116 research outputs found
LLMaAA: Making Large Language Models as Active Annotators
Prevalent supervised learning methods in natural language processing (NLP)
are notoriously data-hungry, which demand large amounts of high-quality
annotated data. In practice, acquiring such data is a costly endeavor.
Recently, the superior few-shot performance of large language models (LLMs) has
propelled the development of dataset generation, where the training data are
solely synthesized from LLMs. However, such an approach usually suffers from
low-quality issues, and requires orders of magnitude more labeled data to
achieve satisfactory performance. To fully exploit the potential of LLMs and
make use of massive unlabeled data, we propose LLMaAA, which takes LLMs as
annotators and puts them into an active learning loop to determine what to
annotate efficiently. To learn robustly with pseudo labels, we optimize both
the annotation and training processes: (1) we draw k-NN examples from a small
demonstration pool as in-context examples, and (2) we adopt the example
reweighting technique to assign training samples with learnable weights.
Compared with previous approaches, LLMaAA features both efficiency and
reliability. We conduct experiments and analysis on two classic NLP tasks,
named entity recognition and relation extraction. With LLMaAA, task-specific
models trained from LLM-generated labels can outperform the teacher within only
hundreds of annotated examples, which is much more cost-effective than other
baselines.Comment: Findings of EMNLP 2023 camera read
Two is Better Than One: Answering Complex Questions by Multiple Knowledge Sources with Generalized Links
Incorporating multiple knowledge sources is proven to be beneficial for
answering complex factoid questions. To utilize multiple knowledge bases (KB),
previous works merge all KBs into a single graph via entity alignment and
reduce the problem to question-answering (QA) over the fused KB. In reality,
various link relations between KBs might be adopted in QA over multi-KBs. In
addition to the identity between the alignable entities (i.e. full link),
unalignable entities expressing the different aspects or types of an abstract
concept may also be treated identical in a question (i.e. partial link). Hence,
the KB fusion in prior works fails to represent all types of links, restricting
their ability to comprehend multi-KBs for QA. In this work, we formulate the
novel Multi-KB-QA task that leverages the full and partial links among multiple
KBs to derive correct answers, a benchmark with diversified link and query
types is also constructed to efficiently evaluate Multi-KB-QA performance.
Finally, we propose a method for Multi-KB-QA that encodes all link relations in
the KB embedding to score and rank candidate answers. Experiments show that our
method markedly surpasses conventional KB-QA systems in Multi-KB-QA, justifying
the necessity of devising this task
4-(5-tert-Butyl-1,3-dithian-2-yl)-5-chloro-2-phenyl-1,3-oxazole
In the title molecule, C17H20ClNOS2, the phenyl and oxazole rings are nearly coplanar with an average deviation of 0.022 Å from the mean plane (M). The 1,3-dithiane ring adopts a chair conformation and is twisted in such a way that the C—CBu fragment lies in M (deviations are 0.031 and 0.010 Å, respectively, for the two C atoms)
The enhancement of electrochemical capacitance of biomass-carbon by pyrolysis of extracted nanofibers
Biomass-derived carbons have been extensively researched as electrode material for energy storage and conversion recently. However, most of the previous works convert crude biomass directly into carbon and the electrochemical capacitances for the resultant carbons are quite often underestimated as well as large variations in capacitances exist in literatures due to the complex nature of biomass, which practically hinder their applications. In this work, polysaccharide nanofibers were extracted from an inexpensive natural fungus using a hydrothermal method and were converted to porous carbon nanofibers (CNFs) by potassium hydroxide activation. The porous carbons were assembled into symmetric supercapacitors using both potassium hydroxide and an ionic liquid (IL) as electrolytes. Solid state nuclear magnetic resonance characterization showed that the micropores of the as-prepared carbons are accessible to the IL electrolyte when uncharged and thus high capacitance is expected. It is found in both electrolytes the electrochemical capacitances of CNFs are significantly higher than those of the porous carbon derived directly from the crude fungus. Furthermore, the CNFs delivered an extraordinary energy density of 92.3 Wh kg−1 in the IL electrolyte, making it a promising candidate for electrode materials for supercapacitors.<br/
Evolutionary dynamics of rabies viruses highlights the importance of China rabies transmission in Asia
AbstractRabies in Asia is emerging as a serious public health issue. To explore the possible origin, phylogenetic relationships, and evolutionary dynamics of Asian Rabies viruses (RABV), we examined 200 complete nucleoprotein (N) gene sequences from RABV isolates in the region. Phylogeny supported the classification of Asian RABVs into five distinct clusters in lyssavirus genotype 1. Our geospatial and temporal analyses demonstrated that China appears to be the prime source of Asian RABVs. Understanding of rabies transmission and associated human activities, such as dog translocation, can help rabies control and elimination in Asia through collaborative efforts or programs
Target Enzyme-Activated Two-Photon Fluorescent Probes:A Case Study of CYP3A4 Using a Two-Dimensional Design Strategy
The rapid development of fluorescent probes for monitoring target enzymes is still a great challenge owing to the lack of efficient ways to optimize a specific fluorophore. Herein, a practical two-dimensional strategy was designed for the development of an isoform-specific probe for CYP3A4, a key cytochrome P450 isoform responsible for the oxidation of most clinical drugs. In first dimension of the design strategy, a potential two-photon fluorescent substrate (NN) for CYP3A4 was effectively selected using ensemble-based virtual screening. In the second dimension, various substituent groups were introduced into NN to optimize the isoform-selectivity and reactivity. Finally, with ideal selectivity and sensitivity, NEN was successfully applied to the real-time detection of CYP3A4 in living cells and zebrafish. These findings suggested that our strategy is practical for developing an isoform-specific probe for a target enzyme.</p
Liquid gating elastomeric porous system with dynamically controllable gas/liquid transport
【Abstract】The development of membrane technology is central to fields ranging from resource harvesting to medicine, but the existing designs are unable to handle the complex sorting of multiphase substances required for many systems.
Especially, the dynamic multiphase transport and separation under a steady-state applied pressure have great
benefits for membrane science, but have not been realized at present. Moreover, the incorporation of precisely
dynamic control with avoidance of contamination of membranes remains elusive. We show a versatile strategy
for creating elastomeric microporous membrane-based systems that can finely control and dynamically modulate
the sorting of a wide range of gasesandliquids underasteady-stateapplied pressure,nearlyeliminate fouling,and
can be easily applied over many size scales, pressures, and environments. Experiments and theoretical calculation
demonstrate the stability of our system and the tunability of the critical pressure. Dynamic transport of gas and
liquid can be achieved through our gating interfacial design and the controllable pores’ deformation without
changing the applied pressure. Therefore, we believe that this system will bring new opportunities for many applications, such as gas-involved chemical reactions, fuel cells, multiphase separation, multiphase flow, multiphase microreactors, colloidal particle synthesis, and sizing nano/microparticles.This work was supported by the National Natural Science
Foundation of China (grant no. 21673197), the Young Overseas High-level Talents Introduction
Plan, the 111 Project (grant no. B16029).
研究工作得到国家自然科学基金委(项目批准号:21673197)和厦门大学校长基金(项目批准号:20720170050)等资助与支持
Fiber-based Ratiometric Optical Thermometry with Silicon-Vacancy in Microdiamonds
Fiber optic all-optical thermometry is a promising technology to track
temperature at a micro-scale while designing efficient and reliable
microelectronic devices and components. In this work, we demonstrate a novel
real-time ratiometric fiber optic thermometry technique based on
silicon-vacancy (SiV) diamond that shows the highest temperature resolution
(22.91 KHz^(-1/2) Wcm^(-2)) and spatial resolution (~7.5 um) among all-optical
fiber-based thermosensors reported to date. Instead of analyzing the spectral
features of temperature-dependent SiV signal, coming from SiV micro-diamond
fixed on the fiber tip, an alternative parallel detection method based on
filtering optics and photon counters is proposed to read out the sample
temperature in real-time. The signal collection efficiency of the fiber is also
investigated numerically with semi-analytic ray-optical analysis and then
compared with our experimental study. We finally demonstrate the performance of
the thermosensor by monitoring the temperature at distinct locations in a
lab-built graphite-based microheater device. Our work introduces a
reconfigurable method for temperature monitoring in microelectronic,
microfluidic devices, or biological environments and unlocks a new direction
for fiber-based all-optical thermometry research
Cryogenic Thermal Shock Effects on Optical Properties of Quantum Emitters in Hexagonal Boron Nitride
Solid-state quantum emitters are vital building blocks for quantum
information science and quantum technology. Among various types of solid-state
emitters discovered to date, color centers in hexagonal boron nitride have
garnered tremendous traction in recent years thanks to their environmental
robustness, high brightness and room-temperature operation. Most recently,
these quantum emitters have been employed for satellite-based quantum key
distribution. One of the most important requirements to qualify these emitters
for space-based applications is their optical stability against cryogenic
thermal shock. Such understanding has, however, remained elusive to date. Here,
we report on the effects caused by such thermal shock which induces random,
irreversible changes in the spectral characteristics of the quantum emitters.
By employing a combination of structural characterizations and density
functional calculations, we attribute the observed changes to lattice strains
caused by the cryogenic temperature shock. Our study shed light on the
stability of the quantum emitters under extreme conditions, similar to those
countered in outer space
Frequently Occurring Reconnection Jets from Sunspot Light Bridges
Solid evidence of magnetic reconnection is rarely reported within sunspots,
the darkest regions with the strongest magnetic fields and lowest temperatures
in the solar atmosphere. Using the world's largest solar telescope, the
1.6-meter Goode Solar Telescope, we detect prevalent reconnection through
frequently occurring fine-scale jets in the H line wings at light
bridges, the bright lanes that may divide the dark sunspot core into multiple
parts. Many jets have an inverted Y-shape, shown by models to be typical of
reconnection in a unipolar field environment. Simultaneous spectral imaging
data from the Interface Region Imaging Spectrograph show that the reconnection
drives bidirectional flows up to 200~km~s, and that the weakly ionized
plasma is heated by at least an order of magnitude up to 80,000 K. Such
highly dynamic reconnection jets and efficient heating should be properly
accounted for in future modeling efforts of sunspots. Our observations also
reveal that the surge-like activity previously reported above light bridges in
some chromospheric passbands such as the H core has two components:
the ever-present short surges likely to be related to the upward leakage of
magnetoacoustic waves from the photosphere, and the occasionally occurring long
and fast surges that are obviously caused by the intermittent reconnection
jets.Comment: ApJ, 8 figure
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