Determination of isolated Aeromonas hydrophila antibiotic resistance profile from farmed common carp (Cyprinus carpio) in Khuzestan Province

Aeromonas are an example of emerging bacterial pathogens. Even though they have been recognized as primary fish and human pathogens. Aeromonas hydrophila are opportunistic pathogens that are at the same time infectious and enterotoxigenic and multiple antibiotic resistances (MAR) among Aeromonas hydrophila strains has been reported from many parts of the world. Under these circumstances, it will be worthwhile to find out the prevalence of antibiotic resistance of the Aeromonas hydrophila strains. The one hundred pieces of fish samples were collected from 4 common carp training pool in Khuzestan province. The part of intestine was collected in sterile plate and was homogenized. The samples were cultured in blood agar and incubated in 37centigrade degree temperature. Three to five Aeomonas hydrophila suspected colony, were selected from any plate and purified in blood agar. After initial evaluation of each colony by catalase, oxidase and gram staining, suspected strains DNA was extracted by boiling. Aeromonas hydrophila strains were confirmed by PCR assay and using of genus and species specific primers. Finally, multiple antibiotic resistance (MAR) of confirmed Aeromonas hydrophila isolates was evaluated by Kirby-Bauer disc diffusion method. Twenty Aeromonas hydrophila strains of Aeromonas suspected colonies were confirmed by PCR assay and the most of isolates had a multiple resistance. The least and the most resistance was observed regarding to cefotaxim and ciprofloxacin (<25%), vancomycin and clindamycin (90%), respectively. Compared with results of other studies, antibiotic resistance pattern of these bacterial strains is variable in different geographical areas; therefore resistant pattern of each group of bacteria must be determined in each area

MARKOV CHAIN MODEL FOR PROBABILITY OF DRY, WET DAYS AND STATISTICAL ANALISIS OF DAILY RAINFALL IN SOME CLIMATIC ZONE OF IRAN

Water scarcity is a major problem in arid and semi-arid areas. The scarcity of water is further stressed by the growing demand due to increase in population growth in developing countries. Climate change and its outcomes on precipitation and water resources is the other problem in these areas. Several models are widely used for modeling daily precipitation occurrence. In this study, Markov Chain Model has been extensively used to study spell distribution. For this purpose, a day period was considered as the optimum length of time. Given the assumption that the Markov chain model is the right model for daily precipitation occurrence, the choice of Markov model order was examined on a daily basis for 4 synoptic weather stations with different climates in Iran (Gorgan, Khorram Abad, Zahedan, Tabriz)during 1978-2009. Based on probability rules, events possibility of sequential dry and wet days, these data were analyzed by stochastic process and Markov Chain method. Then probability matrix was calculated by maximum likelihood method. The possibility continuing2-5days of dry and wet days were calculated. The results showed that the probability maximum of consecutive dry period and climatic probability of dry days has occurred in Zahedan. The probability of consecutive dry period has fluctuated from 73.3 to 100 percent. Climatic probability of occurrence of dry days would change in the range of 70.96 to 100 percent with the average probability of about 90.45 percent

Calibration and Measurement of Dielectric Properties of Finite Thickness Composite Sheets with Open-Ended Coaxial Sensors

The application of open-ended coaxial sensors for dielectric measurement of finite thickness composite sheets is studied. Expressions for calculation of the complex aperture admittance for two geometries are presented. These expressions are used to calculate the dielectric constant of infinite half-space as well as finite thickness slabs. A more efficient method of such calculations, using a personal computer, for low to medium loss dielectrics is demonstrated. The question of when a dielectric layer may be considered as infinitely thick is also addressed, and examples are presented. A different calibration technique (compared to the conventional ones) is described and successfully implemented. This calibration technique utilizes a dielectric sheet with known dielectric properties and thickness. Measurements for different airgaps between the open-ended coaxial line and the dielectric sheet are used to perform and enhance the calibration. The results of this calibration technique and several subsequent measurements are presented and discussed

Microwave Noncontact Examination of Disbond and Thickness Variation in Stratified Composite Media

Numerical and experimental results of a microwave noncontact, nondestructive detection and evaluation of disbonds and thickness variations in stratified composite media are presented. The aperture admittance characteristics of a flange mounted rectangular waveguide radiating into a layered, generally lossy dielectric media backed or unbacked by a conducting sheet is modeled. The theoretical implementation is based on a Fourier transform boundary matching technique to construct the field components in each medium, coupled with a stationary form of the terminating aperture admittance of the waveguide. The model can serve as a reliable test bed for real-time examination of layered composite media. Experimental results for several cases are presented which show good agreement with the theoretical findings. This is a versatile technique for near-field in situ interrogation of stratified composite media which provides for high resolution measurements

Unwanted Pregnancy and Its Risk Factors Among Pregnant Women in Tehran, Iran

Background: Unwanted pregnancies remain a main public health problem worldwide. In Iran, comparative studies on the risk factors of unwanted pregnancies and their effects on maternal health are rare. Objectives: This study was conducted to determine the risk factors of unwanted pregnancies and their impact on maternal behavior during pregnancy. Patients and Methods: This case-control study was carried out on 240 pregnant women who referred to the healthcare centers of Shahid Beheshti University of Medical Science for receiving routine prenatal care. Of the 240 women, 120 had unwanted pregnancies (case) and 120 had wanted pregnancies (control). Data collection was performed using a researcher-made questionnaire. The data were analyzed using chi-square tests, Fisher’s exact tests, t-tests, Mann Whitney U tests, odds ratios, and logistic regression analysis. Results: Compared to women with wanted pregnancies, those with unwanted pregnancies were more employed (23.3% vs. 12.5%, P = 0.006), had lower education levels (P = 0.016), had lower incomes (P = 0.009), had more children (1.30 ± 1.08 vs. 0.53 ± 0.67, P = 0.001), and had more traditional marriages (15% vs. 3.3%, P = 0.002). Also, women with unwanted pregnancies had significantly lower tendencies to do prenatal care (P = 0.002), had a higher tendency to abortion (P = 0.001), had higher previous abortion attempts (P = 0.001), and had higher levels of unhealthy behaviors (P = 0.017) compared to those with wanted pregnancies. Conclusions: Lower education and socioeconomic status, longer marriage duration, being employed, and unwilling of spouse were among the risk factors of unwanted pregnancies. These women are at high risk for unhealthy behaviors and have a higher tendency to abortion that consequently threatens their health

Microwave Diagnosis of Rubber Compounds

The results of a study investigating the dielectric properties of rubber compounds and their constituents in the frequency range of 5 to 24 GHz are presented. A completely filled short circuited waveguide technique was used to conduct these dielectric measurements. The influence of carbon black content in rubber was investigated for carefully prepared rubber samples. The results showed that for all frequencies, the dielectric constant increases as a function of increasing carbon black content. The variation of dielectric constant values decreases as frequency increases. The presence of curatives in uncured rubber samples was also detected, which indicates the sensitivity of microwaves to the chemical reaction triggered by curatives

Near-field millimeter - wave imaging of nonmetallic materials

A near-field millimeter-wave (mm-wave) imaging system has been designed and built in the 94-GHz range for on-line inspection of nonmetallic (dielectric) materials. The imaging system consists of a transceiver block coupled to an antenna that scans the material to be imaged; a reflector plate is placed behind the material. A quadrature IF mixer in the transceiver block enables measurement of in-phase and quadrature-phase components of reflected signals with respect to the transmitted signal. All transceiver components, with the exception of the Gunn-diode oscillator and antenna, were fabricated in uniform blocks and integrated and packaged into a compact unit (12.7 x 10.2 x 2.5 cm). The objective of this work is to test the applicability of a near-field compact mm-wave sensor for on-line inspection of sheetlike materials such as paper, fabrics, and plastics. This paper presents initial near-field mm-wave images of paper and fabric samples containing known artifacts

Open-path millimeter-wave spectroscopy in the 225--315 GHz range

This paper discusses the development of an open-path millimeter-wave (mm-wave) spectroscopy system in the 225--315 GHz atmospheric window. The new system is primarily a monostatic swept-frequency radar consisting of a mm-wave sweeper, hot-electron-bolometer or Schottky detector, and trihedral reflector. The heart of the system is a Russian backward-wave oscillator (BWO) tube that is tunable over 225--350 GHz. A mm-wave sweeper has been built with the BWO tube to sweep the entire frequency range within 1 s. The chemical plume to be detected is situated between the transmitter/receiver and the reflector. Millimeter-wave absorption spectra of chemicals in the plume are determined by measuring swept-frequency radar signals with and without the plume in the beam path. Because of power supply noise and thermal instabilities within the BWO structure over time, the BWO frequencies fluctuate between sweeps and thus cause errors in baseline subtraction. To reduce this frequency-jitter problem, a quasi-optical Fabry-Perot cavity is used in conjunction with the radar for on-line calibration of sweep traces, allowing excellent baseline subtraction and signal averaging. Initial results of the new system are given for open-path detection of chemicals

Determining bonding quality in polymer composites with a millimeter wave sensor

Microwave nondestructive testing (NDT) techniques offer alternative solutions to other conventional NDT methods. Microwave/millimeter wave (determined roughly to cover 0.3 to 300 GHz) techniques are particularly useful for examination of dielectric composite materials that their low dielectric losses provide good depth of penetration of electromagnetic radiation in this band. Limitations associated with conventional NDT techniques such as high frequency ultrasonic testing (UT), namely, large variations in elastic properties of low density composite materials cause interpretation of complex UT signals difficult. Further, criticality of coupling of transducer to the sample surface limits the use of such techniques for on-line applications. High frequency microwave (millimeter waves, 30--300 GHz) systems compared to their low frequency counterparts offer higher resolution and sensitivity to variations in dielectric properties of low-loss composites. Further, higher frequencies render utilization of more compact systems which are often important for practical applications. A millimeter wave sensor is described in this work which can be utilized for non-contact NDT of a wide range of thin-sheet dielectric composite materials either as a laboratory-based instrument or for on-line quality control applications. Experimental results are presented on noncontact measurement of bonding quality in polyethylene/carbon composite samples. The w-band monostatic sensor operates based on measurement of the reflection properties of the material under test, which are then used to determine the volumetric uniformity of the joint area. Preliminary experimental results indicate the potential for the use of this sensor in fabrication process control of low-loss dielectric composite materials