Semi-urban Site Research Articles

Stable isotopes identify dietary changes associated with beak deformities in Black-capped Chickadees (Poecile atricapillus)

ABSTRACT. A large number of beak deformities of unknown etiology have recently been reported in Black-capped Chickadees (Poecile atricapillus) and other resident avian species in Alaska. We investigated the potential association between diet and beak deformities. We analyzed carbon (δ13C) and nitrogen (δ15N) isotopes in whole blood of Black-capped Chickadees captured at three semiurban sites in south-central Alaska. For dietary analysis, we included natural foods (arthropods, seeds, and berries) and anthropogenic items commonly provided in bird feeders (sunflower seeds, peanut butter, and suet). Blood samples from individuals with beak deformities exhibited lower δ15N values and more variable δ13C values than birds with normal beaks. Isotopic values of blood also differed by location for both carbon and nitrogen, but we did not detect a difference in natural dietary items across the three sites. Contributions of individual diet items differed between birds with and without beak deformities, a pattern that...

A Study on Outbreak of Dengue from Bihar, India-Establishing New Foci, Attributable to Climatic Changes Ragini Mishra1* and Prashant Kumar2

Dengue fever (DF) is a mosquito-borne viral infection which is emerging fast in terms of mortality and morbidity in humans worldwide, particularly in tropical and subtropical countries. DF is characterized clinically by headache, retro-orbital pain, myalgia, arthralgia, integumentary rashes, and sometimes with haemorrhagic manifestations. Aedes aegypti, the main vector species of dengue fever/dengue haemorrhagic fever (DHF) is commonly found in urban areas which can be attributed to the availability of breeding sites such as water storage containers due to poor management of water and limited supply of drinking water, non degradable tyres, long lasting plastic containers and ineffective community participation in eliminating the breeding places. However, new foci are a major concern for public health by affecting the epidemiology of this disease such as rural and semi-urban areas, which may be linked to climate change. Climate change has led to unusual rainfall pattern leading to excess rain in some parts and deficient rainfall in other parts. This is accompanied by overall rise in average temperature which favors fast circulation of the vector and consequently of dengue virus in the environment. Thus, epidemiological, environmental and entomological observations were made to confirm the aetiology of a focal outbreak of dengue fever in rural and semi-urban areas providing breeding sites for larval growth. The present research aimed to record outbreak of dengue from new foci from Bihar, India, and correlates it with climate change. Bihar was said to be free from dengue but in September, 2010, outbreaks have been reported specially from three districts: Patna, Munger and Begusarai. The epidemiological investigation of probable cases showed clustered distribution of cases in adjacent houses and streets and absence of travellers to dengue endemic regions, though many cases of migration was also noted during early phase of outbreak. Cases reported from Patna were mostly related to migration from different areas in order to get better treatment facilities. Entomological investigations were carried out in 60, 94 and 75 houses in the districts of Patna, Munger and Begusarai respectively. The index of House, Container and Breteau from Patna, Munger and Begusarai found were 20, 40 and 29, 11.11, 43 and 31, and 26, 91.48 and 56, respectively, thereby indicating the high receptivity of Munger to DF/DHF transmission which can subsequently be confirmed with the number of cases reported from there. The environmental investigations included in this study were average temperature, humidity and rainfall of three affected districts. The averages temperatures during the outbreak from Patna were 32.21 (maximum) and 25.09 (minimum), from Munger were 32.39 (maximum) and 25.19 (minimum) and from Begusarai were 32.33 (maximum) and 25.43 (minimum). The rate of humidity from Patna were 86.29 (morning) and 82.43 (evening), from Munger were 84.97 (morning) and 82.86 (evening) and from Begusarai were 84.12 (morning) and 83.43 (evening). The rate of rainfall in the year 2010 was 226.9, 220.00 and 224.45 mm for Patna, Munger and Begusarai respectively. The reasons for death may be attributed to absence of herd immunity in new foci. Key words: Rural areas, new foci of dengue, Aedes aegypti, house index, container index, Breteau index, climate change.

Comparison of Annular Diffusion Denuder and High Volume Air Samplers for Measuring Per- and Polyfluoroalkyl Substances in the Atmosphere

Overestimation of the particle phase concentration collected on glass-fiber filters (GFFs) has been reported for perfluoroalkyl carboxylic acids (PFCAs) using conventional high volume air samplers. In this study, per- and polyfluoroalkyl substances (PFASs) were determined in the gas and particulate phases using colocated annular diffusion denuder and high volume air samplers at a semiurban site in Toronto, Canada, in winter 2010. Samples were analyzed for 7 PFAS classes (i.e., PFCAs, perfluoro-alkane sulfonic acids (PFSAs), fluorotelomer alcohols (FTOHs), fluorotelomer methacrylates (FTMACs), fluorotelomer acrylates (FTACs), perfluorooctane sulfonamides (FOSAs), and perfluorooctane sulfonamidoethanols (FOSEs)). The gas diffusion coefficients for individual PFASs were calculated and the denuder performance was evaluated. Modeled subcooled liquid vapor pressures (p(L)) correlated well with the vapor phase breakthrough for the denuder and high volume air systems. Total air concentrations for PFASs measured using annular diffusion denuders and high volume samplers were in agreement within a factor of 4; however, much greater differences were observed for measurements of gas-particle partitioning. Vapor phase PFSAs and PFCAs can adsorb to the GFF using high volume air samplers, resulting in much higher particle-associated fractions for these chemicals compared to the annular diffusion denuder sampler. This effect was not observed for the FTOHs, FTMACs, FTACs, FOSAs, and FOSEs. Thus, for investigations of gas-particle partitioning of PFSAs and PFCAs, the diffusion denuder sampler is the preferred method. The results of this study improve our understanding of the gas-particle partitioning of PFASs, which is important for modeling their long-range transport in air.

Chemical characteristics of aerosols and trace gas distribution over North and Central India

A field campaign on aerosol chemical properties and trace gases measurements was carried out along the Delhi-Hyderabad-Delhi road corridor (spanning about 3,200 km) in India, during February 1-29, 2004. Aerosol particles were collected on quartz and cellulose filters using high volume (PM(10)) sampler at various locations along the route (i.e., urban, semi-urban, rural, and forest areas) and have been characterized for major cations (Na(+), Ca(2+), Mg(2+), K(+), and NH (4) (+)), anions (Cl(-), NO (3)(-), and SO (4)(2-)), and heavy metals (Cu, Cd, Fe, Zn, Mn, and Pb). Simultaneously, we measured NO(2) and SO(2) gases. These species show large spatial and temporal variations. The ambient PM(10) concentration has been observed to be the highest (55 ± 4 μg m(-3)) near semi-urban areas followed by forest areas (48 ± 2 μg m(-3)) and in rural areas (44 ± 22 μg m(-3)). The concentrations of NO( x ) (NO(2)+NO) and SO(2) ranged from 16 to 69 μg m(-3) and 4 to 11 μg m(-3), respectively. Among anions, NO(3)(-) and SO(4) (2-) are the major constituents of PM(10). The urban and semi-urban sites showed enhanced concentrations of Fe, Zn, Mn, Cd, and Pb. This study provide information about atmospheric concentrations of various species in the northern to central India, which may be important for policy makers to better understand the air quality of the region.

On the variation of aerosol properties over Finland based on the optical columnar measurements

Long-range aerosol transport over Finland has been studied using ground-based sunphotometer measurements of aerosol optical properties. Cimel sunphotometers were used at an urban site (Helsinki), a rural site (Hyytiälä) and a semiurban site (Kuopio) and PFR sunphotometer measurements were made at two rural sites, Jokioinen and Sodankylä. The CIMEL measurements are part of the AERONET (Aerosol robotic network) network and Jokioinen and Sodankylä are GAW-PFR (Global Atmosphere Watch-Precision Filter Radiometer) Associate Stations. Sunphotometers provide information on local columnar aerosol properties such as aerosol optical depth (AOD) and Ångström exponent (ÅE) that were used to investigate the aerosol content and aerosol type in this region. A set of representative event days, i.e. days with high turbidity, covering the time period between March 2006 and June 2010 has been selected for further analysis. For these days the AOD results were combined with air mass back trajectories to provide information about the air mass origin, especially for cases with moderate turbidity produced by long-range transported aerosols from mid latitudes to Finland. As expected, episodes with high AOD are connected with the transport of polluted air masses originating from the east or southeast or from industrial areas in Central Europe. We distinguished events with long range transported air pollution from cases where pollution was accumulated in the area due to the local meteorological factors.

Elemental concentration and source identification of PM10 and PM2.5 by SR-XRF in Córdoba City, Argentina

24-h samplings of PM10 and PM2.5 have been carried out during the period July 2009–April 2010 at an urban and at a semi-urban site of Córdoba City (Argentina). The samples in the PM2.5 fraction weighted in the average 71 ± 21 μg m−3 and 67 ± 18 μg m−3 respectively, whereas the samples of the same sites in the PM10 fraction weighted 107 ± 31 μg m−3 and 101 ± 14 μg m−3. The chemical composition of aerosol particles was determined by synchrotron radiation X-ray fluorescence (SR-XRF). Elemental composition was different in the two fractions: in the finer one the presence of elements with crustal origin is reduced, while the anthropogenic elements, with a relevant environmental and health impact, appear to be increased. An important but unmeasured component is likely constituted by organic and elemental carbon compounds. Multivariate analysis (Positive Matrix Factorization) of the SR-XRF data resolved a number of components (factors) which, on the basis of their chemical compositions, were assigned physical meanings.

여과지를 이용한 유기탄소의 측정 오차 보정

This study describes the impact of positive sampling artifact caused by a filter-based sampling in the determination of ambient organic carbon (OC). Three different sampling media combinations were employed for this investigation: (1) Quartz filter-alone (Q-alone), (2) quartz filter behind quartz-fiber filter (QBQ), and (3) quartz filter and quartz filter behind Teflon filter (Q-QBT). The measurement of ambient OC was carried out at a semi-urban site near oceanside at the end of November of 2008. It was found that Q-alone sampling configuration resulted in a higher OC than QBQ and Q-QBT by 14% and 28%, respectively due to no correction for positive artifact caused by adsorption of gas-phase OC onto the filter. A lower quantity of OC was collected from the backup quartz filter on QBQ than that from Q-QBT. A possible explanation is that the front quartz filter of QBQ was not fully saturated with gas-phase OC during the sampling period, allowing smaller amount of gas-phase OC to reach the backup quartz filter. The contribution of positive artifact to <TEX>$PM_{2.5}$</TEX> mass was approximately 2.15 <TEX>${\mu}g/m^3$</TEX> which is equivalent to 6% in terms of Q-QBT sampling configuration. The positive artifact was found to be more dominated during summer than during winter, showing temperature dependence. It was concluded that Q-QBT sampling configuration offers less impact of positive artifact on ambient OC sampling than QBQ in quantification of OC.

What Knowledge and Expectations are Ethiopian Girls Bringing with Them into Parenthood?

Background Because of rapid population growth, many countries now have very large cohorts of young people. Despite the population health importance of early child feeding practices, little work has explored the knowledge and expectations about infant feeding that youth bring with them as they transition into parenthood. Objective To examine adolescent girls' perceptions of infant and young child feeding practices in their communities, and to assess their knowledge and expectations regarding infant and young child feeding practices and explore their overlap with current feeding recommendations. Methods Cross-sectional data were obtained from a random sample of 1,018 girls 13 to 17 years of age living in rural, semiurban, and urban sites in southwestern Ethiopia. Surveys were used to collect information on respondents' attitudes, expectations, and perceptions within the domain of infant and young child feeding practices. Descriptive and bivariate statistics were used to describe the data. Results A total of 1,018 girls aged 13 to 17 years were interviewed. The girls were able to report the age at which infants in their communities were provided liquids, semisolids, and solids as well as the perceived duration of breastfeeding in their communities. The girls were generally able to report when they themselves planned to provide liquids and solids to their infants and their expected duration of breastfeeding. The girls' attitudes and expectations were not consistent with exclusive breastfeeding to 6 months, and planned durations of breastfeeding were shorter than they currently perceived in their communities. Conclusions Young nulliparous Ethiopian women have well-formed attitudes and expectations about infant and young child feeding. These are unlikely to promote currently accepted best practices. Our results suggest both the potential that suboptimal feeding practices will be reproduced and novel intervention points.

Chemical characteristics and sources of organic acids in precipitation at a semi-urban site in Southwest China

In order to investigate the chemical characteristics and sources of organic acids in precipitation in Southwest China, 105 rainwater samples were collected at a semi-urban site in Anshun from June 2007 to June 2008. Organic acids and major anions were analyzed along with pH and electrical conductivity. The pH values varied from 3.57 to 7.09 for all the rainfall events sampled, with an average of 4.67 which was typical acidic value. Formic, acetic and oxalic acids were found to be the predominant carboxylic acids and their volume weighted average (VWA) concentrations were 8.77, 6.93 and 2.84 μmol l−1, respectively. These organic acids were estimated to account for 8.1% to the total free acidity (TFA) in precipitation. The concentrations of the majority organic acids at studied site had a clear seasonal pattern, reaching higher levels during the non-growing season than those in growing season, which was attributed to dilution effect of heavy rainfall during the growing season. The seasonal variation of wet deposition flux of these organic acids confirmed higher source strength of biogenic emissions from vegetation during the growing season. Formic-to-acetic acids ratio (F/A), an indicator of primary versus secondary sources of these organic acids, suggested that primary sources from vehicular emission, biomass burning, soil and vegetation emissions were dominant sources. In addition, the lowest concentrations of organic acids were found under type S, when air masses originated from the marine (South China Sea) during Southern Asian Monsoon period. And the highest concentrations were observed in precipitation events from Northeast China (type NE), prevailing mostly during winter with the lowest rainfall.

Polybromodiphenyl ethers in mothers and their newborns from a non-occupationally exposed population (Valencia, Spain)

Polybromodiphenyl ethers (PBDEs) were analyzed in blood serum of pregnant women and in cord blood serum of their newborns from a general population cohort (n = 174; Valencia, Spain). The most abundant PBDE congeners identified were BDE 47, BDE 99, BDE 153, BDE 154 and BDE 209. Their cord blood serum concentrations were about 45% of those in maternal serum but after lipid normalization about the same concentrations were observed in both types of samples. Thus, median of total PBDEs was 9.6 ng/g lipid in cord serum (range between not detected and 140 ng/g lipid) and 9.6 ng/g lipid in maternal serum (range between not detected and 120 ng/g lipid). The distributions of these compounds were dominated by BDE 47 in both cases. In cord blood serum the decreasing order of abundance was BDE 47 > BDE 99 > BDE 209 > BDE 153 > BDE 154. The congener composition in maternal serum followed a similar trend: BDE 47 > BDE 153 > BDE 154 > BDE 209 > BDE 99. The congener concentrations exhibited a higher degree of correlation in cord blood than in maternal serum. Use of the maternal determinants for categorization of the observed maternal and fetal PBDE concentrations only showed significant associations for the levels in umbilical cord. Neonates from rural areas exhibited statistically significantly lower concentrations than those from urban, semi-urban or metropolitan sites. Maternal serum also showed this difference but the higher dispersion of the concentrations in maternal serum did not afford its recognition with statistical significance. The lower qualitative and quantitative variability in the PBDE concentrations of cord blood serum than maternal serum suggest that the latter is reflecting PBDE contributions from a wider diversity of sources than the former whereas cord blood sera seem to represent the long term standing stock of these compounds accumulated in the maternal tissues.

Source characterization for aerosol constituents and changing roles of calcium and ammonium aerosols in the neutralization of aerosol acidity at a semi-urban site in SW India

Atmospheric aerosols were collected at a semi-urban site in Pune city, located in the southwestern part of India, during the year 2007–08 covering different seasons. Anthropogenically derived particles (Non seasalt and non crustal fractions of SO4, Cl, K, Ca and Mg together with NO3, NH4, Cu, Zn and black carbon) contributed about 73% of the total measured TSP. Natural sources like sea (16%) and soil (11%) contributed about 27% to the total measured composition of TSP on annual basis. Surprisingly, Ca which is generally observed from crustal source, showed equal contribution from crustal and anthropogenic sources and was the major neutralizer of aerosol acidity in summer and monsoon seasons. NH4 was the most abundant component on annual average basis among the measured chemical components and also it was the leading neutralizer of aerosol acidity during post-monsoon and winter seasons. Aerosols showed alkaline nature (mean annual pH 6.51 and Neutralization Potential/Acidic Potential ratio 1.45) due to the neutralizing effect of Ca and NH4.

Fluorescent biological aerosol particle concentrations and size distributions measured with an Ultraviolet Aerodynamic Particle Sizer (UV-APS) in Central Europe

Abstract. Primary Biological Aerosol Particles (PBAPs), including bacteria, spores and pollen, are essential for the spread of organisms and disease in the biosphere, and numerous studies have suggested that they may be important for atmospheric processes, including the formation of clouds and precipitation. The atmospheric abundance and size distribution of PBAPs, however, are largely unknown. At a semi-urban site in Mainz, Germany we used an Ultraviolet Aerodynamic Particle Sizer (UV-APS) to measure Fluorescent Biological Aerosol Particles (FBAPs), which provide an estimate of viable bioaerosol particles and can be regarded as an approximate lower limit for the actual abundance of PBAPs. Fluorescence of non-biological aerosol components are likely to influence the measurement results obtained for fine particles (&lt;1 μm), but not for coarse particles (1–20 μm). Averaged over the four-month measurement period (August–December 2006), the mean number concentration of coarse FBAPs was ~3×10−2 cm−3, corresponding to ~4% of total coarse particle number. The mean mass concentration of FBAPs was ~1μg m−3, corresponding to ~20% of total coarse particle mass. The FBAP number size distributions exhibited alternating patterns with peaks at various diameters. A pronounced peak at ~3 μm was essentially always observed and can be described by the following campaign-average lognormal fit parameters: geometric mean diameter 3.2 μm, geometric standard deviation 1.3, number concentration 1.6×10−2 cm−3. This peak is likely due to fungal spores or agglomerated bacteria, and it exhibited a pronounced diel cycle (24-h) with maximum intensity during early/mid-morning. FBAP peaks around ~1.5 μm, ~5 μm, and ~13 μm were also observed, but less pronounced and less frequent. These may be single bacterial cells, larger fungal spores, and pollen grains, respectively. The observed number concentrations and characteristic sizes of FBAPs are consistent with microscopic, biological and chemical analyses of PBAPs in aerosol filter samples. To our knowledge, however, this is the first exploratory study reporting continuous online measurements of bioaerosol particles over several months and a range of characteristic size distribution patterns with a persistent bioaerosol peak at ~3 μm. The measurement results confirm that PBAPs account for a substantial proportion of coarse aerosol particle number and mass in continental boundary layer air. Moreover, they suggest that the number concentration of viable bioparticles is dominated by fungal spores or agglomerated bacteria with aerodynamic diameters around 3 μm rather than single bacterial cells with diameters around 1 μm.

Prevalence of HIV/AIDS: A report based on a survey in women attending ANC services in Eritrea in 2005

Study objective: To determine the prevalence and socio-demographic factors of HIV in ANC attendees in Eritrea. Methods: Cross sectional anonymous unlinked sentinel surveillance of HIV prevalence in ANC attendee pregnant women frpm March 2005 to May 2006. The study was conducted in 15 clusters; 10 urban and 5 rural clusters with a total of 19 urban and 26 rural sentinel sites that includes all six capital cities and a number of semi urban and rural sentinel sites from all six zones of Eritrea. Cluster sampling, non probability consecutive sampling of pregnant women who came to attend their first ANC in the study sites. Result: The total sample size was 5033. The over all HIV prevalence in pregnant women attending ANC was 2.38%. The highest prevalence was observed in Southern Red Sea zone (5.9%) followed by central zone (3.48%). Lowest prevalence was seen in Anseba zone (1.3%), South zone (1.65%), Northern Red Sea zone (1.77%), and Gash Barka zone (2.06%). It was found to be 3.04% in urban women and 0.9% in rural women. It was also higher in single women 7.2% than in married women 2%. HIV prevalence increased with age (1.3%) in women aged 15-19, 2% in 20-24, 3.8% in 25-29, 2.5% in 30-34, 1.5% in 35-39, 2.7% in 40-44 and 1.8% in 15-24 years age group women. Further the prevalence fluctuated with level of formal education and occupation; 0.9% in illiterate and 4% in women with secondary school education, 1.94% in house wives, 5.9% in women daily labourers, 5.6% in unemployed unmarried women, and 8.5% in commercial sexual workers. 5.4% in women whose partners are truck/bus drivers, 3.8%% in women whose partners are merchants and 2.6% in women whose partner’s are in the military/national service. Conclusion: HIV prevalence in Eritrea is low and declining from the highest 4.2% in 1999 to 2.38% in 2005 ANS sentinel surveillance. HIV prevalence was more prevalent in urban areas, in single, young women and increased with increasing age and educational level and was influenced by the women’s and partners occupation.

Natural ventilation effects on temperatures within Stevenson screens

AbstractThermometer screen properties are poorly characterised at low wind speeds. Temperatures from a large thermometer screen have been compared with those from an automatically shaded open‐air fine‐wire resistance thermometer. For the majority of 5‐minute average measurements obtained between July 2008 and 2009, the screen and fine‐wire temperatures agreed closely, with a median difference &lt;0.05 °C. At low wind speeds however, larger temperature differences occurred. When calm (wind speed at 2 metres, u2, ≤ 0.1 m s−1), the difference between screen and open‐air temperatures varied from −0.25 °C to +0.87 °C. At night with u2 &lt; 0.5 m s−1, this difference was −0.14 °C to 0.39 °C, and, rarely, up to −0.68 °C to 1.38 °C. At the minimum in the daily temperature cycle, the semi‐urban site at Reading had u2 &lt; 1 m s−1 for 52% of the observations 1997–2008, u2 &lt; 0.5 m s−1 for 34% and calm conditions for 20%. Consequently uncertainties in the minimum temperature measurements may arise from poor ventilation, which can propagate through calculations to daily average temperatures. In comparison with the daily minimum temperature, the 0900 UTC synoptic temperature measurement has a much lower abundance (5%) of calm conditions. Copyright © 2010 Royal Meteorological Society

Characterization of atmospheric aerosols for organic tarry matter and combustible matter during crop residue burning and non-crop residue burning months in Northwestern region of India

Aerosol (total suspended particulate) samples collected at three diverse locations (urban-commercial, semi-urban and rural-agricultural) in Patiala, India were analyzed for loss on ignition (LOI) and organic tarry matter (OTM) content in ambient air during crop residue burning (CRB) episodes and non-crop residue burning (NCRB) months in 2006–2007. Results showed high levels of LOI and OTM during wheat and rice crop residue-burning periods at all the sites. Higher levels were obtained during rice crop residue-burning period as compared to the wheat residue-burning period. At semi-urban site, LOI varied between 53 ± 36 μg m −3 and 257 ± 14 μg m −3 constituting 38–78% (w/w) part of the aerosols whereas levels of OTM varied between 0.98 ± 0.11 μg m −3 and 7.93 ± 2.76 μg m −3 comprising 0.42–3.28% (w/w) fraction. At rural-agricultural area site, levels of LOI varied between 86 ± 40 μg m −3 and 293 ± 70 μg m −3 comprising 27–84% (w/w), whereas OTM levels varied between 1.31 ± 0.64 μg m −3 and 10.09 ± 6.56 μg m −3 constituting 0.83–2.42% (w/w) fraction of the aerosols. At urban-cum-commercial site, levels of LOI and OTM varied between 48 ± 23 μg m −3 and 281 ± 152 μg m −3 and 2.53 ± 1.23 μg m −3 and 17.40 ± 8.50 μg m −3, constituting 24–62% (w/w) part of the aerosols, respectively. Results also indicated that OTM and LOI were integral parts of aerosols and their concentrations were influenced by the crop residue burning practices with incorporated effect of vehicular activities in Patiala.

The Impact of Landscape Disturbance on Spatial Genetic Structure in the Guanacaste Tree, Enterolobium cyclocarpum (Fabaceae)

We examined spatial genetic structure (SGS) in Enterolobium cyclocarpum (the Guanacaste tree), a dominant tree of Central American dry forests in 4 sites in Guanacaste Province, Costa Rica. In disturbed dry forest sites (e.g., pastures), E. cyclocarpum is primarily dispersed by cattle and horses, whose movements are restricted by pasture boundaries. The study sites varied in tree densities and disturbance. Allozyme analyses of adult trees demonstrated significant levels of SGS in 3 of 4 sites. SGS was primarily due to clusters of young adults located along seasonal streams, rocky areas, and in abandoned pastures. SGS was highest in the first distance class in the least disturbed population, which also had the lowest density of large adults. Low, but significant SGS characterized the site with the highest number of large adults located in individual pastures. The semiurban site, had no clusters of young adults and, probably as a result, failed to exhibit SGS. Our results demonstrate that disturbance can strongly influence SGS patterns and are consistent with a landscape model in which the location of potential recruitment sites, restricted seed disperser movements, and the number and location of maternal individuals dictate the level and pattern of SGS.

Densidad de sitios para anidar y su uso por dos especies de pájaro carpintero (Melanerpes rubricapillus y M. chrysauchen) (Piciformes: Picidae) en un gradiente urbano de Costa Rica

Density of nesting sites and their use by two woodpecker species (Melanerpes rubricapillus y M. chrysauchen) (Piciformes: Picidae) along an urban gradient, Costa Rica. i examined the density of nest- ing substrates potentially used by two woodpeckers (Melanerpes rubricapillus and M. chrysauchen) along an urban gradient, and their nest density in three sites with different human intervention in Golfito, Costa Rica. The urban and semi-urban sites had the lowest abundance of natural substrates for nesting, as expected by the effect of urban development. Nest abundance was greater in the semiurban site than in other sites, possibly in relation with a greater abundance of woodpeckers. Nests had a grouping distribution, which might reflect the preference of woodpeckers for nesting in natural substrates. The reduction of artificial and natural substrates in urban areas could decrease density population of these two woodpecker species. Rev. Biol. Trop. 57 (Suppl. 1): 351-355 Epub 2009 November 30.

Emission characteristic of ozone related trace gases at a semi-urban site in the Indo-Gangetic plain using inter-correlations

Measurements of surface O3, CO, NOx and light NMHCs were made during December 2004 at Hissar, a semi-urban site in the state of Haryana in north-west region of the Indo-Gangetic Plain (IGP). The night-time O3 values were higher when levels of CO, NO and NO2 were lower but almost zero values were observed during the episodes of elevated mixing ratios of CO (above 2000 ppbv) and NOx (above 50 ppbv). Slopes derived from linear fits of O3 versus CO and O3 versus NOx scatter plots were also negative. However, elevated levels of O3 were observed when CO and NOx were in the range of 200–300 ppbv and 20–30 ppbv, respectively. Slope of CO-NOx of about 33 ppbv/ppbv is much larger than that observed in the US and Europe indicating significant impact of incomplete combustion processes emitting higher CO and lesser NOx. Correlations and ratios of these trace gases including NMHCs show dominance of recently emitted pollutants mostly from biomass burning at this site.

Simultaneous measurements of ozone and its precursors on a diurnal scale at a semi urban site in India

Simultaneous observations of surface ozone (O3) with its precursors namely, carbon monoxide (CO) and oxides of nitrogen (NOx) have been taken on diurnal scale from a tropical semi-urban site, Pune (18.54°N, 73.81°E) in India. We present the data for one year (2003–2004) period to study the salient features of these trace gases. The peak in amplitude of ozone is found during the noontime whereas in CO and NOX it is observed in the morning hours between 0800 and 0900 H. The concentration of these pollutants drop down considerably during southwest monsoon months and the diurnal pattern also become very weak. The diurnal trends of these gases are found to be different for different seasons, which are specific to the receptor site. Model simulations using 3-D chemical-transport model with regional emission inventories and observed winds have also been carried out. The comparison of model results with observations, on seasonal basis yielded a reasonable qualitative agreement. The relative role of local emissions and long range transport in the diurnal pattern for different seasons has been outlined, which reveals that the ozone is highly influenced by regional/long range transport in this region. The effect of precursor amounts in the morning on afternoon ozone peak levels has been investigated using the lag correlation study, which reveals that a time lag of 5–7 h is required for most of these precursor gases to photo-chemically produce ozone to its maximum potential. Results are discussed in the light of available topographic and meteorological conditions.

Daily, weekly, and seasonal time courses of VOC concentrations in a semi-urban area near Barcelona

In order to study the daily, weekly, and seasonal patterns and possible origins of air concentrations of volatile organic compounds (VOCs), measurements were taken on a minute-by-minute basis with a PTR-MS in the vicinity of a highway in a semi-urban site near Barcelona. Four periods of the year were chosen and samples were taken under different meteorological conditions and at different phenological stages of the surrounding vegetation. None of the measured VOCs concentrations exceeded air-quality guidelines. The results showed that diurnal, weekly, and seasonal fluctuations in measured VOC concentrations depended on variations in the strength of sources, as well as on photochemical activity and meteorological conditions. There was a decrease in concentrations in most VOCs when mixing depth, photochemical destruction, and wind speed increased at midday. On the other hand, high values of some VOCs occurred at night when the strength of their sinks and the mixing layer decreased. Interestingly, in June, night emissions and concentration peaks of methanol and acetone occurred in periods with dew formation and no wind. VOCs related to anthropogenic emissions presented a weekly pattern of variation with a clear distinction being found between working days and the weekend. The seasonal variation showed higher levels in December for all VOCs, except for isoprene. The thinning of the mixing layer leading to greater concentrations of volatiles and lower wind speeds in winter could account for those higher VOC levels. Benzene and toluene originated mainly from anthropogenic emissions. The sources of acetaldehyde, methanol, and acetone appeared to be mainly biogenic and these compounds were the most abundant of all the measured VOCs. Isoprene concentration patterns suggest a predominantly anthropogenic origin in December and March and a mainly biogenic origin in June and October. All these data provide useful information on the dynamics of VOCs in an area where ozone levels in summer exceed quite often the standard protection thresholds for O 3.