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

Medication use by Team South Africa during the XXVIIIth Olympiad: A model for quantity estimation for multi-coded team events

Objective. This descriptive study was undertaken to report the medications used by the athletes and officials of Team South Africa at the 2004 Olympic Games and to provide a model for the estimation of quantities to be used for planning support to future events. Setting. South African medical facility, 2004 Olympic Games, Athens, Greece. Methods. The names of the medications, including the dosage and quantity of medications dispensed, were recorded in the pharmacy stock control book at the South African medical facility, 2004 Olympic Games, Athens, Greece. Retrospective review of patient files and medical encounter forms was also undertaken to check against the pharmacy stock control book to ensure complete data capture of dispensed medications. Main outcome measures. Quantities of medications consumed during the observation period. The units of medication consumed per travelling team member were calculated by dividing the number of units (tablets, capsules, tubes, inhalers, bottles and ampoules) used during the trip by the total number of travelling team members. Results. Complete records of medications included in the travelling pharmacy are described. Quantities of medications included ranged from single units to 2 250 units and percentage use of various medications varied from 0% to 100% of stocks. Units per team member ranged from 0 to 9.43. Medications were consumed from all categories of agents. The most utilised agents included the analgesics, musculoskeletal and non-steroidal anti-inflammatory agents as well as certain vitamin and mineral supplements. Conclusions. This study describes the consumption of pharmacological agents by the athletes and officials of Team South Africa during the Athens 2004 Olympic Games. It also provides a model to assist with the estimation of quantities of medications to be included in the travelling pharmacy for future international multi-coded sports events

Relationship between thoracic kyphosis and neural axis abnormalities in patients with adolescent idiopathic scoliosis.

Purpose:Previous studies have suggested an association between increased thoracic kyphosis and neural axis abnormalities in patients with adolescent idiopathic scoliosis (AIS). However, the basis for this finding is unclear, and this association has been mainly noted in retrospective studies on a non-consecutive series of patients. The purpose of this study was to assess the relationship between thoracic kyphosis and neural axis abnormalities in patients with AIS. Methods:We studied a consecutive series of AIS patients treated with spinal fusion. Thoracic kyphosis (T2 to T12) was measured from preoperative lateral radiographs. All patients underwent a spine magnetic resonance imaging (MRI) prior to surgery, and MRI reports were reviewed to determine the presence of neural axis abnormalities. Statistical analyses included descriptive statistics and chi-squared analysis. Results:This study included 210 patients with AIS. There were no significant differences in age or gender between patients with thoracic hypokyphosis (kyphosis < 20°), normal thoracic kyphosis (kyphosis 20° to 40°) and thoracic hyperkyphosis (kyphosis > 40°) (p > 0.05). Neural axis abnormalities were present in 17.9% of patients with thoracic hypokyphosis, 9.8% of patients with normal thoracic kyphosis and 13.6% of patients with thoracic hyperkyphosis (p = 0.60). There were no significant differences in rates of Chiari malformation, syrinx, intra-spinal masses and other central nervous system abnormalities between groups (p > 0.05). Conclusions:Thoracic kyphosis was not associated with neural axis abnormalities in our consecutive series of patients with AIS. Increased thoracic kyphosis may not be a reliable indicator for the presence of neural axis abnormalities in patients with AIS. Level of Evidence:IV

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

If the shoe fits... should you just wear it? A complete calcaneal stress fracture in a female recreational runner

Shoe choice by runners may follow trends related to purported generalised benefits rather than following an individual risk- benefit analysis. The benefits and risks related to minimalist footwear for running has been a much debated topic. The authors report a case of a complete calcaneal stress fracture in an otherwise healthy female recreational runner in the first three weeks following her conversion from a traditional cushioned running shoe to a minimalist type of running shoe. Clinicians should be aware of the potential added bone stress with reduced cushioning and the potential risks in transitioning to new footwear

Profile of medical and injury consultations of Team South Africa during the XXVIIIth Olympiad, Athens 2004

Objective. This descriptive study was undertaken to document the nature of medical and injury consultations of the athletes and officials of the South African Team at the 2004 Olympic Games, and to provide data for planning future events. Setting. South African medical facility, 2004 Olympic Games, Athens, Greece. Methods. Total number of consultations and diagnoses were ascertained from medical logs and patient files which were completed daily by the members of the medical team. A retrospective clinical audit of medical records was then undertaken and the data were then compared with similar data collected during the Sydney 2000 Olympic Games. Acute and chronic-soft tissue (muscle strain, ligament sprain, tendon injury, contusion or laceration) and bony injury were analysed in terms of nature of injury, grading of severity and anatomical region injured. Main outcome measures. Number of consultations due to medical complaints or injuries among athletes and officials. Results. A total of 180 medical consultations were logged during the time in Athens while 348 consultations were logged in Sydney. The daily consultation rate was 6 per day in Athens compared with 13 per day in Sydney. In Athens, 84% of consultations were with athletes and the remainder (16%) with officials - this was similar to Sydney. The most common medical complaints in Athens were dermatological (16%), ENT (13%), and respiratory (8%) in nature, which contrasts with the profile of consultations in Sydney (ENT 18%; neurological system 16% and respiratory 16%). Acute injury and chronic injury accounted for 26% and 14% of consultations respectively. In Athens, the most common acute and chronic injuries were soft-tissue injuries. The most common acute injury regions were the foot and ankle (25%), upper leg (17%) and knee (17%). A total 77% of acute injuries were grade I, 17% grade II and 6% grade III in severity. The most common chronic injury regions were foot and ankle (32%), lumbar spine (32%), and shoulder (11%). These injury profiles were similar to those documented in Sydney 2000. Conclusions. Injury and illness complaints of the South African team were fewer in Athens 2004 compared with those documented during Sydney 2000. This can be attributed to local environmental conditions and travel across time zones. These data should be useful for planning medical services for future multi-coded events. The analysis of the nature of consultations suggests that it should be a prerequisite for physicians travelling with a multi-coded events team to have broad knowledge of both medical and injury management of athletes. Specifically, a sound knowledge of the management of soft-tissue injury is an important prerequisite for the personnel of the medical team

Persistent pain following ankle sprain: Bilateral accessory soleus muscles

Persistent pain following ankle sprain remains a difficult diagnostic and management dilemma. We report a 22 year old rugby player who presented with a persistent painful left ankle following a minor ankle sprain. After examination and imaging investigations, a symptomatic accessory soleus muscle was diagnosed on the left ankle, and an asymptomatic accessory soleus muscle on the right

Healthy lifestyle interventions in general practice: Part 15: Lifestyle and lower back pain

Lower back pain (LBP) is one of the most common medical problems in the adult population. LBP can be defined as pain, muscle tension or stiffness that is localised below the costal margin (inferior rib cage) and above the inferior gluteal folds and that can present either with or without leg pain (sciatica), and it can be classified as “specific” or “non-specific”. LBP has a high lifetime prevalence and is associated with a substantial direct and indirect cost to the individual and society. In this review, the focus is on the identification of lifestyle risk factors and interventions that are associated with mainly non-specific chronic LBP. In addition to pharmacotherapy, the best treatment approach is exercise therapy (including physical reconditioning), psychosocial and behavioural intervention and therapeutic education. Other lifestyle changes include nutritional intervention and smoking cessation

New transit observations for HAT-P-30 b, HAT-P-37 b, TrES-5 b, WASP-28 b, WASP-36 b, and WASP-39 b

We present new transit light curves for planets in six extrasolar planetary systems. They were acquired with 0.4-2.2 m telescopes located in west Asia, Europe, and South America. When combined with literature data, they allowed us to redetermine system parameters in a homogeneous way. Our results for individual systems are in agreement with values reported in previous studies. We refined transit ephemerides and reduced uncertainties of orbital periods by a factor between 2 and 7. No sign of any variations in transit times was detected for the planets studied.Comment: Submitted to Acta Astronomic

Minima Times of Three Selected Systems in Cancer

We present several CCD minima times