944 research outputs found
Marinari-Parisi and Supersymmetric Collective Field Theory
A field theoretic formulation of the Marinari-Parisi supersymmetric matrix
model is established and shown to be equivalent to a recently proposed
supersymmetrization of the bosonic collective string field theory. It also
corresponds to a continuum description of super-Calogero models. The
perturbation theory of the model is developed and, in this approach, an
infinite sequence of vertices is generated. A class of potentials is identified
for which the spectrum is that of a massless boson and Majorana fermion. For
the harmonic oscillator case, the cubic vertices are obtained in an oscillator
basis. For a rather general class of potentials it is argued that one cannot
generate from Marinari-Parisi models a continuum limit similar to that of the
d=1 bosonic string.Comment: 45 page
Racemic tricarbonyl[7-methoxy-2-(η6-phenyl)chromane]chromium(0)
In the title compound, [Cr(C16H16O2)(CO)3], the Cr0 atom of the Cr(CO)3 unit is coordinated to the phenyl ring of the flavan ligand in an η6 mode, with a normal arene-to-metal distance. The Cr(CO)3 unit exhibits a three-legged piano-stool conformation, while the dihydropyran ring displays a distorted envelope configuration. The phenyl ring is twisted away from the fused ring system by 25.5 (2)°. The methoxy group is almost coplanar with the phenyl ring [CMe—O—Car—Car torsion angle = 8.46 (2)°]. The crystal packing is stabilized by intermolecular C—H⋯O interactions
A Continuum Description of Super-Calogero Models
An investigation is made of the super-Calogero model with particular emphasis
on its continuum formulation and possible application in the context of
supersymmetrizing the bosonic collective d=1 string field theory.Comment: 80 page
Estimation of recharge using a revised CRD method
The cumulative rainfall departure (CRD) method, based on the water-balance principle, is often used for mimicking of
water level fluctuations. Because of its simplicity and minimal requirement of spatial data, the CRD method has been
applied widely for estimating either effective recharge or aquifer storativity, and consequently gained a focus in South
Africa. This paper critically reviews this method and proposes expanded algorithm. Validation of the method under typical
South African conditions is discussed based on model-generated and known cases. The study is aided with a user-friendly
Excel program called Recharge Estimation Model in Excel (REME).Web of Scienc
Racemic tricarbonyl[(4a,5,6,7,8,8a-η)-2-phenyl-3,4-dihydro-2H-1-benzopyran]chromium(0)
The title compound, [Cr(C15H14O)(CO)3], displays a distorted envelope configuration of the dihydropyrane ring. The dihedral angle between the phenyl and phenylene rings is 50.63 (4)°. The Cr0 atom is coordinated by three CO groups and the phenylene ring of the flavan ligand in an η6 mode, with a common arene-to-metal distanc
Supersymmetry and integrability for a class of XY central spin models
Several studies have exploited the integrable structure of central spin
models to deepen understanding of these fundamental systems. In recent years,
an underlying supersymmetry for systems with XX interactions has been
uncovered. Here we report that a class of central spin models with XY
interactions is also supersymmetric and integrable. The associated Bethe Ansatz
solution is presented for the case where all particles are spin-1/2.Comment: 9 pages, no figure
Capture zone simulation for boreholes located in fractured dykes using the linesink concept
Delineation of capture zones for groundwater source protection is normally performed by using numerical codes which are based
on the porous medium flow equation. However, boreholes are often sited in or along permeable dykes or single fracture zones
through which aquifers are drained. It is very important to take into account dyke-influenced aquifers. This paper makes use of
Linesink to simulate permeable dyke or fractured zones and utilises the pathline distribution to delineate the capture zones.
Conditions when the influence of a fractured dyke can be considered negligible are also discussed through comparison with
stagnation point in a uniform flow field. The approach may be sufficient to illustrate protection zoning requirements when dyke
aquifers are considered.Web of Scienc
Advantages and disadvantages of partial codification of directors’ duties in the South African Companies Act 71 of 2008
This article offers a critical examination of partial codification and its effect on the interpretation of the directors’ standard of conduct provision. Previously, the fiduciary duties and the duty of care and skill were regulated by the common law and case law. In May 2004, the Department of Trade and Industry released a policy document entitled South African company law for the 21st century: Guidelines for corporate law reform. The policy document acknowledged that South Africa had no extensive statutory dispensation that covered the duties of directors. The policy document recognised the need to bring South African company law in line with international trends and to reflect and accommodate the changing environment for businesses locally and internationally. For the first time in South Africa’s corporate law history, the Companies Act 71 of 2008 partially codifies the fiduciary duties of directors, the duty of care and skill, and introduces the business judgement rule (also referred to as the ‘safe-harbour provisions’) into South African company law. The Companies Act 71 of 2008 prescribes certain duties and its extent, but the content of those duties, such as bona fides, is still determined by the common law
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