584 research outputs found

    Minimal Uncertainty in Momentum: The Effects of IR Gravity on Quantum Mechanics

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    The effects of the IR aspects of gravity on quantum mechanics is investigated. At large distances where due to gravity the space-time is curved, there appears nonzero minimal uncertainty Δp0\Delta p_{0} in the momentum of a quantum mechanical particle. We apply the minimal uncertainty momentum to some quantum mechanical interferometry examples and show that the phase shift depends on the area surrounded by the path of the test particle . We also put some limits on the related parameters. This prediction may be tested through future experiments. The assumption of minimal uncertainty in momentum can also explain the anomalous excess of the mass of the Cooper pair in a rotating thin superconductor ring.Comment: 8 pages, revised version accepted by PR

    Cancellation of soft and collinear divergences in noncommutative QED

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    In this paper, we investigate the behavior of non-commutative IR divergences and will also discuss their cancellation in the physical cross sections. The commutative IR (soft) divergences existing in the non-planar diagrams will be examined in order to prove an all order cancellation of these divergences using the Weinberg's method. In non-commutative QED, collinear divergences due to triple photon splitting vertex, were encountered, which are shown to be canceled out by the non-commutative version of KLN theorem. This guarantees that there is no mixing between the Collinear, soft and non-commutative IR divergences

    Assessment of extreme productivity of microalgae cultivated in the open air around neighborhoods of Isfahan City

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    The widespread use of microalgae in various fields of human activity including fishery generated a need of highly productive technologies of industrial production of microalgae biomass. In present paper, extreme productivity values of microalgae culturing system were assessed around neighborhoods of the Isfahan City in theory. It will amount to 37.90 g of dry weight (g. d. w.) per 1 m^2 of the illuminated reactor surface under condition that efficiency factor of photobiosynthesis equals to 5%. When photobiosynthetic efficiency is 15%, maximum values of productivity will be 113.71 g. d. w. per 1 m^2. Productivity of microalgae culturing system for its various orientations relative to the Sun at different photobiosynthetic efficiency was calculated on basis of simple model understandings regarding average caloric content of 1 g.d.w. of microalgae and the daily distribution of solar radiation which arrives at the surface of the Earth. If it is drown a curve of the third order (spline) through the points corresponding to days of the vernal (21 March) and autumnal (21 September) equinoxes and a summer solstice (22 June), the extreme (ideal) value of the yield will be 18.5 kg of dry biomass per square meter of illuminated surface (at photobiosynthetic efficiency of 0.15)

    Pre-stimulus alpha activity modulates face and object processing in the intra-parietal sulcus, a MEG study

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    Face perception is crucial in all social animals. Recent studies have shown that pre-stimulus oscillations of brain activity modulate the perceptual performance of face vs. non-face stimuli, specifically under challenging conditions. However, it is unclear if this effect also occurs during simple tasks, and if so in which brain regions. Here we used magnetoencephalography (MEG) and a 1-back task in which participants decided if the two sequentially presented stimuli were the same or not in each trial. The aim of the study was to explore the effect of pre-stimulus alpha oscillation on the perception of face (human and monkey) and non-face stimuli. Our results showed that pre-stimulus activity in the left occipital face area (OFA) modulated responses in the intra-parietal sulcus (IPS) at around 170 ms after the presentation of human face stimuli. This effect was also found after participants were shown images of motorcycles. In this case, the IPS was modulated by pre-stimulus activity in the right OFA and the right fusiform face area (FFA). We conclude that pre-stimulus modulation of post-stimulus response also occurs during simple tasks and is therefore independent of behavioral responses

    A novel approach of multimedia instruction applications in engineering education

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    Effective use of educational technology depends on knowledge of why and how to utilize technology to solve teaching and learning problems. The present study first conducts a systematic literature review of the limited studies undertaken on multimedia instruction applications for engineering education to critique the current status of knowledge in this area. The conventional qualitative content analysis method was employed for data analysis. The results highlighted the incompatibility of three basic educational elements i.e. engineering curriculum, educational resources and engineering students’ learning characteristics all of which posed major challenges in teaching and learning engineering courses. Multimedia instruction enhances engineering students’ understanding of engineering concepts, procedures, problems and solutions through direct visualization. Furthermore, it could indirectly assist students in achieving higher order learning levels and skills through enhancing or supporting educational resources and increasing students’ motivation. Mobile multimedia instruction and a student-generated multimedia learning approach to improve engineering education are suggested for future research

    Leaf Area, Fresh Weight and Dry Weight Prediction Models for Ornamental Plants Ficus benjamina (cv. Starlight)

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    Measurements of leaf growth indices namely leaf area, fresh weight and dry weight are of value in physiological studies and plant growth estimation. The use of prediction models to estimate leaf area, fresh weight and dry weight is simple, rapid and non-destructive. Several mathematical functions have been formulated for estimating leaf area, fresh weight and dry weight of various crops but almost there is no information for Ficus benjamina. This work was aimed to propose leaf area (LA), fresh weight (FW) and dry weight (DW) prediction models for Ficus benjamina (cv. Starlight) leafy ornamental pot plant using leaf length (L) and width (W). 1000 leaves were collected randomly from greenhouse grown plants and 700 of cuts were used for prediction models. LA was measured with a digital area meter (DELTA-T, Co. Durham, UK), related FW and DW also were weighted and leaf dimensions were determined by the ruler. For each studying growth index LA, FW and DW the predictive abilities of three regression equations (linear, polynomial and power) were compared with different independent variables for each equation. Leaf length × width provided a good estimation of leaf area and fresh weight of the leaves of Ficus benjamina. It was also concluded that leaves the dry weight of Ficus benjamina can be estimated or simulated as a power function of L×W or L+W with reasonable accuracy. Moreover, a reasonable relationship between leaf fresh weight and leaf area was found too

    Análisis del genoma ovino para la identificación de QTL con influencia sobre caracteres de morfología mamaria: resultados preliminares

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    Ponencia publicada en ITEA, vol.104El objetivo del presente estudio es la localización de regiones genómicas con influencia sobre caracteres de morfología mamaria en ganado ovino, utilizando la metodología de genome scan, o barrido genómico. Con este fin, se ha analizado una población comercial de ganado ovino de raza Churra, organizada en un diseño hija compuesto por 8 familias de medio-hermanas. Un total de 182 marcadores genéticos, distribuidos uniformemente a lo largo del genoma ovino autosómico, fueron genotipados en la población objeto de estudio. Como medidas cuantitativas se utilizaron las desviaciones calculadas para los caracteres de morfología mamaria considerados en el programa de mejora genética de la raza ovina Churra: inserción de la ubre, posición de los pezones, tamaño de los pezones, profundidad y forma global de la ubre. Para la identificación de los QTL se realizó un análisis de regresión de los fenotipos con marcadores flanqueantes. El análisis del genoma para el conjunto de la población permitió la identificación de 11 regiones asociadas con estos caracteres, al nivel chromosome-wise, en los siguientes cromosomas: 4, 6, 7, 8, 10, 14, 15, 20, 22, 23 y 26. Para las asociaciones significativas se debe realizar una verificación previamente al abordaje del mapeo fino.Analysing the ovine genome to detect QTL for mammary morphology: preliminary results The objective of this work was the identification of chromosomal regions influencing udder morphology traits in dairy sheep by using the genome scan approach. For this purpose, we have analyzed a commercial population of Spanish Churra sheep organized according a daughter design, which included 8 half-sib families. A total of 182 genetic markers, evenly distributed along the ovine autosome, were genotyped in the studied population. As quantitative measurements for the analysis, we used the yield deviations calculated for each of the udder traits considered in the breeding program of Churra sheep: udder attachment, teat position and teat size, udder depth and udder shape. A multimarker regression analysis was used to detect QTL. The whole genome analysis allowed the identification of 11 chromosome-wide significant regions associated with the traits analyzed in the following chromosomes: 4, 6, 7, 8, 10, 14, 15, 20, 22, 23 y 26. Confirmation of the detected effects is required before attempting future fine mapping studies on these regions

    Disseminated Leishmaniasis Caused by Leishmania tropica in a Puppy from Karaj, Central Iran

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    A 5-month old puppy with muco-cutaneous lesions in the chin, around lips and eyes was examined physically and microscopically for leishmaniasis. Muco-cutaneous lesions containing a large number of amastigotes of Leishmania spp. were observed. Amastigotes were also detected in liver and spleen of the puppy. The animal was positive with Dipstick rK39 kit and high level of anti-Leishmania antibodies was detected by direct agglutination test (DAT). DNA, Using PCR-RFLP technique extracted from cultured Leishmania promastigotes and L. tropica was identified. This is the first report of concurrent mucosal and visceral involvement of L. tropica in a puppy from Iran
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