Unmated queens in the primitively eusocial wasp Ropalidia marginata (Lep.) (Hymenoptera: Vespidae)

In the primitively eusocial tropical wasp Ropalidia marginata, five out of eleven colonies studied had an unmated female as their queen. In two colonies this was the case despite the presence of another mated individual in the colony. We found no detectable differences between colonies with unmated queens and those with mated queens. We argue that in species such as R. marginata, where intracolony relatedness is expected to be low and where sociality is likely to be maintained because several individuals have opportunities for direct reproduction in the future, individual selection is likely to override "the good of the colony" and lead to such phenomena as that of unmated queens

Ropalidia rufoplagiata: a polistine wasp society probably lacking permanent reproductive division of labour

Ropalidia rufoplagiata Cameron (Hymenoptera: Vespidae), a polistine species from penisular India, appears to be unique among all known primitively eusocial wasps. A total of 33 out of 46 identified females from an observed colony were found to oviposit on 1-17 occasions. No single predominant egg-layer could be identified during the 45-day period. Of the 17 dissected egg-layers, 12 were mated. All egg-layers showed several oviposition-related behavioural patterns including systematic, but indiscriminate, cannibalism of eggs and larvae, cleaning of empty cells, and guarding of freshly-laid eggs. There was no correlation between the egg-laying activity of the females (whether mated or not), oophagy, and their position in the dominance hierarchy. All nest-maintenance activities were performed exclusively by the egg-layers, while the non-egg-layers were mainly involved in the extranidal task offoraging. No significant morphometric differences between egg-layers and foragers could be discerned. Almost all the older individuals in the colony were egg-layers, while foragers were mainly younger animals. Such a temporal differentiation in reproductive labour suggests the absence of a permanent reproductive caste in this species

Queen success is correlated with worker-brood genetic relatedness in a primitively eusocial wasp (Ropalidia marginata)

Ropalidia marginata is a primitively eusocial polistine wasp in which, although there is only one queen at any given time, frequent queen replacements lead to a system of serial polygyny. One of the most striking features of this system is the enormous variation in the success of different queens. Measuring queen success as queen tenure, total number of offspring produced, number of offspring produced per day of tenure, and proportion of eggs laid that develop into adults, we show here that each measure of queen success is correlated with worker-brood genetic relatedness and not correlated with worker:brood ratio or the age of the queen at takeover. We interpret these results as meaning that queens are better able to obtain the cooperation of workers when worker-brood genetic relatedness is high

Dynamic analysis of MCF-10A and MCF-7: A simulation approach

Cancer is one of the leading causes of death in the world. Breast cancer is the most common form of cancer among women and is responsible for 15 % of all cancer related deaths. Though there are significant advancements in cancer treatment strategies, clinical tumour treatment methods currently employed are often accompanied by severe side effects as they induce damage to the normal cells along with the cancer cells. The alterations in the biophysical and biomechanical properties of a cell as it undergoes transformation from a normal to cancerous cell results in changes in its dynamic characteristics. These changes can be utilised to induce selective cytotoxicity of tumour cells. In the present study, two simulation models (homogenous and non-homogenous) of normal (MCF-10A) and cancerous (MCF-7) breast cells are developed. A finite element approach using Ansys is adopted to investigate the variation in dynamic characteristics of the cells using the two modelling approaches. Results indicate that the natural frequencies of cells modelled as a homogenous system is greater than that of cells whose sub-cellular material properties are considered for analysis. A comparison of the first four natural frequencies using the two modelling approaches for both MCF-10A and MCF-7 cells are illustrated and the corresponding mode shapes reported. A plot highlighting the variation in the natural frequencies of MCF-10A and MCF-7 using the two modelling approaches is presented

Predicting the potential geographical distribution of the sugarcane woolly aphid using GARP and DIVA-GIS

Management of newly emerging pests and diseases has often been limited by the lack of forecasting systems that could predict the route(s) of spread and potential geographical distribution of the species. While the importance of the patterns of spread of invasive organisms has always been realized, the necessary analytical tools for making reasonably robust predictions are limited. In recent years however, availability of ecological and climatologic data,computational abilities to process huge data sets, and development of suitable algorithms have helped in a better understanding of the patterns of spread of the invasive species. For instance, algorithms such as Genetic Algorithm for Rule Set Prediction (GARP) and DIVA-GIS, are being successfully employed in a wide range of situations for predicting the spread of invasive species1–4. Here, we explore these two modelling approaches to predict the potential geographical distribution of a newly emerging insect pest, the sugarcane woolly aphid that has played havoc with crops in parts of Maharashtra and Karnataka5

Cell dynamics and natural frequencies: scaling and shape matters

Cell dynamics is one of the most investigated areas under the field of biomechanics. Scaling plays a crucial role in determining the dynamic characteristics of biological systems. In the present investigation, cuboidal and cylindrical models of different scales are analysed to depict the dependence of natural frequency on the scaling factors. Three approaches, namely lumped mass system, finite element model (FEM) and numerical approach using Ansys are used to determine the fundamental natural frequencies. Different scaling factors, namely nano, micro (original size), millimeter and meter are considered for the analysis. The results indicate that the natural frequency varies inversely with the size of the cell by the same factor. A simple mathematical relation is derived to support this claim. Results are illustrated with numerical examples and corresponding mode shapes are reported

Analysis of the Relationship between Exhaust Gas Temperature (EGT in 0 C) and Nitrogen oxides (NO x in ppm) during Performance and Emission tests on various Biodiesels derived from edible and non-edible oils and their blends

Abstract Present study is concerned about analyzing and establishing the relationship between EGT an

Finite element modelling and dynamic characteristic analysis of the human CTL-Spine

Persistent exposure to whole body vibrations is the fundamental cause for lower back pain and disc degeneration. With an increasing amount of population exposed to whole body vibrations, a significant number of people experience fatal spine diseases. Substantial research is carried out to reduce the risk of spinal injuries. The dynamic characteristics of the cervical, thoracic and lumbar (CTL) region are studied extensively as individual sections of the spine. Few studies have focused on the CTL spine as an assembly of the three segments. In the present work, an authentic three dimensional geometrical model of the cervical, thoracic and lumbar spine is developed in mimics considering its natural curvature and the intervertebral discs are modeled in Design modeler. The natural frequency and mode shapes of the CTL spine are extracted using free vibration modal analysis considering 4.5 kg point mass on C1 vertebra and distributed mass of 40 kg on the CTL spine in Ansys Workbench. Six natural frequencies and their corresponding vibration modes are obtained from the finite element model. The results of this study aims to provide a reliable model for further biomechanical analysis and ergonomics