Gaze-dependent topography in human posterior parietal cortex.

The brain must convert retinal coordinates into those required for directing an effector. One prominent theory holds that, through a combination of visual and motor/proprioceptive information, head-/body-centered representations are computed within the posterior parietal cortex (PPC). An alternative theory, supported by recent visual and saccade functional magnetic resonance imaging (fMRI) topographic mapping studies, suggests that PPC neurons provide a retinal/eye-centered coordinate system, in which the coding of a visual stimulus location and/or intended saccade endpoints should remain unaffected by changes in gaze position. To distinguish between a retinal/eye-centered and a head-/body-centered coordinate system, we measured how gaze direction affected the representation of visual space in the parietal cortex using fMRI. Subjects performed memory-guided saccades from a central starting point to locations “around the clock.” Starting points varied between left, central, and right gaze relative to the head-/body midline. We found that memory-guided saccadotopic maps throughout the PPC showed spatial reorganization with very subtle changes in starting gaze position, despite constant retinal input and eye movement metrics. Such a systematic shift is inconsistent with models arguing for a retinal/eye-centered coordinate system in the PPC, but it is consistent with head-/body-centered coordinate representations

A Broadband UHF Tag Antenna For Near-Field and Far-Field RFID Communications

The paper deals with the design of passive broadband tag antenna for Ultra-High Frequency (UHF) band. The antenna is intended for both near and far fields Radio Frequency Identification (RFID) applications. The meander dipole tag antenna geometry modification is designed for frequency bandwidth increasing. The measured bandwidth of the proposed broadband Tag antenna is more than 140 MHz (820–960 MHz), which can cover the entire UHF RFID band. A comparison between chip impedance of datasheet and the measured chip impedance has been used in our simulations. The proposed progressive meandered antenna structure, with an overall size of 77 mm × 14 mm × 0.787 mm, produces strong and uniform magnetic field distribution in the near-field zone. The antenna impedance is matched to common UHF chips in market simply by tuning its capacitive and inductive values since a perfect matching is required in the antenna design in order to enhance the near and the far field communications. Measurements confirm that the designed antenna exhibits good performance of Tag identification for both near-field and far-field UHF RFID applications

Temporal integration in structure from motion

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Effect of low-pressure storage on the quality of green capsicums (<i>Capsicum annum L.</i>)

Green capsicums (Capsicum annum L.) were stored under low pressure (4 kPa) at 10°C for 5 and 11 days with 100% RH. The results showed that the incidence of stem decay under low pressure storage for 5 and 11 days and storage at ambient atmosphere at 20°C for three days lower compared to fruits that were stored at regular atmosphere at 10°C. Fruit that had been stored at low pressure at 10°C had no symptoms of flesh rots for up to 11 days, whilst fruit which had been stored at regular atmosphere at 10°C had 6% flesh rots after 11 days storage at 10°C.There was no difference in flesh firmness and colour retention between fruits stored at low pressure and regular pressure at 10°C. Capsicums stored at low pressure had higher overall acceptability compared to fruit that were stored at regular atmosphere at 10°C. These results demonstrate the potential of low pressure storage as an effective technique to manage capsicum fruit quality, however there was no additional benefit when fruits were stored at low pressure for more than 5 days

The application of low pressure storage to maintain the quality of zucchinis

Zucchini (Cucurbita pepo var. cylindrica) were stored at low pressure (4 kPa) at 10°C at 100% relative humidity for 11 days. Fruit quality was examined upon removal and after being transferred to normal atmosphere (101 kPa) at 20°C for three days. Zucchinis stored at low pressure exhibited a 50% reduction in stem-end browning compared with fruit stored at atmospheric pressure (101 kPa) at 10°C. The benefit of low pressure treatment was maintained after the additional three days storage at normal atmospheric pressure at 20°C. Indeed, low pressure treated fruit transferred to regular atmosphere 20°C for three days possessed a significantly lower incidence of postharvest rot compared to fruit stored at regular atmospheric pressure at 10°C. Zucchinis stored at low pressure showed higher levels of acceptability (28% and 36%, respectively) compared to fruit stored at regular atmospheres at 10°C for both assessment times.<br/

Combined postharvest UV-C and 1-methylcyclopropene (1-MCP) treatment, followed by storage continuously in low level of ethylene atmosphere improves the quality of Tahitian limes

The green Tahitian limes (Citrus latifolia) were exposed to 7.2 kJ m−2 UV-C and 0.5 μL L−1 1-methylcyclopropene (1-MCP) treatments both separately and in combination. After treatment, fruit were stored in ethylene free (i.e. air containing &lt; 0.005 μL L−1) or 0.1 μL L−1 ethylene at 20 °C and 100% RH. The results showed that UV-C treatment delayed skin degreening and reduced endogenous ethylene production compared to untreated control fruit, however these effects reduced over the storage time. As expected, 1-MCP inhibited ethylene production, reduced calyx abscission and retained peel greenness during the storage. Both of the combination treatments, 1-MCP + UV-C and UV-C + 1-MCP reduced endogenous ethylene production and delayed skin yellowing. In all treatments, UV-C and 1-MCP resulted in lower fruit respiration rates than untreated control fruit, however this effect diminished during 7 and 14 days storage for fruits stored in air and 0.1 μL L−1 ethylene atmosphere, respectively. There was no difference in weight loss, SSC, TA and SSC/TA ratio between the treatments and storage conditions. The results suggest that a pre-storage UV-C treatment, followed by storage at low level of ethylene improves the quality of limes, with the additional improvement when combined with 1-MCP treatment prior or after UV-C irradiation

Optimizing a sustainable ultrasound assisted extraction method for the recovery of polyphenols from lemon by-products:comparison with hot water and organic solvent extractions

Response surface methodology (RSM) based on a three-factor and three-level Box–Behnken design was employed for optimizing the aqueous ultrasound-assisted extraction (AUAE) conditions, including extraction time (35–45 min), extraction temperature (45–55 °C) and ultrasonic power (150–250 W), for the recovery of total phenolic content (TPC) and rutin from lemon by-products. The independent variables and their values were selected on the basis of preliminary experiments, where the effects of five extraction parameters (particle size, extraction time and temperature, ultrasonic power and sample-to-solvent ratio) on TPC and rutin extraction yields were investigated. The yields of TPC and rutin were studied using a second-order polynomial equation. The optimum AUAE conditions for TPC were extraction time of 45 min, extraction temperature of 50 °C and ultrasonic power of 250 W with a predicted value of 18.10 ± 0.24 mg GAE/g dw, while the optimum AUAE conditions for rutin were extraction time of 35 min, extraction temperature of 48 °C and ultrasonic power of 150W with a predicted value of 3.20 ± 0.12 mg/g dw. The extracts obtained at the optimum AUAE conditions were compared with those obtained by a hot water and an organic solvent conventional extraction in terms of TPC, total flavonoid content (TF) and antioxidant capacity. The extracts obtained by AUAE had the same TPC, TF and ferric reducing antioxidant power as those achieved by organic solvent conventional extraction. However, hot water extraction led to extracts with the highest flavonoid content and antioxidant capacity. Scanning electron microscopy analysis showed that all the extraction methods led to cell damage to varying extents

Impact of different solvents on the recovery of bioactive compounds and antioxidant properties from lemon (Citrus limon L.) pomace waste

The effects of different solvents on the recovery of (i) extractable solids (ES), (ii) total phenolic compounds (TPC), (iii) total flavonoid content (TFC), (iv) vitamin C, and (v) antioxidant activity from lemon pomace waste were investigated. The results revealed that solvents significantly affected the recovery of ES, TPC, TFC, and antioxidant properties. Absolute methanol and 50% acetone resulted in the highest extraction yields of TPC, whereas absolute methanol resulted in the highest extraction of TFC, and water had the highest recovery of vitamin C. 50% ethanol, and 50% acetone had higher extraction yields for TPC, and TFC, as well as higher antioxidant activity compared with their absolute solvents and water. TPC and TFC were shown to be the major components contributing to the antioxidant activity of lemon pomace

Screening the effect of four ultrasound-assisted extraction parameters on hesperidin and phenolic acid content of aqueous citrus pomace extracts

Polyphenols of citrus by-products, due to their antioxidant and antimicrobial activities, could be valorized by pharmaceutical and food industries, adding a value to the citrus processing companies. A number of studies have investigated the effect of ultrasound-assisted extraction (UAE) conditions on the recovery of phenolics derived from citrus waste using both organic solvents or mixed aqueous solvent systems. To maximize efficiency, UAE conditions should be tailored to the physical parameters of the solvent(s) employed. The aim of this study was to investigate the effect of four UAE parameters: particle size (1.40–2.80 mm), extraction time (10–60 min), extraction temperature (23–50 °C) and ultrasonic power (150–250 W) on the simultaneous recovery of p-coumaric acid, caffeic acid, chlorogenic acid, and hesperidin from citrus waste using pure water as a solvent. High-performance liquid chromatography (HPLC) was employed for the identification and quantification of the cited compounds. Particle size was determined to be an important parameter affecting compound recovery, with the exception of chlorogenic acid. A particle size of 1.40 mm resulted in the highest recovery of p-coumaric and caffeic acids (0.25 and 0.58 mg/g, respectively), while higher hesperidin yields were achieved from the particle sizes of 2.00 and 1.40 mm (6.44 and 6.27 mg/g, respectively). Extraction temperature significantly affected only the recovery of the flavanone glycoside (P&lt;0.05). As the extraction temperature increased from 30 to 50 °C the recovery of hesperidin increased from 6.59 to 7.84 mg/g, respectively. Neither extraction time nor ultrasonic power significantly affected the recovery of any individual phenolic compound