-of-adapter strategy is proposed to improve the parameter-efficient
tuning across different domains or tasks. Furthermore, we evaluate the
performance of our OWL on the OWL-Bench established by us and open IT-related
benchmarks. OWL demonstrates superior performance results on IT tasks, which
outperforms existing models by significant margins. Moreover, we hope that the
findings of our work will provide more insights to revolutionize the techniques
of IT operations with specialized LLMs.Comment: 31 page
Recent Development of Nano-Materials Used in DNA Biosensors
As knowledge of the structure and function of nucleic acid molecules has increased, sequence-specific DNA detection has gained increased importance. DNA biosensors based on nucleic acid hybridization have been actively developed because of their specificity, speed, portability, and low cost. Recently, there has been considerable interest in using nano-materials for DNA biosensors. Because of their high surface-to-volume ratios and excellent biological compatibilities, nano-materials could be used to increase the amount of DNA immobilization; moreover, DNA bound to nano-materials can maintain its biological activity. Alternatively, signal amplification by labeling a targeted analyte with nano-materials has also been reported for DNA biosensors in many papers. This review summarizes the applications of various nano-materials for DNA biosensors during past five years. We found that nano-materials of small sizes were advantageous as substrates for DNA attachment or as labels for signal amplification; and use of two or more types of nano-materials in the biosensors could improve their overall quality and to overcome the deficiencies of the individual nano-components. Most current DNA biosensors require the use of polymerase chain reaction (PCR) in their protocols. However, further development of nano-materials with smaller size and/or with improved biological and chemical properties would substantially enhance the accuracy, selectivity and sensitivity of DNA biosensors. Thus, DNA biosensors without PCR amplification may become a reality in the foreseeable future
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