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At least 199 records · Page 11Linked to original sources
PubMed2005

Performance improvement of optical wireless communication through fog with a decision feedback equalizer.

Optical wireless communication (OWC) systems use the atmosphere as a propagation medium. However, a common problem is that from time to time moderate cloud and fog emerge between the receiver and the transmitter. These adverse weather conditions impose temporal broadening and power loss on the optical signal, which reduces the digital signal-to-noise ratio (DSNR), produces significant intersymbol interference (ISI), and degrades the communication system's bit error rate (BER) and throughput. We propose and investigate the use of a combined adaptive bandwidth mechanism and decision feedback equalizer (DFE) to mitigate these atmospheric multipath effects. Based on theoretical analysis and simulations of DSNR penalties, BER, and optimum system bandwidths, we show that a DFE improves the outdoor OWC system immunity to ISI in foggy weather while maintaining high throughput and desired low BER.

Journal Article↗
PubMed1993

Bronchial responsiveness to ultrasonic fog in occupational asthma due to toluene diisocyanate.

To determine the validity of ultrasonic nebulization of distilled water (UNDW, "fog") in comparison with methacholine challenge, in the assessment of toluene diisocyanate (TDI) asthma, we evaluated 75 subjects exposed to TDI with work-related respiratory symptoms. Subjects were submitted to bronchial challenge with methacholine at first, thereafter to UNDW inhalation and to specific challenge with TDI. The diagnosis of TDI-asthma was made in 30 of 75 patients (40 percent) who developed a bronchoconstrictive response to the specific challenge (reactors). Sensitivity and specificity of UNDW alone, methacholine alone, and of the combination of the two tests were determined with the results of the specific challenge with TDI as the "gold standard." Both frequency and severity of bronchoconstrictive response to UNDW (FEV1 decrease > or = 15 percent) and the degree (PD15 FEV1) and frequency of bronchial hyperresponsiveness to methacholine were significantly higher in TDI reactors than in nonreactors. The UNDW had higher specificity (82.2 percent vs 51.1 percent) but lower sensitivity (40 percent vs 76.7 percent) than methacholine. The combination in parallel (positivity of any of the two challenges) of methacholine and UNDW challenge did not change sensitivity to a great extent (80 percent vs 76.7 percent), whereas combination in series (positivity of both challenges) had considerably greater specificity (86.7 percent vs 51.1 percent) than methacholine alone. We conclude that in the assessment of TDI-asthma, the validity of UNDW challenge alone is limited since it is insufficiently sensitive. Instead, combining UNDW and methacholine challenge when methacholine is positive improves our ability in identifying subjects with TDI-asthma diagnosed with the specific challenge. This procedure constitutes a first objective confirmation of a suggestive history of TDI-asthma that is useful for clinical purposes. However, especially for medicolegal purposes, the definitive diagnosis requires the specific challenge.

Adult↗
PubMed2001

Indoor thermal fogging application of pesguard FG 161, a mixture of d-tetramethrin and cyphenothrin, using portable sprayer against vector mosquitoes in the tropical environment.

Indoor bioefficacy of the thermal fogging application of Pesguard FG 161, a formulation containing both knockdown and killing agents (active ingredient [AI]: d-tetramethrin 4% [w/w] and cyphenothrin 12% [w/w]) was compared with Resigen5 (AI: s-bioallethrin 0.8% [w/w], permethrin 125/75] 18.7% [w/w], and piperonyl butoxide 16.8% [w/w]), another pyrethroid formulation, as larvicides and adulticides against Aedes aegypti, Aedes albopictus, Anopheles sinensis, and Culex quinquefasciatus using a portable Agrofog AF35 sprayer indoors in houses on Penang Island, Malaysia. Pesguard FG 161 at the concentrations tested was effective against all 4 mosquito species tested. The water-based Pesguard FG 161 performed far better as a larvicide than the diesel-based formulation. Resigen was also effective as a larvicide and adulticide against all 4 mosquito species tested. Larvae of Ae. aegypti were most susceptible to water-based Pesguard FG 161, followed by Cx. quinquefasciatus, An. sinensis, and Ae. albopictus. Even at the lowest concentrations tested, Pesguard FG 161 showed adequate adulticidal properties. At higher dosages, water-based Pesguard FG 161 proved effective as a larvicide against all 4 mosquito species.

Aedes↗
PubMed2002

Indoor thermal fogging against vector mosquitoes with two Bacillus thuringiensis israelensis formulations, Vectobac ABG 6511 water-dispersible granules and Vectobac 12AS liquid.

Bioefficacy of thermal fogging application of 2 Bacillus thuringiensis israelensis formulations, Vectobac ABG 6511 water-dispersible granules (3,000 international toxic unit [ITU]/mg) and Vectobac 12AS liquid (1,200 ITU/mg), was assessed for larvicidal activities against Aedes aegypti, Aedes albopictus, Anopheles dirus, and Culex quinquefasciatus. Portable Agrofog AF35 sprayers were used to apply the 2 formulations indoors in residential premises on Penang Island, Malaysia. Vectobac ABG 6511 showed good larvicidal effect against all 4 mosquito species at 3 of the higher doses tested (2.91 x 10(9), 1.45 x 10(9), and 0.71 x 10(9) ITU/ha), with more than 96% mortality at 48 h after spraying. As a comparative formulation, Vectobac 12AS also showed good larvicidal activity against all 4 mosquito species at 2 of the higher doses tested (2.87 x 10(9) and 1.46 x 10(9) ITU/ha), with more than 92.5% mortality at 48 h after spraying. Larvae of An. dirus were significantly more susceptible to both water-based Vectobac formulations when compared to the other 3 mosquito species. Both microbial formulations showed better efficacy at higher doses. However, even at the lowest dose tested, Vectobac ABG 6511 and Vectobac 12AS (both at 0.36 x 10(9) ITU/ha) showed larvicidal properties, with more than 66% mortality at 48 h after spraying. Overall, for this bacterial agent, the water-dispersible granule formulation has better prospects than the liquid formulation for the control of larvae of vector mosquitoes.

Aedes↗
PubMed2005

[Up-conversion luminescence and volumetric display research on Er(0.5): FOG material excited by 1 520 nm laser].

The volumetric display technology is one of the important science frontiers of modern society. Multi-photon up-conversion volumetric 3-D display, attractive especially in its self-spatial vision, has the advantages of total-solidification, high reliability and speedy operation so that it has a broad range of applications. The up-conversion luminescence of oxyfluoride glass material Er(0.5): FOG, when excited by 1 520 nm semiconductor laser, was studied. The common-fluorescence spectra were measured also, in order to know up-conversion sufficiently. It was found that there are several up-conversion luminescence lines (407.43, 411.20 nm), (522.51(m), 528.57 nm), (540.53(m), 543.70, 549.00 nm), (654.75(m), 665.50 nm) and 802.10(m) nm, which can be recognized as the fluorescence-transitions of (2G4F2H)9/2 --> 4 I15/2, 4H11/2 --> 4 I15/2, 4S3/2 --> 4 I15/2, 4F9/2 --> 4I15/2 and 4I9/2 --> I15/2 respectively. It is interesting that the slopes of log F-log P curves, the double logarithmic variation of up-conversion luminescence intensity F with the laser power P, are various for these observed up-conversion luminescences, which are valuable for volumetric display. The comprehensive analysis found that the (2G4F2H)9/2 --> 4I15/2 up-conversion luminescence is a four photon up-conversion luminescence, while [2 H11/2 --> 4I15/2, 4S3/2 --> 4I15/2 and 4F9/2 --> 4I15/2] up-conversion luminescence is three-photon up-conversion luminescences, and 4I9/2 --> 4I15/2 up-conversion luminescence is a two-photon up-conversion luminescence. It was found also that the absorption from the ground-state 4I15/2 level to first excited level is very large, resulting in the fact that the sequential energy transfer and step-by-step absorption up-conversion are readily to happen.

Energy Transfer↗
PubMed1990

Evaluation of hand applied naled thermal fog for Wyeomyia control.

Tests on the effect of hand applied naled thermal fog, both as a single treatment on one day/week and a single treatment on 3 successive days, did not control Wyeomyia vanduzeei and Wy. mitchellii. Five-min landing/biting counts in a native oak/palm woodland demonstrated that single applications produced an average landing rate decrease of 13%. Treatments 3 days in succession did not suppress the landing rate.

Animals↗
PubMed1987

Effects of aerial thermal fog applications of fenthion on caged pink shrimp, mysids and sheepshead minnows.

Mosquito control applications of fenthion by aerial thermal fog equipment were studied at 2 sites in Collier County, FL, for sprays that occurred on June 20 and 23, 1984. Acute, lethal effects of fenthion deposited in these estuarine habitats were assessed for caged pink shrimp (Penaeus duorarum), mysids (Mysidopsis bahia) and sheepshead minnows (Cyprinodon variegatus). At Site 1, along a bay with substantial dilution and tidal mixing, fenthion concentrations of 1.5 and 0.29 micrograms/liter were measured in samples taken immediately after both sprays. Concentrations decreased to less than or equal to 0.020 microgram/liter 12 h postspray and no mortality was observed for caged pink shrimp and mysids. Site 2 was along a residential canal system that offered limited dilution and mixing. Maximum concentrations were 2.6 and 0.51 micrograms/liter and measurable concentrations (greater than 0.038 microgram/liter) of fenthion persisted at this site for 4 days. Fenthion concentrations in surface waters were toxic to caged pink shrimp and mysids after both sprays. No mortality occurred among caged sheepshead minnows at either site.

Animals↗
PubMed1984

Multiparametrical approach to fog-challenge-induced bronchial hyperreactivity in asthmatics--protective effects of salbutamol plus beclomethasone dipropionate.

A multiparametrical method was used in order to evaluate the characteristics of fog-challenge-induced bronchoreactivity. The effects of the bronchial stimulation were measured by means of spirometrical tests; determination of ventilatory resistances using a new method by interruption and rapid analysis of the expiratory gases, CO2 and He, according to the "multiple single breath" method. The protective efficacy of salbutamol and the salbutamol plus beclomethasone dipropionate combination was evaluated. The results obtained indicate that the combination exerts a greater protective effect, probably related to the stabilizing action of beclomethasone on the bronchial mucosa.

Aerosols↗
PubMed1983

A mask strip to prevent fogging of glasses at surgery.

A device to prevent the surgeon's eyeglasses and instrument eyepieces from fogging is described. It consists of a double adhesive-faced tape strip that is placed along the upper border of the surgical mask so that it adheres to the mask and to the face, preventing the upward passage of moist air.

Eyeglasses↗
PubMed1981

[Fogging effect in the ischemic cerebral infarction to computerized tomography (author's transl)].

We have examined, with systematic serial computerized tomography (CT) studies, 6 patients with persistent ischemic cerebral infarction. The CT of the ischemic cerebral infarction shows, during the third week, an isodense area. We have called this phenomenon "fogging effect" because at this effect and the CT report could be negative. The possibility of a false negative can be avoided by a control study with contrast medium: the infarction has an intensive contrast enhancement.

Adolescent↗
PubMed1993

Temperature and flow rate effects on mass median diameters of thermally generated malathion and naled fogs.

The effects of temperature and flow rate on mass median diameters (mmds) of thermally generated aerosol clouds were studied. Number 2 fuel oil alone, undiluted and diluted malathion 91, and undiluted naled were examined. There was a significant flow rate x temperature interaction on the mmds of diluted malathion fogs: i.e., differences among flow rates depended on temperature and vice versa.

Aerosols↗
PubMed1993

[The professional status of analytic and adolescent psychotherapists in the "FOGS Study].

Analytic psychotherapists for children and young people are the only group of psychoanalytic methods among "laypersons" has become reality. These therapists are integrated into the overall German health care system. The author discusses the scope of their activities as reflected by the "FOGS Study", underlining the medico-centric profile displayed by this professional group and the attendant duality characteristic of it. On the one hand, these therapists are incorporated organisationally into the professional associations of the psychoanalysts, but in their activities and trainee work they are largely autonomous. It is to be hoped that the planned "Psychotherapist Law" will provide this group with a status in which their legal standing and their specific therapeutic identity will be more closely matched.

Adolescent↗
PubMed1997

On lifting the fog of war in the battle on heart disease: Star Wars technology in pursuit of a seamless integration strategy.

In our efforts to reduce cardiac morbidity and mortality we often use terms such as the "battle" or "war" on heart disease. If we believe efforts to reduce cardiac disease are the moral equivalent of war, then perhaps we should explore ways that military strategic and tactical metaphors can be applied through technology to the cardiac battle. In this article we explore three major areas for technological advancement: adaptation of the strategies of outcomes management and evidence-based medicine, computer simulation and animation efforts to create horizontal and vertical integration of strategic efforts, and use of interactive multimedia in "recruiting an army" through community empowerment. The overall goal is to find ways to lift "the fog of war" in the battle on heart disease, in order to further the integration of our various efforts.

Cardiovascular Diseases↗