166 research outputs found
Impact of cadmium stress on soil virus reproduction and the persistence of viruses under abiotic conditions
Soil viruses are ubiquitous and greatly impact the structure and function of soil microbial communities, with their effects modulated by various environmental factors. This study investigates the inactivation of naturally occurring soil viruses in sterilized soil, as well as the effects of cadmium (Cd) exposure and carbon (C) and nitrogen (N) nutrient availability on the population dynamics of virus-host communities in agricultural soil.
Lab-scale slurry and unsaturated experiments were performed to examine virus inactivation in the absence of host bacteria in sterilized soil. In slurry experiments, virus abundance declined by over 90% after 10 days of incubation. The addition of bacteria mitigated this decrease, though a declining trend persisted. In unsaturated experiments, virus abundance initially decreased from 1E+09 to 4.49E+08 after 10 days, followed by a substantial increase to 6.76E+09 on day 13 upon bacteria reintroduction. Further experiments assessed the impact of Cd exposure and nutrient availability on soil virus dynamics, demonstrating that both Cd and incubation time significantly influenced virus diversity and abundance, with Cd inducing prophage activation.
This research highlights the complex relationships within soil microbial communities and their implications for agricultural ecosystems, focusing on the survival of fresh soil viruses in the absence of host bacteria and the impact of heavy metal exposure on virus dynamics. Integrating viral activity into the overall function of soil food webs can improve our understanding of soil health, optimize soil management practices, and potentially lead to novel virus-based applications in crop health
Periodic solutions of the Lp-Minkowski problem with indefinite weight
We provide a new sufficient condition for the existence of a periodic solution of the singular differential equation
u '' + u = h(t)/u(rho),
which is associated with the planar L-p-Minkowski problem. A similar result is valid for the conformal version of the problem.National Natural Science Foundation of China (NSFC) 11501170Technological innovation talents in universities and colleges in Henan Province 21HASTIT02
Attentive Aspect Modeling for Review-aware Recommendation
In recent years, many studies extract aspects from user reviews and integrate
them with ratings for improving the recommendation performance. The common
aspects mentioned in a user's reviews and a product's reviews indicate indirect
connections between the user and product. However, these aspect-based methods
suffer from two problems. First, the common aspects are usually very sparse,
which is caused by the sparsity of user-product interactions and the diversity
of individual users' vocabularies. Second, a user's interests on aspects could
be different with respect to different products, which are usually assumed to
be static in existing methods. In this paper, we propose an Attentive
Aspect-based Recommendation Model (AARM) to tackle these challenges. For the
first problem, to enrich the aspect connections between user and product,
besides common aspects, AARM also models the interactions between synonymous
and similar aspects. For the second problem, a neural attention network which
simultaneously considers user, product and aspect information is constructed to
capture a user's attention towards aspects when examining different products.
Extensive quantitative and qualitative experiments show that AARM can
effectively alleviate the two aforementioned problems and significantly
outperforms several state-of-the-art recommendation methods on top-N
recommendation task.Comment: Camera-ready manuscript for TOI
Assessment of Reclamation Treatments of Abandoned Farmland in an Arid Region of China
Reclamation of abandoned farmland is crucial to a sustainable agriculture in arid regions.
This study aims to evaluate the impact of different reclamation treatments on abandoned salinized
farmland. We investigated four artificial reclamation treatments, continuous cotton (CC), continuous
alfalfa (CA), tree-wheat intercropping (TW) and trees (TS), which were conducted in 2011–2012
in the Manasi River Basin of Xinjiang Province, China. Soil nutrient, microorganism and enzyme
activity were examined in comparison with natural succession (CK) in an integrated analysis on
soil fertility improvement and soil salinization control with these reclamations. Results indicate that
the four artificial reclamation treatments are more effective approaches than natural restoration to
reclaim abandoned farmland. TW and CA significantly increased soil nutrient content compared to
CK. CC reduced soil salinity to the lowest level among all treatments. TW significantly enhanced
soil enzyme activity. All four artificial reclamations increased soil microbial populations and soil
microbial biomass carbon. TW and CA had the greatest overall optimal effects among the four
treatments in terms of the ecological outcomes. If both economic benefits and ecological effects are
considered, TW would be the best reclamation mode. The findings from this study will assist in
selecting a feasible method for reclamation of abandoned farmland for sustainable agriculture in
arid regions.This research was supported by the Special Fund for Agro-scientific Research in the Public
Interest (201503120); Science and Technology Research and Achievement Transformation Project of The Xinjiang
Production and Construction Crops (2016AD022); and the National Key Technology Research and Development
Program of the Ministry of Science and Technology of China (2014BAC14B03)
Experimental test of the Crooks fluctuation theorem in a single nuclear spin
We experimentally test the Crooks fluctuation theorem in a quantum spin
system. Our results show that the Crooks fluctuation theorem is valid for
different speeds of the nonequilibrium processes and under various effective
temperatures. Work is not an observable in quantum systems, which makes tests
of quantum thermodynamic theorems challenging. In this work, we developed
high-fidelity single-shot readouts of a single nuclear spin in diamond and
implemented the two-point work measurement protocol, enabling a direct
experimental test of the Crooks fluctuation theorem. Our results provide a
quantum insight into fluctuations and the methods we developed can be utilized
to study other quantum thermodynamic theorems
Numerical simulation of factors affecting flow characteristics of double-circular-arc gear pump
Objective: Analyzed the influencing factors of the internal flow field pulsation characteristics of the new double circular arc gear pump, and adopt reasonable parameters to improve the output efficiency of the gear pump. Methods: The two-dimensional flow field simulation model of the gear pump was established, and the computational fluid dynamics software Fluent was used for simulation analysis to study the influence of different tip clearance, different gear eccentricity, load and speed on the instantaneous flow, flow pulsation and flow field characteristics of the oil outlet of the gear pump. Results: As the tooth tip clearance increased, the outlet flow rate of the gear pump gradually decreased. When the tooth tip clearance was 0.09 mm, the minimum pulsation coefficient of the outlet flow rate was 0.135, which was the optimal tooth tip clearance for the gear pump under this structural parameter. Due to the influence of load pressure and rotational speed, the central axis of the gear pump deviates. As the eccentricity of the central axis of the gear pump rotor increased, the outlet flow rate of the gear pump gradually increased. When the eccentricity was 0.05 mm, the outlet flow rate of the gear pump increased by 5.09% compared to without central deviation, improving the flow output. Conclusion: The main influencing factors on the flow characteristics of gear pumps are rotor speed and tooth tip clearance, and the influence of center deviation is relatively small
SurrogatePrompt: Bypassing the Safety Filter of Text-To-Image Models via Substitution
Advanced text-to-image models such as DALL-E 2 and Midjourney possess the
capacity to generate highly realistic images, raising significant concerns
regarding the potential proliferation of unsafe content. This includes adult,
violent, or deceptive imagery of political figures. Despite claims of rigorous
safety mechanisms implemented in these models to restrict the generation of
not-safe-for-work (NSFW) content, we successfully devise and exhibit the first
prompt attacks on Midjourney, resulting in the production of abundant
photorealistic NSFW images. We reveal the fundamental principles of such prompt
attacks and suggest strategically substituting high-risk sections within a
suspect prompt to evade closed-source safety measures. Our novel framework,
SurrogatePrompt, systematically generates attack prompts, utilizing large
language models, image-to-text, and image-to-image modules to automate attack
prompt creation at scale. Evaluation results disclose an 88% success rate in
bypassing Midjourney's proprietary safety filter with our attack prompts,
leading to the generation of counterfeit images depicting political figures in
violent scenarios. Both subjective and objective assessments validate that the
images generated from our attack prompts present considerable safety hazards.Comment: 14 pages, 11 figure
Experimental test of the Jarzynski equality in a single spin-1 system using high-fidelity single-shot readouts
The Jarzynski equality (JE), which connects the equilibrium free energy with
non-equilibrium work statistics, plays a crucial role in quantum
thermodynamics. Although practical quantum systems are usually multi-level
systems, most tests of the JE were executed in two-level systems. A rigorous
test of the JE by directly measuring the work distribution of a physical
process in a high-dimensional quantum system remains elusive. Here, we report
an experimental test of the JE in a single spin-1 system. We realized
nondemolition projective measurement of this three-level system via cascading
high-fidelity single-shot readouts and directly measured the work distribution
utilizing the two-point measurement protocol. The validity of the JE was
verified from the non-adiabatic to adiabatic zone and under different effective
temperatures. Our work puts the JE on a solid experimental foundation and makes
the NV center system a mature toolbox to perform advanced experiments of
stochastic quantum thermodynamics
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