154 research outputs found

    Zero-Delay Joint Source-Channel Coding in the Presence of Interference Known at the Encoder

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    Zero-delay transmission of a Gaussian source over an additive white Gaussian noise (AWGN) channel is considered in the presence of an additive Gaussian interference signal. The mean squared error (MSE) distortion is minimized under an average power constraint assuming that the interference signal is known at the transmitter. Optimality of simple linear transmission does not hold in this setting due to the presence of the known interference signal. While the optimal encoder-decoder pair remains an open problem, various non-linear transmission schemes are proposed in this paper. In particular, interference concentration (ICO) and one-dimensional lattice (1DL) strategies, using both uniform and non-uniform quantization of the interference signal, are studied. It is shown that, in contrast to typical scalar quantization of Gaussian sources, a non-uniform quantizer, whose quantization intervals become smaller as we go further from zero, improves the performance. Given that the optimal decoder is the minimum MSE (MMSE) estimator, a necessary condition for the optimality of the encoder is derived, and the numerically optimized encoder (NOE) satisfying this condition is obtained. Based on the numerical results, it is shown that 1DL with nonuniform quantization performs closer (compared to the other schemes) to the numerically optimized encoder while requiring significantly lower complexity

    Gaussian multiple access channels with one-bit quantizer at the receiver

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    The capacity region of a two-transmitter Gaussian multiple access channel (MAC) under average input power constraints is studied, when the receiver employs a zero-threshold one-bit analogue-to-digital converter (ADC). It is proven that the input distributions of the two transmitters that achieve the boundary points of the capacity region are discrete. Based on the position of a boundary point, upper bounds on the number of the mass points of the corresponding distributions are derived. Furthermore, a lower bound on the sum capacity is proposed that can be achieved by time division with power control. Finally, inspired by the numerical results, the proposed lower bound is conjectured to be tight

    Karyotyping and number of chromosomes of silver carp (Hypophthalmichthys molitrix)

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    Karyotype and number of chromosomes of silver carp (Hypophthalmichthys molitrix) were determined by using tissue-squashing method and gimsa staining. In this experiment 80 larvae and 10 fingerlings (weighting 1-8 g) were examined and totally 30 chromosomal slides were prepared. The obtain results indicated that the number of chromosomes in this species was found 2n=48 (with 88 chromosomal arms). Consist of 6 pairs metacentric (M), 14 pairs submetacentric (SM) and 4 pairs of Acrocentric (A). The karyotype formula can be stated as: (6M + 14SM + 4A)

    Evaluating the potential of a bivalve species from the intertidal zone of the Persian Gulf for biomonitoring of trace elements using a nondestructive analytical method

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    This study was carried out in order to evaluate the potential of the soft and hard tissues of a bivalve species (Callista umbonella) for biomonitoring of different elements in coastal areas of northern part of the Persian Gulf as well as to assess the possible use of PIXE (Proton Induced X-ray Emission) method in this regard. The bivalve specimens and surficial sediment samples were collected from three sampling sites located on the intertidal zone of Hormozgan Province in August 2014. Concentrations of the elements were determined using the non-destructive method, PIXE. Assessment of total organic matter (TOM) and grain size were also carried out in the sediment samples. Based on the results, of the 17 elements measured in the soft tissues, (Al, Br, Ca, Cl, Cr, Fe, K, Mg, Mn, Na, O, P, S, Si, Sr, Ti and Zn) in the case of P, Fe, Br and O significant differences were observed between the sampling sites. Of the 14 elements measured in the shells (Al, Br, Ca, Cl, Cu, Fe, Mg, Mn, Na, K, O, S, Si and Sr) only in the case of Si significant differences between the sites could be detected and of the 14 elements measured in the surface sediments (Al, Ca, Cl, Cr, Fe, Mg, Mn, Na, Ni, K, O, S, Si and Ti) in the case of Na, Mg, S, Cl, K , Ca, Ti and Fe significant differences were found between the sites. In each of the above cases, order of the elements accumulation was assessed and possible causes of the differences evaluated. In order to classify the elements based on their levels in the sediments, soft tissues and shells the multivariate analyses (principal component analysis and cluster analysis) were used. According to the gained results, C. umbonella can be considered as a potential candidate species for biomonitoring of a number of elements in the coastal area of the Persian Gulf

    The Effect of Different Types of Coating and Packaging on the Physical Properties of Persimmon Fruit under Load

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    Since persimmon is a pressure-sensitive fruit and it is difficult to store this fruit in warehouses, in this research, an attempt has been made to examine the parameters affecting the reduction of changes in its physical properties. The samples were loaded at 150 and 250 N, three types of foam container packaging with polyolefin film, polyethylene-terephthalate, and ordinary box, and four types of polyamine putrescine coating with concentrations of 1 and 2 mM, distilled water and uncoated. Properties such as Physiological Weight Loss, volume, and the density of persimmon fruit, as well as the firmness of this fruit in the prepost-storage stage were examined. The results showed, the highest firmness was obtained in the treatment of putrescine at a concentration of 1 mM and a foam container with polyethylene film with a value of 6.5 N, which was almost three times the firmness of uncoated fruits. The lowest Physiological Weight Loss, volume, and density were obtained in the same type of coating and packaging. The values of these parameters were 2.458%, 1.82, and 0.833%, respectively, compared to the first day of storage. Overall, the use of polyamine treatment showed a significant effect on changes in the physical properties of persimmon fruit, and foam containers with polyolefin film emerged as the optimal packaging option, resulting in the least amount of change among the different types of packaging used

    On the Lubricity and Comparative Life Cycle of Biobased Synthetic and Mineral Oil Emulsions in Machining Titanium Ti-6Al-4V at Low Cutting Speed

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    The paper discusses an instrumented tapping test method using a CNC machine tool to compare the lubricity of MWFs by cutting threads in a Ti-6Al-4V alloy at low speed. The method uses a spiral flute tap size typical of industrial practice. A soft synchronous tap holder and spindle mounted dynamometer were incorporated on the machine to measure torque and thrust force. The tapping test method was demonstrated on three groups of MWFs that were commercially available and classified by ASTM E2523-13:2018. The method developed stable results free of chip clogging in tool flutes which could otherwise mask their comparative lubricity. The fully synthetic (FS) group displayed the best lubricity and within this group the FS from renewables (FS-bio) was the best overall. The method was shown to be effective in mitigating biasing effects on lubricity performance due to the generous tool chamfer angle tolerance and was practical and economical to implement. The significance of the results is discussed enabling an understanding of friction effects in tapping using a soft synchronous tap holder. A life cycle assessment of each MWF group found total Greenhouse Gas emitted from the FS group was 17% of the hydrocarbon group whilst FS-bio emitted just 7%

    Identification of methionine synthase (Sal k 3), as a novel allergen of Salsola kali pollen

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    Salsola kali pollen is a common cause of pollinosis during summer and early fall in desert and semi-desert regions. The aim of this study was the identification and characterization of Sal k 3, a new allergen from S. kali pollen. S. kali pollen extract was fractionated by SDS-PAGE and the allergenic profile was determined by IgE-immunoblotting using twelve S. kali allergic patients. Protein identification was carried out by the means of mass spectrometry. Using degenerated primers, two DNA fragments encoding N- and C-terminal domain of Sal k 3 were amplified by PCR, then cloned into the PTZ57R/T vector and sequenced. The open reading frame of Sal k 3 fragments were subcloned in the pET-32b(+) vector, expressed in E. coli, and purified by Ni2+ affinity chromatography. The IgE-binding capacity of rSal k 3 fragments was then studied by IgE-immunoblotting, inhibition assays, and skin prick tests. A 45-kDa allergen was identified as a fragment of the cobalamin-independent methionine synthase (MetE) by mass spectrometry and was detected in the sera of 8/12 (66.6) of S. kali allergic patients. Moreover, inhibition assays demonstrated that the purified rSal k 3 fragments were similar to their counterparts in the crude extract. Sal k 3 represents a new allergen of S. kali pollen and seems to be an important allergenic compound in S. kali pollen. © 2010 Springer Science+Business Media B.V

    Molecular Cloning and Expression of Cro s 1: an Occupational Allergen from Saffron Pollen (Crocus sativus)

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    Background: The cultivation of saffron is expanding through the southeast of Iran, and allergy to saffron pollen occurs in workers involved in processing this plant. We aimed to clone, sequence and express a major allergen involved in saffron pollen allergy, and to compare the recombinant with the natural allergen. Methods: The N-terminal amino acid sequence of Cro s 1, an allergen from saffron pollen, was determined after immunoblotting. The cDNA encoding for this allergen was cloned by PCR utilizing a primer based on the N-terminal amino acid sequence. Recombinant Cro s 1 (rCro s 1) was expressed as a soluble protein in Pichia pastoris and purified to homogeneity by gel filtration. Inhibition of IgE binding to rCro s 1 by pollen extract was analyzed by ELISA. Results: The allergen Cro s 1 was identified from saffron pollen extracts and cloned by PCR. Cro s 1 cDNA defined an acidic polypeptide with homology to pollen proteins from Chenopodium album and Ligastrum vulgaris. The rCro s 1 was expressed in P. pastoris at 28 mg/l. Saffron pollen extract inhibited the binding of patient serum IgE to rCro s 1. Conclusion: We identified and cloned the first Crocus sativus pollen allergen. rCro s 1 cDNA shows a very high homology with Che a 1, the major allergen of lamb's-quarter, Chenopodium album, Caryophyllales, pollen (97%). Cro s 1 is a useful tool for specific diagnosis and structural studies of occupational allergy to saffron
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