Saint Mary's Faculty Articles and Other Works
http://library2.smu.ca:80/handle/01/21880
2017-05-27T08:11:45ZWilliam and Margaret McCalla: The 1938 Trip Through the Northwest United States
http://library2.smu.ca:80/handle/01/26942
William and Margaret McCalla: The 1938 Trip Through the Northwest United States
McCalla, Peggy; McCalla, Robert
William (Will) Copeland McCalla was born in St. Catharines, Ontario, Canada in 1872. Margaret Adam Ratcliffe was born in the same place in 1880. They married in 1902. He was a prosperous market gardener in the St. Catharines area until selling the farm in the winter of 1912-13 and taking up residence in Edmonton, Alberta. From an early age Will was interested in plants, flowers and photography. In 1899, for example, he made a collecting and photography trip to Banff, with free transportation provided by the CPR in exchange for photographs. In 1920 he published an illustrated book, Wild Flowers of Western Canada (Toronto: Mussen Book Co.) which was distributed to all public schools in Alberta. In 1925 he took up a teaching position at the Calgary Normal School where he remained until his retirement in 1938. Each summer, and often throughout the year, he and Margaret would take collecting and photography trips for wildflowers. Both kept journals of their trips: Will a photographic record and a specimen record of his collecting, with Margaret keeping the daily log. What follows is a compilation of their trip in 1938 to the Northwestern United States focussing on the National Parks of the area. The compilation combines Will’s photographic record and Margaret’s daily log1. In this compilation some of the photographs and specimens collected are shown, along with an indication of where they may be found today. Especially featured are the coloured hand painted lantern slides that were produced from some of the black and white photographs taken.
2017-01-01T00:00:00ZModelling the extreme X-ray spectrum of IRAS 13224-3809
http://library2.smu.ca:80/handle/01/26929
Modelling the extreme X-ray spectrum of IRAS 13224-3809
The extreme narrow-line Seyfert 1 galaxy IRAS 13224-3809 shows significant variability, frequency depended time lags, and strong Fe K line and Fe L features in the long 2011 XMM-Newton observation. In this work we study the spectral properties of IRAS 13224-3809 in detail, and carry out a series of analyses to probe the nature of the source, focusing in particular on the spectral variability exhibited. The reflection grating spectrometer spectrum shows no obvious signatures of absorption by partially ionized material (‘warm’ absorbers). We fit the 0.3-10.0 keV spectra with a model that includes relativistic reflection from the inner accretion disc, a standard power-law active galactic nucleus continuum, and a low-temperature (~0.1 keV) blackbody, which may originate in the accretion disc, either as direct or reprocessed thermal emission. We find that the reflection model explains the time-averaged spectrum well, and we also undertake flux-resolved and time-resolved spectral analyses, which provide evidence of gravitational light-bending effects. Additionally, the temperature and flux of the blackbody component are found to follow the L [alpha] T[superscript 4] relation expected for simple thermal blackbody emission from a constant emitting area, indicating a physical origin for this component.
Pre-print version/PDF
2015-01-01T00:00:00ZDeformation by cocycles of pointed Hopf algebras over non-abelian groups
http://library2.smu.ca:80/handle/01/26925
Deformation by cocycles of pointed Hopf algebras over non-abelian groups
We introduce a method to construct explicitly multiplicative 2-cocycles for bosonizations of Nichols algebras B(V ) over Hopf algebras H. These cocycles arise as liftings of H-invariant linear functionals on V [circle times] V and give a close formula to deform braided commutator-type relations. Using this construction, we show that all known finite dimensional pointed Hopf algebras over the dihedral groups D[subscript m] with m = 4t [greater than or equal to] 12, over the symmetric group S[subscript 3] and some families over S[subscript 4] are cocycle deformations of bosonizations of Nichols algebras.
Post-print
2015-01-01T00:00:00ZOn rigidity of Nichols algebras
http://library2.smu.ca:80/handle/01/26914
On rigidity of Nichols algebras
We study deformations of graded braided bialgebras using cohomological methods. In particular, we show that many examples of Nichols algebras, including the finite-dimensional ones arising in the Andruskiewitsch-Schneider program of classification of pointed Hopf algebras, are rigid. This result can be regarded as nonexistence of “braided Lie algebras” with nontrivial bracket.
Post-print
2015-12-01T00:00:00ZCoherent information of one-mode Gaussian channels - the general case of nonzero added classical noise
http://library2.smu.ca:80/handle/01/26913
Coherent information of one-mode Gaussian channels - the general case of nonzero added classical noise
We prove that whenever the coherent information of a one-mode Gaussian channel is non-zero its supremum is achieved for the infinite input power. This is a well established fact for the zero added classical noise, whereas the nonzero case has not been studied in detail. The presented analysis fills the gap for three canonical classes of one-mode Gaussian channels: the lossy, amplifying and additive classical noise channel class. For the remaining one-mode Gaussian channel classes the coherent information is known to vanish.
Post-print
2015-03-02T00:00:00ZA new measurement of the neutron detection efficiency for the NaI Crystal Ball detector
http://library2.smu.ca:80/handle/01/26911
A new measurement of the neutron detection efficiency for the NaI Crystal Ball detector
We report on a measurement of the neutron detection efficiency in NaI crystals in the Crystal Ball detector obtained from a study of single [pi][superscript 0] photoproduction on deuterium using the tagged photon beam at the Mainz Microtron. The results were obtained up to a neutron energy of 400 MeV. They are compared to previous measurements made more than 15 years ago at the pion beam at the BNL AGS.
Pre-print
2015-04-07T00:00:00ZDouble-ended queues and joint moments of left-right canonical operators on full Fock space
http://library2.smu.ca:80/handle/01/26910
Double-ended queues and joint moments of left-right canonical operators on full Fock space
We follow the guiding line offered by canonical operators on the full Fock space, in order to identify what kind of cumulant functionals should be considered for the concept of bi-free independence introduced in the recent work of Voiculescu. By following this guiding line we arrive to consider, for a general noncommutative probability space ([alpha], [phi]), a family of “(l, r)-cumulant functionals” which enlarges the family of free cumulant functionals of the space. In the motivating case of canonical operators on the full Fock space we find a simple formula for a relevant family of (l, r)-cumulants of a (2d)-tuple (A[subscript 1], . . . , A[subscript d], B[subscript 1], . . . , B[subscript d]), with A[subscript 1], . . . , A[subscript d] canonical operators on the left and B[subscript 1], . . . , B[subscript d] canonical operators on the right. This extends a known one-sided formula for free cumulants of A[subscript 1], . . . , A[subscript d], which establishes a basic operator model for the R-transform of free probability.
Post-print
2015-02-12T00:00:00ZDeterminants of innovation and productivity in the service sector in Mexico
http://library2.smu.ca:80/handle/01/26886
Determinants of innovation and productivity in the service sector in Mexico
Drawing on survey data about firms in Mexico, we investigate the determinants of innovation and the linkages between innovation and productivity in the services sector. We apply a three-stage
Crépon-Duguet-Mairesse (CDM) econometric model; the use of manufacturing firms as a benchmark helps to better appreciate our findings. We find that a series of structural, performance, and behavioral factors increase a firm’s propensity to invest in innovation, but some differences arise between services and manufacturing firms. Intensive investment in innovation leads to superior innovation performance, while innovation output has a positive effect on labor productivity.
Pre-print
2015-06-17T00:00:00ZHiking a generalized Dyck path: a tractable way of calculating multimode boson evolution operators
http://library2.smu.ca:80/handle/01/26885
Hiking a generalized Dyck path: a tractable way of calculating multimode boson evolution operators
A time evolution operator in the interaction picture is given by exponentiating an interaction Hamiltonian H. Important examples of Hamiltonians, often encountered in quantum optics, condensed matter and high energy physics, are of a general form H = r(A[superscript dagger] − A), where A is a multimode boson operator and r is the coupling constant. If no simple factorization formula for the evolution operator exists, the calculation of the evolution operator is a notoriously difficult problem. In this case the only available option may be to Taylor expand the operator in r and act on a state of interest [psi]. But this brute-force method quickly hits the complexity barrier since the number of evaluated expressions increases exponentially. We relate a combinatorial structure called Dyck paths to the action of a boson word (monomial) and a large class of monomial sums on a quantum state [psi]. This allows us to cross the exponential gap and make the problem of a boson unitary operator evaluation computationally tractable by achieving polynomial-time complexity for an extensive family of physically interesting multimode Hamiltonians. We further test our method on a cubic boson Hamiltonian whose Taylor series is known to diverge for all nonzero values of the coupling constant and an analytic continuation via a Padé approximant must be performed.
Post-print
2015-11-01T00:00:00ZEconomic benefits of studying economics in Canada: a comparison of wages of economics majors with wages in other fields of study, circa 2005
http://library2.smu.ca:80/handle/01/26884
Economic benefits of studying economics in Canada: a comparison of wages of economics majors with wages in other fields of study, circa 2005
We compared the wages of economics degree holders with of those in 49 other fields of study using data from the 2006 Canadian population census. At the undergraduate level, economics majors earned the sixth highest average wage in 2005. When demographic controls were applied, they ranked ninth on the salary scale. When we compared the wages in 15 fields that require students to take math courses, economists ranked in the middle, as they also did when working as managers and professionals. When working as business and finance professionals, economists had wages surpassed only by finance majors. At the graduate level, economics majors had a greater wage advantage over all of the other fields except for business majors. These results are useful for Canadian university economics departments that have been experiencing declining enrolments over the past few years. In addition, we hope they will enable students to make more informed choices regarding their academic discipline. The results also highlight the need to direct greater policy attention towards developing mathematical skills among incoming university students as a prerequisite for them to build analytical skills, the demand for which in the labour market has been demonstrated in some Canadian and US studies.
Publisher's version/PDF
2015-01-01T00:00:00Z