Model for Risk Calculation and Reliability Comparison of Level Crossings.

There is not a single country in the world that is so rich that it can remove all level crossings or provide their denivelation in order to absolutely avoid the possibility of accidents at the intersections of railways and road traffic. In the Republic of Serbia alone, the largest number of accidents occur at passive crossings, which make up three-quarters of the total number of crossings. Therefore, it is necessary to constantly find solutions to the problem of priorities when choosing level crossings where it is necessary to raise the level of security, primarily by analyzing the risk and reliability at all level crossings. This paper presents a model that enables this. The calculation of the maximal risk of a level crossing is achieved under the conditions of generating the maximum entropy in the virtual operating mode. The basis of the model is a heterogeneous queuing system. Maximum entropy is based on the mandatory application of an exponential distribution. The system is Markovian and is solved by a standard analytical concept. The basic input parameters for the calculation of the maximal risk are the geometric characteristics of the level crossing and the intensities and structure of the flows of road and railway vehicles. The real risk is based on statistical records of accidents and flow intensities. The exact reliability of the level crossing is calculated from the ratio of real and maximal risk, which enables their further comparison in order to raise the level of safety, and that is the basic idea of this paper.

Mathematical identification of influential parameters on the elastic buckling of variable geometry plate.

The problem of elastic stability of plates with square, rectangular, and circular holes as well as slotted holes was discussed. The existence of the hole reduces the deformation energy of the plate and it affects the redistribution of stress flow in comparison to a uniform plate which causes a change of the external operation of compressive forces. The distribution of compressive force is defined as the approximate model of plane state of stress. The significant parameters of elastic stability compared to the uniform plate, including the dominant role of the shape, size, and orientation of the hole were identified. Comparative analysis of the shape of the hole was carried out on the data from the literature, which are based on different approaches and methods. Qualitative and quantitative accordance of the results has been found out and it verifies exposed methodology as applicable in the study of the phenomenon of elastic stability. Sensitivity factor is defined that is proportional to the reciprocal value of the buckling coefficient and it is a measure of sensitivity of plate to the existence of the hole. Mechanism of loss of stability is interpreted through the absorption of the external operation, induced by the shape of the hole.

Effects of onion (Allium cepa L.) and garlic (Allium sativum L.) essential oils on the Aspergillus versicolor growth and sterigmatocystin production.

In the present study the effects of individual and combined essential oils (EOs) extracted from onion (Allium cepa L.) bulb and garlic (Allium sativum L.) clove on the growth of Aspergillus versicolor and sterigmatocystin (STC) production were investigated. The EOs obtained by hydrodistillation were analyzed by GC/MS. Twenty one compounds were identified in onion EO. The major components were: dimethyl-trisulfide (16.64%), methyl-propyl-trisulfide (14.21%), dietil-1,2,4-tritiolan (3R,5S-, 3S,5S- and 3R,5R- isomers) (13.71%), methyl-(1-propenyl)-disulfide (13.14%), and methyl-(1-propenyl)-trisulfide (13.02%). The major components of garlic EO were diallyl-trisulfide (33.55%), and diallyl-disulfide (28.05%). The mycelial growth and the STC production were recorded after 7, 14, and 21 d of the A. versicolor growth in Yeast extract sucrose (YES) broth containing different EOs concentrations. Compared to the garlic EO, the onion EO showed a stronger inhibitory effect on the A. versicolor mycelial growth and STC production. After a 21-d incubation of fungi 0.05 and 0.11 µg/mL of onion EO and 0.11 µg/mL of garlic EO completely inhibited the A. versicolor mycelial growth and mycotoxins biosynthesis. The combination of EOs of onion (75%) and garlic (25%) had a synergistic effect on growth inhibition of A. versicolor and STC production.

[Functional hearing examinations in patients suffering from diabetes mellitus type 1 in regard to disease duration].

INTRODUCTION: Problems of hearing disturbances in persons suffering from diabetes have been attracting great attention for many decades. MATERIAL AND METHODS: In this study we examined the auditory function of 50 patients suffering from diabetes mellitus type 1 of different duration by analyzing results of pure-tone audiometry and brainstem auditory evoked potentials. The obtained results of measuring were compared to 30 healthy subjects from the corresponding age and gender group. The group of diabetic patients was divided according to the disease duration (I group 0-5 years; II group 6-10 years, III group over 10 years). RESULTS AND DISCUSSION: A statistically significant increase of sensorineural hearing loss was found in the diabetics according to the duration of their disease (I group = 14.09%, II group = 21.39%, III group = 104.89%). The results of the brain stem auditory evoked potentials, the significance threshold being p = 0.05 between the controls and the diabetics at all levels of absolute latency of right and left sides, did not show significant differences in the mean values. In the case of interwave latencies, the diabetic patients were found to have a significant qualitative difference of intervals I-III and I-V on both ears in the sense of internal distribution of response. In cases of sensorineural hearing loss we found a significant connection with prolonged latencies of I wave on the right ear and of I and V waves on the left ear. In all probability, the cause of these results could be found in distinctive individuality of the organism reactions to the consequences of this disease (disturbance in the distal part of N. cochlearis). CONCLUSION: The results of research have shown the existence of a significant sensorineural hearing loss in the patients with diabetes mellitus type 1 in accordance to the disease duration. We also found qualitative changes of brainstem auditory evoked potentials in the diabetic patients in comparison to the controls as well as significant quantitative changes in regard to the presence of sensorineural hearing loss of the patients.

[Correlation of hearing function findings in regard to other, subsequent complication of diabetes mellitus type 1].

INTRODUCTION: Hearing loss is considered to be a subsequent complication of diabetes. MATERIAL AND METHODS: Auditory function was analyzed in 50 patients suffering from diabetes mellitus type I, and through results of pure-tone audiometry and brainstem auditory evoked potentials in regard to the existence of subsequent complications of the disease, diabetic neuropathy (n=20) and retinopathy (n=13). RESULTS AND DISCUSSION: The results were correlated with the ones in those having a disease, but without these complications and the control group of 30 healthy examinees of the adequate gender and age. Patients suffering from this disease for over 10 years (83.33%), were found to have high frequency of diabetic neuropathy, increased average sensorineural hearing loss (73.04%). The average age was significantly higher (35.5 +/- (3SD = 5.3) in accordance with 23.2 +/- (3 SD = 6.3), and the disease lasted much longer (17.5 years towards 5.7 years) in those suffering from neuropathy. In the presence of diabetic retinopathy it was found that the average sensorineural hearing loss was increased for 50.43%, in comparison to those without signs of retinopathy. The average sensorineural hearing loss was found to be higher for 62.58% to 76.81% in patients with retinopathy preproliferance and retinopathy profilerance than in those with established retinopathy nonprolferance. In the presence of diabetic retinopatlhy, a significant difference was observed in latencies of ll and IV waves from the right, and latencies of I, IV and V waves from the left ear, this is, interwaves latencies of I-III on the right ear and III-V and I-V on the left ear. CONCLUSION: Subsequent complications of diabetes mellitus type I (neuropathy and retinopathy) have positive correlation with the significant level of sensorineural hearing loss, particulary expressed in function of patients' age, and latencies extention of brainstem auditory evoked potentials.

Correlation of hearing function findings in patients suffering from diabetes mellitus type 1 in regard to age and gender.

Ageing of an individual affects hearing impairment and associated diseases can have a cumulative affect. In 50 examined subjects suffering from Diabetes Mellitus type 1, who were divided into groups according to age, gender and disease duration, auditory function was tested by analyzing results of pure-tone audiometry and brainstem auditory evoked potentials. The obtained results were correlated with the results of 30 healthy controls adequately represented by age and gender. Starting from the age group 30-39 we noticed a significant reduction in the percentage of regular findings in comparison with the control group, as well as an increase in the percentage of sensorineural hearing impairment and mean values of hearing impairment (-dB). In regard to gender, we found a continuing and significant increase in sensorineural hearing impairment in the examined male subjects from the group with the disease. The analysis and correlation of brainstem auditory evoked potentials regarding the age of the examinees did not show any significant impact on the increase in the mean values of the diseased and the controls, whereas regarding the gender, we noticed a significant impact on the increase in the mean values of absolute latencies II (Fd/l = 5.1249/9.8144), III (Fd/l = 14.0413/9.3169), IV (Fd/l =7.1413/6.3410) and V (Fd/l = 12.8753/6.1208) waves as well as of interwave latencies I-III (Fd/l = 5.2193/4.9628) mutually in the male examinees. In the diseased group there were significant differences of interwave latencies I-III in men and women both on the left and the right side, M here the values in the female subjects were significantly shorter than in the males.