Longitudinal studies are very common in medical, behavioral, and interventional sciences. One measure of effect of interest in longitudinal studies is RISK RATIO, naturally estimated by log-binomial regression which suffers from convergence problems. Odds RATIO (OR) does not approximate RISK RATIO (RR) well when the outcome is common, so alternative methods have been introduced in cohort studies with one follow-up visit. In this paper, we illustrate two simple methods: the COPY method and the modified log-Poisson regression for RR estimation in longitudinal data setting. Our unpublished simulation study on RR estimation in longitudinal data setting suggests that the COPY method performs well in terms of closeness of the RR estimate and true RR (mean square error) and so we suggest this method for RR estimation in longitudinal data setting.

The main purpose of banking regulation is promoting banks resilience in crisis and reducing banks RISK. This occurs by the market and regulatory pressure. In this paper, we attempt to investigate the causal relationship between capital adequacy RATIO (CAR) and RISK, adequacy of capital requirement in controlling RISK and explore bank's behavior in a different level of capital RATIO. Using data of Iranian banks in period of 1389-1394 and simultaneous equation model (SEM), the results show that first, there is mutual causal relationship between RISK and capital, second, besides the regulatory pressure, market discipline affect the changes of capital RATIO, and finally low-capitalized bank adjust their capital slower than other banks.

Relative RISK (RR) and Odds RATIO (OR) are two measures of RISK which has been widely used in epidemiological studies. The cohort studies are designed to directly compute a relative RISK, but the situation is somewhat more complicated in the case-control design. In these studies, the odds RATIO gives a valid estimate of the effect size. There is not a serious problem if you don’t use of the odds RATIO as an estimator of relative RISK, but the problem begins when the odds RATIO used as a surrogate for relative RISK while its meaning is forgotten as the RATIO of tow odds. The author has tried, to describe the relationship between relative RISK and odds RATIO and also the right time to use each of theme for those who familiar with the basic concept of epidemiologic studies. In this paper, the concepts of probability and chance and definitions refer to relative RISK and odds RATIOs and characteristics of each have been reported. Afterward the gaps between RR and OR according to their computational formulas are described and a simple method to estimate the OR to RR RATIO is expressed.

The world is embroiled in a pandemic of a new coronavirus at the end of 2019 and early in 2020, with such a large scale that it has severely involved the political, economic, and social systems in most countries around the world. The scale of the crisis is so widespread that many experts believe that the post-corona world will be substantially different from the pre-corona world. In the face of this massive epidemic, how people perceive RISK and how to RISK is communicated, plays a central role in deciding and choosing people's behavior. Fighting with this emerging phenomenon requires mobilizing all the possibilities of society and helping all people in the field of empathy and altruism. In this article, we briefly review aspects of the important concept of RISK perception and communication in this pervasive crisis.

Introduction: Clinical use of the late responses during routine neurophysiological examination has significantly increased the diagnostic yield of the neurophysiological evaluation. The H max to M max RATIO (H/M RATIO) is considered a suitable index for illustrating the level of reflex excitability of the motor pool.Methods: In this study posterior tibial nerve H/M RATIO changes in cerebrovascular accidents (CVA) evaluated. This investigation was carried out in 22 normal subjects aged 40-65 years with mean 52 years, and in 40 patients with CVA aged 42-63 years with mean 57 years.Results: In normal subjects no significant differences were found between the mean values observed between right and left sides. In patients significant increased H/M RATIOs in both sides with more in non-plegic leg (P<0.01) were found. The facilitation of Babinsky sign in patients is significantly associated with low H/M RATIOs (P=0.003). The H/M RATIO changes were not significantly associated with severity of hemiplegia (P=0.3 for lower extremities, P=0.9 for upper extremities). The H/M RATIO was increased in ischemic lesions (P<0.01), but in intracerebral hemorrhages the soleus H/M RATIO increases in non-plegic side the same as the plegic side.Conclusion: The posterior tibial nerve H/M RATIOs are increased in CVA bilaterally due to decreased presynaptic inhibition Ia terminals, thus amplitude of H reflexes increased without increased amplitude of M response.

The method of selection of the study design decides the type of analysis 10 be used. Case-Control studies assess the causes of a particular outcome, comparing a group of individuals who have experienced the outcome under study with a group who have net.Results appear as a two by two table. As these two groups are sampled separately, the rate of the disease in the exposed or unexposed groups can not be calculated. However, the Odds RATIO can be obtained. The Odds RATIO is sometimes referred to as the cross product RATIO.                        Cases                            Controls Exposed            a                                  b Unexposed         c                                  d Odds RATIO (a/b)I (c/d) = ad/bc