289,602 research outputs found
Mary Douglas, risk and accounting failures.
Sociology and anthropology are especially valuable in providing a critical understanding of the risk-related implications of modernity. There has, however, been relatively little discussion of the work of Mary Douglas within accounting although her pioneering writings in the area of risk have been highly influential. This paper uses Douglas' cultural theory of risk to provide an alternative perspective on the demise of Enron and Andersen. The failure at Enron is interpreted through the grid-group model and analysed as a series of events that threaten to destabilize established cultures. Accounting is thus construed as an activity that exists on the margins of boundaries. There are two important conclusions drawn from the analysis. First, as the worldviews of both the individualist and hierarchical cultures became threatened by the ensuing crisis they collaborated to ensure their perpetuation. This also averted individuals from becoming susceptible to recruitment by subversive egalitarian groups. Second, the individualistic culture of Andersen shaped practices within the firm weakening its ability to act as a gatekeeper and therefore public accounting firms need to modify their cultures if they are to police the margins effectivel
An Extended Laplace Approximation Method for Bayesian Inference of Self-Exciting Spatial-Temporal Models of Count Data
Self-Exciting models are statistical models of count data where the
probability of an event occurring is influenced by the history of the process.
In particular, self-exciting spatio-temporal models allow for spatial
dependence as well as temporal self-excitation. For large spatial or temporal
regions, however, the model leads to an intractable likelihood. An increasingly
common method for dealing with large spatio-temporal models is by using Laplace
approximations (LA). This method is convenient as it can easily be applied and
is quickly implemented. However, as we will demonstrate in this manuscript,
when applied to self-exciting Poisson spatial-temporal models, Laplace
Approximations result in a significant bias in estimating some parameters. Due
to this bias, we propose using up to sixth-order corrections to the LA for
fitting these models. We will demonstrate how to do this in a Bayesian setting
for Self-Exciting Spatio-Temporal models. We will further show there is a
limited parameter space where the extended LA method still has bias. In these
uncommon instances we will demonstrate how a more computationally intensive
fully Bayesian approach using the Stan software program is possible in those
rare instances. The performance of the extended LA method is illustrated with
both simulation and real-world data
Modeling and Estimation for Self-Exciting Spatio-Temporal Models of Terrorist Activity
Spatio-temporal hierarchical modeling is an extremely attractive way to model
the spread of crime or terrorism data over a given region, especially when the
observations are counts and must be modeled discretely. The spatio-temporal
diffusion is placed, as a matter of convenience, in the process model allowing
for straightforward estimation of the diffusion parameters through Bayesian
techniques. However, this method of modeling does not allow for the existence
of self-excitation, or a temporal data model dependency, that has been shown to
exist in criminal and terrorism data. In this manuscript we will use existing
theories on how violence spreads to create models that allow for both
spatio-temporal diffusion in the process model as well as temporal diffusion,
or self-excitation, in the data model. We will further demonstrate how Laplace
approximations similar to their use in Integrated Nested Laplace Approximation
can be used to quickly and accurately conduct inference of self-exciting
spatio-temporal models allowing practitioners a new way of fitting and
comparing multiple process models. We will illustrate this approach by fitting
a self-exciting spatio-temporal model to terrorism data in Iraq and demonstrate
how choice of process model leads to differing conclusions on the existence of
self-excitation in the data and differing conclusions on how violence is
spreading spatio-temporally
Reviews
Eta De Cicco, Mike Farmer and James Hargrave, Using the Internet in Secondary Schools, London: Kogan Page (2nd edn), 2001. ISBN: 0â7494â3459â7. Softback, x + 192 pages, ÂŁ16.99
Not located type material of Pottiales described from Australia
Type material of several legitimately published taxa (Pottiales) described from Australia have not been located after a thorough search in major (relevant) herbaria. Comments on these taxa is given. Furthermore, not located nomina nuda are also listed
and Cross-Sections at the LHC
Measurements of the and cross-sections
at the LHC with data taken at TeV are reported for the ATLAS,
CMS, and LHCb experiments. All results are found to agree with the Standard
Model.Comment: 4 pages, 1 figur
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