5,147 research outputs found
Food-chain competition influences gene's size
We have analysed an effect of the Bak-Sneppen predator-prey food-chain
self-organization on nucleotide content of evolving species. In our model,
genomes of the species under consideration have been represented by their
nucleotide genomic fraction and we have applied two-parameter Kimura model of
substitutions to include the changes of the fraction in time. The initial
nucleotide fraction and substitution rates were decided with the help of random
number generator. Deviation of the genomic nucleotide fraction from its
equilibrium value was playing the role of the fitness parameter, , in
Bak-Sneppen model. Our finding is, that the higher is the value of the
threshold fitness, during the evolution course, the more frequent are large
fluctuations in number of species with strongly differentiated nucleotide
content; and it is more often the case that the oldest species, which survive
the food-chain competition, might have specific nucleotide fraction making
possible generating long genesComment: 11 pages including 7 figure
Climate Change and Animals
Climate change is already having adverse effects on animal life, and those effects are likely to prove devastating in the future. Nonetheless, the relevant harms to animals have yet to become a serious part of the analysis of climate change policy. Even if animals and species are valued solely by reference to human preferences, inclusion of their welfare dramatically increases the argument for aggressive responses to climate change. We estimate that, even under conservative assumptions about valuation, losses to nonhuman life might run into the hundreds of billions of dollars annually. Whatever the precise figure, the general conclusion is clear: An appreciation of the likely loss of animal life leads to a massive increase in the assessment of the overall damage and cost of climate change
THE EFFECTS OF USER PARTICIPATION ON SYSTEM SUCCESS: TOWARD A CONTINGENCY THEORY OF USER SATESFACTION
User participation is an important construct in IS research. It is also a frequently employed practical implementation strategy. However, research findings concerning the effects of user participation on system success are mixed and inconclusive. This study reviews a contingency theory of attitude change, proposes competing models, and empirically tests the models in end-user computing involving multiple end-user groups. Results lend support to the Cognition Fit Model. Other models receive only partial support
Overlapping genes in the human and mouse genomes
<p>Abstract</p> <p>Background</p> <p>Increasing evidence suggests that overlapping genes are much more common in eukaryotic genomes than previously thought. In this study we identified and characterized the overlapping genes in a set of 13,484 pairs of human-mouse orthologous genes.</p> <p>Results</p> <p>About 10% of the genes under study are overlapping genes, the majority of which are different-strand overlaps. The majority of the same-strand overlaps are embedded forms, whereas most different-strand overlaps are not embedded and in the convergent transcription orientation. Most of the same-strand overlapping gene pairs show at least a tenfold difference in length, much larger than the length difference between non-overlapping neighboring gene pairs. The length difference between the two different-strand overlapping genes is less dramatic. Over 27% of the different-strand-overlap relationships are shared between human and mouse, compared to only ~8% conservation for same-strand-overlap relationships. More than 96% of the same-strand and different-strand overlaps that are not shared between human and mouse have both genes located on the same chromosomes in the species that does not show the overlap. We examined the causes of transition between the overlapping and non-overlapping states in the two species and found that 3' UTR change plays an important role in the transition.</p> <p>Conclusion</p> <p>Our study contributes to the understanding of the evolutionary transition between overlapping genes and non-overlapping genes and demonstrates the high rates of evolutionary changes in the un-translated regions.</p
Embedding initial data for black hole collisions
We discuss isometric embedding diagrams for the visualization of initial data
for the problem of the head-on collision of two black holes. The problem of
constructing the embedding diagrams is explicitly presented for the best
studied initial data, the Misner geometry. We present a partial solution of the
embedding diagrams and discuss issues related to completing the solution.Comment: (27pp text, 11 figures
Near-martingale Property of Anticipating Stochastic Integration
A stochastic process Xt is called a near-martingale with respect to a filtration {Ft} if E[Xt|Fs] = E[Xs|Fs] for all s ≤ t. It is called a near- submartingale with respect to {Ft} if E[Xt|Fs] ≥ E[Xs|Fs] for all s ≤ t. Near-martingale property is the analogue of martingale property when the Itô integral is extended to non-adapted integrands. We prove that Xt is a near-martingale (near-submartingale) if and only if E[Xt|Ft] is a martingale (near-submartingale, respectively). Doob-Meyer decomposition theorem is extended to near-submartingale. We study stochastic differential equations with anticipating initial conditions and obtain a relationship between such equations and the associated stochastic differential equations of the Itô type. © 2018 International Society for Bayesian Analysis
Designing a Microcontroller Training Platform for Active Distance Learning Engineering and Technology Students
This is an active distance-learning project that addresses the hands-on microprocessor/ mi-crocontroller-related courses. A research team designed a low-cost training system with supporting instructional materials to assist the teaching of these concepts. Individual laboratory activities are being developed to reinforce student learning and skill development in programming concepts. This basic system format eventually will support an array of engineering and technology courses. This project involves two community colleges, Blue Ridge Community College (BRCC) and Olympic College (OC), and a four-year university, Old Dominion University (ODU), in a collaborative research team to design and develop a specific PIC microcontroller training system with custom-designed software and curriculum materials to support related engineering technology courses. The functions of the hardware and software cover different areas of engineering technology courses and majors to maximize the use of the microcon- troller training system
The development of a program analysis environment for Ada
A unit level, Ada software module testing system, called Query Utility Environment for Software Testing of Ada (QUEST/Ada), is described. The project calls for the design and development of a prototype system. QUEST/Ada design began with a definition of the overall system structure and a description of component dependencies. The project team was divided into three groups to resolve the preliminary designs of the parser/scanner: the test data generator, and the test coverage analyzer. The Phase 1 report is a working document from which the system documentation will evolve. It provides history, a guide to report sections, a literature review, the definition of the system structure and high level interfaces, descriptions of the prototype scope, the three major components, and the plan for the remainder of the project. The appendices include specifications, statistics, two papers derived from the current research, a preliminary users' manual, and the proposal and work plan for Phase 2
Design and Analysis of an Air Filter Sensor for a Residential Heating and Cooling System
This is a design project of an air-filter sensor to be used in home heating and cooling system. The project includes conceptual design, analysis, implementation, tests and modifications. First, the air quality and power consumption between a clean air filter and a dirty air filter is studied. Then, a photo sensor circuit with an ultra high brightness LED emitter and a phototransistor receiver is used to detect dust particles. A red warning LED lights up when a specified amount of dust is collected on the filter and blocks the light beam between the emitter and the receiver. The emitter and receiver are mounted on a simple fixture and can be easily fitted on any air filter. In addition, the cost analysis shows that this design can significantly reduce the electricity bill if the filters are properly replaced
Sequence determination of protected oligodeoxyribonucleotides containing phosphotriester linkages by californium-252 plasma desorption mass spectrometry.
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