956 research outputs found
Conditional sampling for barrier option pricing under the LT method
We develop a conditional sampling scheme for pricing knock-out barrier
options under the Linear Transformations (LT) algorithm from Imai and Tan
(2006). We compare our new method to an existing conditional Monte Carlo scheme
from Glasserman and Staum (2001), and show that a substantial variance
reduction is achieved. We extend the method to allow pricing knock-in barrier
options and introduce a root-finding method to obtain a further variance
reduction. The effectiveness of the new method is supported by numerical
results
The oral microbiome and adverse pregnancy outcomes.
Significant evidence supports an association between periodontal pathogenic bacteria and preterm birth and preeclampsia. The virulence properties assigned to specific oral pathogenic bacteria, for example, Fusobacterium nucleatum, Porphyromonas gingivalis, Filifactor alocis, Campylobacter rectus, and others, render them as potential collaborators in adverse outcomes of pregnancy. Several pathways have been suggested for this association: 1) hematogenous spread (bacteremia) of periodontal pathogens; 2) hematogenous spread of multiple mediators of inflammation that are generated by the host and/or fetal immune response to pathogenic bacteria; and 3) the possibility of oral microbial pathogen transmission, with subsequent colonization, in the vaginal microbiome resulting from sexual practices. As periodontal disease is, for the most part, preventable, the medical and dental public health communities can address intervention strategies to control oral inflammatory disease, lessen the systemic inflammatory burden, and ultimately reduce the potential for adverse pregnancy outcomes. This article reviews the oral, vaginal, and placental microbiomes, considers their potential impact on preterm labor, and the future research needed to confirm or refute this relationship
Factors predicting walking intolerance in patients with peripheral arterial disease and intermittent claudication
Objective. To determine which physiological variables conduce to walking intolerance in patients with peripheral arterial disease (PAD). Design. The physiological response to a graded treadmill exercise test (GTT) in patients with PAD was characterised. Setting. Patients were recruited from the Department of Vascular Surgery, Groote Schuur Hospital, Cape Town. Subjects. Thirty-one patients diagnosed with PAD were included in the study. Outcome measures. During a GTT, peak oxygen consumption (VO2peak), peak minute ventilation (VEpeak), peak heart rate and peak venous lactate concentrations were measured and compared with those from a comparison group. Anklebrachial index (ABI) was measured at rest and after exercise.
During the GTT, maximum walking distance (MWD) and pain-free walking distance (PFWD) were measured to determine walking tolerance. Results. Peak venous lactate concentrations did not correlate significantly with either PFWD (r=–0.08; p=0.3) or MWD (r=–0.03; p=0.4). Resting ABI did not correlate with either MWD (r=0.09; p=0.64) or PFWD (r=–0.19; p=0.29). Subjects terminated exercise at significantly (p<0.05) lower levels of cardiorespiratory effort and venous lactate concentrations than did a sedentary but otherwise healthy comparison group: peak heart rate 156±11 v. 114±22 beats per minute (BPM); p=0.001; and peak venous lactate concentration 9.7±2.7 mmol/l v. 3.28±1.39 mmol/l; p=0.001. Conclusion. Perceived discomfort in these patients is not caused by elevated blood lactate concentrations, a low ABI or limiting cardiorespiratory effort but by other factors not measured in this study
Mechanisms of the training response in patients with peripheral arterial disease – a review
Exercise training has proved to be a beneficial treatment for patients with peripheral arterial disease (PAD) suffering from the symptom of intermittent claudication. The mechanism by which symptomatic improvement occurs is unclear. The review summarises the mechanism of the training response in patients with PAD, focusing on improvements in bloodflow as well as biochemical, muscle recruitment and psychological adaptations. Possible areas of future research are suggested
Building Interprofessional Global Health Infrastructure at a University and Health System: Navigating Challenges and Scaling Successes
Mission:
Global Jefferson will create sustainable programs of global distinction through collaboration that position Jefferson as a local and international destination and resource for education, research, and clinical activities.
Global Jefferson is supported by the Associate Provost for Global Affairs, part of the Office of the Provost.
Global activity at Jefferson includes: Global Health Initiatives Committee (GHIC) Service Learning Global Research & Exchange between institutions Pre-clinical, translational, clinical, and applied research
Poster presented at: 8th Annual Global Health Conference of the Consortium of Universities for Global Health (CUGH)https://jdc.jefferson.edu/globalhealthposters/1000/thumbnail.jp
Adiabaticity Conditions for Volatility Smile in Black-Scholes Pricing Model
Our derivation of the distribution function for future returns is based on
the risk neutral approach which gives a functional dependence for the European
call (put) option price, C(K), given the strike price, K, and the distribution
function of the returns. We derive this distribution function using for C(K) a
Black-Scholes (BS) expression with volatility in the form of a volatility
smile. We show that this approach based on a volatility smile leads to relative
minima for the distribution function ("bad" probabilities) never observed in
real data and, in the worst cases, negative probabilities. We show that these
undesirable effects can be eliminated by requiring "adiabatic" conditions on
the volatility smile
Osteotomies in the Cervical Spine
Rigid cervical deformities are difficult problems to treat. The goals of surgical treatment include deformity correction, achieving a rigid fusion, and performing a thorough neural decompression. In stiff and ankylosed cervical spines, osteotomies are required to restore sagittal and coronal balance. In this chapter, we describe the clinical and radiographic workup for patients with cervical deformities, and delineate the various factors that must be considered when planning surgical treatment. We also describe in detail the various types of cervical osteotomies, along with their surgical technique, advantages, and potential complications
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