Effects of scenery, lighting, glideslope, and experience on timing the landing flare.

This study examined three visual strategies for timing the initiation of the landing flare based on perceptions of either: (a) a critical height above ground level; (b) a critical runway width angle (Ψ); or (c) a critical time-to-contact (TTC) with the runway. Visual displays simulated landing approaches with trial-to-trial variations in glideslope, lighting, and scene detail. Twenty-four participants (8 private pilots, 8 student pilots, and 8 nonpilots) were instructed to initiate the flare when they perceived that their TTC with the runway (30 m wide by 840 m long) had reached a critical value of 2 seconds. Our results demonstrated a significant effect of flight experience on flare timing accuracy and dominance of the height-based strategy over the runway-width-angle and TTC-based strategies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A 12-GHz silicon bipolar dual-conversion receiver for digital satellite applications

A 12-GHz monolithic silicon bipolar receiver for digital video broadcasting via satellite (DVB-S) is presented. The receiver is based on a dual-conversion superheterodyne architecture that employs a single LO integrated in the same die. To comply with the stringent LO phase noise requirement of -101 dBc/Hz at 100 kHz offset from the carrier, an innovative VCO topology, based on a three-layer monolithic transformer, was used. The VCO exhibits a phase noise of -102 dBc/Hz at 100 kHz offset from a 5.3-GHz carrier and a 1.1-GHz tuning range. At 12 GHz, the conversion gain is 33.6 dB, the single-sideband noise figure is 5.9 dB and the output IP3 is +16 dBm. This work reports the first 12-GHz DVB-S monolithic receiver integrated in a low-cost silicon bipolar technology.     

Determination of methotrexate in untreated body fluids by micellar liquid chromatography

A fast and sensitive method for determination of the antineoplastic drug methotrexate in untreated serum and urine is described. Reversed-phase liquid chromatography with sodium dodecyl sulfate (SDS) micellar mobile phase has been used with direct sample injection. Changes in mobile phase variables such as SDS concentration and/or pH profoundly affected drug retention. Recovery was quantitative and the detection limit (90 nM for a 20 microL sample size) was below the range normally monitored. Multichannel UV detection provided strong evidence regarding peak purity and peak identity.     

Switched capacitor compatible minimum-maximum function

A new block for the implementation of the function is presented. It is based on structures commonly used in SC circuits and is fully compatible with this approach. The circuit was realised in a 1.2 μm standard CMOS technology. The experimental results show good agreement with the predicted results     

Using context to improve the effectiveness of segmentation and targeting in e-commerce

In e-commerce, where competition is tough and customers’ preferences can change quickly, it is crucial for companies to segment customers and target marketing actions effectively. The process of segmentation and targeting is effective if the customers grouped into the same segment show the same behavior and reaction to marketing campaigns. However, the link between segmentation and targeting is often missing. Some research contributions have recently addressed this issue, by proposing approaches to build customer behavior models in each segment. However customers’ behavior can change with the context, such as in many e-commerce business applications. In these cases, building contextual models of behavior would provide better predictive performance and, in turn, better targeting. However, the problem of including context in a segmentation model and building predictive behavior model of each segment consistently is still an open issue. This research aims at providing an answer to the following research issue: how to include context in a segmentation model in order to build an effective predictive model of customer behavior of each segment. To this aim we identified three different approaches and compared them by a set of experiments across several settings. The first result is that one of the three approaches dominates the others in certain conditions in our experiments. Another important result is that the most accurate approach is not always the most efficient from a managerial perspective.     

High-dynamic-range variable gain amplifier with temperature compensation and linear-in-decibel gain control

A novel intermediate-frequency variable-gain amplifier for wideband code-division multiple access transmitters is presented. The circuit includes a compensation technique for parasitic coupling, which allows a high dynamic range of 85 dB to be attained while using a single variable-gain stage. Temperature compensation and decibel-linear characteristic are achieved by means of a control circuit providing a lower than /spl plusmn/1.5 dB gain error over full temperature and gain ranges.     

Biological effects and photodegradation by TiO(2) of terpenes present in industrial wastewater

The aim of this work was to study the biological effects of four monoterpenes, i.e. α-pinene, β-pinene, 3-carene and D-limonene present in the wastewater of a citrus transformation factory. The study was carried out by exposing V79 Chinese hamster cells to single terpene or to the mixture of four terpenes at concentrations corresponding to those in the wastewater evaluated by head space solid phase micro extraction and gas chromatography (HS-SPME-GC) analyses. Treatments with single or combined terpenes similarly affected cell vitality, but only the combined treatments induced the 6-thioguanine resistant mutants. Moreover the photocatalytic degradation of the four terpenes was successfully achieved with the photocatalyst TiO(2) Degussa P25 in both the actual effluent and in synthetic solutions.     

A Ku-band monolithic receiver for DVB-S applications

Despite the incessant progress observed in fixed and wireless terrestrial communication networks, satellite systems remain an appealing solution for broadcasting, point-to-point, and multicasting telecommunications, because of undemanding customer equipment and wide coverage capability. In this scenario, digital video broadcasting via satellite (DVB-S) is recognized as one of the main market-attractive telecommunication fields. Up to now, expensive discrete GaAs HEMT or FET devices have been used to build up circuitry for satellite applications at Ku-band. This article presents the first 12-GHz monolithic receiver for DVB-S applications, implemented in a low-cost silicon bipolar technology. The receiver is based on a superheterodyne architecture, employing a fully integrated LO. To comply with the severe LO phase noise requirement of -101 dBc/Hz at a 100 kHz offset from the carrier, an innovative VCO topology was used implementing a three-metal-layer integrated transformer. The performance parameters of the integrated receiver fulfill DVB-S standard specifications.     

Low voltage folded-mirror mixer

A low-voltage mixer is proposed which uses an RF voltage-to-current converter based on a folded current mirror. Gain, linearity, and frequency performance similar to a traditional high-voltage mixer are achieved with a 1.5-V power supply. Moreover, correct behaviour with a supply voltage as low as 1 V was also simulated