The Revolutionary Power of Boredom

This philosophical presentation uses Sara Ahmed\u27s writings on how our habits and routines make up the flow of life to explore one of the most time-consuming habits that people take part in: our technology and social media usage. Analyzing this habit leads us to understand what future it orients us towards; that being the archive and the image. Using Roberto Simanoski\u27s book Waste, this analysis of the archive leads us to conclude that our media usage causes us to view life as without character and meaning and thus, as boring. Jeremy Weissman adds to this exploration of the archive, revealing that the censorship inherent in it also causes us to dull ourselves into acceptable modes of being and again, become boring. Turning to the analysis of the image, Neil Postman and Weissman show us that images present the world and others as flat and without character which causes us to perceive the world itself as boring and meaningless. Byung-Chul Han\u27s work presents us with a possible solution: by disconnecting from the meaningless scroll of life as found in our devices, we can sit with our boredom and learn to perceive the world in new ways and thus recreate ourselves. Conducted in Philosophy 331: Contemporary European Philosophy with Dr. Stone.https://commons.und.edu/as-showcase/1013/thumbnail.jp

Four-dimensional symplectic cobordisms containing three-handles

We construct four-dimensional symplectic cobordisms between contact three-manifolds generalizing an example of Eliashberg. One key feature is that any handlebody decomposition of one of these cobordisms must involve three-handles. The other key feature is that these cobordisms contain chains of symplectically embedded two-spheres of square zero. This, together with standard gauge theory, is used to show that any contact three-manifold of non-zero torsion (in the sense of Giroux) cannot be strongly symplectically fillable. John Etnyre pointed out to the author that the same argument together with compactness results for pseudo-holomorphic curves implies that any contact three-manifold of non-zero torsion satisfies the Weinstein conjecture. We also get examples of weakly symplectically fillable contact three-manifolds which are (strongly) symplectically cobordant to overtwisted contact three-manifolds, shedding new light on the structure of the set of contact three-manifolds equipped with the strong symplectic cobordism partial order.Comment: This is the version published by Geometry & Topology on 28 October 200

A study of the relationship between health awareness, lifestyle behaviour and food label usage in Gauteng

Background: The objectives of the study were to determine whether consumers who read food labels, were also more aware of health and lifestyle issues, in terms of nutrition and other health-related lifestyle behaviours, and whether there was a relationship between food-label reading, health awareness and lifestyle behaviour. A quantitative descriptive (survey) design was selected to investigate the relationship between food-label reading on the one hand, and health awareness and lifestyle behavior on the other.Method: A two-stage, stratified-proportionate and systematic sampling strategy was applied to select a sample of 357 Gauteng respondents to complete a telephonic questionnaire. Respondents who were most likely to read food label information were selected. Food label information is prescribed by comprehensive label legislation. Data report on respondents’ label-reading habits, attitudes towards health awareness, lifestyle behaviour and biographic data. Nonparametric analysis, scale reliability tests, analysis of variance (ANOVA) and Bonferroni multiple comparisons of means tests were used to analyse the results.Results: Results indicate that the two-thirds of respondents who, to some extent read nutritional information on food labels, were concerned about their personal health, were interested in health-related information, and followed a healthy lifestyle, such as regularly eating fresh fruit and vegetables, cutting back on alcohol, and other positive lifestyle behaviours. They were unsure about how their own knowledge of nutrition,and their understanding of nutrition information on food labels, compared with that of other consumers.Conclusion: A relationship was found between patterns of reading food labels, health awareness and lifestyle behaviour. People who often read food labels were more health-conscious, and maintained a healthier lifestyle.Keywords: health awareness, lifestyle, food labels, South Africa, consumer

Magnetic fields and accretion flows on the classical T Tauri star V2129 Oph

From observations collected with the ESPaDOnS spectropolarimeter, we report the discovery of magnetic fields at the surface of the mildly accreting classical T Tauri star V2129 Oph. Zeeman signatures are detected, both in photospheric lines and in the emission lines formed at the base of the accretion funnels linking the disc to the protostar, and monitored over the whole rotation cycle of V2129 Oph. We observe that rotational modulation dominates the temporal variations of both unpolarized and circularly polarized line profiles. We reconstruct the large-scale magnetic topology at the surface of V2129 Oph from both sets of Zeeman signatures simultaneously. We find it to be rather complex, with a dominant octupolar component and a weak dipole of strengths 1.2 and 0.35 kG, respectively, both slightly tilted with respect to the rotation axis. The large-scale field is anchored in a pair of 2-kG unipolar radial field spots located at high latitudes and coinciding with cool dark polar spots at photospheric level. This large-scale field geometry is unusually complex compared to those of non-accreting cool active subgiants with moderate rotation rates. As an illustration, we provide a first attempt at modelling the magnetospheric topology and accretion funnels of V2129 Oph using field extrapolation. We find that the magnetosphere of V2129 Oph must extend to about 7R* to ensure that the footpoints of accretion funnels coincide with the high-latitude accretion spots on the stellar surface. It suggests that the stellar magnetic field succeeds in coupling to the accretion disc as far out as the corotation radius, and could possibly explain the slow rotation of V2129 Oph. The magnetospheric geometry we derive produces X-ray coronal fluxes typical of those observed in cTTSs.Comment: MNRAS, in press (18 pages, 17 figures

Thermal activation between Landau levels in the organic superconductor β′′\beta''-(BEDT-TTF)2_{2}SF5_{5}CH2_{2}CF2_{2}SO3_{3}

We show that Shubnikov-de Haas oscillations in the interlayer resistivity of the organic superconductor $\beta''$-(BEDT-TTF)$_{2}$SF$_{5}$ CH$_{2}$CF$_{2}$SO$_{3}$ become very pronounced in magnetic fields $\sim$~60~T. The conductivity minima exhibit thermally-activated behaviour that can be explained simply by the presence of a Landau gap, with the quasi-one-dimensional Fermi surface sheets contributing negligibly to the conductivity. This observation, together with complete suppression of chemical potential oscillations, is consistent with an incommensurate nesting instability of the quasi-one-dimensional sheets.Comment: 6 pages, 4 figure

Analysis of MRE11's function in the 5′→3′ processing of DNA double-strand breaks

The resection of DNA double-strand breaks (DSBs) into 3′ single-strand tails is the initiating step of homology-dependent repair pathways. A key player in this process is the MRE11-RAD50-NBS1 complex, but its contribution to and mechanistic role in resection are not well understood. In this study, we took advantage of the Xenopus egg extract system to address these questions. We found that depletion of MRE11 caused a dramatic inhibition of 5′-resection, even for the first nucleotide at the 5′-end. Depletion of Xenopus CtIP also inhibited 5′-strand resection, but this inhibition could be alleviated by excess MRN. Both MRE11 and CtIP could be bypassed by a DNA that carried a 3′-ss-tail. Finally, using purified proteins, we found that MRN could stimulate both the WRN-DNA2-RPA pathway and the EXO1 pathway of resection. These findings provide important insights into the function of MRE11 in 5′-strand resection

Identification of the Xenopus DNA2 protein as a major nuclease for the 5′→3′ strand-specific processing of DNA ends

The first step of homology-dependent DNA double-strand break (DSB) repair is the 5′ strand-specific processing of DNA ends to generate 3′ single-strand tails. Despite extensive effort, the nuclease(s) that is directly responsible for the resection of 5′ strands in eukaryotic cells remains elusive. Using nucleoplasmic extracts (NPE) derived from the eggs of Xenopus laevis as the model system, we have found that DNA processing consists of at least two steps: an ATP-dependent unwinding of ends and an ATP-independent 5′→3′ degradation of single-strand tails. The unwinding step is catalyzed by DNA helicases, the major one of which is the Xenopus Werner syndrome protein (xWRN), a member of the RecQ helicase family. In this study, we report the purification and identification of the Xenopus DNA2 (xDNA2) as one of the nucleases responsible for the 5′→3′ degradation of single-strand tails. Immunodepletion of xDNA2 resulted in a significant reduction in end processing and homology-dependent DSB repair. These results provide strong evidence that xDNA2 is a major nuclease for the resection of DNA ends for homology-dependent DSB repair in eukaryotes

Mechanistic analysis of Xenopus EXO1's function in 5′-strand resection at DNA double-strand breaks

The processing of DNA double-strand breaks (DSBs) into 3′ single-stranded tails is the first step of homology-dependent DSB repair. A key player in this process is the highly conserved eukaryotic exonuclease 1 (EXO1), yet its precise mechanism of action has not been rigorously determined. To address this issue, we reconstituted 5′-strand resection in cytosol derived from unfertilized interphase eggs of the frog Xenopus laevis. Xenopus EXO1 (xEXO1) was found to display strong 5′→3′ dsDNA exonuclease activity but no significant ssDNA exonuclease activity. Depletion of xEXO1 caused significant inhibition of 5′ strand resection. Co-depletion of xEXO1 and Xenopus DNA2 (xDNA2) showed that these two nucleases act in parallel pathways and by distinct mechanisms. While xDNA2 acts on ssDNA unwound mainly by the Xenopus Werner syndrome protein (xWRN), xEXO1 acts directly on dsDNA. Furthermore, xEXO1 and xWRN are required for both the initiation stage and the extension stage of resection. These results reveal important novel information on the mechanism of 5′-strand resection in eukaryotes

Single-stranded DNA catenation mediated by human EVL and a type I topoisomerase

The human Ena/Vasp-like (EVL) protein is considered to be a bifunctional protein, involved in both actin remodeling and homologous recombination. In the present study, we found that human EVL forms heat-stable multimers of circular single-stranded DNA (ssDNA) molecules in the presence of a type I topoisomerase in vitro. An electron microscopic analysis revealed that the heat-stable ssDNA multimers formed by EVL and topoisomerase were ssDNA catemers. The ssDNA catenation did not occur when either EVL or topoisomerase was omitted from the reaction mixture. A deletion analysis revealed that the ssDNA catenation completely depended on the annealing activity of EVL. Human EVL was captured from a human cell extract by TOPO IIIα-conjugated beads, and the interaction between EVL and TOPO IIIα was confirmed by a surface plasmon resonance analysis. Purified TOPO IIIα catalyzed the ssDNA catenation with EVL as efficiently as the Escherichia coli topoisomerase I. Since the ssDNA cutting and rejoining reactions, which are the sub-steps of ssDNA catenation, may be an essential process in homologous recombination, EVL and TOPO IIIα may function in the processing of DNA intermediates formed during homologous recombination