6,295 research outputs found
The relationship between metabolic rate and sociability is altered by food-deprivation
Individuals vary in the extent to which they associate with conspecifics, but little is known about the energetic underpinnings of this variation in sociability. Group-living allows individuals to find food more consistently, but within groups, there can be competition for food items. Individuals with an increased metabolic rate could display decreased sociability to reduce competition. Long-term food deprivation (FD) may alter any links between sociability and metabolic rate by affecting motivation to find food.
We examined these issues in juvenile qingbo carp Spinibarbus sinensis, to understand how FD and metabolic rate affect sociability. Like many aquatic ectotherms, this species experiences seasonal bouts of FD.
Individuals were either: (i) food-deprived for 21 days; or (ii) fed a maintenance ration (control). Fish from each treatment were measured for standard metabolic rate (SMR) and tested for sociability twice: once in the presence of a control stimulus shoal and once with a food-deprived stimulus shoal.
Control individuals ventured further from stimulus shoals over a 30-min trial, while food-deprived fish did not change their distance from stimulus shoals as trials progressed. Control fish with a higher SMR were least sociable. Well-fed controls showed decreased sociability when exposed to food-deprived stimulus shoals, but there was evidence of consistency in relative sociability between exposures to different shoal types.
Results contrast with previous findings that several days of fasting causes individuals to decrease associations with conspecifics. Prolonged FD may cause individuals to highly prioritize food acquisition, and the decreased vigilance that would accompany continuous foraging may heighten the need for the antipredator benefits of shoaling. Conversely, decreased sociability in well-fed fish with a high SMR probably minimizes intraspecific competition, allowing them to satisfy an increased energetic demand while foraging. Together, these results suggest that FD – a challenge common for many ectothermic species – can affect individual sociability as well as the attractiveness of groups towards conspecifics. In addition, the lack of a link between SMR and sociability in food-deprived fish suggests that, in situations where group membership is linked to fitness, the extent of correlated selection on metabolic traits may be context-dependent
EDA: Explicit Text-Decoupling and Dense Alignment for 3D Visual Grounding
3D visual grounding aims to find the object within point clouds mentioned by
free-form natural language descriptions with rich semantic cues. However,
existing methods either extract the sentence-level features coupling all words
or focus more on object names, which would lose the word-level information or
neglect other attributes. To alleviate these issues, we present EDA that
Explicitly Decouples the textual attributes in a sentence and conducts Dense
Alignment between such fine-grained language and point cloud objects.
Specifically, we first propose a text decoupling module to produce textual
features for every semantic component. Then, we design two losses to supervise
the dense matching between two modalities: position alignment loss and semantic
alignment loss. On top of that, we further introduce a new visual grounding
task, locating objects without object names, which can thoroughly evaluate the
model's dense alignment capacity. Through experiments, we achieve
state-of-the-art performance on two widely-adopted 3D visual grounding
datasets, ScanRefer and SR3D/NR3D, and obtain absolute leadership on our
newly-proposed task. The source code will be available at
https://github.com/yanmin-wu/EDA.Comment: 16 pages with 5 pages of supplementary materia
Three-dimensional numerical study of flow characteristic and membrane fouling evolution in an enzymatic membrane reactor
In order to enhance the understanding of membrane fouling mechanism, the
hydrodynamics of granular flow in a stirred enzymatic membrane reactor was
numerically investigated in the present study. A three-dimensional Euler-Euler
model, coupled with k-e mixture turbulence model and drag function for
interphase momentum exchange, was applied to simulate the two-phase
(fluid-solid) turbulent flow. Numerical simulations of single- or two-phase
turbulent flow under various stirring speed were implemented. The numerical
results coincide very well with some published experimental data. Results for
the distributions of velocity, shear stress and turbulent kinetic energy were
provided. Our results show that the increase of stirring speed could not only
enlarge the circulation loops in the reactor, but it can also increase the
shear stress on the membrane surface and accelerate the mixing process of
granular materials. The time evolution of volumetric function of granular
materials on the membrane surface has qualitatively explained the evolution of
membrane fouling.Comment: 10 panges, 8 figure
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