159 research outputs found
Exploring Effective Factors for Improving Visual In-Context Learning
The In-Context Learning (ICL) is to understand a new task via a few
demonstrations (aka. prompt) and predict new inputs without tuning the models.
While it has been widely studied in NLP, it is still a relatively new area of
research in computer vision. To reveal the factors influencing the performance
of visual in-context learning, this paper shows that prompt selection and
prompt fusion are two major factors that have a direct impact on the inference
performance of visual context learning. Prompt selection is the process of
identifying the most appropriate prompt or example to help the model understand
new tasks. This is important because providing the model with relevant prompts
can help it learn more effectively and efficiently. Prompt fusion involves
combining knowledge from different positions within the large-scale visual
model. By doing this, the model can leverage the diverse knowledge stored in
different parts of the model to improve its performance on new tasks. Based
these findings, we propose a simple framework prompt-SelF for visual in-context
learning. Specifically, we first use the pixel-level retrieval method to select
a suitable prompt, and then use different prompt fusion methods to activate all
the knowledge stored in the large-scale model, and finally ensemble the
prediction results obtained from different prompt fusion methods to obtain the
final prediction results. And we conduct extensive experiments on single-object
segmentation and detection tasks to demonstrate the effectiveness of
prompt-SelF. Remarkably, the prompt-SelF has outperformed OSLSM based
meta-learning in 1-shot segmentation for the first time. This indicated the
great potential of visual in-context learning. The source code and models will
be available at \url{https://github.com/syp2ysy/prompt-SelF}
Deletion of the meq gene significantly decreases immunosuppression in chickens caused by pathogenic marek's disease virus
<p>Abstract</p> <p>Background</p> <p>Marek's disease virus (MDV) causes an acute lymphoproliferative disease in chickens, resulting in immunosuppression, which is considered to be an integral aspect of the pathogenesis of Marek's disease (MD). A recent study showed that deletion of the Meq gene resulted in loss of transformation of T-cells in chickens and a Meq-null virus, rMd5ΔMeq, could provide protection superior to CVI988/Rispens.</p> <p>Results</p> <p>In the present study, to investigate whether the Meq-null virus could be a safe vaccine candidate, we constructed a Meq deletion strain, GX0101ΔMeq, by deleting both copies of the Meq gene from a pathogenic MDV, GX0101 strain, which was isolated in China. Pathogenesis experiments showed that the GX0101ΔMeq virus was fully attenuated in specific pathogen-free chickens because none of the infected chickens developed Marek's disease-associated lymphomas. The study also evaluated the effects of GX0101ΔMeq on the immune system in chickens after infection with GX0101ΔMeq virus. Immune system variables, including relative lymphoid organ weight, blood lymphocytes and antibody production following vaccination against AIV and NDV were used to assess the immune status of chickens. Experimental infection with GX0101ΔMeq showed that deletion of the Meq gene significantly decreased immunosuppression in chickens caused by pathogenic MDV.</p> <p>Conclusion</p> <p>These findings suggested that the Meq gene played an important role not only in tumor formation but also in inducing immunosuppressive effects in MDV-infected chickens.</p
Harmonic Analysis on Torque Ripple of Brushless DC Motor Based on Advanced Commutation Control
This paper investigates the relationship between current, back electromotive force (back-EMF), and torque for permanent-magnet brushless DC (PM BLDC) motors under advanced commutation control from the perspective of harmonics. Considering that the phase current is the influencing factor of both torque and torque ripple, this paper firstly analyzes the effects of advanced commutation on phase current and current harmonics. And then, based on the harmonics of the phase current and back-EMF, the torque harmonic expressions are deduced. The expressions reveal the relationship of harmonic order between the torque, phase current, and back-EMF and highlight the different contribution of individual torque harmonic to the total torque ripple. Finally, the proposed harmonic analysis method is verified by the experiments with different speed and load conditions
Refractive index sensitivity characteristics near the dispersion turning point of the multimode microfiber-based Mach–Zehnder interferometer
The turning point of the refractive index (RI) sensitivity based on the multimode microfiber (MMMF) in-line Mach–Zehnder interferometer (MZI) is observed. By tracking the resonant wavelength shift of the MZI generated between the HE11 and HE12 modes in the MMMF, the surrounding RI (SRI) could be detected. Theoretical analysis demonstrates that the RI sensitivity will reach ±∞ on either side of the turning point due to the group effective RI difference (퐺) approaching zero. Significantly, the positive sensitivity exists in a very wide fiber diameter range, while the negative sensitivity can be achieved in a narrow diameter range of only 0.3 μm. Meanwhile, the experimental sensitivities and variation trend at different diameters exhibit high consistency with the theoretical results. High RI sensitivity of 10777.8 nm/RIU (RI unit) at the fiber diameter of 4.6 μm and the RI around 1.3334 is realized. The discovery of the sensitivity turning points has great significance on trace detection due to the possibility of ultrahigh RI sensitivity
Bis[μ-bis(diphenylphosphino)methane-κ2 P:P′]bis[(4-toluenesulfonato-κO)silver(I)] monohydrate
The title complex, [Ag2(C7H7O3S)2(C25H22P2)2]·H2O, was obtained by the reaction of silver toluenesulfonate with diphenylphosphinomethane (dppm) in acetonitrile. There are two unique half-molecules of the complex in the asymmetric unit, together with one water molecule, which is disordered over two positions with site occupancy factors of 0.6 and 0.4. In each centrosymmetric neutral dimeric molecule, two Ag atoms are bridged by a pair of dppm ligands to give an eight-membered Ag2P4C2 ring with a distorted AgOP2 trigonal–planar environment. The Ag—Ag distances of 2.9215 (9) and 3.027 (1) Å indicate a direct bonding interaction
A combined laser-based ARPES and 2PPES study of Td-WTe
Laser-based angle-resolved photoemission spectroscopy (ARPES) and two-photon
photoemission spectroscopy (2PPES) are employed to study the valence electronic
structure of the Weyl semimetal candidate Td-WTe along two high symmetry
directions and for binding energies between -1 eV and 5 eV. The
experimental data show a good agreement with band structure calculations.
Polarization dependent measurements provide furthermore information on initial
and intermediate state symmetry properties with respect to the mirror plane of
the Td structure of WTe
Deletion of 1.8-kb mRNA of Marek's disease virus decreases its replication ability but not oncogenicity
<p>Abstract</p> <p>Background</p> <p>The 1.8-kb mRNA was reported as one of the oncogenesis-related genes of Marek's disease virus (MDV). In this study, the bacterial artificial chromosome (BAC) clone of a MDV field strain GX0101 was used as the platform to generate mutant MDV to examine the functional roles of 1.8-kb mRNA.</p> <p>Results</p> <p>Based on the BAC clone of GX0101, the 1.8-kb mRNA deletion mutant GX0101Δ(A+C) was constructed. The present experiments indicated that GX0101Δ(A+C) retained a low level of oncogenicity, and it showed a decreased replication capacity in vitro and in vivo when compared with its parent virus, GX0101. Further studies in vitro demonstrated that deletion of 1.8-kb mRNA significantly decreased the transcriptional activity of the bi-directional promoter between 1.8-kb mRNA and pp38 genes of MDV.</p> <p>Conclusion</p> <p>These results suggested that the 1.8-kb mRNA did not directly influence the oncogenesis but related to the replication ability of MDV.</p
Pressure-induced superconductivity in charge-density-wave compound LaTe2-xSbx (x=0 and 0.4)
Here, we have grown single crystals of LaTe2-xSbx (x=0 and 0.4) with
continuously adjustable CDW. High-pressure x-ray diffraction show LaTe2 does
not undergo phase transition and keep robust below 40 GPa. In-situ
high-pressure electrical measurements show LaTe2-xSbx undergo
semiconductor-metal-superconductivity transition at 4.6 and 2.5 GPa,
respectively. With the doping of Sb, the highest Tc increases from 4.6 to 6.5
K. Theoretical calculations reveal that the CDW has been completely suppressed
and the calculated Tc is about 2.97 K at 4.5 GPa, consistent with the measured
value. Then, the pressure-induced superconductivity in LaTe2-xSbx can be
explained in the framework of the BCS theory.Comment: 11 pages, 5 figure
Robust anomalous Hall effect in ferromagnetic metal under high pressure
Recently, the giant intrinsic anomalous Hall effect (AHE) has been observed
in the materials with kagome lattice. In this study, we systematically
investigate the influence of high pressure on the AHE in the ferromagnet
LiMn6Sn6 with clean Mn kagome lattice. Our in-situ high-pressure Raman
spectroscopy indicates that the crystal structure of LiMn6Sn6 maintains a
hexagonal phase under high pressures up to 8.51 GPa. The anomalous Hall
conductivity (AHC) {\sigma}xyA remains around 150 {\Omega}-1 cm-1, dominated by
the intrinsic mechanism. Combined with theoretical calculations, our results
indicate that the stable AHE under pressure in LiMn6Sn6 originates from the
robust electronic and magnetic structure.Comment: 11 pages 5 figure
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