773 research outputs found
Bone mineral density in Iranian patients: Effects of age, sex, and body mass index
Introduction: Osteoporosis is a multifactorial skeletal disease that is characterized by reduced bone mineral density (BMD). BMD values de-pend on several factors such as age, sex and age at menopause. The purpose of this study was to determine the prevalence and changes in bone mineral density in Iranian patients. Meth-ods: Three hundred patients were selected through random sampling technique in 2009. BMD was assessed by Norland (Excell) technique at the lumbar and femoral neck. Weight and height were measured through standard methods. A thorough history was taken from each patient. The data was analyzed using SPSS software version 13.0. P-values less than 0.05 were con-sidered statistically significant. Results: From among the 300 studied patients, 86.6% were fe-male. their mean age was 52.7 years. Their av-erage body mass index (BMI) was 28.14 kg/m2. Mean T-Score at lumbar spine and femoral neck was −1.07 ± 1.19 and −1.75 ± 1.33 respectively. Mean BMD value at lumbar spine and femoral neck was 0.92 ± 0.19 and 0.77 ± 0.16 respectively. The prevalence of osteoporosis at lumbar spine and femoral neck was 33.7% and 16.7, respec-tively. There was a significant correlation be-tween age, BMI and BMD values (P-Value < 0.01). Correlation between gender and BMD value at the lumbar spine and femoral neck was not sig-nificant. Conclusion: This study shows that age- ing and low BMI are risk factors associated with bone loss. it is recommended to measure BMD and implement prevention programs for high- risk people.
Keywords: Bone Mineral Density; Body Mass Index;Age; Gende
Pulmonary tuberculosis and some underlying conditions in Golestan Province of Iran, during 2001-2005
Context: Pulmonary tuberculosis has been a major health problem in Golestan province of Iran. Aims: This descriptive cross-sectional study was performed to evaluate the frequency of coexisting medical conditions and their effects on some epidemiologic factors in patients with pulmonary tuberculosis. Setting and Design: This was a descriptive cross-sectional study. Methods and Material: Demographic information, time of admission in the hospital and coexisting medical conditions (diabetes, chronic renal failure/hemodyalysis, corticosteroids consumption and malignancies) were extracted from the patient's file. Statistical analysis used: Chi-square test was used to assess the relationship between variables. Results: Two hundred forty three patients with pulmonary tuberculosis during 5 years were studied. Out of all, 162 cases (66.7%) did not have any co-morbidities. Diabetes mellitus was found to be the most prevalent condition (23.05%) followed by chronic renal failure, corticosteroid consumption and malignancy ranking second, third and forth in the list (5.8%, 2.5% and 2 respectively). The mean age of the patients was 50.15±19 years old. In the group without co morbidities, male/ female ratio was 1.41/1, but co morbidity with diabetes was significantly more prevalent in females (p<0.05). Conclusions: We suggest screening of tuberculosis in patients with chronic renal failure and diabetes mellitus in our area. Also for patients with pulmonary tuberculosis, diabetes screening should be considered essential
Distributions of Historic Market Data -- Relaxation and Correlations
We investigate relaxation and correlations in a class of mean-reverting
models for stochastic variances. We derive closed-form expressions for the
correlation functions and leverage for a general form of the stochastic term.
We also discuss correlation functions and leverage for three specific models --
multiplicative, Heston (Cox-Ingersoll-Ross) and combined multiplicative-Heston
-- whose steady-state probability density functions are Gamma, Inverse Gamma
and Beta Prime respectively, the latter two exhibiting "fat" tails. For the
Heston model, we apply the eigenvalue analysis of the Fokker-Planck equation to
derive the correlation function -- in agreement with the general analysis --
and to identify a series of time scales, which are observable in relaxation of
cumulants on approach to the steady state. We test our findings on a very large
set of historic financial markets data.Comment: 17 pages, 8 figures, 3 table
Distribution of Historic Market Data – Implied and Realized Volatility
We undertake a systematic comparison between implied volatility, as represented by VIX (new methodology) and VXO (old methodology) and realized volatility. We do not find substantial difference in accuracy between VIX and VXO. We compare visually and statistically the distributions of realized and implied variance (volatility squared) and study the distribution of their ratio. The ratio distributions are studied both for the known realized variance (for the current month) and for the predicted realized variance (for the following month). We show that the ratio of the two is best fitted by a Beta Prime distribution, whose shape parameters depend strongly on which of the two months is used
Satisfaction with hearing aids among aged patients with different degrees of hearing loss and length of daily use
Background and Objectives: The evaluation of subjective benefits and positive effects of hearing aids in daily is important for measuring the treatment outcome. The aim of this project was to investigate the degree of satisfaction of aged users with their hearing aids using the Satisfaction with Amplification in Daily Life (SADL) scale, which emphasizes non-auditory factors contributing to satisfaction as well as benefit. Subjects and Methods: The Persian version of SADL scale was completed by 40 patients who received monaural hearing aid fitting at south of the Iran from December 2013 and March 2014. SADL subscales of the SADL were evaluated according to the type and degree of hearing loss, the pure tone audiogram pattern and shape and type of the hearing aid. Results: The results associated with the SADL subscales revealed a greater satisfaction associated with the Positive Effect and Service and Costs subscales. Subjects with different degree of hearing loss were very satisfied in terms of positive effect subscale. Conclusions: Participants reported a considerable level of satisfaction with their hearing aids. Appropriate guidance for using hearing aids and spending more time for counseling can improve the satisfaction level of this age group. © 2015 The Korean Audiological Society
Are there Dragon Kings in the Stock Market?
We undertake a systematic study of historic market volatility spanning
roughly five preceding decades. We focus specifically on the time series of
realized volatility (RV) of the S&P500 index and its distribution function. As
expected, the largest values of RV coincide with the largest economic upheavals
of the period: Savings and Loan Crisis, Tech Bubble, Financial Crisis and Covid
Pandemic. We address the question of whether these values belong to one of the
three categories: Black Swans (BS), that is they lie on scale-free, power-law
tails of the distribution; Dragon Kings (DK), defined as statistically
significant upward deviations from BS; or Negative Dragons Kings (nDK), defined
as statistically significant downward deviations from BS. In analyzing the
tails of the distribution with RV > 40, we observe the appearance of
"potential" DK which eventually terminate in an abrupt plunge to nDK. This
phenomenon becomes more pronounced with the increase of the number of days over
which the average RV is calculated -- here from daily, n=1, to "monthly," n=21.
We fit the entire distribution with a modified Generalized Beta (mGB)
distribution function, which terminates at a finite value of the variable but
exhibits a long power-law stretch prior to that, as well as Generalized Beta
Prime (GB2) distribution function, which has a power-law tail. We also fit the
tails directly with a straight line on a log-log scale. In order to ascertain
BS, DK or nDK behavior, all fits include their confidence intervals and
p-values are evaluated for the data points to check if they can come from the
respective distributions.Comment: 20 pages, 15 figue
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