This paper presents noise analysis of a regenerative analog FREQUENCY divider at microwave C band FREQUENCY. Using harmonic balance and conversion matrix methods, by considering a simple noise model for active device, phase and amplitude noise spectrum densities for the FREQUENCY divider (without considering the noise of excitation signal) are calculated and simulated.

Introduction Acne is a common complain among post rhinoplasty patients. While rhinoplasty is done for aesthetic reasons and acne expressively affects the individual’ s appearance, we aimed to study its incidence and role players. Materials and Methods: A descriptive cross-sectional study was performed on 152 (143 females and 9 males) patients admitted for rhinoplasty during January 2016 to March 2017. Patients were examined by a dermatologist prior to surgery and 7, 30 and 90 days after rhinoplasty using the Global Acne Grading System and responded to a list of questions on the probable risk factors of acne. Psychological status was examined by the perceived stress scale-14 and the Hospital Anxiety and Depression Scale. Results: The patients' mean age was 28. 9± 3. 82 yrs. Mild and moderate acne were observed in 21. 7% (n=33) of the cases in the preoperative visit. The incidence of mild and moderate acne was 36. 1%, 42. 8% and 23% after 7, 30 and 90 days of surgery, respectively. One week after rhinoplasty, acne manifested in 14. 9% of cases with no history of acne. Mean age significantly differed between those with and without post-surgical acne at all post-surgical visits (P >0. 001 and P=0. 001 and P=0. 015, respectively). Hospital anxiety and depression and perceived stress levels were significantly higher in patients who presented with acne on the first post-surgical visit compared to those with no acne presentations (P=0. 04 and P=0. 02, respectively). Conclusion: External psychological stress may be the main role player in post-rhinoplasty acne. Consultation or referral of patients to an experienced psychologist is highly recommended for a better outcome and fewer complications.

Background: We investigated the rate of vaginal childbirth and Cesarean and its causes in maternity wards of Imam Khomeini Educational Hospital in Ahwaz the capital city of Khuzestan Province and Al- Hadi Hospital in Shoostar as a traditional city. Methods: In this comparative descriptive study data were obtained from medical records of birth deliveries in six months (March to September) in year 2007. Data were analyzed using SPSS software. Results: The results show a total rate of 29% Cesarean and 71% vaginal childbirth in hospitals. The rate of Cesarean in Imam and Al -Hadi Hospitals was 23% and 33%, respectively. The main cause of Cesarean in Imam and Al-Hadi Hospitals was failure of labor progression (35% and 33%, respectively). Most Cesarean s were occurred in an age range of 20-25 yr. Conclusion: Comparing with international acceptable rate (20-22%), Cesarean rate in both hospitals was high. It seems special attention should be made by persons, committees or organizations in charge of community health to child birth practices in both hospitals.

Background: Systemic sclerosis is an autoimmune connective tissue disorder which is characterised by cutaneous and internal organ fibrosis. Raynaud’s phenomenon is the earliest feature and may precede the onset of the disease by months to years. The heart, lungs, gastrointestinal tract, kidneys and other organs may be involved. Our aim was to evaluate skin thickness and echogenicity in systemic sclerosis patients by ultrasound and compare it with the healthy age and sex matched controls.Method: Our study included 15 successively admitted patients (14 females and 1 male) with systemic sclerosis and 15 healthy age and sex matched controls. All the patients met the ACR criteria of diagnosis. The age range of the patients was 25-55 years. The disease duration ranged from 1-8 years. A complete history and physical examination was done for each patient. Skin thickness and echogenicity were measured by a 20MHz ultrasound probe at 6 different anatomical sites which was compared with that of the controls.Result: Skin thickness was more in systemic sclerosis patients (significant p value) as compared to controls, and echogenicity was inversely proportional to the skin thickness.Conclusion: Skin ultrasonography is a noninvasive method which can reflect the severity of skin involvement and periodic assessment of skin thickness and echogenicity can help to monitor the progression of the disease.

Background and purpose: Delirium is a recurrent cognitive disorder which is one of the most common neurologic diagnosis in patients who have had pelvic surgeries. This complication occurs in a short time and early diagnosis results in early management. Current study was done to investigate the FREQUENCY of delirium and identifying the factors affecting its incidence in patients with pelvic surgeries. Materials and methods: This analytical study was performed in patients >60 years of age admitted in orthopedic wards in Rasht hospitals, Iran, due to pelvic surgery. The samples (n=252) were selected using convenience sampling. Data were collected using a demographic questionnaire and the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria. All patients were examined before the surgery, at 6, 24, 48, and 72 hours after the surgery and also before discharge in which their cognitive status and average cognitive scores were recorded. Results: We investigated 252 patients (mean age: 72. 90± 7. 33) including 67 (26. 6%) males and 185 (73. 4%) females of whom 69% were married. Overall incidence of delirium was 18. 3%. Significant association was found between the incidence of delirium and history of smoking, psychiatric medications (P< 0. 001), and the type of anesthesia (P< 0. 05). Conclusion: This study showed high prevalence of delirium in patients who have had pelvic surgery. Therefore, more focus on the factors affecting the incidence of delirium before the surgery and evaluation of patients early after the surgery could be beneficial in reducing the rate of delirium.

Background: Some skiers suffer from medical symptoms during or after skiing, especially downhill skiing. However, there has been no investigation on medical problems in skiers. In this study, our main objective was to evaluate the FREQUENCY of medical symptoms during or after ski among Iranian skiers.Methods: This cross sectional descriptive study was performed in winter of the year 2005, at Dizin piste (Iran). We evaluated demographic data and medical history of skiers, as well as the FREQUENCY of medical symptoms during ski using a questionnaire. The relations between sex, medical and drug history, smoking habits, and symptoms were assessed by chi-squared and fisher’s exact test. The relation between age, duration of skiing, history of previous skiing (in years) and symptoms was analyzed by means of independent t- test. P <0.05 was considered significant.Findings: Out of 1448 skiers, 74% were male and the mean age of subjects was 25.2 (±8.4) years. A total of 1208 skiers wore medical glasses or lenses during skiing, and visual disorders were found in 15.2% of skiers. Among all subjects, one medical symptom was found in 20.1% and two medical symptoms or more in 3.6%. The most common clinical profile was headache, nystagmus and true vertigo. Occurrence of symptoms had significant association with wearing glasses or lenses during routine life, habit of smoking and previous ski injury. Alcohol consumption was seen in 31.2% skiers, and it had a borderline relation with incidence of symptoms. There was not any association between incidence of symptoms and sex, age, duration of skiing, wearing glasses or lenses during skiing, and history of motion sickness. Conclusion: There were at least two symptoms in 3.6% of skiers. This finding shows ski sickness is different from other altitude sicknesses.