Turing instability in a diffusive predator-prey model with multiple Allee effect and herd behavior

Diffusion-driven instability and bifurcation analysis are studied in a predator-prey model with herd behavior and quadratic mortality by incorporating multiple Allee effect into prey species. The existence and stability of the equilibria of the system are studied. And bifurcation behaviors of the system without diffusion are shown. The sufficient and necessary conditions for Turing instability occurring are obtained. And the stability and the direction of Hopf and steady state bifurcations are explored by using the normal form method. Furthermore, some numerical simulations are presented to support our theoretical analysis. We found that too large diffusion rate of prey prevents Turing instability from emerging. Finally, we summarize our findings in the conclusion

MVDream: Multi-view Diffusion for 3D Generation

We propose MVDream, a multi-view diffusion model that is able to generate geometrically consistent multi-view images from a given text prompt. By leveraging image diffusion models pre-trained on large-scale web datasets and a multi-view dataset rendered from 3D assets, the resulting multi-view diffusion model can achieve both the generalizability of 2D diffusion and the consistency of 3D data. Such a model can thus be applied as a multi-view prior for 3D generation via Score Distillation Sampling, where it greatly improves the stability of existing 2D-lifting methods by solving the 3D consistency problem. Finally, we show that the multi-view diffusion model can also be fine-tuned under a few shot setting for personalized 3D generation, i.e. DreamBooth3D application, where the consistency can be maintained after learning the subject identity.Comment: Our project page is https://MV-Dream.github.i

Spatiotemporal Distribution and Evolution Characteristics of Water Traffic Accidents in Asia since the 21st Century

As an important mode of transportation for the global trade, waterborne transportation has become a priority option for import and export trade due to its large load capacity and relatively low cost. Meanwhile, shipping safety has been highly valued. By collecting technological water traffic accident data from the EM-DAT database, the spatiotemporal distribution and evolution characteristics were investigated in Asia since 2000. The methods of gravity center and standard deviation ellipse analysis were utilized to determine the spatial and data-related characteristics of water traffic accidents. Temporally, the results indicated that accidents occurred most frequently during the seasons of autumn and winter, leading to a significant number of casualties. Spatially, both South-eastern Asia and Southern Asia emerged as regions with a high frequency of water traffic accidents, particularly along the borders of Singapore, Malaysia, Indonesia, and the Bay of Bengal region. In addition, the Daniel trend test and R/S analysis were conducted to demonstrate the evolution trend of accidents across various regions and seasons. The present study provides guidance for improving marine shipping safety, emergency resource management, and relevant policy formulation

Annual Migration of Cabbage Moth, <i>Mamestra brassicae</i> L. (Lepidoptera: Noctuidae), over the Sea in Northern China

<div><p>The cabbage moth, <i>Mamestra brassicae</i> L. (Lepidoptera: Noctuidae), is a serious pest of vegetable crops throughout the world. In order to determine whether or not <i>M</i>. <i>brassicae</i> is a migrant, and if yes, what is the pattern of <i>M</i>. <i>brassicae</i> seasonal migration, a long-term study on <i>M</i>. <i>brassicae</i> from April to October in 2003–2014 was carried out by means of a searchlight trap on a small island located in the center of the Bohai Strait. The results show that a large number of <i>M</i>. <i>brassicae</i> were trapped every year on the island, which indicates that <i>M</i>. <i>brassicae</i> is a migrant and migrated at least 40–60 km across the Bohai Strait. The mean migration period of <i>M</i>. <i>brassicae</i> over the sea within one year is 151 ± 8 d in 2003–2014, with the shortest time span 78 d in 2003 and the longest 189 d in 2014, respectively. The number of <i>M</i>. <i>brassicae</i> captured, however, varies considerably between months or years. The majority of captures were female, with different levels of ovarian development and mating status. Most of the females trapped in May-July during 2010–2014 had a high mating rate and advanced level of ovarian development, suggesting that the migration of this species does not conform to the hypothesis of ‘oogenesis-flight syndrome’. The findings of the present study are beneficial to the development of forecasting systems and management strategies of <i>M</i>. <i>brassicae</i>.</p></div

Maps showing the area of East Asia (left-hand map) and the position of Beihuang Island, the searchlight trap site (right-hand map).

<p>Maps showing the area of East Asia (left-hand map) and the position of Beihuang Island, the searchlight trap site (right-hand map).</p

Maps showing the zone of East Asia and the position of Beihuang (BH) Island, the searchlight trapping site (right-hand map), relative to the Bohai Sea and Yellow Sea.

<p>Maps showing the zone of East Asia and the position of Beihuang (BH) Island, the searchlight trapping site (right-hand map), relative to the Bohai Sea and Yellow Sea.</p

Annual catches of <i>M</i>. <i>brassicae</i> in the searchlight trap on BH from 2003 to 2014.

<p>Linear model (dotted lines): <i>y</i> = 1013.4<i>x</i>-2×10⁶; <i>R</i>² = 0.9759 (2003–2008); <i>y</i> = -1067.9<i>x</i>+2×10⁶; <i>R</i>² = 0.8345 (2010–2014).</p

Proportion of mating occurrences of <i>A</i>. <i>segetum</i> females captured in the searchlight trap on BH during 2010–2013.

<p>Proportion of mating occurrences of <i>A</i>. <i>segetum</i> females captured in the searchlight trap on BH during 2010–2013.</p

Incidence of ovarian development (A) and mean proportion of sexually mature females (B) of <i>M</i>. <i>brassicae</i> captured in the searchlight trap on BH from May to September during 2010–2014.

<p>The scatter diagrams in B indicate average proportion of sexually mature females from 2010 to 2014 in each month. Bars sharing the same letter mean there were no significant differences during months at the 5%level by Tukey’s HSD tests. Linear model (dotted lines): (B) <i>y</i> = -15.165<i>x</i>+95.459; <i>R</i>² = 0.8394. Few moths were trapped in April and October, so these months are not presented.</p