Use of Molecular Genetic Engineering in the Study of Animal Parasites and Their Vectors

Molecular genetics coupled with advances in immunology and parasite culture has become a powerful tool to study animal parasites and their vectors. Recombinant DNA techniques allow one to identify individual genes of DNA probes, amplify the nucleic acid of interest, and use this material to study: the role of the gene product in the biology of the organism; the evolution of parasites and their hosts; heterogeneity between species and within species; taxonomy and develop refined taxonomic tools; the immunology and biochemistry of host-parasite interactions; identification of specific cells or tissues that produce gene products; cytogenetics and localization of genes on chromosome in the study of animal parasites and their vectors will be presented

Molecular Approach to the Study of Trematode Parasites : the Blood Fluke

One important aspect of reproductive development in trematode parasites is the formation of a hardened eggshell which allows the zygote to develop into a miracidium in a hostile environment. The miracidium then can transfer the germline from the vertebrate host to snail intermediate host. Schistosome parasites, unlike other trematodes, have separate sexes and female reproductive development is known to depend on the presence of a male parasite. These facts make the blood flukes ideal material to study the mechanisms that underlie female reproductive development and eggshell formatian. We reasoned that the morphological and biochemical differences between the male and female must be reflected at the molecular level in the differential expression of sexually regulated genes. Radioactive single stranded cDNA was first transcribed from female RNA; and then sequences common to both male and female were removed by hybridization to an excess of male RNA. This probe was used to screen a cDNA library made from mRNA of adult worm paris. One hybridizing clone, pSMf 61-46, was shown to correspond to a 0.9 kilobase mRNA that is present only in mature female worms and is not detectable in female schistosomes from single-sex infections, in male worms or in eggs. Thus expression of the gene was female-specific. During normal bisexual infection this mRNA is first detected 28 days after infection (the time of worm pairing) and increases to a high level at 35 days postinfection, coinciding with egg production. Thus the temporal expression of the gene was dependent on paining with male worm. The nucleotide sequence of the gene shows an open reading frame that encodes a 16 kDA polypeptide that shows strong homology with eggshell proteins on insects. A second female-specific cDNA clone, F-4, represents a 1.6 kilobase mRNA whose expression is also correlated with worm pairing and subsequent egg production, encodes a different putative eggshell component of 44 kDA. The amino acid composition of the 16 kDA and 44 kDA polypeptides show a strong correlation with the actual amino acid composition of the schistosome eggshell. Thus these two polypeptides appear to the major components of the schistosome eggshell. Analysis of the genomic arrangement of the eggshell genes show that pl6 is represented by 5 gene copies and p48 is represented by 2-5 copies. The eggshell genes are expressed in the vitelline cell as recently demonstrated by in hybridization and immunocytochemical localization. The eggshell genes are being expressed in bacteria. The gene products will be used to study the biochemistry of eggshell formation

Anisotropic Magnification Distortion of the 3D Galaxy Correlation: II. Fourier and Redshift Space

In paper I of this series we discuss how magnification bias distorts the 3D correlation function by enhancing the observed correlation in the line-of-sight (LOS) orientation, especially on large scales. This lensing anisotropy is distinctive, making it possible to separately measure the galaxy-galaxy, galaxy-magnification {\it and} magnification-magnification correlations. Here we extend the discussion to the power spectrum and also to redshift space. In real space, pairs oriented close to the LOS direction are not protected against nonlinearity even if the pair separation is large; this is because nonlinear fluctuations can enter through gravitational lensing at a small transverse separation (or i.e. impact parameter). The situation in Fourier space is different: by focusing on a small wavenumber $k$, as is usually done, linearity is guaranteed because both the LOS and transverse wavenumbers must be small. This is why magnification distortion of the galaxy correlation appears less severe in Fourier space. Nonetheless, the effect is non-negligible, especially for the transverse Fourier modes, and should be taken into account in interpreting precision measurements of the galaxy power spectrum, for instance those that focus on the baryon oscillations. The lensing induced anisotropy of the power spectrum has a shape that is distinct from the more well known redshift space anisotropies due to peculiar motions and the Alcock-Paczynski effect. The lensing anisotropy is highly localized in Fourier space while redshift space distortions are more spread out. This means that one could separate the magnification bias component in real observations, implying that potentially it is possible to perform a gravitational lensing measurement without measuring galaxy shapes.Comment: 14 pages, minor revisions, as accepted for publication in Physical Review

Applying Linear Algebra in Solving the Lights Out Puzzle through Programming in Sage

The Lights Out puzzle presents an interesting problem in mathematics, encompassing elements of linear algebra, number theory and programming. This paper will analyze the mathematics associated with a version of the Lights Out puzzle game developed by Tiger Electronics (c.1995) that is most often presented to users. Our goal is to implement Sage using an algorithm in linear algebra to solve a linear system derived from this game. We attained results regarding the solvability and the structure of the solution space to the linear system. Furthermore, we used Sage to investigate other models of Lights Out puzzles in different settings, such as modifying the shape of the game’s array and adding more states of display other than ‘on’ or ‘off’

Scanning electron microscope observations on the miracidium of Schistosoma

Miracidia of two species of Schistosoma, viz. haematobium and japonicum, were studied with the scanning electron microscope to more clearly visualize what is seen with the light microscope and the transmission electron microscope, and more specifically, to relate the structure of the apical papilla to its function in snail penetration.The apical papilla of schistosome miracidia is composed of corrugated areas which form tiny suckerlike cups, presumably used by the miracidium to facilitate attachment to the snail during penetration. A lateral opening (secretory pore) on the apical papilla and short stubby apical cilia (tactile or sensory) are also demonstrated.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22128/1/0000555.pd

Lensing Corrections to Features in the Angular Two-Point Correlation Function and Power Spectrum

It is well known that magnification bias, the modulation of galaxy or quasar source counts by gravitational lensing, can change the observed angular correlation function. We investigate magnification-induced changes to the shape of the observed correlation function w(\theta) and the angular power spectrum C_{\ell}, paying special attention to the matter-radiation equality peak and the baryon wiggles. Lensing mixes the correlation function of the source galaxies with the matter correlation at the lower redshifts of the lenses. Since the lenses probe structure nearer to the observer, the angular scale dependence of the lensing terms is different from that of the sources, thus the observed correlation function is distorted. We quantify how the lensing corrections depend on the width of the selection function, the galaxy bias b, and the number count slope s. The correction increases with redshift and larger corrections are present for sources with steep number count slopes and/or broad redshift distributions. The most drastic changes to C_{\ell} occur for measurements at z >~1.5 and \ell <~ 100. For the source distributions we consider, magnification bias can shift the matter-radiation equality scale by 1-6% at z ~ 1.5 and by z ~ 3.5 the shift can be as large as 30%. The baryon bump in \theta^2w(\theta) is shifted by <~ 1% and the width is typically increased by ~10%. Shifts of >~ 0.5% and broadening of >~ 20% occur only for very broad selection functions and/or galaxies with (5s-2)/b>~2. However, near the baryon bump the magnification correction is not constant but a gently varying function which depends on the source population. Depending on how the w(\theta) data is fitted, this correction may need to be accounted for when using the baryon acoustic scale for precision cosmology.Comment: v2: 8 pages, 5 figures, text and figures condensed, references adde

Gravitational Lensing as Signal and Noise in Lyman-alpha Forest Measurements

In Lyman-alpha forest measurements it is generally assumed that quasars are mere background light sources which are uncorrelated with the forest. Gravitational lensing of the quasars violates this assumption. This effect leads to a measurement bias, but more interestingly it provides a valuable signal. The lensing signal can be extracted by correlating quasar magnitudes with the flux power spectrum and with the flux decrement. These correlations will be challenging to measure but their detection provides a direct measure of how features in the Lyman-alpha forest trace the underlying mass density field. Observing them will test the fundamental hypothesis that fluctuations in the forest are predominantly driven by fluctuations in mass, rather than in the ionizing background, helium reionization or winds. We discuss ways to disentangle the lensing signal from other sources of such correlations, including dust, continuum and background residuals. The lensing-induced measurement bias arises from sample selection: one preferentially collects spectra of magnified quasars which are behind overdense regions. This measurement bias is ~0.1-1% for the flux power spectrum, optical depth and the flux probability distribution. Since the effect is systematic, quantities such as the amplitude of the flux power spectrum averaged across scales should be interpreted with care.Comment: 22 pages, 8 figures; v2: references added, discussion expanded, matches PRD accepted versio

Excursion Sets and Non-Gaussian Void Statistics

Primordial non-Gaussianity (NG) affects the large scale structure (LSS) of the universe by leaving an imprint on the distribution of matter at late times. Much attention has been focused on using the distribution of collapsed objects (i.e. dark matter halos and the galaxies and galaxy clusters that reside in them) to probe primordial NG. An equally interesting and complementary probe however is the abundance of extended underdense regions or voids in the LSS. The calculation of the abundance of voids using the excursion set formalism in the presence of primordial NG is subject to the same technical issues as the one for halos, which were discussed e.g. in arXiv:1005.1203. However, unlike the excursion set problem for halos which involved random walks in the presence of one barrier $\delta_c$, the void excursion set problem involves two barriers $\delta_v$ and $\delta_c$. This leads to a new complication introduced by what is called the "void-in-cloud" effect discussed in the literature, which is unique to the case of voids. We explore a path integral approach which allows us to carefully account for all these issues, leading to a rigorous derivation of the effects of primordial NG on void abundances. The void-in-cloud issue in particular makes the calculation conceptually rather different from the one for halos. However, we show that its final effect can be described by a simple yet accurate approximation. Our final void abundance function is valid on larger scales than the expressions of other authors, while being broadly in agreement with those expressions on smaller scales.Comment: 28 pages (18+appendices), 7 figures; v2 -- minor changes in sec 3.2, version published in PR

Local stochastic non-Gaussianity and N-body simulations

Large-scale clustering of highly biased tracers of large-scale structure has emerged as one of the best observational probes of primordial non-Gaussianity of the local type (i.e. f_{NL}^{local}). This type of non-Gaussianity can be generated in multifield models of inflation such as the curvaton model. Recently, Tseliakhovich, Hirata, and Slosar showed that the clustering statistics depend qualitatively on the ratio of inflaton to curvaton power \xi after reheating, a free parameter of the model. If \xi is significantly different from zero, so that the inflaton makes a non-negligible contribution to the primordial adiabatic curvature, then the peak-background split ansatz predicts that the halo bias will be stochastic on large scales. In this paper, we test this prediction in N-body simulations. We find that large-scale stochasticity is generated, in qualitative agreement with the prediction, but that the level of stochasticity is overpredicted by ~30%. Other predictions, such as \xi independence of the halo bias, are confirmed by the simulations. Surprisingly, even in the Gaussian case we do not find that halo model predictions for stochasticity agree consistently with simulations, suggesting that semi-analytic modeling of stochasticity is generally more difficult than modeling halo bias.Comment: v3: minor changes matching published versio

2011-2012 Evening of the Arts featuring Lynn Philharmonia Orchestra

Program: Academic Festival Overture, op. 80 / Johannes Brahms Lincoln Portrait / Aaron Copland Robert Watson, narrator Over the Rainbow from the Wizard of Oz / Harold Arlen Katie Lemmon, vocalist Think of Me from the Phantom of the Opera / Andrew Lloyd Webber Stephanie Loverde, vocalist We Are Women from Candide / Leonard Bernstein Katie Lemmon, vocalist Stephanie Loverde, vocalist Concerto for Violin and Orchestra, op. 35 / Pyotr Ilyich Tchaikovsky Sylvia Kim, violinhttps://spiral.lynn.edu/conservatory_philharmonia/1105/thumbnail.jp