11,633 research outputs found
Development of Multiple Polymorphic Microsatellite Markers for Ceratina calcarata (Hymenoptera: Apidae) Using Genome-Wide Analysis
The small carpenter bee, Ceratina calcarata (Robertson), is a widespread native pollinator across eastern North America. The behavioral ecology and nesting biology of C. calcarata has been relatively well-studied and the species is emerging as a model organism for both native pollinator and social evolution research. C. calcarata is subsocial: reproductively mature females provide extended maternal care to their brood. As such, studies of C. calcarata may also reveal patterns of relatedness and demography unique to primitively social Hymenoptera. Here, we present 21 microsatellite loci, isolated from the recently completed C. calcarata genome. Screening in 39 individuals across their distribution revealed that no loci were in linkage disequilibrium, nor did any deviate significantly from Hardy-Weinberg following sequential Bonferroni correction. Allele count ranged from 2 to 14, and observed and expected heterozygosities ranged from 0.08 to 0.82 (mean 0.47) and 0.26 to 0.88 (mean 0.56), respectively. These markers will enable studies of population-wide genetic structuring across C. calcarata’s distribution. Such tools will also allow for exploration of between and within-colony relatedness in this subsocial native pollinator
Supergravitational Conformal Galileons
The worldvolume actions of 3+1 dimensional bosonic branes embedded in a
five-dimensional bulk space can lead to important effective field theories,
such as the DBI conformal Galileons, and may, when the Null Energy Condition is
violated, play an essential role in cosmological theories of the early
universe. These include Galileon Genesis and "bouncing" cosmology, where a
pre-Big Bang contracting phase bounces smoothly to the presently observed
expanding universe. Perhaps the most natural arena for such branes to arise is
within the context of superstring and -theory vacua. Here, not only are
branes required for the consistency of the theory, but, in many cases, the
exact spectrum of particle physics occurs at low energy. However, such theories
have the additional constraint that they must be supersymmetric. This
motivates us to compute the worldvolume actions of supersymmetric
three-branes, first in flat superspace and then to generalize them to
supergravitation. In this paper, for simplicity, we begin the process, not
within the context of a superstring vacuum but, rather, for the conformal
Galileons arising on a co-dimension one brane embedded in a maximally symmetric
bulk space. We proceed to supersymmetrize the associated
worldvolume theory and then generalize the results to supergravity,
opening the door to possible new cosmological scenarios.Comment: 39 pages, 1 figure. Version 4: Typos corrected, minor points on
notation clarifie
The Evolution of Cell Communication: The Road not Taken.
In the post-genomic era the complex problem of evolutionary biology can be tackled from the top-down, the bottom-up, or from the middle-out. Given the emergent and contingent nature of this process, we have chosen to take the latter approach, both as a mechanistic link to developmental biology and as a rational means of identifying signaling mechanisms based on their functional genomic significance. Using this approach, we have been able to configure a working model for lung evolution by reverse-engineering lung surfactant from the mammalian lung to the swim bladder of fish. Based on this archetypal cell-molecular model, we have reduced evolutionary biology to cell communication, starting with unicellular organisms communicating with the environment, followed by cell-cell communication to generate metazoa, culminating in the communication of genetic information between generations, i.e. reproduction. This model predicts the evolution of physiologic systems-including development, homeostasis, disease, regeneration/repair, and aging- as a logical consequence of biology reducing entropy. This approach provides a novel and robust way of formulating refutable, testable hypotheses to determine the ultimate origins and first principles of physiology, providing candidate genes for phenotypes hypothesized to have mediated evolutionary changes in structure and/or function. Ultimately, it will form the basis for predictive medicine and molecular bioethics, rather than merely showing associations between genes and pathology, which is an unequivocal Just So Story. In this new age of genomics, our reach must exceed our grasp
Dynamic Competition Networks: detecting alliances and leaders
We consider social networks of competing agents that evolve dynamically over
time. Such dynamic competition networks are directed, where a directed edge
from nodes to corresponds a negative social interaction. We present a
novel hypothesis that serves as a predictive tool to uncover alliances and
leaders within dynamic competition networks. Our focus is in the present study
is to validate it on competitive networks arising from social game shows such
as Survivor and Big Brother
- …
