Haze in the Klang Valley of Malaysia

Continuous measurements of dry aerosol light scattering (Bsp) were made at two sites in the Klang Valley of Malaysia between December 1998 and December 2000. In addition 24-h PM2.5 samples were collected on a one-day-in-six cycle and the chemical composition of the aerosol was determined. Periods of excessive haze were defined as 24-h average Bsp values greater than 150 Mm-1 and these occurred on a number of occasions, between May and September 1999, during May 2000, and between July and September 2000. The evidence for smoke being a significant contributor to aerosol during periods of excessive haze is discussed and includes features of the aerosol chemistry, the diurnal cycle of Bsp, and the coincidence of forest fires on Sumatra during the southwest (SW) monsoon period, as well as transport modelling for one week of the southwest Monsoon of 2000. The study highlights that whilst transboundary smoke is a major contributor to poor visibility in the Klang Valley, smoke from fires on Peninsular Malaysia is also a contributor, and at all times, the domestic source of secondary particle production is present

A study on elasto-plastic impact friction

A purpose-built pendulum machine was used to study the oblique impact and the behaviour of the surface layers of a normalized low alloy steel subjected to the impact of hard [alpha]-alumina balls. The effect of relative tangential velocity on impulses, restitution coefficient and impact energy loss, was analysed. The morphology of the impact indentations was characterized and related to the impulses obtained. There was lip formation in the target material with ejection of a small fragile oxidized chip, at a certain critical sliding speed. The impact duration and the impulse ratio have maximum values. These values seem to be related to the critical angle of attack, common in abrasive and erosive ductile processes. The experimental results were compared with some impact models and theories.http://www.sciencedirect.com/science/article/B6V5B-3WRC3G0-4/1/41e4c5269f22928dae6bfa3fb640fd0

A General Approach to Optomechanical Parametric Instabilities

We present a simple feedback description of parametric instabilities which can be applied to a variety of optical systems. Parametric instabilities are of particular interest to the field of gravitational-wave interferometry where high mechanical quality factors and a large amount of stored optical power have the potential for instability. In our use of Advanced LIGO as an example application, we find that parametric instabilities, if left unaddressed, present a potential threat to the stability of high-power operation

Data filtering in the readout of the CMS Electromagnetic Calorimeter

For an efficient data taking, the Electromagnetic Calorimeter (ECAL) data of the CMS experiment must be limited to 10\% of the full event size (1MB). Other requirements limit the average data size to 2kB per data acquisition link. These conditions imply a reduction factor of close to twenty on the data collected. The data filtering in the readout of the ECAL detector is discussed. Test beam data are used to study the digital filtering applied in the readout channels and a full detector simulation allows to estimate the energy thresholds to achieve the desired data suppression factor

Action de l'arséniate d'étain sur divers cestodes du mouton

L'arséniate d'étain (AsO4HSn, 1/2 H2O) élimine complètement les infestations des moutons par Moniezia expansa, M. benedeni, Stilesia globipunctata et Avitallina centripunctata. Seul S. hepatica échappe à son action. L'administration doit être faite en supprimant la distribution d'eau 12 heures avant et 4 heures après le traitement. Deux dosages sont utilisés : 250 mg par tête permet l'élimination de M. expansa et M. benedeni alors qu'une dose de 350 mg doit être utilisée en cas d'infestation par les autres Anoplocephalidae. Dans ce cas, l'arrêt de distribution d'eau doit durer de 20 heures avant le traitement à 4 heures après. Ce traitement n'entraîne pas d'avortement et permet une croissance très rapide et un rétablissement des animaux infestés en un temps record. Dans les pays tropicaux, du fait des conditions extérieures défavorables prévalant de mai à novembre, l’arséniate d’étain doit être manipulé avec de grandes précautions, notamment pour les fortes doses (350 et 500 mg). La dose létale se situe autour de 2 à 2,5 g ce qui donne un coefficient chimie-thérapeutique de 8-9 (dose de 250 mg) et de 6 (350 mg). La toxicité pour l’homme des viandes provenant d’animaux traités à 250 mg et à 350 mg est absolument nulle dès le cinquième ou sixième jour après l’administration d’arséniate

Action de l'arséniate d'étain sur quelques cestodes et nématodes du poulet

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Association between congenital toxoplasmosis and preterm birth, low birthweight and small for gestational age birth.

OBJECTIVE: To determine the association between congenital toxoplasmosis and preterm birth, low birthweight and small for gestational age birth. DESIGN: Multicentre prospective cohort study. SETTING: Ten European centres offering prenatal screening for toxoplasmosis. POPULATION: Deliveries after 23 weeks of gestation in 386 women with singleton pregnancies who seroconverted to toxoplasma infection before 20 weeks of gestation. Deliveries after 36 weeks in 234 women who seroconverted at 20 weeks or later, and tested positive before 37 weeks. METHODS: Comparison of infected and uninfected births, adjusted for parity and country of birth. MAIN OUTCOME MEASURES: Differences in gestational age at birth, birthweight and birthweight centile. RESULTS: Infected babies were born or delivered earlier than uninfected babies: the mean difference for seroconverters before 20 weeks was -5.4 days (95% CI: -1.4, -9.4), and at 20 weeks or more, -2.6 days (95% CI: -0.5, -4.7). Congenital infection was associated with an increased risk of preterm delivery when seroconversion occurred before 20 weeks (OR 4.71; 95% CI: 2.03, 10.9). No significant differences were detected for birthweight or birthweight centile. CONCLUSION: Babies with congenital toxoplasmosis were born earlier than uninfected babies but the mechanism leading to shorter length of gestation is unknown. Congenital infection could precipitate early delivery or prompt caesarean section or induction of delivery. We found no evidence for a significant association between congenital toxoplasmosis and reduced birthweight or small for gestational age birth

“Leptin and leptin receptor expression in asthma”

Background: The adipokine leptin is a potential new mediator for bronchial epithelial homeostasis. Asthma is a chronic inflammatory disease characterized by airway remodeling that might affect disease chronicity and severity. TGF-b is a tissue growth factor the dysregulation of which is associated with airway remodeling. Objective: We sought to determine whether a bronchial epithelial dysfunction of the leptin/leptin receptor pathway contributes to asthma pathogenesis and severity. Methods: We investigated in vitro the presence of leptin/leptin receptor on human bronchial epithelial cells. Then we studied the effect of TGF-b and fluticasone propionate on leptin receptor expression. Finally, the role of leptin on TGF-b release and cell proliferation was analyzed. Ex vivo we investigated the presence of leptin/leptin receptor in the epithelium of bronchial biopsy specimens from subjects with asthma of various severities and from healthy volunteers, and some features of airway remodeling, such as reticular basement membrane (RBM) thickness and TGF-b expression in the epithelium, were assessed. Results: In vitro bronchial epithelial cells express leptin/leptin receptor. TGF-b decreased and fluticasone propionate increased leptin receptor expression, and leptin decreased the spontaneous release of TGF-b and increased cell proliferation. Ex vivo the bronchial epithelium of subjects with mild, uncontrolled, untreated asthma showed a decrease expression of leptin and its receptor and an increased RBM thickness and TGF-b expression when compared with values seen in healthy volunteers. Furthermore, severe asthma was associated with a reduced expression of leptin and its receptor and an increased RBM thickness with unaltered TGF-b expression. Conclusions: Decreased expression of leptin/leptin receptor characterizes severe asthma and is associated with airway remodeling features