5,471 research outputs found
"My novel, Hill of Fools"
R.L. Peteni - 'There is a tendency in human beings to pay no heed to events in small remote areas. They would rather concern themselves only with those events which make headlines, with political upheavals and industrial conflicts centred in large metropolitan regions. Yet there is always drama and human conflict in the humblest rural village. In selecting a pastoral theme and small fictitious villages in an obscure corner of Keiskammahoek as the setting of the novel, I had an ironic intention. Themes illustrated in these obscure villages would, I believed, have more universal application than they would if I had selected a larger centre, identifiable personages and known political trends. I did not want anybody to sit back, complacent, feeling that the spotlight was on Lennox Sebe’s Ciskei alone, or Kaiser Matanzima’s Transkei, or John Vorster’s apartheid South Africa. The spotlight is on the Ciskei, yes, on Transkei, on South Africa, on any other country where public life and personal relationships are bedevilled by tribalism or racialism or any form of sectionalism
A Possible Detection of Occultation by a Proto-planetary Clump in GM Cephei
GM Cep in the young (~ 4 Myr) open cluster Trumpler 37 has been known to be an abrupt variable and to have a circumstellar disk with very active accretion. Our monitoring observations in 2009–2011 revealed the star to show sporadic ?are events, each with brightening of . 0.5 mag lasting for days. These brightening events, associated with a color change toward the blue, should originate from an increased accretion activity. Moreover, the star also underwent a brightness drop of ~ 1 mag lasting for about a month, during which the star became bluer when fainter. Such brightness drops seem to have a recurrence time scale of a year, as evidenced in our data and the photometric behavior of GM Cep over a century. Between consecutive drops, the star brightened gradually by about 1 mag and became blue at peak luminosity. We propose that the drop is caused by obscuration of the central star by an orbiting dust concentration. The UX Orionis type of activity in GM Cep therefore exemplifies the disk inhomogeneity process in transition between grain coagulation and planetesimal formation in a young circumstellar disk
Trajan's Forum (Hemicycle) and Via Biberatica (Trajan's Markets): An HHpXRF Study of the Provenance of Lava Paving in Ancient Rome (Italy)
This paper reports on geochemical data collected using a He-enabled Hand-Held portable XRF (HHpXRF) from lava paving stones in Trajan’s Forum Hemicycle and the Via Biberatica (Rome). Issues relating to HHpXRF field use and calibration are also addressed in detail. Using this instrument 355 analyses of the paving stones were collected and the data was processed using the standard techniques of igneous petrology and petrography. Provenancing was based on comparisons between the HHpXRF data and geological data from the abundant literature on Roman volcanic rocks. These comparisons placed the provenance of the paving stones in the Colli Albani, southeast of Rome. Further analysis using Zr/Y vs Nb/Y discriminant diagrams suggests that the paving stones were quarried from two sources both of which are represented in Trajan’s Forum and the Via Biberatica. The diagrams suggest that the sources lie within the Faete and Vallerano lava complexes. The latter were probably transported to the construction site by barge on the River Tiber and the former were easily accessible by carts along the Via Appia. The study establishes the potential of HHpXRF equipment for non-destructive analysis of paving stones both in Rome and at other sites in central Italy and challenges a number of assumptions about the supply of building materials to Rome based on intuition alone
The Ha Luminosity Function and Star Formation Rate at z\sim 0.2
We have measured the Ha+[N II] fluxes of the I-selected Canada-France
Redshift Survey (CFRS) galaxies lying at a redshift z below 0.3, and hence
derived the Ha luminosity function. The magnitude limits of the CFRS mean that
only the galaxies with M(B) > -21 mag were observed at these redshifts. We
obtained a total Ha luminosity density of at least 10^{39.44\pm 0.04}
erg/s/Mpc^{3} at a mean z=0.2 for galaxies with rest-fame EW(Ha+[N II]) > 10
Angs. This is twice the value found in the local universe by Gallego et al.
1995. Our Ha star formation rate, derived from Madau (1997) is higher than the
UV observations at same z, implying a UV dust extinction of about 1 mag. We
found a strong correlation between the Ha luminosity and the absolute magnitude
in the B-band: M(B(AB)) = 46.7 - 1.6 log L(Ha). This work will serve as a basis
of future studies of Ha luminosity distributions measured from
optically-selected spectroscopic surveys of the distant universe, and it will
provide a better understanding of the physical processes responsible for the
observed galaxy evolution.Comment: Accepted for publication in ApJ, 14 pages, LaTeX (macro aas2pp4.sty),
6 figure
Theoretical study of a cold atom beam splitter
A theoretical model is presented for the study of the dynamics of a cold
atomic cloud falling in the gravity field in the presence of two crossing
dipole guides. The cloud is split between the two branches of this laser guide,
and we compare experimental measurements of the splitting efficiency with
semiclassical simulations. We then explore the possibilities of optimization of
this beam splitter. Our numerical study also gives access to detailed
information, such as the atom temperature after the splitting
Shear-melting of a hexagonal columnar crystal by proliferation of dislocations
A hexagonal columnar crystal undergoes a shear-melting transition above a
critical shear rate or stress. We combine the analysis of the shear-thinning
regime below the melting with that of synchrotron X-ray scattering data under
shear and propose the melting to be due to a proliferation of dislocations,
whose density is determined by both techniques to vary as a power law of the
shear rate with a 2/3 exponent, as expected for a creep model of crystalline
solids. Moreover, our data suggest the existence under shear of a line hexatic
phase, between the columnar crystal and the liquid phase
Closing International Law\u27s Innocence Gap
Over the last decade, a growing number of countries have adopted new laws and other mechanisms to address a gap in national criminal legal systems: the absence of meaningful procedures to raise post-conviction claims of factual innocence. These legal and policy reforms have responded to a global surge of exonerations facilitated by the growth of national innocence organizations that increasingly collaborate across borders. It is striking that these developments have occurred with little direct help from international law. Although many treaties recognize extensive fair trial and appeal rights, no international human rights instrument—in its text, existing interpretation, or implementation—explicitly and fully recognizes the right to assert a claim of factual innocence. We label this omission international law’s innocence gap. The gap appears increasingly anomalous given how foundational innocence protection has become at the national level, as well as international law’s longstanding commitment to the presumption of innocence, fair trial, and other criminal process guarantees. We argue the time has come to close this innocence gap by recognizing a new international human right to assert post-trial claims of factual innocence
Copyright Exceptions Across Borders: Implementing the Marrakesh Treaty
This article reviews state ratification and implementation of the Marrakesh Treaty since its conclusion in 2013. We find that most states have adhered closely to the Treaty’s text, thus creating a de facto global template of exceptions and limitations that has increasingly enabled individuals with print disabilities, libraries and schools to create accessible format copies and share them across borders. The article argues that the Marrakesh Treaty’s core innovation—mandatory exceptions to copyright to promote public welfare—together with consultations with a diverse range of stakeholders, may offer a model for harmonising human rights and IP in other contexts
From Instantons to Sphalerons: Time-Dependent Periodic Solutions of SU(2)-Higgs Theory
We solve numerically for periodic, spherically symmetric, classical solutions
of SU(2)-Higgs theory in four-dimensional Euclidean space. In the limit of
short periods the solutions approach tiny instanton-anti-instanton
superpositions while, for longer periods, the solutions merge with the static
sphaleron. A previously predicted bifurcation point, where two branches of
periodic solutions meet, appears for Higgs boson masses larger than .Comment: 14 pages, RevTeX with eps figure
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