AN EVALUATION OF THE BARRNETT AND SELIGMAN PROCEDURE WHEN USED TO DETERMINE CHANGES IN THE RATIO OF NUCLEAR PROTEIN-BOUND DISULFIDE TO SULFHYDRYL GROUPS DURING MITOSIS

Using a modification of the Barrnett and Seligman histochemical procedure, the proportion of protein-bound S—S/SH Was measured in the chromatin of onion root tip cells at three different stages of mitosis as well as in the nucleolus. Inconsistencies between experiments led to studies of the nature of the histochemical reaction before and after sections were reduced in thioglycolate. Different fixatives and ribonuclease were tested for their effects on the outcome of the reaction.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Dusty plasma cavities: probe-induced and natural

A comprehensive exploration of regional dust evacuation in complex plasma crystals is presented. Voids created in 3D crystals on the International Space Station have provided a rich foundation for experiments, but cavities in dust crystals formed in ground-based experiments have not received as much attention. Inside a modified GEC RF cell, a powered vertical probe was used to clear the central area of a dust crystal, producing a cavity with high cylindrical symmetry. Cavities generated by three mechanisms are examined. First, repulsion of micrometer-sized particles by a negatively charged probe is investigated. A model of this effect developed for a DC plasma is modified and applied to explain new experimental data in RF plasma. Second, the formation of natural cavities is surveyed; a radial ion drag proposed to occur due to a curved sheath is considered in conjunction with thermophoresis and a flattened confinement potential above the center of the electrode. Finally, cavity formation unexpectedly occurs upon increasing the probe potential above the plasma floating potential. The cavities produced by these methods appear similar, but each are shown to be facilitated by fundamentally different processes.Comment: 10 pages, 12 figure

Selection bias in the M_BH-sigma and M_BH-L correlations and its consequences

It is common to estimate black hole abundances by using a measured correlation between black hole mass and another more easily measured observable such as the velocity dispersion or luminosity of the surrounding bulge. The correlation is used to transform the distribution of the observable into an estimate of the distribution of black hole masses. However, different observables provide different estimates: the Mbh-sigma relation predicts fewer massive black holes than does the Mbh-L relation. This is because the sigma-L relation in black hole samples currently available is inconsistent with that in the SDSS sample, from which the distributions of L or sigma are based: the black hole samples have smaller L for a given sigma or have larger sigma for a given L. This is true whether L is estimated in the optical or in the NIR. If this is a selection rather than physical effect, then the Mbh-sigma and Mbh-L relations currently in the literature are also biased from their true values. We provide a framework for describing the effect of this bias. We then combine it with a model of the bias to make an estimate of the true intrinsic relations. While we do not claim to have understood the source of the bias, our simple model is able to reproduce the observed trends. If we have correctly modeled the selection effect, then our analysis suggests that the bias in the relation is likely to be small, whereas the relation is biased towards predicting more massive black holes for a given luminosity. In addition, it is likely that the Mbh-L relation is entirely a consequence of more fundamental relations between Mbh and sigma, and between sigma and L. The intrinsic relation we find suggests that at fixed luminosity, older galaxies tend to host more massive black holes.Comment: 12 pages, 7 figures. Accepted by ApJ. We have added a figure showing that a similar bias is also seen in the K-band. A new appendix describes the BH samples as well as the fits used in the main tex

Rejection of the Impossibility Theorem for Theory X

The principal aims of population axiology are to increase the wellbeing of everyone, to prevent the suffering of future generations, and to make everyone more equal in these respects. A crisis in the pursuit of these goals came when Derek Parfit (1984) suggested that they inevitably result in a repugnant conclusion, that for any happy world, a miserable world of people whose lives were just barely worth living would be better, were it sufficiently populous. Since then, Gustaf Arrhenius (2000) has shown that these same principles also lead to a sadistic conclusion, that it can be better to add people with negative welfare rather than positive welfare when adding people without affecting the original people’s welfare. What is more, he showed that there is no welfarist axiology that satisfies these three principles and yet avoids the repugnant conclusion. He called this the impossibility theorem for Theory X. This essay maintains that the ninth premiss of the impossibility theorem contains an invalid inference, and therefore presents a disproof of the theorem

Measurement of net electric charge and dipole moment of dust aggregates in a complex plasma

Understanding the agglomeration of dust particles in complex plasmas requires a knowledge of the basic properties such as the net electrostatic charge and dipole moment of the dust. In this study, dust aggregates are formed from gold coated mono-disperse spherical melamine-formaldehyde monomers in a radio-frequency (rf) argon discharge plasma. The behavior of observed dust aggregates is analyzed both by studying the particle trajectories and by employing computer models examining 3D structures of aggregates and their interactions and rotations as induced by torques arising from their dipole moments. These allow the basic characteristics of the dust aggregates, such as the electrostatic charge and dipole moment, to be determined. It is shown that the experimental results support the predicted values from computer models for aggregates in these environments.Comment: 6 pages, 7 figure

Communication, Psychosocial, and Educational Outcomes of Children with Cochlear Implants and Challenges Remaining for Professionals and Parents

This paper provides an overview and a synthesis of the findings of a large, multifaceted study investigating outcomes from paediatric cochlear implantation. The study included children implanted at several Australian implant clinics and attending a variety of early intervention and educational settings across a range of locations in eastern Australia. It investigated three major aspects of childhood cochlear implantation: (1) parental expectations of their children's implantation, (2) families' decision-making processes, and (3) the communication, social, and educational outcomes of cochlear implantation for deaf children. It employed a mixed-methods approach in which quantitative survey data were gathered from 247 parents and 151 teachers, and qualitative data from semistructured interviews with 27 parents, 15 teachers, and 11 children and adolescents with cochlear implants. The summarised findings highlight several areas where challenges remain for implant clinics, parents, and educators if children with cochlear implants are to reach their full potential personally, educationally, and socially

A study of intense magnetic fields for high energy forming and structural assembly Interim report

Determination of maximum force on static sheet of aluminum subjected to magnetic field of hammer coi

Separation of Parallel Encoded Complex-Valued Slices (SPECS) From A Single Complex-Valued Aliased Coil Image

Purpose Achieving a reduction in scan time with minimal inter-slice signal leakage is one of the significant obstacles in parallel MR imaging. In fMRI, multiband-imaging techniques accelerate data acquisition by simultaneously magnetizing the spatial frequency spectrum of multiple slices. The SPECS model eliminates the consequential inter-slice signal leakage from the slice unaliasing, while maintaining an optimal reduction in scan time and activation statistics in fMRI studies. Materials and Methods When the combined k-space array is inverse Fourier reconstructed, the resulting aliased image is separated into the un-aliased slices through a least squares estimator. Without the additional spatial information from a phased array of receiver coils, slice separation in SPECS is accomplished with acquired aliased images in shifted FOV aliasing pattern, and a bootstrapping approach of incorporating reference calibration images in an orthogonal Hadamard pattern. Result The aliased slices are effectively separated with minimal expense to the spatial and temporal resolution. Functional activation is observed in the motor cortex, as the number of aliased slices is increased, in a bilateral finger tapping fMRI experiment. Conclusion The SPECS model incorporates calibration reference images together with coefficients of orthogonal polynomials into an un-aliasing estimator to achieve separated images, with virtually no residual artifacts and functional activation detection in separated images