Solo Voice Detection Via Optimal Cancellation

Automatically identifying sections of solo voices or instruments within a large corpus of music recordings would be useful, for example, to construct a library of isolated instruments to train signal models. We consider several ways to identify these sections, including a baseline classifier trained on conventional speech features. Our best results, achieving frame level precision and recall of around 70%, come from an approach that attempts to track the local periodicity of an assumed solo musical voice, then classifies the segment as a genuine solo or not on the basis of what proportion of the energy can be canceled by a comb filter constructed to remove just that periodicity

Lyman-alpha Emission from a Luminous z=8.68 Galaxy: Implications for Galaxies as Tracers of Cosmic Reionization

We report the discovery of Lyman-alpha emission (Ly$\alpha$) in the bright galaxy EGSY-2008532660 (hereafter EGSY8p7) using the MOSFIRE spectrograph at the Keck Observatory. First reported by Roberts-Borsani et al. (2015), it was selected for spectroscopic observations because of its photometric redshift ($z_{phot}=8.57^{+0.22}_{-0.43}$), apparent brightness (H$_{160}=25.26\pm0.09$) and red Spitzer/IRAC [3.6]-[4.5] color indicative of contamination by strong oxygen emission in the [4.5] band. With a total integration of $\sim$4.3 hours, our data reveal an emission line at $\simeq$11776 {\AA} which we argue is likely Ly$\alpha$ at a redshift $z_{spec}=8.683^{+0.001}_{-0.004}$, in good agreement with the photometric estimate. The line was detected independently on two nights using different slit orientations and its detection significance is $\sim7.5\sigma$. An overlapping skyline contributes significantly to the uncertainty on the total line flux although the significance of the detected line is robust to a variety of skyline-masking procedures. By direct addition and a Gaussian fit, we estimate a 95\% confidence range of 1.0--2.5$\times10^{-17}$ erg s$^{-1}$ cm$^{-2}$, corresponding to a rest-frame equivalent width of 17--42 {\AA}. EGSY8p7 is the most distant galaxy confirmed spectroscopically to date, and the third luminous source in the EGS field beyond $z_{phot}\gtrsim7.5$ with detectable Ly$\alpha$ emission viewed at a time when the intergalactic medium is believed to be fairly neutral. Although the reionization process was probably patchy, we discuss whether luminous sources with prominent IRAC color excesses may harbor harder ionizing spectra than the dominant fainter population thereby creating earlier ionized bubbles. Further spectroscopic follow-up of such bright sources promises important insight into the early formation of galaxies.Comment: V3: ApJL accepted; 7 pages, 4 figures, 1 tabl

How technology-mediated reflections shaped students’ conceptualisation of racism in a fully-online master’s program

Abstract: The study investigated how students’ learning about racism were shaped in their reflections during enrolment in a fully-online master’s program through the lens of Critical Race Theory (CRT). Students were enrolled for a module in the program ‘Learning Ecosystems B.’ The module is one of eight coursework modules in the program and was offered from 6 May 2019 to 23 June 2019. The module explicitly targets the manifestation of racism and sexism on social media. The module content and pedagogical design require students to critically engage educational theories, and specifically in this module, theories on racism and sexism, and to intersect those with how digital technologies and social media are used in society. Ninety-two students were enrolled for the module...M.Ed. (Information and Communication Technology in Education

Perturbative Corrections for Staggered Fermion Bilinears

We calculate the perturbative corrections to fermion bilinears that are used in numerical simulations when extracting weak matrix elements using staggered fermions. This extends previous calculations of Golterman and Smit, and Daniel and Sheard. In particular, we calculate the corrections for non-local bilinears defined in Landau gauge with gauge links excluded. We do this for the simplest operators, i.e. those defined on a $2^4$ hypercube, and for tree level improved operators which live on $4^4$ hypercubes. We also consider gauge invariant operators in which the ``tadpole'' contributions are suppressed by projecting the sums of products of gauge links back in to the gauge group. In all cases, we find that the variation in the size of the perturbative corrections is smaller than those with the gauge invariant unimproved operators. This is most strikingly true for the smeared operators. We investigate the efficacy of the mean-field method of Lepage and Mackenzie at summing up tadpole contributions. In a companion paper we apply these results to four-fermion operators.Comment: 29 pages latex, 4 postscript figures included, UW/PT-92-13 and CEBAF-TH-92-2

Level Crossing for Hot Sphalerons

We study the spectrum of the Dirac Hamiltonian in the presence of high temperature sphaleron-like fluctuations of the electroweak gauge and Higgs fields, relevant for the conditions prevailing in the early universe. The fluctuations are created by numerical lattice simulations. It is shown that a change in Chern-Simons number by one unit is accompanied by eigenvalues crossing zero and a change of sign of the generalized chirality \tGf= (-1)^{2T+1} \gf which labels these modes. This provides further evidence that the sphaleron-like configurations observed in lattice simulations may be viewed as representing continuum configurations.Comment: Latex file, 29 pages + 13 figure

'n Analise van die sosiale waardes in die leefwêreld van Klemens van Aleksandrië soos vergestalt in sy Paidagogos (Afrikaans)

Biblical scholars have grown increasingly aware of the importance of looking at texts not only in their historical or literary contexts, but also in their socio-cultural contexts. Many studies have shown that honour and shame were core social values in the ancient Mediterranean world. By scrutinizing the available research on the topic of honour and shame, one realizes that there were indeed four major social values in the Mediterranean world, that is i) honour and shame, ii) patronage and reciprocity, iii) kinship and iv) purity. Modern biblical scholars would often appeal to the works of the classical authors in order to show how important these values were in the ancient world. Unfortunately claims that are being made in modern studies concerning honour and shame are usually based on the biblical and classical writings. These scholars seldom consult patristic writings. In this study it is argued that the ancient Church Fathers were indeed aware of these social values. The four social values mentioned above are taken as a basis to unlock the social context of Clement of Alexandria’s Paedagogue. It illustrates the importance of understanding the core social values of the Mediterranean society in order to interpret the theology of the early Church Fathers.Thesis (DLitt (Greek))--University of Pretoria, 2008.Ancient Languagesunrestricte

Effect of helium pre- or postconditioning on signal transduction kinases in patients undergoing coronary artery bypass graft surgery

Background: The noble gas helium induces pre- and postconditioning in animals and humans. Volatile anesthetics induce cardioprotection in humans undergoing coronary artery bypass graft (CABG) surgery. We hypothesized that helium induces pre-and postconditioning in CABG-patients, affecting signaling molecules protein kinase C-epsilon (PKC-epsilon), p38 mitogen activated protein kinase (p38 MAPK), extracellular signal-regulated kinase 1/2 (ERK-1/2) and heat shock protein 27 (HSP-27) within cardiac tissue, and reducing postoperative troponin levels. Methods: After ethical approval and informed consent, 125 elective patients undergoing CABG surgery were randomised into this prospective, placebo controlled, investigator blinded, parallel arm single-centre study. Helium preconditioning (3 x 5 min of 70 % helium and 30 % oxygen) was applied before aortic cross clamping; postconditioning (15 min of helium) was applied before release of the aortic cross clamp. Signaling molecules were measured in right atrial appendix specimens. Troponin-T was measured at 4, 12, 24 and 48 h postoperatively. Results: Baseline characteristics of all groups were similar. Helium preconditioning did not significantly alter the primary outcome (molecular levels of kinases PKC-e and HSP-27, ratio of activated p38 MAPK or ERK 1/2). Postoperative troponin T was 11 arbitrary units [5, 31; area-under-the-curve (interquartile range)] for controls, and no statistically significant changes were observed after helium preconditioning [He-pre: 11 (6, 18)], helium postconditioning [He-post: 11 (8, 15)], helium pre-and postconditioning [He-PP: 14 (6, 20)] and after sevoflurane preconditioning [APC: 12 (8, 24), p = 0.13]. No adverse effects related to study treatment were observed in this study. Conclusions: No effect was observed of helium preconditioning, postconditioning or the combination thereof on activation of p38 MAPK, ERK 1/2 or levels of HSP27 and PKC-e in the human heart. Helium pre-and postconditioning did not affect postoperative troponin release in patients undergoing CABG surgery

Perturbative Corrections for Staggered Four-Fermion Operators

We present results for one-loop matching coefficients between continuum four-fermion operators, defined in the Naive Dimensional Regularization scheme, and staggered fermion operators of various types. We calculate diagrams involving gluon exchange between quark lines, and ``penguin'' diagrams containing quark loops. For the former we use Landau gauge operators, with and without $O(a)$ improvement, and including the tadpole improvement suggested by Lepage and Mackenzie.For the latter we use gauge-invariant operators. Combined with existing results for two-loop anomalous dimension matrices and one-loop matching coefficients, our results allow a lattice calculation of the amplitudes for $K\bar K$ mixing and $K\to\pi\pi$ decays with all corrections of $O(g^2)$ included. We also discuss the mixing of $\Delta S=1$ operators with lower dimension operators, and show that, with staggered fermions, only a single lower dimension operator need be removed by non-perturbative subtraction.Comment: 44 pages latex (uses psfig), 3 ps figures, all bundled using uufiles (correctly this time!), UW/PT-93-

Identification of molluscan nicotinic acetylcholine receptor (nAChR) subunits involved in formation of cation- and anion-selective nAChRs

Acetylcholine (ACh) is a neurotransmitter commonly found in all animal species. It was shown to mediate fast excitatory and inhibitory neurotransmission in the molluscan CNS. Since early intracellular recordings, it was shown that the receptors mediating these currents belong to the family of neuronal nicotinic acetylcholine receptors and that they can be distinguished on the basis of their pharmacology. We previously identified 12 Lymnaea cDNAs that were predicted to encode ion channel subunits of the family of the neuronal nicotinic acetylcholine receptors. These Lymnaea nAChRs can be subdivided in groups according to the residues supposedly contributing to the selectivity of ion conductance. Functional analysis in Xenopus oocytes revealed that two types of subunits with predicted distinct ion selectivities form homopentameric nicotinic ACh receptor (nAChR) subtypes conducting either cations or anions. Phylogenetic analysis of the nAChR gene sequences suggests that molluscan anionic nAChRs probably evolved from cationic ancestors through amino acid substitutions in the ion channel pore, a mechanism different from acetylcholine-gated channels in other invertebrates