Competition Versus Choice: Evolution Along a Narrow Path in \u3cem\u3eDrosophila \u3c/em\u3eβ2 Tubulin

The Drosophila melanogaster β2 protein (Dmβ2) has sustained a long evolutionary stasis for the last 60 million years (Nielsen 2006). Even small changes to the protein’s primary amino acid sequence render it non-functional, suggesting its stasis may be due to stringency in the structure/function relationship (Nielsen 2001). This project seeks to understand what has prevented Dmβ2 from evolving, with the two main hypotheses being that Dmβ2 either exists as an ideal protein configuration that competitively bests all alternates or that Dmβ2 is the only possible configuration that will support spermatogenesis in Drosophila melanogaster. In order to test these hypotheses, the ability of other proteins to rescue β2 function must be assessed. Previous work done to test β2 function used the major, non sperm-generator tubulin (β1) as a backbone to test the function of candidate sperm-generating residues. While sperm-generating residues were identified, none were sufficient to rescue fertility in a Dmβ2 null background (Nielsen 2001, Raff 2000). This project represents a different approach to analyzing the evolutionary stasis of Dmβ2 by testing the ability of a known sperm-generating ortholog from Glossina morsitans (commonly known as the tsetse fly) to rescue fertility. This sequence is 96% identical to Dmβ2 and is of particular interest because it is the closest relative to Drosophila melanogaster that possesses a variation in β2 sequence. When expressed in a Dmβ2 null background, the tsetse fly β2 (Gmβ2) generates long-tailed, fertile sperm when examined by light microscopy on testis samples and fertility tests between transgenic males and virgin wild-type females. This evidence supports the first of the two hypotheses outlined above, that β2 alternates exist but Dmβ2 is competitively superior. This shows the potential for β2 to participate in the process of evolution, potentially through allelic effects on sperm-tail length, which plays an important role in the retention of sperm in the female reproductive tract. Comparative analyses of outgroups, such as the human β2 ortholog (Hsβ3), will provide further information necessary to assess the roles of generic aspects of β2 such as motility versus more lineage-specific properties such as sperm tail length in the process of spermatogenesis

An In Depth Study into Using EMI Signatures for Appliance Identification

Energy conservation is a key factor towards long term energy sustainability. Real-time end user energy feedback, using disaggregated electric load composition, can play a pivotal role in motivating consumers towards energy conservation. Recent works have explored using high frequency conducted electromagnetic interference (EMI) on power lines as a single point sensing parameter for monitoring common home appliances. However, key questions regarding the reliability and feasibility of using EMI signatures for non-intrusive load monitoring over multiple appliances across different sensing paradigms remain unanswered. This work presents some of the key challenges towards using EMI as a unique and time invariant feature for load disaggregation. In-depth empirical evaluations of a large number of appliances in different sensing configurations are carried out, in both laboratory and real world settings. Insights into the effects of external parameters such as line impedance, background noise and appliance coupling on the EMI behavior of an appliance are realized through simulations and measurements. A generic approach for simulating the EMI behavior of an appliance that can then be used to do a detailed analysis of real world phenomenology is presented. The simulation approach is validated with EMI data from a router. Our EMI dataset - High Frequency EMI Dataset (HFED) is also released

Full-scale testing, production and cost analysis data for the advanced composite stabilizer for Boeing 737 aircraft, volume 2

The development, testing, production activities, and associated costs that were required to produce five-and-one-half advanced-composite stabilizer shipsets for Boeing 737 aircraft are defined and discussed

Modelling Emergent Patterns of Dynamic Desert Ecosystems

In many desert ecosystems vegetation is both patchy and dynamic: vegetated areas are interspersed with patches of bare ground, and both the positioning and the species composition of the vegetated areas exhibit change through time. These characteristics lead to the emergence of multi-scale patterns in vegetation that arise from complex relationships between plants, soils and transport processes. Previous attempts to probe the causes of spatial complexity and predict responses of desert ecosystems tend to be limited in their focus: models of dynamics have been developed with no consideration of the inherent patchiness in the vegetation, or else models have been developed to generate patterns with no consideration of the dynamics. Here we develop a general modelling framework for the analysis of ecosystem change in deserts that is rooted in the concept of connectivity and is derived from a detailed process-based understanding. We explicitly consider spatial interactions among multiple vegetation types and multiple resources, and our model is formulated to predict responses to a variety of endogenous and exogenous disturbances. The model is implemented in the deserts of the American Southwest both to test hypotheses of the causes of the invasion of woody shrubs, and to test its ability to reproduce 16 observed spatial differences in response to drought in the twentieth century. The model’s performance leads us to argue that vertical and lateral connectivity are key emergent properties of the ecosystem, which both control its behaviour and provide indicators of its state. If this argument is shown to be compatible with field observations, the model presented here will provide a more certain approach towards preventing further degradation of semi-arid grasslands. http://www.esajournals.org/doi/pdf/10.1890/12-1253.

Reflections on Air Capture: the political economy of active intervention in the global environment

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47530/1/10584_2005_Article_9032.pd

Generalised scalar-tensor theory in the Bianchi type I model

We use a conformal transformation to find solutions to the generalised scalar-tensor theory, with a coupling constant dependent on a scalar field, in an empty Bianchi type I model. We describe the dynamical behaviour of the metric functions for three different couplings: two exact solutions to the field equations and a qualitative one are found. They exhibit non-singular behaviours and kinetic inflation. Two of them admit both General Relativity and string theory in the low-energy limit as asymptotic cases.Comment: 14 pages, 12 figures, to appear in General Relativity and Gravitatio

Southeast Asian diversity: first insights into the complex mtDNA structure of Laos

<p>Abstract</p> <p>Background</p> <p>Vast migrations and subsequent assimilation processes have shaped the genetic composition of Southeast Asia, an area of close contact between several major ethnic groups. To better characterize the genetic variation of this region, we analyzed the entire mtDNA control region of 214 unrelated donors from Laos according to highest forensic quality standards. To detail the phylogeny, we inspected selected SNPs from the mtDNA coding region. For <it>a posteriori </it>data quality control, quasi-median network constructions and autosomal STR typing were performed. In order to describe the mtDNA setup of Laos more thoroughly, the data were subjected to population genetic comparisons with 16 East Asian groups.</p> <p>Results</p> <p>The Laos sample exhibited ample mtDNA diversity, reflecting the huge number of ethnic groups listed. We found several new, so far undescribed mtDNA lineages in this dataset and surrounding populations. The Laos population was characteristic in terms of haplotype composition and genetic structure, however, genetic comparisons with other Southeast Asian populations revealed limited, but significant genetic differentiation. Notable differences in the maternal relationship to the major indigenous Southeast Asian ethnolinguistic groups were detected.</p> <p>Conclusions</p> <p>In this study, we portray the great mtDNA variety of Laos for the first time. Our findings will contribute to clarify the migration history of the region. They encourage setting up regional and subpopulation databases, especially for forensic applications. The Laotian sequences will be incorporated into the collaborative EMPOP mtDNA database <url>http://www.empop.org</url> upon publication and will be available as the first mtDNA reference data for this country.</p