428 research outputs found
Vortex patterns and the critical rotational frequency in rotating dipolar Bose-Einstein condensates
Based on the two-dimensional mean-field equations for pancake-shaped dipolar
Bose-Einstein condensates in a rotating frame with both attractive and
repulsive dipole-dipole interaction (DDI) as well as arbitrary polarization
angle, we study the profiles of the single vortex state and show how the
critical rotational frequency change with the s-wave contact interaction
strengths, DDI strengths and the polarization angles. In addition, we find
numerically that at the `magic angle' , the
critical rotational frequency is almost independent of the DDI strength. By
numerically solving the dipolar GPE at high rotational speed, we identify
different patterns of vortex lattices which strongly depend on the polarization
direction. As a result, we undergo a study of vortex lattice structures for the
whole regime of polarization direction and find evidence that the vortex
lattice orientation tends to be aligned with the direction of the dipoles
Olfaction in Host Plant Selection of the Soybean Aphid Aphis glycines
Results from a behavioral study using a four-armed olfactometer (Vet et al, 1983) showed that alate and apterous virginopara of Aphis glycines were clearly attracted or arrested by volatiles from Glycine max, its secondary host plant, and Rhamnus davurica, its primary host plant. The attractiveness of G. max was greater than that of R. davurica. Chemical analysis indicated that there is some difference in the volatile profiles between these two plant species. The volatiles from two nonhost plant species Gossypium hirsutrm and Cucumis sativa, which are the most suitable host plants of another aphid A. gossypii closely related to A. glycines, were found to be neutral. However, the odors of Luffa cylindrical and Cucurbita pepo significantly repelled the alate virginopara of A. glycines. Thus, the olfactory response of A. glycines to these host and nonhost plants implies the evolutionary transition of A. glycines in host plant specificity. Blending the odors from nonhost plants Gossypium hirsutum, Luffa cylindrical and Cucurbita pepo with the attractive odor of host plant G. max blocked the attractiveness of the latter to the alate virginopara of A. glycines. It thus appeared that attractiveness of host plant to aphids can be disrupted by the presence of nonhost plant volatiles which have presumably masked the host plant odor, and the lack of attractiveness of the blended odors is caused by the change in volatile profile.Originating text in Chinese.Citation: Du, Yongjun, Yan, Fushun, Han, Xinli, Zhang, Guangxue. (1994). Olfaction in Host Plant Selection of the Soybean Aphid Aphis glycines. Kun chong xue bao. Acta entomologica Sinica, 37(4), 385-392
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Meta-analysis of preclinical studies of mesenchymal stromal cells to treat rheumatoid arthritis.
BackgroundThis study aims to evaluate the quality of preclinical data, determine the effect sizes, and identify experimental measures that inform efficacy using mesenchymal stromal (or stem) cells (MSC) therapy in animal models of rheumatoid arthritis (RA).MethodsLiterature searches were performed on MSC preclinical studies to treat RA. MSC treatment effect sizes were determined by the most commonly used outcome measures, including paw thickness, clinical score, and histological score.FindingsA total of 48 studies and 94 treatment arms were included, among which 42 studies and 79 treatment arms reported that MSC improved outcomes. The effect sizes of RA treatments using MSC, when compared to the controls, were: paw thickness was ameliorated by 53.6% (95% confidence interval (CI): 26.7% -80.4%), histological score was decreased by 44.9% (95% CI: 33.3% -56.6%), and clinical score was decreased by 29.9% (95% CI: 16.7% -43.0%). Specifically, our results indicated that human umbilical cord derived MSC led to large improvements of the clinical score (-42.1%) and histological score (-51.4%).InterpretationTo the best of our knowledge, this meta-analysis is to quantitatively answer whether MSC represent a robust RA treatment in animal models. It suggests that in preclinical studies, MSC have consistently exhibited therapeutic benefits. The findings demonstrate a need for considering variations in different animal models and treatment protocols in future studies using MSC to treat RA in humans to maximise the therapeutic gains in the era of precision medicine.FundsNIH [1DP2CA195763], Baylx Inc.: BI-206512, NINDS/NIH Training Grant [Award# NS082174]
CLIP-KD: An Empirical Study of Distilling CLIP Models
CLIP has become a promising language-supervised visual pre-training framework
and achieves excellent performance over a wide range of tasks. This paper aims
to distill small CLIP models supervised by a large teacher CLIP model. We
propose several distillation strategies, including relation, feature, gradient
and contrastive paradigm, to examine the impact on CLIP distillation. We show
that the simplest feature mimicry with MSE loss performs best. Moreover,
interactive contrastive learning and relation-based distillation are also
critical in performance improvement. We apply the unified method to distill
several student networks trained on 15 million (image, text) pairs.
Distillation improves the student CLIP models consistently over zero-shot
ImageNet classification and cross-modal retrieval benchmarks. We hope our
empirical study will become an important baseline for future CLIP distillation
research. The code is available at \url{https://github.com/winycg/CLIP-KD}
Time to Progress: the Impact of Temporal Ownership on Time Perception
Time is often linguistically portrayed either in a narrative or possessive framing. Building on this tendency, the authors demonstrate that communicating time in possession framing increases perceived ownership and feelings of responsibility towards making use of time. The heightened responsibility leads consumers to minimize time loss, but maximize time investment
Exploring Structured Semantic Prior for Multi Label Recognition with Incomplete Labels
Multi-label recognition (MLR) with incomplete labels is very challenging.
Recent works strive to explore the image-to-label correspondence in the
vision-language model, \ie, CLIP, to compensate for insufficient annotations.
In spite of promising performance, they generally overlook the valuable prior
about the label-to-label correspondence. In this paper, we advocate remedying
the deficiency of label supervision for the MLR with incomplete labels by
deriving a structured semantic prior about the label-to-label correspondence
via a semantic prior prompter. We then present a novel Semantic Correspondence
Prompt Network (SCPNet), which can thoroughly explore the structured semantic
prior. A Prior-Enhanced Self-Supervised Learning method is further introduced
to enhance the use of the prior. Comprehensive experiments and analyses on
several widely used benchmark datasets show that our method significantly
outperforms existing methods on all datasets, well demonstrating the
effectiveness and the superiority of our method. Our code will be available at
https://github.com/jameslahm/SCPNet.Comment: Accepted by IEEE/CVF Conference on Computer Vision and Pattern
Recognition (CVPR) 202
Experimental study on atomization characteristics of two common spiral channel pressure nozzles
Spiral channel pressure nozzles are commonly used pressure nozzles in practical workplaces. In this paper, two kinds of spiral channel type pressure nozzles, namely, spiral hole type and spiral non-porous type, the atomization characteristics and dust reduction efficiency under different spray pressures are discussed and compared. Based on the experimental method, based on the self-designed spray dust-reducing roadway experimental platform, the macro-atomization characteristics of the two nozzles, namely the flow rate, the atomization angle, the range, and the droplet size, were measured. The following conclusions were drawn: (1) The flow rates of both nozzles increase with increasing spray pressure, and the flow coefficient of the spiral non-porous nozzle is small. (2) The change of the atomization angle of the two nozzles first increases and then decreases with the increase of the spray pressure, and the atomization angle of the spiral non-porous nozzle is larger. At the same time, the range of the two nozzles gradually increases as the spray pressure increases, and the range of the spiral perforated nozzle is always larger than that of the spiral non-porous nozzle. (3) When the spray pressure is gradually increased, the droplet size of the two nozzles selected in the experiment is gradually reduced, and the droplet size of the spiral perforated nozzle is always larger than that of the spiral non-porous nozzle before 5 MPa, and then gradually Become smaller. The main reason why the droplet size decreases with the increase of the spray pressure is that the increase of the spray pressure leads to an increase in the spray speed of the water droplets, so that the water droplets are completely split when they are ejected from the nozzle, resulting in a smaller droplet size. In summary, when the spray pressure required in the actual working environment is low, the use of a spiral non-porous nozzle is more conducive to dust reduction
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Distributed secure storage scheme based on sharding blockchain
Distributed storage can store data in multiple devices or servers to improve data security. However, in today’s explosive growth of network data, traditional distributed storage scheme is faced with some severe challenges such as insufficient performance, data tampering, and data lose. A distributed storage scheme based on blockchain has been proposed to improve security and efficiency of traditional distributed storage. Under this scheme, the following improvements have been made in this paper. This paper first analyzes the problems faced by distributed storage. Then proposed to build a new distributed storage blockchain scheme with sharding blockchain. The proposed scheme realizes the partitioning of the network and nodes by means of blockchain sharding technology, which can improve the efficiency of data verification between nodes. In addition, this paper uses polynomial commitment to construct a new verifiable secret share scheme called PolyVSS. This new scheme is one of the foundations for building our improved distributed storage blockchain scheme. Compared with the previous scheme, our new scheme does not require a trusted third party and has some new features such as homomorphic and batch opening. The security of VSS can be further improved. Experimental comparisons show that the proposed scheme significantly reduces storage and communication costs
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