112 research outputs found

    Effect of Tillage and Planting Date on Seasonal Abundance and Diversity of Predacious Ground Beetles in Cotton

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    A 2-year field study was conducted in the southern High Plains region of Texas to evaluate the effect of tillage system and cotton planting date window on seasonal abundance and activity patterns of predacious ground beetles. The experiment was deployed in a split-plot randomized block design with tillage as the main-plot factor and planting date as the subplot factor. There were two levels for each factor. The two tillage systems were conservation tillage (30% or more of the soil surface is covered with crop residue) and conventional tillage. The two cotton planting date window treatments were early May (normal planting) and early June (late planting). Five prevailing predacious ground beetles, Cicindela sexguttata F., Calosoma scrutator Drees, Pasimachus spp., Pterostichus spp., and Megacephala Carolina L. (Coleoptera: Carabidae), were monitored using pitfall traps at 2-week intervals from June 2002 to October 2003. The highest total number of ground beetles (6/trap) was observed on 9 July 2003. Cicindela sexguttata was the dominant ground dwelling predacious beetle among the five species. A significant difference between the two tillage systems was observed in the abundances of Pterostichus spp. and C. sexguttata. In 2002. significantly more Pterostichus spp. were recorded from conventional plots (0.27/trap) than were recorded from conservation tillage plots (0.05/trap). Significantly more C. sexguttata were recorded in 2003 from conservation plots (3.77/trap) than were recorded from conventional tillage plots (1.04/trap). There was a significant interaction between year and tillage treatments. However, there was no significant difference in the abundances of M. Carolina and Pasimachus spp. between the two tillage practices in either of the two years. M. Carolina numbers were significantly higher in late-planted cotton compared with those observed in normal-planted cotton. However, planting date window had no significant influence on the activity patterns of the other species. Ground beetle species abundance, diversity, and species richness were significantly higher in conservation tillage plots. This suggests that field conditions arising from the practice of conservation tillage may support higher predacious ground beetle activity than might be observed under field conditions arising from conventional tillage practices

    In silico Experimentation of Glioma Microenvironment Development and Anti-tumor Therapy

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    Tumor cells do not develop in isolation, but co-evolve with stromal cells and tumor-associated immune cells in a tumor microenvironment mediated by an array of soluble factors, forming a complex intercellular signaling network. Herein, we report an unbiased, generic model to integrate prior biochemical data and the constructed brain tumor microenvironment in silico as characterized by an intercellular signaling network comprising 5 types of cells, 15 cytokines, and 69 signaling pathways. The results show that glioma develops through three distinct phases: pre-tumor, rapid expansion, and saturation. We designed a microglia depletion therapy and observed significant benefit for virtual patients treated at the early stages but strikingly no therapeutic efficacy at all when therapy was given at a slightly later stage. Cytokine combination therapy exhibits more focused and enhanced therapeutic response even when microglia depletion therapy already fails. It was further revealed that the optimal combination depends on the molecular profile of individual patients, suggesting the need for patient stratification and personalized treatment. These results, obtained solely by observing the in silico dynamics of the glioma microenvironment with no fitting to experimental/clinical data, reflect many characteristics of human glioma development and imply new venues for treating tumors via selective targeting of microenvironmental components

    Entrepreneurial-intention constraint model: A comparative analysis among post-graduate management students in India, Singapore and Malaysia

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    YesAlthough literature on entrepreneurship has increasingly focused on intention-based models, not much emphasis has been laid on understanding the combined effect of contextual and situational factors along with support of university environment on the formation of entrepreneurial intention among students. In an effort to make up for this shortfall, by taking Theory of Planned Behavior as basic framework, the present study seeks to understand the influence of three of the most important factors, viz. (a) endogenous barriers, (b) exogenous environment, and (c) university environment and support on the entrepreneurial intention among management students. The study sample consisted of 1,097 students, wherein 526 students were from India, 252 from Singapore, and 319 were from Malaysia. The results indicates that along with positive attitude and perceived behavioral control that directly influences entrepreneurial intention, university environment and support and exogenous environment also have an indirect but significant impact on shaping of entrepreneurial intention among students. With this, it was found that exogenous environment was found to have a negative relationship with both attitude towards behavior and perceived behavioral control for all three countries.The full-text of this article will be released for public view at the end of the publisher embargo on 2 Jun 2018

    Study of pallial neurogenesis in shark embryos and the evolutionary origin of the subventricular zone

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    The dorsal part of the developing telencephalon is one of the brain areas that has suffered most drastic changes throughout vertebrate evolution. Its evolutionary increase in complexity was thought to be partly achieved by the appearance of a new neurogenic niche in the embryonic subventricular zone (SVZ). Here, a new kind of amplifying progenitors (basal progenitors) expressing Tbr2, undergo a second round of divisions, which is believed to have contributed to the expansion of the neocortex. Accordingly, the existence of a pallial SVZ has been classically considered exclusive of mammals. However, the lack of studies in ancient vertebrates precludes any clear conclusion about the evolutionary origin of the SVZ and the neurogenic mechanisms that rule pallial development. In this work, we explore pallial neurogenesis in a basal vertebrate, the shark Scyliorhinus canicula, through the study of the expression patterns of several neurogenic markers. We found that apical progenitors and radial migration are present in sharks, and therefore, their presence must be highly conserved throughout evolution. Surprisingly, we detected a subventricular band of ScTbr2-expressing cells, some of which also expressed mitotic markers, indicating that the existence of basal progenitors should be considered an ancestral condition rather than a novelty of mammals or amniotes. Finally, we report that the transcriptional program for the specification of glutamatergic pallial cells (Pax6, Tbr2, NeuroD, Tbr1) is also present in sharks. However, the segregation of these markers into different cell types is not clear yet, which may be linked to the lack of layering in anamniotesThis work was supported by the Spanish Ministerio de Economía y Competitividad-FEDER (BFU2014-5863-1P)S

    Connecting staff expectations and student understanding of professional engineering skills in a multidisciplinary design challenge

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    This paper discusses the evolution of an active learning assignment [1] for second year undergraduate biomedical engineers. An arc of assignments throughout the first two years of their study supports their understanding of the design cycle and aids in assimilation of material taught in lectures and more structured laboratory workshops [2]. The assignment - to create an item of 'smart' clothing for an athlete - was primarily designed to reinforce student learning in the areas of physiological monitoring through transducers, basic electronics and Arduino programming. A misalignment was observed between teaching staff's preconceptions of students' skills and knowledge, and the experience that the students actually bring to the assignment which influences how they approach the work, echoing the concept of the hidden curriculum [3]. This led to the team aiming to improve support of students' skills in debugging, their awareness of laboratory health and safety and links between different strands of their education through pre-assignment material, changes in teaching vocabulary and small changes in assessment. The impact of the changes has been evaluated through teaching team discussions and analysis ofshort pieces of individual reflective writing done by every student as part of their assessment before and after the material's introduction
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