A study on Cryptosporidium contamination in lettuce collected from different areas in Shiraz

زمینه و هدف: کریپتوسپوریدیوم، یکی از انگل های مشترک انسان و دام با میزبان های متنوع، به عنوان یک عامل بیماریزا در انسان به ویژه در افراد دچار سرکوب یا نقص ایمنی به خوبی شناخته شده است. از نظر همه گیر شناسی راه های انتقال کریپتوسپوریدیوم شامل انتقال اووسیست مقاوم از راه آب آشامیدنی، سبزیجات و غذا است. هدف از مطالعه ی حاضر،‌ مقایسه میزان آلودگی کریپتوسپوریدیایی کاهوهای عرضه شده (به عنوان یکی از منابع آلودگی انسان) در مناطق مختلف شهر شیراز است. روش بررسی: در این مطالعه توصیفی-تحلیلی 200 نمونه کاهو (هر نمونه 500 گرم) از چهار منطقه مختلف (کاهوی زرقان، کفترک، جهرمی و اهواز) در فصول بهار و تابستان سال 1385 مورد بررسی قرار گرفت. همه نمونه ها با رنگ آمیزی زیل نلسون اصلاح شده رنگ آمیزی شده و تعداد اووسیست در هر نمونه مورد شمارش قرار گرفت. اطلاعات به دست آمده با استفاده از آزمون های آماری مربع کای و آزمون ناپارامتری کروسکال والیس مورد تجزیه و تحلیل قرار گرفت. یافته ها: از 200 نمونه، 47 نمونه (5/23) آلوده بودند. مقایسه ی آماری نتایج نشان داد که بجز کاهوی جهرم که آلودگی آن در بهار بیش از تابستان بود (05/0

Orthogonal Frequency Division Multiplexed Quantum Key Distribution in The Presence of Raman Noise

In this paper, we investigate the performance of orthogonal frequency division multiplexed quantum key distribution (OFDM-QKD) in an integrated quantum-classical wavelength-division-multiplexing system. The presence of an intense classical signal alongside the quantum one generates Raman background noise. Noise reduction techniques should, then, be carried out at the receiver to suppress this crosstalk noise. In this work, we show that OFDM-QKD enables efficient filtering, in time and frequency domains, making it an attractive solution for the high-rate links at the core of quantum-classical networks

Optimal Wavelength Allocation in Hybrid Quantum-Classical Networks

An efficient algorithm for optimal allocation of wavelengths in a hybrid dense-wavelength-division-multiplexing system, carrying both quantum and classical data, is proposed. The transmission of quantum bits alongside intense classical signals on the same fiber faces major challenges arising from the background noise generated by classical channels. Raman scattering, in particular, is shown to have detrimental effects on the performance of quantum key distribution systems. Here, by using an optimal wavelength allocation technique, we minimize the Raman induced background noise on quantum channels, hence maximize the achievable secret key generation rate for quantum channels. It turns out the conventional solution that the optimal arrangement would involve splitting the spectrum into only two bands, one for quantum and one for classical channels, is only a suboptimal one. We show that, in the optimal arrangement, we might need several quantum and classical bands interspersed among each other

Crosstalk Reduction in Hybrid Quantum-Classical Networks

In this paper, we propose and investigate several crosstalk reduction techniques for hybrid quantum-classical dense-wavelength-division-multiplexing systems. The transmission of intense classical signals alongside weak quantum ones on the same fiber introduces some crosstalk noise, mainly due to Raman scattering and nonideal channel isolation, that may severely affect the performance of quantum key distribution systems. We examine the conventional methods of suppressing this crosstalk noise, and enhance them by proposing an appropriate channel allocation method that reduces the background crosstalk effectively. Another approach proposed in this paper is the usage of orthogonal frequency division multiplexing, which offers efficient spectral and temporal filtering features

A Virtual Conversational Agent for Teens with Autism: Experimental Results and Design Lessons

We present the design of an online social skills development interface for teenagers with autism spectrum disorder (ASD). The interface is intended to enable private conversation practice anywhere, anytime using a web-browser. Users converse informally with a virtual agent, receiving feedback on nonverbal cues in real-time, and summary feedback. The prototype was developed in consultation with an expert UX designer, two psychologists, and a pediatrician. Using the data from 47 individuals, feedback and dialogue generation were automated using a hidden Markov model and a schema-driven dialogue manager capable of handling multi-topic conversations. We conducted a study with nine high-functioning ASD teenagers. Through a thematic analysis of post-experiment interviews, identified several key design considerations, notably: 1) Users should be fully briefed at the outset about the purpose and limitations of the system, to avoid unrealistic expectations. 2) An interface should incorporate positive acknowledgment of behavior change. 3) Realistic appearance of a virtual agent and responsiveness are important in engaging users. 4) Conversation personalization, for instance in prompting laconic users for more input and reciprocal questions, would help the teenagers engage for longer terms and increase the system's utility

Optimum Functions for Radial Wires of Monopole Antennas with Arbitrary Elevation Angles

Monopole antennas on the earth usually use ground screen with simple radial wires to improve their radiation performance. The number of radials,N, is usually considered a constant in the screen. This paper studies the effect of changing N and considering it as a function of distance, ρ, from the monopole using a simple and yet a fast method. The function N(ρ) is optimized for different beam angles of an HF monopoleantenna. The theoretical functions are converted to practical functions to be formed using meandered lines. Practicable calculated results are validated bymethod of moments. Furthermore it is shown that for low angle radiation aconstant N(ρ) with optimized radius of the ground screen is the best choice. The results can be used for higher frequencies, i.e. VHF and UHF frequency bands as well