2,683 research outputs found
A New Isozyme Marker for the Short Arm of Chromosome 6
Wendel et al. (MNL 60:109-110) reported isozyme segregation data that suggested Adkl (adenylate kinase) is located near the centromere on chromosome 6, and tentatively proposed a location on 6S. Subsequent work has confirmed that Adkl is on 6S, which is significant in that this is one of the most poorly mapped chromosome arms of maize
New Isozyme Systems for Maize (Zea mays L.): Aconitate Hydratase, Adenylate Kinase, NADH Dehydrogenase, and Shikimate Dehydrogenase
Electrophoretic variation and inheritance of four novel enzyme systems were studied in maize (Zea mays L.). A minimum of 10 genetic loci collectively encodes isozymes of aconitate hydratase (ACO; EC 4.2.1.3.), adenylate kinase (ADK; EC 2.7.4.3), NADH dehydrogenase (DIA; EC 1.6.99.-), and shikimate dehydrogenase (SAD; EC 1.1.1.25). At least four loci are responsible for the genetic control of ACO. Genetic data for two of the encoding loci, Aco1 and Aco4, demonstrated that at least two maize ACOs are active as monomers. Analysis of organellar preparations suggests that ACO1 and ACO4 are localized in the cytosolic and mitochondrial subcellular fractions, respectively. Maize ADK is encoded by a single nuclear locus, Adk1, governing monomeric enzymes that are located in the chloroplasts. Two cytosolic and two mitochondrial forms of DIA were electrophoretically resolved. Segregation analyses demonstrated that the two cytosolic isozymes are controlled by separate loci, Dia1 and Dia2, coding for products that are functional as monomers (DIA1) and dimers (DIA2). The major isozyme of SAD is apparently cytosolic, although an additional faintly staining plastid form may be present. Alleles at Sad1 are each associated with two bands that cosegregate in controlled crosses. Linkage analyses and crosses with B-A translocation stocks were effective in determining the map locations of six loci, including the previously described but unmapped locus Acp4. Several of these loci were localized to sparsely mapped regions of the genome. Dia2 and Acp4 were placed on the distal portion of the long arm of chromosome 1, 12.6 map units apart. Dia1 was localized to chromosome 2, 22.2 centimorgans (cM) from B1. Aco1 was mapped to chromosome 4, 6.2 cM from su1. Adk1 was placed on the poorly marked short arm of chromosome 6, 8.1 map units from rgd1. Less than 1% recombination was observed between Glu1 (on chromosome 10) and Sad1. In contrast to many other maize isozyme systems, there was little evidence of gene duplication or of parallel linkage relationships for these allozyme loci
Confidentiality and public protection: ethical dilemmas in qualitative research with adult male sex offenders
This paper considers the ethical tensions present when engaging in in-depth interviews with convicted sex offenders. Many of the issues described below are similar to those found in other sensitive areas of research. However, confidentiality and public protection are matters that require detailed consideration when the desire to know more about men who have committed serious and harmful offences is set against the possibility of a researcher not disclosing previously unknown sensitive information that relates to the risk of someone being harmed.</p
Contrasting Controls on Microzooplankton Grazing and Viral Infection of Microbial Prey
The encounter and capture of bacteria and phytoplankton by microbial predators and parasites is fundamental to marine ecosystem organization and activity. Here, we combined classic biophysical models with published laboratory measurements to infer functional traits, including encounter kernel and capture efficiency, for a wide range of marine viruses and microzooplankton grazers. Despite virus particles being orders of magnitude smaller than microzooplankton grazers, virus encounter kernels and adsorption rates were in many cases comparable in magnitude to grazer encounter kernel and clearance, pointing to Brownian motion as a highly effective method of transport for viruses. Inferred virus adsorption efficiency covered many orders of magnitude, but the median virus adsorption efficiency was between 5 and 25% depending on the assumed host swimming speed. Uncertainty on predator detection area and swimming speed prevented robust inference of grazer capture efficiency, but sensitivity analysis was used to identify bounds on unconstrained processes. These results provide a common functional trait framework for understanding marine host-virus and predator-prey interactions, and highlight the value of theory for interpreting measured life-history traits
Effects of pH_2O, pH_2 and fO_2 on the diffusion of h-bearing species in lunar basaltic liquid and an iron-free basaltic analog at 1 atm
We have experimentally determined the diffusivity of water in a representative lunar basaltic liquid composition (LG) and in an iron-free analog of a basaltic liquid (AD) at the low water concentrations and low oxygen fugacities (fO_2) relevant to the eruption of lunar basalts. Experiments were conducted at 1 atm and 1350 °C over a range of pH_2/pH_2O from near zero to ∼10 and a range in fO_2 spanning ∼9 orders of magnitude (from 2.2 log units below the iron-wüstite buffer, IW–2.2, to IW+6.7). The water concentrations measured in our quenched experimental glasses by secondary ion mass spectrometry (SIMS) and Fourier transform infrared spectroscopy (FTIR) vary from a few ppm to ∼430 ppm. Water concentration gradients in the majority of our AD experiments are well described by models in which the diffusivity of water (D*_(water)) has a constant value of ∼2×10^(–10) m^2/s, while our LG results indicate that D*_(water) in LG melt has a constant value of ∼6×10^(–10) m^2/s under the conditions of our experiments. Water concentration gradients in hydration and dehydration experiments that were run simultaneously in H_2/CO_2 gas mixtures are well described by the same D*_(water), and water concentrations measured near the melt-vapor interfaces of these experiment pairs are approximately the same. These observations strongly support an equilibrium boundary condition for our experiments containing >70 ppm H_2O. However, dehydration experiments into nominally anhydrous CO_2, N_2, and CO/CO_2 gas mixtures leave some scope for the importance of kinetics during dehydration of melts containing less than a few 10’s of ppm H_2O. Comparison of our results with the modified speciation model (Ni et al., 2013) in which both molecular water and hydroxyl are allowed to diffuse suggests that we have resolved the diffusivity of hydroxyl (D_(OH)) in AD and LG melts. Our results support a positive correlation between D_(OH) and melt depolymerization. Best-fit values of D*_(water) for our LG experiments vary within a factor of ∼2 over a range of pH_2/pH_2O from 0.007 to 9.7 and a range of logf O_2 from IW–2.2 to IW+4.9. The relative insensitivity of our best-fit values of D*_(water) to variations in pH_2 suggests that H_2 diffusion did not control the rate of degassing of H-bearing species from the lunar glasses of Saal et al. (2008); however, we cannot rule out a role for molecular H2 diffusion under lower-temperature and/or higher-pressure conditions than explored in our experiments. The value of D*_(water) chosen by Saal et al. (2008) for modeling the diffusive degassing of the lunar volcanic glasses is within a factor of ∼2 of our measured value in LG melt at 1350 °C. By coupling our LG results at 1350 °C with an activation energy of 220 kJ/mol (Zhang et al. 2017), we obtain the following Arrhenius relationship, which can be used to model syneruptive diffusive water loss from lunar melt beads:
D*_(water)(m^2/s) = 7.2×10^(-3)exp(-2.6×10^4/T(K))
Media coverage and public understanding of sentencing policy in relation to crimes against children
This research examines how the media report on sentences given to those who commit serious crimes against children and how this impacts on public knowledge and attitudes. Three months of press and television coverage were analysed in order to establish the editorial lines that are taken in different sections of the media and how they are promoted by selective reporting of sentencing. Results indicate that a small number of very high profile crimes account for a significant proportion of reporting in this area and often, particularly in the tabloid press, important information regarding sentencing rationale is sidelined in favour of moral condemnation and criticism of the judiciary. Polling data indicate that public attitudes are highly critical of sentencing but also confused about the meaning of tariffs. The article concludes by discussing what can be done to promote a more informed public debate over penal policy in this area
Robotic Extrusion of Algae-Laden Hydrogels for Large-Scale Applications
A bioprinting technique for large‐scale, custom‐printed immobilization of microalgae is developed for potential applications within architecture and the built environment. Alginate‐based hydrogels with various rheology modifying polymers and varying water percentages are characterized to establish a window of operation suitable for layer‐by‐layer deposition on a large scale. Hydrogels formulated with methylcellulose and carrageenan, with water percentages ranging from 80% to 92.5%, demonstrate a dominant viscoelastic solid–like property with G′ > G″ and a low phase angle, making them the most suitable for extrusion‐based printing. A custom multimaterial pneumatic extrusion system is developed to be attached on the end effector of an industrial multiaxis robot arm, allowing precision‐based numerically controlled layered deposition of the viscous hydrogel. The relationship between the various printing parameters, namely air pressure, material viscosity, viscoelasticity, feed rate, printing distance, nozzle diameter, and the speed of printing, are characterized to achieve the desired resolution of the component. Printed prototypes are postcured in CaCl2 via crosslinking. Biocompatibility tests show that cells can survive for 21 days after printing the constructs. To demonstrate the methodology for scale‐up, a 1000 × 500 mm fibrous hydrogel panel is additively deposited with 3 different hydrogels with varying water percentages
Managing the Socially Marginalized: Attitudes Towards Welfare, Punishment and Race
Welfare and incarceration policies have converged to form a system of governance over socially marginalized groups, particularly racial minorities. In both of these policy areas, rehabilitative and social support objectives have been replaced with a more punitive and restrictive system. The authors examine the convergence in individual-level attitudes concerning welfare and criminal punishment, using national survey data. The authors\u27 analysis indicates a statistically significant relationship between punitive attitudes toward welfare and punishment. Furthermore, accounting for the respondents\u27 racial attitudes explains the bivariate relationship between welfare and punishment. Thus, racial attitudes seemingly link support for punitive approaches to opposition to welfare expenditures. The authors discuss the implications of this study for welfare and crime control policies by way of the conclusion
Cities in fiction: Perambulations with John Berger
This paper explores selected novels by John Berger in which cities play a central role. These cities are places, partially real and partially imagined, where memory, hope, and despair intersect. My reading of the novels enables me to trace important themes in recent discourses on the nature of contemporary capitalism, including notions of resistance and universality. I also show how Berger?s work points to a writing that can break free from the curious capacity of capitalism to absorb and feed of its critique
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