scholarly journals Chemically Insignificant Social Parasites Exhibit More Anti-Dehydration Behaviors than Their Hosts

Insects ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1006
Author(s):  
Maria Cristina Lorenzi
Keyword(s):  
Cuticular Hydrocarbons ◽  
Host Resistance ◽  
Desiccation Stress ◽  
Front Face ◽  
Social Parasites ◽  
Behavioral Adaptations ◽  
The Social ◽  
Back Face ◽  
Host Detection ◽  
Polistes Biglumis

Social parasites have evolved adaptations to overcome host resistance as they infiltrate host colonies and establish there. Among the chemical adaptations, a few species are chemically “insignificant”; they are poor in recognition cues (cuticular hydrocarbons) and evade host detection. As cuticular hydrocarbons also serve a waterproofing function, chemical insignificance is beneficial as it protects parasites from being detected but is potentially harmful because it exposes parasites to desiccation stress. Here I tested whether the social parasites Polistes atrimandibularis employ behavioral water-saving strategies when they live at Polistes biglumis colonies. Observations in the field showed that parasites were less active than their cohabiting host foundresses, spent more time at the nest, and rested in the shadowy, back face of the nest, rather than at the front face, which contradicted expectations for the use of space for dominant females—typically, dominants rest at the nest front-face. These data suggest that behavioral adaptations might promote resistance to desiccation stress in chemical insignificant social parasites.

Impact Analysis of Honeycomb Core Sandwich Panels

2020 ◽  
Author(s):  
Shah Alam ◽  
Damodar Khanal
Keyword(s):  
Sandwich Panels ◽  
Sheet Thickness ◽  
Composite Panel ◽  
Face Sheet ◽  
Impact Behavior ◽  
Front Face ◽  
Geometrical Parameters ◽  
Honeycomb Core ◽  
Back Face ◽  
The Impact

Abstract The goal of this paper is to analyze the impact behavior among geometrically different sandwich panels shown upon impact velocities. Initially, composite model with aluminum honeycomb core and Kevlar (K29) face sheets is developed in ABAQUS/Explicit and different impact velocities are applied. Keeping other parameters constant, model is simulated with T800S/epoxy face sheets. Residual velocities, energy absorption (%), and maximum deformation depth is calculated for sandwich panel for both models at five different velocities by executing finite element analysis. Once the better material is found for face sheets, process is extended by varying the ratio of front face sheet thickness to back face sheet thickness keeping other geometrical parameters constant to find the better geometry. Also, comparison of impact responses of sandwich composite panel on different ratio of front face sheet thickness to back face sheet thickness is done and validated with other results available in literature.

The turning couples on an elliptic particle settling in a vertical channel

1994 ◽  
Vol 271 ◽  
pp. 1-16 ◽  
Author(s):  
Peter Y. Huang ◽  
Jimmy Feng ◽  
Daniel D. Joseph
Keyword(s):  
Shear Stress ◽  
Vortex Shedding ◽  
Stokes Equations ◽  
Vertical Channel ◽  
Navier Stokes ◽  
Front Face ◽  
Two Dimensional ◽  
Navier Stokes Equations ◽  
Back Face ◽  
The One

We do a direct two-dimensional finite-elment simulation of the Navier–Stokes equations and compute the forces which turn an ellipse settling in a vertical channel of viscous fluid in a regime in which the ellipse oscillates under the action of vortex shedding. Turning this way and that is induced by large and unequal values of negative pressure at the rear separation points which are here identified with the two points on the back face where the shear stress vanishes. The main restoring mechanism which turns the broadside of the ellipse perpendicular to the fall is the high pressure at the ‘stagnation point’ on the front face, as in potential flow, which is here identified with the one point on the front face where the shear stress vanishes.

Four-Point Bending of Metallic I-Core Sandwich Beams With Longitudinal Girder

2019 ◽  
Author(s):  
Wenwei Hu ◽  
Jun Liu ◽  
Pan Zhang ◽  
Yuansheng Cheng
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Numerical Model ◽  
Sandwich Structure ◽  
Front Face ◽  
Beam Structure ◽  
Hull Structure ◽  
Bending Load ◽  
Back Face ◽  
Bending Loads

Abstract I-core sandwich structure has great potential in the application of hull structure construction due to its high specific strength and relatively simple manufacturing process. The topic on the study of mechanical properties of I-core sandwich structure under bending loads is of interest to structural designers since the structure is often subjected to bending loads in engineering applications. In this paper, a metallic I-core sandwich beam with longitudinal girder was designed and manufactured using laser welding technique, and finally tested under four-point bend loading. The elastic-plastic behaviors and the ultimate load carrying capacity of this novel beam structure were obtained. A numerical model was developed to investigate the mechanical properties of this novel beam structure by finite element method. The results of the numerical model were compared with experimental data. Stress components of the front face and back face in the failure process were analyzed and discussed to investigate the failure of them. Results showed that the huge local bending stresses of plate caused the failure of the front face and back face. Finally, an improved scheme for the test was proposed to provide a pure bending load, which was proved by finite element simulation. All the findings aim to guide the engineering application of this structure.

Closed-Loop Control of Weld Penetration Using Front-Face Vision Sensing

1993 ◽  
Vol 207 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Y M Zhang ◽  
R Kovacevic ◽  
L Wu
Keyword(s):  
Arc Welding ◽  
Dynamic Modelling ◽  
Front Face ◽  
Weld Penetration ◽  
Loop Control ◽  
Vision Sensing ◽  
Gas Tungsten Arc ◽  
Full Penetration ◽  
Back Face ◽  
The Relationship

Feedback control of weld penetration based on a front-face sensor is a challenging problem in the field of welding. A novel vision-based approach is proposed in this paper for full penetration control of the gas tungsten arc welding (GT AW). Owing to the relationship between the front-face weld geometry and back-face weld width (representation of the full penetration state), which has been reported earlier by the present authors, it is possible to use the front-face geometry as feedback of full penetration. Based on the dynamic modelling and the analysis of accepted adaptive control algorithms, an adaptive predictive decoupling controller is developed. Simulations and experiments under a variety of welding conditions have been conducted to verify the effectiveness of the proposed approach and controller.

Cuticular hydrocarbons and reproductive status in the social wasp Polistes dominulus

2001 ◽  
Vol 49 (5) ◽  
pp. 401-409 ◽  
Author(s):  
Matthew F. Sledge ◽  
Francesca Boscaro ◽  
Stefano Turillazzi
Keyword(s):  
Cuticular Hydrocarbons ◽  
Social Wasp ◽  
Reproductive Status ◽  
Polistes Dominulus ◽  
The Social

Colony kin structure and breeding patterns in the social wasp, Polistes biglumis

2011 ◽  
Vol 58 (3) ◽  
pp. 345-355 ◽  
Author(s):  
P. Seppä ◽  
J. Fogelqvist ◽  
N. Gyllenstrand ◽  
M. C. Lorenzi
Keyword(s):  
Social Wasp ◽  
The Social ◽  
Kin Structure ◽  
Polistes Biglumis

scholarly journals USING THE RASINTERFOAM CFD MODEL FOR WAVE TRANSFORMATION AND COASTAL MODELLING

2011 ◽  
Vol 1 (32) ◽  
pp. 23 ◽  
Author(s):  
Gerald Charles John Morgan ◽  
Jun Zang ◽  
Deborah Greaves ◽  
Andrew Heath ◽  
Chris Whitlow ◽  
...  
Keyword(s):  
Continuum Mechanics ◽  
Experimental Results ◽  
Sensitivity Analyses ◽  
Wave Transformation ◽  
Front Face ◽  
Cfd Model ◽  
Coastal Modelling ◽  
Back Face ◽  
Mesh Density ◽  
Coarse Meshes

The CFD model, rasInterFoam, part of the OpenFOAM library for continuum mechanics, is used to reproduce experimental results for the propagation of monochromatic waves over a submerged bar. The model is shown to reproduce the experimental results very well on the front face and top of the bar, and give adequate results on the back face, even on extremely coarse meshes. Sensitivity analyses are presented for the model results, investigating the dependence on mesh density and discretisation scheme of the model. The modeling of the wave transformations in the model is shown to be broadly insensitive to these parameters within the ranges tested.

scholarly journals Early assessment of knowledge, attitudes, anxiety and behavioral adaptations of Connecticut residents to COVID-19

2020 ◽  
Author(s):  
Toan Ha ◽  
Stephen Schensul ◽  
Judy Lewis ◽  
Stacey Brown
Keyword(s):  
Social Isolation ◽  
Scientific Information ◽  
Multivariate Logistic Regression Analysis ◽  
Cross Sectional Study ◽  
Older Age ◽  
Protective Behavior ◽  
Early Assessment ◽  
Cross Sectional ◽  
Behavioral Adaptations ◽  
The Social

Objectives. To assess knowledge, attitudes, anxiety and behavioral adaptations to COVID-19. Methods. A cross-sectional study was conducted among non-healthcare-related participants after a stringent stay-at-home directive was implemented. Multivariate logistic regression analysis was conducted to identify factors associated with anxiety, perceived seriousness of COVID-19 and loneliness. Results. A total of 464 participants responded to the survey. Most participants recognized cough, shortness of breath and fever as primary symptoms of COVID-19. Nearly 50% reported high levels of anxiety to COVID-19 and 48% reported being loneliness during the social isolation. Those with higher level of COVID-19 knowledge had 1.20 times higher levels with anxiety. Being married had 1.79 times higher levels of anxiety about COVID-19. Older age was associated with loneliness during the social isolation. Older age was also associated with taking the pandemic seriously. Females were less likely to report loneliness than males. Conclusions. It is crucial for the public health authorities not only provide accurate and scientific information about the COVID-19 promoting protective behavior changes but also to minimize anxiety through supportive messages and recommendations for positive coping strategies and timely offering of counseling services for those in need.

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