Mutations in Drosophila Greatwall/Scant Reveal Its Roles in Mitosis and Meiosis and Interdependence with Polo Kinase

Polo is a conserved kinase that coordinates many events of mitosis and meiosis, but how it is regulated remains unclear. Drosophila females having only one wild-type allele of the polo kinase gene and the dominant Scant mutation produce embryos in which one of the centrosomes detaches from the nuclear envelope in late prophase. We show that Scant creates a hyperactive form of Greatwall (Gwl) with altered specificity in vitro, another protein kinase recently implicated in mitotic entry in Drosophila and Xenopus. Excess Gwl activity in embryos causes developmental failure that can be rescued by increasing maternal Polo dosage, indicating that coordination between the two mitotic kinases is crucial for mitotic progression. Revertant alleles of Scant that restore fertility to polo–Scant heterozygous females are recessive alleles or deficiencies of gwl; they show chromatin condensation defects and anaphase bridges in larval neuroblasts. One recessive mutant allele specifically disrupts a Gwl isoform strongly expressed during vitellogenesis. Females hemizygous for this allele are sterile, and their oocytes fail to arrest in metaphase I of meiosis; both homologues and sister chromatids separate on elongated meiotic spindles with little or no segregation. This allelic series of gwl mutants highlights the multiple roles of Gwl in both mitotic and meiotic progression. Our results indicate that Gwl activity antagonizes Polo and thus identify an important regulatory interaction of the cell cycle

Jet Investigations Using the Radial Moment

We define the radial moment, , for jets produced in hadron-hadron collisions. It can be used as a tool for studying, as a function of the jet transverse energy and pseudorapidity, radiation within the jet and the quality of a perturbative description of the jet shape. We also discuss how non-perturbative corrections to the jet transverse energy affect .Comment: 14 pages, LaTeX, 6 figure

The SFA Economist Vol. 2 No. 2

https://scholarworks.sfasu.edu/economist/1003/thumbnail.jp

The Influence of Land Use on Aquatic Macroinvertebrates in Streams and Rivers of South Carolina

2008 S.C. Water Resources Conference - Addressing Water Challenges Facing the State and Regio

Capturing coastal water clarity variability with Landsat 8

© The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Luis, K. M. A., Rheuban, J. E., Kavanaugh, M. T., Glover, D. M., Wei, J., Lee, Z., & Doney, S. C. Capturing coastal water clarity variability with Landsat 8. Marine Pollution Bulletin, 145, (2019): 96-104, doi: 10.1016/j.marpolbul.2019.04.078.Coastal water clarity varies at high temporal and spatial scales due to weather, climate, and human activity along coastlines. Systematic observations are crucial to assessing the impact of water clarity change on aquatic habitats. In this study, Secchi disk depths (ZSD) from Boston Harbor, Buzzards Bay, Cape Cod Bay, and Narragansett Bay water quality monitoring organizations were compiled to validate ZSD derived from Landsat 8 (L8) imagery, and to generate high spatial resolution ZSD maps. From 58 L8 images, acceptable agreement was found between in situ and L8 ZSD in Buzzards Bay (N = 42, RMSE = 0.96 m, MAPD = 28%), Cape Cod Bay (N = 11, RMSE = 0.62 m, MAPD = 10%), and Narragansett Bay (N = 8, RMSE = 0.59 m, MAPD = 26%). This work demonstrates the value of merging in situ ZSD with high spatial resolution remote sensing estimates for improved coastal water quality monitoring.This work was supported by the John D. and Catherine T. MacArthur Foundation (grant 14-106159-000-CFP) and by the National Science Foundation grant DGE 1249946, Integrative Graduate Education and Research Traineeship (IGERT): Coasts and Communities – Natural and Human Systems in Urbanizing Environments. Lastly, we are indebted to the Massachusetts Water Resources Authority, Buzzards Bay Coalition, Provincetown Center for Coastal Studies, Narragansett Bay Commission, and the numerous citizen scientists responsible for collecting the in situ measurements used in this study. Comments and suggestions from our anonymous reviewer were greatly appreciated

Is the molecular KS relationship universal down to low metallicities?

Funding: . RJS gratefully acknowledges an STFC Ernest Rutherford fellowship (grant ST/N00485X/1). SCOG, RT, MCS, and RSK acknowledge funding from the European Research Council via the ERC Synergy Grant ‘ECOGAL – Understanding our Galactic ecosystem: From the disc of the Milky Way to the formation sites of stars and planets (project ID 855130).In recent years, it has been speculated that in extreme low-metallicity galactic environments, stars form in regions that lack H2. In this paper, we investigate how changing the metallicity and ultraviolet (UV) field strength of a galaxy affects the star formation within, and the molecular gas Kennicutt–Schmidt (KS) relation. Using extremely high-resolution AREPO simulations of isolated dwarf galaxies, we independently vary the metallicity and UV field to between 1 per cent and 10 per cent solar neighbourhood values. We include a non-equilibrium, time-dependent chemical network to model the molecular composition of the interstellar medium and include the effects of gas shielding from an ambient UV field. Crucially, our simulations directly model the gravitational collapse of gas into star-forming clumps and cores and their subsequent accretion using sink particles. In this first publication, we find that reducing the metallicity and UV field by a factor of 10 has no effect on star formation and minimal effect on the cold, dense star-forming gas. The cold gas depletion times are almost an order of magnitude longer than the molecular gas depletion time due to the presence of star formation in H I dominated cold gas. We study the H2 KS relationship that arises naturally within the simulations and find a near-linear power-law index of N = 1.09 ± 0.014 in our fiducial 10 per cent solar metallicity model. As the metallicity and UV field are reduced, this becomes moderately steeper, with a slope of N = 1.24 ± 0.022 for our 1 per cent solar metallicity and 1 per cent solar UV field model.Peer reviewe

A Field Study Using the Polymerase Chain Reaction (Pcr) to Screen for Brugia Microfilariae in Human and Animal Blood

Blood samples from 43 humans and 14 cats positive with Brugia microfilariae were analyzed in a field study in Tanjung Pinang, Indonesia. The study used the polymerase chain reaction (PCR) to compare the sensitivity of radioactive and biotinylated species-specific oligonuleotide probes. The cloning char­acterization of the Hha I repeat DNA family found in filarial parasites of the genus Brugia, and the development of species-specific probes for B.malayi and B.pahangi based on these repeats has been described elsewhere (PNAS USA 83: 797-801); Mol.Biochem. Parasitol. 2$: 163-170). The use of radioisotopes for labelling DNA probes is both expensive and inconvenient. To replace these probes, biotinylated DNA probes have been designed for non- radioactive detection of B.malayi and B.pahangi. These oligonucleotide probes have long tails of biotinylated uridine residues added to their 5\u27 end. As little as 100 pg of Brugia DNA can be detected on dot blot with these probes. Detection of the probes is based on an avidin-alkaline phosphatase colorimetric assay. In order to distinguish between infected from uninfected individuals, it is necessary to detect the amount of DNA in one microfilaria (about 60 pg). The polymerase chain reaction (PCR) is a procedure in which a small amount of DNA can be amplified up to 1 million-fold. A part of each sample in this study was PCR amplified and compared with the unamplified portion using both the radioactive and biotinylated DNA probe. The PCR amplified samples were accurately identified by both the radioactive and biotinylated B.malayi and B.pahangi probes. Even samples with as few as two microfilariae per lOOul of blood were easily detected. The samples that were not PCR amplified were accurately identified after only long exposures (greater than one week) to the radioactive probes. The biotinylated probes, were not sensitive enough for accurate identification of the non-PCR amplified samples. The polymerase chain reaction is, therefore, a promising new tool for enhancing the sensitivity of parasite detection assays based on DNA probes. This will be especially important in designing assay based on non-radioactive DNA probes

Two-Loop g -> gg Splitting Amplitudes in QCD

Splitting amplitudes are universal functions governing the collinear behavior of scattering amplitudes for massless particles. We compute the two-loop g -> gg splitting amplitudes in QCD, N=1, and N=4 super-Yang-Mills theories, which describe the limits of two-loop n-point amplitudes where two gluon momenta become parallel. They also represent an ingredient in a direct x-space computation of DGLAP evolution kernels at next-to-next-to-leading order. To obtain the splitting amplitudes, we use the unitarity sewing method. In contrast to the usual light-cone gauge treatment, our calculation does not rely on the principal-value or Mandelstam-Leibbrandt prescriptions, even though the loop integrals contain some of the denominators typically encountered in light-cone gauge. We reduce the integrals to a set of 13 master integrals using integration-by-parts and Lorentz invariance identities. The master integrals are computed with the aid of differential equations in the splitting momentum fraction z. The epsilon-poles of the splitting amplitudes are consistent with a formula due to Catani for the infrared singularities of two-loop scattering amplitudes. This consistency essentially provides an inductive proof of Catani's formula, as well as an ansatz for previously-unknown 1/epsilon pole terms having non-trivial color structure. Finite terms in the splitting amplitudes determine the collinear behavior of finite remainders in this formula.Comment: 100 pages, 33 figures. Added remarks about leading-transcendentality argument of hep-th/0404092, and additional explanation of cut-reconstruction uniquenes

One-Loop Corrections to Two-Quark Three-Gluon Amplitudes

We present the one-loop QCD amplitudes for two external massless quarks and three external gluons ($\bar{q}qggg$). This completes the set of one-loop amplitudes needed for the next-to-leading-order corrections to three-jet production at hadron colliders. We also discuss how to use group theory and supersymmetry to minimize the amount of calculation required for the more general case of one-loop two-quark $n$-gluon amplitudes. We use collinear limits to provide a stringent check on the amplitudes.Comment: plain Tex, 46 pages with 13 figures in a uuencoded file, corrected case j=1 of eq. (IV.7), and signs in eq. (4.9