Culture-independent identification of gut bacteria in fourth-instar red imported fire ant, Solenopsis invicta Buren, larvae

Red imported fire ants (RIFA), Solenopsis invicta Buren, are medical, urban, and agricultural pests from South America. Fourth-instar larvae are used by the colony to digest solid food and then regurgitate it for consumption by workers and queens. Larvae are an ideal source of investigations of obligate endosymbiotic bacteria possibly involved in nutrient distributions. I attempted to first identify what bacteria species are in the guts of larvae followed by antibiotic and microscopy work to further study their roles in the ants. The composition of the bacterial community in fire ant larvae was described with culture-independent methods utilizing 16S rDNA sequencing. The 16S rRNA gene was directly amplified from mixed-population DNA of whole fire ant larval guts and cloned into Escherichia coli. Bacterial communities from three geographically separated RIFA colonies were examined. Sequenced bacterial clones from guts were determined to be predominantly from the phylum Proteobacteria and the family Enterobacteriaceae. The colony from Baton Rouge had 34 identified species, 25 identified species from the Rosepine colony, and nine from the Bogalusa colony. None of the identified bacteria were closely related to known coadapted endosymbionts from other insect species. Bacterial inventories from each location provided little evidence of common bacteria among them. Even though Klebsiella pneumoniae appeared in all three colonies, its biology suggested that it came from the environment. Obligate symbiotic bacteria, if present should be present in all larvae regardless of physical location. Antibiotic treatments indicated that ants were not affected by clearing the guts of microorganisms. Clearing of obligate symbiotic bacteria should have detrimental effects on ant mortality. Since no significant change was found, obligate symbiosis is not likely to be present between fire ants and their gut bacteria. I was unable to detect bacteriocytes in the guts of larvae using light and electron microscopy, providing further data against an obligate symbiotic relationship. In this study I did not detect the presence of common symbiotic bacteria in the guts of RIFA larvae among the colonies. Bacteria communities appeared to be unique to each colony and were determined by the food and environment

Asteroseismology of 16000 Kepler Red Giants: Global Oscillation Parameters, Masses, and Radii

The Kepler mission has provided exquisite data to perform an ensemble asteroseismic analysis on evolved stars. In this work we systematically characterize solar-like oscillations and granulation for 16,094 oscillating red giants, using end-of-mission long-cadence data. We produced a homogeneous catalog of the frequency of maximum power (typical uncertainty $\sigma_{\nu_{\rm max}}$=1.6\%), the mean large frequency separation ($\sigma_{\Delta\nu}$=0.6\%), oscillation amplitude ($\sigma_{\rm A}$=4.7\%), granulation power ($\sigma_{\rm gran}$=8.6\%), power excess width ($\sigma_{\rm width}$=8.8\%), seismically-derived stellar mass ($\sigma_{\rm M}$=7.8\%), radius ($\sigma_{\rm R}$=2.9\%), and thus surface gravity ($\sigma_{\log g}$=0.01 dex). Thanks to the large red giant sample, we confirm that red-giant-branch (RGB) and helium-core-burning (HeB) stars collectively differ in the distribution of oscillation amplitude, granulation power, and width of power excess, which is mainly due to the mass difference. The distribution of oscillation amplitudes shows an extremely sharp upper edge at fixed $\nu_{\rm max}$, which might hold clues to understand the excitation and damping mechanisms of the oscillation modes. We find both oscillation amplitude and granulation power depend on metallicity, causing a spread of 15\% in oscillation amplitudes and a spread of 25\% in granulation power from [Fe/H]=-0.7 to 0.5 dex. Our asteroseismic stellar properties can be used as reliable distance indicators and age proxies for mapping and dating galactic stellar populations observed by Kepler. They will also provide an excellent opportunity to test asteroseismology using Gaia parallaxes, and lift degeneracies in deriving atmospheric parameters in large spectroscopic surveys such as APOGEE and LAMOST.Comment: Accepted for publication in ApJS. Both table 1 and 2 are available for download as ancillary file

Auto-configuration of Savants in a complex, variable network

Thesis (M. Eng. and S.B.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Includes bibliographical references (p. 63-64).In this thesis, present a system design that enables Savants to automatically configure both their network settings and their required application programs when connected to an intelligent data management and application system. Savants are intelligent routers in a large network used to manage the data and events related to communications with electronic identification tags [10]. The ubiquitous nature of the identification tags and the access points that communicate with them requires an information and management system that is equally ubiquitous and able to deal with huge volumes of data. The Savant systems were designed to be such a ubiquitous information and management system. Deploying any ubiquitous system is difficult, and automation is required to streamline its deployment and improve system management, reliability, and performance. My solution to this auto-configuration problem uses NETCONF as a standard language and protocol for configuration communication among Savants. It also uses the Content-Addressable Network (CAN) as a discovery service to help Savants locate configuration information, since a new Savant may not have information about the network structure. With these tools, new Savants can configure themselves automatically with the help of other Savants.(cont.) Specifically, they can configure their network settings, download and set up software, and integrate with network distributed applications. Future work could expand upon my project by studying an implementation, making provisions for resource-limited Savants, or improving security.by Joseph Hon Yu.M.Eng.and S.B

trans-Bis[1-(2-anilino-2-oxoeth­yl)-3-benzyl-1H-imidazol-2-yl]palladium(II) methanol disolvate

In the title compound, [Pd(C18H16N3O)2]·2CH3OH, the PdII atom is located on a crystallographic inversion center. It has a square-planar coordination geometry, with the two bidentate ligands coordinated in a trans fashion via the carbene C atom and the amido N atoms. The methanol solvent mol­ecules form O—H⋯O hydrogen bonds with the complex. Additional non-classical inter­molecular C—H⋯O hydrogen bonds link the complexes into a two-dimensional network parallel to (001)

The Impress Context Store: A Coordination Framework for Context-Aware Systems

The dream of weaving technology into our everyday fabric of life is recently being made possible by advances in ubiquitous computing and sensor technologies. Countless sensors of various sizes have made their way into everyday commercial applications. Many projects aim to explore new ways to utilize these new technologies to aid and interact with the general population. Context-aware systems use available context information to assist users automatically, without explicit user input. By inferring user intent and configuring the system proactively for each user, context-aware systems are an integral part of achieving user-friendly ubiquitous computing environments. A common issue with building a distributed context-aware system is the need to develop a supporting infrastructure providing features such as storage, distributed messaging, and security, before the real work on processing context information can be done. This thesis proposes a coordination framework that provides an effective common foundation for context-aware systems. The separation between the context-processing logic component and the underlying supporting foundation allows researchers to focus their energy at the context-processing part of the system, instead of spending their time re-inventing the supporting infrastructure. As part of an ongoing project, Impress, the framework uses the open standard, Jabber, as its communication protocol. The Publish-Subscribe (pubsub) extension to Jabber provides interesting features that match those needed by a context-aware system. The main contribution of this thesis is the design and implementation of a coordination framework, called the Impress Context Store, that provides an effective common foundation for context-aware systems. The separation between the context-processing logic and the underlying supporting foundation allows researchers to focus their energy at the context-processing part of the system, instead of spending their time re-inventing the supporting infrastructure