Genetic programming: the ratio of crossover to mutation as a function of time

This article studies the sub-tree operators: mutation and crossover, within the context of Genetic Programming. Two standard problems, symbolic linear regression and a non-linear tree, were presented to the algorithm at each stage. The behaviour of the operators in regard to fitness is first established, followed by an analysis of the most optimal ratio between crossover and mutation. Subsequently, three algorithms are presented as candidates to dynamically learn the most optimal level of this ratio. The results of each algorithm are then compared to each other and the traditional constant ratio

Isolation and integration in education

ArticleMS201

mRNA Poly(A) tail: a 3\u27 Enhancer of Translational Initiation: a Thesis

Most eukaryotic mRNAs have a sequence of polyadenylic acid [poly(A)] at their 3\u27-termini. Although it has been almost two decades since the discovery of these poly(A) tracts, their function(s) have yet to be clarified. Earlier results from our laboratory led us to propose that poly(A) has a role in translation. More specifically, we proposed that an interaction of the cytoplasmic poly(A)-binding protein (PABP) with a critical minimum length of poly(A) facilitates the initiation of translation of poly(A)+, but not poly(A)-, mRNAs. The results of several different experimental approaches have provided evidence which indirectly supports this hypothesis. These results include: 1) the correlation of specific changes in mRNA poly(A) tail length with translational efficiency in vivo and in vitro; 2) correlations between the abundance and stability of PABPs and the rate of translational initiation in vivo and in vitro; and 3) the demonstration that exogenous poly(A) is a potent and specific inhibitor of the in vitro translation of poly(A)+, but not poly(A)-mRNAs. To evaluate the hypothesis that the 3\u27-poly(A) tract of mRNA plays a role in translational initiation, we have constructed derivatives of pSP65 which direct the in vitro synthesis of mRNAs with different poly(A) tail lengths and compared, in reticulocyte extracts, the relative efficiencies with which such mRNAs are translated, degraded, recruited into polysomes, and assembled into mRNPs or intermediates in the translational initiation pathway. Relative to mRNAs which are polyadenylated, we find that poly(A)- mRNAs have a reduced translational capacity which is not due to an increase in their decay rates, but is attributable to a reduction in their efficiency of recruitment into polysomes. The defect in poly(A)- mRNAs affects a late step in translational initiation, is distinct from the phenotype associated with cap-deficient mRNAs, and results in a reduced ability to form 80S initiation complexes. Moreover, poly(A) added in trans inhibits translation from capped poly(A)+ mRNAs, but stimulates translation from capped poly(A)- mRNAs. We suggest that poly(A) is the formal equivalent of a transcriptional enhancer, i.e., that poly(A)-binding protein (PABP) bound at the 3\u27-end of mRNA may facilitate the binding of an initiation factor or ribosomal subunit at the mRNA 5\u27-end

A stochastic infilling algorithm for spatial-temporal rainfall data : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Statistics at Massey University

CD unreadableThe purpose of this thesis is to develop an infilling algorithm for 24-hour (daily) rainfall data. An infilling algorithm replaces missing data within the historical records with sensible estimates, where any appropriate method (prediction from a fitted model, interpolation between points, or random sampling) could be used to select and/or produce the required estimates. The algorithm developed uses simulation data generated using a stochastic point-process model which has been fitted to historical data. In this thesis, the spatial-temporal Neyman-Scott rectangular pulse model as presented in Cowpertwait et al. (2002) is fitted to data provided by Thames Water from 23 sites in the Thames Valley (UK). The model is shown to fit the data reasonably well; however it fails to fit the proportion of dry sites (which is not used in the fitting process). Nevertheless, simulated data is generated using the model and an infilling algorithm is derived. The algorithm is tested by replacing valid historical data with missing values, infilling these missing values, and then comparing relevant statistics for the two samples. Three algorithms are developed in this thesis, of which the final algorithm maintains the statistical characteristics of the historical data, including the proportion of dry sites, while infilling values that are similar to the known historical record

Why Don't Women Patent?

We investigate women's underrepresentation among holders of commercialized patents: only 5.5% of holders of such patents are female. Using the National Survey of College Graduates 2003, we find only 7% of the gap is accounted for by women's lower probability of holding any science or engineering degree, because women with such a degree are scarcely more likely to patent than women without. Differences among those without a science or engineering degree account for 15%, while 78% is accounted for by differences among those with a science or engineering degree. For the latter group, we find that women's underrepresentation in engineering and in jobs involving development and design explain much of the gap; closing it would increase U.S. GDP per capita by 2.7%.

Giant pop-ins and amorphization in germanium during indentation

Sudden excursions of unusually large magnitude (>1 μm), “giant pop-ins,” have been observed in the force-displacement curve for high load indentation of crystalline germanium(Ge). A range of techniques including Raman microspectroscopy, focused ion-beam cross sectioning, and transmission electron microscopy, are applied to study this phenomenon. Amorphous material is observed in residual indents following the giant pop-in. The giant pop-in is shown to be a material removal event, triggered by the development of shallow lateral cracks adjacent to the indent. Enhanced depth recovery, or “elbowing,” observed in the force-displacement curve following the giant pop-in is explained in terms of a compliant response of plates of material around the indent detached by lateral cracking. The possible causes of amorphization are discussed, and the implications in light of earlier indentation studies of Ge are considered

Essays on Government Policy in Real Estate Markets

This dissertation uses administrative data to study regulatory issues in the American real estate market. The first chapter studies spillovers from home foreclosures in Cook County, Illinois. Random assignment of foreclosure cases to judges allows for estimation of the causal effect of foreclosure (relative to a foreclosure case being dismissed) on neighboring foreclosure filings and housing transactions. When a property forecloses, the local housing market is disrupted--prices fall and more lower quality homes sell--and neighbors are more likely to end up in default and going through the foreclosure process. The second chapter examines how discontinuously applied transfer taxes distort the mar- ket for real estate sales in New York and New Jersey. These transfer taxes distort not only the price of real estate transactions that occur near the discontinuity, corresponding to sellers bearing the entire incidence of the tax, but also the volume of sales that occur--productive transactions that would occur if the tax were not discontinuous disappear from the market. The third and final chapter estimates the market-level response of home equity loans to two discontinuous mortgage policies--the home mortgage interest deduction, and real estate appraisal regulations in the Financial Institutions Reform Recovery and Enforcement Act. The estimates therein imply that home equity debt is very responsive to both the after-tax interest rate as well as lender underwriting requirements

Timing of the reproductive cycle of waved whelk, Buccinum undatum, on the US Mid-Atlantic Bight

Development of the unmanaged waved whelk (Buccinum undatum) fishery on the Mid-Atlantic continental shelf of the United States has initiated investigation into fisheries-related biological and population attributes of the species in this region. Maturation and reproduction timing vary by location for this species and are likely linked to bottom water temperature. This study examined the seasonal fluctuations in relevant body metrics and gonadosomatic index in relation to bottom temperature to assess the timing of the reproductive cycle of the B. undatum population in the southern-most extent of this species\u27 range in the Atlantic. To characterize variation over the maturation schedule, nine locations in the Mid-Atlantic Bight (MAB) were sampled five times between January 2017 and September 2017. Maturity was assessed macroscopically, with morphological methods, and via gonadosomatic indices. Male behavioral maturity estimates, based on a penis length to shell length index (PL50), were compared to estimates made using other methods for assessing maturity to test the efficacy of this commonly used ratio. Mature whelk were found in all months and peak reproductive activity was observed in spring and early summer. This timing suggests that ideal sampling to visually identify maturity to estimate size of maturity would be late winter or early spring. Unique oceanographic dynamics in the MAB, such as strong seasonal stratification results in large changes in annual bottom temperature which appears to be closely linked to the reproductive cycle in this region. Our data suggest that B. undatum in the MAB experience spawning and development at similar to 7-8 degrees C; temperatures warmer than Canadian populations and cooler than some UK conspecifics. To our knowledge, this is the first study to document the annual reproductive cycle of waved whelk in the United States

Looking for Cancer Clues in Publicly Accessible Databases

What started out as a mere attempt to tentatively identify proteins in experimental cancer-related 2D-PAGE maps developed into VIRTUAL2D, a web-accessible repository for theoretical pI/MW charts for 92 organisms. Using publicly available expression data, we developed a collection of tissue-specific plots based on differential gene expression between normal and diseased states. We use this comparative cancer proteomics knowledge base, known as the tissue molecular anatomy project (TMAP), to uncover threads of cancer markers common to several types of cancer and to relate this information to established biological pathways

Indentation-Induced Damage Mechanisms in Germanium

The response of crystalline Ge to indentation has been studied over a range of maximum loads. At a certain load, an unusual 'giant pop-in' event occurs, in which a discontinuous extension of >1 μm is observed in the force-displacement curve. In such cas