67 research outputs found
Normal Approximation to a Sum of Geometric Random Variableswith Application to Ammunition Stockpile Planning
The normal approximation for a sum of geometric random variables has been examined. Thisapproximation is relevant to the determination of direct-fire ammunition stockpile levels in adefence setting. Among the methodologies available for this assessment, one is a target-orientedmethodology. This approach calculates the number of rounds necessary to destroy a givenfraction of the enemy force and infrastructure. The difficulty is that the number of rounds requiredcannot be determined analytically. An obvious numeric approach is Monte Carlo simulation.Another is the approximation approach which has several advantages like it is easy to implement.and is accurate even in the case where the number of targets is low
A review of the Dividend Discount Model: from deterministic to stochastic models
This chapter presents a review of the dividend discount models starting from
the basic models (Williams 1938, Gordon and Shapiro 1956) to more recent and
complex models (Ghezzi and Piccardi 2003, Barbu et al. 2017, D'Amico and De
Blasis 2018) with a focus on the modelling of the dividend process rather than
the discounting factor, that is assumed constant in most of the models. The
Chapter starts with an introduction of the basic valuation model with some
general aspects to consider when performing the computation. Then, Section 1.3
presents the Gordon growth model (Gordon 1962) with some of its extensions
(Malkiel 1963, Fuller and Hsia 1984, Molodovsky et al. 1965, Brooks and Helms
1990, Barsky and De Long 1993), and reports some empirical evidence. Extended
reviews of the Gordon stock valuation model and its extensions can be found in
Kamstra (2003) and Damodaran (2012). In Section 1.4, the focus is directed to
more recent advancements which make us of the Markov chain to model the
dividend process (Hurley and Johnson 1994, Yao 1997, Hurley and Johnson 1998,
Ghezzi and Piccardi 2003, Barbu et al. 2017, D'Amico and De Blasis 2018). The
advantage of these models is the possibility to obtain a different valuation
that depends on the state of the dividend series, allowing the model to be
closer to reality. In addition, these models permit to obtain a measure of the
risk of the single stock or a portfolio of stocks
Meditation-based interventions for family caregivers of people with dementia: a review of the empirical literature
Objectives: Providing care for a family member with dementia is associated with increased risk of adverse mental health sequelae. Recently, interventions utilising meditation-based techniques have been developed with the aim of reducing psychological distress among dementia caregivers. The present review aimed to critically evaluate the extant empirical literature in order to determine: (1) whether meditation-based interventions can reduce depression among dementia caregivers and (2) whether meditation-based interventions can reduce subjective burden among dementia caregivers.
Method: After adhering to inclusion and exclusion criteria, a total of eight studies were included in the present review. Methodological quality was assessed using one of two scales dependent on study design.
Results: The results provide tentative evidence that meditation-based interventions do indeed improve levels of depression and burden in family dementia caregivers.
Conclusions: The review highlighted the strengths and weakness of the studiesâ methodological designs. Whilst this novel review offers evidence in support of meditation-based interventions to improve the psychological distress of family dementia caregivers, future research should direct efforts to conduct larger scale, more rigorous studies. Clinical implications of the findings are also discussed
Relativistic wave equations for interacting massive particles with arbitrary half-intreger spins
New formulation of relativistic wave equations (RWE) for massive particles
with arbitrary half-integer spins s interacting with external electromagnetic
fields are proposed. They are based on wave functions which are irreducible
tensors of rank n=s-\frac12$) antisymmetric w.r.t. n pairs of indices,
whose components are bispinors. The form of RWE is straightforward and free of
inconsistencies associated with the other approaches to equations describing
interacting higher spin particles
On the linear forms of the Schrodinger equation
Generalizing the linearisation procedure used by Dirac and later by
L\'evy-Leblond, we derive the first-order non-relativistic wave equations for
particles of spin 1 and spin 3/2 starting from the Schrodinger equation
Prevalence of drug-resistant minority variants in untreated HIV-1-infected individuals with and those without transmitted drug resistance detected by sanger sequencing
Minority variant human immunodeficiency virus type 1 (HIV-1) nonnucleoside reverse transcriptase inhibitor (NNRTI) resistance mutations are associated with an increased risk of virological failure during treatment with NNRTI-containing regimens. To determine whether individuals to whom variants with isolated NNRTI-associated drug resistance were transmitted are at increased risk of virological failure during treatment with a non-NNRTI-containing regimen, we identified minority variant resistance mutations in 33 individuals with isolated NNRTI-associated transmitted drug resistance and 49 matched controls. We found similar proportions of overall and nucleoside reverse transcriptase inhibitor-associated minority variant resistance mutations in both groups, suggesting that isolated NNRTI-associated transmitted drug resistance may not be a risk factor for virological failure during treatment with a non-NNRTI-containing regimen. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved
Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures
Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo
Across-the-board Parimutuel Bets
Recently I competed in a club golf competition where there was organized parimutuel betting on the outcome. I made an across-the-board (ATB) bet of $20 on our team to win, place, and show. Subsequently I wondered whether this was the best thing to do. Hence, this paper examines the theory of an optimal ATB parimutuel bet. The goal is to develop principles that would guide such wagering when a bettor has only limited information about the sizes of the betting pools and the relative probabilities of finish of the various teams.
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