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Sample records for source seasonal variation

  1. Seasonal and Spatial Variations of Heavy Metals in Two Typical Chinese Rivers: Concentrations, Environmental Risks, and Possible Sources

    Science.gov (United States)

    Yao, Hong; Qian, Xin; Gao, Hailong; Wang, Yulei; Xia, Bisheng

    2014-01-01

    Ten metals were analyzed in samples collected in three seasons (the dry season, the early rainy season, and the late rainy season) from two rivers in China. No observed toxic effect concentrations were used to estimate the risks. The possible sources of the metals in each season, and the dominant source(s) at each site, were assessed using principal components analysis. The metal concentrations in the area studied were found, using t-tests, to vary both seasonally and spatially (P = 0.05). The potential risks in different seasons decreased in the order: early rainy season > dry season > late rainy season, and Cd was the dominant contributor to the total risks associated with heavy metal pollution in the two rivers. The high population and industrial site densities in the Taihu basin have had negative influences on the two rivers. The river that is used as a source of drinking water (the Taipu River) had a low average level of risks caused by the metals. Metals accumulated in environmental media were the main possible sources in the dry season, and emissions from mechanical manufacturing enterprises were the main possible sources in the rainy season. The river in the industrial area (the Wusong River) had a moderate level of risk caused by the metals, and the main sources were industrial emissions. The seasonal and spatial distributions of the heavy metals mean that risk prevention and mitigation measures should be targeted taking these variations into account. PMID:25407421

  2. Seasonal and Spatial Variations of Heavy Metals in Two Typical Chinese Rivers: Concentrations, Environmental Risks, and Possible Sources

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    Hong Yao

    2014-11-01

    Full Text Available Ten metals were analyzed in samples collected in three seasons (the dry season, the early rainy season, and the late rainy season from two rivers in China. No observed toxic effect concentrations were used to estimate the risks. The possible sources of the metals in each season, and the dominant source(s at each site, were assessed using principal components analysis. The metal concentrations in the area studied were found, using t-tests, to vary both seasonally and spatially (P = 0.05. The potential risks in different seasons decreased in the order: early rainy season > dry season > late rainy season, and Cd was the dominant contributor to the total risks associated with heavy metal pollution in the two rivers. The high population and industrial site densities in the Taihu basin have had negative influences on the two rivers. The river that is used as a source of drinking water (the Taipu River had a low average level of risks caused by the metals. Metals accumulated in environmental media were the main possible sources in the dry season, and emissions from mechanical manufacturing enterprises were the main possible sources in the rainy season. The river in the industrial area (the Wusong River had a moderate level of risk caused by the metals, and the main sources were industrial emissions. The seasonal and spatial distributions of the heavy metals mean that risk prevention and mitigation measures should be targeted taking these variations into account.

  3. Seasonal variations and sources of sedimentary organic carbon in Tokyo Bay

    International Nuclear Information System (INIS)

    Kubo, Atsushi; Kanda, Jota

    2017-01-01

    Total organic carbon (TOC), total nitrogen (TN) contents, their stable C and N isotope ratio (δ 13 C and δ 15 N), and chlorophyll a ([Chl a] sed ) of surface sediments were investigated monthly to identify the seasonal variations and sources of organic matter in Tokyo Bay. The sedimentary TOC (TOC sed ) and TN (TN sed ) contents, and the sedimentary δ 13 C and δ 15 N (δ 13 C sed and δ 15 N sed ) values were higher in summer than other seasons. The seasonal variations were controlled by high primary production in the water column and hypoxic water in the bottom water during summer. The fraction of terrestrial and marine derived organic matter was estimated by Bayesian mixing model using stable isotope data and TOC/TN ratio. Surface sediments in Tokyo Bay are dominated by marine derived organic matter, which accounts for about 69 ± 5% of TOC sed . - Highlights: • High values of sedimentary organic carbon and nitrogen were observed in summer. • Surface sediments in Tokyo Bay were dominated by marine derived organic matter which was estimated by Bayesian mixing model. • The most amount of terrestrial POC was deposited and degraded in Tokyo Bay before being discharged to the open ocean.

  4. Seasonal variation and sources of atmospheric gravity waves in the Antarctic

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    Kaoru Sato

    2010-12-01

    Full Text Available In the last recent ten years, our knowledge of gravity waves in the Antarctic has been significantly improved through numerous studies using balloon and satellite observations and high-resolution model simulations. In this report, we introduce results from two studies which were performed as a part of the NIPR project "Integrated analysis of the material circulation in the Antarctic atmosphere-cryosphere-ocean" (2004-2009, i.e., Yoshiki et al. (2004 and Sato and Yoshiki (2008. These two studies focused on the seasonal variation and sources of the gravity waves in the Antarctic, because horizontal wavelengths and phase velocities depend largely on the wave sources. The former study used original high-resolution data from operational radiosonde observations at Syowa Station. In the lowermost stratosphere, gravity waves do not exhibit characteristic seasonal variation; instead, the wave energy is intensified when lower latitude air intrudes into the area near Syowa Station in the upper troposphere. This intrusion is associated with blocking events or developed synoptic-scale waves. In the lower and middle stratosphere, the gravity wave energy is maximized in spring and particularly intensified when the axis of the polar night jet approaches Syowa Station. The latter study is based on intensive radiosonde observation campaigns that were performed in 2002 at Syowa Station as an activity of JARE-43. Gravity wave propagation was statistically examined using two dimensional (i.e., vertical wavenumber versus frequency spectra in each season. It was shown that the gravity waves are radiated upward and downward from an unbalanced region of the polar night jet. This feature is consistent with the gravity-wave resolving GCM simulation.

  5. Seasonal Variations and Sources of Airborne Polycyclic Aromatic Hydrocarbons (PAHs in Chengdu, China

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    Ju Yang

    2018-02-01

    Full Text Available The concentrations of polycyclic aromatic hydrocarbons (PAHs in the air of Chengdu, a southwest city of China, were determined from March 2015 to February 2016. Here, two diagnostic ratios (DR were determined and a principal component analysis/multiple linear regression (PCA/MLR analysis was performed to identify the sources of PAHs during the four seasons. The gaseous and particle phase samples were analyzed separately. The sampled air had a gas-to particle ratio of 4.21, and between 18.7% and 31.3% of the total detected PAHs were found in the particulate phase. The total concentration of all 16-PAHs combined (gas + particles varied from 176.94 in summer to 458.95 ng·m−3 in winter, with a mean of 300.35 ± 176.6 ng·m−3. In the gas phase, phenanthrene(Phe was found at the highest concentrations in all four seasons, while benzo[b]fluoranthene(BbF and (in winter chrysene(Chr were the highest in the particle phase. The DR of Fluroanthene (Flua/(Flua + Pyrene (Pyr was higher in the gas phase than in the particle phase, while the Indeno[1,2,3-cd]pyrene(IcdP/(IcdP + Benzo[ghi]perylene (BghiP ratio was more variable in the gas than that in the particle phase. The main sources for both phases were a mixture of liquid fossil fuel combustion and the burning of biomass and coal, with clear seasonal variation. Principal Component Analysis/Multiple Linear Regression (PCA/MLR analysis identified the main PAH sources as coal burning (52% with motor vehicle exhaust and coke (48% in spring; coal (52%, coke (21%, and motor vehicle exhaust (27% in summer; coal (47%, vehicle exhaust (34%, and coke (19% in autumn; and coal (58% and vehicle exhaust (42% in winter.

  6. Sources of light-absorbing aerosol in arctic snow and their seasonal variation

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    Dean A. Hegg

    2010-11-01

    Full Text Available Two data sets consisting of measurements of light absorbing aerosols (LAA in arctic snow together with suites of other corresponding chemical constituents are presented; the first from Siberia, Greenland and near the North Pole obtained in 2008, and the second from the Canadian arctic obtained in 2009. A preliminary differentiation of the LAA into black carbon (BC and non-BC LAA is done. Source attribution of the light absorbing aerosols was done using a positive matrix factorization (PMF model. Four sources were found for each data set (crop and grass burning, boreal biomass burning, pollution and marine. For both data sets, the crops and grass biomass burning was the main source of both LAA species, suggesting the non-BC LAA was brown carbon. Depth profiles at most of the sites allowed assessment of the seasonal variation in the source strengths. The biomass burning sources dominated in the spring but pollution played a more significant (though rarely dominant role in the fall, winter and, for Greenland, summer. The PMF analysis is consistent with trajectory analysis and satellite fire maps.

  7. Seasonal Variation in Epidemiology

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    Marrero, Osvaldo

    2013-01-01

    Seasonality analyses are important in medical research. If the incidence of a disease shows a seasonal pattern, then an environmental factor must be considered in its etiology. We discuss a method for the simultaneous analysis of seasonal variation in multiple groups. The nuts and bolts are explained using simple trigonometry, an elementary…

  8. Water soluble ions in aerosols (TSP) : Characteristics, sources and seasonal variation over the central Himalayas, Nepal

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    Tripathee, Lekhendra; Kang, Shichang; Zhang, Qianggong; Rupakheti, Dipesh

    2016-04-01

    Atmspheric pollutants transported from South Asia could have adverse impact on the Himalayan ecosystems. Investigation of aerosol chemistry in the Himalayan region in Nepal has been limited on a temporal and spatial scale to date. Therefore, the water-soluble ionic composition of aerosol using TSP sampler was investigated for a year period from April 2013 to March 2014 at four sites Bode, Dhunche, Lumbini and Jomsom characterized as an urban, rural, semi-urban and remote sites in Nepal. During the study period, the highest concentration of major cation was Ca2+ with an average concentration of 8.91, 2.17, 7.85 and 6.42 μg m-3 and the highest concentration of major anion was SO42- with an average of 10.96, 4.06, 6.85 and 3.30 μg m-3 at Bode, Dhunche, Lumbini and Jomsom respectively. The soluble ions showed the decrease in concentrations from urban to the rural site. Correlations and PCA analysis suggested that that SO42-, NO3- and NH4+ were derived from the anthropogenic sources where as the Ca2+ and Mg2+ were from crustal sources. Our results also suggest that the largest acid neutralizing agent at our sampling sites in the central Himalayas are Ca2+ followed by NH4+. Seasonal variations of soluble ions in aerosols showed higher concentrations during pre-monsoon and winter (dry-periods) due to limited precipitation amount and lower concentrations during the monsoon which can be explained by the dilution effect, higher the precipitation lower the concentration. K+ which is regarded as the tracer of biomss burning had a significant peaks during pre-monsoon season when the forest fires are active around the regions. In general, the results of this study suggests that the atmospheric chemistry is influenced by natural and anthropogenic sources. Thus, soluble ionic concentrations in aerosols from central Himalayas, Nepal can provide a useful database to assess atmospheric environment and its impacts on human health and ecosystem in the southern side of central

  9. Seasonal Variation in Drinking and Domestic Water Sources and Quality in Port Harcourt, Nigeria

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    Kumpel, Emily; Cock-Esteb, Alicea; Duret, Michel; de Waal, Dominick; Khush, Ranjiv

    2017-01-01

    We compared dry and rainy season water sources and their quality in the urban region of Port Harcourt, Nigeria. Representative sampling indicated that municipal water supplies represent < 1% of the water sources. Residents rely on privately constructed and maintained boreholes that are supplemented by commercially packaged bottled and sachet drinking water. Contamination by thermotolerant coliforms increased from 21% of drinking water sources in the dry season to 42% of drinking water sources in the rainy season (N = 356 and N = 397). The most significant increase was in sachet water, which showed the lowest frequencies of contamination in the dry season compared with other sources (15%, N = 186) but the highest frequencies during the rainy season (59%, N = 76). Only half as many respondents reported drinking sachet water in the rainy season as in the dry season. Respondents primarily used flush or pour-flush toilets connected to septic tanks (85%, N = 399). The remainder relied on pit latrines and hanging (pier) latrines that drained into surface waters. We found significant associations between fecal contamination in boreholes and the nearby presence of hanging latrines. Sanitary surveys of boreholes showed that more than half were well-constructed, and we did not identify associations between structural or site deficiencies and microbial water quality. The deterioration of drinking water quality during the rainy season is a serious public health risk for both untreated groundwater and commercially packaged water, highlighting a need to address gaps in monitoring and quality control. PMID:27821689

  10. Seasonal variation, sources and gas/particle partitioning of polycyclic aromatic hydrocarbons in Guangzhou, China

    International Nuclear Information System (INIS)

    Yang, Yunyun; Guo, Pengran; Zhang, Qian; Li, Deliang; Zhao, Lan; Mu, Dehai

    2010-01-01

    Air samples were collected weekly at an urban site and a suburban site in Guangzhou City, China, from April 2005 to March 2006, to measure the concentrations of polycyclic aromatic hydrocarbons (PAHs) in the ambient air and study their seasonal variations, gas/particle partitioning, origins and sources. The concentrations of Σ 16-PAHs (particle + gas) were 129.9 ± 73.1 ng m -3 at the urban site and 120.4 ± 48.5 ng m -3 at the suburban site, respectively. It was found that there was no significant difference in PAH concentrations between the urban and suburban sites. Seasonal variations of PAH concentrations at the two sampling sites were similar, with higher levels in the winter that gradually decreased to the lowest levels in the summer. The average concentrations of Σ 16-PAHs in the winter samples were approximately three times higher than those of the summer samples because in the summer local emissions dominated, and in the winter the contribution from outside sources or transported PAHs is increased. The plot of logK p versus logP L 0 for the data sets of summer and winter season samples had significantly different slopes at both sampling sites. The slopes for the winter samples were steeper than those for the summer samples. It was also observed that gas/particle partitioning of PAHs showed different characteristics depending on air parcel trajectories. Steeper slopes were obtained for an air parcel that traveled across the continent to the sampling site from the northern or northeastern sector, whereas shallower slopes were obtained for air masses that traveled across the sea from the southern or eastern sector. Diagnostic ratio analytical results imply that the origins of PAHs were mainly from petroleum combustion and coal/biomass burning. The anthracene/phenanthrene and benzo[a]anthracene/chrysene ratios in the winter were significantly lower than those in the summer, which indicate that there might be long-range transported PAH input to Guangzhou in

  11. Seasonal variation and source estimation of organic compounds in urban aerosol of Augsburg, Germany

    International Nuclear Information System (INIS)

    Pietrogrande, Maria Chiara; Abbaszade, Guelcin; Schnelle-Kreis, Juergen; Bacco, Dimitri; Mercuriali, Mattia; Zimmermann, Ralf

    2011-01-01

    This study reports a general assessment of the organic composition of the PM 2.5 samples collected in the city of Augsburg, Germany in a summer (August-September 2007) and a winter (February-March 2008) campaign of 36 and 30 days, respectively. The samples were directly submitted to in-situ derivatisation thermal desorption gas chromatography coupled with time of flight mass spectrometry (IDTD-GC-TOFMS) to simultaneously determine the concentrations of many classes of molecular markers, such as n-alkanes, iso- and anteiso-alkanes, polycyclic aromatic hydrocarbons (PAHs), oxidized PAHs, n-alkanoic acids, alcohols, saccharides and others. The PCA analysis of the data identified the contributions of three emission sources, i.e., combustion sources, including fossil fuel emissions and biomass burning, vegetative detritus, and oxidized PAHs. The PM chemical composition shows seasonal trend: winter is characterized by high contribution of petroleum/wood combustion while the vegetative component and atmospheric photochemical reactions are predominant in the hot season. - Highlights: → 59 molecular markers were simultaneously determined by thermal desorption GC-MS. → Organic composition of urban PM 2.5 in Augsburg, Germany, was characterized. → Fossil fuel, vegetative detritus, coal/wood burning are the main sources. → Seasonal trends winter vs. summer were identified. - Organic composition of the urban PM 2.5 identifies seasonal trend of the main sources: fossil fuel and biomass combustion sources, vegetative detritus, atmospheric photochemical reactions.

  12. Polycyclic aromatic hydrocarbons (PAH) in superficial water from a tropical estuarine system: Distribution, seasonal variations, sources and ecological risk assessment.

    Science.gov (United States)

    Santos, Ewerton; Souza, Michel R R; Vilela Junior, Antônio R; Soares, Laiane S; Frena, Morgana; Alexandre, Marcelo R

    2018-02-01

    This study aimed to evaluate the PAH distribution, sources, seasonal variations and ecological risk assessment in superficial water from the Japaratuba River, Brazil. PAH concentrations ranged from 4 to 119ngL -1 . It was observed that the PAH total concentrations and profiles showed significant differences when comparing the dry season (summer) with the rainy season (winter). Furthermore, most of the PAH originated from pyrogenic sources in the winter, whereas a mixture of sources was observed in the summer. PAH concentration levels found in this study were considered lower than those obtained in other estuarine systems. Ecological risk assessment was determined for individual PAH, based on the risk quotient (RQ) to evaluate the risk of aquatic biota's exposure to PAH. Results suggested that the Japaratuba River has achieved a moderate degree of ecological risk for high molecular weight, showing the importance of identifying these carcinogenic and mutagenic compounds in aquatic systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Seasonal and Daily Variations of Subsurface Velocity Revealed by the Air-gun Source in Binchuan, Yunnan, China

    Science.gov (United States)

    Luan, Y.; Yang, H.; Wang, B.

    2017-12-01

    We derive temporal variations of subsurface structure using a large-volume air-gun source excited in Binchuan, Yunnan, southwest China, the first transmitting seismic station that can generate high-quality repeating waveforms. The data were collected between January 2013 and December 2015 that were recorded by 40 stations within 150 km, including permanent and newly deployed air-gun array stations. Firstly, we conduct cluster analysis using the waveforms at the nearest station and find the clustering result is not only governed by the water level of the reservoir, but also has seasonal variations. Furthermore, we use the records of the nearest station to approximate the source time functions and then retrieve empirical Green's functions (EGF) by deconvolution. Then we obtain travel time difference by comparing the EGF. The travel time difference exhibits clear seasonal variation, and the pattern correlates the best with surface air temperature. The increasing temperature coincides with increasing delay time i.e. decreasing seismic velocity. We interpret the observed seasonal variation of subsurface velocity is partly caused by thermo-elastic strain. However, our calculated thermo-elastic strain is only half in amplitude of the observed strain, indicating other factors such as precipitation and ground water level may play a role in the subsurface changes. Moreover, we derive the daily variation of subsurface velocity in December 2015 when air-gun shots were made in every hour. The delay time clearly correlates with the barometric pressure change and the tidal strain. Here we demonstrate that both long-term (seasonal) and short-term (daily) structural variations can be derived using the newly constructed active source, which is a powerful tool to advance our understanding of rheological properties of the crust as well as well processes associated with earthquakes and other natural hazards.

  14. Sources of variation and genetic profile of spontaneous, out-of-season ovulatory activity in the Chios sheep

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    Kouttos Athanasios

    2003-01-01

    Full Text Available Abstract Organising the breeding plan of a seasonally breeding species, such as sheep, presents a challenge to farmers and the industry as a whole, since both economical and biological considerations need to be carefully balanced. Understanding the breeding activity of individual animals becomes a prerequisite for a successful breeding program. This study set out to investigate the sources of variation and the genetic profile of the spontaneous, out-of-season ovulatory activity of ewes of the Chios dairy sheep breed in Greece. The definition of the trait was based on blood progesterone levels, measured before exposing the ewes to rams, which marks the onset of the usual breeding season. Data were 707 records, taken over two consecutive years, of 435 ewes kept at the Agricultural Research Station of Chalkidiki in northern Greece. When all available pedigree was included, the total number of animals involved was 1068. On average, 29% of all ewes exhibited spontaneous, out-of-season ovulatory activity, with no substantial variation between the years. Significant sources of systematic variation were the ewe age and live weight, and the month of previous lambing. Older, heavier ewes, that had lambed early the previous autumn, exhibited more frequent activity. Heritability estimates were 0.216 (± 0.084 with a linear and 0.291 with a threshold model. The latter better accounts for the categorical nature of the trait. The linear model repeatability was 0.230 (± 0.095. The results obtained in this study support the notion that spontaneous out-of-season ovulatory activity can be considered in the development of a breeding plan for the Chios sheep breed.

  15. Seasonal Variation and Sources of Dissolved Nutrients in the Yellow River, China

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    Yao Gong

    2015-08-01

    Full Text Available The rapid growth of the economy in China has caused dramatic growth in the industrial and agricultural development in the Yellow River (YR watershed. The hydrology of the YR has changed dramatically due to the climate changes and water management practices, which have resulted in a great variation in the fluxes of riverine nutrients carried by the YR. To study these changes dissolved nutrients in the YR were measured monthly at Lijin station in the downstream region of the YR from 2002 to 2004. This study provides detailed information on the nutrient status for the relevant studies in the lower YR and the Bohai Sea. The YR was enriched in nitrate (average 314 μmol·L−1 with a lower concentration of dissolved silicate (average 131 μmol·L−1 and relatively low dissolved phosphate (average 0.35 μmol·L−1. Nutrient concentrations exhibited substantial seasonal and yearly variations. The annual fluxes of dissolved inorganic nitrogen, phosphate, and silicate in 2004 were 5.3, 2.5, and 4.2 times those in 2002, respectively, primarily due to the increase in river discharge. The relative contributions of nutrient inputs to nitrogen in the YR were: wastewater > fertilizer > atmospheric deposition > soil; while to phosphorus were: wastewater > fertilizer > soil > atmospheric deposition. The ratios of N, P and Si suggest that the YR at Lijin is strongly P-limited with respect to potential phytoplankton growth.

  16. Atmospheric aerosols in Rome, Italy: sources, dynamics and spatial variations during two seasons

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    C. Struckmeier

    2016-12-01

    both sites. While they were observed every day at the urban location, at the suburban location they were only found under favourable meteorological conditions, but were independent of advection of the Rome emission plume. Particles from sources in the metropolitan area of Rome and particles advected from outside Rome contributed 42–70 and 30–58 % to the total measured PM1, respectively. Apart from the general aerosol characteristics, in this study the properties (e.g. emission strength and dynamics (e.g. temporal behaviour of each identified aerosol type is investigated in detail to provide a better understanding of the observed seasonal and spatial differences.

  17. Seasonal variation, flux estimation, and source analysis of dissolved emerging organic contaminants in the Yangtze Estuary, China.

    Science.gov (United States)

    Zhao, Heng; Cao, Zhen; Liu, Xue; Zhan, Yi; Zhang, Jing; Xiao, Xi; Yang, Yi; Zhou, Junliang; Xu, Jiang

    2017-12-15

    The occurrence and seasonal variation of 24 dissolved emerging organic contaminants in the Yangtze Estuary were studied, including 12 non-antibiotic pharmaceuticals, seven sulfonamides, two macrolides and three chloramphenicols. Sulfadiazine, erythromycin, thiamphenicol and paracetamol were the primary contaminants in sulfonamides, macrolides, chloramphenicols and non-antibiotic pharmaceutical groups, respectively. Compared to the concentrations at Datong, chloramphenicols at Xuliujing were significantly higher in autumn and winter, while macrolides were lower in spring. Based on the flux estimation, approximately 37.1 tons of sulfonamides, 17.4 tons of macrolides, 79.2 tons of chloramphenicols and 14.1 tons of non-antibiotic pharmaceuticals were discharged into the Yangtze Estuary from June 2013 to May 2014. However, the total flux from the Huangpu River only represented 5% of the total. The pharmaceutical sources were speculated on by analyzing the seasonal variations in pharmaceutical concentrations and fluxes at various sites. Both environmental and social factors might affect the fluxes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. The occurrence and distribution of antibiotics in Lake Chaohu, China: seasonal variation, potential source and risk assessment.

    Science.gov (United States)

    Tang, Jun; Shi, Taozhong; Wu, Xiangwei; Cao, Haiqun; Li, Xuede; Hua, Rimao; Tang, Feng; Yue, Yongde

    2015-03-01

    The distribution and seasonal variation of fifteen antibiotics belonging to three classes (sulfonamides, fluoroquinolones and tetracyclines) were investigated in Lake Chaohu, China. The concentrations of the selected antibiotics in the surface water, eight major inflowing rivers and sewage treatment plant (STP) samples were analyzed by UPLC-MS/MS. The results indicated that sulfamethoxazole and ofloxacin were the predominant antibiotics, with maximum concentrations of 95.6 and 383.4ngL(-1), respectively, in the river samples. In Lake Chaohu, the western inflowing rivers (the Nanfei and Shiwuli Rivers) were the primary import routes for the antibiotics, and the domestic effluent from four STPs were considered the primary source of the antibiotics. The level of antibiotics in Lake Chaohu clearly varied with seasonal changes, and the highest detectable frequencies and mean concentrations were found during the winter. The quality of water downstream of Lake Chaohu was influenced by the lake, and the results of risk assessment of the antibiotics on aquatic organisms suggested that sulfamethoxazole, ofloxacin, ciprofloxacin and enrofloxacin in the surface water of Lake Chaohu and inflowing rivers might pose a high risk to algae and plants. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Seasonal variation in sports participation.

    Science.gov (United States)

    Schüttoff, Ute; Pawlowski, Tim

    2018-02-01

    This study explores indicators describing socio-demographics, sports participation characteristics and motives which are associated with variation in sports participation across seasons. Data were drawn from the German Socio-Economic Panel which contains detailed information on the sports behaviour of adults in Germany. Overall, two different measures of seasonal variation are developed and used as dependent variables in our regression models. The first variable measures the coefficient of (seasonal) variation in sport-related energy expenditure per week. The second variable measures whether activity drops below the threshold as defined by the World Health Organization (WHO). Results suggest that the organisational setting, the intensity and number of sports practised, and the motive for participation are strongly correlated with the variation measures used. For example, both, participation in a sports club and a commercial facility, are associated with reduced seasonal variation and a significantly higher probability of participating at a volume above the WHO threshold across all seasons. These findings give some impetus for policymaking and the planning of sports programmes as well as future research directions.

  20. Seasonal variations and source apportionment of atmospheric PM2.5-bound polycyclic aromatic hydrocarbons in a mixed multi-function area of Hangzhou, China.

    Science.gov (United States)

    Lu, Hao; Wang, Shengsheng; Li, Yun; Gong, Hui; Han, Jingyi; Wu, Zuliang; Yao, Shuiliang; Zhang, Xuming; Tang, Xiujuan; Jiang, Boqiong

    2017-07-01

    To reveal the seasonal variations and sources of PM 2.5 -bound polycyclic aromatic hydrocarbons (PAHs) during haze and non-haze episodes, daily PM 2.5 samples were collected from March 2015 to February 2016 in a mixed multi-function area in Hangzhou, China. Ambient concentrations of 16 priority-controlled PAHs were determined. The sums of PM 2.5 -bound PAH concentrations during the haze episodes were 4.52 ± 3.32 and 13.6 ± 6.29 ng m -3 in warm and cold seasons, respectively, which were 1.99 and 1.49 times those during the non-haze episodes. Four PAH sources were identified using the positive matrix factorization model and conditional probability function, which were vehicular emissions (45%), heavy oil combustion (23%), coal and natural gas combustion (22%), and biomass combustion (10%). The four source concentrations of PAHs consistently showed higher levels in the cold season, compared with those in the warm season. Vehicular emissions were the most considerable sources that result in the increase of PM 2.5 -bound PAH levels during the haze episodes, and heavy oil combustion played an important role in the aggravation of haze pollution. The analysis of air mass back trajectories indicated that air mass transport had an influence on the PM 2.5 -bound PAH pollution, especially on the increased contributions from coal combustion and vehicular emissions in the cold season.

  1. PM10-bound polycyclic aromatic hydrocarbons in Chiang Mai (Thailand): Seasonal variations, source identification, health risk assessment and their relationship to air-mass movement

    Science.gov (United States)

    Wiriya, Wan; Prapamontol, Tippawan; Chantara, Somporn

    2013-04-01

    This study aims to analyze the seasonal variations of PM10-bound polycyclic aromatic hydrocarbons (PAHs) for an estimation of the human health risk and identification of their possible sources. Ninety four PM10 samples were collected during the dry and wet seasons of 2010 and the dry season of 2011 in Chiang Mai, Thailand, and analyzed for 16 PAHs by gas chromatography-mass spectrometry. The average PM10 concentrations were 104.91 ± 32.70, 13.28 ± 11.34 and 36.24 ± 19.16 μg/m3 in dry season of 2010, wet season of 2010 and dry season of 2011, respectively, while the average 16-PAHs concentrations were 25.87 ± 10.13, 3.12 ± 2.18 and 4.58 ± 2.18 ng/m3, respectively. Correlations of PM10 and total PAHs concentrations were relatively high during all seasons (r > 0.796). In addition, PM10 concentrations were highly correlated with carcinogenic PAHs (r = 0.927) during the dry season of 2010, indicating that carcinogenic compounds were dominant in the particulate PAHs and could be generated from open burning, usually conducted in the dry season. The average PM10 concentration in the dry season of 2011 was much lower than that in 2010 and lower than the annual average of the past 12 years (48.17 μg/m3) because of the unusually high amount of rain precipitation and low open burning activity in this year. According to the accumulated number of hot spots occurring in northern part of Thailand, approximately 19,000 spots were found in the dry season of 2010, while only 6,600 spots were found in the dry season of 2011. It can be seen that larger scale open burning activities were performed in the dry season of 2010 than in the dry season of 2011. The value of toxicity equivalent concentration from PAHs in the dry season of 2010 was higher than that of the wet season of 2010 and the dry season of 2011. This is obviously related to concentrations of PM10 and PAHs. Diagnostic ratio and principal component analysis were used to find out the sources of PM10-bound PAHs. It was

  2. Seasonal variations and sources of atmospheric polycyclic aromatic hydrocarbons and organochlorine compounds in a high-altitude city: Evidence from four-year observations

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Ping; Wang, Xiaoping; Sheng, Jiujiang; Wang, Hailong; Yuan, Xiaohua; He, Yuanqing; Qian, Yun; Yao, Tandong

    2018-02-01

    Lijiang is a high-altitude city located on the eastern fringe of the Tibetan Plateau, with complex seasonal atmospheric circulations (i.e. westerly wind, Indian Monsoon, and East Asia Monsoon). Very few previous studies have focused on seasonal variations and sources of organic pollutants in Lijiang. In this study, a four-year air campaign from June 2009 to July 2013 was conducted to investigate the temporal trends and the sources of polycyclic aromatic hydrocarbons (PAHs) and organochlorine compounds [including organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs)]. The atmospheric PAH concentrations in winter are 2-3 times of those in summer, probably because of the combined result of enhanced local emission and long-range atmospheric transport (LRAT) during winter. Traffic pollution was the primary local source of PAHs, while biomass burning is the dominant LRAT source. Different from PAHs, OCPs and PCBs mainly underwent LRAT to reach Lijiang. The peak concentrations of most of OCPs occurred in pre-monsoon season and winter, which are carried by air masses from Myanmar and India through westerly winds. As compared with other sites of the Tibetan Plateau, without the direct barrier of the Himalaya, Lijiang is easily contaminated by the incursion of polluted air masses.

  3. Seasonal variations in high time-resolved chemical compositions, sources, and evolution of atmospheric submicron aerosols in the megacity Beijing

    Directory of Open Access Journals (Sweden)

    W. Hu

    2017-08-01

    Full Text Available A severe regional haze problem in the megacity Beijing and surrounding areas, caused by fast formation and growth of fine particles, has attracted much attention in recent years. In order to investigate the secondary formation and aging process of urban aerosols, four intensive campaigns were conducted in four seasons between March 2012 and March 2013 at an urban site in Beijing (116.31° E, 37.99° N. An Aerodyne high-resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS was deployed to measure non-refractory chemical components of submicron particulate matter (NR-PM1. The average mass concentrations of PM1 (NR-PM1+black carbon were 45.1 ± 45.8, 37.5 ± 31.0, 41.3 ± 42.7, and 81.7 ± 72.4 µg m−3 in spring, summer, autumn, and winter, respectively. Organic aerosol (OA was the most abundant component in PM1, accounting for 31, 33, 44, and 36 % seasonally, and secondary inorganic aerosol (SNA, sum of sulfate, nitrate, and ammonium accounted for 59, 57, 43, and 55 % of PM1 correspondingly. Based on the application of positive matrix factorization (PMF, the sources of OA were obtained, including the primary ones of hydrocarbon-like (HOA, cooking (COA, biomass burning OA (BBOA and coal combustion OA (CCOA, and secondary component oxygenated OA (OOA. OOA, which can be split into more-oxidized (MO-OOA and less-oxidized OOA (LO-OOA, accounted for 49, 69, 47, and 50 % in four seasons, respectively. Totally, the fraction of secondary components (OOA+SNA contributed about 60–80 % to PM1, suggesting that secondary formation played an important role in the PM pollution in Beijing, and primary sources were also non-negligible. The evolution process of OA in different seasons was investigated with multiple metrics and tools. The average carbon oxidation states and other metrics show that the oxidation state of OA was the highest in summer, probably due to both strong photochemical and aqueous-phase oxidations

  4. Seasonal variations in high time-resolved chemical compositions, sources, and evolution of atmospheric submicron aerosols in the megacity Beijing

    Science.gov (United States)

    Hu, Wei; Hu, Min; Hu, Wei-Wei; Zheng, Jing; Chen, Chen; Wu, Yusheng; Guo, Song

    2017-08-01

    A severe regional haze problem in the megacity Beijing and surrounding areas, caused by fast formation and growth of fine particles, has attracted much attention in recent years. In order to investigate the secondary formation and aging process of urban aerosols, four intensive campaigns were conducted in four seasons between March 2012 and March 2013 at an urban site in Beijing (116.31° E, 37.99° N). An Aerodyne high-resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS) was deployed to measure non-refractory chemical components of submicron particulate matter (NR-PM1). The average mass concentrations of PM1 (NR-PM1+black carbon) were 45.1 ± 45.8, 37.5 ± 31.0, 41.3 ± 42.7, and 81.7 ± 72.4 µg m-3 in spring, summer, autumn, and winter, respectively. Organic aerosol (OA) was the most abundant component in PM1, accounting for 31, 33, 44, and 36 % seasonally, and secondary inorganic aerosol (SNA, sum of sulfate, nitrate, and ammonium) accounted for 59, 57, 43, and 55 % of PM1 correspondingly. Based on the application of positive matrix factorization (PMF), the sources of OA were obtained, including the primary ones of hydrocarbon-like (HOA), cooking (COA), biomass burning OA (BBOA) and coal combustion OA (CCOA), and secondary component oxygenated OA (OOA). OOA, which can be split into more-oxidized (MO-OOA) and less-oxidized OOA (LO-OOA), accounted for 49, 69, 47, and 50 % in four seasons, respectively. Totally, the fraction of secondary components (OOA+SNA) contributed about 60-80 % to PM1, suggesting that secondary formation played an important role in the PM pollution in Beijing, and primary sources were also non-negligible. The evolution process of OA in different seasons was investigated with multiple metrics and tools. The average carbon oxidation states and other metrics show that the oxidation state of OA was the highest in summer, probably due to both strong photochemical and aqueous-phase oxidations. It was indicated by the good correlations

  5. Temporal and seasonal variations of black carbon in a highly polluted European city: Apportionment of potential sources and the effect of meteorological conditions.

    Science.gov (United States)

    Kucbel, Marek; Corsaro, Agnieszka; Švédová, Barbora; Raclavská, Helena; Raclavský, Konstantin; Juchelková, Dagmar

    2017-12-01

    Black carbon - a primary component of particulate matter emitted from an incomplete combustion of fossil fuels, biomass, and biofuels - has been found to have a detrimental effect on human health and the environment. Since black carbon emissions data are not readily available, no measures are implemented to reduce black carbon emissions. The temporal and seasonal variations of black carbon concentrations were evaluated during 2012-2014. The data were collected in the highly polluted European city - Ostrava, Czech Republic, surrounded by major highways and large industries. Significantly higher black carbon concentrations were obtained in Ostrava, relative to other European cities and the magnitude was equivalent to the magnitude of black carbon concentrations measured in Poland and China. The data were categorized to heating and non-heating seasons based on the periodic pattern of daily and monthly average concentrations of black carbon. A higher black carbon concentration was obtained during heating season than non-heating season and was primarily associated with an increase in residential coal burning and meteorological parameters. The concentration of black carbon was found to be negatively correlated with temperature and wind speed, and positively correlated with the relative humidity. Other black carbon sources potentially included emissions from vehicle exhaust and the local steel-producing industry. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Multi-year (2004–2008 record of nonmethane hydrocarbons and halocarbons in New England: seasonal variations and regional sources

    Directory of Open Access Journals (Sweden)

    R. S. Russo

    2010-05-01

    Full Text Available Multi-year time series records of C2-C6 alkanes, C2-C4 alkenes, ethyne, isoprene, C6-C8 aromatics, trichloroethene (C2HCl3, and tetrachloroethene (C2Cl4 from canister samples collected during January 2004–February 2008 at the University of New Hampshire (UNH AIRMAP Observatory at Thompson Farm (TF in Durham, NH are presented. The objectives of this work are to identify the sources of nonmethane hydrocarbons (NMHCs and halocarbons observed at TF, characterize the seasonal and interannual variability in ambient mixing ratios and sources, and estimate regional emission rates of NMHCs. Analysis of correlations and comparisons with emission ratios indicated that a ubiquitous and persistent mix of emissions from several anthropogenic sources is observed throughout the entire year. The highest C2-C8 anthropogenic NMHC mixing ratios were observed in mid to late winter. Following the springtime minimums, the C3-C6 alkanes, C7-C8 aromatics, and C2HCl3 increased in early to mid summer, presumably reflecting enhanced evaporative emissions. Mixing ratios of C2Cl4 and C2HCl3 decreased by 0.7±0.2 and 0.3±0.05 pptv/year, respectively, which is indicative of reduced usage and emissions of these halogenated solvents. Emission rates of C3-C8 NMHCs were estimated to be 109 to 1010 molecules cm−2 s−1 in winter 2006. The emission rates extrapolated to the state of New Hampshire and New England were ~2–60 Mg/day and ~12–430 Mg/day, respectively. Emission rates of benzene, toluene, ethylbenzene, xylenes, and ethyne in the 2002 and 2005 EPA National Emissions Inventories were within ±50% of the TF emission rates.

  7. Aerosol characterization over the southeastern United States using high resolution aerosol mass spectrometry: spatial and seasonal variation of aerosol composition, sources, and organic nitrates

    Science.gov (United States)

    Xu, L.; Suresh, S.; Guo, H.; Weber, R. J.; Ng, N. L.

    2015-04-01

    We deployed a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and an Aerosol Chemical Speciation Monitor (ACSM) to characterize the chemical composition of submicron non-refractory particles (NR-PM1) in the southeastern US. Measurements were performed in both rural and urban sites in the greater Atlanta area, GA and Centreville, AL for approximately one year, as part of Southeastern Center of Air Pollution and Epidemiology study (SCAPE) and Southern Oxidant and Aerosol Study (SOAS). Organic aerosol (OA) accounts for more than half of NR1 mass concentration regardless of sampling sites and seasons. Positive matrix factorization (PMF) analysis of HR-ToF-AMS measurements identified various OA sources, depending on location and season. Hydrocarbon-like OA (HOA) and cooking OA (COA) have important but not dominant contributions to total OA in urban sites. Biomass burning OA (BBOA) concentration shows a distinct seasonal variation with a larger enhancement in winter than summer. We find a good correlation between BBOA and brown carbon, indicating biomass burning is an important source for brown carbon, although an additional, unidentified brown carbon source is likely present at the rural Yorkville site. Isoprene-derived OA (Isoprene-OA) is only deconvolved in warmer months and contributes 18-36% of total OA. The presence of Isoprene-OA factor in urban sites is more likely from local production in the presence of NOx than transport from rural sites. More-oxidized and less-oxidized oxygenated organic aerosol (MO-OOA and LO-OOA, respectively) are dominant fractions (47-79%) of OA in all sites. MO-OOA correlates well with ozone in summer, but not in winter, indicating MO-OOA sources may vary with seasons. LO-OOA, which reaches a daily maximum at night, correlates better with estimated nitrate functionality from organic nitrates than total nitrates. Based on the HR-ToF-AMS measurements, we estimate that the nitrate functionality from organic nitrates

  8. Water-soluble ions in atmospheric aerosols measured in five sites in the Yangtze River Delta, China: Size-fractionated, seasonal variations and sources

    Science.gov (United States)

    Wang, Honglei; Zhu, Bin; Shen, Lijuan; Xu, Honghui; An, Junlin; Xue, Guoqiang; Cao, Jinfei

    2015-12-01

    In order to investigate the regional variations of water-soluble ions (WSIs), size-resolved measurement of aerosol particles and WSIs was conducted by using Anderson Sampler and Ion Chromatography at five sites (Nanjing, Suzhou, Lin'an, Hangzhou and Ningbo) in the Yangtze River Delta (YRD) region, China in the Autumn of 2012 and Winter, Spring and Summer of 2013. WSIs exhibited obvious seasonal variations due to the monsoon conversion, with the highest level in winter and lowest level in summer. The aerosol mass concentrations and WSIs in different size segments varied with four seasons. The dominant ions concentrations in PM2.1 ranked in the order of SO42- > NO3- > NH4+ > Cl- > K+ > Ca2+, and the dominant ions concentrations in PM2.1-10 ranked in the order of Ca2+ > NO3- > SO42- > Cl- > NH4+ > Na+. The size spectra of mass and WSIs concentration peaked mostly at 0.43-0.65 μm in four seasons. The concentration discrepancies of WSIs in different cities were caused by the geographic locations and emission source. It's belonged to ammonium-rich distribution in PM2.1 and ammonium-poor distribution in PM2.1-10 in the YRD region. The impact of temperature on mass concentrations of NO3- and NH4+ in PM2.1 were stronger than those in PM2.1-10. PCA analysis shows that the sources of WSIs dominant by anthropogenic sources, soil particles or falling dust, sea salt and burning process.

  9. Diurnal and Seasonal Variations in the Net Ecosystem CO2 Exchange of a Pasture in the Three-River Source Region of the Qinghai-Tibetan Plateau.

    Directory of Open Access Journals (Sweden)

    Bin Wang

    Full Text Available Carbon dioxide (CO2 exchange between the atmosphere and grassland ecosystems is very important for the global carbon balance. To assess the CO2 flux and its relationship to environmental factors, the eddy covariance method was used to evaluate the diurnal cycle and seasonal pattern of the net ecosystem CO2 exchange (NEE of a cultivated pasture in the Three-River Source Region (TRSR on the Qinghai-Tibetan Plateau from January 1 to December 31, 2008. The diurnal variations in the NEE and ecosystem respiration (Re during the growing season exhibited single-peak patterns, the maximum and minimum CO2 uptake observed during the noon hours and night; and the maximum and minimum Re took place in the afternoon and early morning, respectively. The minimum hourly NEE rate and the maximum hourly Re rate were -7.89 and 5.03 μmol CO2 m-2 s-1, respectively. The NEE and Re showed clear seasonal variations, with lower values in winter and higher values in the peak growth period. The highest daily values for C uptake and Re were observed on August 12 (-2.91 g C m-2 d-1 and July 28 (5.04 g C m-2 day-1, respectively. The annual total NEE and Re were -140.01 and 403.57 g C m-2 year-1, respectively. The apparent quantum yield (α was -0.0275 μmol μmol-1 for the entire growing period, and the α values for the pasture's light response curve varied with the leaf area index (LAI, air temperature (Ta, soil water content (SWC and vapor pressure deficit (VPD. Piecewise regression results indicated that the optimum Ta and VPD for the daytime NEE were 14.1°C and 0.65 kPa, respectively. The daytime NEE decreased with increasing SWC, and the temperature sensitivity of respiration (Q10 was 3.0 during the growing season, which was controlled by the SWC conditions. Path analysis suggested that the soil temperature at a depth of 5 cm (Tsoil was the most important environmental factor affecting daily variations in NEE during the growing season, and the photosynthetic photon

  10. Seasonal Variations in Mercury's Dayside Calcium Exosphere

    Science.gov (United States)

    Burger, Matthew H.; Killen, Rosemary M.; McClintock, William E.; Merkel, Aimee W.; Vervack, Ronald J., Jr.; Cassidy, Timothy A.; Sarantos, Menelaos

    2014-01-01

    The Mercury Atmospheric and Surface Composition Spectrometer on the MESSENGER spacecraft has observed calcium emission in Mercury's exosphere on a near-daily basis since March 2011. During MESSENGER's primary and first extended missions (March 2011 - March 2013) the dayside calcium exosphere was measured over eight Mercury years. We have simulated these data with a Monte Carlo model of exospheric source processes to show that (a) there is a persistent source of energetic calcium located in the dawn equatorial region, (b) there is a seasonal dependence in the calcium source rate, and (c) there are no obvious year-to-year variations in the near-surface dayside calcium exosphere. Although the precise mechanism responsible for ejecting the calcium has not yet been determined, the most likely process is the dissociation of Ca-bearing molecules produced in micrometeoroid impact plumes to form energetic, escaping calcium atoms.

  11. Seasonal and spatial variation of diffuse (non-point) source zinc pollution in a historically metal mined river catchment, UK

    Energy Technology Data Exchange (ETDEWEB)

    Gozzard, E., E-mail: emgo@ceh.ac.uk [Hydrogeochemical Engineering Research and Outreach Group, School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom); Mayes, W.M., E-mail: W.Mayes@hull.ac.uk [Hydrogeochemical Engineering Research and Outreach Group, School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom); Potter, H.A.B., E-mail: hugh.potter@environment-agency.gov.uk [Environment Agency England and Wales, c/o Institute for Research on Environment and Sustainability, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom); Jarvis, A.P., E-mail: a.p.jarvis@ncl.ac.uk [Hydrogeochemical Engineering Research and Outreach Group, School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom)

    2011-10-15

    Quantifying diffuse sources of pollution is becoming increasingly important when characterising river catchments in entirety - a prerequisite for environmental management. This study examines both low and high flow events, as well as spatial variability, in order to assess point and diffuse components of zinc pollution within the River West Allen catchment, which lies within the northern England lead-zinc Orefield. Zinc levels in the river are elevated under all flow regimes, and are of environmental concern. Diffuse components are of little importance at low flow, with point source mine water discharges dominating instream zinc concentration and load. During higher river flows 90% of the instream zinc load is attributed to diffuse sources, where inputs from resuspension of metal-rich sediments, and groundwater influx are likely to be more dominant. Remediating point mine water discharges should significantly improve water quality at lower flows, but contribution from diffuse sources will continue to elevate zinc flux at higher flows. - Highlights: > Zinc concentrations breach EU quality thresholds under all river flow conditions. > Contributions from point sources dominate instream zinc dynamics in low flow. > Contributions from diffuse sources dominate instream zinc dynamics in high flow. > Important diffuse sources include river-bed sediment resuspension and groundwater influx. > Diffuse sources would still create significant instream pollution, even with point source treatment. - Diffuse zinc sources are an important source of instream contamination to mine-impacted rivers under varying flow conditions.

  12. Seasonal Variation of Arsenic Concentration in Natural Water of the Source Area of the Yellow River on the Qinghai-Tibet Plateau, China

    Science.gov (United States)

    Yu, C.; Wen, L.; Yu, Z.

    2017-12-01

    Seasonal variation in the arsenic (As) concentration of natural water has been studied the first time in the source area of the Yellow River (SAYR) in Tibet, China. Samples were collected in the lake, river and spring across the whole area in April (spring) and July (summer), 2014. In April the average values of arsenic concentration in SAYR from high to low were: lake (38.1μg/L, n=47, range 8.6-131.0μg/L) > river (24.3μg/L, n=83, range 4.3-77.1μg/L) > spring (19.1μg/L, n=12, range 12.0-29.4μg/L). In July the same order of the average values of arsenic concentration in SAYR was found: lake (14.1μg/L, n=57, range 5.8-68.5μg/L) > river (7.3μg/L, n=106, range 3.6-22.9μg/L)> spring (6.7μg/L, n=9, range 4.8-8.2μg/L).The average arsenic concentrations in April were almost three times higher than those in July. In both season, the higher concentrations of arsenic were distributed in the upper reaches above the two biggest lakes of Gyaring and Ngoring Lakes in SAYR. The two big lakes buffered the naturally generated arsenic concentration in surface water, suggesting the important ecological role of the lakes. Generally, the lower concentrations in July probably were due to 1. the dilution effect of the precipitation; 2 the change of water sources. In April when the permafrost and mountain snow started to thaw and melt, ground water with high arsenic concentration was the main water source with high concentration of arsenic; but in July, with the increase of the temperature, mountain snow, permafrost would contribute more than in April, in addition, the main arsenic contributor groundwater was diluted by the precipitation recharge. Since in spring, lake and river water arsenic concentration decreased with almost the same magnitude., assuming the dilution effect dominant. The exported arsenic from SAYR in April (903.4Kg) were twice more than it in July (449.1Kg), because the flowrates were similar in the two months, the water source of the runoff components was

  13. The contribution of component variation and phytoplankton growth to the distribution variation of chromophoric dissolved organic matter content in a mid-latitude subtropical drinking water source reservoir for two different seasons.

    Science.gov (United States)

    Sun, Qiyuan; Jiang, Juan; Zheng, Yuyi; Wang, Feifeng; Wu, Chunshan; Xie, Rong-Rong

    2017-07-01

    The distribution variation in chromophoric dissolved organic matter (CDOM) content in mid-latitude subtropical drinking water source reservoirs (MDWSRs) has great significance in the security of aquatic environments and human health. CDOM distribution is heavily influenced by biogeochemical processes and anthropogenic activity. However, little is known regarding the impact of component variation and phytoplankton growth on CDOM distribution variation in MDWSR. Therefore, samples were collected from a representative MDWSR (the Shanzai Reservoir) for analysis. CDOM absorption and fluorescence coupling with parallel factor analysis were measured and calculated. The results indicated that only two CDOM components were found in the surface water of Shanzai Reservoir, fulvic acid, and high-excitation tryptophan, originating from terrestrial and autochthonous sources, respectively. The types of components did not change with the season. The average molecular weight of CDOM increased in proportion to its fulvic acid content. The distribution variation in CDOM content mainly resulted from the variation in two CDOM components in summer and from high-excitation tryptophan in winter. Phytoplankton growth strongly influenced the distribution variation of CDOM content in summer; the metabolic processes of Cyanobacteria and Bacillariophyta consumed fulvic acid, while that of Cryptophyta produced high-excitation tryptophan.

  14. Seasonal Variations in Color Preference.

    Science.gov (United States)

    Schloss, Karen B; Nelson, Rolf; Parker, Laura; Heck, Isobel A; Palmer, Stephen E

    2017-08-01

    We investigated how color preferences vary according to season and whether those changes could be explained by the ecological valence theory (EVT). To do so, we assessed the same participants' preferences for the same colors during fall, winter, spring, and summer in the northeastern United States, where there are large seasonal changes in environmental colors. Seasonal differences were most pronounced between fall and the other three seasons. Participants liked fall-associated dark-warm colors-for example, dark-red, dark-orange (brown), dark-yellow (olive), and dark-chartreuse-more during fall than other seasons. The EVT could explain these changes with a modified version of Palmer and Schloss' (2010) weighted affective valence estimate (WAVE) procedure that added an activation term to the WAVE equation. The results indicate that color preferences change according to season, as color-associated objects become more/less activated in the observer. These seasonal changes in color preferences could not be characterized by overall shifts in weights along cone-contrast axes. Copyright © 2016 Cognitive Science Society, Inc.

  15. Water-soluble ions in atmospheric aerosols measured in Xi'an, China: Seasonal variations and sources

    Science.gov (United States)

    Zhang, T.; Cao, J. J.; Tie, X. X.; Shen, Z. X.; Liu, S. X.; Ding, H.; Han, Y. M.; Wang, G. H.; Ho, K. F.; Qiang, J.; Li, W. T.

    2011-10-01

    Daily PM 2.5 and water-soluble inorganic ions (Na +, NH 4+, K +, Mg 2+, Ca 2+, Cl -, NO 3- and SO 42-) were collected in Xi'an (34.23°N, 108.88°E), China from March 2006 to March 2007. PM 2.5 was collected using battery-powered mini-volume samplers. And the ions were determined by ion chromatography from the measured aerosol mass. The annual average mass concentration of PM 2.5 was found to be 194.1 ± 78.6 μg m - 3 , which exceeded substantially the international guidelines for health concerns. The seasonal average mass concentration of PM 2.5 was highest in winter (266.8 μg m - 3 ) and lowest in summer (138.6 μg m - 3 ). The three highest abundant ions were SO 42-, NO 3-, and NH 4+, with average concentrations of 35.6 ± 19.5 μg m - 3 , 16.4 ± 10.1 μg m - 3 , and 11.4 ± 6.8 μg m - 3 , which were accounted for 18.7%, 8.0%, and 5.7% of the PM 2.5 mass, respectively. The major ions were in the species of (NH 4) 2SO 4, NH 4HSO 4 and NH 4NO 3, and their concentrations were highest in winter, due to high coal combustion. The concentrations of Ca 2+ were higher in spring than other seasons, due to the higher mineral dust concentrations. Ca 2+ was strongly correlated with CO 32-, which was calculated as the difference in the measured cations minus anions. Ion balance calculations indicate that the PM 2.5 was acidic, and this result is consistent with the measurement of pH values. Sulfur oxidation ratio was higher in summer and autumn, which implies that the formation of secondary sulfate-rich particles is favored by warm and relatively moist weather. Nitrogen oxidation ratio was highest in autumn.

  16. seasonal variation in chromium hexavalent and copper

    African Journals Online (AJOL)

    Admin

    Seasonal variation in heavy metal contamination of groundwater in the Jimeta- Yola area ... animal feedlots, industrial waste and food processing ...... and conservation of groundwater quality; a) ... significant role of hydrous Mn and Fe oxides.

  17. Nutrients and clam contamination by Escherichia coli in a meso-tidal coastal lagoon: Seasonal variation in counter cycle to external sources

    International Nuclear Information System (INIS)

    Botelho, Maria João; Soares, Florbela; Matias, Domitília; Vale, Carlos

    2015-01-01

    Highlights: • Sources of nutrients and E. coli in Ria Formosa linked to tourism in summer. • Lower nutrient values and clam contamination by E. coli in summer. • Bactericide effect of temperature and solar radiation causes lower E. coli. • Higher biological consumption of nutrients in warmer periods. • Results mirror possible effects of climate changes on coastal lagoons. - Abstract: The clam Ruditapes decussatus was transplanted from a natural recruitment area of Ria Formosa to three sites, surveyed for nutrients in water and sediments. Specimens were sampled monthly for determination of Escherichia coli, condition index and gonadal index. Higher nutrient values in low tide reflect drainage, anthropogenic sources or sediment regeneration, emphasising the importance of water mixing in the entire lagoon driven by the tide. Despite the increase of effluent discharges in summer due to tourism, nutrient concentrations and E. coli in clams were lower in warmer periods. The bactericide effect of temperature and solar radiation was better defined in clams from the inlet channel site than from sites closer to urban effluents. High temperature in summer and torrential freshwater inputs to Ria Formosa may anticipate climate change scenarios for south Europe. Seasonal variation of nutrients and clam contamination may thus point to possible alterations in coastal lagoons and their ecosystem services

  18. Seasonal variation, spatial distribution and source apportionment for polycyclic aromatic hydrocarbons (PAHs) at nineteen communities in Xi'an, China: The effects of suburban scattered emissions in winter.

    Science.gov (United States)

    Wang, Jingzhi; Cao, Junji; Dong, Zhibao; Guinot, Benjamin; Gao, Meiling; Huang, Rujin; Han, Yongming; Huang, Yu; Ho, Steven Sai Hang; Shen, Zhenxing

    2017-12-01

    Seasonal variation and spatial distribution of PM 2.5 bound polycyclic aromatic hydrocarbons (PAHs) were investigated at urban residential, commercial area, university, suburban region, and industry in Xi'an, during summer and winter time at 2013. Much higher levels of total PAHs were obtained in winter. Spatial distributions by kriging interpolations principle showed that relative high PAHs were detected in western Xi'an in both summer and winter, with decreasing trends in winter from the old city wall to the 2 nd -3rd ring road except for the suburban region and industry. Coefficients of diversity and statistics by SPSS method demonstrated that PAHs in suburban have significant differences (t winter and summer in urban, which different with the suburban. The coal combustion was the main source for PAHs in suburban region, which accounted for 46.6% in winter and sharp decreased to 19.2% in summer. Scattered emissions from uncontrolled coal combustion represent an important source of PAHs in suburban in winter and there were about 135 persons in Xi'an will suffer from lung cancer for lifetime exposure at winter levels. Further studies are needed to specify the effluence of the scattered emission in suburban to the city and to develop a strategy for controlling those emissions and lighten possible health effects. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Seasonal variations in sleep disorders of nurses.

    Science.gov (United States)

    Chang, Yuanmay; Lam, Calvin; Chen, Su-Ru; Sithole, Trevor; Chung, Min-Huey

    2017-04-01

    To investigate the difference between nurses and the general population regarding seasonal variations in sleep disorders during 2004-2008. The effects of season and group interaction on sleep disorders with regard to different comorbidities were also examined. Studies on seasonal variations in sleep disorders were mainly conducted in Norway for the general population. Furthermore, whether different comorbidities cause seasonal variations in sleep disorders in nurses remains unknown. A retrospective study. Data from the Taiwan National Health Insurance Research Database were used in generalised estimating equation Poisson distribution models to investigate the differences in sleep disorders between nurses and the general population diagnosed with sleep disorders (each n = 7643) as well as the interaction effects of sleep disorders between the groups with respect to different seasons. Furthermore, the interaction effects between groups and seasons on sleep disorders in the subgroups of comorbid anxiety disorders and depressive disorders were studied. Both the nurses and the general population had fewer outpatient visits for sleep disorders in winter than in other seasons. The nurses had fewer outpatient visits for sleep disorders than the general population did in each season. The nurses had more outpatient visits for sleep disorders in winter than in summer compared with the general population in the comorbid depressive disorder subgroup but not in the comorbid anxiety disorder subgroup. Nurses and the general population exhibited similar seasonal patterns of sleep disorders, but nurses had fewer outpatient visits for sleep disorders than the general population did in each season. For nurses with comorbid depressive disorders, outpatient visits for sleep disorders were more numerous in winter than in summer, potentially because nurses with comorbid depressive disorders are affected by shorter daylight exposure during winter. Depression and daylight exposure may

  20. One year online measurements of water-soluble ions at the industrially polluted town of Nanjing, China: Sources, seasonal and diurnal variations.

    Science.gov (United States)

    Wang, Honglei; An, Junlin; Cheng, Mengtian; Shen, Lijuan; Zhu, Bin; Li, Yi; Wang, Yuesi; Duan, Qing; Sullivan, Amy; Xia, Li

    2016-04-01

    Half-hourly mass concentrations water-soluble ions (WSIs) and PM2.5 were measured online a Rapid Collector of Fine Particles and Ion Chromatography system (RCFP-IC) and FH62C14 Continuous Particulate Monitor in Nanjing from October 18, 2013 to November 17, 2014. The WSIs concentration ranged from 7.07 to 333.42 μg m(-3) with an annual mean of 76.32 μg m(-3). The WSIs ranked in the order of SO4(2-) > NH4(+) > NO3(-) > Cl(-) > NO2(-) > K(+) > Ca(2+) > Na(+) > Mg(2+). The PM2.5 concentration ranged from 4.00 to 400 μg m(-3) with an annual mean of 83.58 μg m(-3). The concentrations of WSIs varied in the order of winter (115.77 μg m(-3)) > spring (76.10 μg m(-3)) > autumn (63.72 μg m(-3)) > summer (59.75 μg m(-3)), with the highest level in January (123.99 μg m(-3)) and lowest level in August (43.73 μg m(-3)). Different WSIs had distinct diurnal variations. The source analysis of the WSIs in the PCA/APCS mode illustrated that the sources consisted of secondary aerosol, coal combustion, mineral dust, biomass burning, traffic emissions and sea salt. In addition, there were seasonal variations amongst the various sources. The haze formation mechanism was different in summer and winter. The winter was dominated by NH4NO3 (18.56%), (NH4)2SO4 (28.63%), NH4(+) (11.27%), SO4(2-) (18.35%) and NO3(-) (13.13%), and by NH3 (25.93%), (NH4)2SO4 (13.37%), SO4(2-) (15.74%) and NO3(-) (9.97%) in summer. Consequently, the proportions of HCl, HNO3, NH4(+), SO4(2-) and NO3(-) were much larger during haze episodes in winter, while it was dominated by NH4NO3, NH4(+), (NH4)2SO4, SO4(2-) and NO3(-) during summer haze episodes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Seasonal variation and potential sources of Cryptosporidium contamination in surface waters of Chao Phraya River and Bang Pu Nature Reserve pier, Thailand.

    Science.gov (United States)

    Koompapong, Khuanchai; Sukthana, Yaowalark

    2012-07-01

    Using molecular techniques, a longitudinal study was conducted with the aims at identifying the seasonal difference of Cryptosporidium contamination in surface water as well as analyzing the potential sources based on species information. One hundred forty-four water samples were collected, 72 samples from the Chao Phraya River, Thailand, collected in the summer, rainy and cool seasons and 72 samples from sea water at Bang Pu Nature Reserve pier, collected before, during and after the presence of migratory seagulls. Total prevalence of Cryptosporidium contamination in river and sea water locations was 11% and 6%, respectively. The highest prevalence was observed at the end of rainy season continuing into the cool season in river water (29%) and in sea water (12%). During the rainy season, prevalence of Cryptosporidium was 4% in river and sea water samples, but none in summer season. All positive samples from the river was C. parvum, while C. meleagridis (1), and C. serpentis (1) were obtained from sea water. To the best of our knowledge, this is the first genetic study in Thailand of Cryptosporidium spp contamination in river and sea water locations and the first report of C. serpentis, suggesting that humans, household pets, farm animals, wildlife and migratory birds may be the potential sources of the parasites. The findings are of use for implementing preventive measures to reduce the transmission of cryptosporidiosis to both humans and animals.

  2. Source identification and seasonal variation of polycyclic aromatic hydrocarbons associated with atmospheric fine and coarse particles in the Metropolitan Area of Porto Alegre, RS, Brazil

    Science.gov (United States)

    Teixeira, Elba Calesso; Agudelo-Castañeda, Dayana M.; Fachel, Jandyra Maria Guimarães; Leal, Karen Alam; Garcia, Karine de Oliveira; Wiegand, Flavio

    2012-11-01

    The purpose of the present study was to evaluate the polycyclic aromatic hydrocarbons (PAHs) in fine (PM2.5) and coarse particles (PM2.5-10) in an urban and industrial area in the Metropolitan Area of Porto Alegre (MAPA), Brazil. Sixteen U.S. Environmental Protection Agency (EPA) priority polycyclic aromatic hydrocarbons (PAHs) were measured. Filters containing ambient air particulate were extracted with dichloromethane using Soxhlet. Extracts were later analyzed, for determining PAH concentrations, using a gaseous chromatograph coupled with a mass spectrometer (GC-MS). The polycyclic aromatic hydrocarbons (PAHs) were more concentrated in PM2.5 with an average of 70% of total PAHs in the MAPA. The target PAH apportionment among the main emission sources was carried out by diagnostic PAH concentration ratios, and principal component analysis (PCA). PAHs with higher molecular weight showed higher percentages in the fine particles in the MAPA. Based on the diagnostic ratios and PCA analysis, it may be concluded that the major contribution of PAHs was from vehicular sources (diesel and gasoline), especially in the PM2.5 fraction, as well as coal and wood burning. The winter/summer ratio in the PM2.5 and PM2.5-10 fractions in the MAPA was 3.1 and 1.8, respectively, revealing the seasonal variation of PAHs in the two fractions. The estimated toxicity equivalent factor (TEF), used to assess the contribution of the carcinogenic potency, confirms a significant presence of the moderately active carcinogenic PAHs BaP and DahA in the samples collected in the MAPA.

  3. Molecular distribution, seasonal variation, chemical transformation and sources of dicarboxylic acids and related compounds in atmospheric aerosols at remote marine Gosan site, Jeju Island

    Science.gov (United States)

    Kundu, S.; Kawamura, K.; Lee, M.

    2009-12-01

    : A homologous series of C2-C12 α, ω-dicarboxylic acids, ω-oxocarboxylic acids (C2-C9), pyruvic acid and α-dicarbonyls (C2-C3) were detected in atmospheric aerosols collected between April 2003 and April 2004 from remote marine Gosan site (33°29‧ N, 126°16‧ E) located in Jeju Island, South Korea. They were determined using a GC-FID and GC/MS. Total diacid concentration ranged from 130 to 1911 ng m-3 (av. 642 ng m-3), whereas total oxoacid concentration ranged from 7 to 155 ng m-3 (av. 43 ng m-3), and pyruvic acid and α-dicarbonyls ranged from 0.5 to 15 ng m-3 (av. 5 ng m-3) and 2-108 ng m-3 (av. 17.3 ng m-3), respectively. Oxalic (C2) acid was the most abundant in all seasons followed by malonic (C3) or succinic (C4) acid, and phthalic (Ph) acid. The concentration of diacids decreased with an increase in carbon number except for azelaic (C9) acid, which was more abundant than suberic (C8) acid. Glyoxylic acid was predominant ω-oxoacid contributing to 92% of total ω-oxoacid. Total diacids, oxoacids and dicarbonyls showed maximum concentrations in spring and occasionally in winter, while minimum concentrations were observed in summer. Air mass trajectory analysis suggests that either spring or winter maxima can be explained by strong continental outflow associated with cold front passages, while summer minima are associated with warm southerly flows, which transport clean marine air from low latitudes to Jeju Island. The comparison between total diacid concentration level of this study and other study results of urban and remote sites of East Asia reveals that Gosan site is more heavily influenced by the continental outflow from China. The seasonal variation of malonic/succinic (C3/C4), malic/succinic (hC4/C4), fumaric/maleic (F/M), oxalic/pyruvic (C2/Py) and oxalic/Glyoxal (C2/Gly) ratios showed maxima in summer due to an enhanced photo-production and degradation of diacids and related compounds. Throughout all seasons C3/C4 ratio at Gosan site, located

  4. Seasonal variation in human reproduction: environmental factors.

    Science.gov (United States)

    Bronson, F H

    1995-06-01

    Almost all human populations exhibit seasonal variation in births, owing mostly to seasonal variation in the frequency of conception. This review focuses on the degree to which environmental factors like nutrition, temperature and photoperiod contribute to these seasonal patterns by acting directly on the reproductive axis. The reproductive strategy of humans is basically that of the apes: Humans have the capacity to reproduce continuously, albeit slowly, unless inhibited by environmental influences. Two, and perhaps three, environmental factors probably act routinely as seasonal inhibitors in some human populations. First, it seems likely that ovulation is regulated seasonally in populations experiencing seasonal variation in food availability. More specifically, it seems likely that inadequate food intake or the increased energy expenditure required to obtain food, or both, can delay menarche, suppress the frequency of ovulation in the nonlactating adult, and prolong lactational amenorrhea in these populations on a seasonal basis. This action is most easily seen in tropical subsistence societies where food availability often varies greatly owing to seasonal variation in rainfall; hence births in these populations often correlate with rainfall. Second, it seems likely that seasonally high temperatures suppress spermatogenesis enough to influence the incidence of fertilization in hotter latitudes, but possibly only in males wearing clothing that diminishes scrotal cooling. Since most of our knowledge about this phenomenon comes from temperate latitudes, the sensitivity of spermatogenesis in both human and nonhuman primates to heat in the tropics needs further study. It is quite possible that high temperatures suppress ovulation and early embryo survival seasonally in some of these same populations. Since we know less than desired about the effect of heat stress on ovulation and early pregnancy in nonhuman mammals, and nothing at all about it in humans or any of the

  5. Seasonal variations of equatorial spread-F

    Directory of Open Access Journals (Sweden)

    B. V. Krishna Murthy

    Full Text Available The occurrence of spread-F at Trivandrum (8.5°N, 77°E, dip 0.5°N has been investigated on a seasonal basis in sunspot maximum and minimum years in terms of the growth rate of irregularities by the generalized collisional Rayleigh-Taylor (GRT instability mechanism which includes the gravitational and cross-field instability terms. The occurrence statistics of spread-F at Trivandrum have been obtained using quarter hourly ionograms. The nocturnal variations of the growth rate of irregularities by the GRT mechanism have been estimated for different seasons in sunspot maximum and minimum years at Trivandrum using h'F values and vertical drift velocities obtained from ionograms. It is found that the seasonal variation of spread-F occurrence at Trivandrum can, in general, be accounted for on the basis of the GRT mechanism.

  6. Seasonal variations of equatorial spread-F

    Directory of Open Access Journals (Sweden)

    K. S. V. Subbarao

    1994-01-01

    Full Text Available The occurrence of spread-F at Trivandrum (8.5°N, 77°E, dip 0.5°N has been investigated on a seasonal basis in sunspot maximum and minimum years in terms of the growth rate of irregularities by the generalized collisional Rayleigh-Taylor (GRT instability mechanism which includes the gravitational and cross-field instability terms. The occurrence statistics of spread-F at Trivandrum have been obtained using quarter hourly ionograms. The nocturnal variations of the growth rate of irregularities by the GRT mechanism have been estimated for different seasons in sunspot maximum and minimum years at Trivandrum using h'F values and vertical drift velocities obtained from ionograms. It is found that the seasonal variation of spread-F occurrence at Trivandrum can, in general, be accounted for on the basis of the GRT mechanism.

  7. Seasonal variations in the sources of natural and anthropogenic lead deposited at the East Rongbuk Glacier in the high-altitude Himalayas

    International Nuclear Information System (INIS)

    Burn-Nunes, Laurie; Vallelonga, Paul; Lee, Khanghyun; Hong, Sungmin; Burton, Graeme; Hou, Shugui; Moy, Andrew; Edwards, Ross; Loss, Robert; Rosman, Kevin

    2014-01-01

    Lead (Pb) isotopic compositions and concentrations, and barium (Ba) and indium (In) concentrations have been analysed at sub-annual resolution in three sections from a < 110 m ice core dated to the 18th and 20th centuries, as well as snow pit samples dated to 2004/2005, recovered from the East Rongbuk Glacier in the high-altitude Himalayas. Ice core sections indicate that atmospheric chemistry prior to ∼ 1953 was controlled by mineral dust inputs, with no discernible volcanic or anthropogenic contributions. Eighteenth century monsoon ice core chemistry is indicative of dominant contributions from local Himalayan sources; non-monsoon ice core chemistry is linked to contributions from local (Himalayan), regional (Indian/Thar Desert) and long-range (North Africa, Central Asia) sources. Twentieth century monsoon and non-monsoon ice core data demonstrate similar seasonal sources of mineral dust, however with a transition to less-radiogenic isotopic signatures that suggests local and regional climate/environmental change. The snow pit record demonstrates natural and anthropogenic contributions during both seasons, with increased anthropogenic influence during non-monsoon times. Monsoon anthropogenic inputs are most likely sourced to South/South-East Asia and/or India, whereas non-monsoon anthropogenic inputs are most likely sourced to India and Central Asia. - Highlights: • Pb isotopes in ice and snow show seasonality in Mt Everest atmospheric chemistry. • Local (Himalayan) mineral dust inputs are present year round. • Regional and long-range mineral dust inputs are evident during non-monsoon times. • Snow samples indicate increased anthropogenic inputs during non-monsoon times. • Anthropogenic inputs are linked with Indian, South Asian and Central Asian sources

  8. Seasonal variations in the sources of natural and anthropogenic lead deposited at the East Rongbuk Glacier in the high-altitude Himalayas

    Energy Technology Data Exchange (ETDEWEB)

    Burn-Nunes, Laurie, E-mail: L.Nunes@curtin.edu.au [Department of Imaging and Applied Physics, Curtin University, GPO Box U 1987, Perth 6845, Western Australia (Australia); Vallelonga, Paul [Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen Ø (Denmark); Lee, Khanghyun [Environmental Measurement and Analysis Center, National Institute of Environmental Research, Environmental Research Complex, Kyungseo-dong, Seo-gu, Incheon 404-170 (Korea, Republic of); Hong, Sungmin [Department of Ocean Sciences, Inha University, 100 Inha-ro, Nam-gu, Incheon 402-751 (Korea, Republic of); Burton, Graeme [Department of Imaging and Applied Physics, Curtin University, GPO Box U 1987, Perth 6845, Western Australia (Australia); Hou, Shugui [Key Laboratory of Coast and Island development of Ministry of Education, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210093 (China); Moy, Andrew [Department of the Environment, Australian Antarctic Division, Channel Highway, Kingston 7050, Tasmania (Australia); Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Private Bag 80, Hobart 7001, Tasmania (Australia); Edwards, Ross; Loss, Robert; Rosman, Kevin [Department of Imaging and Applied Physics, Curtin University, GPO Box U 1987, Perth 6845, Western Australia (Australia)

    2014-07-01

    Lead (Pb) isotopic compositions and concentrations, and barium (Ba) and indium (In) concentrations have been analysed at sub-annual resolution in three sections from a < 110 m ice core dated to the 18th and 20th centuries, as well as snow pit samples dated to 2004/2005, recovered from the East Rongbuk Glacier in the high-altitude Himalayas. Ice core sections indicate that atmospheric chemistry prior to ∼ 1953 was controlled by mineral dust inputs, with no discernible volcanic or anthropogenic contributions. Eighteenth century monsoon ice core chemistry is indicative of dominant contributions from local Himalayan sources; non-monsoon ice core chemistry is linked to contributions from local (Himalayan), regional (Indian/Thar Desert) and long-range (North Africa, Central Asia) sources. Twentieth century monsoon and non-monsoon ice core data demonstrate similar seasonal sources of mineral dust, however with a transition to less-radiogenic isotopic signatures that suggests local and regional climate/environmental change. The snow pit record demonstrates natural and anthropogenic contributions during both seasons, with increased anthropogenic influence during non-monsoon times. Monsoon anthropogenic inputs are most likely sourced to South/South-East Asia and/or India, whereas non-monsoon anthropogenic inputs are most likely sourced to India and Central Asia. - Highlights: • Pb isotopes in ice and snow show seasonality in Mt Everest atmospheric chemistry. • Local (Himalayan) mineral dust inputs are present year round. • Regional and long-range mineral dust inputs are evident during non-monsoon times. • Snow samples indicate increased anthropogenic inputs during non-monsoon times. • Anthropogenic inputs are linked with Indian, South Asian and Central Asian sources.

  9. Seasonal Variation of Cistus ladanifer L. Diterpenes

    Directory of Open Access Journals (Sweden)

    Juan Carlos Alías

    2012-07-01

    Full Text Available The exudate of Cistus ladanifer L. consists mainly of two families of secondary metabolites: flavonoids and diterpenes. The amount of flavonoids present in the leaves has a marked seasonal variation, being maximum in summer and minimum in winter. In the present study, we demonstrate that the amount of diterpenes varies seasonally, but with a different pattern: maximum concentration in winter and minimum in spring-summer. The experiments under controlled conditions have shown that temperature influences diterpene production, and in particular, low temperatures. Given this pattern, the functions that these compounds perform in C. ladanifer are probably different.

  10. Seasonal variation in food allergy to apple

    DEFF Research Database (Denmark)

    Skamstrup Hansen, K; Vieths, S; Vestergaard, H

    2001-01-01

    The aim of the study was to investigate the possibility of a seasonal variation in reactivity to apples in 27 birch pollen allergic patients. Before and during the birch pollen season 1998, the patients were subjected to double-blind, placebo-controlled food challenges (DBPCFCs) with grated fresh...... Golden Delicious apple followed by an open food challenge with whole fresh apple. The clinical reactions elicited during the challenges were evaluated both by the patients and the investigators. Moreover, the skin reactivity and the in vitro reactivity to apple were evaluated by skin prick test (SPT...

  11. Seasonal variations in the sources of natural and anthropogenic lead deposited at the East Rongbuk Glacier in the high-altitude Himalayas.

    Science.gov (United States)

    Burn-Nunes, Laurie; Vallelonga, Paul; Lee, Khanghyun; Hong, Sungmin; Burton, Graeme; Hou, Shugui; Moy, Andrew; Edwards, Ross; Loss, Robert; Rosman, Kevin

    2014-07-15

    Lead (Pb) isotopic compositions and concentrations, and barium (Ba) and indium (In) concentrations have been analysed at sub-annual resolution in three sections from a snow pit samples dated to 2004/2005, recovered from the East Rongbuk Glacier in the high-altitude Himalayas. Ice core sections indicate that atmospheric chemistry prior to ~1,953 was controlled by mineral dust inputs, with no discernible volcanic or anthropogenic contributions. Eighteenth century monsoon ice core chemistry is indicative of dominant contributions from local Himalayan sources; non-monsoon ice core chemistry is linked to contributions from local (Himalayan), regional (Indian/Thar Desert) and long-range (North Africa, Central Asia) sources. Twentieth century monsoon and non-monsoon ice core data demonstrate similar seasonal sources of mineral dust, however with a transition to less-radiogenic isotopic signatures that suggests local and regional climate/environmental change. The snow pit record demonstrates natural and anthropogenic contributions during both seasons, with increased anthropogenic influence during non-monsoon times. Monsoon anthropogenic inputs are most likely sourced to South/South-East Asia and/or India, whereas non-monsoon anthropogenic inputs are most likely sourced to India and Central Asia. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Seasonal variations of indoor radon concentrations

    International Nuclear Information System (INIS)

    Majborn, B.

    1990-01-01

    Seasonal variations of indoor radon concentrations have been studied in a cluster of 10 single-family houses. Eight of the houses are of a similar construction with slab-on-grade foundations. The remaining two houses have different substructures, one of them having a crawl space, and the other having partly a basement and partly a crawl space. A 'normal' seasonal variation of the radon concentration with a maximum in winter and a minimum in summer was observed in most of the houses. In these houses the variation showed a strong correlation with the indoor-outdoor temperature difference on a 2-month basis. However, deviating seasonal variations were observed in some of the houses, notably in the two houses having different substructures. This paper reports that a re-examination of the data obtained in a previous study indicates that winter/summer ratios of indoor radon concentrations in Danish houses depend on the house substructure. The mean winter/summer ratios were about 2.1 for houses with slab-on-grade foundations, 1.5 for houses having a basement, and 1.0 for houses with a crawl space (geometric mean values). However, a study with more houses in each substructure category will be needed to show whether or not the indicated differences are generally valid for Danish houses

  13. Oxidative potential of ambient PM2.5 in the coastal cities of the Bohai Sea, northern China: Seasonal variation and source apportionment.

    Science.gov (United States)

    Liu, WeiJian; Xu, YunSong; Liu, WenXin; Liu, QingYang; Yu, ShuangYu; Liu, Yang; Wang, Xin; Tao, Shu

    2018-05-01

    Emissions of air pollutants from primary and secondary sources in China are considerably higher than those in developed countries, and exposure to air pollution is main risk of public health. Identifying specific particulate matter (PM) compositions and sources are essential for policy makers to propose effective control measures for pollutant emissions. Ambient PM 2.5 samples covered a whole year were collected from three coastal cities of the Bohai Sea. Oxidative potential (OP) was selected as the indicator to characterize associated PM compositions and sources most responsible for adverse impacts on human health. Positive matrix factorization (PMF) and multiple linear regression (MLR) were employed to estimate correlations of PM 2.5 sources with OP. The volume- and mass-based dithiothreitol (DTT v and DTT m ) activities of PM 2.5 were significantly higher in local winter or autumn (p  0.700, p water-soluble organic carbon (WSOC) and some transition metals. Using PMF, source fractions of PM 2.5 were resolved as secondary source, traffic source, biomass burning, sea spray and urban dust, industry, coal combustion, and mineral dust. Further quantified by MLR, coal combustion, biomass burning, secondary sources, industry, and traffic source were dominant contributors to the water-soluble DTT v activity. Our results also suggested large differences in seasonal contributions of different sources to DTT v variability. A higher contribution of DTT v was derived from coal combustion during the local heating period. Secondary sources exhibited a greater fraction of DTT v in summer, when there was stronger solar radiation. Traffic sources exhibited a prevailing contribution in summer, and industry contributed larger proportions in spring and winter. Future abatement priority of air pollution should reduce the sources contributing to OP of PM 2.5 . Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Seasonal variations and sources of ambient fossil and biogenic-derived carbonaceous aerosols based on 14C measurements in Lhasa, Tibet

    Science.gov (United States)

    Huang, Jie; Kang, Shichang; Shen, Chengde; Cong, Zhiyuan; Liu, Kexin; Wang, Wei; Liu, Lichao

    2010-06-01

    A total of 30 samples of total suspended particles were collected at an urban site in Lhasa, Tibet from August 2006 to July 2007 for investigating carbonaceous aerosol features. The fractions of contemporary carbon ( fc) in total carbon (TC) of ambient aerosols are presented using radiocarbon ( 14C) measurements. The value of fc represents the biogenic contribution to TC, as the biosphere releases organic compounds with the present 14C/ 12C level ( fc = 1), whereas 14C has become extinct in anthropogenic emissions of fossil carbon ( fc = 0). The fc values in Lhasa ranging from 0.357 to 0.702, are higher than Beijing and Tokyo, but clearly lower than the rural region of Launceston, which indicates a major biogenic influence in Lhasa. Seasonal variations of fc values corresponded well with variations of pollutants concentrations (e.g. NO 2). Higher fc values appeared in winter indicating carbonaceous aerosol is more dominated by wood burning and incineration of agricultural wastes within this season. The lower fc values in summer and autumn may be caused by increased diesel and petroleum emissions related to tourism in Lhasa. δ13C values ranged from - 26.40‰ to - 25.10‰, with relative higher values in spring and summer, reflecting the increment of fossil carbon emissions.

  15. Seasonal variation in male alternative reproductive tactics.

    Science.gov (United States)

    Monroe, M J; Amundsen, T; Utne-Palm, A C; Mobley, K B

    2016-12-01

    Genetic parentage analyses reveal considerable diversity in alternative reproductive behaviours (e.g. sneaking) in many taxa. However, little is known about whether these behaviours vary seasonally and between populations. Here, we investigate seasonal variation in male reproductive behaviours in a population of two-spotted gobies (Gobiusculus flavescens) in Norway. Male two-spotted gobies guard nests, attract females and care for fertilized eggs. We collected clutches and nest-guarding males early and late in the breeding season in artificial nests and used microsatellite markers to reconstruct parentage from a subset of offspring from each nest. We hypothesized that mating, reproductive success and sneaking should be more prevalent early in the breeding season when competition for mates among males is predicted to be higher. However, parentage analyses revealed similar values of mating, reproductive success and high frequencies of successful sneaking early (30% of nests) and late (27% of nests) in the season. We also found that multiple females with eggs in the same nest were fertilized by one or more sneaker males, indicating that some males in this population engage in a satellite strategy. We contrast our results to previous work that demonstrates low levels of cuckoldry in a population in Sweden. Our results demonstrate marked stability in both the genetic mating system and male alternative reproductive tactics over the breeding season. However, sneaking rates may vary geographically within a species, likely due to local selection influencing ecological factors encountered at different locations. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

  16. Seasonal variation in admission for heart failure, hypertension and ...

    African Journals Online (AJOL)

    Seasonal variation in admission for heart failure, hypertension and stroke. ... Background: Seasonal variation in hospitalization for cardiovascular disease has been ... hypertension and hypertension – related stroke (Cerebrovascular accident) ...

  17. Seasonal variations of volcanic eruption frequencies

    Science.gov (United States)

    Stothers, Richard B.

    1989-01-01

    Do volcanic eruptions have a tendency to occur more frequently in the months of May and June? Some past evidence suggests that they do. The present study, based on the new eruption catalog of Simkin et al.(1981), investigates the monthly statistics of the largest eruptions, grouped according to explosive magnitude, geographical latitude, and year. At the 2-delta level, no month-to-month variations in eruption frequency are found to be statistically significant. Examination of previously published month-to-month variations suggests that they, too, are not statistically significant. It is concluded that volcanism, at least averaged over large portions of the globe, is probably not periodic on a seasonal or annual time scale.

  18. Seasonal Variations of High Time-Resolved Chemical Compositions, Sources and Evolution for Atmospheric Submicron Aerosols in the Megacity of Beijing

    Science.gov (United States)

    Hu, Min; Hu, Wei; Hu, Weiwei; Zheng, Jing; Guo, Song; Wu, Yusheng; Lu, Sihua; Zeng, Limin

    2016-04-01

    This study aims to investigate aerosol secondary formation and aging process in the megacity of Beijing. Seasonal intensive campaigns were conducted from March 2012 to March 2013 at an urban site located at the campus of Peking University (116.31° E, 37.99° N). An Aerodyne high-resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS) and other relevant instrumentations for gaseous and particulate pollutants were deployed. The average submicron aerosol (PM1) mass concentrations were 45.1 ± 45.8, 37.5 ± 31.0, 41.3 ± 42.7 and 81.7 ± 72.4 μg m-3 in spring, summer, autumn and winter, respectively. Organic matter was the most abundant component, accounting for 31%, 33%, 44% and 36% in PM1 correspondingly, followed by sulfate and nitrate. Distinct seasonal and diurnal patterns of the components of PM1 tracking primary sources (e.g., BC and HOA) and secondary formation (e.g., sulfate, nitrate, ammonium, LV-OOA and SV-OOA) were significantly influenced by primary emissions and mesoscale meteorology. Combining positive matrix factorization (PMF) analysis with the mass spectrometry of organics measured by AMS, the contributions of primary and secondary sources to submicron organic aerosols (OA) were apportioned. In spring and summer, the primary sources were hydrocarbon-like OA (HOA) and cooking OA (COA), and the secondary components were low volatility (LV-OOA) and semi-volatile oxygenated OA (SV-OOA). In winter biomass burning OA (BBOA) was also resolved. In autumn, four factors were resolved, that is, OOA, HOA, COA and BBOA. In general, OOA (sum of LV-OOA and SV-OOA) was important in OA in four seasons, accounting for about 63%, 70%, 47% and 50%, respectively. SV-OOA dominated OA in summer (44%) due to the fresh secondary formation from strong photochemical oxidations; whereas, LV-OOA was dominant in OA in winter (33%), maybe because the transported air masses were more aged in heavily polluted days. The POA (sum of HOA, COA and BBOA) in OA was dominant in

  19. Seasonal variation, risk assessment and source estimation of PM 10 and PM10-bound PAHs in the ambient air of Chiang Mai and Lamphun, Thailand.

    Science.gov (United States)

    Pengchai, Petch; Chantara, Somporn; Sopajaree, Khajornsak; Wangkarn, Sunanta; Tengcharoenkul, Urai; Rayanakorn, Mongkon

    2009-07-01

    /APCS) model and multiple regression analysis were applied to the PM10 and its constituents data. The results pointed to the vegetative burning as the largest PM10 contributor in Chiang Mai and Lamphun ambient air. Vegetative burning, natural gas burning & coke ovens, and secondary particle accounted for 46-82%, 12-49%, and 3-19% of the PM10 concentrations, respectively. However, natural gas burning & coke ovens as well as vehicle exhaust also deserved careful attention due to their large contributions to PAHs concentration. In the wet season and transition periods, 42-60% of the total PAHs concentrations originated from vehicle exhaust while 16-37% and 14-38% of them were apportioned to natural gas burning & coke ovens and vegetative burning, respectively. In the dry period, natural gas burning & coke ovens, vehicle exhaust, and vegetative burning accounted for 47-59%, 20-25%, and 19-28% of total PAHs concentrations. The close agreement between the measured and predicted concentrations data (R(2) > 0.8) assured enough capability of PCA/APCS receptor model to be used for the PM10 and PAHs source apportionment.

  20. Seasonal Variation in Group Size Is Related to Seasonal Variation in Neuropeptide Receptor Density.

    Science.gov (United States)

    Wilson, Leah C; Goodson, James L; Kingsbury, Marcy A

    2016-01-01

    In many species, seasonal variation in grouping behavior is widespread, with shifts towards territoriality in the breeding season and grouping in the winter. Compared to the hormonal and neural mechanisms of seasonal territorial aggression, the mechanisms that promote seasonal grouping have received little attention. We collected brains in spring and winter from wild-caught males of two species of emberizid sparrows that seasonally flock (the field sparrow, Spizella pusilla, and the dark-eyed junco, Junco hyemalis) and two species that do not seasonally flock (the song sparrow, Melospiza melodia, and the eastern towhee, Pipilo erythrophthalmus). We used receptor autoradiography to quantify seasonal plasticity in available binding sites for three neuropeptides known to influence social behavior. We examined binding sites for 125I-vasoactive intestinal polypeptide (VIP), 125I-sauvagine (SG, a ligand for corticotropin-releasing hormone receptors) and 125I-ornithine vasotocin analog (OVTA, a ligand for the VT3 nonapeptide). For all species and ligands, brain areas that exhibited a seasonal pattern in binding density were characterized by a winter increase. Compared to nonflocking species, seasonally flocking species showed different binding patterns in multiple brain areas. Furthermore, we found that winter flocking was associated with elevated winter 125I-VIP binding density in the medial amygdala, as well as 125I-VIP and 125I-OVTA binding density in the rostral arcopallium. While the functional significance of the avian rostral arcopallium is unclear, it may incorporate parts of the pallial amygdala. Our results point to this previously undescribed area as a likely hot spot of social modulation. © 2016 S. Karger AG, Basel.

  1. Seasonal variation in heavy metal concentration in mangrove foliage

    Digital Repository Service at National Institute of Oceanography (India)

    Untawale, A.G.; Wafar, S.; Bhosle, N.B.

    Seasonal variation in the concentration of some heavy metals in the leaves of seven species of mangrove vegetation from Goa, revealed that maximum concentration of iron and manganese occurs during the monsoon season without any significant toxic...

  2. Seasonal variation in the Dutch bovine raw milk composition

    NARCIS (Netherlands)

    Heck, J.M.L.; Valenberg, van H.J.F.; Dijkstra, J.; Hooijdonk, van A.C.M.

    2009-01-01

    In this study, we determined the detailed composition of and seasonal variation in Dutch dairy milk. Raw milk samples representative of the complete Dutch milk supply were collected weekly from February 2005 until February 2006. Large seasonal variation exists in the concentrations of the main

  3. Seasonal variation of radon concentrations in UK homes

    International Nuclear Information System (INIS)

    Miles, J C H; Howarth, C B; Hunter, N

    2012-01-01

    The patterns of seasonal variation of radon concentrations were measured in 91 homes in five regions of the UK over a period of two years. The results showed that there was no significant difference between the regions in the pattern or magnitude of seasonal variation in radon concentrations. The arithmetic mean variation was found to be close to that found previously in the UK national survey. Differences in the pattern between the two years of the study were not significant. Two-thirds of homes in the study followed the expected pattern of high radon in the winter and low radon in the summer. Most of the rest showed little seasonal variation, and a few showed a reversed seasonal pattern. The study does not provide any clear evidence for the recorded house characteristics having an effect on the seasonal variation in radon concentrations in UK homes, though the statistical power for determining such effects is limited in this study. The magnitude of the seasonal variation varied widely between homes. Analysis of the individual results from the homes showed that because of the wide variation in the amount of seasonal variation, applying seasonal correction factors to the results of three-month measurements can yield only relatively small improvements in the accuracy of estimates of annual mean concentrations.

  4. Variation in water potential, hydraulic characteristics and water source use in montane Douglas-fir and lodgepole pine trees in southwestern Alberta and consequences for seasonal changes in photosynthetic capacity.

    Science.gov (United States)

    Andrews, Shilo F; Flanagan, Lawrence B; Sharp, Eric J; Cai, Tiebo

    2012-02-01

    Tree species response to climate change-induced shifts in the hydrological cycle depends on many physiological traits, particularly variation in water relations characteristics. We evaluated differences in shoot water potential, vulnerability of branches to reductions in hydraulic conductivity, and water source use between Pinus contorta Dougl. ex Loud. var. latifolia Engelm. (lodgepole pine) and Pseudotsuga menziesii (Mirb.) Franco (interior Douglas-fir), and determined the consequences for seasonal changes in photosynthetic capacity. The Douglas-fir site had soil with greater depth, finer texture and higher organic matter content than soil at the lodgepole pine site, all factors that increased the storage of soil moisture. While the measured xylem vulnerability curves were quite similar for the two species, Douglas-fir had lower average midday shoot water potentials than did lodgepole pine. This implied that lodgepole pine exhibited stronger stomatal control of transpiration than Douglas-fir, which helped to reduce the magnitude of the water potential gradient required to access water from drying soil. Stable hydrogen isotope measurements indicated that Douglas-fir increased the use of groundwater during mid-summer when precipitation inputs were low, while lodgepole pine did not. There was a greater reduction of photosynthetic carbon gain in lodgepole pine compared with Douglas-fir when the two tree species were exposed to seasonal declines in soil water content. The contrasting patterns of seasonal variation in photosynthetic capacity observed for the two species were a combined result of differences in soil characteristics at the separate sites and the inherent physiological differences between the species.

  5. 489 SEASONAL VARIATION IN PHYSICO-CHEMICAL ...

    African Journals Online (AJOL)

    Osondu

    higher concentration during the wet season than in the dry season in all the Groups, except for BOD, sulphate and iron. ... availability and quality of groundwater due to waste and ... using 1 litre plastic containers that were treated with 3-4ml of ...

  6. Seasonal variations in hospital admissions for mania

    DEFF Research Database (Denmark)

    Medici, Clara Reece; Vestergaard, Claus Høstrup; Hadzi-Pavlovic, Dusan

    2016-01-01

    in summer. Higher admission rates were associated with more sunshine, more ultraviolet radiation, higher temperature and less snow but were unassociated with rainfall. We did not find a secular trend in the seasonal pattern. Finally, neither gender nor admission status impacted on the overall seasonal...

  7. Seasonal variation, spatial distribution and source apportionment for polycyclic aromatic hydrocarbons (PAHs) at nineteen communities in Xi'an, China: The effects of suburban scattered emissions in winter

    International Nuclear Information System (INIS)

    Wang, Jingzhi; Cao, Junji; Dong, Zhibao; Guinot, Benjamin; Gao, Meiling; Huang, Rujin; Han, Yongming; Huang, Yu

    2017-01-01

    Seasonal variation and spatial distribution of PM 2.5 bound polycyclic aromatic hydrocarbons (PAHs) were investigated at urban residential, commercial area, university, suburban region, and industry in Xi'an, during summer and winter time at 2013. Much higher levels of total PAHs were obtained in winter. Spatial distributions by kriging interpolations principle showed that relative high PAHs were detected in western Xi'an in both summer and winter, with decreasing trends in winter from the old city wall to the 2 nd -3rd ring road except for the suburban region and industry. Coefficients of diversity and statistics by SPSS method demonstrated that PAHs in suburban have significant differences (t < 0.05) with those in urban residential in both seasons. The positive Matrix Factorization (PMF) modeling indicated that biomass burning (31.1%) and vehicle emissions (35.9%) were main sources for PAHs in winter and summer in urban, which different with the suburban. The coal combustion was the main source for PAHs in suburban region, which accounted for 46.6% in winter and sharp decreased to 19.2% in summer. Scattered emissions from uncontrolled coal combustion represent an important source of PAHs in suburban in winter and there were about 135 persons in Xi'an will suffer from lung cancer for lifetime exposure at winter levels. Further studies are needed to specify the effluence of the scattered emission in suburban to the city and to develop a strategy for controlling those emissions and lighten possible health effects. - Highlights: • PM 2.5 bound PAHs were investigated in nineteen communities of Xi'an at 2013. • High amount of uncontrolled coal combustion were happened in suburban at winter. • About 135 persons in Xi'an will suffer from lung cancer for exposure at winter. - The high contribution of coal combustion for PAHs in suburban region demonstrated the high amount of scattered emissions in winter.

  8. Aerosol characterization over the southeastern United States using high-resolution aerosol mass spectrometry: spatial and seasonal variation of aerosol composition and sources with a focus on organic nitrates

    Science.gov (United States)

    Xu, L.; Suresh, S.; Guo, H.; Weber, R. J.; Ng, N. L.

    2015-07-01

    We deployed a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and an Aerosol Chemical Speciation Monitor (ACSM) to characterize the chemical composition of submicron non-refractory particulate matter (NR-PM1) in the southeastern USA. Measurements were performed in both rural and urban sites in the greater Atlanta area, Georgia (GA), and Centreville, Alabama (AL), for approximately 1 year as part of Southeastern Center for Air Pollution and Epidemiology study (SCAPE) and Southern Oxidant and Aerosol Study (SOAS). Organic aerosol (OA) accounts for more than half of NR-PM1 mass concentration regardless of sampling sites and seasons. Positive matrix factorization (PMF) analysis of HR-ToF-AMS measurements identified various OA sources, depending on location and season. Hydrocarbon-like OA (HOA) and cooking OA (COA) have important, but not dominant, contributions to total OA in urban sites (i.e., 21-38 % of total OA depending on site and season). Biomass burning OA (BBOA) concentration shows a distinct seasonal variation with a larger enhancement in winter than summer. We find a good correlation between BBOA and brown carbon, indicating biomass burning is an important source for brown carbon, although an additional, unidentified brown carbon source is likely present at the rural Yorkville site. Isoprene-derived OA factor (isoprene-OA) is only deconvolved in warmer months and contributes 18-36 % of total OA. The presence of isoprene-OA factor in urban sites is more likely from local production in the presence of NOx than transport from rural sites. More-oxidized and less-oxidized oxygenated organic aerosol (MO-OOA and LO-OOA, respectively) are dominant fractions (47-79 %) of OA in all sites. MO-OOA correlates well with ozone in summer but not in winter, indicating MO-OOA sources may vary with seasons. LO-OOA, which reaches a daily maximum at night, correlates better with estimated nitrate functionality from organic nitrates than total nitrates. Based

  9. Appendicitis: Trends in incidence, age, sex, and seasonal variations ...

    African Journals Online (AJOL)

    Background:Appendicitis is a common clinical condition worldwide. Differences in ... Aim:To assess the trends in incidence and pattern of variation with age, sex, and seasons of the year. .... population of 465000 (an annual population growth.

  10. Seasonal variations in the microflora from mangrove swamps in Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Matondkar, S.G.P.; Mathani, S.; Mavinkurve, S.

    Seasonal variations in bacterial and fungal counts from the water and sediment samples of mangrove ecosystem of Goa (India) show that this ecosystem supports a very high population of fungi and bacteria...

  11. Seasonal Variations of Some Physico-Chemical Properties of River ...

    African Journals Online (AJOL)

    MICHAEL

    The sampling points represent the villages within Abraka clan along the river. The seasonal variations are ... untreated waste water or poorly treated effluents accrued from .... Fakayode, S.O. (2005): Impact Assessment of. Industrial Effluent on ...

  12. Seasonal and daily variation in blood and urine concentrations of ...

    African Journals Online (AJOL)

    1998-03-17

    Mar 17, 1998 ... ... both seasonal and daily cyclic variation in water stress, with concomitant changes in ... nutritional) stress, are of dubious applicability to animals in their natural ..... The similarity of haematocrit measurements in the two sea-.

  13. Assessment and Seasonal Variations of Heavy Metals and Mineral ...

    African Journals Online (AJOL)

    Mal Raji

    ISSN 0794-5698. Assessment and Seasonal Variations of Heavy Metals and Mineral Elements in River ... immediately from Sokoto Cement Factory) at value above WHO's permissible limit in the rainy season. Ag .... level which is considered to represent a threat to the life of .... regulations governing waste management and.

  14. Seasonal variations in heavy metal concentrations in soil and some ...

    African Journals Online (AJOL)

    In this study, the seasonal variations in concentrations of the heavy metals - As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn - in soil and crops from a farm near the refuse dump site of Obafemi Awolowo University, Ile-Ife, Nigeria were investigated during the two major seasons of Nigeria. This was done to assess the pollution ...

  15. Seasonal Variation in Trypanosomosis Rates in Small Ruminants at ...

    African Journals Online (AJOL)

    Seasonal variation in trypanosome parasitological infection rates in small ruminants was studied at the Kaduna Central abattoir, North Central Nigeria. Blood samples were obtained at slaughter from 320 goats and 209 sheep during the dry and rainy seasons and examined using the Haematocrit Centrifugation Technique ...

  16. Seasonal variation of air kerma in the 'Vulcano Porto' area (Aeolian Islands, Italy)

    International Nuclear Information System (INIS)

    Bellia, S.; Basile, S.; Brai, M.; Hauser, S.; Puccio, P.; Rizzo, S.

    2001-01-01

    Air kerma was measured in the 'Vulcano Porto' area of the Vulcano Island, belonging to the Aeolian Islands, in the Mediterranean Sea. Measurements were carried out using thermoluminescence dosimeters. The relationship between observed dose values and source lithology has been assessed. Data show a seasonal variation due to weather conditions but also probably related to features of the soils, making the variation more evident

  17. Seasonal variation of air kerma in the "Vulcano Porto" area (Aeolian Islands, Italy).

    Science.gov (United States)

    Bellia, S; Basile, S; Brai, M; Hauser, S; Puccio, P; Rizzo, S

    2001-04-01

    Air kerma was measured in the "Vulcano Porto" area of the Vulcano Island, belonging to the Aeolian Islands, in the Mediterranean Sea. Measurements were carried out using thermoluminescence dosimeters. The relationship between observed dose values and source lithology has been assessed. Data show a seasonal variation due to weather conditions but also probably related to features of the soils, making the variation more evident.

  18. Cost of heat from a seasonal source

    Science.gov (United States)

    Reilly, R. W.; Brown, D. R.; Huber, H. D.

    Results are reported of an investigation to estimate the cost of aquifer thermal energy storage (ATES) from a seasonal heat source. The cost of supplying energy (hot water) from an ATES system is estimated. Three types of loads are investigated: point demands, residential developments, and a multidistrict city. Several technical and economic factors are found to control the economic performance of an ATES system. Costs are found to be prohibitive for systems of small size, long transmission distances, and employing expensive purchased thermal energy. ATES is found to be cost-competitive with oil-fired and electric hot water delivery systems under a broad range of potential situations.

  19. Seasonal variation and predictors of epistaxis.

    Science.gov (United States)

    Purkey, Matthew R; Seeskin, Zachary; Chandra, Rakesh

    2014-09-01

    To examine the incidence of epistaxis as a function of season and age and to determine predictors of episodes within the epistaxis patient population presenting to a tertiary hospital system. Retrospective cohort study. Electronic medical record charts of patients presenting to the Northwestern Emergency Department, admitted to an inpatient ward, or seen in an outpatient setting between 2008 and 2012 were reviewed and selected for an International Classifications of Disease-Ninth Revision epistaxis code of 784.7. Season of presentation, demographic factors (age, race, gender, insurance status), medication use (including anticoagulants and topical nasal steroid administration), and several comorbidities were analyzed as potential predictors of episodes. A total of 2,405 patients were identified with a total of 3,666 individual epistaxis episodes over 5 years. Multivariate analysis identified allergic rhinitis (AR), chronic sinusitis (CRS), coagulopathy, hereditary hemorrhagic telangiectasia (HHT), hematologic malignancy, and hypertension (HTN) as predictors of a higher number of cases. Epistaxis occurred more frequently during colder months and in older patients. Epistaxis occurs more commonly during the winter and in older patients. AR, CRS, coagulopathy, HHT, hematologic malignancy, and HTN are associated with increased epistaxis incidence. © 2014 The American Laryngological, Rhinological and Otological Society, Inc.

  20. Seasonal variation of heat consumption in greenhouses

    DEFF Research Database (Denmark)

    Nielsen, O.F.; Amsen, M.G.; Strøm, J.S.

    The concept of dynamic variation is introduced as a method to visualize the dynamic fluctuations of heat consumption and thermal climate in greenhouses. The feasibility of the concept is illustrated by describing effects of different greenhouse designs. Engineering data on design heat consumption...

  1. Seasonal variation of dystocia in a large Danish cohort.

    Science.gov (United States)

    Rohr Thomsen, Christine; Uldbjerg, Niels; Hvidman, Lone; Atladóttir, Hjördís Ósk; Henriksen, Tine Brink; Milidou, Ioanna

    2014-01-01

    Dystocia is one of the most frequent causes of cesarean delivery in nulliparous women. Despite this, its causes are largely unknown. Vitamin D receptor (VDR) has been found in the myometrium. Thus, it is possible that vitamin D affects the contractility of the myometrium and may be involved in the pathogenesis of dystocia. Seasonal variation of dystocia in areas with distinct seasonal variation in sunlight exposure, like Denmark, could imply that vitamin D may play a role. This study examined whether there was seasonal variation in the incidence of dystocia in a Danish population. We used information from a cohort of 34,261 nulliparous women with singleton pregnancies, spontaneous onset of labor between 37 and 42 completed gestational weeks, and vertex fetal presentation. All women gave birth between 1992 and 2010 at the Department of Obstetrics and Gynecology, Aarhus University Hospital, Skejby. Logistic regression combined with cubic spline was used to estimate the seasonal variation for each outcome after adjusting for calendar time. No evidence for seasonal variation was found for any of the outcomes: acute cesarean delivery due to dystocia (p = 0.44); instrumental vaginal delivery due to dystocia (p = 0.69); oxytocin augmentation due to dystocia (p = 0.46); and overall dystocia (p = 0.91). No seasonal variation in the incidence of dystocia was observed in a large cohort of Danish women. This may reflect no association between vitamin D and dystocia, or alternatively that other factors with seasonal variation and influence on the occurrence of dystocia attenuate such an association.

  2. Seasonal Variation in Human Salivary Cortisol Concentration

    DEFF Research Database (Denmark)

    Persson, Roger; Garde, Anne Helene; Hansen, Åse Marie

    2008-01-01

    Measurement of cortisol concentration can contribute important information about an individual's ability to adjust to various environmental demands of both physical and psychosocial origin. However, one uncertainty that affects the possibilities of correctly interpreting and designing field studies...... is the lack of observations of the impact of seasonal changes on cortisol excretion. For this reason, the month-to-month changes in diurnal cortisol concentration, the awakening cortisol response (ACR), maximum morning concentration, and fall during the day were studied in a group of 24 healthy men and women...... 32 to 61 yrs of age engaged in active work. On one workday for 12 consecutive months, participants collected saliva at four time points for determination of cortisol: at awakening, +30 min, +8 h, and at 21:00 h. Data were analyzed by a repeated measures design with month (12 levels) and time...

  3. Seasonal variation in the prevalence of preeclampsia

    Directory of Open Access Journals (Sweden)

    Fatemeh Janani

    2017-01-01

    Full Text Available Introduction: Hypertension in pregnancy is one of the three factors of maternal mortality. Etiology of the disease is unknown, but the many factors contributing to the identification and control of it can be taken a step to prevent and reduce the symptoms of the disease. The purpose of this study was to determine the prevalence of preeclampsia (high-blood pressure in different seasons of the year. Methods: The present retrospective cross-sectional study was conducted on more than 8,000 pregnant women visiting Assali specialized hospital from 2011 to 2013. Required data was collected through questionnaire checklist. The Chi-square test with multiple comparisons was used to compare the frequencies of pregnancy-induced hypertension (PIH according to the month of year, and adjustment of multiplicity was conducted using Bonferroni's method. Student's t-test was used to compare the means of PIH prevalence rates. In all analyses, P < 0.05 was taken to indicate statistical significance. Results: In these 8000 woman admitted to labor, overall prevalence of PIH was 3.8 ± 0.6%. The prevalence rate of PIH was highest in the summer (4.5% and lowest frequent in the winter (2.7%, respectively. In July, the prevalence rate was significantly higher than those for any other month (4.7%, and in March, it was lower prevalence than for any month (2.2%, respectively. Using the Chi-square test, a significant difference between the incidence of disease was observed in summer and winter (P < 0.001. Conclusion: The prevalence rate of PIH was higher for delivery in summer and early spring and lowest for winter delivery among Khorramabad women based on these results; it seems that changes in temperature and humidity in different seasons can affect preeclampsia, and preeclampsia increases with increasing frequency temperature.

  4. Seasonal variation and food deprivation in common vampire bats (Chiroptera: Phyllostomidae

    Directory of Open Access Journals (Sweden)

    M. B. Freitas

    Full Text Available The aim of this study was to investigate the effects of seasonal variation and fasting on fat reserves of the common vampire bat Desmodus rotundus. Plasma free fatty acids (FFA, along with lipid content of the liver and muscles, and fatty acids from the carcass were obtained from bats fed bovine blood and from whom food was subsequently withheld for 24 and 48 h. Animals were caught during both dry and rainy seasons. In general, fat tissue stores were not significantly influenced by seasonal variation. Lipid content of liver, muscles, and carcass decreased during some food deprivation periods, although the concomitant increase expected in plasma FFA was not observed. Lipid metabolism is hypothesized as being continued by the tissues themselves. In addition, free access to food sources (e.g., domestic livestock throughout the year is believed to contribute to the low seasonal variations in fat reserves observed in the common vampire bat.

  5. Seasonal variation of flavonoids in Teucrium polium L. (Lamiaceae

    Directory of Open Access Journals (Sweden)

    Gjoshe Stefkov

    2009-02-01

    Full Text Available Тhe aim of the present study was identification of flavone aglycones and determination of the content of each and the content of total flavonoids as well as investigation of the eventual seasonal variations of flavonoids in Teucrium polium L. (Lamiaceae. The plant samples were collected at six different locations in Republic of Macedonia, during summer in 1999, 2000 and 2003. For determination of seasonal variations, the samples were collected in v. Koleshino, in 2004, each month during the whole season. Six flavone aglycones (luteolin, apigenin, diosmetin, cirsiliol, cirsimaritin and cirsilineol were identified in the hydrolyzed extracts of the over ground part of Teucrium polium by HPLC method. The most abundant flavone was luteolin, followed by apigenin and cirsimaritin. Great seasonal variations were found in the content of each and in the content of total amount of flavonoids. The most abundant flavone during the whole season was luteolin with the highest content in May. The content of total flavonids was the highest in the period from May to July, which could be recommended as the most convenience period in the season for collecting of the plant material from Teucrium polium.

  6. Secular trends in seasonal variation in birth weight

    DEFF Research Database (Denmark)

    Jensen, Camilla Bjørn; Gamborg, M; Raymond, K

    2015-01-01

    and phase of the yearly cycles to change. RESULTS: There was a clear seasonal pattern in BW which, however, changed gradually across the study period. The highest BWs were seen during fall (September - October) from 1936 to 1963, but a new peak gradually grew from the early 1940s during early summer (May...... again. Sunshine did not explain the seasonal variation in BW. CONCLUSION: There was a clear seasonal pattern in BW in Denmark 1936-1989, which however changed across the study period. Throughout the study period we observed a peak in BW during the fall, but gradually, starting in the early 1940s...

  7. Seasonal variations of antioxidants in the brown seaweed Saccharina latissima

    DEFF Research Database (Denmark)

    Sørensen, Ann-Dorit Moltke; Safafar, Hamed; Pedersen, Anja

    Mainly the brown seaweeds are known for their high antioxidative capacity within the specific compounds such as phlorotannins, polyphenols, flavonoids, pigments, and these natural antioxidants are of high industrial interest. Previous studies have shown large seasonal variations in biomass...... composition. The aim of this study was to see if there was a seasonal variation in the antioxidant content of sugar kelp (Saccharina latissima), compare two cultivation sites, REF and IMTA, and test different solvents applied for extractions, methanol or ethyl acetate. Rope cultivated sugar kelp were sampled...

  8. Seasonal variation in the Dutch bovine raw milk composition.

    Science.gov (United States)

    Heck, J M L; van Valenberg, H J F; Dijkstra, J; van Hooijdonk, A C M

    2009-10-01

    In this study, we determined the detailed composition of and seasonal variation in Dutch dairy milk. Raw milk samples representative of the complete Dutch milk supply were collected weekly from February 2005 until February 2006. Large seasonal variation exists in the concentrations of the main components and milk fatty acid composition. Milk lactose concentration was rather constant throughout the season. Milk true protein content was somewhat more responsive to season, with the lowest content in June (3.21 g/100 g) and the highest content in December (3.38 g/100 g). Milk fat concentration increased from a minimum of 4.10 g/100 g in June to a maximum of 4.57 g/100 g in January. The largest (up to 2-fold) seasonal changes in the fatty acid composition were found for trans fatty acids, including conjugated linoleic acid. Milk protein composition was rather constant throughout the season. Milk unsaturation indices, which were used as an indication of desaturase activity, were lowest in spring and highest in autumn. Compared with a previous investigation of Dutch dairy milk in 1992, the fatty acid composition of Dutch raw milk has changed considerably, in particular with a higher content of saturated fatty acids in 2005 milk.

  9. seasonal variation and prevalence of tuberculosis among health

    African Journals Online (AJOL)

    Damary

    2006-11-11

    Nov 11, 2006 ... effects of seasonal variation on the incidence of TB in the study area and to use sentinel analysis to predict areas of ... One third of the world's population is exposed to TB ... residence and ethnic origin) were collected from all.

  10. Seasonal variations in aerosol optical properties over China

    Science.gov (United States)

    Yuesi Wang; Jinyuan Xin; Zhanqing Li; Shigong Wang; Pucai Wang; Wei Min Hao; Bryce L. Nordgren; Hongbin Chen; Lili Wang; Yang Sun

    2012-01-01

    Seasonal variations in background aerosol optical depth (AOD) and aerosol type are investigated over various ecosystems in China based upon three years' worth of meteorological data and data collected by the Chinese Sun Hazemeter Network. In most parts of China, AODs are at a maximum in spring or summer and at a minimum in autumn or winter. Minimum values (0.10~0....

  11. Role of women in food security and seasonal variation of ...

    African Journals Online (AJOL)

    This study examined the socio-economic characteristics, role of women and expenditure pattern as it relates to seasonal variation in lagoon and marine fishing communities in Lagos State. A two stage stratified sampling method was used to select the sample size of 210 fishing (35 female and 175 male–headed) ...

  12. Seasonal variation of the South Indian tropical gyre

    NARCIS (Netherlands)

    Aguiar-González, B.; Ponsoni, Leandro; Ridderinkhof, H.; van Aken, H.M.; de Ruijter, W.P.M.; Maas, L.R.M.

    2016-01-01

    Based on satellite altimeter data and global atlases of temperature, salinity, wind stress and wind-driven circulation we investigate the seasonal variation of the South Indian tropical gyre and its associated open-ocean upwelling system, known as the Seychelles–Chagos Thermocline Ridge (SCTR).

  13. Effects of seasonal variation and tidal regimes on macrobenthic ...

    African Journals Online (AJOL)

    An assessment of the effects of seasonal variation and tidal regimes on the distribution and density of macrobenthic invertebrates of the coastal Warri River, southern Nigeria was carried out from July 2014 to February 2015. Samples were collected from five longitudinal stations from headwater to mouth during high and low ...

  14. Seasonal variation in semen quality of Dorper rams using different ...

    African Journals Online (AJOL)

    Seasonal variation in semen quality of Dorper rams using different collection ... libitum throughout the trial, and all rams being fed a 2.5 kg maintenance diet per day. ... quality collected by the AV versus the EE collection method was recorded.

  15. Seasonal variations of physico-chemical properties of the Great ...

    African Journals Online (AJOL)

    The present study was attempted on the physico-chemical variability of the Great Vedaranyam Swamp of the Point Calimere Wildlife Sanctuary, South-east coast of India. Seasonal variation study was carried out to examine level of varying physico-chemical parameters such as temperature, salinity, pH, dissolved oxygen, ...

  16. Influence of flood variation on seasonal floodplain vegetation ...

    African Journals Online (AJOL)

    This study investigated the influence of flooding variation on floodplain vegetation in the Nxaraga Lagoon seasonal floodplains by sampling community composition and soil nutrient content in 1997, when flood levels were unusually low, and again in 2010 when flood levels were unusually high. In each of the eight ...

  17. Patterns and Seasonal Variations of Perforated Peptic Ulcer Disease

    African Journals Online (AJOL)

    multiruka1

    treatment is surgical. Objective: To describe the socio- demographics of the patients, seasonal variation in its incidence, modes of surgical management and outcome of patients. ... of Helicobacter pylori (H. pylori) as a causative agent in the 1980s. ... treatment is usually delayed hence with advanced peritonitis and sepsis.

  18. INTER-MARKET AND SEASONAL VARIATION IN PRICES: AN ...

    African Journals Online (AJOL)

    iya beji

    examined its seasonal price rise and analyzed the inter-market variation in prices of maize in the study area ... farmers are in business to sell their farm products at a fair returns or profit. ... from their investments and entrepreneurship. Therefore ...

  19. Seasonal Variation in Food Preference and Feeding Ecology of Two ...

    African Journals Online (AJOL)

    USER

    Seasonal Variation in Food Preference and Feeding Ecology of Two Juvenile. Marine Fishes, Pseudotolithus senegalensis (Sciaenidae) and Brachydeuterus auritus (Haemulidae) off Cape Coast, Ghana. J. Blay, Jr.1*, W. K. Awittor1 and D. Agbeko2. 1 Department of Fisheries and Aquatic Sciences, University of Cape Coast ...

  20. Determining wetland spatial extent and seasonal variations of the ...

    African Journals Online (AJOL)

    This study, done in the Witbank Dam Catchment in Mpumalanga Province of South Africa, explores a remote-sensing technique to delineate wetland extent and assesses the seasonal variations of the inundated area. The objective was to monitor the spatio-temporal changes of wetlands over time through remote sensing ...

  1. A seasonal variation of the three Leading diagnoses over fifty ...

    African Journals Online (AJOL)

    A seasonal variation of the three Leading diagnoses over fifty months at the Duk Lost. Boys Clinic, South Sudan reed, williama, Dannan, Tomb, Friedman Danielc, MD, Manyok gabrield, Connor Barbarae, MD, reed Davidf, MD. Introduction. The Duk Lost Boys Clinic, a Primary Health Care Clinic in Duk Payuel, is the only ...

  2. Seasonal variations of the high-latitude F region for

    International Nuclear Information System (INIS)

    Sojka, J.J.; Schunk, R.W.; Raitt, W.J.

    1982-01-01

    We combined a plasma convection model with an inosphere-atmospheric composition model in order to study the seasonal variations of the high-latitude F region for strong convection. Our numerical study produced time-dependent, three-dimensional, ion density distributions for the ions NO + , O 2 + , N 2 + , O + , N + , and He + . We covered the high-latitude ionosphere above 42 0 N magnetic latitude and at altitudes between 160 and 800 km for a time period of one complete day. From our study we found the following: (1) For strong convection, the high-altitude ionosphere exhibits a significant UT variation both during winter and summer. (2) In general, the electron density is lower in winter than in summer. However, at certain universal times the electron density in the dayside polar cap is larger in winter than in summer owing to the effect of the mid-latitude 'winter anomaly' in combination with strong antisunward convection. (3) In both summer and winter, the major region of low electron density is associated with the main or mid-latitudde trough. The trough is deeper and its local time extend is much greater in winter than in summer. (4) Typically, the electron density exhibits a much larger variation with altitude in winter than in summer. (5) The ion composition and molecular/atomic ion transition altitude are highly UT dependent in both summer and winter. (6) The ion composition also displays a significant seasonal variation. However, at a given location the seasonal variation can be opposite at different universal times. (7) High-speed convection cells should display a marked seasonal variation, with a much larger concentration of molecular ions near the F region peak in summer than in winter

  3. Seasonal variations in fouling diatom communities on the Yantai coast

    Science.gov (United States)

    Yang, Cuiyun; Wang, Jianhua; Yu, Yang; Liu, Sujing; Xia, Chuanhai

    2015-03-01

    Fouling diatoms are a main component of biofilm, and play an important role in marine biofouling formation. We investigated seasonal variations in fouling diatom communities that developed on glass slides immersed in seawater, on the Yantai coast, northern Yellow Sea, China, using microscopy and molecular techniques. Studies were conducted during 2012 and 2013 over 3, 7, 14, and 21 days in each season. The abundance of attached diatoms and extracellular polymeric substances increased with exposure time of the slides to seawater. The lowest diatom density appeared in winter and the highest species richness and diversity were found in summer and autumn. Seasonal variation was observed in the structure of fouling diatom communities. Pennate diatoms Cylindrotheca, Nitzschia, Navicula, Amphora, Gomphonema, and Licmophora were the main fouling groups. Cylindrotheca sp. dominated in the spring. Under laboratory culture conditions, we found that Cylindrotheca grew very fast, which might account for the highest density of this diatom in spring. The lower densities in summer and autumn might result from the emergence of fouling animals and environmental factors. The Cylindrotheca sp. was identified as Cylindrotheca closterium using18S rDNA sequencing. The colonization process of fouling diatoms and significant seasonal variation in this study depended on environmental and biological factors. Understanding the basis of fouling diatoms is essential and important for developing new antifouling techniques.

  4. Stable isotopes in a branching coral monitor seasonal temperature variation

    International Nuclear Information System (INIS)

    Dunbar, R.B.; Wellington, G.M.

    1981-01-01

    Results are reported of 18 O composition measurements of specimens of the branching reef coral Pocillopora damicornis, which have grown in the field, while seawater temperatures were continuously recorded. It is shown that seasonal temperature changes are accurately recorded by 18 O variations in branches of this reef coral and that isotopic profiles may be used to estimate growth rates of branching corals, which lack annual density banding. The method provides a technique for high resolution palaeoclimatic reconstruction of seasonal temperature ranges and accurate estimation of rates of reef carbonate production. (U.K.)

  5. Seasonal variation of physicochemical factor and fecal pollution in the Hansan-Geojeman area, Korea

    OpenAIRE

    Young Cheol Park; Poong Ho Kim; Yeoun Joong Jung; Ka Jeong Lee; Min Seon Kim; Kyeong Ri Go; Sang Gi Park; Soon Jae Kwon; Ji Hye Yang; Jong Soo Mok

    2016-01-01

    Abstract The seasonal variation of fecal coliforms (FCs) and physicochemical factors was determined in seawaters of the Hansan-Geojeman area, including a designated area for oyster, and in inland pollution sources of its drainage basin. The mean daily loads of FCs in inland pollution sources ranged from 1.2 × 109 to 3.1 × 1011 most probable number (MPN)/day; however, the pollutants could not be reached at the designated area. FC concentrations of seawaters were closely related to season, rain...

  6. Investigation of Seasonal Variation of groundwater Quality in Jimeta ...

    African Journals Online (AJOL)

    Sadiq

    chloride exceeded the recommended standards of drinking water quality in the rainy season ... supply, hygiene and exacerbating public health (Okoro ... source for human consumption and changes in quality ... Nigeria, has affected the availability of groundwater due .... carried out to define the impacts of waste water on.

  7. Modeling seasonal surface temperature variations in secondary tropical dry forests

    Science.gov (United States)

    Cao, Sen; Sanchez-Azofeifa, Arturo

    2017-10-01

    Secondary tropical dry forests (TDFs) provide important ecosystem services such as carbon sequestration, biodiversity conservation, and nutrient cycle regulation. However, their biogeophysical processes at the canopy-atmosphere interface remain unknown, limiting our understanding of how this endangered ecosystem influences, and responds to the ongoing global warming. To facilitate future development of conservation policies, this study characterized the seasonal land surface temperature (LST) behavior of three successional stages (early, intermediate, and late) of a TDF, at the Santa Rosa National Park (SRNP), Costa Rica. A total of 38 Landsat-8 Thermal Infrared Sensor (TIRS) data and the Surface Reflectance (SR) product were utilized to model LST time series from July 2013 to July 2016 using a radiative transfer equation (RTE) algorithm. We further related the LST time series to seven vegetation indices which reflect different properties of TDFs, and soil moisture data obtained from a Wireless Sensor Network (WSN). Results showed that the LST in the dry season was 15-20 K higher than in the wet season at SRNP. We found that the early successional stages were about 6-8 K warmer than the intermediate successional stages and were 9-10 K warmer than the late successional stages in the middle of the dry season; meanwhile, a minimum LST difference (0-1 K) was observed at the end of the wet season. Leaf phenology and canopy architecture explained most LST variations in both dry and wet seasons. However, our analysis revealed that it is precipitation that ultimately determines the LST variations through both biogeochemical (leaf phenology) and biogeophysical processes (evapotranspiration) of the plants. Results of this study could help physiological modeling studies in secondary TDFs.

  8. The distribution and seasonal variations of diffuse fraction

    International Nuclear Information System (INIS)

    Anane-Fenin, K.

    1989-06-01

    A moving average approach is used to develop linear and polynomial regression models for the diffuse fraction averaged over 10, 15, 20 and 30 days. The correlations do not appear to be influenced by climate conditions or altitude. It is noted that the correlations vary with season. The time-dependent variations of the diffuse fraction correlations are examined by studying the residual differences between the measured diffuse fraction and those calculated from the over-all best-fit correlation. The residuals exhibit no pronounced pattern leading to the conclusion that the observed seasonal variation is caused by air mass and water vapour and that atmospheric turbidity plays little or no part. (author). 14 refs, 9 figs, 8 tabs

  9. Seasonal variations of solar neutrino rates in lithium detector

    OpenAIRE

    Kopylov, Anatoly; Petukhov, Valery

    2002-01-01

    The presence of two monochromatic lines of approximately equal intensity: $^{7}$Be- and pep-neutrinos in the sensitivity plot of lithium detector makes the pattern of the seasonal variations of the effect from solar neutrinos very characteristic in case if the long-wave vacuum oscillations are realized. This can give the very high accuracy in the measurement of the parameters of neutrino oscillations especially if combined with the results obtained by the detector sensitive mainly to $^{7}$Be...

  10. Characteristics and seasonal variations of precipitation phenomena at Syowa Station

    Directory of Open Access Journals (Sweden)

    Hiroyuki Konishi

    1997-03-01

    Full Text Available Long-term observations of precipitating clouds were carried out by a vertical pointing radar, PPI radar and a 37 GHz microwave radiometer at Syowa Station (69°00′S, 39°35′E, Antarctica in 1989. It is concluded from the observations that precipitation near Syowa Station, Antarctica is mainly brought by cloud vortices associated with extratropical cyclones which advance to high latitude while developing to a mature stage. The seasonal variations of clouds and precipitation were analyzed corresponding to the seasonal changes of air temperature and sea ice area. The occurrence frequencies of cloud vortices which brought snowfall to Syowa Station increased in the fall and spring seasons corresponding to activity of the circumpolar trough. However, the activities of cloud systems that bring precipitation weaken in spring when the sea ice area expands to low latitudes, because of less supply of heat and vapor. In 1989,the amount of precipitation in spring brought by a few snowfall events was as large as the amount of precipitation in fall brought by frequent snowfall events. Radar observations revealed that there were three abundant snowfall seasons at Syowa Station and the amount of snowfall was uniform in all seasons except summer. The amounts of precipitation in fall, winter and spring were 74,74 and 53mm respectively.

  11. Season-to-Season Variations of Physiological Fitness Within a Squad of Professional Male Soccer Players

    Science.gov (United States)

    Clark, Niall A.; Edwards, Andrew M.; Morton, R. Hugh; Butterly, Ronald J.

    2008-01-01

    The purpose of this study was to examine season-to-season variations in physiological fitness parameters among a 1st team squad of professional adult male soccer players for the confirmatory purposes of identifying normative responses (immediately prior to pre-season training (PPS), mid-season (MID), and end-of-season (EOS)). Test-retest data were collected from a student population on the primary dependent variables of anaerobic threshold (AT) and maximal aerobic power (VO2 max) to define meaningful measurement change in excess of test-retest technical error between test-to-test performances. Participants from a pool of 42 professional soccer players were tested over a set sequence of tests during the 3-year period: 1) basic anthropometry, 2) countermovement jump (CMJ) tests 3) a combined AT and VO2 max test. Over the 3-year period there were no test-to-test changes in mean VO2 max performance exceeding pre-defined limits of test agreement (mean of eight measures: 61.6 ± 0.6 ml·kg-1·min-1). In contrast, VO2 at AT was significantly higher at the MID test occasion in seasons 2 (+4.8%; p = 0.04, p elite cohort between test-to-test occasions, VO2 max values did not vary significantly over the study which supports previous short-term observations suggesting a general ‘elite’ threshold of 60 ml·kg-1 min. Interestingly, AT significantly varied where VO2 max was stable and these variations also coincided with on- and off-seasons suggesting that AT is a better indication of acute training state than VO2 max. Key points Maximal aerobic power remains fairly stable across inter- and intra-season measurements. Anaerobic threshold appears more sensitive of training state confirming our earlier observations. The professional players tended to attain optimal performances at the mid-season interval over the 3 seasons, presumably prior to the development of accumulative fatigue. PMID:24150149

  12. Seasonal variations in vertical migration of glacier lanternfish, Benthosema glaciale

    KAUST Repository

    Dypvik, Eivind; Rø stad, Anders; Kaartvedt, Stein

    2012-01-01

    The seasonal variations in glacier lanternfish (Benthosema glaciale) vertical distribution and diel vertical migration (DVM) were studied by use of a bottom-mounted upward-facing 38 kHz echo sounder deployed at 392 m depth and cabled to shore in Masfjorden (~6052?N, ~524?E), Norway. Acoustic data from July 2007-October 2008 were analyzed, and scattering layers below ~220 m during daytime were attributed to glacier lanternfish based on net sampling in this, and previous studies, as well as from analysis of the acoustic data. At these depths, three different diel behavioral strategies were apparent: normal diel vertical migration (NDVM), inverse DVM (IDVM), and no DVM (NoDVM). NoDVM was present all year, while IDVM was present in autumn and winter, and NDVM was present during spring and summer. The seasonal differences in DVM behavior seem to correlate with previously established seasonal distribution of prey. We hypothesize that in regions with seasonally migrating zooplankton, such as where calanoid copepods overwinter at depth, similar plasticity in DVM behavior might occur in other populations of lanternfishes. 2012 The Author(s).

  13. Seasonal variations in vertical migration of glacier lanternfish, Benthosema glaciale

    KAUST Repository

    Dypvik, Eivind

    2012-06-05

    The seasonal variations in glacier lanternfish (Benthosema glaciale) vertical distribution and diel vertical migration (DVM) were studied by use of a bottom-mounted upward-facing 38 kHz echo sounder deployed at 392 m depth and cabled to shore in Masfjorden (~6052?N, ~524?E), Norway. Acoustic data from July 2007-October 2008 were analyzed, and scattering layers below ~220 m during daytime were attributed to glacier lanternfish based on net sampling in this, and previous studies, as well as from analysis of the acoustic data. At these depths, three different diel behavioral strategies were apparent: normal diel vertical migration (NDVM), inverse DVM (IDVM), and no DVM (NoDVM). NoDVM was present all year, while IDVM was present in autumn and winter, and NDVM was present during spring and summer. The seasonal differences in DVM behavior seem to correlate with previously established seasonal distribution of prey. We hypothesize that in regions with seasonally migrating zooplankton, such as where calanoid copepods overwinter at depth, similar plasticity in DVM behavior might occur in other populations of lanternfishes. 2012 The Author(s).

  14. Seasonal variation of radon concentration in different rooms of dwellings

    International Nuclear Information System (INIS)

    Jayasheelan, A.; Manjunatha, S.; Chandrashekaraiah, G.; Shankar, P.; Umeshareddy, K.; Ningappa, C.

    2016-01-01

    Indoor air is a dominant exposure for humans, where more than half of the body's intake during a lifetime. The main natural sources of indoor radon are soil, building materials like sand, rocks, cement, marble, bricks, ceramics, natural gas and the underground-derived water supply. In the present research, dwellings with similar building style (similar floorings and dimensions) from Tumkur city were studied for indoor radon, thoron and their progeny measurements for various seasons

  15. Seasonal and spatial variation of trace elements and metals in quasi-ultrafine (PM0.25) particles in the Los Angeles metropolitan area and characterization of their sources

    International Nuclear Information System (INIS)

    Saffari, Arian; Daher, Nancy; Shafer, Martin M.; Schauer, James J.; Sioutas, Constantinos

    2013-01-01

    Year-long sampling campaign of quasi-ultrafine particles (PM 0.25 ) was conducted at 10 distinct locations across the Los Angeles south coast air basin and concentrations of trace elements and metals were quantified at each site using high-resolution inductively coupled plasma sector field mass spectrometry. In order to characterize sources of trace elements and metals, principal component analysis (PCA) was applied to the dataset. The major sources were identified as road dust (influenced by vehicular emissions as well as re-suspended soil), vehicular abrasion, residual oil combustion, cadmium sources and metal plating. These sources altogether accounted for approximately 85% of the total variance of quasi-ultrafine elemental content. The concentrations of elements originating from source and urban locations generally displayed a decline as we proceeded from the coast to the inland. Occasional concentration peaks in the rural receptor sites were also observed, driven by the dominant westerly/southwesterly wind transporting the particles to the receptor areas. -- Highlights: •We collected quasi-ultrafine samples at 10 locations across the Los Angeles Basin. •The concentration of trace elements and metals at each site were quantified. •Distinct temporal and spatial variability was observed across the basin. •Principal component analysis was applied to the data to characterize the sources. •Five major sources were identified for quasi-ultrafine elemental content. -- Characterization of sources of trace elements and metals in quasi-ultrafine particles in the Los Angeles south coast air basin and explaining their seasonal and spatial variability

  16. Seasonal variations in VOC emission rates from gorse (Ulex europaeus)

    Science.gov (United States)

    Boissard, C.; Cao, X.-L.; Juan, C.-Y.; Hewitt, C. N.; Gallagher, M.

    Seasonal variations of biogenic volatile organic compound (VOC) emission rates and standardised emission factors from gorse (Ulex europaeus) have been measured at two sites in the United Kingdom, from October 1994 to September 1995, within temperature and PAR conditions ranging from 3 to 34°C and 10-1300 μmol m-2 s-1, respectively. Isoprene was the dominant emitted compound with a relative composition fluctuating from 7% of the total VOC (winter) to 97% (late summer). The monoterpenes α-pinene, camphene, sabinene, β-pinene, myrcene, limonene, trans-ocimene and γ-terpinene were also emitted, with α-pinene being the dominant monoterpene during most the year. Trans-ocimene represented 33-66% of the total monoterpene during the hottest months from June to September. VOC emissions were found to be accurately predicted using existing algorithms. Standard (normalised) emission factors of VOCs from gorse were calculated using experimental parameters measured during the experiment and found to fluctuate with season, from 13.3±2.1 to 0.1±0.1 μg C (g dwt)-1 h-1 in August 1995 and January 1995, respectively, for isoprene, and from 2.5±0.2 to 0.4±0.2 μg C (g dwt)-1 h-1 in July and November 1995, respectively, for total monoterpenes. No simple clear relation was found to allow prediction of these seasonal variations with respect to temperature and light intensity. The effects of using inappropriate algorithms to derive VOC fluxes from gorse were assessed for isoprene and monoterpenes. Although on an annual basis the discrepancies are not significant, monthly estimation of isoprene were found to be overestimated by more than a factor of 50 during wintertime when the seasonality of emission factors is not considered.

  17. Background levels of methane in Mars’ atmosphere show strong seasonal variations

    Science.gov (United States)

    Webster, Christopher R.; Mahaffy, Paul R.; Atreya, Sushil K.; Moores, John E.; Flesch, Gregory J.; Malespin, Charles; McKay, Christopher P.; Martinez, German; Smith, Christina L.; Martin-Torres, Javier; Gomez-Elvira, Javier; Zorzano, Maria-Paz; Wong, Michael H.; Trainer, Melissa G.; Steele, Andrew; Archer, Doug; Sutter, Brad; Coll, Patrice J.; Freissinet, Caroline; Meslin, Pierre-Yves; Gough, Raina V.; House, Christopher H.; Pavlov, Alexander; Eigenbrode, Jennifer L.; Glavin, Daniel P.; Pearson, John C.; Keymeulen, Didier; Christensen, Lance E.; Schwenzer, Susanne P.; Navarro-Gonzalez, Rafael; Pla-García, Jorge; Rafkin, Scot C. R.; Vicente-Retortillo, Álvaro; Kahanpää, Henrik; Viudez-Moreiras, Daniel; Smith, Michael D.; Harri, Ari-Matti; Genzer, Maria; Hassler, Donald M.; Lemmon, Mark; Crisp, Joy; Sander, Stanley P.; Zurek, Richard W.; Vasavada, Ashwin R.

    2018-06-01

    Variable levels of methane in the martian atmosphere have eluded explanation partly because the measurements are not repeatable in time or location. We report in situ measurements at Gale crater made over a 5-year period by the Tunable Laser Spectrometer on the Curiosity rover. The background levels of methane have a mean value 0.41 ± 0.16 parts per billion by volume (ppbv) (95% confidence interval) and exhibit a strong, repeatable seasonal variation (0.24 to 0.65 ppbv). This variation is greater than that predicted from either ultraviolet degradation of impact-delivered organics on the surface or from the annual surface pressure cycle. The large seasonal variation in the background and occurrences of higher temporary spikes (~7 ppbv) are consistent with small localized sources of methane released from martian surface or subsurface reservoirs.

  18. Circadian and seasonal variation of migraine attacks in children.

    Science.gov (United States)

    Soriani, Stefano; Fiumana, Elisa; Manfredini, Roberto; Boari, Benedetta; Battistella, Pier Antonio; Canetta, Elisabetta; Pedretti, Stefania; Borgna-Pignatti, Caterina

    2006-01-01

    To investigate the rhythmicity of migraine episodes without aura in a pediatric population. Time of occurrence of 2517 migraine attacks in 115 children was recorded, by means of a diary, both by hourly and monthly intervals. A significant circadian variation, characterized by a peak in the afternoon (P < .001) and one in the early morning (P= .002) was found. A seasonal peak was also observed between November and January, while a nadir was observed in July. The clustering of attacks in the morning and midday and in autumn-winter, with a minimum frequency in July, suggests that school activities may represent an important cause of migraine.

  19. Residential radon in Finland: sources, variation, modelling and dose comparisons

    Energy Technology Data Exchange (ETDEWEB)

    Arvela, H

    1995-09-01

    The study deals with sources of indoor radon in Finland, seasonal variations in radon concentration, the effect of house construction and ventilation and also with the radiation dose from indoor radon and terrestrial gamma radiation. The results are based on radon measurements in approximately 4000 dwellings and on air exchange measurements in 250 dwellings as well as on model calculations. The results confirm that convective soil air flow is by far the most important source of indoor radon in Finnish low-rise residential housing. (97 refs., 61 figs., 30 tabs.).

  20. Residential radon in Finland: sources, variation, modelling and dose comparisons

    International Nuclear Information System (INIS)

    Arvela, H.

    1995-09-01

    The study deals with sources of indoor radon in Finland, seasonal variations in radon concentration, the effect of house construction and ventilation and also with the radiation dose from indoor radon and terrestrial gamma radiation. The results are based on radon measurements in approximately 4000 dwellings and on air exchange measurements in 250 dwellings as well as on model calculations. The results confirm that convective soil air flow is by far the most important source of indoor radon in Finnish low-rise residential housing. (97 refs., 61 figs., 30 tabs.)

  1. Seasonal variation in thrombogenicity of blood: a word of caution.

    Science.gov (United States)

    Narang, Sumit; Banerjee, Amit; Satsangi, Deepak K; Geelani, Mohammad A

    2009-01-01

    Thrombogenicity of blood is known to have seasonal variations. The clinical implications of seasonal variations in the anticoagulation profile of patients with mechanical valves was assessed. Data of patients implanted with a mechanical heart valve for more than 3 months were collected at follow-up or on presentation to the emergency department. The mean time from the previous follow-up examination was 3.6 +/- 0.3 months. The number of patients with an international normalized ratio >3.5 and the incidence of hemorrhagic events peaked in hottest part of the year (June-July), with 128 cases of prolonged clotting and 43 hemorrhagic events in this period. The number of patients with rapid clotting and the incidence of embolic events peaked in coldest part of the year (December-January), with 120 cases of international normalized ratio <1.5 and 37 embolic events in this period. There was a significant correlation between temperature and thrombogenicity in patients with prosthetic heart valves on long-term anticoagulation.

  2. Characteristics of seasonal variation and solar activity dependence of the geomagnetic solar quiet daily variation

    Science.gov (United States)

    Shinbori, A.; Koyama, Y.; Nose, M.; Hori, T.

    2017-12-01

    Characteristics of seasonal variation and solar activity dependence of the X- and Y-components of the geomagnetic solar quiet (Sq) daily variation at Memanbetsu in mid-latitudes and Guam near the equator have been investigated using long-term geomagnetic field data with 1-h time resolution from 1957 to 2016. In this analysis, we defined the quiet day when the maximum value of the Kp index is less than 3 for that day. In this analysis, we used the monthly average of the adjusted daily F10.7 corresponding to geomagnetically quiet days. For identification of the monthly mean Sq variation in the X and Y components (Sq-X and Sq-Y), we first determined the baseline of the X and Y components from the average value from 22 to 2 h (LT: local time) for each quiet day. Next, we calculated a deviation from the baseline of the X- and Y-components of the geomagnetic field for each quiet day, and computed the monthly mean value of the deviation for each local time. As a result, Sq-X and Sq-Y shows a clear seasonal variation and solar activity dependence. The amplitude of seasonal variation increases significantly during high solar activities, and is proportional to the solar F10.7 index. The pattern of the seasonal variation is quite different between Sq-X and Sq-Y. The result of the correlation analysis between the solar F10.7 index and Sq-X and Sq-Y shows almost the linear relationship, but the slope and intercept of the linear fitted line varies as function of local time and month. This implies that the sensitivity of Sq-X and Sq-Y to the solar activity is different for different local times and seasons. The local time dependence of the offset value of Sq-Y at Guam and its seasonal variation suggest a magnetic field produced by inter-hemispheric field-aligned currents (FACs). From the sign of the offset value of Sq-Y, it is infer that the inter-hemispheric FACs flow from the summer to winter hemispheres in the dawn and dusk sectors and from the winter to summer hemispheres in

  3. Effects of seasonal variations on thermoregulation of ostrich

    International Nuclear Information System (INIS)

    Basuony, H.A.M.

    2011-01-01

    Twelve ostrich aged 7 months old were used during summer and winter from the breeding flock of the ostrich farm, at the Nuclear Research Center in Inshas, of Atomic Energy Authority, Egypt. In the study all birds were exposed to ambient temperatures in summer and winter, and the birds were fed grower ration ad libitum (19% protein and 2450 K cal ME /Kg).The present study was carried out to evaluate the effect of temperature variation during summer and winter seasons and diurnal effect on changes in some physiological and blood chemical parameters, the daily feed consumption (g/bird/day) and water consumption (ml/bird/day) these parameters were measured during 7 days in each season. Cloacal temperatures was measured and blood samples were taken twice, one in the morning at 7 am and once in the afternoon at 3 pm during a representative 7 hot days of June (40±2 degree C) (summer) and the 7 cold days of January (18±2 degree C) (winter). Red blood cell (RBCs) counts and total white blood cell (WBCs) counts, hemoglobin concentration (Hb) and packed cell volume (PCV) were determined. Mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular hemoglobin concentrations (MCHC) were calculated. Serum, total protein (TP), albumen (A) and globulin (G) concentrations were measured. Furthermore, serum alanine transaminase (ALT), aspartate transaminase (AST), glucose and triglycerides concentrations were determined. Also, serum triiodothyronine (T 3 ), and aldosterone levels were estimated. Also, the amount of total body water was determined by the antipyren method. Finally, serum protein profile it was conducted by Native-PAGE method (Native polyacrylamide gel electrophoresis) on vertical slab gel to determine protein profiles in blood proteins of ostrich. Results indicated that feed consumption unlike water consumption was significantly increased during winter than in summer season. Moreover, body temperature increased significantly during the

  4. Seasonal variation of seismic ambient noise level at King Sejong Station, Antarctica

    Science.gov (United States)

    Lee, W.; Sheen, D.; Seo, K.; Yun, S.

    2009-12-01

    The generation of the secondary- or double-frequency (DF) microseisms with dominant frequencies between 0.1 and 0.5 Hz has been explained by nonlinear second-order pressure perturbations on the ocean bottom due to the interference of two ocean waves of equal wavelengths traveling in opposite directions. Korea Polar Research Institute (KOPRI) has been operating a broadband seismic station (KSJ1) at King George Island (KGI), Antarctica, since 2001. Examining the ambient seismic noise level for the period from 2006 to 2008 at KSJ1, we found a significant seasonal variation in the frequency range 0.1-0.5 Hz. Correlation of the DF peaks with significant ocean wave height and peak wave period models indicates that the oceanic infragravity waves in the Drake Passage is a possible source to excite the DF microseisms at KGI. Location of King Sejong Station, Antarctica Seasonal variations of DF peak, significant wave height, and peak wave period

  5. Seasonal variation of diseases in children : a 6-year prospective cohort study in a general hospital

    NARCIS (Netherlands)

    Schrijver, Tessa V.; Brand, Paul L. P.; Bekhof, Jolita

    Seasonal variation in pediatrics has been well described in some infectious diseases, asthma, and diabetes, but data on seasonality for other diseases in children are sparse. To explore the extent of seasonal variation of the entire pediatric field, we analyzed diagnostic codes of all newly referred

  6. ATHENS SEASONAL VARIATION OF GROUND RESISTANCE PREDICTION USING NEURAL NETWORKS

    Directory of Open Access Journals (Sweden)

    S. Anbazhagan

    2015-10-01

    Full Text Available The objective in ground resistance is to attain the most minimal ground safety esteem conceivable that bodes well monetarily and physically. An application of artificial neural networks (ANN to presage and relegation has been growing rapidly due to sundry unique characteristics of ANN models. A decent forecast is able to capture the dubiousness associated with those ground resistance. A portion of the key instabilities are soil composition, moisture content, temperature, ground electrodes and spacing of the electrodes. Propelled by this need, this paper endeavors to develop a generalized regression neural network (GRNN to predict the ground resistance. The GRNN has a single design parameter and expeditious learning and efficacious modeling for nonlinear time series. The precision of the forecast is applied to the Athens seasonal variation of ground resistance that shows the efficacy of the proposed approach.

  7. Seasonal variation of air pollution in Warsaw conurbation

    Directory of Open Access Journals (Sweden)

    Katarzyna Rozbicka

    2014-09-01

    Full Text Available Long term research shows many substances in the atmosphere are in concentration dangerous for human health and welfare and even for human life. The work presents time and spatial variation of tropospheric ozone and nitrogen dioxide concentrations. Analysis was carried out on the base of hourly values of mentioned pollutants (O3 and NO2 concentrations. Data used in the analysis comes from atmospheric monitoring stations situated in various parts of Warsaw and concerns the period 2008–2011. The influence of meteorological elements on concentration of analyzed pollutants was stated by the use of correlation and multiple regression analysis for months and seasonal periods. On this base results of statistical analysis strong correlation between tropospheric ozone, nitrogen dioxide concentration and meteorological elements is stated. In case of ozone and nitrogen dioxide the relationships with air temperature, relative humidity and solar radiation are most significant.

  8. Seasonal variation among tuberculosis suspects in four countries

    DEFF Research Database (Denmark)

    Mabaera, Biggie; Naranbat, Nymadawa; Katamba, Achilles

    2009-01-01

    The objective of the study was to analyze monthly trends across a calendar year in tuberculosis suspects and sputum smear-positive cases based on nationally representative samples of tuberculosis laboratory registers from Moldova, Mongolia, Uganda and Zimbabwe. Out of the 47 140 suspects registered...... in the tuberculosis laboratory registers, 13.4% (6312) were cases. The proportion varied from country to country, Moldova having the lowest (9%) and Uganda the highest (21%). From the monthly proportion of suspects and cases among total suspects and cases, seasonal variations were most marked in Mongolia which, among...... attendance to diagnostic laboratory services, evidenced by the contrasting findings of Mongolia (extreme continental northern climate) compared to Uganda (equatorial climate). A combination of external and possibly endogenous factors seems to determine whether tuberculosis suspects and cases present...

  9. Marked seasonal variation in the wild mouse gut microbiota.

    Science.gov (United States)

    Maurice, Corinne F; Knowles, Sarah C L; Ladau, Joshua; Pollard, Katherine S; Fenton, Andy; Pedersen, Amy B; Turnbaugh, Peter J

    2015-11-01

    Recent studies have provided an unprecedented view of the microbial communities colonizing captive mice; yet the host and environmental factors that shape the rodent gut microbiota in their natural habitat remain largely unexplored. Here, we present results from a 2-year 16 S ribosomal RNA gene sequencing-based survey of wild wood mice (Apodemus sylvaticus) in two nearby woodlands. Similar to other mammals, wild mice were colonized by 10 bacterial phyla and dominated by the Firmicutes, Bacteroidetes and Proteobacteria. Within the Firmicutes, the Lactobacillus genus was most abundant. Putative bacterial pathogens were widespread and often abundant members of the wild mouse gut microbiota. Among a suite of extrinsic (environmental) and intrinsic (host-related) factors examined, seasonal changes dominated in driving qualitative and quantitative differences in the gut microbiota. In both years examined, we observed a strong seasonal shift in gut microbial community structure, potentially due to the transition from an insect- to a seed-based diet. This involved decreased levels of Lactobacillus, and increased levels of Alistipes (Bacteroidetes phylum) and Helicobacter. We also detected more subtle but statistically significant associations between the gut microbiota and biogeography, sex, reproductive status and co-colonization with enteric nematodes. These results suggest that environmental factors have a major role in shaping temporal variations in microbial community structure within natural populations.

  10. Periodic seasonal variation of magnets level of the STB ring

    International Nuclear Information System (INIS)

    Takahashi, Shigenobu

    2003-01-01

    The Stretcher-Booster (STB) ring, a 1.2 GeV electron synchrotron, was completed in December, 1997 at the Laboratory of Nuclear Sciences (LNS), Tohoku University. The total weight more than 400 tons were placed near the STB ring, such as concrete blocks for radiation shielding and a spectrometer magnet for nuclear physics experiments after the completion of the STB ring. Re-surveying of magnets alignment was started after 2000. Very recently a new building of an experimental hall was constructed close to the building of the STB ring for use of high energy γ-ray from the electron beam. The building will give rise the changes of magnet levels due to its seasonal distortion. The measurements of the magnet level after construction are continued as well as an expected change of the closed orbit distortion (COD) in the STB ring. The serious influence of the variation of the magnet level may be a change of the beam orbit of extracted beam in the stretcher operation. Difference of the orbit distortion reaches more than 5 mm. Correlation between the COD and the seasonal change of the magnet position is not clear at the moment. However, the machine operation and the beam diagnostics are getting better recently. Continuous surveying of the magnet level will be a useful data for a feed forward correction of the beam orbit. Future subjects and prospects are discussed on surveying. (Y. Tanaka)

  11. Seasonal Variation in the Emergency Department Prevalence Of Sepsis

    LENUS (Irish Health Repository)

    McNevin, C

    2018-05-01

    The incidence and mortality of sepsis and severe sepsis in hospitalised patients is seasonal and consistently highest during the winter. The primary aim of this study was to measure the seasonal variation in the prevalence of emergency department (ED) patients with sepsis. This cross-sectional study was performed over two four-week periods in the summer and in the winter, respectively. The clinical records of all patients presenting to the ED during the study periods were retrospectively screened to determine if they met the criteria for “uncomplicated” sepsis and severe sepsis or septic shock. The prevalence of “uncomplicated” sepsis was higher in the winter (43.9 per 1000) compared to the summer (30.7 per 1000). The prevalence of severe sepsis or septic shock was also higher in the winter (17.7 per 1000) compared to the summer (11.7 per 1000). This quantitatively demonstrates the increased ED burden of sepsis in the winter that can be used to inform healthcare planning and resource allocation.

  12. Seasonal and spatial variations of atmospheric trace elemental deposition in the Aliaga industrial region, Turkey

    Science.gov (United States)

    Kara, Melik; Dumanoglu, Yetkin; Altiok, Hasan; Elbir, Tolga; Odabasi, Mustafa; Bayram, Abdurrahman

    2014-11-01

    Atmospheric bulk deposition (wet + dry deposition) samples (n = 40) were collected concurrently at ten sites in four seasons between June 2009 and April 2010 in the Aliaga heavily industrialized region, Turkey, containing a number of significant air pollutant sources. Analyses of trace elements were carried out using inductively coupled plasma-mass spectrometry (ICP-MS). While there were significant differences in the particulate matter (PM) deposition fluxes among the sampling sites, seasonal variations were not statistically significant (Kruskal-Wallis test, p < 0.05). Both PM deposition and elemental fluxes were increased at the sampling sites in the vicinity of industrial activities. The crustal elements (i.e., Ca, Mg) and some anthropogenic elements (such as Fe, Zn, Mn, Pb, Cu, and Cr) were high, and the highest fluxes were mostly measured in summer and winter seasons. The enrichment factor (EF) and principal component analysis (PCA) was applied to the data to determine the possible sources in the study area. High EF values were obtained for the anthropogenic elements such as Ag, Cd, Zn, Pb, Cu and Sb. The possible sources were identified as anthropogenic sources (i.e., iron-steel production) (45.4%), crustal and re-suspended dust (27.1%), marine aerosol (7.9%), and coal and wood combustion (8.2%). Thus, the iron-steel production and its related activities were found to be the main pollutant sources for this region.

  13. Two distinct patterns of seasonal variation of airborne black carbon over Tibetan Plateau

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Mo; Xu, Baiqing; Wang, Ninglian; Cao, Junji; Tie, Xuexi; Wang, Hailong; Zhu, Chongshu; Yang, Wei

    2016-12-01

    Airborne black carbon (BC) mass concentrations were measured from November 2012 to June 2013 at Ranwu and Beiluhe, located in the southeastern and central Tibetan Plateau, respectively. Monthly mean BC concentrations showawinter (November–February) high (413.2 ng m$-$3) and spring (March–June) low(139.1 ng m$-$3) at Ranwu, but in contrast awinter lowand spring high at Beiluhe (204.8 and 621.6 ng m$-$3, respectively). By examining the meteorological conditions at various scales, we found that themonthly variation of airborne BC over the southeastern Tibetan Plateau (TP) was highly influenced by regional precipitation and over the hinterland by winds. Local precipitation at both sites showed little impact on the seasonal variation of airborne BC concentrations. Potential BC source regions are identified using air mass backward trajectory analysis. At Ranwu, BC was dominated by the air masses from the northeastern India and Bangladesh in both winter and spring, whereas at Beiluhe it was largely contributed by air masses from the south slope of Himalayas in winter, and from the arid region in the north of the TP in spring. Thewinter and spring seasonal peak of BC in the southern TP is largely contributed by emissions from South Asia, and this seasonal variation is heavily influenced by the regional monsoon. In the northern TP, BC had high concentrations during spring and summer seasons, which is very likely associated with more efficient transport of BC over the arid regions on the north of Tibetan Plateau and in Central Asia. Airborne BC concentrations at the Ranwusampling site showed a significant diurnal cyclewith a peak shortly after sunrise followed by a decrease before noon in both winter and spring, likely shaped by local human activities and the diurnal variation of wind speed. At the Beiluhe sampling site, the diurnal variation of BC is different and less distinct.

  14. Two distinct patterns of seasonal variation of airborne black carbon over Tibetan Plateau.

    Science.gov (United States)

    Wang, Mo; Xu, Baiqing; Wang, Ninglian; Cao, Junji; Tie, Xuexi; Wang, Hailong; Zhu, Chongshu; Yang, Wei

    2016-12-15

    Airborne black carbon (BC) mass concentrations were measured from November 2012 to June 2013 at Ranwu and Beiluhe, located in the southeastern and central Tibetan Plateau, respectively. Monthly mean BC concentrations show a winter (November-February) high (413.2ngm -3 ) and spring (March-June) low (139.1ngm -3 ) at Ranwu, but in contrast a winter low and spring high at Beiluhe (204.8 and 621.6ngm -3 , respectively). By examining the meteorological conditions at various scales, we found that the monthly variation of airborne BC over the southeastern Tibetan Plateau (TP) was highly influenced by regional precipitation and over the hinterland by winds. Local precipitation at both sites showed little impact on the seasonal variation of airborne BC concentrations. Potential BC source regions are identified using air mass backward trajectory analysis. At Ranwu, BC was dominated by the air masses from the northeastern India and Bangladesh in both winter and spring, whereas at Beiluhe it was largely contributed by air masses from the south slope of Himalayas in winter, and from the arid region in the north of the TP in spring. The winter and spring seasonal peak of BC in the southern TP is largely contributed by emissions from South Asia, and this seasonal variation is heavily influenced by the regional monsoon. In the northern TP, BC had high concentrations during spring and summer seasons, which is very likely associated with more efficient transport of BC over the arid regions on the north of Tibetan Plateau and in Central Asia. Airborne BC concentrations at the Ranwu sampling site showed a significant diurnal cycle with a peak shortly after sunrise followed by a decrease before noon in both winter and spring, likely shaped by local human activities and the diurnal variation of wind speed. At the Beiluhe sampling site, the diurnal variation of BC is different and less distinct. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. seasonal variation in water quality of orle river basin, sw nigeria.

    African Journals Online (AJOL)

    LUCY

    The seasonal variation of water quality of Orle River and its tributatries in S.W. Nigeria was investigated forthnightly or two ... KEYWORD: water quality, river basin, wet and dry seasons; pollution. ..... Environmental Modeling and Software,.

  16. Latitudinal and seasonal variations of lower atmospheric inertial gravity wave energy revealed by US radiosonde data

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, S.D.; Yi, F. [Wuhan Univ., Hubei (China). School of Electronic Information; Ministry of Education, Wuhan, Hubei (China). Key Lab. of Geospace Environment and Geodesy; State Observatory for Atmospheric Remote Sensing, Wuhan (China); Huang, C.M. [Wuhan Univ., Hubei (China). School of Electronic Information; Ministry of Education, Wuhan, Hubei (China). Key Lab. of Geospace Environment and Geodesy; State Observatory for Atmospheric Remote Sensing, Wuhan (China); Miami Univ., Oxford, OH (United States). Electrical and Computer Engineering Dept.; Zhou, Q. [Miami Univ., Oxford, OH (United States). Electrical and Computer Engineering Dept.

    2010-07-01

    The latitudinal and seasonal variations of gravity wave (GW) potential energy density (E{sub P}), kinetic energy density (E{sub K}), and total energy density (E{sub T}), i.e, the sum of potential and kinetic energy densities in the tropospheric (typically 2-10 km) and lower stratospheric (typically 18- 25 km) segments have been derived from 10 years (1998- 2007) of radiosonde observations over 92 United States stations in the Northern Hemisphere. The latitudinal variation of E{sub P} in the lower stratosphere is in good agreement with satellite observations. However, E{sub K} and E{sub T} in the lower stratosphere are different from satellite observations and the difference is believed to be linked with the latitudinal dependence of GW sources. Our analysis reveals that GW energy properties exhibit distinctive latitudinal and seasonal variations. The upward-propagating GW energy in the troposphere is larger than that in the lower stratosphere at low latitudes but the opposite holds true at high latitudes. The transition latitude, where the upward- propagating energies in the two altitude regions are the same, occurs at 35 N throughout the year. So striking differences between GW activity in the troposphere and lower stratosphere are not likely explained only by the background wind Doppler shifting due to strong tropospheric jets. Our analysis indicates that the region around tropopause, roughly from 10 km to 18 km, is an important source region, especially at latitudes below 35 N. Our studies strongly suggest that in order to fully understand the global GW activity in the lower atmosphere, the GW kinetic energy and its geographical and seasonal variations should be included, and more attention should be given to GWs in the troposphere and GW sources within the intermediate region, especially the upper troposphere. (orig.)

  17. Latitudinal and seasonal variations of lower atmospheric inertial gravity wave energy revealed by US radiosonde data

    Directory of Open Access Journals (Sweden)

    S. D. Zhang

    2010-05-01

    Full Text Available The latitudinal and seasonal variations of gravity wave (GW potential energy density (EP, kinetic energy density (EK, and total energy density (ET, i.e, the sum of potential and kinetic energy densities in the tropospheric (typically 2–10 km and lower stratospheric (typically 18–25 km segments have been derived from 10 years (1998–2007 of radiosonde observations over 92 United States stations in the Northern Hemisphere. The latitudinal variation of EP in the lower stratosphere is in good agreement with satellite observations. However, EK and ET in the lower stratosphere are different from satellite observations and the difference is believed to be linked with the latitudinal dependence of GW sources. Our analysis reveals that GW energy properties exhibit distinctive latitudinal and seasonal variations. The upward-propagating GW energy in the troposphere is larger than that in the lower stratosphere at low latitudes but the opposite holds true at high latitudes. The transition latitude, where the upward- propagating energies in the two altitude regions are the same, occurs at 35° N throughout the year. So striking differences between GW activity in the troposphere and lower stratosphere are not likely explained only by the background wind Doppler shifting due to strong tropospheric jets. Our analysis indicates that the region around tropopause, roughly from 10 km to 18 km, is an important source region, especially at latitudes below 35° N. Our studies strongly suggest that in order to fully understand the global GW activity in the lower atmosphere, the GW kinetic energy and its geographical and seasonal variations should be included, and more attention should be given to GWs in the troposphere and GW sources within the intermediate region, especially the upper troposphere.

  18. Seasonal variation in Internet searches for vitamin D.

    Science.gov (United States)

    Moon, Rebecca J; Curtis, Elizabeth M; Davies, Justin H; Cooper, Cyrus; Harvey, Nicholas C

    2017-12-01

    Internet search rates for "vitamin D" were explored using Google Trends. Search rates increased from 2004 until 2010 and thereafter displayed a seasonal pattern peaking in late winter. This knowledge could help guide the timing of public health interventions aimed at managing vitamin D deficiency. The Internet is an important source of health information. Analysis of Internet search activity rates can provide information on disease epidemiology, health related behaviors and public interest. We explored Internet search rates for vitamin D to determine whether this reflects the increasing scientific interest in this topic. Google Trends is a publically available tool that provides data on Internet searches using Google. Search activity for the term "vitamin D" from 1st January 2004 until 31st October 2016 was obtained. Comparison was made to other bone and nutrition related terms. Worldwide, searches for "vitamin D" increased from 2004 until 2010 and thereafter a statistically significant (p Internet search activity, did increase from 2004 to 2010, likely reflecting the growing scientific interest, but now displays a seasonal pattern with peak interest during late winter. This information could be used to guide public health approaches to managing vitamin D deficiency.

  19. Seasonal and Diurnal Variations of Atmospheric Non-Methane Hydrocarbons in Guangzhou, China

    Directory of Open Access Journals (Sweden)

    Longfeng Li

    2012-05-01

    Full Text Available In recent decades, high ambient ozone concentrations have become one of the major regional air quality issues in the Pearl River Delta (PRD region. Non-methane hydrocarbons (NMHCs, as key precursors of ozone, were found to be the limiting factor in photochemical ozone formation for large areas in the PRD. For source apportioning of NMHCs as well as ozone pollution control strategies, it is necessary to obtain typical seasonal and diurnal patterns of NMHCs with a large pool of field data. To date, few studies have focused on seasonal and diurnal variations of NMHCs in urban areas of Guangzhou. This study explored the seasonal variations of most hydrocarbons concentrations with autumn maximum and spring minimum in Guangzhou. The diurnal variations of most anthropogenic NMHCs typically showed two-peak pattern with one at 8:00 in the morning and another at 20:00 in the evening, both corresponding to traffic rush hours in Guangzhou, whereas isoprene displayed a different bimodal diurnal curve. Propene, ethene, m, p-xylene and toluene were the four largest contributors to ozone formation in Guangzhou, based on the evaluation of individual NMHCs’ photochemical reactivity. Therefore, an effective strategy for controlling ozone pollution may be achieved by the reduction of vehicle emissions in Guangzhou.

  20. Seasonal and spatial variation in broadleaf forest model parameters

    Science.gov (United States)

    Groenendijk, M.; van der Molen, M. K.; Dolman, A. J.

    2009-04-01

    Process based, coupled ecosystem carbon, energy and water cycle models are used with the ultimate goal to project the effect of future climate change on the terrestrial carbon cycle. A typical dilemma in such exercises is how much detail the model must be given to describe the observations reasonably realistic while also be general. We use a simple vegetation model (5PM) with five model parameters to study the variability of the parameters. These parameters are derived from the observed carbon and water fluxes from the FLUXNET database. For 15 broadleaf forests the model parameters were derived for different time resolutions. It appears that in general for all forests, the correlation coefficient between observed and simulated carbon and water fluxes improves with a higher parameter time resolution. The quality of the simulations is thus always better when a higher time resolution is used. These results show that annual parameters are not capable of properly describing weather effects on ecosystem fluxes, and that two day time resolution yields the best results. A first indication of the climate constraints can be found by the seasonal variation of the covariance between Jm, which describes the maximum electron transport for photosynthesis, and climate variables. A general seasonality we found is that during winter the covariance with all climate variables is zero. Jm increases rapidly after initial spring warming, resulting in a large covariance with air temperature and global radiation. During summer Jm is less variable, but co-varies negatively with air temperature and vapour pressure deficit and positively with soil water content. A temperature response appears during spring and autumn for broadleaf forests. This shows that an annual model parameter cannot be representative for the entire year. And relations with mean annual temperature are not possible. During summer the photosynthesis parameters are constrained by water availability, soil water content and

  1. seasonal variation of intestinal parasitic infections among hiv ...

    African Journals Online (AJOL)

    Abrham

    CONCLUSION: Cryptosporidium species and Strongyloides stercoralis were the only parasitic agents that were associated with rainy season. Keywords: Season, Intestinal Parasites, HIV. INTRODUCTION. Despite the worldwide efforts at controlling the menace of acquired immunodeficiency syndrome. (AIDS), the number ...

  2. Diversity and seasonal variation of zooplankton of Lake Hlan ...

    African Journals Online (AJOL)

    SARAH

    2016-06-30

    Jun 30, 2016 ... The taxonomic composition and the species ... Keywords: Biodiversity; Community structure; Hydrological season; Zooplankton .... Table 1: Seasonal change in recorded environmental parameters ..... reproduction, growth and life duration (Fernandez de .... Spatial temporal patterns and relationships with.

  3. Seasonal variations of agar extracted from different life stages of ...

    African Journals Online (AJOL)

    Seasonality in yield, physical and chemical properties of the native agar from different life stages of Gracilaria cliftonii was investigated over a period of six seasons (autumn 2008–winter 2009). Agar yield and its properties varied as a function of seasons and life stages but there was no significant correlation between ...

  4. Seasonal variation in child mortality in rural Guinea-Bissau

    DEFF Research Database (Denmark)

    Nielsen, Bibi Uhre; Byberg, Stine; Aaby, Peter

    2017-01-01

    Objectives: In many African countries, child mortality is higher in the rainy season than in the dry season. We investigated the effect of season on child mortality by time periods, sex and age in rural Guinea-Bissau. Methods: Bandim health project follows children under-five in a health...

  5. Seasonal Variations of Some Physico-Chemical Properties of River ...

    African Journals Online (AJOL)

    The influence of seasonal changes on the properties of water from Ethiope River at Abraka was investigated. Composite samples from six different sampling points were collected and assessed for both dry and wet seasons. The sampling points represent the villages within Abraka clan along the river. The seasonal ...

  6. Seasonal variation in child mortality in rural Guinea-Bissau.

    Science.gov (United States)

    Nielsen, Bibi Uhre; Byberg, Stine; Aaby, Peter; Rodrigues, Amabelia; Benn, Christine Stabell; Fisker, Ane Baerent

    2017-07-01

    In many African countries, child mortality is higher in the rainy season than in the dry season. We investigated the effect of season on child mortality by time periods, sex and age in rural Guinea-Bissau. Bandim health project follows children under-five in a health and demographic surveillance system in rural Guinea-Bissau. We compared the mortality in the rainy season (June to November) between 1990 and 2013 with the mortality in the dry season (December to May) in Cox proportional hazards models providing rainy vs. dry season mortality rate ratios (r/d-mrr). Seasonal effects were estimated in strata defined by time periods with different frequency of vaccination campaigns, sex and age (<1 month, 1-11 months, 12-59 months). Verbal autopsies were interpreted using InterVa-4 software. From 1990 to 2013, overall mortality was declined by almost two-thirds among 81 292 children (10 588 deaths). Mortality was 51% (95% ci: 45-58%) higher in the rainy season than in the dry season throughout the study period. The seasonal difference increased significantly with age, the r/d-mrr being 0.94 (0.86-1.03) among neonates, 1.57 (1.46-1.69) in post-neonatal infants and 1.83 (1.72-1.95) in under-five children (P for same effect <0.001). According to the InterVa, malaria deaths were the main reason for the seasonal mortality difference, causing 50% of all deaths in the rainy season, but only if the InterVa included season of death, making the argument self-confirmatory. The mortality declined throughout the study, yet rainy season continued to be associated with 51% higher overall mortality. © 2017 The Authors. Tropical Medicine & International Health Published by John Wiley & Sons Ltd.

  7. Seasonal variation of air kerma in the 'Vulcano Porto' area (Aeolian Islands, Italy)

    Energy Technology Data Exchange (ETDEWEB)

    Bellia, S.; Basile, S.; Brai, M. E-mail: mbrai@unipa.it; Hauser, S.; Puccio, P.; Rizzo, S

    2001-02-01

    Air kerma was measured in the 'Vulcano Porto' area of the Vulcano Island, belonging to the Aeolian Islands, in the Mediterranean Sea. Measurements were carried out using thermoluminescence dosimeters. The relationship between observed dose values and source lithology has been assessed. Data show a seasonal variation due to weather conditions but also probably related to features of the soils, making the variation more evident.

  8. Seasonality Affects the Diversity and Composition of Bacterioplankton Communities in Dongjiang River, a Drinking Water Source of Hong Kong

    Directory of Open Access Journals (Sweden)

    Wei Sun

    2017-08-01

    Full Text Available Water quality ranks the most vital criterion for rivers serving as drinking water sources, which periodically changes over seasons. Such fluctuation is believed associated with the state shifts of bacterial community within. To date, seasonality effects on bacterioplankton community patterns in large rivers serving as drinking water sources however, are still poorly understood. Here we investigated the intra-annual bacterial community structure in the Dongjiang River, a drinking water source of Hong Kong, using high-throughput pyrosequencing in concert with geochemical property measurements during dry, and wet seasons. Our results showed that Proteobacteria, Actinobacteria, and Bacteroidetes were the dominant phyla of bacterioplankton communities, which varied in composition, and distribution from dry to wet seasons, and exhibited profound seasonal changes. Actinobacteria, Bacteroidetes, and Cyanobacteria seemed to be more associated with seasonality that the relative abundances of Actinobacteria, and Bacteroidetes were significantly higher in the dry season than those in the wet season (p < 0.01, while the relative abundance of Cyanobacteria was about 10-fold higher in the wet season than in the dry season. Temperature and NO3--N concentration represented key contributing factors to the observed seasonal variations. These findings help understand the roles of various bacterioplankton and their interactions with the biogeochemical processes in the river ecosystem.

  9. Seasonal variations of seismicity and geodetic strain in the Himalaya induced by surface hydrology

    OpenAIRE

    Bettinelli, Pierre; Avouac, Jean-Philippe; Flouzat, Mireille; Bollinger, Laurent; Ramillien, Guillaume; Rajaure, Sudhir; Sapkota, Som

    2008-01-01

    One way to probe earthquake nucleation processes and the relation between stress buildup and seismicity is to analyze the sensitivity of seismicity to stress perturbations. Here, we report evidence for seasonal strain and stress (~ 2–4 kPa) variations in the Nepal Himalaya, induced by water storage variations which correlate with seasonal variations of seismicity. The seismicity rate is twice as high in the winter as in the summer, and correlates with stress rate variations. We infer ~ 10–20 ...

  10. Sources of Variation in Creep Testing

    Science.gov (United States)

    Loewenthal, William S.; Ellis, David L.

    2011-01-01

    Creep rupture is an important material characteristic for the design of rocket engines. It was observed during the characterization of GRCop-84 that the complete data set had nearly 4 orders of magnitude of scatter. This scatter likely confounded attempts to determine how creep performance was influenced by manufacturing. It was unclear if this variation was from the testing, the material, or both. Sources of variation were examined by conducting tests on identically processed specimens at the same specified stresses and temperatures. Significant differences existed between the five constant-load creep frames. The specimen temperature was higher than the desired temperature by as much as 43 C. It was also observed that the temperature gradient was up to 44 C. Improved specimen temperature control minimized temperature variations. The data from additional tests demonstrated that the results from all five frames were comparable. The variation decreased to 1/2 order of magnitude from 2 orders of magnitude for the baseline data set. Independent determination of creep rates in a reference load frame closely matched the creep rates determined after the modifications. Testing in helium tended to decrease the sample temperature gradient, but helium was not a significant improvement over vacuum.

  11. Seasonal Variation in Fluoride Content in Groundwaters of Langtang Area, Northcentral Nigeria

    Science.gov (United States)

    Dibal, H. U.; Dajilak, W. N.; Lekmang, I. C.; Nimze, L. W.; Yenne, E. Y.

    2017-06-01

    Thirty groundwater samples were collected at the peak of the rainy season and analysed for fluoride and other cations and anions in drinking water sources of Langtang area. For comparative purposes, thirty seven groundwater samples were collected in the dry season. The aim of the study was to determine variation in fluoride content with respect to the seasons. Fluoride in water was determined by the Ion Selective Electrode (ISE) and the cations by the Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). The anion (sulphate) was determined by Multi - Ion Colorimeter, bicarbonate and chloride by titration method. In addition fluorine content in aquifer materials from a borehole section were determined by Fusion method. The two seasons show variation in content of fluoride in groundwater. Fluoride content in groundwater is higher in the dry season ranging from 0.13 - 10.3 mg/l compared to the 0.06 - 4.60 mg/l values in the rainy season. Content of fluorine (0.01 wt %) in the aquifer materials (sands) is low from depth of 0 to 7.95 m. However, fluorine content increases with depth, from 7.95 to 10.60 m with concentration of 0.04 wt %, 0.05 wt % from 10.60 to 13.25m, and 0.07 wt % from 13.25 to 15.70 m, the content of fluorine however, decreased at depth 15.70 to18.55m with concentration of 0.02 wt % even with fluorite mineral in the aquifer material at this depth. Dilution of fluoride ion as a result of rain input which recharges the aquifer may be the main reason for lower values recorded in the rainy season. Over fifty and sixty percent of waters in both dry and rainy season have fluoride concentration above the WHO upper limit of 1.5 mg/l. Consumption of these elevated values of fluoride in groundwater of the study area, clearly manifests as symptoms of dental fluorosis.

  12. Seasonal Variation in Fluoride Content in Groundwaters of Langtang Area, Northcentral Nigeria

    Directory of Open Access Journals (Sweden)

    Dibal H.U.

    2017-06-01

    Full Text Available Thirty groundwater samples were collected at the peak of the rainy season and analysed for fluoride and other cations and anions in drinking water sources of Langtang area. For comparative purposes, thirty seven groundwater samples were collected in the dry season. The aim of the study was to determine variation in fluoride content with respect to the seasons. Fluoride in water was determined by the Ion Selective Electrode (ISE and the cations by the Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES. The anion (sulphate was determined by Multi – Ion Colorimeter, bicarbonate and chloride by titration method. In addition fluorine content in aquifer materials from a borehole section were determined by Fusion method. The two seasons show variation in content of fluoride in groundwater. Fluoride content in groundwater is higher in the dry season ranging from 0.13 – 10.3 mg/l compared to the 0.06 – 4.60 mg/l values in the rainy season. Content of fluorine (0.01 wt % in the aquifer materials (sands is low from depth of 0 to 7.95 m. However, fluorine content increases with depth, from 7.95 to 10.60 m with concentration of 0.04 wt %, 0.05 wt % from 10.60 to 13.25m, and 0.07 wt % from 13.25 to 15.70 m, the content of fluorine however, decreased at depth 15.70 to18.55m with concentration of 0.02 wt % even with fluorite mineral in the aquifer material at this depth. Dilution of fluoride ion as a result of rain input which recharges the aquifer may be the main reason for lower values recorded in the rainy season. Over fifty and sixty percent of waters in both dry and rainy season have fluoride concentration above the WHO upper limit of 1.5 mg/l. Consumption of these elevated values of fluoride in groundwater of the study area, clearly manifests as symptoms of dental fluorosis.

  13. Seasonal variations of ochreous precipitates in mine effluents in Finland

    International Nuclear Information System (INIS)

    Kumpulainen, Sirpa; Carlson, Liisa; Raeisaenen, Marja-Liisa

    2007-01-01

    Ochreous precipitate and water samples were collected from the surroundings of seven closed sulphide mines in Finland. In the Hammaslahti Zn-Cu-Au mine, Otravaara pyrite mine and Paroistenjaervi Cu-W-As mine, the collection was repeated in different seasons to study mineralogical and geochemical variations of precipitates. The sampling was done in 1999-2002 from the ditches and drainage ponds of the tailings and waste rock piles that are susceptible to seasonal changes. Mineralogy of the precipitates was evaluated by X-ray diffraction (XRD) and infrared spectroscopy (IR), and precipitate geochemistry was examined by selective extractions. Schwertmannite (Fe 8 O 8 (OH) 6 SO 4 ) was the most typical Fe hydroxide mineral found. Goethite was almost as common as schwertmannite, was often poorly ordered, and contained up to 10 wt.% of SO 4 . Goethite and schwertmannite were commonly found as mixtures, and they occurred in similar pH and SO 4 concentrations. Ferrihydrite (nominally Fe 5 HO 8 . 4H 2 O) was typically found in areas not influenced by acid mine drainage, and also in acid mine waters with high organic matter or As content. Jarosite (KFe 3 (SO 4 ) 2 (OH) 6 ) was found only in one site. In addition, some gypsum (CaSO 4 . 2H 2 O) and aluminous sulphate precipitates (presumably basaluminite, Al 4 (SO 4 )(OH) 10 . 5H 2 O) were identified. Selective extractions showed that acid extracts Fe tot /S tot -ratios of schwertmannite and goethite samples were similar, but the ratio of oxalate-extractable to total Fe, Fe ox /Fe tot , of goethite samples were lower than those of the schwertmannite samples. Only Al, Si and As were bound to precipitates in substantial amounts, up to several wt.%. In schwertmannites and goethites, Al, Cu, Co, Mn and Zn were mostly structural, substituting for Fe in an Fe oxyhydroxide structure or bound to surface adsorption sites in pores limited by diffusion. In ferrihydrites, heavy metals were also partly bound in adsorbed form dissolving in

  14. Seasonal Variation of Harbor Seal's Diet from the Wadden Sea in Relation to Prey Availability.

    Directory of Open Access Journals (Sweden)

    Camille de la Vega

    Full Text Available The Wadden Sea has an important role for marine mammals in terms of resting, nursing and foraging. Harbor seal is the most abundant marine mammal species in this area. The use of the food resources of the Wadden Sea by seals is not clear, and previous studies showed that this species can travel kilometers away from their haul-outs to forage in the North Sea. In this study, we analyzed the stable isotopes of vibrissae from 23 dead harbor seals found on the island of Sylt to investigate their diet. The predator´s carbon and nitrogen isotope compositions were compared to the compositions of different potential prey items from the Sylt-Rømø Bight and from the North Sea in order to study seasonal pattern in the diet and in the foraging location. In parallel, seasonal variation of abundance and biomass of the potential prey items from the Sylt-Rømø Bight were studied and compare to their contribution to the seal´s diet. The results revealed a change in the seal´s diet from pelagic sources in spring to a benthic based diet in summer, and an increasing use of the North Sea resources in fall and winter in accordance with the seasonal variation of the availability of prey in the Sylt-Rømø Bight.

  15. Seasonal and Spatial Variations of Indoor Pollen in a Hospital

    Directory of Open Access Journals (Sweden)

    Santiago Fernández-Rodríguez

    2009-12-01

    Full Text Available The airborne indoor pollen in a hospital of Badajoz (Spain was monitored over two years using a personal Burkard sampler. The air was sampled in four places indoors—one closed room and one open ward on each of the ground and the third floors—and one place outdoors at the entrance to the hospital. The results were compared with data from a continuous volumetric sampler. While 32 pollen types were identified, nearly 75% of the total counts were represented by just five of them. These were: Quercus, Cupressaceae, Poaceae, Olea, and Plantago. The average indoor concentration was 25.2 grains/m3, and the average indoor/outdoor ratio was 0.27. A strong seasonal pattern was found, with the highest levels in spring and winter, and the indoor concentrations were correlated with the outdoor one. Indoor air movement led to great homogeneity in the airborne pollen presence: the indoor results were not influenced by whether or not the room was isolated, the floor level, or the number of people in or transiting the site during sampling. The presence of ornamental vegetation in the area surrounding the building affected the indoor counts directly as sources of the pollen.

  16. Seasonal variation in carbon dioxide exchange over a Mediterranean annual grassland in California

    Energy Technology Data Exchange (ETDEWEB)

    Xu, L; Baldocchi, D

    2004-05-01

    Understanding how environmental variables affect the processes that regulate the carbon flux over grassland is critical for large-scale modeling research, since grasslands comprise almost one-third of the earth's natural vegetation. To address this issue, fluxes of CO{sub 2} (F{sub c}, flux toward the surface is negative) were measured over a Mediterranean, annual grassland in California, USA for 2 years with the eddy covariance method. To interpret the biotic and abiotic factors that modulate F{sub c} over the course of a year we decomposed net ecosystem CO{sub 2} exchange into its constituent components, ecosystem respiration (R{sub eco}) and gross primary production (GPP). Daytime R{sub eco} was extrapolated from the relationship between temperature and nighttime F{sub c} under high turbulent conditions. Then, GPP was estimated by subtracting daytime values of F{sub c} from daytime estimates of R{sub eco}. Results show that most of carbon exchange, both photosynthesis and respiration, was limited to the wet season (typically from October to mid-May). Seasonal variations in GPP followed closely to changes in leaf area index, which in turn was governed by soil moisture, available sunlight and the timing of the last frost. In general, R{sub eco} was an exponential function of soil temperature, but with season-dependent values of Q{sub 10}. The temperature-dependent respiration model failed immediately after rain events, when large pulses of R{sub eco} were observed. Respiration pulses were especially notable during the dry season when the grass was dead and were the consequence of quickly stimulated microbial activity. Integrated values of GPP, R{sub eco}, and net ecosystem exchange (NEE) were 867, 735, and -132g C m{sup -2}, respectively, for the 2000-2001 season, and 729, 758, and 29g C m{sup -2} for the 2001-2002 season. Thus, the grassland was a moderate carbon sink during the first season and a weak carbon source during the second season. In contrast to a

  17. Seasonal variation of physicochemical factor and fecal pollution in the Hansan-Geojeman area, Korea

    Directory of Open Access Journals (Sweden)

    Young Cheol Park

    2016-06-01

    Full Text Available Abstract The seasonal variation of fecal coliforms (FCs and physicochemical factors was determined in seawaters of the Hansan-Geojeman area, including a designated area for oyster, and in inland pollution sources of its drainage basin. The mean daily loads of FCs in inland pollution sources ranged from 1.2 × 109 to 3.1 × 1011 most probable number (MPN/day; however, the pollutants could not be reached at the designated area. FC concentrations of seawaters were closely related to season, rainfall, and inland contaminants, however, within the regulation limit of various countries for shellfish. The highest concentrations for chemical oxygen demand (COD and chlorophyll-a in seawaters were shown in the surface layer during August with high rainfall, whereas the lowest for dissolved oxygen (DO in the bottom layer of the same month. Therefore, it indicates that the concentrations of FC, COD, DO, and chlorophyll-a of seawaters were closely related to season and rainfall.

  18. Seasonal variation of infiltration capacities of soils in western Oregon.

    Science.gov (United States)

    Michael G. Johnson; Robert L. Beschta

    1981-01-01

    Infiltration capacities were 50 percent greater during fall than during summer for forest soils of western Oregon. These results contrast with those measured in other studies. In forested areas, investigators should be aware of potentially large seasonal changes in infiltration capacities. Such seasonal changes may exceed effects due to applied treatments (logging,...

  19. Seasonal variation in diversity and abundance of understorey birds ...

    African Journals Online (AJOL)

    Our findings suggest that in a situation where there is no natural forest, an exotic plantation with suitable indigenous understorey cover can help in protection of birds, including endemic and near-endemic species. Keywords: birds, conservation, Eastern Arc Mountains, plantation, seasonal altitudinal migration, seasons, ...

  20. Seasonal trends, chemical speciation and source apportionment of fine PM in Tehran

    Science.gov (United States)

    Arhami, Mohammad; Hosseini, Vahid; Zare Shahne, Maryam; Bigdeli, Mostafa; Lai, Alexandra; Schauer, James J.

    2017-03-01

    Frequent air pollution episodes have been reported for Tehran, Iran, mainly because of critically high levels of fine particulate matter (PM2.5). The composition and sources of these particles are poorly known, so this study aims to identify the major components and heavy metals in PM2.5 along with their seasonal trends and associated sources. 24-hour PM2.5 samples were collected at a main residential station every 6 days for a full year from February 2014 to February 2015. The samples were analyzed for ions, organic carbon (including water-soluble and insoluble portions), elemental carbon (EC), and all detectable elements. The dominant mass components, which were determined by means of chemical mass closure, were organic matter (35%), dust (25%), non-sea salt sulfate (11%), EC (9%), ammonium (5%), and nitrate (2%). Organic matter and EC together comprised 44% of fine PM on average (increased to >70% in the colder season), which reflects the significance of anthropogenic urban sources (i.e. vehicles). The contributions of different components varied considerably throughout the year, particularly the dust component that varied from 7% in the cold season to 56% in the hot and dry season. Principal component analyses were applied, resulting in 5 major source factors that explained 85% of the variance in fine PM. Factor 1, representing soil dust, explained 53%; Factor 2 denotes heavy metals mainly found in industrial sources and accounted for 18%; and rest of factors, mainly representing combustion sources, explained 14% of the variation. The levels of major heavy metals were further evaluated, and their trends showed considerable increases during cold seasons. The results of this study provide useful insight to fine PM in Tehran, which could help in identifying their health effects and sources, and also adopting effective control strategies.

  1. Seasonal Trophic Shift of Littoral Consumers in Eutrophic Lake Taihu (China Revealed by a Two-Source Mixing Model

    Directory of Open Access Journals (Sweden)

    Qiong Zhou

    2011-01-01

    Full Text Available We evaluated the seasonal variation in the contributions of planktonic and benthic resources to 11 littoral predators in eutrophic Lake Taihu (China from 2004 to 2005. Seasonal fluctuations in consumer σ13C and σ15N were attributed to the combined impacts of temporal variation in isotopic signatures of basal resources and the diet shift of fishes. Based on a two-end-member mixing model, all target consumers relied on energy sources from coupled benthic and planktonic pathways, but the predominant energy source for most species was highly variable across seasons, showing seasonal trophic shift of littoral consumers. Seasonality in energy mobilization of consumers focused on two aspects: (1 the species number of consumers that relied mainly on planktonic carbon showed the lowest values in the fall and the highest during spring/summer, and (2 most consumer species showed seasonal variation in the percentages of planktonic reliance. We concluded that seasonal trophic shifts of fishes and invertebrates were driven by phytoplankton production, but benthic resources were also important seasonally in supporting littoral consumers in Meiliang Bay. Energy mobilization of carnivorous fishes was more subject to the impact of resource availability than omnivorous species.

  2. Seasonal and Spatial Variability of Anthropogenic and Natural Factors Influencing Groundwater Quality Based on Source Apportionment

    Directory of Open Access Journals (Sweden)

    Xueru Guo

    2018-02-01

    Full Text Available Globally, groundwater resources are being deteriorated by rapid social development. Thus, there is an urgent need to assess the combined impacts of natural and enhanced anthropogenic sources on groundwater chemistry. The aim of this study was to identify seasonal characteristics and spatial variations in anthropogenic and natural effects, to improve the understanding of major hydrogeochemical processes based on source apportionment. 34 groundwater points located in a riverside groundwater resource area in northeast China were sampled during the wet and dry seasons in 2015. Using principal component analysis and factor analysis, 4 principal components (PCs were extracted from 16 groundwater parameters. Three of the PCs were water-rock interaction (PC1, geogenic Fe and Mn (PC2, and agricultural pollution (PC3. A remarkable difference (PC4 was organic pollution originating from negative anthropogenic effects during the wet season, and geogenic F enrichment during the dry season. Groundwater exploitation resulted in dramatic depression cone with higher hydraulic gradient around the water source area. It not only intensified dissolution of calcite, dolomite, gypsum, Fe, Mn and fluorine minerals, but also induced more surface water recharge for the water source area. The spatial distribution of the PCs also suggested the center of the study area was extremely vulnerable to contamination by Fe, Mn, COD, and F−.

  3. Investigating the patterns and determinants of seasonal variation in vitamin D status in Australian adults: the Seasonal D Cohort Study

    Directory of Open Access Journals (Sweden)

    Laura King

    2016-08-01

    Full Text Available Abstract Background Vitamin D status generally varies seasonally with changing solar UVB radiation, time in the sun, amount of skin exposed, and, possibly, diet. The Seasonal D Study was designed to quantify the amplitude and phase of seasonal variation in the serum concentration of 25-hydroxyvitamin D, (25OHD and identify the determinants of the amplitude and phase and those of inter-individual variability in seasonal pattern. Methods The Seasonal D Study collected data 2-monthly for 12 months, including demographics, personal sun exposure using a diary and polysulphone dosimeters over 7 days, and blood for serum 25(OHD concentration. The study recruited 333 adults aged 18–79 years living in Canberra (35°S, n = 168 and Brisbane (27°South, n = 165, Australia. Discussion We report the study design and cohort description for the Seasonal D Study. The study has collected a wealth of data to examine inter- and intra-individual seasonal variation in vitamin D status and serum 25(OHD levels in Australian adults.

  4. Seasonal variation of prices of sugar cane, ethanol and electric power

    International Nuclear Information System (INIS)

    Melo, Carmem Ozana de; Silva, Gerson Henrique da; Bueno, Osmar de Carvalho; Esperancini, Maura Seiko Tsutsui

    2010-01-01

    The aim of this study was to assess the seasonal price of sugar cane, fuel alcohol (hydrated and anhydrous) and electricity tariffs as a way of aiding tool for optimization of energy generation, using biomass originating from cane sugar. Using the method of moving average centered was concluded that cane and electricity rates were close to seasonal average, with low range of prices, suggesting the non-occurrence of seasonal variation in prices. Unlike the seasonal indices of ethanol showed seasonal variation of prices with greater amplitude of seasonal index. Thus, the results suggest that the utilization of by-products of sugar cane to produce electrical power points to the prospect of reducing risks associated with variations in the price of ethanol, thereby contributing to greater stability and possibility to those involved in planning alcohol sector. (author)

  5. Seasonal variation in diurnal atmospheric grass pollen concentration profiles

    DEFF Research Database (Denmark)

    Peel, Robert George; Ørby, Pia Viuf; Skjøth, Carsten Ambelas

    2014-01-01

    the time of day when peak concentrations are most likely to occur using seasonally averaged diurnal profiles. Atmospheric pollen loads are highly dependent upon emissions, and different species of grass are known to flower and emit pollen at different times of the day and during different periods......In this study, the diurnal atmospheric grass pollen concentration profile within the Danish city of Aarhus was shown to change in a systematic manner as the pollen season progressed. Although diurnal grass pollen profiles can differ greatly from day-to-day, it is common practice to establish...... of the pollen season. Pollen concentrations are also influenced by meteorological factors - directly through those parameters that govern pollen dispersion and transport, and indirectly through the weather-driven flowering process. We found that three different profiles dominated the grass pollen season...

  6. Seasonal variation of meteorological factors on air parameters and ...

    African Journals Online (AJOL)

    user

    African Journal of Environmental Science and. Technology. Full Length ..... higher volume during dry season and lower volume during rainy .... 224 Afr. J. Environ. Sci. Technol. ..... Procedia - Social and Behavioral Sciences. 1- 5. Babatunde ...

  7. Seasonal variation of imipramine binding in the blood platelets of normal controls and depressed patients

    International Nuclear Information System (INIS)

    Arora, R.C.; Meltzer, H.Y.

    1988-01-01

    Imipramine binding (IB) was studied in the blood platelets from normal controls and depressed patients over a 4-year period (1981-1984) to determine if seasonal variation was present in Bmax or KD. Bimonthly variation in the Bmax of IB was found in normal controls studied longitudinally. No such variation was found when individual values from normal controls were examined on a monthly or seasonal basis. Bmax in depressed patients showed a significant seasonal, but not monthly, variation. KD of IB varied in normal controls using monthly or seasonal data, but not in the probably more reliable bimonthly data. These results suggest that IB studies comparing groups of subjects should match groups for season of the year or, for greater accuracy, month of the year

  8. Seasonal transfer of oxygen isotopes from precipitation and soil to the tree ring: source water versus needle water enrichment.

    Science.gov (United States)

    Treydte, Kerstin; Boda, Sonja; Graf Pannatier, Elisabeth; Fonti, Patrick; Frank, David; Ullrich, Bastian; Saurer, Matthias; Siegwolf, Rolf; Battipaglia, Giovanna; Werner, Willy; Gessler, Arthur

    2014-05-01

    For accurate interpretation of oxygen isotopes in tree rings (δ(18) O), it is necessary to disentangle the mechanisms underlying the variations in the tree's internal water cycle and to understand the transfer of source versus leaf water δ(18) O to phloem sugars and stem wood. We studied the seasonal transfer of oxygen isotopes from precipitation and soil water through the xylem, needles and phloem to the tree rings of Larix decidua at two alpine sites in the Lötschental (Switzerland). Weekly resolved δ(18) O records of precipitation, soil water, xylem and needle water, phloem organic matter and tree rings were developed. Week-to-week variations in needle-water (18) O enrichment were strongly controlled by weather conditions during the growing season. These short-term variations were, however, not significantly fingerprinted in tree-ring δ(18) O. Instead, seasonal trends in tree-ring δ(18) O predominantly mirrored trends in the source water, including recent precipitation and soil water pools. Modelling results support these findings: seasonal tree-ring δ(18) O variations are captured best when the week-to-week variations of the leaf water signal are suppressed. Our results suggest that climate signals in tree-ring δ(18) O variations should be strongest at temperate sites with humid conditions and precipitation maxima during the growing season. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  9. Seasonal temperature variation influences climate suitability for dengue, chikungunya, and Zika transmission.

    Science.gov (United States)

    Huber, John H; Childs, Marissa L; Caldwell, Jamie M; Mordecai, Erin A

    2018-05-01

    Dengue, chikungunya, and Zika virus epidemics transmitted by Aedes aegypti mosquitoes have recently (re)emerged and spread throughout the Americas, Southeast Asia, the Pacific Islands, and elsewhere. Understanding how environmental conditions affect epidemic dynamics is critical for predicting and responding to the geographic and seasonal spread of disease. Specifically, we lack a mechanistic understanding of how seasonal variation in temperature affects epidemic magnitude and duration. Here, we develop a dynamic disease transmission model for dengue virus and Aedes aegypti mosquitoes that integrates mechanistic, empirically parameterized, and independently validated mosquito and virus trait thermal responses under seasonally varying temperatures. We examine the influence of seasonal temperature mean, variation, and temperature at the start of the epidemic on disease dynamics. We find that at both constant and seasonally varying temperatures, warmer temperatures at the start of epidemics promote more rapid epidemics due to faster burnout of the susceptible population. By contrast, intermediate temperatures (24-25°C) at epidemic onset produced the largest epidemics in both constant and seasonally varying temperature regimes. When seasonal temperature variation was low, 25-35°C annual average temperatures produced the largest epidemics, but this range shifted to cooler temperatures as seasonal temperature variation increased (analogous to previous results for diurnal temperature variation). Tropical and sub-tropical cities such as Rio de Janeiro, Fortaleza, and Salvador, Brazil; Cali, Cartagena, and Barranquilla, Colombia; Delhi, India; Guangzhou, China; and Manila, Philippines have mean annual temperatures and seasonal temperature ranges that produced the largest epidemics. However, more temperate cities like Shanghai, China had high epidemic suitability because large seasonal variation offset moderate annual average temperatures. By accounting for seasonal

  10. Seasonal temperature variation influences climate suitability for dengue, chikungunya, and Zika transmission.

    Directory of Open Access Journals (Sweden)

    John H Huber

    2018-05-01

    Full Text Available Dengue, chikungunya, and Zika virus epidemics transmitted by Aedes aegypti mosquitoes have recently (reemerged and spread throughout the Americas, Southeast Asia, the Pacific Islands, and elsewhere. Understanding how environmental conditions affect epidemic dynamics is critical for predicting and responding to the geographic and seasonal spread of disease. Specifically, we lack a mechanistic understanding of how seasonal variation in temperature affects epidemic magnitude and duration. Here, we develop a dynamic disease transmission model for dengue virus and Aedes aegypti mosquitoes that integrates mechanistic, empirically parameterized, and independently validated mosquito and virus trait thermal responses under seasonally varying temperatures. We examine the influence of seasonal temperature mean, variation, and temperature at the start of the epidemic on disease dynamics. We find that at both constant and seasonally varying temperatures, warmer temperatures at the start of epidemics promote more rapid epidemics due to faster burnout of the susceptible population. By contrast, intermediate temperatures (24-25°C at epidemic onset produced the largest epidemics in both constant and seasonally varying temperature regimes. When seasonal temperature variation was low, 25-35°C annual average temperatures produced the largest epidemics, but this range shifted to cooler temperatures as seasonal temperature variation increased (analogous to previous results for diurnal temperature variation. Tropical and sub-tropical cities such as Rio de Janeiro, Fortaleza, and Salvador, Brazil; Cali, Cartagena, and Barranquilla, Colombia; Delhi, India; Guangzhou, China; and Manila, Philippines have mean annual temperatures and seasonal temperature ranges that produced the largest epidemics. However, more temperate cities like Shanghai, China had high epidemic suitability because large seasonal variation offset moderate annual average temperatures. By accounting

  11. Seasonal variations of nitrogen and phosphorus retention in an agricultural drainage river in East China.

    Science.gov (United States)

    Chen, Dingjiang; Lu, Jun; Wang, Hailong; Shen, Yena; Kimberley, Mark O

    2010-02-01

    Riverine retention decreases loads of nitrogen (N) and phosphorus (P) in running water. It is an important process in nutrient cycling in watersheds. However, temporal riverine nutrient retention capacity varies due to changes in hydrological, ecological, and nutrient inputs into the watershed. Quantitative information of seasonal riverine N and P retention is critical for developing strategies to combat diffuse source pollution and eutrophication in riverine and coastal systems. This study examined seasonal variation of riverine total N (TN) and total P (TP) retention in the ChangLe River, an agricultural drainage river in east China. Water quality, hydrological parameters, and hydrophyte coverage were monitored along the ChangLe River monthly during 2004-2006. Nutrient export loads (including chemical fertilizer, livestock, and domestic sources) entering the river from the catchment area were computed using an export coefficient model based on estimated nutrient sources. Riverine TN and TP retention loads (RNRL and RPRL) were estimated using mass balance calculations. Temporal variations in riverine nutrient retention were analyzed statistically. Estimated annual riverine retention loads ranged from 1,538 to 2,127 t year(-1) for RNRL and from 79.4 to 90.4 t year(-1) for RPRL. Monthly retention loads varied from 6.4 to 300.8 t month(-1) for RNRL and from 1.4 to 15.3 t month(-1) for RPRL. Both RNRL and RPRL increased with river flow, water temperature, hydrophyte coverage, monthly sunshine hours, and total TN and TP inputs. Dissolved oxygen concentration and the pH level of the river water decreased with RNRL and RPRL. Riverine nutrient retention ratios (retention as a percentage of total input) were only related to hydrophyte coverage and monthly sunshine hours. Monthly variations in RNRL and RPRL were functions of TN and TP loads. Riverine nutrient retention capacity varied with environmental conditions. Annual RNRL and RPRL accounted for 30.3-48.3% and 52

  12. Seasonal variation of ground spiders in a Brazilian Savanna

    Directory of Open Access Journals (Sweden)

    Marina Farcic Mineo

    2010-06-01

    Full Text Available The Brazilian Savanna Ecoregion (Cerrado is one of the richest biomes in the world, with a characteristic highly seasonal climate a dry season between May and September and a rainy season from October through April. Ground-dwelling spiders from three Cerrado phytophysiognomies, "campo cerrado", "cerrado" and "cerrad��o", were sampled using pitfall traps during two years, totaling 111 species and 3,529 individuals. The abundance of individuals and species richness was higher during the wet season. Fifty-eight species were captured exclusively during that period, whereas only nineteen were restricted to the dry season. Only two species were found in all samples. The number of juveniles was higher than the number of adults in all phytophysiognomies and in all species during both seasons. The highest abundance was registered in October and the lowest in April. Overall sex ratio was male-biased in all vegetation types sampled. Distinct climate variables affected the abundance of spiders depending on sex, age and vegetal physiognomy where they were sampled. This study involved the longest sampling of spider abundance and diversity on the ground of a Brazilian Savanna.

  13. Seasonal variation and light absorption property of carbonaceous aerosol in a typical glacier region of the southeastern Tibetan Plateau

    Science.gov (United States)

    Niu, Hewen; Kang, Shichang; Wang, Hailong; Zhang, Rudong; Lu, Xixi; Qian, Yun; Paudyal, Rukumesh; Wang, Shijin; Shi, Xiaofei; Yan, Xingguo

    2018-05-01

    Deposition and accumulation of light-absorbing carbonaceous aerosol on glacier surfaces can alter the energy balance of glaciers. In this study, 2 years (December 2014 to December 2016) of continuous observations of carbonaceous aerosols in the glacierized region of the Mt. Yulong and Ganhaizi (GHZ) basin are analyzed. The average elemental carbon (EC) and organic carbon (OC) concentrations were 1.51±0.93 and 2.57±1.32 µg m-3, respectively. Although the annual mean OC / EC ratio was 2.45±1.96, monthly mean EC concentrations during the post-monsoon season were even higher than OC in the high altitudes (approximately 5000 m a. s. l. ) of Mt. Yulong. Strong photochemical reactions and local tourism activities were likely the main factors inducing high OC / EC ratios in the Mt. Yulong region during the monsoon season. The mean mass absorption efficiency (MAE) of EC, measured for the first time in Mt. Yulong, at 632 nm with a thermal-optical carbon analyzer using the filter-based method, was 6.82±0.73 m2 g-1, comparable with the results from other studies. Strong seasonal and spatial variations of EC MAE were largely related to the OC abundance. Source attribution analysis using a global aerosol-climate model, equipped with a black carbon (BC) source tagging technique, suggests that East Asia emissions, including local sources, have the dominant contribution (over 50 %) to annual mean near-surface BC in the Mt. Yulong area. There is also a strong seasonal variation in the regional source apportionment. South Asia has the largest contribution to near-surface BC during the pre-monsoon season, while East Asia dominates the monsoon season and post-monsoon season. Results in this study have great implications for accurately evaluating the influences of carbonaceous matter on glacial melting and water resource supply in glacierization areas.

  14. Seasonal variation in the input of atmospheric selenium to northwestern Greenland snow

    International Nuclear Information System (INIS)

    Lee, Khanghyun; Hong, Sang-Bum; Lee, Jeonghoon; Chung, Jiwoong; Hur, Soon-Do; Hong, Sungmin

    2015-01-01

    Oxygen isotope ratio (δ 18 O) and concentrations of Al, Na + , methanesulfonic acid (MSA), SO 4 2− , and selenium (Se) in a continuous series of 70 snow samples from a 3.2-m snow pit at a site in northwestern Greenland were determined using ultraclean procedures. Well-defined depth profiles of δ 18 O, Al, and sea-salt-Na + allowed the determination of chronology of the snow pit that spanned approximately 6 years from spring 2003 to summer 2009. Se concentrations were at a low pg/g level, ranging from 7.2 to 45 pg/g, and exhibited high variability with generally higher values during winter and spring and lower values during summer and fall. Very high crustal enrichment factors (EF c ) of Se averaging approximately 26,600 for the entire time period indicate a small contribution from crust dust. High Se/MSA ratios are generally observed in the winter and spring snow layers, in which the Se concentrations were relatively high (> 20 pg/g). This suggests that a significant component of the Se present in the snow layers is of anthropogenic origin. During the summer season, however, high EF c values are accompanied with low Se/MSA, indicating an increased contribution of marine biogenic sources. Significant correlations between Se, Al, and non-sea-salt SO 4 2− highlight that significant inputs of Se to the snow are likely controlled by the seasonality in the transport efficiency of anthropogenic Se from the source regions to the site. Based on the seasonal changes in Se concentrations, Se/MSA, and Se/S ratios observed in the samples, the input of anthropogenic Se to the site appears to be governed by the long-range transportation of Se emitted from coal combustion in East Asian countries, especially in China. - Highlights: • The first comprehensive seasonal variation of Se in Greenland snow is presented. • Data exhibit pronounced seasonality in the fallout of Se to Greenland. • High Se/MSA ratios indicate a significant contribution from anthropogenic sources.

  15. Seasonal variation in the input of atmospheric selenium to northwestern Greenland snow

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Khanghyun; Hong, Sang-Bum [Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon 406–840 (Korea, Republic of); Lee, Jeonghoon [Department of Science Education, Ewha womans University, 52 Ewhayeodae-gil, Seodaemun-gu, Seoul 120-750 (Korea, Republic of); Chung, Jiwoong; Hur, Soon-Do [Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon 406–840 (Korea, Republic of); Hong, Sungmin, E-mail: smhong@inha.ac.kr [Department of Ocean Sciences, Inha University, 100 Inharo, Nam-gu, Incheon 402-751 (Korea, Republic of)

    2015-09-01

    Oxygen isotope ratio (δ{sup 18}O) and concentrations of Al, Na{sup +}, methanesulfonic acid (MSA), SO{sub 4}{sup 2−}, and selenium (Se) in a continuous series of 70 snow samples from a 3.2-m snow pit at a site in northwestern Greenland were determined using ultraclean procedures. Well-defined depth profiles of δ{sup 18}O, Al, and sea-salt-Na{sup +} allowed the determination of chronology of the snow pit that spanned approximately 6 years from spring 2003 to summer 2009. Se concentrations were at a low pg/g level, ranging from 7.2 to 45 pg/g, and exhibited high variability with generally higher values during winter and spring and lower values during summer and fall. Very high crustal enrichment factors (EF{sub c}) of Se averaging approximately 26,600 for the entire time period indicate a small contribution from crust dust. High Se/MSA ratios are generally observed in the winter and spring snow layers, in which the Se concentrations were relatively high (> 20 pg/g). This suggests that a significant component of the Se present in the snow layers is of anthropogenic origin. During the summer season, however, high EF{sub c} values are accompanied with low Se/MSA, indicating an increased contribution of marine biogenic sources. Significant correlations between Se, Al, and non-sea-salt SO{sub 4}{sup 2−} highlight that significant inputs of Se to the snow are likely controlled by the seasonality in the transport efficiency of anthropogenic Se from the source regions to the site. Based on the seasonal changes in Se concentrations, Se/MSA, and Se/S ratios observed in the samples, the input of anthropogenic Se to the site appears to be governed by the long-range transportation of Se emitted from coal combustion in East Asian countries, especially in China. - Highlights: • The first comprehensive seasonal variation of Se in Greenland snow is presented. • Data exhibit pronounced seasonality in the fallout of Se to Greenland. • High Se/MSA ratios indicate a

  16. Seasonal inter-relationships in atmospheric methane and companion delta13C values: effects of sinks and sources

    Energy Technology Data Exchange (ETDEWEB)

    Lassey, K. R.; Mikaloff Fletcher, S. E. (NIWA, Wellington (New Zealand)), e-mail: k.lassey@niwa.co.nz; Allan, W. (Allan Planning and Research Ltd., Petone (New Zealand))

    2011-07-15

    Recent developments in applying carbon-isotope information to better understand regional and global methane budgets infer a strong role by a highly fractionating seasonal sink such as atomic chlorine. Specifically, OH as the predominant seasonal sink cannot account for the 'phase ellipses' based on observed seasonal cycles of methane mixing ratio and isotope ratio, delta13C. Although a strong role by atomic chlorine is inferred empirically, open questions remain about the interplay between sources and sinks in determining the properties of phase ellipses. This paper employs a simple didactic model of the seasonal cycling of atmospheric methane to understand such interplay. We demonstrate that a single seasonal sink and seasonal source act together to imprint anti-phase seasonalities on atmospheric methane and delta13C, which lead to phase ellipses that collapse onto a straight line with slope characteristic of that sink. This explains empirical findings of these anti-phase relationships in three-dimensional modelling studies. We also demonstrate that multiple seasonal sinks acting with a seasonal source can yield surprising properties for the phase ellipse that not only explain some features of phase ellipses reported in modelling studies but also have the potential to explain marked inter-annual variation in phase ellipses based on observation

  17. Seasonal variation of mood and behaviour in a healthy middle-aged population in Japan.

    Science.gov (United States)

    Okawa, M; Shirakawa, S; Uchiyama, M; Oguri, M; Kohsaka, M; Mishima, K; Sakamoto, K; Inoue, H; Kamei, K; Takahashi, K

    1996-10-01

    A population survey of seasonality in six representative cities in Japan was conducted using the Japanese version of the Seasonal Pattern Assessment Questionnaire (SPAQ). The questionnaires were given to 951 parents (male: female ratio 1:1 age range 34-59 years) of high-school students. Significant regional differences in seasonal variations of mood, length of sleep, and weight were observed; the proportion of individuals reporting high seasonality in the two northern cities was significantly higher than that in the other areas. These results provide evidence for a northern predominance in the prevalence of seasonal affective disorder in Japan.

  18. Seasonal variations in health-related human physical activity.

    Science.gov (United States)

    Reilly, Thomas; Peiser, Benny

    2006-01-01

    There are profound fluctuations in climate that occur within the annual cycle of seasonal changes. The severity of these changes depends on latitude of location and prevailing topography. Living creatures have evolved means of coping with seasonal extremes. Endogenous circannual cycles, at least in humans, appear to have been masked by mechanisms employed to cope with environmental changes. Physical activity levels tend to be lower in winter than in summer, mediating effects on health-related fitness. In athletes, seasonal changes are dictated by requirements of the annual programme of competitive engagements rather than an inherent circannual rhythm. Injury rates are influenced by seasonal environmental factors, notably in field sports. Season of birth has been related to susceptibility to selected morbidities, including mental ill-health. In age-restricted sports, there is a date-of-birth bias favouring those individuals born early in the competitive year. Trainers and selectors should acknowledge this trend if they are to avoid omitting gifted individuals, born later in the year, from talent development programmes.

  19. Seasonal Variations in Mood and Behavior in Romanian Postgraduate Students

    Directory of Open Access Journals (Sweden)

    Joseph J. Soriano

    2007-01-01

    Full Text Available To our knowledge, this paper is the first to estimate seasonality of mood in a predominantly Caucasian sample, living in areas with hot summers and a relative unavailability of air conditioning. As a summer pattern of seasonal depression was previously associated with a vulnerability to heat exposure, we hypothesized that those with access to air conditioners would have a lower rate of summer seasonal affective disorder (SAD compared to those without air conditioning. A convenience sample of 476 Romanian postgraduate students completed the Seasonal Pattern Assessment Questionnaire (SPAQ, which was used to calculate a global seasonality score (GSS and to estimate the rates of winter- and summer-type SAD. The ratio of summer- vs. winter-type SAD was compared using multinomial probability distribution tests. We also compared the ratio of summer SAD in individuals with vs. without air conditioners. Winter SAD and winter subsyndromal SAD (S-SAD were significantly more prevalent than summer SAD and summer S-SAD. Those with access to air conditioners had a higher, rather than a lower, rate of summer SAD. Our results are consistent with prior studies that reported a lower prevalence of summer than winter SAD in Caucasian populations. Finding an increased rate of summer SAD in the minority of those with access to air conditioners was surprising and deserves replication.

  20. Influence of seasonal variation in mood and behavior on cognitive test performance among young adults.

    Science.gov (United States)

    Merikanto, Ilona; Lahti, Tuuli; Castaneda, Anu E; Tuulio-Henriksson, Annamari; Aalto-Setälä, Terhi; Suvisaari, Jaana; Partonen, Timo

    2012-10-01

    Seasonal variations in mood and behavior are common among the general population and may have a deteriorating effect on cognitive functions. In this study the effect of seasonal affective disorder (SAD-like symptoms) on cognitive test performance were evaluated in more detail. The data were derived from the study Mental Health in Early Adulthood in Finland. Participants (n = 481) filled in a modified Seasonal Pattern Assessment Questionnaire (SPAQ) and performed cognitive tests in verbal and visual skills, attention and general intelligence. SAD-like symptoms, especially regarding the seasonal variations in weight and appetite, had a significant effect on working memory (Digit Span Backward, P = 0.008) and auditory attention and short-term memory (Digit Span Forward, P = 0.004). The seasonal variations in sleep duration and mood had an effect on auditory attention and short-term memory (Digit Span Forward, P = 0.02 and P = 0.0002, respectively). The seasonal variations in social activity and energy level had no effect. Seasonal changes in mood, appetite and weight have an impairing effect on auditory attention and processing speed. If performance tests are not to repeated in different seasons, attention needs to be given to the most appropriate season in which to test.

  1. Seasonal Changes in Atmospheric Noise Levels and the Annual Variation in Pigeon Homing Performance

    Science.gov (United States)

    Hagstrum, J. T.; McIsaac, H. P.; Drob, D. P.

    2015-12-01

    The remarkable navigational ability of homing pigeons (Columba livia) is influenced by a number of factors, an unknown one of which causes the "Wintereffekt"1 or annual variation in homing performance. Minima in homeward orientation and return speeds have been observed in winter, with maxima in summer, during repetitive pigeon releases from single sites near experimental lofts in Wilhelmshaven, Göttingen, and Munich, Germany, and near Pisa, Italy1-4. Overall the annual variation is more pronounced in northern Germany than Italy4, and both mature and juvenile cohorts respond to this seasonal factor. Older, more experienced pigeons are better at compensating for its effects than naïve ones, but are still affected after numerous releases. The narrow low-frequency band of atmospheric background noise (microbaroms; 0.1-0.3 Hz) also varies with an annual cycle that generally has higher amplitudes in winter than in summer depending on location5. In addition, homing pigeons, and possibly other birds, apparently use infrasonic signals of similar frequency as navigational cues6, and a seasonal variation in background noise levels could cause corresponding changes in signal-to-noise ratios and thus in homing performance. The annual variation in homing performance, however, was not observed during long-term pigeon releases at two sites in eastern North America. The annual and geographic variability in homing performance in the northern hemisphere can be explained to a first order by seasonal changes in infrasonic noise sources related to ocean storm activity, and to the direction and intensity of stratospheric winds. In addition, increased dispersion in departure bearings of individual birds for some North American releases were likely caused by additional infrasonic noise associated with severe weather events during tornado and Atlantic hurricane seasons. 1Kramer, G. & von Saint Paul, U., J. Ornithol. 97, 353-370 (1956); 2Wallraff, H. G., Z. Tierpsychol. 17, 82-113 (1960

  2. Seasonal and Sexual Variation in Metabolism, Thermoregulation, and Hormones in the Big Brown Bat (Eptesicus fuscus).

    Science.gov (United States)

    Richardson, Christopher S; Heeren, Tim; Kunz, Thomas H

    In response to seasonal variation in energy availability and thermal environment, physiological and endocrine mechanisms have evolved in temperate zone animals. Seasonal changes in hormone activity affect metabolism, body temperature, and reproductive activity. We examined the seasonal regulatory role of hormones on basal metabolic rate (BMR) and regulatory nonshivering thermogenesis (RNST) in 98 female and 17 male adult Eptesicus fuscus (big brown bat). We measured BMR, RNST, and plasma levels of thyroid hormone (T 3 ), leptin, and cortisol in bats captured in maternity colonies in eastern Massachusetts from May to August (from arousal from the hibernation phase to the prehibernation phase). We hypothesized that all three hormones are seasonally primarily metabolic hormones and secondarily thermogenic hormones. In males, only BMR significantly changed seasonally. In females, all five variables significantly changed seasonally. The seasonal pattern of plasma leptin and cortisol levels correlated with the seasonal pattern of BMR, with an initial increase followed by a decrease, suggesting that leptin and cortisol are primarily metabolic hormones. The seasonal pattern of plasma T 3 levels generally paralleled the basic seasonal pattern of RNST, with both increasing at the second half of the season, suggesting that T 3 is primarily a thermogenic hormone. The observed decrease in plasma leptin levels may be necessary to allow for the observed seasonal decrease in BMR, with the similar cortisol pattern important for leptin regulation. While T 3 is needed to maintain BMR, it may play a more critical role in the seasonal regulation of RNST than of BMR.

  3. Seasonal Variation of Atmospheric Composition of Water-Soluble ...

    African Journals Online (AJOL)

    `123456789jkl''''#

    Background Site in Tanzania, East Africa. 1Mkoma S.L. ... fine, coarse and PM10 mass were, 17±4, 52±27 and 69±29 µg/m3 during the 2005 dry season campaign and. 13±5, 34±23 ... particles in ambient air, atmospheric particulate ... especially the fine particle fraction with ..... Atmospheric Chemistry and Physics: From Air.

  4. Seasonal variation of bacterial endophytes in urban trees

    Directory of Open Access Journals (Sweden)

    Shu Yi eShen

    2015-05-01

    Full Text Available Bacterial endophytes, non-pathogenic bacteria residing within plants, contribute to the growth and development of plants and their ability to adapt to adverse conditions. In order to fully exploit the capabilities of these bacteria, it is necessary to understand the extent to which endophytic communities vary between species and over time. The endophytes of Acer negundo, Ulmus pumila and Ulmus parvifolia were sampled over three seasons and analyzed using culture dependent and independent methods (culture on two media, terminal restriction fragment length polymorphism, and tagged pyrosequencing of 16S ribosomal amplicons. The majority of culturable endophytes isolated were Actinobacteria, and all the samples harbored Bacillus, Curtobacterium, Frigoribacterium, Methylobacterium, Paenibacilllus and Sphingomonas species. Regardless of culture medium used, only the culturable communities obtained in the winter for A. negundo could be distinguished from those of Ulmus spp.. In contrast, the nonculturable communities were dominated by Proteobacteria and Actinobacteria, particularly Erwinia, Ralstonia and Sanguibacter spp.. The presence and abundance of various bacterial classes and phyla changed with the changing seasons. Multivariate analysis on the culture independent data revealed significant community differences between the endophytic communities of A. negundo and Ulmus spp., but overall season was the main determinant of endophytic community structure. This study suggests investigations of the studies ofendophytic populations of urban trees should expect to find significant seasonal and species-specific community differences and sampling should proceed accordingly.

  5. Seasonal variation of the salinity in the Zuari estuary, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Shetye, S.R.; Murty, C.S.

    The annual salt budget of the Zuari is examined. The characteristics of the estuary differ markedly from the low run off season during November - May to the heavy run off period of the southwest monsoon from June to October. During November - May...

  6. Variations between post- and pre-harvest seasons in stunting ...

    African Journals Online (AJOL)

    Minimum meal frequency, minimum acceptable diet and poor dietary diversity increased considerably in pre-harvest compared to post-harvest season in the lowland zone. Feeding practices and maternal age were predictors of wasting, while women's dietary diversity and children age was predictor of child dietary diversity ...

  7. Effect of seasonal drawdown variations on groundwater quality in ...

    African Journals Online (AJOL)

    user

    2013-07-24

    Jul 24, 2013 ... each of the 10 selected zones and special attention was given to two abattoirs in .... levels during the two seasons was also shown in Figure. 1. There were ..... Ground Water and Surface Water Pollution by. Open Refuse dump ...

  8. Seasonal Variation of Atmospheric Composition of Water-Soluble ...

    African Journals Online (AJOL)

    `123456789jkl''''#

    and 2006 wet season campaigns using a “Gent” PM10 stacked filter unit sampler with sequential Nuclepore polycarbonate filters. ... the effectiveness of abatement strategies for relevant ..... Giri, D., V.K. Murthy, P.R. Adhikary, and. S.N. Khanal ...

  9. Seasonal Variations in the Composition and Distribution of ...

    African Journals Online (AJOL)

    The composition and distribution of planktonic fauna (adult form of zooplankton and planktonic juvenile forms of higher animals) within the eastern part of the Lagos Lagoon were investigated in July, 2008 and March, 2009 representing rainy and dry season respectively. Samples of water and planktonic fauna were ...

  10. Seasonal behavior of carbonyls and source characterization of formaldehyde (HCHO) in ambient air

    Science.gov (United States)

    Lui, K. H.; Ho, Steven Sai Hang; Louie, Peter K. K.; Chan, C. S.; Lee, S. C.; Hu, Di; Chan, P. W.; Lee, Jeffrey Chi Wai; Ho, K. F.

    2017-03-01

    Gas-phase formaldehyde (HCHO) is an intermediate and a sensitive indicator for volatile organic compounds (VOCs) oxidation, which drives tropospheric ozone production. Effective photochemical pollution control strategies demand a thorough understanding of photochemical oxidation precursors, making differentiation between sources of primary and secondary generated HCHO inevitable. Spatial and seasonal variations of airborne carbonyls based on two years of measurements (2012-2013), coupled with a correlation-based HCHO source apportionment analysis, were determined for three sampling locations in Hong Kong (denoted HT, TC, and YL). Formaldehyde and acetaldehyde were the two most abundant compounds of the total quantified carbonyls. Pearson's correlation analysis (r > 0.7) implies that formaldehyde and acetaldehyde possibly share similar sources. The total carbonyl concentration trends (HT rural). A regression analysis further quantifies the relative primary HCHO source contributions at HT (∼13%), TC (∼21%), and YL (∼40%), showing more direct vehicular emissions in urban than rural areas. Relative secondary source contributions at YL (∼36%) and TC (∼31%) resemble each other, implying similar urban source contributions. Relative background source contributions at TC could be due to a closed structure microenvironment that favors the trapping of HCHO. Comparable seasonal differences are observed at all stations. The results of this study will aid in the development of a new regional ozone (O3) control policy, as ambient HCHO can enhance O3 production and also be produced from atmospheric VOCs oxidation (secondary HCHO).

  11. Seasonal variations in biochemical composition of some seaweeds from Goa coast

    Digital Repository Service at National Institute of Oceanography (India)

    Sumitra-Vijayaraghavan; Rajagopal, M.D.; Wafar, M.V.M.

    high in H. musciformis, whereas P. tetrastromatica, C. media and U. fasciata were rich in protein. The biochemical constituents in general did not show marked seasonal variations and it was attributed to the reproductive pattern of the algae studied...

  12. Variation of respiratory syncytial virus and the relation with meteorological factors in different winter seasons.

    NARCIS (Netherlands)

    Meerhoff, T.J.; Paget, W.J.; Kimpen, J.L.; Schellevis, F.

    2009-01-01

    Background: Respiratory syncytial virus (RSV) is the most important viral agent causing severe respiratory disease in infants and children. In temperate climates, RSV activity typically peaks during winter. We have described the seasonal variation in RSV activity and investigated which

  13. Seasonal variations in the fouling diatom community structure from a monsoon influenced tropical estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Mitbavkar, S.; Anil, A.C.

    Seasonal variations in the fouling diatom community from a monsoon influenced tropical estuary were investigated. The community composition did not differ significantly between stainless steel and polystyrene substrata due to dominance by Navicula...

  14. Seasonal variation of wind direction fluctuations vs Pasquill stabilities in complex terrain

    Digital Repository Service at National Institute of Oceanography (India)

    Sadhuram, Y.; Murthy, K.P.R.V.

    The authors have studied the seasonal variation of sigma theta (the standard deviation of wind direction fluctuations) vs Pasquill stabilities over complex terrain. It is found that the values of sigma theta are quite high in the month of April...

  15. Seasonal variations in the diet and food selection of the Algerian ...

    African Journals Online (AJOL)

    Seasonal variations in the diet and food selection of the Algerian hedgehog ... in prey selection, and a notable shift in food preference was observed during autumn. ... of this species before hibernation, in terms of quantity and/or quality.

  16. Seasonal and biological variation of urinary epinephrine, norepinephrine, and cortisol in healthy women

    DEFF Research Database (Denmark)

    Hansen, Åse Marie; Garde, A H; Skovgaard, L T

    2001-01-01

    There is a significant circadian and seasonal periodicity in various endocrine functions. The present study describes the within-day and seasonal fluctuation for urinary catecholamines and cortisol and estimates the within- (CV(i)) and between-subject (CV(g)) coefficients of variation for healthy...

  17. Seasonal and socio-economic variations in clinical and self-reported ...

    African Journals Online (AJOL)

    Seasonal and socio-economic variations in clinical and self-reported malaria in Accra, Ghana: Evidence from facility data and a community survey. ... Conclusions: Understanding these seasonal and geographic patterns have implications for both prevention and treatment of malaria-like morbidity in both children and adults ...

  18. Effects of seasonal variation of photosynthetic capacity on the carbon fluxes of a temperate deciduous forest

    Science.gov (United States)

    David Medvigy; Su-Jong Jeong; Kenneth L. Clark; Nicholas S. Skowronski; Karina V. R. Schäfer

    2013-01-01

    Seasonal variation in photosynthetic capacity is an important part of the overall seasonal variability of temperate deciduous forests. However, it has only recently been introduced in a few terrestrial biosphere models, and many models still do not include it. The biases that result from this omission are not well understood. In this study, we use the Ecosystem...

  19. Physiological implications of seasonal variation in membrane-associated calcium in red spruce mesophyll cells

    Science.gov (United States)

    D.H. DeHayes; P.G. Schaberg; G.J. Hawley; C.H. Borer; J.R. Cumming; J.R. Strimbeck

    1997-01-01

    We examined the pattern of seasonal variation in total foliar calcium (Ca) pools and plasma membrane-associated Ca (mCa) in mesophyll cells of current-year and 1-year-old needles of red spruce (Picea rubens Sarg.) and the relationship between mCa and total foliar Ca on an individual plant and seasonal basis. Foliar samples were collected from...

  20. Seasonal genetic variation associated with population dynamics of a poecilogonous polychaete worm

    DEFF Research Database (Denmark)

    Thonig, Anne; Banta, Gary Thomas; Hansen, Benni Winding

    2017-01-01

    Poecilogonous species show variation in developmental mode, with larvae that differ both morphologically and ecologically. The spionid polychaete Pygospio elegans shows variation in developmental mode not only between populations, but also seasonally within populations. We investigated...... differentiation at two of the sites. The seasonal genetic shift correlated with the appearance of new size cohorts in the populations. Additionally, we found that the genetic composition of reproductive individuals did not always reflect the genetic composition of the entire sample, indicating that variance...

  1. Seasonal Variation of the Material Transport Processes in the Ariake Sea

    OpenAIRE

    Manda, Atsuyoshi; Kanehara, Hisao; Aoshima, Takashi; Kinoshita, Tsukasa; Uchida, Jun; Nakata, Hideaki; Yanagi, Tetsuo

    2010-01-01

    Seasonal variation of the salt fluxes in the middle part of the Ariake Sea have been investigated by modeling with hydrographic and meteorological data. The salt flux due to the seasonally averaged density-driven currents accounts for approximately 60% of the total salt flux during summer. The salt flux due to the other processes, that are not treated explicitly, such as the tidal pumping, tideinduced residual currents, and short-term variations of the density- and winddriven currents dominat...

  2. Seasonal variations in the fatty acid composition of Greek wild rabbit meat.

    Science.gov (United States)

    Papadomichelakis, G; Zoidis, E; Pappas, A C; Hadjigeorgiou, I

    2017-12-01

    The fatty acid (FA) profile of the Longissimus thoracis et lumborum muscle (LL) was used to investigate seasonal variation (September, November and March) in wild rabbits from Lemnos Island (Greece). The n-3 FA were particularly high during early March in comparison (P<0.05) with late September and late November. Thrombogenicity index (TI) values were lower in March (P<0.05) compared to the other periods. High concentrations of odd- and branched-chain FA were found in the meat of wild rabbits; however, they were not different among the considered periods of the year. The present results showed that wild rabbit meat has a desirable FA profile, particularly during early spring, and it could be a good source of bioactive FA in human nutrition. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Seasonal variations of physico-chemical properties of the Great ...

    African Journals Online (AJOL)

    use

    characteristics and nutrient dynamics in the network of. *Corresponding author. ... salt units that produce edible salt and industrial salt operate in this ... Monthly variations of water temperature in different stations during the study period. area.

  4. Seasonal and locational variations in children's play: implications for wellbeing.

    Science.gov (United States)

    Ergler, Christina R; Kearns, Robin A; Witten, Karen

    2013-08-01

    Physical activity, through independent outdoor play, has come to the fore as a way to improve children's health through it fostering healthy mental and social as well as physiological development. However, in many high-income countries children's autonomous play opportunities have diminished due to urban intensification and declining parental license. Regardless of this trend, children's play varies across countries, cities, cultures and seasons. This paper offers new insights into the complexities of play as a vital aspect of children's wellbeing. Within the context of New Zealand - whose citizens generally regard themselves as outdoor people - this paper explores why 'play' might resonate differently across localities and seasons. We contrast the play affordances provided by Auckland's central city (dominated by apartment living) with Beach Haven, a suburban area. We employed a multi-method approach and included 20 children and their parents who were recruited through school and summer holiday programs embracing different gender and ethnicities to reflect the general cultural mix of the respective neighbourhoods. We advance two arguments. First, we suggest that the rarity of children playing outdoors unsupervised normalises supervised indoor play and reduces children's opportunities to see outdoor play as an alternative to interior or supervised pastimes. Second, we follow Bourdieu's theory of practice to argue that the regard parents and children have towards outdoor play reflects locally constituted beliefs about what is seasonally 'appropriate' children's activity. We found that extra-curricular activities and supervised excursions are undertaken in the central city all year around and only vary between social groups by the type of destination. In the suburb, independent outdoor play in summer represents children's main business after school in ways that enhance their environmental literacy and potential future health gain. For others these symbolic values

  5. Seasonal variation in concentration of radon and thoron at non-uranium mines in China

    International Nuclear Information System (INIS)

    Cui Hongxing; Wu Yunyun; Zhang Qingzhao; Shang Bing

    2009-01-01

    Objective: To study the seasonal variation in concentrations of radon and thoron in non-uranium mine. Methods: Eight kinds of mineral types from 9 non-uranium mines were selected, including copper, gold, aluminium, manganese, antimonium, tungsten, copper-nickel and coal mines in 6 provinces, such as Yunnan, Shandong, Xinjiang, Heilongjiang, Hunan and Guizhou. LD-P R-T discriminative detectors were used to measure radon and thoron concentrations in underground mines during four seasons in one year. Results: Radon concentrations in underground mines showed a significantly seasonal variation. Radon concentration ranged from 35.5 to 4841 Bq/m 3 in summer, and the average value in four mines exceeded 1000 Bq/m 3 of the control limit for workplace (GB 18871-2002) . In winter, radon concentration ranged from 5 to 1917 Bq/m 3 , only one of them exceeded the control limit. The ratio of radon from summer to winter ranged from 2 to 12. Ventilation was one of the main factors which influenced the seasonal variation of radon. While the thoron concentration in underground mines showed a tendency that it was higher in summer and lower in winter. It was difficult to attain representative values for thoron, due to the influence of location of detectors. The seasonal variation of thoron should be further studied. Conclusions: Seasonal variation for radon and thoron should be taken into account to estimate the effective dose to miners. The values of radon concentration during the short term should be corrected. (authors)

  6. Seasonal and Temporal Variation of Volatile Organic Compounds ...

    African Journals Online (AJOL)

    ... with the ambient concentrations of VOCs. The principal component analysis revealed that the major sources of VOCs in Isolo are mainly Anthropogenic and four (4) factors were identified as sources of VOCs in the studied area with Industrial and emissions from traffic dominating. Key words: Significant, Pollution, Spatial, ...

  7. Seasonal variation in Chironomid emergence from coastal pools

    Directory of Open Access Journals (Sweden)

    Alexander T. Egan

    2015-07-01

    Full Text Available Understanding the phenology of emergences can be useful in determining seasonal chironomid life cycle patterns, which are often influenced by ice cover and temperature in cold climates. Lake Superior is the largest lake in North America and with a mean surface temperature of 3.9 °C influences regional climate. Coastal pools at Isle Royale, a wilderness archipelago in the northern part of the lake, occur in dense patches on low-gradient volcanic bedrock between the lakeshore and forest, creating variable microhabitats for Chironomidae. Four sites were sampled monthly from April to October, 2010. Surface-floating pupal exuviae were collected from a series of pools in two zones: a lower zone near the lake influenced by wave splash, and an upper zone near the forest and influenced by upland runoff. We used Jaccard’s and Whittaker’s diversity indexes to test community similarity across months. Temperature loggers in pools collected hourly readings for most of the study. Assemblage emergences were stable in upper pools, with significant similarity across late spring and summer months. Assemblages were seasonally variable in lower pools, with significant dissimilarity across spring, summer, and fall months. Few species in either zone were unique to spring or fall months. However, many summer species in the splash zone had a narrow emergence period occurring during calm weather following distinct increases in mean water temperature. Regardless of input of cold lake water to the lower zone, pools from both zones generally had corresponding temperature trends.

  8. Seasonal variation in radiocesium concentrations in three tree species

    International Nuclear Information System (INIS)

    Garten, C.R. Jr.; Briese, L.A.; Sharitz, R.R.; Gentry, J.B.

    1975-01-01

    Radiocesium concentrations in leaves and stems of black willow (Salix nigra), wax myrtle (Myrica cerifera), and tag alder (Alnus serrulata) trees inhabiting a floodplain contaminated by production-reactor effluents were measured over 1 year. In willow and myrtle trees, leaf radiocesium levels were highest in the spring and declined during the growing season; stem levels remained relatively unchanged or exhibited a slight increase. Seasonal changes in alder tree parts depended on the site examined. The relationship among component parts was essentially consistent across species and collecting sites in the summer. The radiocesium concentrations in order of rank were: roots greater than or equal to leaves greater than stems. Species differences in component-part radiocesium levels were dependent on the part sampled and the collecting site examined. Mean soil to plant-part concentration factors in summer ranged from 0.9 to 7.6, and species means across leaves, stems, and roots averaged 2.1, 3.8, and 6.2 for alder, willow, and myrtle trees, respectively

  9. Seasonal and daily variation of directions of approach to ground and balloon stations

    International Nuclear Information System (INIS)

    Orozco, A.; Gall, R.

    1975-01-01

    The seasonal and daily variations of approach directions induced by the distortion of magnetic cavity has been studied by trajectory tracing technique in magnetospheric models. The main characteristics of these variations are reported here for McMurdo, Thule and Fort Churchill. (orig./WBU) [de

  10. Spatial and seasonal variations of the contamination within water body of the Grand Canal, China

    NARCIS (Netherlands)

    Wang, X.L.; Han, Jingyi; Xu, L.G.; Zhang, Q.

    2010-01-01

    To delineate the character of contaminations in the Grand Canal, China, a three-year study (2004-2006) was conducted to investigate variations the water quality in the canal. Results showed that the variation of water quality within the Grand Canal was of there is remarkable spatial and seasonal

  11. Occurrence, seasonal variation and risk assessment of antibiotics in the reservoirs in North China.

    Science.gov (United States)

    Li, Nan; Zhang, Xinbo; Wu, Wei; Zhao, Xinhua

    2014-09-01

    The occurrence and seasonal variability of five groups (tetracycline, quinolone, chloramphenicol, macrolide and sulfonamide) of antibiotics were investigated in the surface water of four reservoirs. The dissolved concentrations of 29 antibiotics were in the ngL(-1) level. Trace levels of all target antibiotics were analyzed using solid-phase extraction followed by liquid chromatography electrospray tandem mass spectrometry. All of the antibiotics were detected at all sampling sites, indicating widespread occurrence of antibiotics in the study area. The detection of florfenicol, josamycin, kitasamycin, spiramycin and sulfameter is the first report of these compounds in reservoir samples. The results showed an association between the presence of some antibiotics at Panjiakou reservoir and cage culture of fish. Twenty-three types of antibiotics showed significant seasonal variations (prisk assessment showed that all antibiotics detected could cause very low risk to algae, daphnid and fish. Further health risk need to be investigated because these reservoirs are drinking water sources. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Identification of a potential toxic hot spot associated with AVS spatial and seasonal variation.

    Science.gov (United States)

    Campana, O; Rodríguez, A; Blasco, J

    2009-04-01

    In risk assessment of aquatic sediments, much attention is paid to the difference between acid-volatile sulfide (AVS) and simultaneously extracted metals (SEMs) as indicators of metal availability. Ten representative sampling sites were selected along the estuary of the Guadalete River. Surficial sediments were sampled in winter and summer to better understand SEM and AVS spatial and seasonal distributions and to establish priority risk areas. Total SEM concentration (SigmaSEM) ranged from 0.3 to 4.7 micromol g(-1). It was not significantly different between seasons, however, it showed a significant difference between sampling stations. AVS concentrations were much more variable, showing significant spatial and temporal variations. The values ranged from 0.8 to 22.4 micromol g(-1). The SEM/AVS ratio was found to be <1 at all except one station located near the mouth of the estuary. The results provided information on a potential pollution source near the mouth of the estuary, probably associated with vessel-related activities carried out in a local harbor area located near the station.

  13. Seasonal variation in the essential oil of Pilocarpus microphyllus Stapf.

    Directory of Open Access Journals (Sweden)

    FRANCISCA S. N. TAVEIRA

    2003-03-01

    Full Text Available The essential oils of the leaves and fine stems of Pilocarpus microphyllus, collected on iron mineralized soil of the Serra de Carajás, Southeast of Pará State, Brazil, during the rainy and dry seasons, were obtained by hydrodistillation and analyzed by GC-MS. The main identified compounds were 2-tridecanone, beta-caryophyllene, 2-pentadecanone, caryophyllene oxide and germacrene D. Their percentage contents varied with the season, the greater values having been detected mainly in the rainy season. For 2-tridecanone and beta-caryophyllene the higher values were observed in the fine stem oils for the former, and in the leaf oils for the latter. For 2-pentadecanone, caryophyllene oxide and germacrene D they were also in the leaf oils. In general, the leaf oils were very distinguishable from those of fine stem oils, even in the same specimen.Os óleos essenciais das folhas e galhos finos de Pilocarpus microphyllus, coletado em solo mineralizado com ferro, na Serra de Carajás, Sudeste do Pará, Brasil, durante as estações chuvosa e seca, foram obtidos por hidrodestilação e analisados por GC-MS. Os principais compostos identificados foram 2-tridecanona, beta-cariofileno, 2-pentadecanona, óxido de cariofileno e germacreno D. Seus teores percentuais variam com a estação, embora os maiores valores tenham sido detectados principalmente na estação chuvosa. Para 2-tridecanona e beta-cariofileno os valores mais expressivos foram observados nos óleos de galhos finos, para o primeiro, e nos óleos das folhas, para o útimo. Para 2-pentadecanona, óxido de cariofileno e germacreno D, os valores mais altos foram, também, nos óleos das folhas. Em geral, os óleos das folhas se apresentaram muito distintos em relação aos galhos finos, assim como também no mesmo espécime.

  14. Seasonal variation in the biochemical composition of red seaweed ...

    Indian Academy of Sciences (India)

    ence of the nutritional quality of water that can be used for mass cultivation of Catenella ... purposes such as feed, fertilizer and as a source ... organic matter in the ecosystem (Mitchell and ..... colourant in marine fish aquaculture (Johnson.

  15. Lithological and seasonal variations in radon concentrations in Cypriot groundwaters

    International Nuclear Information System (INIS)

    Tasoula Kiliari; Anastasia Tsiaili; Ioannis Pashalidis

    2010-01-01

    The paper presents and discusses radon activity concentrations in Cypriot groundwater systems as a function of the background lithology and seasonal/meteorological conditions using an airborne radon monitoring system (ARM) after separation of radon by out-gassing. Radiometric analysis of groundwater samples obtained from non-contaminated systems showed that radon concentration in groundwaters varies strongly (0.1-10 Bq L -1 ) depending mainly on the hosting geological matrix but also to lesser degree on atmospheric/meteorological conditions. The associated excess annual dose has been estimated to range between 10 -6 and 10 -4 mSv y -1 , which is an insignificant contribution to the radiation exposure of the Cypriot population caused by airborne radon (0.5 ± 0.4 mSv y -1 ). (author)

  16. Seasonal variations of arsenic in mussels Mytilus galloprovincialis

    Science.gov (United States)

    Klarić, Sanja; Pavičić-Hamer, Dijana; Lucu, Čedomil

    2004-10-01

    Total arsenic concentration in the edible part of mussels Mytilus galloprovincialis was evaluated seasonally in the coastal area of Rijeka Bay (North Adriatic Sea, Croatia). Sampling stations were located close to the City of Bakar with no industrial facilities (site 1), in the vicinity of the oil refinery and oil thermoelectric power plant (Urinj, site 2), and 4 miles away from the Plomin coal thermoelectric power plant (Brseč village, site 3). Additionally, the concentration of arsenic in the tail muscle of the lobster Nephrops norvegicus, collected in Rijeka Bay, was studied. During winter at sites 2 and 3, the total arsenic in the edible part of the mussels was 16.4 mg As/kg FW (FW=fresh weight) and 4.38 mg As/kg FW, respectively, and increased during springtime at site 2 (6.5 mg As/kg FW) compared to the rest of the year, when individual total arsenic concentration at all sites ranged from 1.7 to 3.7 mg As/kg FW. In the winter (sites 2 and 3) and springtime (site 2) there was no correlation between the length of the mussel shell and the arsenic concentration in the edible part of the mussels. In the other seasons, at sites 1, 2 and 3, there was a correlation between arsenic in the edible part of mussels and shell length in most cases (correlation coefficients r varied from 0.64 to 0.85; P edible part of the mussels shows linearity with a high regression coefficient (r =0.914; P edible part during winter. In addition, a linear relationship was found between body length and arsenic concentration in the tail muscle (mean 17.11±4.48 mg As/kg FW) of the Norway lobster.

  17. Tidal and seasonal variation in particulate and dissolved organic carbon in the western dutch Wadden Sea and Marsdiep tidal inlet

    Science.gov (United States)

    Cadée, G. C.

    Seasonal variation in POC and DOC was measured in the Marsdiep tidal inlet of the Wadden Sea from March 1978 to June 1981, and compared with tidal variation. A POC peak was coincident with the phytoplankton peak (except for 1981), whereas a DOC peak occurred about one month later indicating autolysis and degradation of phytoplankton rather than excretion as the main source of this DOC. DOC production calculated from the spring increase amounted to 4.2 mg C·1 -1 or about 40% of the annual phytoplankton primary production in the area. This means that a large part of the phytoplankton production is not used directly by primary consumers but is converted into DOC. Tidal variation in DOC was correlated with salinity, pointing to a fresh water source for the bulk of it. POC was correlated with suspended matter content and phaeopigment, and slightly less with chlorophyll. Compared with the seasonal variation, tidal variation in chlorophyll and temperature was relatively small, but large in POC, DOC, suspended matter and salinity. Although import of POC and export of DOC through the Marsdiep inlet is large on an annual base, the transport cannot be measured directly because of the variability and precision limits of the measurements and as differences in content between ebb and flood current are only 15 and 5% of the POC and DOC content, respectively.

  18. A further contribution to the seasonal variation of weighted mean temperature

    Science.gov (United States)

    Ding, Maohua; Hu, Wusheng

    2017-12-01

    The weighted mean temperature Tm is a variable parameter in the Global Navigation Satellite System (GNSS) meteorology and the Askne-Nordius zenith wet delay (ZWD) model. Some parameters about the Tm seasonal variation (e.g. the annual mean value, the annual range, the annual and semi-annual amplitudes, and the long-term trend) were discussed before. In this study, some additional results about the Tm seasonal variation on a global scale were found by using the Tm time series at 309 global radiosonde sites. Periodic signals of the annual and semi-annual variations were detected in these Tm time series by using the Lomb-Scargle periodogram. The annual variation is the main component of the periodic Tm in non-tropical regions, while the annual variation or the semiannual variation can be the main component of the periodic Tm in tropics. The mean annual Tm almost keeps constant with the increasing latitude in tropics, while it decreases with the increasing latitude in non-tropical regions. From a global perspective, Tm has an increasing trend of 0.22 K/decade on average, which may be caused by the global warming effects. The annual phase is almost found in about January for the non-tropical regions of the Southern Hemisphere and in about July for the non-tropical regions of the Northern Hemisphere, but it has no clear symmetry in tropics. Unlike the annual phase, the geographical distributions of semi-annual phase do not follow obvious rules. In non-tropical regions, the maximum and minimum Tm of the seasonal model are usually found in respective summer and winter days while the maximum and minimum Tm are distributed over a whole year but not in any fixed seasons for tropical regions. The seasonal model errors increase with the increasing value of annual amplitude. A primary reason for the irregular seasonal variation in tropics is that Tm has rather small variations in this region.

  19. Occurrence, distribution and seasonal variation of organophosphate flame retardants and plasticizers in urban surface water in Beijing, China

    International Nuclear Information System (INIS)

    Shi, Yali; Gao, Lihong; Li, Wenhui; Wang, Yuan; Liu, Jiemin; Cai, Yaqi

    2016-01-01

    The occurrence, spatial distribution and seasonal variation of 14 organophosphate esters (OPEs) were investigated in urban surface water (river and lake water) from July 2013 to June 2014 in Beijing, China. Sewage influent and effluent samples, as well as rainwater and road runoff samples were also analyzed as the potential sources of OPEs in surface water. Tris(2-chloro-1-methylethyl) phosphate (TCPP) and tris(2-chloroethyl) phosphate (TCEP) were the most abundant OPEs with the average concentrations of 291 ng L"−"1 and 219 ng L"−"1, respectively. Relatively high concentrations of OPEs were detected in rivers located at southern and eastern urban of Beijing, which was probably attributed to the treated and untreated sewage discharge. Besides, higher levels of OPEs were observed in urban surface water in the summer, and the wet deposition (rainfall) was confirmed to be an important factor for this observation. Risk assessment showed low or medium risk of OPEs for the organisms (algae, crustacean and fish). - Highlights: • High levels of OPEs were detected in urban surface water of Beijing, China. • Seasonal variation revealed higher levels of OPEs in the summer. • Wastewater, rainwater and road runoff samples were analyzed as sources of OPEs. • The risks of OPEs to the organisms (algae, crustacean and fish) were assessed. - The occurrence, spatial distribution and seasonal variation of OPEs in urban surface water were investigated from densely populated big city (Beijing, China).

  20. Seasonal variation of the protozooplanktonic community in a tropical oligotrophic environment (Ilha Solteira reservoir, Brazil).

    Science.gov (United States)

    Mansano, A S; Hisatugo, K F; Leite, M A; Luzia, A P; Regali-Seleghim, M H

    2013-05-01

    The seasonal variation of the protozooplanktonic community (ciliates and testate amoebae) was studied in a tropical oligotrophic reservoir in Brazil, which was under the influence of two contrasting climatic seasons (rainy/warm and dry/cold). The aim of this study was to evaluate the effect of these climatic changes on physical, chemical and biological variables in the dynamic of this community. The highest mean density of total protozoans occurred in the rainy/warm season (5683.2 ind L-1), while the lowest was in the dry/cold (2016.0 ind L-1). Considering the seasonal variations, the protozoan groups that are truly planktonic, such as the oligotrichs (Spirotrichea), predominated in the dry season, whereas during the rainy season, due to the material input and resuspension of sediment, sessile protozoans of the Peritrichia group were the most important ones. The dominant protozoans were Urotricha globosa, Cothurnia annulata, Pseudodifflugia sp. and Halteria grandinella. The highest densities of H. grandinella were associated with more oxygenated and transparent water conditions, while the highest densities of C. annulata occurred in sites with high turbidity, pH and trophic state index (TSI). The study demonstrated that density and composition of protozooplanktonic species and groups of the reservoir suffered seasonal variation due to the environmental variables (mainly temperature, turbidity, water transparency, dissolved oxygen and TSI) and the biological variables (e.g. morphological characteristics, eating habits and escape strategies from predation of the species).

  1. Seasonal variations in physicochemical profiles of Guduchi Satva (starchy substance from Tinospora cordifolia [Willd.] Miers

    Directory of Open Access Journals (Sweden)

    Rohit Sharma

    2013-01-01

    Full Text Available Guduchi Satva (GS, the starchy material extracted from the Guduchi stem is well-known Ayurvedic single drug formulation having a wide range of therapeutic utility. Species of the plant, stem size, collection time, season and maturity of the plant may affect the yield and physico-chemical profile of GS. However, published data on such variations is lacking. Considering this, present study is planned to screen seasonal variations in physico-chemical profile of GS. 18 batches of GS were prepared in six different seasons (3 batches in each season and findings were systematically recorded. The obtained Satva was further subjected to relevant physico-chemical parameters. Principal component analysis method was adopted to analyze variations. Maximum yield of Satva was obtained in Shishira Ritu(January-February while the minimum in Grishma (May-June. Variation in taste and color was found in Satva prepared in Varsha Ritu. All functional groups were found to be same in each season. Total alkaloidal contents found bit higher in Varsha and Vasanta. More residual x-variance in alcohol soluble extract and more leverage were observed in water soluble extract due to impact of seasonal spells.

  2. Atmospheric deposition of mercury in central Poland: Sources and seasonal trends

    Science.gov (United States)

    Siudek, Patrycja; Kurzyca, Iwona; Siepak, Jerzy

    2016-03-01

    Atmospheric deposition of total mercury was studied at two sites in central Poland, between April 2013 and October 2014. Hg in rainwater (bulk deposition) was analyzed in relation to meteorological parameters and major ions (H+, NO3-, Cl-, SO42 -) in order to investigate seasonal variation, identify sources and determine factors affecting atmospheric Hg chemistry and deposition. Total mercury concentrations varied between 1.24 and 22.1 ng L- 1 at the urban sampling site (Poznań) and between 0.57 and 18.3 ng L- 1 in the woodland protected area (Jeziory), with quite similar mean values of 6.96 and 6.37 ng L- 1, respectively. Mercury in precipitation exhibited lower spatial variability within the study domain (urban/forest transect) than the concentrations determined during other similar observations, reflecting the predominant influence of the same local sources. In our study, a significant seasonal pattern of Hg deposition was observed at both sampling sites, with higher and more variable concentrations of Hg reported for the urban area. In particular, deposition values of Hg were higher in the samples attributed to relatively large precipitation amounts in the summer and in those collected during the winter season (the result of higher contributions from combustion sources, i.e. intensive combustion of fossil fuels in residential and commercial boilers, individual power/heat-generating plants). In addition, a significant relationship between Hg concentration and precipitation amount was found while considering different types of wintertime samples (i.e. rain, snow and mixed precipitation). The analysis of backward trajectories showed that air masses arriving from polluted regions of western Europe and southern Poland largely affected the amount of Hg in rainwater. A seasonal variation in Hg deposition fluxes was also observed, with the maximum value of Hg in spring and minimum in winter. Our results indicated that rainwater Hg and, consequently, the wet deposition

  3. Seasonal and diurnal variations of atmospheric mercury across the US determined from AMNet monitoring data

    Directory of Open Access Journals (Sweden)

    X. Lan

    2012-11-01

    Full Text Available Speciated atmospheric mercury observations collected over the period from 2008 to 2010 at the Environmental Protection Agency and National Atmospheric Deposition Program Atmospheric Mercury Network sites (AMNet were analyzed for its spatial, seasonal, and diurnal characteristics across the US. Median values of gaseous elemental mercury (GEM, gaseous oxidized mercury (GOM and particulate bound mercury (PBM at 11 different AMNet sites ranged from 148–226 ppqv (1.32–2.02 ng m−3, 0.05–1.4 ppqv (0.47–12.4 pg m−3 and 0.18–1.5 ppqv (1.61–13.7 pg m−3, respectively. Common characteristics of these sites were the similar median levels of GEM as well as its seasonality, with the highest mixing ratios occurring in winter and spring and the lowest in fall. However, discernible differences in monthly average GEM were as large as 30 ppqv, which may be caused by sporadic influence from local emission sources. The largest diurnal variation amplitude of GEM occurred in the summer. Seven rural sites displayed similar GEM summer diurnal patterns, in that the lowest levels appeared in the early morning, and then the GEM mixing ratio increased after sunrise and reached its maxima at noon or in the early afternoon. Unlike GEM, GOM exhibited higher mixing ratios in spring and summer. The largest diurnal variation amplitude of GOM occurred in spring for most AMNet sites. The GOM diurnal minima appeared before sunrise and maxima appeared in the afternoon. The increased GOM mixing ratio in the afternoon indicated a photochemically driven oxidation of GEM resulting in GOM formation. PBM exhibited diurnal fluctuations in summertime. The summertime PBM diurnal pattern displayed daily maxima in the early afternoon and lower mixing ratios at night, implying photochemical production of PBM in summer.

  4. Seasonal variations in the concentration and solubility of elements in atmospheric particulate matter: a case study in Northern Italy

    Directory of Open Access Journals (Sweden)

    Canepari S.

    2013-04-01

    Full Text Available Atmospheric particulate matter is characterized by a variety of chemical components, generally produced by different sources. Chemical fractionation of elements, namely the determination of their extractable and residual fractions, may reliably increase the selectivity of some elements as tracers of specific PM sources. Seasonal variations of atmospheric particulate matter concentration in PM10 and PM2.5, of elemental concentration in PM10 and PM2.5, of the extractable and residual fraction of elements in different size fractions in the range 0.18 – 18 μm are reported in this paper. The effect of the ageing of the air masses is discussed.

  5. Seasonal variations of water vapor in the tropical lower statosphere

    Science.gov (United States)

    Mote, Philip W.; Rosenlof, Karen H.; Holton, James R.; Harwood, Robert S.; Waters, Joe W.

    1995-01-01

    Measurments of stratospheric water vapor by the Microwave Limb Sounder (MLS) aboard the Upper Atmosphere Research Satellite (UARS) show that in the tropical lower statosphere, low-frequency variations are closely related to the annual cycle in tropical tropopause temperatures. Tropical stratospheric air appears to retain information about the tropopause conditions it enconters for over a year as it rises through the stratosphere. A two-dimensional Lagrangian model is used to relate MLS measurements to the temperature that tropical air parcels encounter when crossing the 100 hPa surface.

  6. Seasonal Gravity Field Variations from GRACE and Hydrological Models

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Hinderer, Jacques; Lemoine, Frank G.

    2004-01-01

    . Four global hydrological models covering the same period in 2002–2003 as the GRACE observations were investigated to for their mutual consistency in estimates of annual variation in terrestrial water storage and related temporal changes in gravity field. The hydrological models differ by a maximum of 2...... µGal or nearly 5 cm equivalent water storage in selected regions. Integrated over all land masses the standard deviation among the annual signal from the four hydrological models are 0.6 µGal equivalent to around 1.4 cm in equivalent water layer thickness. The estimated accuracy of the annual...

  7. Seasonal variation of mercury vapor concentrations in industrial ...

    African Journals Online (AJOL)

    Mercury has been known as a toxic substance that could raise potential risks to human health. The main anthropogenic sources of mercury pollution in air include combustion of fossil fuel, metal smelting and processing, and vehicle transportation all of which exist in Ahvaz city in Southwestern Iran. Ambient air mercury ...

  8. Seasonal variation of photosynthetic model parameters and leaf area index from global Fluxnet eddy covariance data

    Science.gov (United States)

    Groenendijk, M.; Dolman, A. J.; Ammann, C.; Arneth, A.; Cescatti, A.; Dragoni, D.; Gash, J. H. C.; Gianelle, D.; Gioli, B.; Kiely, G.; Knohl, A.; Law, B. E.; Lund, M.; Marcolla, B.; van der Molen, M. K.; Montagnani, L.; Moors, E.; Richardson, A. D.; Roupsard, O.; Verbeeck, H.; Wohlfahrt, G.

    2011-12-01

    Global vegetation models require the photosynthetic parameters, maximum carboxylation capacity (Vcm), and quantum yield (α) to parameterize their plant functional types (PFTs). The purpose of this work is to determine how much the scaling of the parameters from leaf to ecosystem level through a seasonally varying leaf area index (LAI) explains the parameter variation within and between PFTs. Using Fluxnet data, we simulate a seasonally variable LAIF for a large range of sites, comparable to the LAIM derived from MODIS. There are discrepancies when LAIF reach zero levels and LAIM still provides a small positive value. We find that temperature is the most common constraint for LAIF in 55% of the simulations, while global radiation and vapor pressure deficit are the key constraints for 18% and 27% of the simulations, respectively, while large differences in this forcing still exist when looking at specific PFTs. Despite these differences, the annual photosynthesis simulations are comparable when using LAIF or LAIM (r2 = 0.89). We investigated further the seasonal variation of ecosystem-scale parameters derived with LAIF. Vcm has the largest seasonal variation. This holds for all vegetation types and climates. The parameter α is less variable. By including ecosystem-scale parameter seasonality we can explain a considerable part of the ecosystem-scale parameter variation between PFTs. The remaining unexplained leaf-scale PFT variation still needs further work, including elucidating the precise role of leaf and soil level nitrogen.

  9. Carbonate system and nutrients in the Pearl River estuary, China: Seasonal and inter-annual variations

    Science.gov (United States)

    Guo, X.

    2017-12-01

    Located in southern China and surrounded by several metropolis, the Pearl River estuary is a large subtropical estuary under significant human perturbation. We examined the impact of sewage treatment rate on the water environmental factors. Carbonate system parameters (Dissolved inorganic carbon or DIC, Total alkalinity or TA, and pH), and nutrients were surveyed in the Pearl River estuary from 2000 to 2015. Spatially, concentrations of nutrients were high at low salinity and decreased with salinity in both wet and dry seasons although seasonal variation occurred. However, distribution patterns of DIC and TA differed in wet and dry seasons. In wet season, both DIC and TA were low at low salinity (600-1500 umol kg-1) and increased with salinity, but in dry season they were high at low salinity (3000-3500 umol kg-1) and decreased with salinity. Compared with the years before 2010, both values and distribution patterns of DIC, TA and pH were similar among the years in wet season, but they were conspicuously different in the upper estuary in dry season. Both DIC and TA were more than 1000 umol kg-1 lower than those in the years before 2010. For nutrients at low salinity, the ammonia concentration was much lower in the years after 2010 (200 vs. 400 umol kg-1 in wet season and 400 vs. 800 umol kg-1 in dry season), but nitrate concentration was slightly higher (180 vs 120 mmol kg-1 in wet season and 200 vs 180 mmol kg-1 in dry season). As a reference, carbonate system parameters and nutrients were stable among the 16 years in the adjacent northern South China Sea. The variations in biogeochemical processes induced by nutrients concentration and structure as a result of sewage discharge will be discussed in detail. The decrease in DIC, TA and nutrients in the upper Pearl River estuary after 2010 was due mainly to the improvement of sewage treatment rate and capacity.

  10. Black carbon at a coastal Antarctic station (Syowa Station: seasonal variation and transport processes

    Directory of Open Access Journals (Sweden)

    Keiichiro Hara

    2010-12-01

    Full Text Available Measurement of atmospheric black carbon (BC was carried out at Syowa Station Antarctica (69゜00′S, 39゜35′E from February 2004 until January 2007. The BC concentration at Syowa Station ranged from below detection to 176 ng m^. Higher BC concentrations were observed frequently from April until October. Increase of BC concentration may be associated with poleward flow due to the approach of a cyclone and or blocking event during winter-spring. The BC-rich air masses traveled through the lower troposphere from the Atlantic and Indian Oceans to Syowa (Antarctic coast. During the summer (November-February, the BC concentration showed a diurnal variation together with surface wind speed and increased in the presence of katabatic wind from the Antarctic continent. Considering the low BC source strength over the Antarctic continent, the higher BC concentration in the continental air (katabatic wind might be caused by long range transport of BC via the free troposphere from mid- and low- latitudes. The seasonal variation of BC at Syowa Station had a maximum in July-September, while at the other coastal stations (Halley, Neumayer, and Ferraz and a continental station (Amundsen-Scott, the maximum occurred in October. This difference may result from different transport pathways, significant contribution of source regions and scavenging of BC by precipitation during the transport from the source regions. During the austral summer, long-range transport of BC via the free troposphere is likely to make an important contribution to the ambient BC concentration along the Antarctic coasts.

  11. Seasonal Variations of Atmospheric CO2 over Fire Affected Regions Based on GOSAT Observations

    Science.gov (United States)

    Shi, Y.; Matsunaga, T.

    2016-12-01

    Abstract: The carbon dioxide (CO2) emissions released from biomass burning significantly affect the temporal variations of atmospheric CO2 concentrations. Based on a long-term (July 2009-June 2015) retrieved datasets by the Greenhouse Gases Observing Satellite (GOSAT), the seasonal cycle and interannual variations of column-averaged volume mixing ratios of atmospheric carbon dioxide (XCO2) in four fire affected continental regions were investigated. The results showed Northern Africa had the largest seasonal variations after removing its regional long-term trend of XCO2 with peak-to-peak amplitude of 6.2 ppm within the year, higher than central South America (2.4 ppm), Southern Africa (3.8 ppm) and Australia (1.7 ppm). The detrended regional XCO2 was found to be positively correlated with the fire CO2 emissions during fire activity period and negatively correlated with vegetation photosynthesis activity with different seasonal variabilities. Northern Africa recorded the largest change of seasonal variations of detrended XCO2 with a total of 12.8 ppm during fire seasons, higher than central South America, Southern Africa and Australia with 5.4 ppm, 6.7 ppm and 2.2 ppm, respectively. During fire episode, the positive detrended XCO2 was noticed during June-November in central South America, December-June in Northern Africa, May-November in Southern Africa. The Pearson correlation coefficients between the variations of detrended XCO2 and fire CO2 emissions from GFED4 (Global Fire Emissions Database v4) achieved best correlations in Southern Africa (R=0.77, p<0.05). Meanwhile, Southern Africa also experienced a significant negative relationship between the variations of detrended XCO2 and vegetation activity (R=-0.84, p<0.05). This study revealed that fire CO2 emissions and vegetation activity contributed greatly to the seasonal variations of GOSAT XCO2 dataset.

  12. ALMA observations of Titan's atmospheric chemistry and seasonal variation

    Science.gov (United States)

    Cordiner, Martin

    2017-04-01

    Titan is the largest moon of Saturn, with a thick (1.45 bar) atmosphere composed primarily of molecular nitrogen and methane. Photochemistry in Titan's upper atmosphere results in the production of a wide range of organic molecules, including hydrocarbons, nitriles and aromatics, some of which could be of pre-biotic relevance. Thus, we obtain insights into the possible molecular inventories of primitive (reducing) planetary atmospheres. Titan's atmosphere also provides a unique laboratory for testing our understanding of fundamental processes involving the chemistry and spectroscopy of complex organic molecules. In this talk, results will be presented from our studies using the Atacama Large Millimeter/submillimeter Array (ALMA) during the period 2012-2015, focussing in particular on the detection and mapping of emission from various nitrile species. By combining data from multiple ALMA observations, our spectra have reached an unprecedented sensitivity level, enabling the first spectroscopic detection and mapping of C2H3CN (vinyl cyanide) on Titan. Liquid-phase simulations of Titan's seas indicate that vinyl cyanide molecules could combine to form vesicle membranes (similar to the cells of terrestrial biology), and the astrobiological implications of this discovery will be discussed. Furthermore, ALMA observations provide instantaneous snapshot mapping of Titan's entire Earth-facing hemisphere, for gases inaccessible to previous instruments. Combined with complementary data obtained from the Cassini Saturn orbiter, as well as theoretical models and laboratory studies, our observed, seasonally variable, spatially resolved abundance patterns are capable of providing new insights into photochemical production and transport in primitive planetary atmospheres in the Solar System and beyond.

  13. Fog in the coastal region of southern Brazil: seasonal variations

    Science.gov (United States)

    Krusche, N.; Gomes, C.

    2009-05-01

    Fog forecasting, especially advection fog, is important because a large port is located at Rio Grande, 32° S and 52° W. Fogs discontinue the cargo transport and prevent entrance of ships in the port, causing great financial loss. Atmospheric and oceanographic conditions associated to fog formation are been investigated, especially those that happen during advection fog. The result of this characterization will facilitate the forecast using mesoscale numerical models. The research started with a climatology of fog in the region, in two locations which are 2° of latitude apart, with an average temperature difference of 3°C. The observation of fog is a standard record at conventional meteorological stations. Data from this study was obtained from the Meteorological Station of Rio Grande, which belongs to the Instituto Nacional de Meteorologia network, and from the Meteorological Station operated by the Division of Meteorology of Department of Airspace Control in Porto Alegre. The period of this study is from January 1990 to December 2005. The distribution of the monthly total of fog observations shows that they occur mainly between May and August, with maximum in June. In all seasons of the year the total number of fogs is greater than in Porto Alegre in Rio Grande. There was a decrease in the average annual number of fogs from the 90s to the last five years of research, which can be attributed to urbanization around the places of observation. It increases the temperature in the layers closer to the soil and decreases the available moisture, making the occurrence of radiation fog. Atmospheric and oceanographic conditions, prevalent during these occurrences, will be examined next. The another goal is to compare the data of advection fog in Rio Grande, obtained from images of the type ARGUS in Cassino beach, with those recorded by Meteorological Station. This work is partially financed by FINEP and CAPES.

  14. Seasonal variation of the single scattering albedo of the Jungfraujoch aerosol

    Energy Technology Data Exchange (ETDEWEB)

    Collaud Coen, M.; Weingartner, E.; Corrigan, C.; Baltensperger, U.

    2003-03-01

    The single scattering albedo ({omega}{sub 0}) represents the fraction of the light extinction due to scattering. It is there-fore a key parameter to estimate the aerosol direct radiative forcing. The seasonal and diurnal variation of the single scattering albedo was calculated for the Jungfraujoch dry aerosol, which is representative for clean remote continental conditions. The values of {omega}{sub 0} vary between 0.7 and 0.9 depending on the season and on the wavelength. (author)

  15. Seasonal Variations of Isotope Ratios and CO2 Concentrations in Firn Air

    OpenAIRE

    Weiler, Karin; Schwander, Jakob; Leuenberger, Markus; Blunier, Thomas; Mulvaney, Robert; Anderson, Philip S.; Salmon, Rhian; Sturges, William T.

    2009-01-01

    A first year-round firn air sampling carried out at the British Antarctic station Halley in 2003 shows isotope and CO2 changes owing to diffusive mixing driven by seasonal variations of surface temperature, and gas composition of the atmosphere. Seasonal firn temperatures are well reproduced from the atmospheric temperature history. Based on these profiles thermal diffusion is forced with thermal diffusion factors αT with respect to air. Application of the available literature data for αT (15...

  16. Seasonal variation of daily physical activity in individuals with heart failure

    Directory of Open Access Journals (Sweden)

    Michael J. Shoemaker

    2016-09-01

    Full Text Available BackgroundPrevious studies indicate that seasonal variation affects daily physical activity (PA, but none have investigated this relationship in individuals with heart failure (HF who also have implanted cardioverter defibrillators and cardiac resynchronization therapy (ICD/CRT devices. The purpose of the present study was to determine if seasonal variation in temperature affects daily PA in patients with HF and ICD/CRTs.Patients and methodsSecondary analysis of data from 16 subjects with HF and Medtronic® ICD/CRT devices enrolled in a randomized trial investigating interventions to improve daily PA. Due to the rolling study enrollment, daily PA data for all subjects were not available for the entire time frame and were divided into two groups. Determination of seasonal variation of daily PA was determined using visual analysis of daily PA plotted with average temperature, autocorrelation, visual analysis of seasonal subseries plots and boxplot analysis, as well as Wilcoxon signed-rank tests.ResultsSubjects 1-8 demonstrated the greatest differences in daily PA during periods of seasonal transition whereas subjects 9-16 demonstrated the greatest variation in daily PA with greatest seasonal temperature difference. Wilcoxon signed-rank testing of the lowest and highest months for daily PA revealed median differences of 0.30 (p = 0.050 and 0.36 hours (p = 0.036 for subjects 1-8 and 9-16, with effect sizes of 0.69 and 0.74, respectively.ConclusionsSeasonal variation in mean temperature appears to affect daily PA in individuals with HF and ICD/CRT devices by a magnitude of 0.30-0.36 hours, which may need to be accounted for in future research investigating interventions to improve daily PA.

  17. 20th-Century Climate Change over Africa: Seasonal Variation in Hydroclimate Trends and Sahara Desert Extent

    Science.gov (United States)

    Nigam, S.; Thomas, N. P.

    2017-12-01

    Twentieth-century trends in seasonal temperature and precipitation over the African continent are analyzed from observational data sets and historical climate simulations. Given the agricultural economy of the continent, a seasonal perspective is adopted as it is more pertinent than an annual-average one which can mask off-setting but agriculturally-sensitive seasonal hydroclimate variations. Examination of linear trends in seasonal surface air temperature (SAT) shows that heat stress has increased in several regions, including Sudan and Northern Africa where largest SAT trends occur in the warm season. Broadly speaking, the northern continent has warmed more than the southern one in all seasons. Precipitation trends are varied but notable declining trends are found in the countries along the Gulf of Guinea, especially in the source region of Niger river in West Africa, and in the Congo river basin. Rainfall over the African Great Lakes - one of the largest freshwater repositories - has however increased. We show that the Sahara Desert has expanded significantly over the 20th century - by 12-20% depending on the season. The desert expanded southward in summer, reflecting retreat of the northern edge of the Sahel rainfall belt; and to the north in winter, indicating potential impact of the widening of the Tropics. Specific mechanisms driving the expansion in each season are investigated. Finally, this observational analysis is used to evaluate the state-of-the-art climate models from a comparison of the 20th-century hydroclimate trends with those manifest in historical climate simulations. The evaluation shows that modeling regional hydroclimate change over the Africa continent remains challenging.

  18. Seasonal variation in internet keyword searches: a proxy assessment of sex mating behaviors.

    Science.gov (United States)

    Markey, Patrick M; Markey, Charlotte N

    2013-05-01

    The current study investigated seasonal variation in internet searches regarding sex and mating behaviors. Harmonic analyses were used to examine the seasonal trends of Google keyword searches during the past 5 years for topics related to pornography, prostitution, and mate-seeking. Results indicated a consistent 6-month harmonic cycle with the peaks of keyword searches related to sex and mating behaviors occurring most frequently during winter and early summer. Such results compliment past research that has found similar seasonal trends of births, sexually transmitted infections, condom sales, and abortions.

  19. Seasonal variations of vivax and falciparum malaria: an observation at a tertiary care hospital

    International Nuclear Information System (INIS)

    Jamil, S.; Khan, M.N.

    2012-01-01

    Background: Malaria is a major public health problem in the malaria endemic zones of the world. Various factors influence the prevalence of malaria. This study was conducted to determine the variation in frequency of Plasmodium vivax and Plasmodium falciparum malaria in different seasons of the year in Khyber Teaching Hospital, Peshawar. Methods: A total of 411 patients were included in the study. All these febrile patients were reported to have trophozoites of either Plasmodium vivax or Plasmodium falciparum malaria on Giemsa stained thick and thin smears. The frequency of vivax and falciparum malaria was worked out and statistically analysed for different season of the year. The study was carried out from 2nd Jan 2004 till 31st December 2008. Results: Out of total 411 diagnosed malaria cases, total 134 (32.60%) presented in the autumn season (vivax=33.58%, and falciparum=66.42%), 37 (9%) in winter season (vivax=32.4%, and falciparum=67.6%), 76 (18.49%) in spring season (vivax=93.4% and falciparum 6.6%) and 164 (39.90%) in summer season (vivax=89.6, and falciparum=10.4%). The malaria showed a highly significant pattern in different seasons of the year (p=0.00) in a way that Plasmodium falciparum malaria reached its highest frequency in autumn and winter seasons while Plasmodium vivax malaria reached its peak frequency in spring and summer seasons. Conclusion: There was highly significant seasonal variation of vivax and falciparum malaria. There is arrival of Plasmodium falciparum in autumn which peaks in winter followed by arrival of Plasmodium vivax in spring till the end of summer. (author)

  20. Lidar observed seasonal variation of vertical canopy structure in the Amazon evergreen forests

    Science.gov (United States)

    Tang, H.; Dubayah, R.

    2017-12-01

    Both light and water are important environmental factors governing tree growth. Responses of tropical forests to their changes are complicated and can vary substantially across different spatial and temporal scales. Of particular interest is the dry-season greening-up of Amazon forests, a phenomenon undergoing considerable debates whether it is real or a "light illusion" caused by artifacts of passive optical remote sensing techniques. Here we analyze seasonal dynamic patterns of vertical canopy structure in the Amazon forests using lidar observations from NASA's Ice, Cloud, and and land Elevation Satellite (ICESat). We found that the net greening of canopy layer coincides with the wet-to-dry transition period, and its net browning occurs mostly at the late dry season. The understory also shows a seasonal cycle, but with an opposite variation to canopy and minimal correlation to seasonal variations in rainfall or radiation. Our results further suggest a potential interaction between canopy layers in the light regime that can optimize the growth of Amazon forests during the dry season. This light regime variability that exists in both spatial and temporal domains can better reveal the dry-season greening-up phenomenon, which appears less obvious when treating the Amazon forests as a whole.

  1. Tropospheric methane in northern Finland: seasonal variations, transport patterns and correlations with other trace gases

    International Nuclear Information System (INIS)

    Aalto, Tuula; Hatakka, Juha; Lallo, Marko

    2007-01-01

    Methane mixing ratios have been continuously observed at Pallas, Finland since winter 2004. The seasonal variation in monthly means was ca. 40 ppb, showing largest mixing ratios in winter and also high values during late summer. Examination of back-trajectories showed that the air masses with elevated methane mixing ratios arrived from continental Eastern and Central Europe while low methane mixing ratios were connected with Atlantic and Arctic air masses. During summer, air masses with highest mixing ratios arrived from Northwestern Russia indicating wetland sources, while the influence of southern emissions became more significant in winter. Methane was positively correlated with carbon dioxide and negatively correlated with ozone in winter. The average slope of the selected wintertime background hourly mean mixing ratios was 7.0 ± 1.2 ppb(CH 4 )/ppm(CO 2 ). Nocturnal summertime low-altitude measurements above a local wetland source indicated slopes of about 10 ± 1 ppb(CH 4 )/ppm(CO 2 ). The different slopes reflect the differences in emission parameters

  2. Lack of seasonal variation in bone mass and biochemical estimates of bone turnover

    International Nuclear Information System (INIS)

    Overgaard, K.; Nilas, L.; Johansen, J.S.; Christiansen, C.

    1988-01-01

    Three previous studies have indicated a seasonal variation in bone mineral content, with values during the summer being 1.7% to 7.5% higher than during the winter. We have examined the seasonal influence on both bone mass, biochemical estimates of bone turnover and vitamin D metabolites in 86 healthy women, aged 29-53 years. All participants were followed up for 2 years with examinations every 6 weeks or 3 months. Bone mineral content in the proximal and distal part of the forearm (single photon absorptiometry) did not reveal any significant seasonal variation, whereas bone mineral density of the lumbar spine (dual photon absorptiometry) indicated that the highest values occurred in winter. None of the biochemical parameters showed any statistically significant cyclical changes. Serum concentrations of 25-hydroxyvitamin D and 24,25-dihydroxyvitamin D3 showed a highly significant seasonal variation, whereas the serum 1,25-dihydroxyvitamin D concentration was virtually unchanged. We conclude that seasonal variation in bone mineral content and bone turnover should not be taken into account when interpreting data from longitudinal studies of healthy pre- and postmenopausal women on a sufficient vitamin D nutriture

  3. Seasonal variation and light absorption property of carbonaceous aerosol in a typical glacier region of the southeastern Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    H. Niu

    2018-05-01

    Full Text Available Deposition and accumulation of light-absorbing carbonaceous aerosol on glacier surfaces can alter the energy balance of glaciers. In this study, 2 years (December 2014 to December 2016 of continuous observations of carbonaceous aerosols in the glacierized region of the Mt. Yulong and Ganhaizi (GHZ basin are analyzed. The average elemental carbon (EC and organic carbon (OC concentrations were 1.51±0.93 and 2.57±1.32 µg m−3, respectively. Although the annual mean OC ∕ EC ratio was 2.45±1.96, monthly mean EC concentrations during the post-monsoon season were even higher than OC in the high altitudes (approximately 5000 m a. s. l.  of Mt. Yulong. Strong photochemical reactions and local tourism activities were likely the main factors inducing high OC ∕ EC ratios in the Mt. Yulong region during the monsoon season. The mean mass absorption efficiency (MAE of EC, measured for the first time in Mt. Yulong, at 632 nm with a thermal-optical carbon analyzer using the filter-based method, was 6.82±0.73 m2 g−1, comparable with the results from other studies. Strong seasonal and spatial variations of EC MAE were largely related to the OC abundance. Source attribution analysis using a global aerosol–climate model, equipped with a black carbon (BC source tagging technique, suggests that East Asia emissions, including local sources, have the dominant contribution (over 50 % to annual mean near-surface BC in the Mt. Yulong area. There is also a strong seasonal variation in the regional source apportionment. South Asia has the largest contribution to near-surface BC during the pre-monsoon season, while East Asia dominates the monsoon season and post-monsoon season. Results in this study have great implications for accurately evaluating the influences of carbonaceous matter on glacial melting and water resource supply in glacierization areas.

  4. Seasonal variation and light absorption property of carbonaceous aerosol in a typical glacieri region of the southeastern Tibetan Plateau

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Hewen; Kang, Shichang; Wang, Hailong; Zhang, Rudong; Lu, Xixi; Qian, Yun; Paudyal, Rukumesh; Wang, Shijin; Shi, Xiaofei; Yan, Xingguo

    2018-05-07

    Deposition and accumulation of light-absorbing carbonaceous aerosol on glacier surfaces can alter the energy balance of glaciers. In this study, 2 years (December 2014 to December 2016) of continuous observations of carbonaceous aerosols in the glacierized region of the Mt. Yulong and Ganhaizi (GHZ) basin are analyzed. The average elemental carbon (EC) and organic carbon (OC) concentrations were 1.51±0.93 and 2.57±1.32 µg m−3, respectively. Although the annual mean OC ∕ EC ratio was 2.45±1.96, monthly mean EC concentrations during the post-monsoon season were even higher than OC in the high altitudes (approximately 5000 m a. s. l. ) of Mt. Yulong. Strong photochemical reactions and local tourism activities were likely the main factors inducing high OC ∕ EC ratios in the Mt. Yulong region during the monsoon season. The mean mass absorption efficiency (MAE) of EC, measured for the first time in Mt. Yulong, at 632 nm with a thermal-optical carbon analyzer using the filter-based method, was 6.82±0.73 m2 g−1, comparable with the results from other studies. Strong seasonal and spatial variations of EC MAE were largely related to the OC abundance. Source attribution analysis using a global aerosol–climate model, equipped with a black carbon (BC) source tagging technique, suggests that East Asia emissions, including local sources, have the dominant contribution (over 50 %) to annual mean near-surface BC in the Mt. Yulong area. There is also a strong seasonal variation in the regional source apportionment. South Asia has the largest contribution to near-surface BC during the pre-monsoon season, while East Asia dominates the monsoon season and post-monsoon season. Results in this study have great implications for accurately evaluating the influences of carbonaceous matter on glacial melting and water resource supply in glacierization areas.

  5. Spatiotemporal variations of ambient PM10 source contributions in Beijing in 2004 using positive matrix factorization

    Directory of Open Access Journals (Sweden)

    T. Chen

    2008-05-01

    Full Text Available Source contributions to ambient PM10 (particles with an aerodynamic diameter of 10 μm or less in Beijing, China were determined with positive matrix factorization (PMF based on ambient PM10 composition data including concentrations of organic carbon (OC, elemental carbon (EC, ions and metal elements, which were simultaneously obtained at six sites through January, April, July and October in 2004. Results from PMF indicated that seven major sources of ambient PM10 were urban fugitive dust, crustal soil, coal combustion, secondary sulfate, secondary nitrate, biomass burning with municipal incineration, and vehicle emission, respectively. In paticular, urban fugitive dust and crustal soil as two types of dust sources with similar chemical characteristics were differentiated by PMF. Urban fugitive dust contributed the most, accounting for 34.4% of total PM10 mass on an annual basis, with relatively high contributions in all four months, and even covered 50% in April. It also showed higher contributions in southwestern and southeastern areas than in central urban areas. Coal combustion was found to be the primary contributor in January, showing higher contributions in urban areas than in suburban areas with seasonal variation peaking in winter, which accounted for 15.5% of the annual average PM10 concentration. Secondary sulfate and secondary nitrate combined as the largest contributor to PM10 in July and October, with strong seasonal variation peaking in summer, accounting for 38.8% and 31.5% of the total PM10 mass in July and October, respectively. Biomass burning with municipal incineration contributions were found in all four months and accounted for 9.8% of the annual average PM10 mass concentration, with obviously higher contribution in October than in other months. Incineration sources were probably located in southwestern Beijing. Contribution from vehicle emission accounted for 5.0% and exhibited no significant seasonal variation. In sum

  6. Seasonal Variation in Vitamin D Status among Frail Older Hospitalized Patients.

    Science.gov (United States)

    Pourhassan, M; Wirth, R

    2018-01-01

    Seasonal variation in 25-hydroxyvitamin D [25(OH)D] levels is the result of sunlight dependent skin synthesis of vitamin D. However, its presence is not studied in frail older hospitalized patients. We sought to investigate whether seasonal variation in 25(OH)D levels is evident among these patients. This study investigated older participants who were consecutively admitted between February 2015 and December 2016 to the geriatric acute care ward. Results of routine measurements of 25(OH)D at hospital admission were retrospectively analyzed and stratified according to months and seasons. Previous intake of vitamin D supplementation was derived from the patients' medical records. The study group comprised 679 participants (mean age 82.1±8.2; 457 females), of which 78% had vitamin D deficiency. Older individuals not taking vitamin D supplements had a lower mean serum 25(OH)D than those receiving supplements. Of those patients with no vitamin D supplementation, 87.0% were vitamin D deficient and only 5% showing sufficient vitamin 25(OH)D. Further, there were neither monthly nor seasonal variations in vitamin 25(OH)D levels among these patients and their vitamin D levels stayed far below the recommended threshold of 20 ng/ml across the seasons. Vitamin D deficiency was very prevalent in the subgroup of older hospitalized patients without vitamin D supplementation, irrespective of season. Since no seasonal variations in mean 25(OH)D levels was observed, sunlight dependent skin synthesis is unlikely to contribute to vitamin D status in these patients. Supplementation seems to be necessary to maintain desirable vitamin D levels among this population throughout the year.

  7. Seasonal variations and air quality in Meknes city

    International Nuclear Information System (INIS)

    Ait Bouh, F.; Bounakhla, M.; Noack, Y.

    2008-01-01

    The automobile traffic and the terrigenous contributions are the two important sources of the air pollution in Meknes. This work is a study about gaseous pollution , particulate and metal in two sites with road traffics importants. Samples were carried out with devices like Gent, to separate a coarse fraction and thin fraction and an automatic analyzer of sulfur dioxide. The companions of samples took place from March to October 2007 at the FAR Avenue and from November 2007 to April 2008 at the Avenue Allal Ben Abdellah; six days for particulate matter and several days each month for sulfur dioxide. The collection period was 24 hours. The results of sulfur dioxide show very high concentrations during weekdays especially in peak hours. The maximum hourly, daily and monthly rates are important in July and August. And the average annual knows exceeded the annual quality objective set at 50ug / m 3 . In the case of particulate matter, the daily limit value (50 ug / m 3 ) and annual (40 ug / m 3 ) are exceeded on several occasions, compared with fine particles / total particulate generally quite low (below 0.5 ), showing the importance of terrigenous inputs and resuspension especially in July and August where the coarse fraction reached the highest levels. The heavy metals concentrations will be determined by X-ray fluorescence total reflection (TXRF) [fr

  8. Seasonal variations in glycemic control of type 2 diabetes in Korean women.

    Science.gov (United States)

    Ryu, Ohk-Hyun; Lee, Sungwha; Yoo, Hyung Joon; Choi, Moon-Gi

    2014-06-01

    Seasonal variations in lifestyle, such as food intake and physical activity, have been reported. Glycemic control in type 2 diabetes mellitus (T2DM) may be affected by such changes. We investigated seasonal variations in glycemic control, food intake, and physical activity in type 2 diabetic patients. This prospective observational study included 37 Korean female patients who had food intake (kcal/day), HbA1c, and anthropometry every 3 months (August, November, February, May, and August in the Northern Hemisphere) over 1 year. When anti-diabetic drugs were changed, we analyzed the data just before the changes. The mean HbA1c levels (%) of August and November in 2008, and February, May, and August in 2009 were 7.0 ± 0.1, 6.9 ± 0.1, 7.2 ± 0.2, 7.4 ± 0.2, and 7.2 ± 0.2, respectively (P = 0.018). The change of HbA1c was nearly 0.5 % for the 1-year period. From August to May of the following year, there were also seasonal variations in food intake (1,872 ± 143, 1,739 ± 97, 1,673 ± 86, 1,561 ± 132, respectively; P = 0.013), and total physical activity [7.7 (3.7-14.6), 6.3 (2.8-10.4), 5.1 (2.7-12.6), and 11.2 (4.7-20.5), respectively; P = 0.048]. However, the seasonal variations of HbA1c and total physical activity became non-significant when farmers were excluded. These data suggested that glycemic control, total physical activity, and food intake varied seasonally in Korean T2DM patients. These seasonal variations should be considered in education for glycemic control.

  9. Impacts of Land Cover and Seasonal Variation on Maximum Air Temperature Estimation Using MODIS Imagery

    Directory of Open Access Journals (Sweden)

    Yulin Cai

    2017-03-01

    Full Text Available Daily maximum surface air temperature (Tamax is a crucial factor for understanding complex land surface processes under rapid climate change. Remote detection of Tamax has widely relied on the empirical relationship between air temperature and land surface temperature (LST, a product derived from remote sensing. However, little is known about how such a relationship is affected by the high heterogeneity in landscapes and dynamics in seasonality. This study aims to advance our understanding of the roles of land cover and seasonal variation in the estimation of Tamax using the MODIS (Moderate Resolution Imaging Spectroradiometer LST product. We developed statistical models to link Tamax and LST in the middle and lower reaches of the Yangtze River in China for five major land-cover types (i.e., forest, shrub, water, impervious surface, cropland, and grassland and two seasons (i.e., growing season and non-growing season. Results show that the performance of modeling the Tamax-LST relationship was highly dependent on land cover and seasonal variation. Estimating Tamax over grasslands and water bodies achieved superior performance; while uncertainties were high over forested lands that contained extensive heterogeneity in species types, plant structure, and topography. We further found that all the land-cover specific models developed for the plant non-growing season outperformed the corresponding models developed for the growing season. Discrepancies in model performance mainly occurred in the vegetated areas (forest, cropland, and shrub, suggesting an important role of plant phenology in defining the statistical relationship between Tamax and LST. For impervious surfaces, the challenge of capturing the high spatial heterogeneity in urban settings using the low-resolution MODIS data made Tamax estimation a difficult task, which was especially true in the growing season.

  10. Latitudinal range influences the seasonal variation in the foraging behavior of marine top predators.

    Directory of Open Access Journals (Sweden)

    Stella Villegas-Amtmann

    Full Text Available Non-migratory resident species should be capable of modifying their foraging behavior to accommodate changes in prey abundance and availability associated with a changing environment. Populations that are better adapted to change will have higher foraging success and greater potential for survival in the face of climate change. We studied two species of resident central place foragers from temperate and equatorial regions with differing population trends and prey availability associated to season, the California sea lion (Zalophus californianus (CSL whose population is increasing and the endangered Galapagos sea lion (Zalophus wollebaeki (GSL whose population is declining. To determine their response to environmental change, we studied and compared their diving behavior using time-depth recorders and satellite location tags and their diet by measuring C and N isotope ratios during a warm and a cold season. Based on latitudinal differences in oceanographic productivity, we hypothesized that the seasonal variation in foraging behavior would differ for these two species. CSL exhibited greater seasonal variability in their foraging behavior as seen in changes to their diving behavior, foraging areas and diet between seasons. Conversely, GSL did not change their diving behavior between seasons, presenting three foraging strategies (shallow, deep and bottom divers during both. GSL exhibited greater dive and foraging effort than CSL. We suggest that during the warm and less productive season a greater range of foraging behaviors in CSL was associated with greater competition for prey, which relaxed during the cold season when resource availability was greater. GSL foraging specialization suggests that resources are limited throughout the year due to lower primary production and lower seasonal variation in productivity compared to CSL. These latitudinal differences influence their foraging success, pup survival and population growth reflected in

  11. Endogenous sources of variation in language acquisition.

    Science.gov (United States)

    Han, Chung-Hye; Musolino, Julien; Lidz, Jeffrey

    2016-01-26

    A fundamental question in the study of human language acquisition centers around apportioning explanatory force between the experience of the learner and the core knowledge that allows learners to represent that experience. We provide a previously unidentified kind of data identifying children's contribution to language acquisition. We identify one aspect of grammar that varies unpredictably across a population of speakers of what is ostensibly a single language. We further demonstrate that the grammatical knowledge of parents and their children is independent. The combination of unpredictable variation and parent-child independence suggests that the relevant structural feature is supplied by each learner independent of experience with the language. This structural feature is abstract because it controls variation in more than one construction. The particular case we examine is the position of the verb in the clause structure of Korean. Because Korean is a head-final language, evidence for the syntactic position of the verb is both rare and indirect. We show that (i) Korean speakers exhibit substantial variability regarding this aspect of the grammar, (ii) this variability is attested between speakers but not within a speaker, (iii) this variability controls interpretation in two surface constructions, and (iv) it is independent in parents and children. According to our findings, when the exposure language is compatible with multiple grammars, learners acquire a single systematic grammar. Our observation that children and their parents vary independently suggests that the choice of grammar is driven in part by a process operating internal to individual learners.

  12. Seasonal Characteristics of Widespread Ozone Pollution in China and India: Current Model Capabilities and Source Attributions

    Science.gov (United States)

    Gao, M.; Song, S.; Beig, G.; Zhang, H.; Hu, J.; Ying, Q.; McElroy, M. B.

    2017-12-01

    Fast urbanization and industrialization in China and India have led to severe ozone pollution, threatening public health in these densely populated countries. We show the spatial and seasonal characteristics of ozone concentrations using nation-wide observations for these two countries in 2013. We used the Weather Research and Forecasting model coupled to chemistry (WRF-Chem) to conduct one-year simulations and to evaluate how current models capture the important photochemical processes using the exhaustive available datasets in China and India, including surface measurements, ozonesonde data and satellite retrievals. We also employed the factor separation approach to distinguish the contributions of different sectors to ozone during different seasons. The back trajectory model FLEXPART was applied to investigate the role of transport in highly polluted regions (e.g., North China Plain, Yangtze River delta, and Pearl River Delta) during different seasons. Preliminary results indicate that the WRF-Chem model provides a satisfactory representation of the temporal and spatial variations of ozone for both China and India. The factor separation approach offers valuable insights into relevant sources of ozone for both countries providing valuable guidance for policy options designed to mitigate the related problem.

  13. Seasonal variations of the high-latitude geomagnetic field intensity in the northern hemisphere

    International Nuclear Information System (INIS)

    Rivin, Yu.R.; Chkhaidze, Z.Sh.

    1994-01-01

    Seasonal variation of the geomagnetic field three components is investigated using the data of the USA observatories chain separately for polar region, auroral zone and middle latitudes beginning from 1950. The variation consists of an annual and half-yearly waves. main attention is paid to time variability of the annual wave phase in the auroral zone, that is connected with superposition of waves of western and eastern jets

  14. Seasonal and diurnal variations of ocular pressure in ocular hypertensive subjects in Pakistan.

    Science.gov (United States)

    Qureshi, I A; Xiao, R X; Yang, B H; Zhang, J; Xiang, D W; Hui, J L

    1999-05-01

    Studies have been shown that intraocular pressure (IOP) shows a diurnal variation in ocular hypertensive subjects, but the amount of change differs from study to study. In recent years it has been noted that intraocular pressure is a dynamic function and is subjected to many influences both acutely and over the long term. The variability in the results may be due to negligence of factors that can affect IOP. Moreover, seasonal variations in the ocular hypertensive subjects have never been described. After placing control on those factors that can affect IOP, this study investigated seasonal and diurnal variations in IOP of ocular hypertensive subjects. IOP was measured each month over the course of 12 months with the Goldmann applanation tonometer in 91 ocular hypertensive male subjects. To see the diurnal changes, subjects were asked to stay in the hospital for 24 hours. The average IOP in the winter months was higher than those in spring, summer, and autumn. The IOP difference between winter and summer was (mean +/- sem) 2.9 +/- 0.9 mmHg (p < 0.001). The peak of mean IOP in diurnal variation curve (25.7 +/- 1.2 mmHg) appeared in the morning when the subjects had just awaken. The mean diurnal variation was found to be 4.2 +/- 0.6 mmHg (p < 0.001). This study confirms that seasons influence IOP and it shows diurnal variations. As compared to other nations, diurnal variations in ocular hypertensive subjects seem to be somewhat less in Pakistan. Knowledge of the seasonal and diurnal variations in IOP may help glaucoma screeners.

  15. Seasonal variation of ice melting on varying layers of debris of Lirung Glacier, Langtang Valley, Nepal

    Directory of Open Access Journals (Sweden)

    M. B. Chand

    2015-05-01

    Full Text Available Glaciers in the Himalayan region are often covered by extensive debris cover in ablation areas, hence it is essential to assess the effect of debris on glacier ice melt. Seasonal melting of ice beneath different thicknesses of debris on Lirung Glacier in Langtang Valley, Nepal, was studied during three seasons of 2013–14. The melting rates of ice under 5 cm debris thickness are 3.52, 0.09, and 0.85 cm d−1 during the monsoon, winter and pre-monsoon season, respectively. Maximum melting is observed in dirty ice (0.3 cm debris thickness and the rate decreases with the increase of debris thickness. The energy balance calculations on dirty ice and at 40 cm debris thickness show that the main energy source of ablation is net radiation. The major finding from this study is that the maximum melting occurs during the monsoon season than rest of the seasons.

  16. Seasonal variation of fatty acids from drip water in Heshang Cave, central China

    International Nuclear Information System (INIS)

    Li Xiuli; Wang Canfa; Huang Junhua; Hu Chaoyong; Xie Shucheng

    2011-01-01

    Research highlights: → A 2-year monitoring to investigate the seasonal variation of fatty acids in cave drip water. → Microbes are the dominant source for fatty acids in drip water. → The relative abundance of mono-unsaturated responds negatively with external air temperature. - Abstract: In order to investigate how lipids in cave water respond to seasonal climate change, drip water samples were collected from 2006 to 2008 in Heshang Cave, central China for fatty acid analysis. These lipids are abundant in the drip water. Their compositions are dominated by lower-molecular-weight nC16:0, nC18:0 and nC14:0 acids, together with mono-unsaturated nC18:1, nC16:1 and nC14:1. Analysis of one water sample revealed marked differences between the dissolved and particulate fractions. The dissolved fraction contains total fatty acids one order of magnitude higher than that of the particulate fraction. The distributional patterns of the fatty acids suggest that microbes living in the overlying soils and/or groundwater system contribute most fatty acids to the drip water. This 2-a monitoring experiment reveals that the abundance of mono-unsaturated fatty acids relative to the saturated homologues (nC16:1/nC16:0 and nC18:1/nC18:0) relate inversely to the changes of synchronous external air temperature. Higher values occur under cold conditions (winter/spring), while lower values appear in warm intervals (summer). Further studies are needed to elucidate the dynamic processes by which the external temperature affects fatty acids in drip water and to confirm the potential application of fatty acid ratios such as nC16:1/nC16:0 and nC18:1/nC18:0 in paleotemperature reconstructions.

  17. Comparison of seasonal variation between anthropogenic and natural emission inventory and Satellite observation in Southeast Asia

    Science.gov (United States)

    Kurata, G.; Lalitaporn, P.

    2012-12-01

    Since the economic growth of the countries in Southeast Asia is significantly rapid, the emission of air pollutant from the anthropogenic activity, such as industry, power generation and transportation is rapidly increasing. Moreover, biomass burning due to unsuitable agricultural management, deforestation and expansion of farmland are discharging large amount of pollutants, such as Carbon monoxide, volatile organic compound and particulate matter. Especially, the particulate matter from biomass burning causes the serious haze pollution in surrounding area in Southeast Asia. Furthermore, the biomass fuel used for cooking at residential sector discharges harmful pollutants including a particulate matter, and causes the adverse health impact to people on indoor and outdoor. In this study, we evaluated the spatial distribution and the seasonal variation of emission inventory for Southeast Asia region by comparing with satellite observation data in order to improve the accuracy of the impact assessment of air pollution by regional atmospheric chemistry transport model (WRF and CMAQ). As an emission inventory data, we used our original regional emission inventory for Southeast Asia region developed from detail transportation and industry data sets as well as a several existing emission inventories. As satellite observation data, the vertical column density of NO2, Particulate matter and Carbon monoxide obtained by various satellite, such as GOME, GOME2, SCIAMACY, OMI and so on. As a result of comparisons between satellite observation and emission inventories from 1996 to 2011, in the case of anthropogenic emission, seasonal variation was comparatively well in agreement with the seasonal variation of satellite data. However, the uncertainty of the seasonal variation was large on several large cities. In the case of emission from biomass burning, the seasonal variation was clear, but inter-annual variation was also large due to large scale climate condition.

  18. Seasonal variation in thoracic vessel calcifications: Evidence from a chest computed tomography study

    Energy Technology Data Exchange (ETDEWEB)

    Vehmas, Tapio; Leino-Arjas, Paeivi (Health and Work Ability, Finnish Inst. of Occupational Health, Helsinki (Finland)), e-mail: tapio.vehmas@ttl.fi; Hiltunen, Asta (Dept. of Radiology, Central Hospital of Laensi-Pohja, Kemi (Finland))

    2010-01-15

    Background: Cardiovascular disease incidence and mortality exhibit a winter peak and a summer trough, a fact that could have radiological manifestations. Purpose: To identify possible seasonal trends in the occurrence of thoracic vessel calcifications. Material and Methods: 505 male construction workers (aged 39-80 years) were each imaged once with chest spiral computed tomography (CT) during a 2-year period. Based on visual assessment of calcified plaques (0=no, 1=slight, 2=moderate, 3=extensive calcification), sum scores of atherosclerosis in coronary arteries, in the thoracic aorta, in the pre-cervical artery bases, and overall were constructed. The scores were regressed on the annual rank number of the CT day. Results: By using the cubic regression model, seasonal variation in calcified plaques in coronary arteries (P=0.003), in pre-cervical artery origins (P=0.015), and in the overall sum score (P=0.004) was observed. The peak occurred in January-February and the nadir in August. Depending on the model, about 2-3% of the variation in atherosclerotic calcifications could be explained by the season of imaging. Conclusion: The observed seasonal trend in calcifications parallels with mortality reports. Seasonal variations should be considered in atherosclerosis treatment studies. Confirmatory studies using modern imaging technology are needed in different countries and geographical locations, preferably with repeat imaging of the same individuals

  19. Seasonal variation of semidiurnal internal tides in the East/Japan Sea

    Science.gov (United States)

    Jeon, Chanhyung; Park, Jae-Hun; Varlamov, Sergey M.; Yoon, Jong-Hwan; Kim, Young Ho; Seo, Seongbong; Park, Young-Gyu; Min, Hong Sik; Lee, Jae Hak; Kim, Cheol-Ho

    2014-05-01

    The seasonal variation of semidiurnal internal tides in the East/Japan Sea was investigated using 25 month long output from a real-time ocean forecasting system. The z coordinate eddy-resolving high-resolution numerical model, called the RIAM ocean model, incorporates data assimilation that nudges temperature and salinity fields together with volume transport through the Korea Strait to produce realistic oceanic currents and stratification. In addition to atmospheric forcing, it includes tidal forcing of 16 major components along open boundaries. The model generates energetic semidiurnal internal tides around the northern entrance of the Korea Strait. Energy conversion from barotropic to baroclinic (internal) tides varies seasonally with maxima in September (ranging 0.48-0.52 GW) and minima in March (ranging 0.11-0.16 GW). This seasonal variation is induced by the seasonality in stratification near the southwestern East/Japan Sea. The propagation distance of the internal tides is associated with generation intensity and wavelength. From late summer to early winter, the semidiurnal internal tides travel relatively far from the generation region due to stratification changes; its energy dissipates less as a result of longer wavelengths. Our results suggest that spatiotemporal variation of internal-tide-induced mixing due to the seasonality in the generation, propagation, and dissipation of internal tides should be considered for a more realistic simulation of water masses and circulation in models of the East/Japan Sea.

  20. Seasonal variation of deep-sea bioluminescence in the Ionian Sea

    International Nuclear Information System (INIS)

    Craig, Jessica; Jamieson, Alan J.; Bagley, Philip M.; Priede, Imants G.

    2011-01-01

    The ICDeep (Image Intensified Charge Coupled Device for Deep sea research) profiler was used to measure the density of deep bioluminescent animals (BL) through the water column in the east, west and mid-Ionian Sea and in the Algerian Basin. A west to east decrease in BL density was found. Generalized additive modelling was used to investigate seasonal variation in the east and west Ionian Sea (NESTOR and NEMO neutrino telescope sites, respectively) from BL measurements in autumn 2008 and spring 2009. A significant seasonal effect was found in the west Ionian Sea (p<0.001), where a deep autumnal peak in BL density occurred between 500 and 2400 m. No significant seasonal variation in BL density was found in the east Ionian Sea (p=0.07). In both spring and autumn, significant differences in BL density were found through the water column between the east and west Ionian Sea (p<0.001).

  1. Seasonal variation of deep-sea bioluminescence in the Ionian Sea

    Energy Technology Data Exchange (ETDEWEB)

    Craig, Jessica, E-mail: j.craig@abdn.ac.u [University of Aberdeen, Oceanlab, Main Street, Newburgh, Aberdeenshire, AB41 6AA (United Kingdom); Jamieson, Alan J.; Bagley, Philip M.; Priede, Imants G. [University of Aberdeen, Oceanlab, Main Street, Newburgh, Aberdeenshire, AB41 6AA (United Kingdom)

    2011-01-21

    The ICDeep (Image Intensified Charge Coupled Device for Deep sea research) profiler was used to measure the density of deep bioluminescent animals (BL) through the water column in the east, west and mid-Ionian Sea and in the Algerian Basin. A west to east decrease in BL density was found. Generalized additive modelling was used to investigate seasonal variation in the east and west Ionian Sea (NESTOR and NEMO neutrino telescope sites, respectively) from BL measurements in autumn 2008 and spring 2009. A significant seasonal effect was found in the west Ionian Sea (p<0.001), where a deep autumnal peak in BL density occurred between 500 and 2400 m. No significant seasonal variation in BL density was found in the east Ionian Sea (p=0.07). In both spring and autumn, significant differences in BL density were found through the water column between the east and west Ionian Sea (p<0.001).

  2. Seasonal Variation in Monthly Average Air Change Rates Using Passive Tracer Gas Measurements

    DEFF Research Database (Denmark)

    Frederiksen, Marie; Bergsøe, Niels Christian; Kolarik, Barbara

    2011-01-01

    in five dwellings in Greater Copenhagen, Denmark. A passive tracer gas technique (Perfluorocarbon) was used to measure ACR in a seven-month period. Considerable differences were observed between the dwellings with monthly ACRs ranging from 0.21 to 1.75 h-1. Only smaller seasonal variations, generally less...... driving forces for natural ventilation is partially compensated by changed occupant behaviour....

  3. Estimating seasonal variations in cloud droplet number concentration over the boreal forest from satellite observations

    NARCIS (Netherlands)

    Janssen, R.; Ganzeveld, L.N.; Kabat, P.; Kulmala, M.; Nieminen, T.; Roebeling, R.A.

    2011-01-01

    Seasonal variations in cloud droplet number concentration (NCD) in low-level stratiform clouds over the boreal forest are estimated from MODIS observations of cloud optical and microphysical properties, using a sub-adiabatic cloud model to interpret vertical profiles of cloud properties. An

  4. Seasonal variation in short-term mortality after surgery for colorectal cancer?

    DEFF Research Database (Denmark)

    Iversen, L H; Nielsen, H; Pedersen, L

    2010-01-01

    Comorbidity has a major impact on short-term and long-term survival of colorectal cancer (CRC) and many CRC patients suffer from comorbidities. Mortality rates for comorbidities like cardio-respiratory diseases exhibit distinct seasonal variations with highest rates in the winter. Therefore, we...

  5. Seasonal variation in soil and plant water potentials in a Bolivian tropical moist and dry forest

    NARCIS (Netherlands)

    Markesteijn, L.; Iraipi, J.; Bongers, F.; Poorter, L.

    2010-01-01

    We determined seasonal variation in soil matric potentials (¿soil) along a topographical gradient and with soil depth in a Bolivian tropical dry (1160 mm y-1 rain) and moist forest (1580 mm y-1). In each forest we analysed the effect of drought on predawn leaf water potentials (¿pd) and drought

  6. Variations of streambed vertical hydraulic conductivity before and after a flood season

    Science.gov (United States)

    Wu, Guangdong; Shu, Longcang; Lu, Chengpeng; Chen, Xunhong; Zhang, Xiao; Appiah-Adjei, Emmanuel K.; Zhu, Jingsi

    2015-11-01

    The change of vertical hydraulic conductivity ( K v) before and after a flood season is crucial in understanding the long-term temporal variation of streambed permeability. Therefore, in this study, a detailed K v field investigation was conducted at an in-channel site within the Dawen River, China, before and after a flood season. In-situ falling-head permeameter tests were performed for the determination of K v. The tests were conducted using a 10 × 10 grid, at five different depths. In total, 871 valid K v values from layers 1-5 were obtained. The Kruskal-Wallis test on these K v values before and after the flood season shows they belonged to different populations. The sediments before the flood season primarily consisted of sand and gravel, whereas after the flood season, patchy distribution of silt/clay occurred in the sandy streambed and silt/clay content increased with the increasing depth; under the losing condition during flooding, downward movement of water brought fine particles into the coarse sediments, partially silting the pores. Accordingly, the K v values after the flood season had a smaller mean and median, and a higher level of heterogeneity, compared to those before the flood season. Additionally, the distribution pattern in K v across the stream differed before and after flood season; after the flood season, there was an increasing trend in K v from the south bank to the north bank. Overall, the contrasts of K v before and after the flood season were predominantly subject to the infiltration of fine particles.

  7. Seasonal variation in the composition and concentration of butyltin compounds in marine fish of Taiwan

    International Nuclear Information System (INIS)

    Dong, C.D.; Chen, C.W.; Liu, L.L.

    2004-01-01

    For the first time, strong evidence is presented to demonstrate that the accumulations of butyltin compounds (BTs) exhibit seasonal variations with respect to their compositions and concentrations in marine fishes. Measurements were made on the benthic ponyfish Leiogenathus splendens and lizardfish Trachinocephalus myops inhabiting the west coast of Taiwan. In the whole body samples of the ponyfish, BT concentrations ranged from 236 to 2501 ng/g wet wt, with those in winter considerably higher than in the other seasons (p summer > spring (p<0.05). Meanwhile, TBT (41%) was predominant in spring, whereas DBT (50 and 68%) was most heavily concentrated in summer and autumn (p<0.001). Seasonally mediated physiological changes, such as dilution due to growth and metabolic compensation, may play important roles in forming different BT accumulation patterns among seasons and organisms

  8. Evolution of Mars’ Northern Polar Seasonal CO2 deposits: variations in surface brightness and bulk density

    Science.gov (United States)

    Mount, Christopher P.; Titus, Timothy N.

    2015-01-01

    Small scale variations of seasonal ice are explored at different geomorphic units on the Northern Polar Seasonal Cap (NPSC). We use seasonal rock shadow measurements, combined with visible and thermal observations, to calculate density over time. The coupling of volume density and albedo allows us to determine the microphysical state of the seasonal CO2 ice. We find two distinct endmembers across the NPSC: 1) Snow deposits may anneal to form an overlying slab layer that fractures. These low density deposits maintain relatively constant densities over springtime. 2) Porous slab deposits likely anneal rapidly in early spring and fracture in late spring. These high density deposits dramatically increase in density over time. The endmembers appear to be correlated with latitude.

  9. Variation in the serum bilirubin levels in newborns according to gender and seasonal changes

    Directory of Open Access Journals (Sweden)

    Jyoti Bala

    2015-01-01

    Full Text Available Introduction: Bilirubin is a substance that is produced during the process of hemolysis. Gender influences on neonatal illnesses and outcomes have remained a topic of debate and investigation. Empirical neonatological experience suggests that prevalence and degree of neonatal jaundice might be dependent on seasonal variation also. The aim of our study is to interpret the bilirubin levels in newborns according to gender and seasonal variation. Materials and Methods: The study was done from October 2012 to July of 2013 (differentiated by seasonal variation. A total of 1000 jaundiced newborn (500 of each sex diagnosed clinically and divided equally in summer and winter season were studied to assess the total, direct and indirect serum bilirubin levels using colorimetry. Results: Out of total 1676 deliveries (439 were caesarean, 13 were assisted and rest were normal during winter season and 1475 deliveries (399 were Cesarean, 14 were assisted and rest were normal during summer season, 500 male newborn and 500 female newborn were analysed, divided equally in both seasons. Serum bilirubin was higher in males in summers and mainly comprised unconjugated bilirubin while direct bilirubin was higher in females in winters. Raised indirect bilirubin was more common in males born in summer than those born in winters (P = 041. In winters raised direct bilirubin was more common in females as compared to males (P = 0.019. Among female neonates total and indirect bilirubin was significantly raised in those born in summers (P = < 0.001 and <0.001, respectively while direct was raised in those born in winters (P = 0.003. Conclusion: Physiological and pathologic phenomena associated with male gender must be integrated in the frame of understanding of both susceptibility and protection of the male newborn which has not been available for adequate investigation in the past. The higher temperature during the summer, with a greater influence of higher breastfeeding

  10. Seasonal variations of CO2 and 222Rn in a mediterranean sinkhole - spring (Causse d’Aumelas, SE France

    Directory of Open Access Journals (Sweden)

    Batiot-Guilhe Christelle

    2007-01-01

    Full Text Available Carbon dioxide and 222Rn monitoring of the atmosphere of a Mediterranean sink hole - spring (SE France during two hydrological cycles (from September 2004 to September 2006 showed seasonal variations with very high concentrations during summer (greater than 6% and 20 000 Bq/m3, respectively. Gas dynamics in caves often show seasonal variations.Meteorological parameters (barometric pressure and temperature mainly, cave geometry and fracture networks control exchanges between the cavity and outside atmosphere. Carbon dioxide and 222Rn may have different sources (atmosphere, soil, bedrock, deep gas diffusion, in situ oxidation of organic matter and, in some caves, the key role of swift underground streams.For a CO2 origin, 13C measurements on water and gas samples taken into the cavity suggest a superficial origin. Radon-222 appears to be locally produced and transported by biogenic CO2. Further investigations will be carried out in order to study the relationship of gas-level variations with barometric pressure variations and piezometric level fluctuations within the aquifer.

  11. [Seasonal variation in the absorption and fluorescence characteristics of CDOM in downstream of Liaohe River].

    Science.gov (United States)

    Shao, Tian-Tian; Zhao, Ying; Song, Kai-Shan; Du, Jia; Ding, Zhi

    2014-10-01

    Chromophoric dissolved organic matter (CDOM), which is an important part of dissolved organic matter (DOM), is considered as the largest storage of dissolved organic carbon in the aquatic environment. Liaohe River is the seventh largest river in China with annual runoff of 1.48 billion m3. As a result, studying on CDOM of Liaohe River is very important in estimating the organic carbon flux into sea. Seasonal optical characteristics of CDOM in the downstream of Liaohe River were investigated using absorbance spectroscopy and fluorescence excitation-emission matrices (EEMs). CDOM absorption coefficient at 355 nm [aCDOM (355)] in spring was lower than that in autumn and winter while low molecular weight substances were found in autumn and high molecular weight substances in spring based on the absorption coefficient and absorption slope (S) of CDOM. Samples in different seasons all exhibited fairly strong protein-like fluorophore (fluorophore B and fluorophore T) in the EEMs but the values showed apparent temporal variations. Based on the analysis of the relationships between different fluorophores, strong correlations (R2 > 0. 9) were observed between fluorophore A and C in spring, fluorophore B and T in autumn and winter, which illustrated that they had similar CDOM originalsources. However, a weak relationship (R2 = 0.21) was found between fluorophore B and T in spring, demonstrating the complexity and diversity of CDOM sources. Starting from autumn to winter and the subsequent spring, humic-like fluorophores exhibited enhanced fluorescent intensity, which could be ascribed to exogenous input. Furthermore, linear relationship between aCDOM (355) and Fn (355) in different seasons was examined in the study, and the strongest relationship was obtained in winter (R2 = 0.75), followed by autumn (R2 = 0.48) and spring (R2 = 0.01). This study indicated that fluorophore B in autumn and winter (R = 0.66; R = 0.89) as well as humic-like fluorophores (A and C, R = 0.74; R = 0

  12. Seasonal variation of CO{sub 2} flux between air and temperate forest

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Susumo; Murayama, Shohei; Kondo, Hiroaki [National Inst. for Resources and Environment, Ibaraki (Japan)

    1995-12-31

    Carbon dioxide, which is a very important greenhouse gas, contributes approximately 55 % to the problem of global warming. The knowledge to the sources and sinks of carbon on a global basis is very poor. IPCC (1994) suggested that unknown 1.5-2.0 GtC/year may be sunk in terrestrial ecosystem, in particular, in the Northern Hemisphere. As can be seen from a recent estimation of the carbon fluxes in the terrestrial biosphere, there is a high degree of uncertainty in the magnitude. The clear evidence for it has not been shown yet by IPCC (1994). However, based on the gradient of CO{sub 2}, as a function of latitude, main CO{sub 2} sink can be thought to be in the terrestrial biosphere, in the middle to high latitude of the Northern Hemisphere. As can be seen from a recent estimation of the carbon fluxes in the terrestrial biosphere, there is a high degree of uncertainty in the magnitude. From this view, more investigation of the role of the temperate forest on the CO{sub 2} balance is inevitable. In this presentation, the seasonal variation of CO{sub 2} flux between air and biosphere in temperate deciduous forest in Japan is intended to be elucidated. (author)

  13. Molecular composition and seasonal variation of amino acids in urban aerosols from Beijing, China

    Science.gov (United States)

    Ren, Lujie; Bai, Huahua; Yu, Xi; Wu, Fengchang; Yue, Siyao; Ren, Hong; Li, Linjie; Lai, Senchao; Sun, Yele; Wang, Zifa; Fu, Pingqing

    2018-05-01

    Fifteen hydrolyzed amino acids (THAA) were quantified in urban aerosols (TSP samples) collected during April 2012 to May 2013 in Beijing, China using high-performance liquid chromatography (HPLC) after their derivatization with o-phthalaldehyde (OPA), to investigate their molecular distributions and seasonal variation. Total concentrations of amino acids ranged from 1.73-25.7 nmol m- 3 with a peak in spring (13.7 nmol m- 3), followed by winter (11.5 nmol m- 3), fall (9.51 nmol m- 3) and summer (7.45 nmol m- 3). Glycine (Gly), alanine (Ala) and valine (Val) are found to be the most abundant species, which account for 46% of the total THAA. Compared with those recorded in previous studies, the atmospheric levels of amino acids in Beijing were higher than those from other regions. Enhanced amounts of methionine, tyrosine, histidine, aspartic acid and glutamic acid were found during the rainfall events. The factor analysis further suggests that amino acids in urban Beijing originated from multiple sources including biological emission, biomass burning, as well as anthropogenic activities.

  14. Seasonal variation of CO{sub 2} flux between air and temperate forest

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Susumo; Murayama, Shohei; Kondo, Hiroaki [National Inst. for Resources and Environment, Ibaraki (Japan)

    1996-12-31

    Carbon dioxide, which is a very important greenhouse gas, contributes approximately 55 % to the problem of global warming. The knowledge to the sources and sinks of carbon on a global basis is very poor. IPCC (1994) suggested that unknown 1.5-2.0 GtC/year may be sunk in terrestrial ecosystem, in particular, in the Northern Hemisphere. As can be seen from a recent estimation of the carbon fluxes in the terrestrial biosphere, there is a high degree of uncertainty in the magnitude. The clear evidence for it has not been shown yet by IPCC (1994). However, based on the gradient of CO{sub 2}, as a function of latitude, main CO{sub 2} sink can be thought to be in the terrestrial biosphere, in the middle to high latitude of the Northern Hemisphere. As can be seen from a recent estimation of the carbon fluxes in the terrestrial biosphere, there is a high degree of uncertainty in the magnitude. From this view, more investigation of the role of the temperate forest on the CO{sub 2} balance is inevitable. In this presentation, the seasonal variation of CO{sub 2} flux between air and biosphere in temperate deciduous forest in Japan is intended to be elucidated. (author)

  15. PATIENT DEMOGRAPHIC, RISK FACTORS AND SEASONAL VARIATION IN ONSET OF STROKE

    Directory of Open Access Journals (Sweden)

    M. K. M. Kathyayani

    2016-10-01

    Full Text Available BACKGROUND Existence of particular chronobiological pattern in onset of acute cerebrovascular diseases characterised by circannual rhythms has been detected. India is a subtropical country with clear seasonal variations in weather conditions. Stroke causes death and disability worldwide. Seasons may influence stroke occurrence. The mechanisms underlying these seasonal variations of stroke are not fully understood, but a possible reason may include seasonal variation of biological factors such as arterial blood pressure, serum lipid levels and other blood components. Better understanding and controlling of risk factors associated with onset of stroke will improve the disease prevention. The objective of the present study is to examine the role of possible precipitating or triggering factors. This study reviews records of patients with stroke attending the Department of Medicine, KGH, Visakhapatnam. MATERIALS AND METHODS Patients with diagnosis of stroke attending the Department of Medicine, KGH, Visakhapatnam, were selected. Computed tomographic types of stroke, both ischaemic and haemorrhagic and risk factors associated were considered with tropical seasonal variation. RESULTS A total of 150 stroke patients were included in the study of which 93 (62% were males, 57 (38% were females and 46% in 50-65 years age group, 4% in 20-35 years, 28% in 35-50 years, 22% in 65-80 years and above age groups. Of the total, 93.33% presented with 1st attack and only 6.66% presented with recurrent stroke. The prevalence of types of stroke was: ischaemic stroke 54.66%, haemorrhagic stroke 45.33%. The prevalence of risk factors associated with stroke was - male gender 62%, smoking 56.66%, hypertension 56%, age >50 years 46%, alcohol consumption 43%, hyperlipidaemia 16.66%, consumption of alcohol and smoking together 13.33%, valvular heart diseases 6.66%. A high seasonal prevalence was observed in winter season (50.66%. CONCLUSION This study revealed that male

  16. Seasonal variations of thermocline circulation and ventilation in the Indian Ocean

    Science.gov (United States)

    You, Yuzhu

    1997-05-01

    Two seasonal hydrographic data sets, including temperature, salinity, dissolved oxygen, and nutrients, are used in a mixing model which combines cluster analysis with optimum multiparameter analysis to determine the spreading and mixing of the thermocline waters in the Indian Ocean. The mixing model comprises a system of four major source water masses, which were identified in the thermocline through cluster analysis. They are Indian Central Water (ICW), North Indian Central Water (NICW) interpreted as aged ICW, Australasian Mediterranean Water (AAMW), and Red Sea Water (RSW)/Persian Gulf Water (PGW). The mixing ratios of these water masses are quantified and mapped on four isopycnal surfaces which span the thermocline from 150 to 600 m in the northern Indian Ocean, on two meridional sections along 60°E and 90°E, and on two zonal sections along 10°S and 6°N. The mixing ratios and pathways of the thermocline water masses show large seasonal variations, particularly in the upper 400-500 m of the thermocline. The most prominent signal of seasonal variation occurs in the Somali Current, the western boundary current, which appears only during the SW (summer) monsoon. The northward spreading of ICW into the equatorial and northern Indian Ocean is by way of the Somali Current centered at 300-400 m on the σθ=26.7 isopycnal surface during the summer monsoon and of the Equatorial Countercurrent during the NE (winter) monsoon. More ICW carried into the northern Indian Ocean during the summer monsoon is seen clearly in the zonal section along 6°N. NICW spreads southward through the western Indian Ocean and is stronger during the winter monsoon. AAMW appears in both seasons but is slightly stronger during the summer in the upper thermocline. The westward flow of AAMW is by way of the South Equatorial Current and slightly bends to the north on the σθ=26.7 isopycnal surface during the summer monsoon, indicative of its contribution to the western boundary current. Outflow

  17. Impact of seasonal variation on Escherichia coli concentrations in the riverbed sediments in the Apies River, South Africa.

    Science.gov (United States)

    Abia, Akebe Luther King; Ubomba-Jaswa, Eunice; Momba, Maggy Ndombo Benteke

    2015-12-15

    Many South Africans living in resource-poor settings with little or no access to pipe-borne water still rely on rivers as alternative water sources for drinking and other purposes. The poor microbial quality of such water bodies calls for appropriate monitoring. However, routine monitoring only takes into consideration the microbial quality of the water column, and does not include monitoring of the riverbed sediments for microbial pollution. This study sought to investigate the microbial quality of riverbed sediments in the Apies River, Gauteng Province, South Africa, using Escherichia coli as a faecal indicator organism and to investigate the impact of seasonal variation on its abundance. Weekly samples were collected at 10 sampling sites on the Apies River between May and August 2013 (dry season) and between January and February 2014 (wet season). E. coli was enumerated using the Colilert®-18 Quanti-Tray® 2000 system. All sites tested positive for E. coli. Wastewater treatment work effluents had the highest negative impact on the river water quality. Seasonal variations had an impact on the concentration of E. coli both in water and sediments with concentrations increasing during the wet season. A strong positive correlation was observed between temperature and the E. coli concentrations. We therefore conclude that the sediments of the Apies River are heavily polluted with faecal indicator bacteria and could also harbour other microorganisms including pathogens. The release of such pathogens into the water column as a result of the resuspension of sediments due to extreme events like floods or human activities could increase the health risk of the populations using the untreated river water for recreation and other household purposes. There is therefore an urgent need to reconsider and review the current South African guidelines for water quality monitoring to include sediments, so as to protect human health and other aquatic lives. Copyright © 2015 Elsevier

  18. Spatial and Seasonal Variation of dissolved organic carbon (DOC) concentrations in Irish streams: importance of soil and topography characteristics.

    Science.gov (United States)

    Liu, Wen; Xu, Xianli; McGoff, Nicola M; Eaton, James M; Leahy, Paul; Foley, Nelius; Kiely, Gerard

    2014-05-01

    Dissolved organic carbon (DOC) concentrations have increased in many sites in Europe and North America in recent decades. High DOC concentrations can damage the structure and functions of aquatic ecosystems by influencing water chemistry. This study investigated the spatial and seasonal variation of DOC concentrations in Irish streams across 55 sites at seven time occasions over 1 year (2006/2007). The DOC concentrations ranged from 0.9 to 25.9 mg/L with a mean value of 6.8 and a median value of 5.7 mg/L and varied significantly over the course of the year. The DOC concentrations from late winter (February: 5.2 ± 3.0 mg/L across 55 sites) and early spring (April: 4.5 ± 3.5 mg/L) had significantly lower DOC concentrations than autumn (October: mean 8.3 ± 5.6 mg/L) and early winter (December: 8.3 ± 5.1 mg/L). The DOC production sources (e.g., litterfall) or the accumulation of DOC over dry periods might be the driving factor of seasonal change in Irish stream DOC concentrations. Analysis of data using stepwise multiple linear regression techniques identified the topographic index (TI, an indication of saturation-excess runoff potential) and soil conditions (organic carbon content and soil drainage characteristics) as key factors in controlling DOC spatial variation in different seasons. The TI and soil carbon content (e.g., soil organic carbon; peat occurrence) are positively related to DOC concentrations, while well-drained soils are negatively related to DOC concentrations. The knowledge of spatial and seasonal variation of DOC concentrations in streams and their drivers are essential for optimum riverine water resources management.

  19. Seasonal Variations in Sugar Contents and Microbial Community Behavior in a Ryegrass Soil

    Science.gov (United States)

    Medeiros, P. M.; Fernandes, M. F.; Dick, R. P.; Simoneit, B. R.

    2004-12-01

    Soil is a complex mixture of numerous inorganic and organic constituents that vary in size, shape, chemical constitution and reactivity, and hosts numerous organisms. Total sugars have been estimated to constitute 10% (average) of soil organic matter, occurring in living and decaying organisms, as well as in extracellular materials. The role of sugars in soils is attributed to their influence on soil structure, chemical processes, plant nutrition and microbial activity. The sources of sugars in soils are: a) plants (the primary source); b) animals (the minor source), and c) microorganisms (fungi, bacteria, algae), which decompose the primary plant and animal material, and synthesize the major part of soil carbohydrates. A particular soil sample provides a momentary glimpse into a dynamic system (continuous addition, degradation and synthesis) that might, except for seasonal variations, be in equilibrium. The purpose of this study is to identify and quantify the major sugars in a grass soil and characterize the relationship between their concentration variations and soil microbial behavior over an annual cycle. Soil samples were collected monthly in a ryegrass field close to Corvallis, Oregon, and analyzed by gas chromatography-mass spectrometry as total silylated extracts for sugar composition, and by gas chromatography-flame ionization as fatty acid methyl esters derived from phospholipids and neutral lipids (PLFA and NLFA, respectively). The preliminary results of the first six-month experiment (from January to June, 2004) show that as the ambient temperatures increase the sugar concentrations (glucose, fructose, sucrose and trehalose) also tend to increase in the soil. A decrease is observed in March when precipitation was low during the whole month. The same trend is observed for the active biomass of fungi and bacteria estimated by their fatty acids derived from phospholipids. Fatty acids 18:2ω 6c and 18:3ω 6c are used as fungal biomarkers. Branched (15:0i

  20. Comparison of seasonal variation in the fasting respiratory quotient of young Japanese, Polish and Thai women in relation to seasonal change in their percent body fat

    Directory of Open Access Journals (Sweden)

    Morinaka Tomoko

    2012-05-01

    Full Text Available Abstract Background From the viewpoint of human physiological adaptability, we previously investigated seasonal variation in the amount of unabsorbed dietary carbohydrates from the intestine after breakfast in Japanese, Polish and Thai participants. In this investigation we found that there were significant seasonal variations in the amount of unabsorbed dietary carbohydrates in Japanese and Polish participants, while we could not find significant seasonal variation in Thai participants. These facts prompted us to examine seasonal variations in the respiratory quotient after an overnight fast (an indicator of the ratio of carbohydrate and fat oxidized after the last meal with female university students living in Osaka (Japan, Poznan (Poland and Chiang Mai (Thailand. Methods We enrolled 30, 33 and 32 paid participants in Japan, Poland and Thailand, respectively, and measurements were taken over the course of one full year. Fasting respiratory quotient was measured with the participants in their postabsorptive state (after 12 hours or more fasting before respiratory quotient measurement. Respiratory quotient measurements were carried out by means of indirect calorimetry using the mixing chamber method. The percent body fat was measured using an electric bioelectrical impedance analysis scale. Food intake of the participants in Osaka and Poznan were carried out by the Food Frequency Questionnaire method. Results There were different seasonal variations in the fasting respiratory quotient values in the three different populations; with a significant seasonal variation in the fasting respiratory quotient values in Japanese participants, while those in Polish and Thai participants were non-significant. We found that there were significant seasonal changes in the percent body fat in the three populations but we could not find any significant correlation between the fasting respiratory quotient values and the percent body fat. Conclusions There were

  1. Seasonal variation of plankton communities influenced by environmental factors in an artificial lake

    Science.gov (United States)

    Li, Xuemei; Yu, Yuhe; Zhang, Tanglin; Feng, Weisong; Ao, Hongyi; Yan, Qingyun

    2012-05-01

    We evaluated the seasonal variation in plankton community composition in an artificial lake. We conducted microscopic analysis and denaturing gradient gel electrophoresis (DGGE) of PCR-amplified partial 16S rRNA and 18S rRNA genes to characterize the plankton community. The clustering of unweighted pair group method with arithmetic mean (UPGMA) was then used to investigate the similarity of these plankton communities. DGGE fingerprinting revealed that samples collected at the different sites within a season shared high similarity and were generally grouped together. In contrast, we did not observe any seasonal variation based on microscopic analysis. Redundancy analysis (RDA) of the plankton operational taxonomic units (OTUs) in relation to environmental factors revealed that transparency was negatively correlated with the first axis ( R=-0.931), and temperature and total phosphorus (TP) were positively correlated with the first axis ( R=0.736 and R=0.660, respectively). In conclusion, plankton communities in the artificial lake exhibited significant seasonal variation. Transparency, phosphorus and temperature appear to be the major factors driving the differences in plankton composition.

  2. Seasonal Variation in Essential oil Composition of Artemisianilagirica var. septentrionalis from Foot Hills of Western Himalaya

    Directory of Open Access Journals (Sweden)

    Rajendra Chandra Padalia

    2014-05-01

    Full Text Available Essential oils composition of the aerial parts of Artemisia nilagirica (Clarke Pamp. var. septentrionalis Pamp. in different seasons viz. spring, summer, rainy, autumn and winter seasons under foot hills agroclimatic conditions of western Himalaya were analyzed and compared by GC–FID and GC–MS. Essential oils were mainly composed of monoterpenoids (59.0%-77.3% and sesquiterpenoids (15.7%-31.6%. The major constituents identified were artemisia ketone (38.3%-61.2%, chrysanthenone (1.5%-7.7%, germacrene D (3.1%-6.8%, β-caryophyllene (1.9%-6.8%, germacra-4,5,10-trien-1-α-ol (1.9%-4.9% and artemisia alcohol (1.4%-3.6%. Compositional analysis showed significant variations in the terpenoid compositions due to seasonal variations. Further, this is for the first time the seasonal variations in essential oil compositions of artemisia ketone rich chemotype of A. nilagirica var. septentrionalis is being reported from India.

  3. Seasonal variation of the global mixed layer depth: comparison between Argo data and FIO-ESM

    Science.gov (United States)

    Zhang, Yutong; Xu, Haiming; Qiao, Fangli; Dong, Changming

    2018-03-01

    The present study evaluates a simulation of the global ocean mixed layer depth (MLD) using the First Institute of Oceanography-Earth System Model (FIOESM). The seasonal variation of the global MLD from the FIO-ESM simulation is compared to Argo observational data. The Argo data show that the global ocean MLD has a strong seasonal variation with a deep MLD in winter and a shallow MLD in summer, while the spring and fall seasons act as transitional periods. Overall, the FIO-ESM simulation accurately captures the seasonal variation in MLD in most areas. It exhibits a better performance during summer and fall than during winter and spring. The simulated MLD in the Southern Hemisphere is much closer to observations than that in the Northern Hemisphere. In general, the simulated MLD over the South Atlantic Ocean matches the observation best among the six areas. Additionally, the model slightly underestimates the MLD in parts of the North Atlantic Ocean, and slightly overestimates the MLD over the other ocean basins.

  4. Seasonal Variations of the Antioxidant Composition in Ground Bamboo Sasa argenteastriatus Leaves

    Directory of Open Access Journals (Sweden)

    Youzuo Zhang

    2012-02-01

    Full Text Available Sasa argenteastriatus, with abundant active compounds and high antioxidant activity in leaves, is a new leafy bamboo grove suitable for exploitation. To utilize it more effectively and scientifically, we investigate the seasonal variations of antioxidant composition in its leaves and antioxidant activity. The leaves of Sasa argenteastriatus were collected on the 5th day of each month in three same-sized sample plots from May 2009 to May 2011. The total flavonoids (TF: phenolics (TP and triterpenoid (TT of bamboo leaves were extracted and the contents analyzed by UV-spectrophotometer. Our data showed that all exhibited variations with the changing seasons, with the highest levels appearing in November to March. Antioxidant activity was measured using DPPH and FRAP methods. The highest antioxidant activity appeared in December with the lowest in May. Correlation analyses demonstrated that TP and TF exhibited high correlation with bamboo antioxidant activity. Eight bamboo characteristic compounds (orientin, isoorientin, vitexin, homovitexin and p-coumaric acid, chlorogenic acid, caffeic acid, ferulic acid were determined by RP-HPLC synchronously. We found that chlorogenic acid, isoorientin and vitexin are the main compounds in Sasa argenteastriatus leaves and the content of isovitexin and chlorogenic acid showed a similar seasonal variation with the TF, TP and TT. Our results suggested that the optimum season for harvesting Sasa argenteastriatus leaves is between autumn and winter.

  5. [Seasonal variations in estrus behavior and ovulatory activity in Chios and Serres ewes in Greece].

    Science.gov (United States)

    Avdi, M; Driancourt, M A; Chemineau, P

    1993-01-01

    Sheep are seasonal breeders, but a lower seasonality has been reported for sheep breeds from the Mediterranean countries enabling spring matings. To further substantiate this, the present study compared seasonal variation in oestrus behaviour and ovulation in two Greek breeds (Chios and Serres) maintained in the same environment. In 27 adult ewes of each breed, oestrus behaviour, the occurrence of ovulation and ovulation rate were monitored during 2 successive years by daily inspection by rams, weekly progesterone assay in circulating blood plasma and monthly ovarian laparoscopy. The periods of anoestrus (109 +/- 8 (wk) vs 178 +/- 5 d) and anovulation (63 +/- 8 vs 149 +/- 6 d) were significantly shorter (P duration of oestrus was also longer in Chios ewes (1.8 +/- 0.05 vs 1.5 +/- 0.06 d; P = 0.002). There were significant correlations between the duration of anovulatory periods of the 2 successive years in Chios (r = 0.43) but not Serres ewes. Ovulation rate was positively related to the onset of the sexual season in Serres but not in Chios ewes. The present data suggest that: i) the efficiency of Serres but not in Chios ewes. The present data suggest that: i) the efficiency of spring mating in these breeds is suboptimal since it is a period when the percentage of ewes exhibiting oestrus and ovulation as well as ovulation rate are limited, ii) owing to the large variation in seasonality within Chios ewes and to the good between year correlation in features of seasonality, selection against seasonality in Chios ewes could be worthwhile.

  6. Seasonal variations of aerosol residence time in the lower atmospheric boundary layer

    International Nuclear Information System (INIS)

    Ahmed, A.A.; Mohamed, A.; Ali, A.E.; Barakat, A.; Abd El-Hady, M.; El-Hussein, A.

    2004-01-01

    During a one year period, from Jan. 2002 up to Dec. 2002, approximately 130 air samples were analyzed to determine the atmospheric air activity concentrations of short- and long-lived ( 222 Rn) decay products 214 Pb and 210 Pb. The samples were taken by using a single-filter technique and γ-spectrometry was applied to determine the activity concentrations. A seasonal fluctuation in the concentration of 214 Pb and 210 Pb in surface air was observed. The activity concentrations of both radionuclides were observed to be relatively higher during the winter/autumn season than in spring/summer season. The mean activity concentration of 214 Pb and 210 Pb within the whole year was found to be 1.4±0.27 Bq m -3 and 1.2±0.15 mBq m -3 , respectively. Different 210 Pb: 214 Pb activity ratios during the year varied between 1.78x10 -4 and 1.6x10 -3 with a mean value of 8.9x10 -4 ±7.6x10 -5 . From the ratio between the activity concentrations of the radon decay products 214 Pb and 210 Pb a mean residence time (MRT) of aerosol particles in the atmosphere of about 10.5±0.91 d could be estimated. The seasonal variation pattern shows relatively higher values of MRT in spring/summer season than in winter/autumn season. The MRT data together with relative humidity (RH), air temperature (T) and wind speed (WS), were used for a comprehensive regression analysis of its seasonal variation in the atmospheric air

  7. Effects of seasonal and climate variations on calves' thermal comfort and behaviour.

    Science.gov (United States)

    Tripon, Iulian; Cziszter, Ludovic Toma; Bura, Marian; Sossidou, Evangelia N

    2014-09-01

    The aim of this study was to measure the effect of season and climate variations on thermal comfort and behaviour of 6-month-old dairy calves housed in a semi-opened shelter to develop animal-based indicators for assessing animal thermal comfort. The ultimate purpose was to further exploit the use of those indicators to prevent thermal stress by providing appropriate care to the animals. Measurements were taken for winter and summer seasons. Results showed that season significantly influenced (P ≤ 0.01) the lying down behaviour of calves by reducing the time spent lying, from 679.9 min in winter to 554.1 min in summer. Moreover, season had a significant influence (P ≤ 0.01) on feeding behaviour. In detail, the total length of feeding periods was shorter in winter, 442.1 min in comparison to 543.5 min in summer. Time spent drinking increased significantly (P ≤ 0.001), from 11.9 min in winter to 26.9 min in summer. Furthermore, season had a significant influence (P ≤ 0.001) on self grooming behaviour which was 5.5 times longer in duration in winter than in summer (1,336 s vs 244 s). It was concluded that calves' thermal comfort is affected by seasonal and climate variations and that this can be assessed by measuring behaviour with animal-based indicators, such as lying down, resting, standing up, feeding, rumination, drinking and self grooming. The indicators developed may be a useful tool to prevent animal thermal stress by providing appropriate housing and handling to calves under seasonal and climate challenge.

  8. What Controls Seasonal Variation of Phytoplankton Growth in the East China Sea?

    Science.gov (United States)

    Liu, K.; Chao, S.; Lee, H.; Gong, G.; Teng, Y.

    2009-05-01

    The seasonal variation of phytoplankton growth in the East China Sea (ECS) is simulated with a three- dimensional coupled physical-biogeochemical model, which includes discharges from Changjiang (aka the Yangtze River). The purpose is to determine the main control on the seasonality of primary productivity in the ECS shelf, which nurtures rich biological resources. The model has a horizontal resolution of 1/6 degree in the domain from 23N to 41N and from 116E to 134E, excluding the Japan/East Sea, and 33 layers in the vertical. The nitrogen-based biogeochemical model has four compartments: dissolved inorganic nitrogen (DIN), phytoplankton, zooplankton and detritus. The chlorophyll to phytoplankton ratio depends on light and DIN availability. The model is driven by monthly climatological winds with the sea surface temperature, salinity and DIN relaxed towards the climatological mean values. It successfully reproduces the observed seasonal variation of phytoplankton growth over the ECS shelf with a strong peak in later spring and summer. The modeled annual mean primary production over the entire ECS shelf is 439 mg C m-2 d-1, which falls within the reported range of 390-529 mg C m-2 d-1. It also reproduces the marked gradient of DIN across the shelf decreasing away from the Changjiang River plume. An alternative model run, Free-N, which deviates from the standard run by essentially removing nudging on DIN, generates the same seasonal pattern of primary productivity but somewhat reduced productivity. In yet another alternative run, Fix-PAR, which deviates from Free-N by removing the seasonal cycle of photosynthetically active radiation, the seasonality of primary productivity almost vanishes. These model results demonstrate that light availability is the major control on the seasonality of primary productivity. However, nutrient supply from vertical nutrient pumping and from Changjiang discharges is still important. It is the insufficient nutrient pumping that leads

  9. Seasonal variation of the flow in the strait of Bah al Mandab

    OpenAIRE

    Smeed, D

    1997-01-01

    There is a strong seasonal variation in the exchange flow through the strait of Bah al Mandab connecting the Red Sea to the Gulf of Aden (Thompson, 1939). In the winter a two-layer flow is observed in the strait. Dense intermediate water from the Red Sea flows into the Gulf of Aden and warmer fresher surface water flows into the Red Sea. In the summer season the direction of the surface flow is reversed and a third layer, of density between that of the surface layer and that of the intermedia...

  10. Seasonal variation in hormonal responses of timber rattlesnakes (Crotalus horridus) to reproductive and environmental stressors.

    Science.gov (United States)

    Lutterschmidt, William I; Lutterschmidt, Deborah I; Mason, Robert T; Reinert, Howard K

    2009-08-01

    Data addressing adrenocortical modulation across taxonomic groups are limited, especially with regard to how female reproductive condition influences the sensitivity of the hypothalamus-pituitary-adrenal axis. We investigated seasonal and reproductive variation in basal and stress-induced hormone profiles in a population of free-ranging timber rattlesnakes (Crotalus horridus) in north-central Pennsylvania during spring (i.e., May), summer (i.e., July), and early fall (i.e., September). Baseline corticosterone concentrations varied seasonally and were significantly lower during the summer sampling period in July. We observed a significant negative relationship between baseline corticosterone and testosterone in male snakes, while baseline corticosterone and estradiol tended to be positively correlated in females. Treatment of snakes with 1 h of capture stress significantly increased corticosterone across all seasons. However, there was a significant interaction between corticosterone responses to capture stress and season, suggesting that adrenocortical function is modulated seasonally. Because elevated corticosterone may be associated with reproduction, we asked whether hormonal stress responses vary with female reproductive condition. Although sample sizes are low, reproductive snakes had significantly higher baseline and stress-induced corticosterone concentrations than non-reproductive or post-parturient females. Further, despite similar baseline corticosterone concentrations between non-reproductive and post-parturient rattlesnakes, post-parturient females responded to capture stress with a significantly higher increase in corticosterone. Collectively, these data suggest that the sensitivity of the hypothalamus-pituitary-adrenal axis varies both seasonally and with changing reproductive states.

  11. Seasonal Variations in Physical Fitness and Performance Indices of Elite Soccer Players

    Directory of Open Access Journals (Sweden)

    Yoav Meckel

    2018-02-01

    Full Text Available The aim of the study was to investigate seasonal variations in fitness and performance indices of professional male soccer players. Eighteen professional male soccer players (age range 22–32 years completed three similar sets of tests at three stages of the season: before preseason; after preseason and the middle of the competitive in-season. A significant decrease in body mass and percent fat was found during the preseason. A significant improvement (p < 0.05 was found in the vertical jump (preseason: 37.0 ± 5.3, post-preseason: 39.0 ± 4.8, mid-season: 40.3 ± 5.5 cm, the 4 × 10-m agility test (preseason: 8.1 ± 0.2, post-preseason: 7.9 ± 0.2, mid-season: 8.1 ± 0.3 s, flexibility (preseason: 45.2 ± 8.8, post-preseason: 48.2 ± 7.0, mid-season: 49.9 ± 6.9 cm and aerobic capacity (preseason: 52.7 ± 6.6, post-preseason: 56.4 ± 6.0, mid-season: 57.4 ± 5.4 mL/kg/min during preseason, with no further change during mid-season. Repeated sprint test (RST (6 × 30-m performance indices showed significant deterioration (p < 0.05 in ideal sprint time (IS; preseason: 21.8 ± 1.0, post-preseason: 23.0 ± 0.8, mid-season: 23.2 ± 0.8 s and total sprint time (TS; preseason: 22.5 ± 0.7, post-preseason: 23.5 ± 0.6, mid-season: 23.8 ± 0.6 s during preseason, with no further changes during mid-season. However, performance decrement (PD significantly decreased during the preseason with no change during mid-season. The findings suggest that while power training was probably responsible for the anaerobic fitness improvement, the high-volume training led to improvement in aerobic fitness during the preseason. However, the low-intensity aerobic-type training, coupled with the high total training load, may have led to fatigue and decreases in IS and TS during the preseason.

  12. A study on seasonal variations of indoor gamma dose in Bangladesh

    International Nuclear Information System (INIS)

    Miah, M. Idrish

    2005-01-01

    Monthly variation of gamma dose rate measured in indoor air of buildings of Bangladesh was found to vary cosinusoidally through a period of 1 year. Significant seasonal variations were observed. Maximum dose rate, however, was observed in January and a minimum in July. Dose rate in January was 32% higher than the annual average, whereas dose rate in July was 50% lower. Seasonally varied ventilation and air exchange rates of the houses might play an important role in the observed variation. The average reduction with respect to winter dose was 59% in summer. Because of lower ventilation and air exchange rates between indoor and outdoor atmosphere, it is expected that the indoor dose rate would be higher in basements than that of upper floors. Monthly dose rate was also found to be influenced by the meteorological conditions. Correlations between dose rate and temperature (r 2 =0.85), rainfall (r=-0.83) and atmospheric pressure (r=0.92) were obtained, but no significant correlation (r=-0.45) was seen between dose rate and humidity. The results show that the seasonal variations of indoor dose rates should be taken into account to estimate annual effective dose equivalent. (author)

  13. Seasonal variation in kangaroo tooth enamel oxygen and carbon isotopes in southern Australia

    Science.gov (United States)

    Brookman, Tom H.; Ambrose, Stanley H.

    2012-09-01

    Serial sampling of tooth enamel growth increments for carbon and oxygen isotopic analyses of Macropus (kangaroo) teeth was performed to assess the potential for reconstructing paleoseasonality. The carbon isotope composition of tooth enamel apatite carbonate reflects the proportional intake of C3 and C4 vegetation. The oxygen isotopic composition of enamel reflects that of ingested and metabolic water. Tooth enamel forms sequentially from the tip of the crown to the base, so dietary and environmental changes during the tooth's formation can be detected. δ13C and δ18O values were determined for a series of enamel samples drilled from the 3rd and 4th molars of kangaroos that were collected along a 900 km north-south transect in southern Australia. The serial sampling method did not yield pronounced seasonal isotopic variation patterns in Macropus enamel. The full extent of dietary isotopic variation may be obscured by attenuation of the isotopic signal during enamel mineralisation. Brachydont (low-crowned) Macropus teeth may be less sensitive to seasonal variation in isotopic composition due to time-averaging during mineralisation. However, geographic variations observed suggest that there may be potential for tracking latitudinal shifts in vegetation zones and seasonal environmental patterns in response to climate change.

  14. Biomonitoring seasonal variation of urban air polycyclic aromatic hydrocarbons (PAHs) using Ficus benghalensis leaves

    International Nuclear Information System (INIS)

    Prajapati, Santosh Kumar; Tripathi, B.D.

    2008-01-01

    Temporal and seasonal variations of polycyclic aromatic hydrocarbons (PAHs) concentrations in leaves of Ficus benghalensis were investigated in Varanasi city (India). Leaf samples were collected from six sites from urban area of Varanasi and from a control site. PAH extraction was done by sonication in dichloromethane-acetone and quantification by GC-MS. In January total leaf PAHs concentrations at all the urban sites were twice higher as compared to other season's viz. summer and rainy. In contrast, at the control site leaf PAHs concentrations showed lower values than urban sites. The maximum concentrations of total PAHs in winter were due to the medium molecular weight PAHs which increases with respect to both low and high molecular weight PAHs. The temporal variation of medium molecular weight PAHs was similar both at the urban and remote sites. These results support biomonitoring ability of Ficus benghalensis leaves to temporal variations in PAHs contamination. - Biomonitoring PAHs in atmosphere using F. benghalensis leaves for its temporal and seasonal variation is cost effective as well as easier

  15. Seasonal variations in red deer (Cervus elaphus) hematology related to antler growth and biometrics measurements.

    Science.gov (United States)

    Gaspar-López, Enrique; Landete-Castillejos, Tomás; Estevez, Jose Antonio; Ceacero, Francisco; Gallego, Laureano; García, Andrés Jose

    2011-04-01

    The aim of the study was to relate seasonal hematology changes with the rest of physiological variations suffered by red deer, such as antler and biometrics cycle, and to assess the relationship between hematology and the effort performed in antler development. Blood samples were taken from 21 male red deer every 4 weeks during 18 months. Samples were analyzed for the main hematological parameters. Simultaneously, biometrics measurements were taken, such as antler length, body weight, body condition score, testicular diameter (TD), and thoracic and neck girth. All the blood cell types (erythrocytes, leukocytes, and platelets) showed seasonal variations, increasing as antler cleaning approached, as did hematocrit and hemoglobin. The final size of antlers was negatively related to leukocyte count, nonlymphoid leukocyte count, red cell distribution width, mean corpuscular hemoglobin, mean platelet volume, and TD, whereas it was positively related to body condition during antler growth. Huge seasonal variations in some hematological values have been found to be related to changes in antler and biometrics measurements. Since these variations are even greater than the caused by deer handling, they should be taken into account when evaluating hematology in deer populations. Copyright © 2011 Wiley-Liss, Inc., A Wiley Company.

  16. Evaluation of seasonal variation of water quality using multivariate statistical analysis and irrigation parameter indices in Ajakanga area, Ibadan, Nigeria

    Science.gov (United States)

    Ganiyu, S. A.; Badmus, B. S.; Olurin, O. T.; Ojekunle, Z. O.

    2018-03-01

    The variation of groundwater quality across different regions is of great importance in the study of groundwater so as to ascertain the sources of contaminants to available water sources. Geochemical assessment of groundwater samples from hand-dug wells were done within the vicinity of Ajakanga dumpsite, Ibadan, Southwestern, Nigeria, with the aim of assessing their suitability for domestic and irrigation purposes. Ten groundwater samples were collected both in dry and wet seasons for analysis of physicochemical parameters such as: pH, EC, TDS, Na+, K+, Ca2+, Mg2+, HCO3^{ - } Cl-, SO4^{2 - }, NO3^{2 - } principal component analysis (PCA) and cluster analysis (CA) were used to determine probable sources of groundwater contamination. The results of the analyses showed the groundwater samples to be within permissible limits of WHO/NSDWQ, while elevated values of concentrations of most analyzed chemical constituents in water samples were noticed in S1 and S10 due to their nearness to the dumpsite and agricultural overflow, respectively. Groundwater in the study area is of hard, fresh and alkaline nature. There are very strong associations between EC and TDS, HCO3^{ - } and CO3^{2 - } in both seasons. PCA identified five and three major factors accounting for 95.7 and 88.7% of total variation in water quality for dry and wet seasons, respectively. PCA also identified factors influencing water quality as those probably related to mineral dissolution, groundwater-rock interaction, weathering process and anthropogenic activities from the dumpsite. Results of CA show groups based on similar water quality characteristics and on the extent of proximity to the dumpsite. Assessment for irrigation purpose showed that most of the water samples were suitable for agricultural purpose except in a few locations.

  17. Seasonal variation of ozone deposition to a tropical rain forest in southwest Amazonia

    Directory of Open Access Journals (Sweden)

    U. Rummel

    2007-10-01

    Full Text Available Within the project EUropean Studies on Trace gases and Atmospheric CHemistry as a contribution to Large-scale Biosphere-atmosphere experiment in Amazonia (LBA-EUSTACH, we performed tower-based eddy covariance measurements of O3 flux above an Amazonian primary rain forest at the end of the wet and dry season. Ozone deposition revealed distinct seasonal differences in the magnitude and diel variation. In the wet season, the rain forest was an effective O3 sink with a mean daytime (midday maximum deposition velocity of 2.3 cm s−1, and a corresponding O3 flux of −11 nmol m−2 s−1. At the end of the dry season, the ozone mixing ratio was about four times higher (up to maximum values of 80 ppb than in the wet season, as a consequence of strong regional biomass burning activity. However, the typical maximum daytime deposition flux was very similar to the wet season. This results from a strong limitation of daytime O3 deposition due to reduced plant stomatal aperture as a response to large values of the specific humidity deficit. As a result, the average midday deposition velocity in the dry burning season was only 0.5 cm s−1. The large diel ozone variation caused large canopy storage effects that masked the true diel variation of ozone deposition mechanisms in the measured eddy covariance flux, and for which corrections had to be made. In general, stomatal aperture was sufficient to explain the largest part of daytime ozone deposition. However, during nighttime, chemical reaction with nitrogen monoxide (NO was found to contribute substantially to the O3 sink in the rain forest canopy. Further contributions were from non-stomatal plant uptake and other processes that could not be clearly identified.

    Measurements, made simultaneously on a 22 years old cattle pasture enabled the spatially and temporally direct comparison of O3

  18. Seasonal variation in accumulation of persistent organic pollutants in an Arctic marine benthic food web

    Energy Technology Data Exchange (ETDEWEB)

    Evenset, A., E-mail: anita.evenset@akvaplan.niva.no [Akvaplan-niva. Fram Centre, Tromsø (Norway); University of Tromsø, The Arctic University of Norway, Tromsø (Norway); Hallanger, I.G. [University of Tromsø, The Arctic University of Norway, Tromsø (Norway); Tessmann, M. [Akvaplan-niva. Fram Centre, Tromsø (Norway); Institute for Hydrobiology and Fisheries Research, University of Hamburg (Germany); Warner, N. [Norwegian Institute for Air Research, Fram Centre, Tromsø (Norway); Ruus, A. [Norwegian Institute for Water Research, Oslo (Norway); Borgå, K. [Norwegian Institute for Water Research, Oslo (Norway); Department of Biosciences, P.O. Box 1066, Blindern 0316, Oslo (Norway); Gabrielsen, G.W. [Norwegian Polar Institute, Fram Centre, Tromsø (Norway); Christensen, G. [Akvaplan-niva. Fram Centre, Tromsø (Norway); Renaud, P.E. [Akvaplan-niva. Fram Centre, Tromsø (Norway); University Centre in Svalbard, Longyearbyen (Norway)

    2016-01-15

    The aim of the present study was to investigate seasonal variation in persistent organic pollutant (POP) concentrations, as well as food-web biomagnification, in an Arctic, benthic marine community. Macrozoobenthos, demersal fish and common eiders were collected both inside and outside of Kongsfjorden, Svalbard, during May, July and October 2007. The samples were analysed for a selection of legacy chlorinated POPs. Overall, low levels of POPs were measured in all samples. Although POP levels and accumulation patterns showed some seasonal variation, the magnitude and direction of change was not consistent among species. Overall, seasonality in bioaccumulation in benthic biota was less pronounced than in the pelagic system in Kongsfjorden. In addition, the results indicate that δ{sup 15}N is not a good predictor for POP-levels in benthic food chains. Other factors, such as feeding strategy (omnivory, necrophagy versus herbivory), degree of contact with the sediment, and a high dependence on particulate organic matter (POM), with low POP-levels and high δ{sup 15}N-values (due to bacterial isotope enrichment), seem to govern the uptake of the different POPs and result in loads deviating from what would be expected consulting the trophic position alone. - Highlights: • Seasonal variation in POP biomagnification was investigated in a benthic food web. • Levels of POPs are generally low in benthic species from Kongsfjorden, Svalbard. • POP-concentrations varied with season, but direction of change varied among taxa. • No POP-biomagnification, except for cis-nonachlor, was detected in this study. • δ{sup 15}N-values does not seem to be a good proxy for trophic level in macrozoobenthos.

  19. Seasonal variation in accumulation of persistent organic pollutants in an Arctic marine benthic food web

    International Nuclear Information System (INIS)

    Evenset, A.; Hallanger, I.G.; Tessmann, M.; Warner, N.; Ruus, A.; Borgå, K.; Gabrielsen, G.W.; Christensen, G.; Renaud, P.E.

    2016-01-01

    The aim of the present study was to investigate seasonal variation in persistent organic pollutant (POP) concentrations, as well as food-web biomagnification, in an Arctic, benthic marine community. Macrozoobenthos, demersal fish and common eiders were collected both inside and outside of Kongsfjorden, Svalbard, during May, July and October 2007. The samples were analysed for a selection of legacy chlorinated POPs. Overall, low levels of POPs were measured in all samples. Although POP levels and accumulation patterns showed some seasonal variation, the magnitude and direction of change was not consistent among species. Overall, seasonality in bioaccumulation in benthic biota was less pronounced than in the pelagic system in Kongsfjorden. In addition, the results indicate that δ"1"5N is not a good predictor for POP-levels in benthic food chains. Other factors, such as feeding strategy (omnivory, necrophagy versus herbivory), degree of contact with the sediment, and a high dependence on particulate organic matter (POM), with low POP-levels and high δ"1"5N-values (due to bacterial isotope enrichment), seem to govern the uptake of the different POPs and result in loads deviating from what would be expected consulting the trophic position alone. - Highlights: • Seasonal variation in POP biomagnification was investigated in a benthic food web. • Levels of POPs are generally low in benthic species from Kongsfjorden, Svalbard. • POP-concentrations varied with season, but direction of change varied among taxa. • No POP-biomagnification, except for cis-nonachlor, was detected in this study. • δ"1"5N-values does not seem to be a good proxy for trophic level in macrozoobenthos.

  20. Seasonal variation in hemodialysis initiation: A single-center retrospective analysis.

    Directory of Open Access Journals (Sweden)

    Yujiro Maeoka

    Full Text Available The number of new dialysis patients has been increasing worldwide, particularly among elderly individuals. However, information on seasonal variation in hemodialysis initiation in recent decades is lacking, and the seasonal distribution of patients' conditions immediately prior to starting dialysis remains unclear. Having this information could help in developing a modifiable approach to improving pre-dialysis care. We retrospectively investigated the records of 297 patients who initiated hemodialysis at Hiroshima Prefectural Hospital from January 1st, 2009 to December 31st, 2013. Seasonal differences were assessed by χ2 or Kruskal-Wallis tests. Multiple comparison analysis was performed with the Steel test. The overall number of patients starting dialysis was greatest in winter (n = 85, 28.6%, followed by spring (n = 74, 24.9%, summer (n = 70, 23.6%, and autumn (n = 68, 22.9%, though the differences were not significant. However, there was a significant winter peak in dialysis initiation among patients aged ≥65 years, but not in those aged <65 years. Fluid overload assessed by clinicians was the most common uremic symptom among all patients, but a winter peak was only detected in patients aged ≥65 years. The body weight gain ratio showed a similar trend to fluid overload assessed by clinicians. Pulmonary edema was most pronounced in winter among patients aged ≥65 years compared with other seasons. The incidences of infection were modestly increased in summer and winter, but not statistically significant. Cardiac complications were similar in all seasons. This study demonstrated the existence of seasonal variation in dialysis initiation, with a winter peak among patients aged ≥65 years. The winter increment in dialysis initiation was mainly attributable to increased fluid overload. These findings suggest that elderly individuals should be monitored particularly closely during the winter.

  1. Seasonal variation in standardized litter decomposition and effects of elevation and land use at Mount Kilimanjaro

    Science.gov (United States)

    Becker, Joscha; Kuzyakov, Yakov

    2017-04-01

    Decomposition is one of most important ecological steps in organic matter and nutrient cycles, but studies and reliable data from tropical regions in Africa are still scarce. At the global scale, litter decomposition and recycling is controlled by climatic factors and land-use intensity. These factors can be linked to specific ecosystem characteristics along the unique elevation gradient of Mt. Kilimanjaro. Our objectives were to assess the effects of climatic conditions (i.e. elevation) and land-use intensity on C turnover and stabilization and investigated the seasonal variations. Tea-bag Index (see www.teatime4science.org) was used to measure decomposition of a standardized litter substrate by microorganisms and mesofauna coffee plantations or cloud forest (S=0.11) respectively and strongly increased again to a maximum of S=0.41 in the alpine helichrysum ecosystem. During all seasons, we found the highest decomposition rates at mid elevation. However, during both warm seasons the peak is shifted upslope. Savanna experienced the strongest seasonal variation, with 23 times higher S-values in dry- compared to rainy season. Mean annual k-values increased for about 30% with increasing land-use intensity. C stabilization in Mt. Kilimanjaro ecosystems is strongly dependent on seasonal moisture limitation (lower slope) and perennial temperature limitation (alpine zone). Ecosystems at mid elevation (around 1920 & 2120m) represent the interception zone of optimal moisture and temperature conditions. High input and fast turnover drive the C sequestration in these ecosystems, while restrains on decomposition control the C turnover in lower and higher elevation zones. Land-use intensification decreases stabilization from new C inputs in transition zones from savanna to maize monocultures and from traditional homegardens to large-scale coffee plantations.

  2. Seasonal variation in the mating system of a selfing annual with large floral displays.

    Science.gov (United States)

    Yin, Ge; Barrett, Spencer C H; Luo, Yi-Bo; Bai, Wei-Ning

    2016-03-01

    Flowering plants display considerable variation in mating system, specifically the relative frequency of cross- and self-fertilization. The majority of estimates of outcrossing rate do not account for temporal variation, particularly during the flowering season. Here, we investigated seasonal variation in mating and fertility in Incarvillea sinensis (Bignoniaceae), an annual with showy, insect-pollinated, 'one-day' flowers capable of delayed selfing. We examined the influence of several biotic and abiotic environmental factors on day-to-day variation in fruit set, seed set and patterns of mating. We recorded daily flower number and pollinator abundance in nine 3 × 3-m patches in a population at Mu Us Sand land, Inner Mongolia, China. From marked flowers we collected data on daily fruit and seed set and estimated outcrossing rate and biparental inbreeding using six microsatellite loci and 172 open-pollinated families throughout the flowering period. Flower density increased significantly over most of the 50-d flowering season, but was associated with a decline in levels of pollinator service by bees, particularly on windy days. Fruit and seed set declined over time, especially during the latter third of the flowering period. Multilocus estimates of outcrossing rate were obtained using two methods (the programs MLTR and BORICE) and both indicated high selfing rates of ∼80 %. There was evidence for a significant increase in levels of selfing as the flowering season progressed and pollinator visitation declined. Biparental inbreeding also declined significantly as the flowering season progressed. Temporal variation in outcrossing rates may be a common feature of the mating biology of annual, insect-pollinated plants of harsh environments but our study is the first to examine seasonal mating-system dynamics in this context. Despite having large flowers and showy floral displays, I. sinensis attracted relatively few pollinators. Delayed selfing by corolla dragging

  3. Seasonal variations of radon concentrations in single-family houses with different sub-structures

    DEFF Research Database (Denmark)

    Majborn, B.

    1992-01-01

    Seasonal variations of indoor radon concentrations have been studied in 70 single-family houses selected according to the type of sub-structure and the type of soil underneath the house. Five categories of sub-structure were included - slab-on-grade, crawl space, basement, and combinations...... of basement with slab-on-grade or crawl space. Half of the houses are located on clayey till and the other half on glaciofluvial gravel. In each house radon was measured in a living room and a bedroom, in the basement if present, and in the crawl space if present and accessible. The measurements were made...... with track detectors on a quarterly basis throughout a year. For living rooms and bedrooms the seasonal variations range from being highly significant for the slab-on-grade houses to being insignificant for the crawl space houses. For basements and crawl spaces the geometric mean radon concentrations do...

  4. Seasonal variation and solar activity dependence of the quiet-time ionospheric trough

    Science.gov (United States)

    Ishida, T.; Ogawa, Y.; Kadokura, A.; Hiraki, Y.; Häggström, I.

    2014-08-01

    We have conducted a statistical analysis of the ionospheric F region trough, focusing on its seasonal variation and solar activity dependence under geomagnetically quiet and moderate conditions, using plasma parameter data obtained via Common Program 3 observations performed by the European Incoherent Scatter (EISCAT) radar between 1982 and 2011. We have confirmed that there is a major difference in frictional heating between the high- and low-latitude sides of the EISCAT field of view (FOV) at ~73°0'N-60°5'N (geomagnetic latitude) at an altitude of 325 km, which is associated with trough formation. Our statistical results show that the high-latitude and midlatitude troughs occur on the high- and low-latitude sides of the FOV, respectively. Seasonal variations indicate that dissociative recombination accompanied by frictional heating is a main cause of trough formation in sunlit regions. During summer, therefore, the occurrence rate is maintained at 80-90% in the postmidnight high-latitude region owing to frictional heating by eastward return flow. Solar activity dependence on trough formation indicates that field-aligned currents modulate the occurrence rate of the trough during the winter and equinox seasons. In addition, the trough becomes deeper via dissociative recombination caused by an increased ion temperature with F10.7, at least in the equinox and summer seasons but not in winter.

  5. Daily and seasonal variations of outdoor alpha-activity concentration in Salzburg city/Austria

    International Nuclear Information System (INIS)

    Lettner, H.; Hubmer, A.K.; Rolle, R.; Winkler, R.; Steinhaeusler, F.

    1996-01-01

    Long-term continuous measurements of the atmospheric outdoor alpha-activity concentration have been performed by using a radioaerosol-monitor, roof-mounted 20 m above ground. The alpha-activity concentration was identified to be predominantly attributed to radon progeny. The total alpha-activity covers a range of two orders of magnitude. Three different components of variations could be identified with regard to temporal variations: Short-term diurnal component (daily variation), mid-term component (days to weeks) and long-term component (seasonal variation). Continuous measurements have been recorded since the end of 1993. The results of continuous measurements of the outdoor alpha-activity concentration over a time span from January 1994 to June 1995 are presented. (author)

  6. Seasonal variations of stable isotope in precipitation and moisture transport at Yushu,eastern Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Precipitation δ 18O at Yushu, eastern Tibetan Plateau, shows strong fluctuation and lack of clear seasonality. The seasonal pattern of precipitation stable isotope at Yushu is apparently different from either that of the southwest monsoon region to the south or that of the inland region to the north. This different seasonal pattern probably reflects the shift of different moisture sources. In this paper, we present the spatial comparison of the seasonal patterns of precipitation δ 18O, and calculate the moisture transport flux by using the NCAR/NCEP reanalysis data. This allows us to discuss the relation between moisture transport flux and precipitation δ 18O. This study shows that both the southwest monsoon from south and inland air mass transport from north affected the seasonal precipitation δ 18O at Yushu, eastern Tibetan Plateau. Southwest monsoon brings the main part of the moisture, but southwest transport flux is weaker than in the southern part of the Tibetan Plateau. However, contribution of the inland moisture from north or local evaporation moisture is enhanced. The combined effect is the strong fluctuation of summer precipitation δ 18O at Yushu and comparatively poor seasonality.

  7. Possible daily and seasonal variations in quantum interference induced by Chern-Simons gravity.

    Science.gov (United States)

    Okawara, Hiroki; Yamada, Kei; Asada, Hideki

    2012-12-07

    Possible effects of Chern-Simons (CS) gravity on a quantum interferometer turn out to be dependent on the latitude and direction of the interferometer on Earth in orbital motion around the Sun. Daily and seasonal variations in phase shifts are predicted with an estimate of the size of the effects, wherefore neutron interferometry with ~5 m arm length and ~10(-4) phase measurement accuracy would place a bound on a CS parameter comparable to the Gravity Probe B satellite.

  8. Seasonal and diurnal variations in potential alpha energy concentrations at a location in tropical Australia

    International Nuclear Information System (INIS)

    Quintarelli, F.; Akber, R.

    1998-01-01

    Full text: Atmospheric concentrations of radon progeny activity were measured at two locations in tropical Australia during the time period 1992 - 1994. Meteorological parameters including atmospheric pressure, temperature and humidity were also recorded. The data were analysed for seasonal and diurnal variations, in order to establish correlations and associations amongst radon progeny concentrations and meteorological parameters. The paper describes the findings, including the attachment behaviour of radon progeny to ambient aerosol

  9. Melanopsin Gene Variations Interact With Season to Predict Sleep Onset and Chronotype

    OpenAIRE

    Roecklein, Kathryn A.; Wong, Patricia M.; Franzen, Peter L.; Hasler, Brant P.; Wood-Vasey, W. Michael; Nimgaonkar, Vishwajit L.; Miller, Megan A.; Kepreos, Kyle M.; Ferrell, Robert E.; Manuck, Stephen B.

    2012-01-01

    The human melanopsin gene has been reported to mediate risk for seasonal affective disorder (SAD), which is hypothesized to be caused by decreased photic input during winter when light levels fall below threshold, resulting in differences in circadian phase and/or sleep. However, it is unclear if melanopsin increases risk of SAD by causing differences in sleep or circadian phase, or if those differences are symptoms of the mood disorder. To determine if melanopsin sequence variations are asso...

  10. Seasonal variation of technetium-99 in Fucus vesiculosus and its application as an oceanographic tracer

    DEFF Research Database (Denmark)

    Shi, Keliang; Hou, Xiaolin; Roos, Per

    2013-01-01

    The concentration of 99Tc was determined in archived time series seaweed samples collected at Klint (Denmark). The results demonstrate a significantly seasonal variation of 99Tc concentrations in Fucus vesiculosus with maximum values in winter and minimum values in summer. The mechanism driving t...... of (1.9 0.5) 105 L/kg, were obtained. This indicates that F. vesiculosus can be used as a reliable bioindicator to monitor 99Tc concentration in seawater....

  11. Global and regional seasonal variations of the geoid detected by GRACE

    Czech Academy of Sciences Publication Activity Database

    Kostelecký, J.; Bezděk, Aleš; Klokočník, Jaroslav

    2013-01-01

    Roč. 10, č. 3 (2013), s. 285-291 ISSN 1214-9705 R&D Projects: GA ČR GA13-36843S Grant - others:EU(XE) NTIS CZ1.05/1.1.00/02.0090 Institutional support: RVO:67985815 Keywords : GRACE mission * seasonal variations * geoid Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.667, year: 2013

  12. Anthropometric measurements of adolescents from two Amazonian ecosystems: variations according to seasonality.

    Science.gov (United States)

    Silva, Hilton P; Veiga, Gloria V; Kac, Gilberto; Pereira, Rosangela A

    2010-03-01

    This paper aims to describe the nutritional status of Caboclo adolescents living in two areas of the Amazon Basin. Two cross-sectional studies, the first in the dry and the second in the wet season, were carried out in two Amazonian ecosystems: the forest and black water ecosystem, and the floodplain and white water ecosystem. Measurements of weight, stature, arm circumference and triceps, subscapular and suprailiac skinfolds were performed on 247 adolescents (10-19 years of age). Nutritional status was classified using body mass index according to international criteria and the prevalence of underweight and overweight was estimated. Linear mixed effects models were used with the anthropometric measurements as dependent variables and time interval, place of residence, sex, age and stature variation as independent variables. During the wet season, the prevalence of overweight among girls was higher in the forest (42%) than in the floodplain (9%). Longitudinal linear regression models showed that the arm circumference measurement was influenced both by seasonality and location, revealing that the increment between dry and wet seasons was less pronounced in the floodplain. At the time of the study, overweight already constituted a major public health concern among girls living in the forest area. In order to develop adequate public health policies for this important segment of the Amazon population further studies are necessary to investigate the role of environment and seasonality on the growth and nutritional status of adolescents.

  13. Seasonal variation in physical activity, sedentary behaviour and sleep in a sample of UK adults.

    Science.gov (United States)

    O'Connell, Sophie E; Griffiths, Paula L; Clemes, Stacy A

    2014-01-01

    Physical activity (PA), sedentary behaviour (SB), sleep and diet have all been associated with increased risk for chronic disease. Seasonality is often overlooked as a determinant of these behaviours in adults. Currently, no study has simultaneously monitored these behaviours in UK adults to assess seasonal variation. The present study investigated whether PA, SB, sleep and diet differed over season in UK adults. Forty-six adults (72% female; age = 41.7 ± 14.4 years, BMI = 24.9 ± 4.4 kg/m(2)) completed four 7-day monitoring periods; one during each season of the year. The ActiGraph GT1M was used to monitor PA and SB. Daily sleep diaries monitored time spent in bed (TIB) and total sleep time (TST). The European Prospective Investigation of Cancer (EPIC) food frequency questionnaire (FFQ) assessed diet. Repeated measures ANOVAs were used to identify seasonal differences in behaviours. Light-intensity PA was significantly higher in summer and spring (p diet (p > 0.05). Findings support the concept that health promotion campaigns need to encourage year-round participation in light intensity PA, whilst limiting SB, particularly during the winter months.

  14. A vegetation control on seasonal variations in global atmospheric mercury concentrations

    Science.gov (United States)

    Jiskra, Martin; Sonke, Jeroen E.; Obrist, Daniel; Bieser, Johannes; Ebinghaus, Ralf; Myhre, Cathrine Lund; Pfaffhuber, Katrine Aspmo; Wängberg, Ingvar; Kyllönen, Katriina; Worthy, Doug; Martin, Lynwill G.; Labuschagne, Casper; Mkololo, Thumeka; Ramonet, Michel; Magand, Olivier; Dommergue, Aurélien

    2018-04-01

    Anthropogenic mercury emissions are transported through the atmosphere as gaseous elemental mercury (Hg(0)) before they are deposited to Earth's surface. Strong seasonality in atmospheric Hg(0) concentrations in the Northern Hemisphere has been explained by two factors: anthropogenic Hg(0) emissions are thought to peak in winter due to higher energy consumption, and atmospheric oxidation rates of Hg(0) are faster in summer. Oxidation-driven Hg(0) seasonality should be equally pronounced in the Southern Hemisphere, which is inconsistent with observations of constant year-round Hg(0) levels. Here, we assess the role of Hg(0) uptake by vegetation as an alternative mechanism for driving Hg(0) seasonality. We find that at terrestrial sites in the Northern Hemisphere, Hg(0) co-varies with CO2, which is known to exhibit a minimum in summer when CO2 is assimilated by vegetation. The amplitude of seasonal oscillations in the atmospheric Hg(0) concentration increases with latitude and is larger at inland terrestrial sites than coastal sites. Using satellite data, we find that the photosynthetic activity of vegetation correlates with Hg(0) levels at individual sites and across continents. We suggest that terrestrial vegetation acts as a global Hg(0) pump, which can contribute to seasonal variations of atmospheric Hg(0), and that decreasing Hg(0) levels in the Northern Hemisphere over the past 20 years can be partly attributed to increased terrestrial net primary production.

  15. Seasonal variation in Hibiscus sabdariffa (Roselle) calyx phytochemical profile, soluble solids and α-glucosidase inhibition.

    Science.gov (United States)

    Ifie, Idolo; Ifie, Beatrice E; Ibitoye, Dorcas O; Marshall, Lisa J; Williamson, Gary

    2018-09-30

    Seasonal variations in crops can alter the profile and amount of constituent compounds and consequentially any biological activity. Differences in phytochemical profile, total phenolic content and inhibitory activity on α-glucosidase (maltase) of Hibiscus sabdariffa calyces grown in South Western Nigeria were determined over wet and dry seasons. The phenolic profile, organic acids and sugars were analysed using HPLC, while inhibition of rat intestinal maltase was measured enzymically. There was a significant increase (1.4-fold; p ≤ 0.05) in total anthocyanin content in the dry compared to wet planting seasons, and maltase inhibition from the dry season was slightly more potent (1.15-fold, p ≤ 0.05). Fructose (1.8-fold), glucose (1.8-fold) and malic acid (3.7-fold) were significantly higher (p ≤ 0.05) but citric acid was lower (62-fold, p ≤ 0.008) in the dry season. Environmental conditions provoke metabolic responses in Hibiscus sabdariffa affecting constituent phytochemicals and nutritional value. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. The specificity of host-bat fly interaction networks across vegetation and seasonal variation.

    Science.gov (United States)

    Zarazúa-Carbajal, Mariana; Saldaña-Vázquez, Romeo A; Sandoval-Ruiz, César A; Stoner, Kathryn E; Benitez-Malvido, Julieta

    2016-10-01

    Vegetation type and seasonality promote changes in the species composition and abundance of parasite hosts. However, it is poorly known how these variables affect host-parasite interaction networks. This information is important to understand the dynamics of parasite-host relationships according to biotic and abiotic changes. We compared the specialization of host-bat fly interaction networks, as well as bat fly and host species composition between upland dry forest and riparian forest and between dry and rainy seasons in a tropical dry forest in Jalisco, Mexico. Bat flies were surveyed by direct collection from bats. Our results showed that host-bat fly interaction networks were more specialized in upland dry forest compared to riparian forest. Bat fly species composition was different between the dry and rainy seasons, while host species composition was different between upland dry forest and riparian forest. The higher specialization in upland dry forest could be related to the differences in bat host species composition and their respective roosting habits. Variation in the composition of bat fly species between dry and rainy seasons coincides with the seasonal shifts in their species richness. Our study confirms the high specialization of host-bat fly interactions and shows the importance of biotic and abiotic factors to understand the dynamics of parasite-host interactions.

  17. Hybrid model for forecasting time series with trend, seasonal and salendar variation patterns

    Science.gov (United States)

    Suhartono; Rahayu, S. P.; Prastyo, D. D.; Wijayanti, D. G. P.; Juliyanto

    2017-09-01

    Most of the monthly time series data in economics and business in Indonesia and other Moslem countries not only contain trend and seasonal, but also affected by two types of calendar variation effects, i.e. the effect of the number of working days or trading and holiday effects. The purpose of this research is to develop a hybrid model or a combination of several forecasting models to predict time series that contain trend, seasonal and calendar variation patterns. This hybrid model is a combination of classical models (namely time series regression and ARIMA model) and/or modern methods (artificial intelligence method, i.e. Artificial Neural Networks). A simulation study was used to show that the proposed procedure for building the hybrid model could work well for forecasting time series with trend, seasonal and calendar variation patterns. Furthermore, the proposed hybrid model is applied for forecasting real data, i.e. monthly data about inflow and outflow of currency at Bank Indonesia. The results show that the hybrid model tend to provide more accurate forecasts than individual forecasting models. Moreover, this result is also in line with the third results of the M3 competition, i.e. the hybrid model on average provides a more accurate forecast than the individual model.

  18. Seasonal variation in the growth responses of some chlorophytic algal flora of the Red Sea

    Directory of Open Access Journals (Sweden)

    Abid Ali Ansari

    2017-06-01

    Full Text Available Seasonal variation in growth responses and antioxidant activities of four chlorophytic algal species, namely Ulva lactuca, Enteromorpha flexuoca, Cladophora prolifera, Chaetomorpha linum was investigated. Seasonal variation in the physico-chemical characteristics of water at the study site of the Red Sea was also determined. A significant variation was observed in water quality parameters in different seasons. All the algal species show higher accumulation of photosynthetic and accessory pigments in July and October and a significant decrease in January. Higher NPK content in all the four algal species was recorded in July, however, the contents were low in other months. Total protein contents were higher in July and October. Total carbohydrates in U. lactuca and E. flexuoca were significantly higher in July but in the other two species, C. prolifera and C. linum, maximum accumulation was observed in October. Antioxidant activities in all the species were most significant in January as compared to the other months. All the chlorphytic algae show prominent growth responses and antioxidant activities and are better adapted to changing climatic conditions. Due to their prompt responses even to minor changes in aquatic environment, they can be used as ecological indicators in coastal marine ecosystems.

  19. Seasonal variation in the composition and concentration of butyltin compounds in marine fish of Taiwan

    Energy Technology Data Exchange (ETDEWEB)

    Dong, C.D.; Chen, C.W.; Liu, L.L

    2004-10-01

    For the first time, strong evidence is presented to demonstrate that the accumulations of butyltin compounds (BTs) exhibit seasonal variations with respect to their compositions and concentrations in marine fishes. Measurements were made on the benthic ponyfish Leiogenathus splendens and lizardfish Trachinocephalus myops inhabiting the west coast of Taiwan. In the whole body samples of the ponyfish, BT concentrations ranged from 236 to 2501 ng/g wet wt, with those in winter considerably higher than in the other seasons (p<0.05). In a similar vein, proportions of mono- (MBT), di- (DBT) and tributyltin (TBT) differed significantly (p<0.001) depending upon the season, with TBT (75 and 50%) dominant in winter and spring and DBT (37 and 57%) and MBT (42 and 24%) dominant in summer and autumn, respectively. In the lizardfish, the concentrations of BTs were one to two orders of magnitude higher in the liver than in the muscle, i.e. 3058-11,473 vs. 36-159 ng/g wet wt, respectively. Concentrations of MBT, DBT and TBT in the muscle ranged, respectively, from 5 to 14, 8 to 35 and 23 to 110 ng/g wet wt, with the major compound being TBT (57-69%) in all seasons. However, in the liver, DBT concentrations, ranging from 992 to 7797 ng/g wet wt, differed seasonally with a descending order of autumn > summer > spring (p<0.05). Meanwhile, TBT (41%) was predominant in spring, whereas DBT (50 and 68%) was most heavily concentrated in summer and autumn (p<0.001). Seasonally mediated physiological changes, such as dilution due to growth and metabolic compensation, may play important roles in forming different BT accumulation patterns among seasons and organisms.

  20. Seasonal variation in the behaviour of a short-lived rodent.

    Science.gov (United States)

    Eccard, Jana A; Herde, Antje

    2013-11-15

    Short lived, iteroparous animals in seasonal environments experience variable social and environmental conditions over their lifetime. Animals can be divided into those with a "young-of-the-year" life history (YY, reproducing and dying in the summer of birth) and an "overwinter" life history (OW, overwintering in a subadult state before reproducing next spring).We investigated how behavioural patterns across the population were affected by season and sex, and whether variation in behaviour reflects the variation in life history patterns of each season. Applications of pace-of-life (POL) theory would suggest that long-lived OW animals are shyer in order to increase survival, and YY are bolder in order to increase reproduction. Therefore, we expected that in winter and spring samples, when only OW can be sampled, the animals should be shyer than in summer and autumn, when both OW and YY animals can be sampled.We studied common vole (Microtus arvalis) populations, which express typical, intra-annual density fluctuation. We captured a total of 492 voles at different months over 3 years and examined boldness and activity level with two standardised behavioural experiments. Behavioural variables of the two tests were correlated with each other. Boldness, measured as short latencies in both tests, was extremely high in spring compared to other seasons. Activity level was highest in spring and summer, and higher in males than in females. Being bold in laboratory tests may translate into higher risk-taking in nature by being more mobile while seeking out partners or valuable territories. Possible explanations include asset-protection, with OW animals being rather old with low residual reproductive value in spring. Therefore, OW may take higher risks during this season. Offspring born in spring encounter a lower population density and may have higher reproductive value than offspring of later cohorts. A constant connection between life history and animal personality, as

  1. Seasonal and spatial variations in fish and macrocrustacean assemblage structure in Mad Island Marsh estuary, Texas

    Science.gov (United States)

    Akin, S.; Winemiller, K. O.; Gelwick, F. P.

    2003-05-01

    Fish and macrocrustacean assemblage structure was analyzed along an estuarine gradient at Mad Island Marsh (MIM), Matagorda Bay, TX, during March 1998-August 1999. Eight estuarine-dependent fish species accounted for 94% of the individual fishes collected, and three species accounted for 96% of macrocrustacean abundance. Consistent with evidence from other Gulf of Mexico estuarine studies, species richness and abundance were highest during late spring and summer, and lowest during winter and early spring. Sites near the bay supported the most individuals and species. Associations between fish abundance and environmental variables were examined with canonical correspondence analysis. The dominant gradient was associated with water depth and distance from the bay. The secondary gradient reflected seasonal variation and was associated with temperature, salinity, dissolved oxygen, and vegetation cover. At the scales examined, estuarine biota responded to seasonal variation more than spatial variation. Estuarine-dependent species dominated the fauna and were common throughout the open waters of the shallow lake during winter-early spring when water temperature and salinity were low and dissolved oxygen high. During summer-early fall, sub-optimal environmental conditions (high temperature, low DO) in upper reaches accounted for strong spatial variation in assemblage composition. Small estuarine-resident fishes and the blue crab ( Callinectes sapidus) were common in warm, shallow, vegetated inland sites during summer-fall. Estuarine-dependent species were common at deeper, more saline locations near the bay during this period. During summer, freshwater species, such as gizzard shad ( Dorosoma cepedianum) and gars ( Lepisosteus spp.), were positively associated with water depth and proximity to the bay. The distribution and abundance of fishes in MIM appear to result from the combined effects of endogenous, seasonal patterns of reproduction and migration operating on large

  2. Seasonal and geographical variation in heat tolerance and evaporative cooling capacity in a passerine bird.

    Science.gov (United States)

    Noakes, Matthew J; Wolf, Blair O; McKechnie, Andrew E

    2016-03-01

    Intraspecific variation in avian thermoregulatory responses to heat stress has received little attention, despite increasing evidence that endothermic animals show considerable physiological variation among populations. We investigated seasonal (summer versus winter) variation in heat tolerance and evaporative cooling in an Afrotropical ploceid passerine, the white-browed sparrow-weaver (Plocepasser mahali; ∼ 47 g) at three sites along a climatic gradient with more than 10 °C variation in mid-summer maximum air temperature (Ta). We measured resting metabolic rate (RMR) and total evaporative water loss (TEWL) using open flow-through respirometry, and core body temperature (Tb) using passive integrated transponder tags. Sparrow-weavers were exposed to a ramped profile of progressively higher Ta between 30 and 52 °C to elicit maximum evaporative cooling capacity (N=10 per site per season); the maximum Ta birds tolerated before the onset of severe hyperthermia (Tb ≈ 44 °C) was considered to be their hyperthermia threshold Ta (Ta,HT). Our data reveal significant seasonal acclimatisation of heat tolerance, with a desert population of sparrow-weavers reaching significantly higher Ta in summer (49.5 ± 1.4 °C, i.e. higher Ta,HT) than in winter (46.8 ± 0.9 °C), reflecting enhanced evaporative cooling during summer. Moreover, desert sparrow-weavers had significantly higher heat tolerance and evaporative cooling capacity during summer compared with populations from more mesic sites (Ta,HT=47.3 ± 1.5 and 47.6 ± 1.3 °C). A better understanding of the contributions of local adaptation versus phenotypic plasticity to intraspecific variation in avian heat tolerance and evaporative cooling capacity is needed for modelling species' responses to changing climates. © 2016. Published by The Company of Biologists Ltd.

  3. SU-E-T-136: Assessment of Seasonal Linear Accelerator Output Variations and Associated Impacts

    International Nuclear Information System (INIS)

    Bartolac, S; Letourneau, D

    2015-01-01

    Purpose: Application of process control theory in quality assurance programs promises to allow earlier identification of problems and potentially better quality in delivery than traditional paradigms based primarily on tolerances and action levels. The purpose of this project was to characterize underlying seasonal variations in linear accelerator output that can be used to improve performance or trigger preemptive maintenance. Methods: Review of runtime plots of daily (6 MV) output data acquired using in house ion chamber based devices over three years and for fifteen linear accelerators of varying make and model were evaluated. Shifts in output due to known interventions with the machines were subtracted from the data to model an uncorrected scenario for each linear accelerator. Observable linear trends were also removed from the data prior to evaluation of periodic variations. Results: Runtime plots of output revealed sinusoidal, seasonal variations that were consistent across all units, irrespective of manufacturer, model or age of machine. The average amplitude of the variation was on the order of 1%. Peak and minimum variations were found to correspond to early April and September, respectively. Approximately 48% of output adjustments made over the period examined were potentially avoidable if baseline levels had corresponded to the mean output, rather than to points near a peak or valley. Linear trends were observed for three of the fifteen units, with annual increases in output ranging from 2–3%. Conclusion: Characterization of cyclical seasonal trends allows for better separation of potentially innate accelerator behaviour from other behaviours (e.g. linear trends) that may be better described as true out of control states (i.e. non-stochastic deviations from otherwise expected behavior) and could indicate service requirements. Results also pointed to an optimal setpoint for accelerators such that output of machines is maintained within set tolerances

  4. SU-E-T-136: Assessment of Seasonal Linear Accelerator Output Variations and Associated Impacts

    Energy Technology Data Exchange (ETDEWEB)

    Bartolac, S; Letourneau, D [Princess Margaret Cancer Centre, Toronto, Ontario (Canada); University of Toronto, Toronto, Ontario (Canada)

    2015-06-15

    Purpose: Application of process control theory in quality assurance programs promises to allow earlier identification of problems and potentially better quality in delivery than traditional paradigms based primarily on tolerances and action levels. The purpose of this project was to characterize underlying seasonal variations in linear accelerator output that can be used to improve performance or trigger preemptive maintenance. Methods: Review of runtime plots of daily (6 MV) output data acquired using in house ion chamber based devices over three years and for fifteen linear accelerators of varying make and model were evaluated. Shifts in output due to known interventions with the machines were subtracted from the data to model an uncorrected scenario for each linear accelerator. Observable linear trends were also removed from the data prior to evaluation of periodic variations. Results: Runtime plots of output revealed sinusoidal, seasonal variations that were consistent across all units, irrespective of manufacturer, model or age of machine. The average amplitude of the variation was on the order of 1%. Peak and minimum variations were found to correspond to early April and September, respectively. Approximately 48% of output adjustments made over the period examined were potentially avoidable if baseline levels had corresponded to the mean output, rather than to points near a peak or valley. Linear trends were observed for three of the fifteen units, with annual increases in output ranging from 2–3%. Conclusion: Characterization of cyclical seasonal trends allows for better separation of potentially innate accelerator behaviour from other behaviours (e.g. linear trends) that may be better described as true out of control states (i.e. non-stochastic deviations from otherwise expected behavior) and could indicate service requirements. Results also pointed to an optimal setpoint for accelerators such that output of machines is maintained within set tolerances

  5. Isotopic composition of water in precipitation due to seasonal variation and variation in intensity of rain fall at a place

    International Nuclear Information System (INIS)

    Singh, B.P.

    2015-01-01

    An attempt has been made to analyze the data to find the original precipitate on GMWL, when there is seasonal variation and variations in intensity of rain fall at the same longitude, latitude and altitude. This has been done using the data as available for each month, weighted average of month and individual year for δ 2 H and δ 18 O for a 10-year periods. Correlation equations between δ 2 H and δ 18 O are available giving slopes and intercepts on the δ 2 H axis for 10-year periods. The data of slope versus intercept for each month, weighted monthly average value and individual year are plotted to arrive at isotope composition of meteoric water δ 18 O and δ 2 H, the method suggested by (Singh B.P. 2013, Isotopic composition of water in precipitation in a region or place, Applied Radiation and Isotopes, vol. 75, pp. 22–25; Singh B.P. 2014, Isotopic composition of river water across a continent, Applied Radiation and Isotopes, vol. 85, pp. 14–18). The results of the original meteoric isotopic composition of water are within the experimental errors as analyzed on a yearly basis, the average of each month of yearly basis and on the basis of each month and also some different amounts of precipitation giving the same value of δ 18 O=−16.72 and δ 2 H=−129.86 on GMWL. - Highlights: • New pattern, plot of slope versus intercept between δ 18 O and δ 2 H at the same location for seasons and rainfall are given. • These patterns are analyzed to arrive at the original isotopic composition to be on GMWL. • It is found that the original isotopic composition is same for different seasons and amount of rainfall

  6. Coupled effects of natural and anthropogenic controls on seasonal and spatial variations of river water quality during baseflow in a coastal watershed of Southeast China.

    Directory of Open Access Journals (Sweden)

    Jinliang Huang

    Full Text Available Surface water samples of baseflow were collected from 20 headwater sub-watersheds which were classified into three types of watersheds (natural, urban and agricultural in the flood, dry and transition seasons during three consecutive years (2010-2012 within a coastal watershed of Southeast China. Integrating spatial statistics with multivariate statistical techniques, river water quality variations and their interactions with natural and anthropogenic controls were examined to identify the causal factors and underlying mechanisms governing spatiotemporal patterns of water quality. Anthropogenic input related to industrial effluents and domestic wastewater, agricultural activities associated with the precipitation-induced surface runoff, and natural weathering process were identified as the potential important factors to drive the seasonal variations in stream water quality for the transition, flood and dry seasons, respectively. All water quality indicators except SRP had the highest mean concentrations in the dry and transition seasons. Anthropogenic activities and watershed characteristics led to the spatial variations in stream water quality in three types of watersheds. Concentrations of NH(4(+-N, SRP, K(+, COD(Mn, and Cl- were generally highest in urban watersheds. NO3(-N Concentration was generally highest in agricultural watersheds. Mg(2+ concentration in natural watersheds was significantly higher than that in agricultural watersheds. Spatial autocorrelations analysis showed similar levels of water pollution between the neighboring sub-watersheds exhibited in the dry and transition seasons while non-point source pollution contributed to the significant variations in water quality between neighboring sub-watersheds. Spatial regression analysis showed anthropogenic controls played critical roles in variations of water quality in the JRW. Management implications were further discussed for water resource management. This research

  7. Dispersion Measure Variation of Repeating Fast Radio Burst Sources

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yuan-Pei; Zhang, Bing, E-mail: yypspore@gmail.com, E-mail: zhang@physics.unlv.edu [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China)

    2017-09-20

    The repeating fast radio burst (FRB) 121102 was recently localized in a dwarf galaxy at a cosmological distance. The dispersion measure (DM) derived for each burst from FRB 121102 so far has not shown significant evolution, even though an apparent increase was recently seen with newly detected VLA bursts. It is expected that more repeating FRB sources may be detected in the future. In this work, we investigate a list of possible astrophysical processes that might cause DM variation of a particular FRB source. The processes include (1) cosmological scale effects such as Hubble expansion and large-scale structure fluctuations; (2) FRB local effects such as gas density fluctuation, expansion of a supernova remnant (SNR), a pulsar wind nebula, and an H ii region; and (3) the propagation effect due to plasma lensing. We find that the DM variations contributed by the large-scale structure are extremely small, and any observable DM variation is likely caused by the plasma local to the FRB source. In addition to mechanisms that decrease DM over time, we suggest that an FRB source in an expanding SNR around a nearly neutral ambient medium during the deceleration (Sedov–Taylor and snowplow) phases or in a growing H ii region can increase DM. Some effects (e.g., an FRB source moving in an H ii region or plasma lensing) can produce either positive or negative DM variations. Future observations of DM variations of FRB 121102 and other repeating FRB sources can provide important clues regarding the physical origin of these sources.

  8. Dispersion Measure Variation of Repeating Fast Radio Burst Sources

    International Nuclear Information System (INIS)

    Yang, Yuan-Pei; Zhang, Bing

    2017-01-01

    The repeating fast radio burst (FRB) 121102 was recently localized in a dwarf galaxy at a cosmological distance. The dispersion measure (DM) derived for each burst from FRB 121102 so far has not shown significant evolution, even though an apparent increase was recently seen with newly detected VLA bursts. It is expected that more repeating FRB sources may be detected in the future. In this work, we investigate a list of possible astrophysical processes that might cause DM variation of a particular FRB source. The processes include (1) cosmological scale effects such as Hubble expansion and large-scale structure fluctuations; (2) FRB local effects such as gas density fluctuation, expansion of a supernova remnant (SNR), a pulsar wind nebula, and an H ii region; and (3) the propagation effect due to plasma lensing. We find that the DM variations contributed by the large-scale structure are extremely small, and any observable DM variation is likely caused by the plasma local to the FRB source. In addition to mechanisms that decrease DM over time, we suggest that an FRB source in an expanding SNR around a nearly neutral ambient medium during the deceleration (Sedov–Taylor and snowplow) phases or in a growing H ii region can increase DM. Some effects (e.g., an FRB source moving in an H ii region or plasma lensing) can produce either positive or negative DM variations. Future observations of DM variations of FRB 121102 and other repeating FRB sources can provide important clues regarding the physical origin of these sources.

  9. Predicting seasonal variations in coastal seabird habitats in the English Channel and the Bay of Biscay

    Science.gov (United States)

    Virgili, A.; Lambert, C.; Pettex, E.; Dorémus, G.; Van Canneyt, O.; Ridoux, V.

    2017-07-01

    Seabirds, like all animals, have to live in suitable habitats to fulfil their energetic needs for both somatic and reproductive growth and maintenance. Apart from migration trips, all coastal seabirds are linked to the coast, because they need to return daily to land for resting or breeding. Their use of marine habitats strongly depends on their biology, but also on environmental conditions, and can be described using habitat models. This study aimed to: (1) identify the processes that mostly influence seabird distributions along the coasts of the English Channel and the Bay of Biscay; (2) determine seasonal variations of these processes, (3) provide prediction maps that describe the species distributions. We collected data of coastal seabird sightings from aerial surveys carried out in the English Channel and the eastern North Atlantic in the winter 2011-2012 and summer 2012. We classified seabirds into morphological groups and described their habitats using physiographic and oceanographic variables in Generalised Additive Models (GAMs). Finally, we produced maps of predicted distributions by season for each group. The distributions of coastal seabirds were essentially determined by the distance to the nearest coast, with a weaker influence of oceanographic variables. The nature of the substrate, sand or rock, combined with the timing of reproduction, also contributed to determine seasonal at-sea distributions for some species. The highest densities were predicted near the coast, particularly in bays and estuaries for strictly coastal species with possible variations depending on the season. From this study, we were able to predict the seasonal distribution of the studied species according to varying environmental parameters that changed over time, allowing us to understand better their behaviour and ecology.

  10. Seasonal variations in dissolved neodymium isotope composition in the Bay of Bengal

    Science.gov (United States)

    Yu, Zhaojie; Colin, Christophe; Meynadier, Laure; Douville, Eric; Dapoigny, Arnaud; Reverdin, Gilles; Wu, Qiong; Wan, Shiming; Song, Lina; Xu, Zhaokai; Bassinot, Frank

    2017-12-01

    Constraining the dissolved neodymium (Nd) cycle in the ocean is paramount for using Nd isotopic composition (εNd) as a tracer to reconstruct deep-sea paleocirculations or continental weathering on different time scales. Dissolved εNd has been measured in seawater samples from six hydrological stations collected along ∼89°E North-South transect in the Bay of Bengal (BoB) in order to assess the impact of seasonal freshwater and sediment discharges from the continental river systems. Seawater samples collected in this study during June 2012 reveal more radiogenic εNd (a difference of ∼2 Epsilon units for the upper 2000 m, and ∼0.5 Epsilon unit below 2000 m) and ∼3-8 pmol/kg lower Nd concentrations than the reported values of nearby seawater samples collected in November 2008. These observations are most plausibly explained by a seasonal variations in dissolved Nd concentrations and εNd in the BoB, induced by seasonal variations in the freshwater and sediment discharges from the Ganges-Brahmaputra (G-B) river system. However, we cannot entirely exclude the possibility of spatial differences given that the water stations collected in this study are not exactly the same positions collected in November 2008. A two-box model suggests, (1) the particulate Nd inputs from the G-B river system mainly control the seasonal shift of εNd observed in the BoB seawater, and (2) a very rapid Nd exchange exists between lithogenic particles and seawater (at least on the scale of a few months). Seasonal changes in seawater εNd may also occur in other marginal seas and in the outflows of major rivers, and these need to be taken into account when using the εNd proxy in the ocean.

  11. Sources of Variation in the Age Composition of Sandeel Landings

    DEFF Research Database (Denmark)

    Kvist, Trine; Gislason, Hannes; Thyregod, Poul

    2001-01-01

    in the samples is significantly lower in the start and end of the fishing season. This suggests that the older sandeel are available to the fishery for a shorter time period that the 1-group. Significant differences are found in the age composition between the four laboratories involved in the age determination......The variation of the age composition of the landings of lesser sandeel in the Danish industrial fishery in the North Sea over the period From 1984-1993 is analysed by continuation-ratio logits and generalised linear models. The analysis takes the multinomial characteristics of the age composition....... Although the variation between ICES statistical rectangles is substantial there is a significant difference between the age composition in the northern and southern part of the North Sea. However, only one of the three finer geographical stratifications proposed to improve the assessment results...

  12. Seasonal climate variation and caribou availability: Modeling sequential movement using satellite-relocation data

    Science.gov (United States)

    Nicolson, Craig; Berman, Matthew; West, Colin Thor; Kofinas, Gary P.; Griffith, Brad; Russell, Don; Dugan, Darcy

    2013-01-01

    Livelihood systems that depend on mobile resources must constantly adapt to change. For people living in permanent settlements, environmental changes that affect the distribution of a migratory species may reduce the availability of a primary food source, with the potential to destabilize the regional social-ecological system. Food security for Arctic indigenous peoples harvesting barren ground caribou (Rangifer tarandus granti) depends on movement patterns of migratory herds. Quantitative assessments of physical, ecological, and social effects on caribou distribution have proven difficult because of the significant interannual variability in seasonal caribou movement patterns. We developed and evaluated a modeling approach for simulating the distribution of a migratory herd throughout its annual cycle over a multiyear period. Beginning with spatial and temporal scales developed in previous studies of the Porcupine Caribou Herd of Canada and Alaska, we used satellite collar locations to compute and analyze season-by-season probabilities of movement of animals between habitat zones under two alternative weather conditions for each season. We then built a set of transition matrices from these movement probabilities, and simulated the sequence of movements across the landscape as a Markov process driven by externally imposed seasonal weather states. Statistical tests showed that the predicted distributions of caribou were consistent with observed distributions, and significantly correlated with subsistence harvest levels for three user communities. Our approach could be applied to other caribou herds and could be adapted for simulating the distribution of other ungulates and species with similarly large interannual variability in the use of their range.

  13. The gut microbiota appears to compensate for seasonal diet variation in the wild black howler monkey (Alouatta pigra).

    Science.gov (United States)

    Amato, Katherine R; Leigh, Steven R; Kent, Angela; Mackie, Roderick I; Yeoman, Carl J; Stumpf, Rebecca M; Wilson, Brenda A; Nelson, Karen E; White, Bryan A; Garber, Paul A

    2015-02-01

    For most mammals, including nonhuman primates, diet composition varies temporally in response to differences in food availability. Because diet influences gut microbiota composition, it is likely that the gut microbiota of wild mammals varies in response to seasonal changes in feeding patterns. Such variation may affect host digestive efficiency and, ultimately, host nutrition. In this study, we investigate the temporal variation in diet and gut microbiota composition and function in two groups (N = 13 individuals) of wild Mexican black howler monkeys (Alouatta pigra) over a 10-month period in Palenque National Park, Mexico. Temporal changes in the relative abundances of individual bacterial taxa were strongly correlated with changes in host diet. For example, the relative abundance of Ruminococcaceae was highest during periods when energy intake was lowest, and the relative abundance of Butyricicoccus was highest when young leaves and unripe fruit accounted for 68 % of the diet. Additionally, the howlers exhibited increased microbial production of energy during periods of reduced energy intake from food sources. Because we observed few changes in howler activity and ranging patterns during the course of our study, we propose that shifts in the composition and activity of the gut microbiota provided additional energy and nutrients to compensate for changes in diet. Energy and nutrient production by the gut microbiota appears to provide an effective buffer against seasonal fluctuations in energy and nutrient intake for these primates and is likely to have a similar function in other mammal species.

  14. Diurnal and Seasonal Variations in Mid-Latitude Geomagnetic Field During International Quiet Days: BOH Magnetometer

    Directory of Open Access Journals (Sweden)

    Junga Hwang

    2012-12-01

    Full Text Available Korea Astronomy and Space Science Institute researchers have installed and operated magnetometers at Bohyunsan Observatory to measure the Earth's magnetic field variations in South Korea. In 2007, we installed a fluxgate magnetometer (RFP-523C to measure H, D, and Z components of the geomagnetic field. In addition, in 2009, we installed a Overhauser proton sensor to measure the absolute total magnetic field F and a three-axis magneto-impedance sensor for spectrum analysis. Currently three types of magnetometer data have been accumulated. In this paper, we use the H, D, Z components of fluxgate magnetometer data to investigate the characteristics of mid-latitude geomagnetic field variation. To remove the temporary changes in Earth’s geomagnetic filed by space weather, we use the international quiet days’ data only. In other words, we performed a superposed epoch analysis using five days per each month during 2008-2011. We find that daily variations of H, D, and Z shows similar tendency compared to previous results using all days. That is, H, D, Z all three components’ quiet intervals terminate near the sunrise and shows maximum 2-3 hours after the culmination and the quiet interval start from near the sunset. Seasonal variations show similar dependences to the Sun. As it becomes hot season, the geomagnetic field variation’s amplitude becomes large and the quiet interval becomes shortened. It is well-known that these variations are effects of Sq current system in the Earth’s atmosphere. We confirm that the typical mid-latitude geomagnetic field variations due to the Sq current system by excluding all possible association with the space weather.

  15. Determinants, reproducibility, and seasonal variation of ergosterol levels in house dust.

    Science.gov (United States)

    Leppänen, H K; Nevalainen, A; Vepsäläinen, A; Roponen, M; Täubel, M; Laine, O; Rantakokko, P; von Mutius, E; Pekkanen, J; Hyvärinen, A

    2014-06-01

    This study aimed to clarify the determinants that affect the concentrations of ergosterol and viable fungi in house dust and to examine the seasonal variation and reproducibility of ergosterol concentrations indoors. In studying the determinants, dust samples from living room floors and vacuum cleaner dust bags were collected from 107 farming and 105 non-farming homes. Ergosterol levels were determined with gas chromatography-mass spectrometry,and the dust bag dust was cultivated for enumeration of fungal genera. Lifestyle and environmental factors, for example using of the fireplace, and visible mold observations in homes, explained 20–26% of the variation of fungal concentrations. For the reproducibility study, samples were collected from five urban homes in four different seasons. The reproducibility of ergosterol determinations within a sample was excellent (ICC = 89.8) for floor dust and moderate (ICC = 63.8) for dust bag dust, but poor when sampling the same home throughout a year (ICC = 31.3 and 12.6, respectively) due to large temporal variation in ergosterol concentrations. In conclusion, environmental characteristics only partially predicted the variation of fungal concentrations. Based on these studies, we recommend repeated sampling of dust over time if one seeks to adequately describe overall fungal levels and exposure in a home. This study shows that levels of ergosterol and viable fungi in house dust are related to visible mold observations. Only 20% of the variation in fungal levels can be explained with questionnaires, and therefore, environmental samples need to be taken in addition. Reproducibility of ergosterol determination was excellent for floor dust, and thus, ergosterol measurements from floor dust samples could be suitable for assessing the fungal load in building investigations. The temporal variation needs to be taken into account when describing the ergosterol concentration of urban homes.

  16. Seasonal mortality variations of cardiovascular, respiratory and malignant diseases in the City of Belgrade

    Directory of Open Access Journals (Sweden)

    Stanišić-Stojić Svetlana

    2016-01-01

    Full Text Available The main purpose of this paper is to examine seasonal variations in mortality resulting from cardiovascular diseases, respiratory diseases and cancer, as well as to provide a review of environmental factors underlying such phenomenon. The herein presented study was conducted on the territory of Belgrade based on the data on daily mortality rates obtained from the Institute of Public Health in Belgrade for the period 2009-2014, as well as the data on annual mortality rates provided by the Statistical Office of the Republic of Serbia for the period 2000-2014. The analysis of mortality variations was performed by the use of Theil-Sen method, smooth trend method and cubic spline interpolation, whereas desriptive tools, such as winter/summer ratio and dissimilarity index, were used to examine the seasonal pattern. According to the Institute of Public Health, over 113430 deaths were registered in Belgrade area for the period 2009-2014, out of which 53.25% is attributed to cardiovascular diseases, 4.01% to respiratory diseases and 27.50% to cancer. The annual mortality rates caused by cardiovascular diseases and cancer on the territory of Belgrade are among the highest ranking in Europe. The leading causes of death in the observed period included: cardiomyopathy, heart attack and stroke with accompanying complications, breast cancer in women, prostate and colorectal cancer in men, lung and bronchus cancer for both genders, and chronic obstructive pulmonary disease. Cardiovascular and respiratory mortality rates are significantly higher among people aged 65 and over, whereas more than one third of deaths caused by cancer is observed among younger people aged between 45 and 64 years. Research results show that seasonal variations were most pronounced in mortality resulting from cardiovascular and respiratory diseases, with highest mortality rates recorded in February and March and lowest during the summer season. Also, the number of deaths due to

  17. Seasonal and Milking-to-Milking Variations in Cow Milk Fat, Protein and Somatic Cell Counts

    Directory of Open Access Journals (Sweden)

    Elena Raluca PAVEL

    2011-05-01

    Full Text Available The first objective of this study was to examine milking-to-milking variations in milk fat, protein and SCC (somatic cell count. The second objective of this study was to examine variations of milk components (fat, protein and SCC over a period of six months (April-September 2010 at Agricultural Research Development Station Simnic. A total of 128 milk samples (64 morning milking and 64 evening milking ones from milk bulk tank commingled from 904 Holstein cows, were collected and analyzed for fat, protein and SCC. Data suggested that milking period effects milk fat, making the fat percentage lower in the morning compared with the evening milking period, effect which was not similar in protein content. Seasonal differences in milk fat and protein were also investigated. The season of year had influenced SCC, fat and protein: SCC increased, while fat and protein decreased. The period of the day when milking took place and the season influenced fat, protein and SCC, but the composition of milk, as well as its hygienic quality, fell within the aplicabile standards for raw milk.

  18. Seasonal and Milking-to-Milking Variations in Cow Milk Fat, Protein and Somatic Cell Counts

    Directory of Open Access Journals (Sweden)

    Elena Raluca PAVEL

    2011-05-01

    Full Text Available The first objective of this study was to examine milking-to-milking variations in milk fat, protein and SCC (somatic cell count. The second objective of this study was to examine variations of milk components (fat, protein and SCC over a period of six months (April-September 2010 at Agricultural Research Development Station Simnic. A total of 128 milk samples (64 morning milking and 64 evening milking ones from milk bulk tank commingled from 90�4 Holstein cows, were collected and analyzed for fat, protein and SCC. Data suggested that milking period effects milk fat, making the fat percentage lower in the morning compared with the evening milking period, effect which was not similar in protein content. Seasonal differences in milk fat and protein were also investigated. The season of year had influenced SCC, fat and protein: SCC increased, while fat and protein decreased. The period of the day when milking took place and the season influenced fat, protein and SCC, but the composition of milk, as well as its hygienic quality, fell within the aplicabile standards for raw milk.

  19. Analysis of trends and seasonal variation in primary cutaneous melanoma: an Irish study.

    LENUS (Irish Health Repository)

    Downes, M R

    2010-11-10

    A seasonal variation in the presentation of cutaneous melanoma has been documented in several studies. We performed a retrospective review of primary cutaneous melanomas (n = 263) from our institution to examine whether the seasonal patterns of presentation noted in the literature would be similar in Ireland, a climate with low ambient sunshine. A summer : winter ratio was determined for age, gender, subtype, location and Breslow thickness. We found an increase in total numbers of melanomas, particularly in men. The summer : winter ratio was 2.39 for all patients (95% CI 1.60-3.57, P < 0.001), with seasonal variations noted for location, thickness and subtype (excluding lentigo). Melanomas presenting over the summer tended towards a greater Breslow thickness than did those presenting in winter. This subclassification of primary cutaneous melanoma with summer : winter ratios based on patient and tumour characteristics gave remarkably similar results to previously published reports, notwithstanding the low levels of annual ambient sunshine in Ireland.

  20. Seasonal variations in shallow Alaska seismicity and stress modulation from GRACE derived hydrological loading

    Science.gov (United States)

    Johnson, C. W.; Fu, Y.; Burgmann, R.

    2017-12-01

    Shallow (≤50 km), low magnitude (M≥2.0) seismicity in southern Alaska is examined for seasonal variations during the annual hydrological cycle. The seismicity is declustered with a spatio-temporal epidemic type aftershock sequence (ETAS) model. The removal of aftershock sequences allows detailed investigation of seismicity rate changes, as water and ice loads modulate crustal stresses throughout the year. The GRACE surface loads are obtained from the JPL mass concentration blocks (mascons) global land and ocean solutions. The data product is smoothed with a 9˚ Gaussian filter and interpolated on a 25 km grid. To inform the surface loading model, the global solutions are limited to the region from -160˚ to -120˚ and 50˚ to 70˚. The stress changes are calculated using a 1D spherical layered earth model at depth intervals of 10 km from 10 - 50 km in the study region. To evaluate the induced seasonal stresses, we use >30 years of earthquake focal mechanisms to constrain the background stress field orientation and assess the stress change with respect to the principal stress orientation. The background stress field is assumed to control the preferred orientation of faulting, and stress field perturbations are expected to increase or decrease seismicity. The number of excess earthquakes is calculated with respect to the background seismicity rates. Here, we present preliminary results for the shallow seismicity variations and quantify the seasonal stresses associated with changes in hydrological loading.

  1. Variations of annual and seasonal runoff in Guangdong Province, south China: spatiotemporal patterns and possible causes

    Science.gov (United States)

    Zhang, Qiang; Xiao, Mingzhong; Singh, Vijay P.; Xu, Chong-Yu; Li, Jianfeng

    2015-06-01

    In this study, we thoroughly analyzed spatial and temporal distributions of runoff and their relation with precipitation changes based on monthly runoff dataset at 25 hydrological stations and monthly precipitation at 127 stations in Guangdong Province, south China. Trends of the runoff and precipitation are detected using Mann-Kendall trend test technique. Correlations between runoff and precipitation are tested using Spearman's and Pearson's correlation coefficients. The results indicate that: (1) annual maximum monthly runoff is mainly in decreasing tendency and significant increasing annual minimum monthly runoff is observed in the northern and eastern Guangdong Province. In addition, annual mean runoff is observed to be increasing at the stations located in the West and North Rivers and the coastal region; (2) analysis of seasonal runoff variations indicates increasing runoff in spring, autumn and winter. Wherein, significant increase of runoff is found at 8 stations and only 3 stations are dominated by decreasing runoff in winter; (3) runoff changes of the Guangdong Province are mainly the results of precipitation changes. The Guangdong Province is wetter in winter, spring and autumn. Summer is coming to be drier as reflected by decreasing runoff in the season; (4) both precipitation change and water reservoirs also play important roles in the increasing of annual minimum monthly streamflow. Seasonal shifts of runoff variations may pose new challenges for the water resources management under the influences of climate changes and intensifying human activities.

  2. Epsodic paroxysmal hemicrania with seasonal variation: case report and the EPH-cluster headache continuum hypothesis

    Directory of Open Access Journals (Sweden)

    Veloso Germany Gonçalves

    2001-01-01

    Full Text Available Episodic paroxysmal hemicrania (EPH is a rare disorder characterized by frequent, daily attacks of short-lived, unilateral headache with accompanying ipsilateral autonomic features. EPH has attack periods which last weeks to months separated by remission intervals lasting months to years, however, a seasonal variation has never been reported in EPH. We report a new case of EPH with a clear seasonal pattern: a 32-year-old woman with a right-sided headache for 17 years. Pain occurred with a seasonal variation, with bouts lasting one month (usually in the first months of the year and remission periods lasting around 11 months. During these periods she had headache from three to five times per day, lasting from 15 to 30 minutes, without any particular period preference. There were no precipitating or aggravating factors. Tearing and conjunctival injection accompanied ipsilaterally the pain. Previous treatments provided no pain relief. She completely responded to indomethacin 75 mg daily. After three years, the pain recurred with longer attack duration and was just relieved with prednisone. We also propose a new hypothesis: the EPH-cluster headache continuum.

  3. Seasonal variation of Legionella in Taiwan's reservoir and its relationships with environmental factors.

    Science.gov (United States)

    Kao, Po-Min; Hsu, Bing-Mu; Chang, Tien-Yu; Hsu, Tsui-Kang; Tzeng, Kai-Jiun; Huang, Yu-Li

    2015-04-01

    In this study, the presence of Legionella in major water reservoirs of Taiwan was examined with respect to seasonal variation, geographical variation, and water quality parameters using TaqMan real-time qPCR. Water samples were collected quarterly at 19 reservoirs in Taiwan between November 2012 and August 2013. The detection rate for Legionella was 35.5% (27/76), and Legionella was detected in all seasons. The Legionella concentration was relatively high in spring and summer, reaching 3.86 × 10(8) and 7.35 × 10(8) cells/L, respectively. By sampling the area, Legionella was detected at a higher proportion in reservoirs in the northern and southern areas, and the difference was consistent in all seasons. Significant association was found between detection of Legionella and various water quality parameters, including conductivity, chlorophyll a, and dissolved oxygen (Mann-Whitney U test, P Legionella detection with pH (P = 0.030, R = -0.497) and dissolved oxygen (P = 0.007, R = -0.596) in fall and positive correlation with Carlson's trophic state index (P = 0.049, R = 0.457) in spring. The identified species included Legionella pneumophila and Legionella drancourtii. The detection of Legionella in reservoirs was indicative of a potential public health risk and should be further evaluated.

  4. Frequency of typhoid fever and its association with seasonal variations in Taxila, Pakistan

    Directory of Open Access Journals (Sweden)

    Naeem Bukhari

    2016-08-01

    Full Text Available Objective: To analyse seropositivity rates of salmonella with seasonal variations in the population of Taxila and the surrounding rural areas. Methods: The study was conducted among 760 suspected patients with symptoms of fever, headache, nausea and decreased white blood cells count screened for the typhoid fever. Blood samples collected from the suspected patients were tested for seropositivity by slide agglutination (Widal test and Immunochromatographic test, i.e. Typhidot. Results: From overall 760 suspected patients of typhoid fever only 192 (25.26% samples were positive for Widal and Typhidot test. The peak seropositivity rates were identified during the months of April–June, while decreased cases were observed from January to March. Age wise distribution of typhoid fever reflected that age groups of 10–15 years and 25–35 years were at higher risks of developing enteric fever with respect to age groups of 5–10 years and 61–70 years, respectively. On gender basis evaluation, females (24.49% were slightly at low risks of developing typhoid fever than males (25.9%. Conclusions: The present study highlights a higher burden of typhoid fever in Taxila and the surrounding areas population that directly reflects the poor hygienic condition and contamination of drinking water. The frequency of typhoid fever fluctuates with seasonal variations as higher rates found during the summer as compared to winter season.

  5. Man biting rate seasonal variation of malaria vectors in Roraima, Brazil

    Directory of Open Access Journals (Sweden)

    Fábio Saito Monteiro de Barros

    2007-06-01

    Full Text Available Malaria control has been directed towards regional actions where more detailed knowledge of local determinants of transmission is of primary importance. This is a short report on range distribution and biting indices for Anopheles darlingi and An. albitarsis during the dry and rainy season that follows river level variation in a savanna/alluvial forest malaria system area in the Northern Amazon Basin. Distribution range and adult biting indices were at their highest during the rainy season for both An. darlingi and An. albitarsis. During the rainy season the neighboring alluvial forest was extensively flooded. This coincided with highest rates in malaria transmission with case clustering near the river. As the river receded, anopheline distribution range and density decreased. This decrease in distribution and density corresponded to a malaria decrease in the near area. An exponential regression function was derived to permit estimations of An. darlingi distribution over specified distances. Anopheline spatio-temporal variations lead to uneven malaria case distribution and are of important implications for control strategies.

  6. Recent changes in seasonal variations of climate within the range of northern caribou populations

    Directory of Open Access Journals (Sweden)

    Paul H. Whitfield

    2005-05-01

    Full Text Available The Arctic is one region where it is expected that the impacts of a globally changing climate will be readily observed. We present results that indicate that climate derivatives of potential significance to caribou changed during the past 50 years. Many temperature derivatives reflect the increasing overall temperature in the Arctic such as decreases in the number of days with low temperatures, increases in the number of days with thaw, and days with extremely warm temperatures. Other derivatives reflect changes in the precipitation regime such as days with heavy precipitation and number of days when rain fell on snow. Our results indicate that specific caribou herds from across the Arctic were subjected to different variations of these derivatives in different seasons in the recent past. Examination of temperature and precipitation at finer time-steps than annual or monthly means, shows that climatic variations in the region are neither consistent through the seasons nor across space. Decadal changes in seasonal patterns of temperature and precipitation are shown for selected herds. A process for assessing caribou-focused climate derivatives is proposed.

  7. Investigation on seasonal variation of thermal-induced strain in flexible pavements based on field and laboratory measurements

    Directory of Open Access Journals (Sweden)

    Simita Biswas

    2016-09-01

    Full Text Available Pavement temperature variation has a large influence on the structural response of flexible pavements. Daily and seasonal temperature fluctuation causes expansion and contraction of pavement material, which then leads to the generation of thermal strain. In this study, field observation and laboratory tests were conducted to investigate seasonal variation of thermal-induced strain in flexible pavement. Field observations were conducted at the Integrated Road Research Facility (IRRF’s test road in Edmonton, Alberta, Canada, which is fully equipped with structural and environmental monitoring instruments. The main objective of the field study was to compare the variation of thermal-induced strain in warm and cold seasons. Field results indicated that thermal-induced strain is 1.4–2.0 times greater in cold seasons than in warm seasons following the same pavement temperature variations; however, strain generation rate was greater in warm seasons. Laboratory testing of asphalt slab and cylindrical samples produced comparable ratios. Moreover, field observation and laboratory testing showed a similar trend of temperature and thermal strain variations. Keywords: Thermal-induced strain, Asphalt strain gauge, Field observation, Flexible pavement, Laboratory testing, Seasonal variation

  8. Seasonal variation and chemical characterization of PM2.5 in northwestern Philippines

    Science.gov (United States)

    Bagtasa, Gerry; Cayetano, Mylene G.; Yuan, Chung-Shin

    2018-04-01

    The seasonal and chemical characteristics of fine particulate matter (PM2.5) were investigated in Burgos, Ilocos Norte, located at the northwestern edge of the Philippines. Each 24 h sample of fine aerosol was collected for four seasons. Fine particulate in the region shows strong seasonal variation in both concentration and composition. Highest mass concentration was seen during the boreal spring season with a mean mass concentration of 21.6 ± 6.6 µg m-3, and lowest was in fall with a mean concentration of 8.4 ± 2.3 µg m-3. Three-day wind back trajectory analysis of air mass reveals the influence of the northwestern Pacific monsoon regimes on PM2.5 concentration. During southwest monsoon, sea salt was the dominant component of fine aerosols carried by moist air from the South China Sea. During northeast monsoon, on the other hand, both wind and receptor model analysis showed that higher particulate concentration was due to the long-range transport (LRT) of anthropogenic emissions from northern East Asia. Overall, sea salt and soil comprise 33 % of total PM2.5 concentration, while local biomass burning makes up 33 %. LRT of industrial emission, solid waste burning and secondary sulfate from East Asia have a mean contribution of 34 % to the total fine particulate for the whole sampling period.

  9. Seasonal variation of serum biochemical values of Amazonian snakes (Boa constrictor constrictor kept in captivity

    Directory of Open Access Journals (Sweden)

    Dennis José da Silva Lima

    2012-11-01

    Full Text Available In northern Brazil, the seasons are not well defined compared to the South and Southeast regions, due to a hot and humid equatorial climate with a rainy season, known as the Amazonian winter, and a period with less rain, known as the Amazonian summer. The goal of this study was to evaluate the biochemical variation of serum from the Amazon Boa constrictor by correlating the values with the seasons of the region. A biochemical analysis of the serum was performed (AST, ALT, LDH, ALP, calcium, uric acid, phosphorus, total protein, albumin and globulin using 31 individuals of Boa constrictor constrictor, which were kept in captivity. It was observed that eight of the ten parameters were higher in the winter compared to the summer (total protein, albumin, globulin, ALT, AST, ALP, LDH and calcium. The ALT, AST and calcium values had statistically significant differences for the summer and winter, while the other parameters appear to be influenced by seasonality. This was the first study of snakes kept in captivity that analyzed the serum chemistry profile of Boa constrictor constrictor from the state of Pará, Brazil.

  10. Diel and seasonal variation in food habits of Atlantic salmon parr in a small stream

    Science.gov (United States)

    Grader, M.; Letcher, B.H.

    2006-01-01

    The diel and seasonal food habits of young-of-year (YOY) and post-young-of-year (PYOY) Atlantic salmon (Salmo salar) parr were assayed over the course of 11 months in the West Brook, Massachusetts USA. Gut fullness of YOY salmon did not vary significantly among months. PYOY salmon exhibited significant seasonal differences in gut fullness, with peak fullness occurring in the spring and late fall. Significant diel differences in PYOY gut fullness occurred in June and April, with peak fullness always occurring at dawn. Prey composition varied substantially among months. Dominant prey items of PYOY salmon were baetid mayflies in June, July, and August, limnephilid caddisflies in October and November, and ephemerellid mayflies in February and April. Few differences in prey composition between PYOY and YOY salmon were observed. Fish growth was unrelated to prey availability, but gut fullness explained up to 97% of growth variation across seasons. Results suggest that spring and fall are critical periods of feeding for PYOY salmon and that diel feeding intensity shifts seasonally.

  11. Prevalence of antibiotic residues in commercial milk and its variation by season and thermal processing methods

    Directory of Open Access Journals (Sweden)

    Fathollah Aalipour

    2013-01-01

    Full Text Available Aims: In this study, the prevalence of antibiotic residues in pasteurized and sterilized commercial milk available in Shahre-kourd, Iran, was investigated. In addition, the influence of seasonal temperature changes on the prevalence of contamination was studied. Materials and Methods: Commercial milk samples of 187, including 154 pasteurized and 33 sterilized, milk samples were collected from the market between early January 2012 and late July of the same year. The presence of antibiotic residues was detected using the microbiological detection test kit, Eclipse 100, as a semi-quantitative method. Results: The results showed that 37 of the samples (19.8% have contained antibiotic residues above the European Union Maximum Residues Limits (EU-MRLs, of which 28 samples (14.97% were found to be contaminated but at the concentrations below the EU-MRLs. There was no significant difference between the contamination rate of pasteurized and Ultra High Temperature (UHT-sterilized samples. Similarly, variation of weather temperature with seasons had no effect on the contamination prevalence of milk samples ( P > 0.05. Conclusion: Based on the result of this study, antibiotics residues were present in the majority of milk samples. Neither the season nor the type of thermal processing of the commercial milks had noticeable impact on the prevalence level of the milk samples. However, an increasing trend of prevalence level for antibiotic residues was observed with increasing the temperature through the warm season.

  12. Seasonal variation of carbon fluxes in a sparse savanna in semi arid Sudan.

    Science.gov (United States)

    Ardö, Jonas; Mölder, Meelis; El-Tahir, Bashir Awad; Elkhidir, Hatim Abdalla Mohammed

    2008-12-01

    2005. The small sink during the dry season is surprising and similar dry season sinks have not to our knowledge been reported from other similar savanna ecosystems and could have potential management implications for agroforestry. A strong response of NEE versus small changes in plant available soil water content was found. Collection and analysis of flux data for several consecutive years including variations in precipitation, available soil moisture and labile soil carbon are needed for understanding the year to year variation of the carbon budget of this grass land/sparse savanna site in semi arid Sudan.

  13. Seasonal variation of carbon fluxes in a sparse savanna in semi arid Sudan

    Directory of Open Access Journals (Sweden)

    El-Tahir Bashir

    2008-12-01

    was a sink of carbon both during the dry and wet season 2005. The small sink during the dry season is surprising and similar dry season sinks have not to our knowledge been reported from other similar savanna ecosystems and could have potential management implications for agroforestry. A strong response of NEE versus small changes in plant available soil water content was found. Collection and analysis of flux data for several consecutive years including variations in precipitation, available soil moisture and labile soil carbon are needed for understanding the year to year variation of the carbon budget of this grass land/sparse savanna site in semi arid Sudan.

  14. Diversity in plant hydraulic traits explains seasonal and inter-annual variations of vegetation dynamics in seasonally dry tropical forests.

    Science.gov (United States)

    Xu, Xiangtao; Medvigy, David; Powers, Jennifer S; Becknell, Justin M; Guan, Kaiyu

    2016-10-01

    We assessed whether diversity in plant hydraulic traits can explain the observed diversity in plant responses to water stress in seasonally dry tropical forests (SDTFs). The Ecosystem Demography model 2 (ED2) was updated with a trait-driven mechanistic plant hydraulic module, as well as novel drought-phenology and plant water stress schemes. Four plant functional types were parameterized on the basis of meta-analysis of plant hydraulic traits. Simulations from both the original and the updated ED2 were evaluated against 5 yr of field data from a Costa Rican SDTF site and remote-sensing data over Central America. The updated model generated realistic plant hydraulic dynamics, such as leaf water potential and stem sap flow. Compared with the original ED2, predictions from our novel trait-driven model matched better with observed growth, phenology and their variations among functional groups. Most notably, the original ED2 produced unrealistically small leaf area index (LAI) and underestimated cumulative leaf litter. Both of these biases were corrected by the updated model. The updated model was also better able to simulate spatial patterns of LAI dynamics in Central America. Plant hydraulic traits are intercorrelated in SDTFs. Mechanistic incorporation of plant hydraulic traits is necessary for the simulation of spatiotemporal patterns of vegetation dynamics in SDTFs in vegetation models. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  15. Seasonal and diurnal variations in methane and carbon dioxide in the Kathmandu Valley in the foothills of the central Himalayas

    Science.gov (United States)

    Singh Mahata, Khadak; Panday, Arnico Kumar; Rupakheti, Maheswar; Singh, Ashish; Naja, Manish; Lawrence, Mark G.

    2017-10-01

    .3) ppm in the winter season. The maximum seasonal mean mixing ratio of CH4 in winter was only 0.057 ppm or 2.6 % higher than the seasonal minimum during the pre-monsoon period, while CO2 was 12.8 ppm or 3.1 % higher during the pre-monsoon period (seasonal maximum) than during the monsoon (seasonal minimum). On the other hand, the CO mixing ratio at Bode was 191 % higher during the winter than during the monsoon season. The enhancement in CO2 mixing ratios during the pre-monsoon season is associated with additional CO2 emissions from forest fires and agro-residue burning in northern South Asia in addition to local emissions in the Kathmandu Valley. Published CO/CO2 ratios of different emission sources in Nepal and India were compared with the observed CO/CO2 ratios in this study. This comparison suggested that the major sources in the Kathmandu Valley were residential cooking and vehicle exhaust in all seasons except winter. In winter, brick kiln emissions were a major source. Simultaneous measurements in Bode and Chanban (15 July-3 October 2015) revealed that the mixing ratios of CO2, CH4, and CO were 3.8, 12, and 64 % higher in Bode than Chanban. The Kathmandu Valley thus has significant emissions from local sources, which can also be attributed to its bowl-shaped geography that is conducive to pollution build-up. At Bode, all three gas species (CO2, CH4, and CO) showed strong diurnal patterns in their mixing ratios with a pronounced morning peak (ca. 08:00), a dip in the afternoon, and a gradual increase again through the night until the next morning. CH4 and CO at Chanban, however, did not show any noticeable diurnal variations. These measurements provide the first insights into the diurnal and seasonal variation in key greenhouse gases and air pollutants and their local and regional sources, which is important information for atmospheric research in the region.

  16. Seasonal and diurnal variations in methane and carbon dioxide in the Kathmandu Valley in the foothills of the central Himalayas

    Directory of Open Access Journals (Sweden)

    K. S. Mahata

    2017-10-01

    , 417.3 (±23.1 ppm in the post-monsoon, and 421.9 (±20.3 ppm in the winter season. The maximum seasonal mean mixing ratio of CH4 in winter was only 0.057 ppm or 2.6 % higher than the seasonal minimum during the pre-monsoon period, while CO2 was 12.8 ppm or 3.1 % higher during the pre-monsoon period (seasonal maximum than during the monsoon (seasonal minimum. On the other hand, the CO mixing ratio at Bode was 191 % higher during the winter than during the monsoon season. The enhancement in CO2 mixing ratios during the pre-monsoon season is associated with additional CO2 emissions from forest fires and agro-residue burning in northern South Asia in addition to local emissions in the Kathmandu Valley. Published CO∕CO2 ratios of different emission sources in Nepal and India were compared with the observed CO∕CO2 ratios in this study. This comparison suggested that the major sources in the Kathmandu Valley were residential cooking and vehicle exhaust in all seasons except winter. In winter, brick kiln emissions were a major source. Simultaneous measurements in Bode and Chanban (15 July–3 October 2015 revealed that the mixing ratios of CO2, CH4, and CO were 3.8, 12, and 64 % higher in Bode than Chanban. The Kathmandu Valley thus has significant emissions from local sources, which can also be attributed to its bowl-shaped geography that is conducive to pollution build-up. At Bode, all three gas species (CO2, CH4, and CO showed strong diurnal patterns in their mixing ratios with a pronounced morning peak (ca. 08:00, a dip in the afternoon, and a gradual increase again through the night until the next morning. CH4 and CO at Chanban, however, did not show any noticeable diurnal variations. These measurements provide the first insights into the diurnal and seasonal variation in key greenhouse gases and air pollutants and their local and regional sources, which is important information for atmospheric research in the region.

  17. Seasonal variation in mercury and food web biomagnification in Lake Ontario, Canada

    International Nuclear Information System (INIS)

    Zhang Liang; Campbell, Linda M.; Johnson, Timothy B.

    2012-01-01

    Seasonal variation in mercury (Hg) concentrations and food web structure was assessed for eastern Lake Ontario. Hg concentrations, measured in 6 species of invertebrates and 8 species of fishes, tended to be highest in the spring and lowest in the summer for most biota. Yellow perch (Perca flavescens) exhibited significant ontogenetic shifts in diet and Hg, although such patterns were not evident for other species. Food web structure, as indicated by stable isotope values (δ 15 N, δ 13 C) was not static. Log-transformed Hg data were strongly and consistently correlated with δ 15 N values for the whole food web in each of the three seasons (slopes, 0.17–0.24) and across the entire year (slope, 0.2). While significantly different between seasons, the regression slope values are still consistent with published global Hg biomagnification rates. Our results indicate that the assessment of Hg trends in Great Lakes must take into account seasonal patterns and time of sampling. - Graphical abstract: Total mercury concentrations and trophic level (δ 15 N) regressions for organisms from the littoral Lake Ontario food web of Waupoos in 2009. Filled circles represent invertebrates while open circles represent fish. Dashed lines represents the regression between δ 15 N and THg of “whole” food web (log-Hg-δ 15 N regression equations in the upper left hand corner in each plot), and solid lines represents the regression between δ 15 N and THg of “fish-only” food web (log-Hg-δ 15 N regression equations in the lower right hand corner of each plot). Note that the y-axis is untransformed Hg concentrations plotted along a logarithmic scale, while the equations are based on log-transformed Hg values. Highlights: ► Most fish in littoral Lake Ontario had higher Hg concentrations in spring and lower Hg in summer. ► Log Hg consistently biomagnified throughout the food web in each season and for the year. ► Biomagnification rates (e.g., log Hg-δ 15 N slopes) vary

  18. Longitudinal, seasonal and solar cycle variation in lunar tide influence on the equatorial electrojet

    Directory of Open Access Journals (Sweden)

    E. Yizengaw

    2017-04-01

    Full Text Available It has been well documented that the lunar tidal waves can modulate the ionospheric electrodynamics and create a visible influence on the equatorial electrojet (EEJ. The lunar tide influence gets intensified around noon, primarily during new and full Moon periods. However, the longitudinal, seasonal and solar cycle variability in the lunar tide influence on ionospheric current systems is not well understood yet. In order to investigate this, 17 years (1998–2014 of extensive magnetometer observations at four longitudinal sectors (western American, western and eastern African, and Asian have been analyzed. All observations performed during magnetically active periods (Kp>3 have been excluded for this study to eliminate storm contributions to the geomagnetic field variation at the geomagnetic equator. This study's quantitative analysis revealed significant longitudinal, seasonal and solar cycle dependence of the lunar tide influence on the equatorial electrojet.

  19. Longitudinal, seasonal and solar cycle variation in lunar tide influence on the equatorial electrojet

    Energy Technology Data Exchange (ETDEWEB)

    Yizengaw, Endawoke [Boston College, Chestnut Hill, MA (United States). Inst. for Scientific Research; Carter, Brett A. [RMIT Univ., Melbourne, VIC (Australia). SPACE Research Centre

    2017-07-01

    It has been well documented that the lunar tidal waves can modulate the ionospheric electrodynamics and create a visible influence on the equatorial electrojet (EEJ). The lunar tide influence gets intensified around noon, primarily during new and full Moon periods. However, the longitudinal, seasonal and solar cycle variability in the lunar tide influence on ionospheric current systems is not well understood yet. In order to investigate this, 17 years (1998-2014) of extensive magnetometer observations at four longitudinal sectors (western American, western and eastern African, and Asian) have been analyzed. All observations performed during magnetically active periods (K{sub p}>3) have been excluded for this study to eliminate storm contributions to the geomagnetic field variation at the geomagnetic equator. This study's quantitative analysis revealed significant longitudinal, seasonal and solar cycle dependence of the lunar tide influence on the equatorial electrojet.

  20. Seasonal variations of 222Rn concentrations in the air of a tunnel located in Nagano City

    International Nuclear Information System (INIS)

    Muramatsu, H.; Tashiro, Y.; Hasegawa, N.; Misawa, C.; Minami, M.

    2000-01-01

    The survey of 222 Rn concentrations in the air of tunnels constructed during World War II at Nagano City has been performed using a solid-state nuclear track detector technique. Concentrations of several thousands Bq m -3 were observed at inner most areas of the tunnel. A seasonal variation was clearly observed; in summer, several times higher concentrations than in winter were observed, which may be due to a stack effect induced by the temperature difference between the tunnel air and the outside air in each season. The concentrations of radon in the tunnel air decrease exponentially towards the openings of the tunnel, which indicates that the radon concentration in the tunnel is basically governed by diffusion and mixing of radon gas with air. (author)

  1. Longitudinal, seasonal and solar cycle variation in lunar tide influence on the equatorial electrojet

    International Nuclear Information System (INIS)

    Yizengaw, Endawoke; Carter, Brett A.

    2017-01-01

    It has been well documented that the lunar tidal waves can modulate the ionospheric electrodynamics and create a visible influence on the equatorial electrojet (EEJ). The lunar tide influence gets intensified around noon, primarily during new and full Moon periods. However, the longitudinal, seasonal and solar cycle variability in the lunar tide influence on ionospheric current systems is not well understood yet. In order to investigate this, 17 years (1998-2014) of extensive magnetometer observations at four longitudinal sectors (western American, western and eastern African, and Asian) have been analyzed. All observations performed during magnetically active periods (K p >3) have been excluded for this study to eliminate storm contributions to the geomagnetic field variation at the geomagnetic equator. This study's quantitative analysis revealed significant longitudinal, seasonal and solar cycle dependence of the lunar tide influence on the equatorial electrojet.

  2. THE EVALUATION OF FREQUENCY AND SEASONAL VARIATIONS OF ACID PEPTIC DISEASE: A SEVEN YEARS STUDY

    Directory of Open Access Journals (Sweden)

    Syed Iftikhar Haider

    2016-06-01

    Full Text Available Acid peptic disease (APD is a worldwide health problem. It includes a variety of inflammatory and ulcerative lesions involving esophagus, stomach and duodenum. The disease condition may persist with multiple symptoms, one of them being dyspepsia. The object of the present study was to determine the frequency and seasonal variations of APD in patients presenting with dyspeptic symptoms. This observational study was carried out at the endoscopy unit in Baqai Medical University from December 2003 to December 2010, over a period of seven years. The evolution of APD frequency remained equivocal throughout the study period. However, a decline was noted in the frequency of peptic ulcer disease (PUD especially for gastric and duodenal ulcer cases but a rise during autumn and winter seasons was also noted in duodenal ulcer cases.

  3. Seasonal Variation of Eutrophication in Some Lakes of Danube Delta Biosphere Reserve.

    Science.gov (United States)

    Török, Liliana; Török, Zsolt; Carstea, Elfrida M; Savastru, Dan

    2017-01-01

      To understand the trophic state of lakes, this study aims to determine the dynamics of phytoplankton assemblages and the main factors that influence their seasonal variation. Sampling campaigns were carried out in three lakes from the Danube Delta Biosphere Reserve. Spectral analysis of specific phytoplankton pigments was applied as a diagnostic marker to establish the distribution and composition of phytoplankton taxonomic groups. Fluorescence spectroscopy was used to quantify changes in dissolved organic matter (DOM). The relative contribution of the main phytoplankton groups to the total phytoplankton biomass and the trend of development during succession of the seasons showed that cyanobacteria could raise potential ecological or human health problems. Moreover, fluorescence spectroscopy revealed that Cryptophyta and cyanobacteria were the main contributors to the protein-like components of DOM. It was concluded that fluorescence could be used to provide a qualitative evaluation of the eutrophication degree in Danube Delta lakes.

  4. Distribution of artificial sweeteners in dust and soil in China and their seasonal variations in the environment of Tianjin.

    Science.gov (United States)

    Gan, Zhiwei; Sun, Hongwen; Yao, Yiming; Zhao, Yangyang; Li, Yan; Zhang, Yanwei; Hu, Hongwei; Wang, Ruonan

    2014-08-01

    A nationwide investigation on the occurrence of artificial sweeteners (ASs) was conducted by collecting 98 paired outdoor dust and soil samples from mainland China. The ASs were widely detected in Chinese atmospheric dry deposition and soil samples, at concentrations up to 6450 and 1280 ng/g, respectively. To give a picture on AS distribution and source in the whole environment, the concentrations and seasonal variations of ASs in Tianjin were studied, including atmosphere, soil, and water samples. The AS levels were significantly higher in Haihe river at TJW (a sampling site in central city) in winter, while no obviously seasonal trends were obtained at BYL (close to a AS factory) and the site at a wastewater treatment plant. Saccharin, cyclamate, and acesulfame were the dominant ASs in both gas and particulate phase, with concentrations varying from 0.02 to 1940 pg/m(3). Generally, gas phase concentrations of the ASs were relatively higher in summer, while opposite results were acquired for particulate phase. Wet and dry deposition fluxes were calculated based on the measured AS levels. The results indicated that both wet and dry deposition could efficiently remove ASs in the atmosphere and act as important pollutant sources for the ASs in surface environment. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Spatial Variation in Seasonal Water Poverty Index for Laos: An Application of Geographically Weighted Principal Component Analysis

    OpenAIRE

    Kallio, Marko; Guillaume, Joseph; Kummu, Matti; Virrantaus, Kirsi-Kanerva

    2017-01-01

    Water poverty, defined as insufficient water of adequate quality to cover basic needs, is an issue that may manifest itself in multiple ways. Extreme seasonal variation in water availability, such as in Laos, located in Monsoon Asia, results in large differences in water poverty conditions between dry and wet seasons. In this study, seasonal Water Poverty Indices (WPI) are developed for 8215 villages in Laos. WPI is a multidimensional composite index integrating five dimensions of water: reso...

  6. Meridional distribution and seasonal variation of stable oxygen isotope ratio of precipitation in the Southern Ocean

    Directory of Open Access Journals (Sweden)

    Kayo Nakamura

    2010-07-01

    Full Text Available The stable oxygen isotope ratio(δ^O in precipitation is known to have important meridional and seasonal variations, but there are almost no measurements of δ^O in precipitation over polar oceans. The present research took advantage of 4 opportunities for in situ observations in summer and winter at high latitudes in the Southern Ocean. In addition, we analyzed samples of precipitation at Syowa Station in 2008 to obtain year-round data. Based on these data, we consider the meridional and seasonal variations of δ^O in precipitation over the Southern Ocean. In general, δ^O decreases with increasing latitude, and is lower in winter than in summer. The latitude gradient is stronger in winter. At 60°S, δ^O is -5.4‰ and -11.3‰ in summer and winter, respectively, while the corresponding figures at 66°S are -10.5‰ and -20.8‰. These results will help us understand the mechanisms of the salinity distribution and its variation in the Antarctic Ocean.

  7. Simultaneous observation of seasonal variations of beryllium-7 and typical POPs in near-surface atmospheric aerosols in Guangzhou, China

    Science.gov (United States)

    Pan, Jing; Yang, Yong-Liang; Zhang, Gan; Shi, Jing-Lei; Zhu, Xiao-Hua; Li, Yong; Yu, Han-Qing

    2011-07-01

    Near-surface atmospheric aerosol samples were collected at the sampling frequency of 2-3 d per week for one year from August 2006 to August 2007 at a low latitude station in Tianhe District, Guangzhou, Guangdong Province of southern China. The samples were analyzed for cosmogenic nuclide 7Be and persistent organic pollutants, i.e. organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs). The annual average 7Be concentration was 2.59 mBq m -3, with the maximum occurred in May (8.45 mBq m -3) and minimum in late August and early September (0.07 mBq m -3). Winter and spring were the seasons in which the 7Be concentrations were high while summer and autumn were the lower 7Be seasons. Spring peaks in 7Be in the near-surface atmospheric aerosols may have associated with the "spring leak maximum" episode. The annual average ∑OCPs concentration was 345.6 pg m -3, ∑ 33PCBs 317.6 pg m -3, and ∑ 31PBDEs 609.0 pg m -3. The variation trends in the time-series of 7Be, OCPs, PCBs, and PBDEs in near-surface atmospheric aerosol showed both common features and differences. Significant correlations ( R2 = 0.957 and 0.811. respectively, p = 0.01) were observed between the monthly average 7Be concentrations and those of ∑PCBs and ∑PBDEs in summer, autumn, and early winter. The difference between the seasonal variation features of OCPs and PCBs (and PBDEs) could be attributed to the different source functions and physical-chemical properties which could control the behaviors of these compounds in air-aerosol partitions as well as atmospheric transport.

  8. Influence of seasonal variations in sea level on the salinity regime of a coastal groundwater-fed wetland.

    Science.gov (United States)

    Wood, Cameron; Harrington, Glenn A

    2015-01-01

    Seasonal variations in sea level are often neglected in studies of coastal aquifers; however, they may have important controls on processes such as submarine groundwater discharge, sea water intrusion, and groundwater discharge to coastal springs and wetlands. We investigated seasonal variations in salinity in a groundwater-fed coastal wetland (the RAMSAR listed Piccaninnie Ponds in South Australia) and found that salinity peaked during winter, coincident with seasonal sea level peaks. Closer examination of salinity variations revealed a relationship between changes in sea level and changes in salinity, indicating that sea level-driven movement of the fresh water-sea water interface influences the salinity of discharging groundwater in the wetland. Moreover, the seasonal control of sea level on wetland salinity seems to override the influence of seasonal recharge. A two-dimensional variable density model helped validate this conceptual model of coastal groundwater discharge by showing that fluctuations in groundwater salinity in a coastal aquifer can be driven by a seasonal coastal boundary condition in spite of seasonal recharge/discharge dynamics. Because seasonal variations in sea level and coastal wetlands are ubiquitous throughout the world, these findings have important implications for monitoring and management of coastal groundwater-dependent ecosystems. © 2014, National Ground Water Association.

  9. Variations in soil carbon sequestration and their determinants along a precipitation gradient in seasonally dry tropical forest ecosystems.

    Science.gov (United States)

    Campo, Julio; Merino, Agustín

    2016-05-01

    The effect of precipitation regime on the C cycle of tropical forests is poorly understood, despite the existence of models that suggest a drier climate may substantially alter the source-sink function of these ecosystems. Along a precipitation regime gradient containing 12 mature seasonally dry tropical forests growing under otherwise similar conditions (similar annual temperature, rainfall seasonality, and geological substrate), we analyzed the influence of variation in annual precipitation (1240 to 642 mm) and duration of seasonal drought on soil C. We investigated litterfall, decomposition in the forest floor, and C storage in the mineral soil, and analyzed the dependence of these processes and pools on precipitation. Litterfall decreased slightly - about 10% - from stands with 1240 mm yr(-1) to those with 642 mm yr(-1), while the decomposition decreased by 56%. Reduced precipitation strongly affected C storage and basal respiration in the mineral soil. Higher soil C storage at the drier sites was also related to the higher chemical recalcitrance of litter (fine roots and forest floor) and the presence of charcoal across sites, suggesting an important indirect influence of climate on C sequestration. Basal respiration was controlled by the amount of recalcitrant organic matter in the mineral soil. We conclude that in these forest ecosystems, the long-term consequences of decreased precipitation would be an increase in organic layer and mineral soil C storage, mainly due to lower decomposition and higher chemical recalcitrance of organic matter, resulting from changes in litter composition and, likely also, wildfire patterns. This could turn these seasonally dry tropical forests into significant soil C sinks under the predicted longer drought periods if primary productivity is maintained. © 2016 John Wiley & Sons Ltd.

  10. [Heavy metals pollution and analysis of seasonal variation runoff in Xi'an].

    Science.gov (United States)

    Yuan, Hong-Lin; Li, Xing-Yu; Wang, Xiao-Chang

    2014-11-01

    In order to explore heavy metals pollution situation,changes in characteristics, the correlation between each heavy mental and pollution source analysis of Xi'an various regions in different season in one year. This study collected several samples of Xi'an rainfall typical urban trunk roads throughout the year in 2013 and used inductively coupled plasma mass spectrometry (ICP-MS) to determine the level of Fe, Mn, Pb, Zn, Al, Cd of the samples, then, analyzed the seasonal change of heavy mental. Studies have shown that: the heavy metal of Xi'an road runoff pollutes seriously, the concentration of Fe over three times of the national standard and maintain the higher levels throughout the year, meanwhile the concentration with the intensity of human activities increases. The concentration of Mn and Zn in one year show a trends: winter > autumn > summer> spring. Pb concentration increases with the increase in traffic volume, while showing: winter > spring > summer > autumn. Factor analysis shows: Fe and Al was affected by the same sources-natural sources; Zn, Cd affected by anthropogenic sources of large; Mn, Pb affected by the larger traffic sources.

  11. Seasonal variations in PM composition from Beijing, China drive liver oxidative stress

    Science.gov (United States)

    Pardo, M.; Rudich, Y.

    2017-12-01

    Air pollution can cause oxidative stress, inflammation and adverse health effects, but the underlying biological mechanisms are not completely understood. In order to understand how seasonal and chemical variations drive health impacts, we investigated the oxidative stress and inflammation in mice exposed to extracts (water and DCM) from urban PM collected in Beijing (China). Higher levels of pollution components were detected in the heating season (HS, winter) than in the non-heating season (NHS, summer). Higher concentrations of PM were measured in the heating season, mostly from coal and wood burning used for domestic heating. This was accompanied by increased levels of polyaromatic hydrocarbons (PAHs) in the DCM extracts. An increased inflammatory response was detected in the lung and liver with DCM extracts compared to the water extracts, and mostly in the winter aerosol. Reduced antioxidant response was observed in the lung, whereas it was activated in the liver. Gene expression of the Nrf2 transcription factor (A master regulator of stress response that controls the basal oxidative capacity and induces the expression of antioxidant response) and its related genes were induced. In the liver, higher levels of lipid peroxidation adducts were measured, correlated with histologic analysis that revealed morphologic features of damage/proliferation in the liver, indicating oxidative and toxic damage. Altogether, our study suggests that the acute effects of PM can vary by the season with the largest effect observed in winter than summer in Beijing, and that some secondary organs may be susceptible for exposure damage. This suggests that the liver is a potential organ to be influenced from PM especially by PAHs

  12. Ecophysiological response to seasonal variations in water availability in the arborescent, endemic plant Vellozia gigantea.

    Science.gov (United States)

    Morales, Melanie; Garcia, Queila S; Munné-Bosch, Sergi

    2015-03-01

    The physiological response of plants growing in their natural habitat is strongly determined by seasonal variations in environmental conditions and the interaction of abiotic and biotic stresses. Here, leaf water and nutrient contents, changes in cellular redox state and endogenous levels of stress-related phytohormones (abscisic acid (ABA), salicylic acid and jasmonates) were examined during the rainy and dry season in Vellozia gigantea, an endemic species growing at high elevations in the rupestrian fields of the Espinhaço Range in Brazil. Enhanced stomatal closure and increased ABA levels during the dry season were associated with an efficient control of leaf water content. Moreover, reductions in 12-oxo-phytodienoic acid (OPDA) levels during the dry season were observed, while levels of other jasmonates, such as jasmonic acid and jasmonoyl-isoleucine, were not affected. Changes in ABA and OPDA levels correlated with endogenous concentrations of iron and silicon, hydrogen peroxide, and vitamin E, thus indicating complex interactions between water and nutrient contents, changes in cellular redox state and endogenous hormone concentrations. Results also suggested crosstalk between activation of mechanisms for drought stress tolerance (as mediated by ABA) and biotic stress resistance (mediated by jasmonates), in which vitamin E levels may serve as a control point. It is concluded that, aside from a tight ABA-associated regulation of stomatal closure during the dry season, crosstalk between activation of abiotic and biotic defences, and nutrient accumulation in leaves may be important modulators of plant stress responses in plants growing in their natural habitat. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. Seasonal Variations in Surface Metabolite Composition of Fucus vesiculosus and Fucus serratus from the Baltic Sea.

    Directory of Open Access Journals (Sweden)

    Esther Rickert

    Full Text Available Perennial macroalgae within the genus Fucus are known to exude metabolites through their outer thallus surface. Some of these metabolites have pro- and/or antifouling properties. Seasonal fluctuations of natural fouling pressure and chemical fouling control strength against micro- and macrofoulers have previously been observed in Fucus, suggesting that control strength varies with threat. To date, a study on the seasonal composition of surface associated metabolites, responsible for much of the fouling control, has not been done. We sampled individuals of the two co-occurring species F. vesiculosus and F. serratus at monthly intervals (six per species and month during a one-year field study. We analysed the chemical composition of surface associated metabolites of both Fucus species by means of gas chromatography-mass spectrometry (GC-MS to describe temporal patterns in chemical surface composition. Additionally, we correlated abiotic and biotic parameters recorded monthly within the sampled habitat with the variation in the chemical surface landscape of Fucus. Our study revealed that the chemical surface composition of both Fucus species exhibits substantial seasonal differences between spring/summer and autumn/winter months. Light and temperature explained most of the seasonal variability in surface metabolite composition of both Fucus species. A strong summerly up-regulation of eighteen saccharides and two hydroxy acids in F. vesiculosus as well as of four fatty acids and two saccharides in F. serratus was observed. We discuss how these up-regulated molecules may have a complex effect on associated microfoulers, both promoting or decreasing fouling depending on metabolite and bacterial identity. These seasonal shifts in the surface metabolome seem to exert a compound control of density and composition of the Fucus associated biofilm.

  14. Seasonal variations in TSH serum levels in athyreotic patients under L-thyroxine replacement monotherapy.

    Science.gov (United States)

    Gullo, Damiano; Latina, Adele; Frasca, Francesco; Squatrito, Sebastiano; Belfiore, Antonino; Vigneri, Riccardo

    2017-08-01

    Whether serum TSH undergoes seasonal fluctuations in euthyroid and hypothyroid residents of temperate climates is controversial. Monthly TSH and thyroid hormone levels were cross-sectionally analysed in a large cohort of euthyroid subjects (n=11 806) and L-thyroxine (L-T4)-treated athyreotic patients (n=3 934). Moreover, in a small group (n=119) of athyreotic patients treated with an unchanged dosage of L-T4 monotherapy, hormones were measured both in the coldest and in the hottest seasons of the same year (longitudinal study). No seasonal hormone change was observed in the euthyroid subjects except for a small FT3 increase in winter (+2.9%, P<.001). In contrast, the L-T4-treated athyreotic patients had significantly higher serum TSH values in the cold season when the FT4 values were significantly lower. The differences were more notable in the longitudinal series (TSH, 0.80 vs. 0.20 mU/L and FT4, 16.3 vs. 17.8 pmol/L in December-March vs. June-September, respectively). In these patients also serum FT3 values significantly decreased in winter (in the longitudinal series, 3.80 in winter vs 4.07 pmol/L in summer). Regression analysis showed that in athyreotic subjects, a greater FT4 change is required to obtain a TSH change similar to that of euthyroid controls and that this effect is more pronounced in the summer. Athyreotic patients undergoing L-T4 monotherapy have abnormal seasonal variations in TSH. These changes are secondary to the FT4 and FT3 serum decreases in winter, which occur in spite of the constant treatment. The underlying mechanisms are unclear, but in some cases, these changes may be clinically relevant. © 2017 John Wiley & Sons Ltd.

  15. Geospatial approach for assessment of biophysical vulnerability to agricultural drought and its intra-seasonal variations.

    Science.gov (United States)

    Sehgal, Vinay Kumar; Dhakar, Rajkumar

    2016-03-01

    The study presents a methodology to assess and map agricultural drought vulnerability during main kharif crop season at local scale and compare its intra-seasonal variations. A conceptual model of vulnerability based on variables of exposure, sensitivity, and adaptive capacity was adopted, and spatial datasets of key biophysical factors contributing to vulnerability were generated using remote sensing and GIS for Rajasthan State of India. Hazard exposure was based on frequency and intensity of gridded standardized precipitation index (SPI). Agricultural sensitivity was based on soil water holding capacity as well as on frequency and intensity of normalized difference vegetation index (NDVI)-derived trend adjusted vegetation condition index (VCITadj). Percent irrigated area was used as a measure of adaptive capacity. Agricultural drought vulnerability was derived separately for early, mid, late, and whole kharif seasons by composting rating of factors using linear weighting scheme and pairwise comparison of multi-criteria evaluation. The regions showing very low to extreme rating of hazard exposure, drought sensitivity, and agricultural vulnerability were identified at all four time scales. The results indicate that high to extreme vulnerability occurs in more than 50% of net sown area in the state and such areas mostly occur in western, central, and southern parts. The higher vulnerability is on account of non-irrigated croplands, moderate to low water holding capacity of sandy soils, resulting in higher sensitivity, and located in regions with high probability of rainfall deficiency. The mid and late season vulnerability has been found to be much higher than that during early and whole season. Significant correlation of vulnerability rating with food grain productivity, drought recurrence period, crop area damaged in year 2009 and socioeconomic indicator of human development index (HDI) proves the general soundness of methodology. Replication of this methodology

  16. Seasonal variations in the characteristics of superficial sediments in a macrotidal estuary (the Seine inlet, France)

    Science.gov (United States)

    Lesourd, S.; Lesueur, P.; Brun-Cottan, J. C.; Garnaud, S.; Poupinet, N.

    2003-09-01

    Seasonal variations in the sedimentary regime in the mouth of the Seine river, a macrotidal estuary, are described for a 3-year period. The aim of this study is to characterize and to understand the main governing mechanisms, using data from more than a thousand of superficial sediment grab samples or box cores gathered throughout the study period. Analyses of lithofacies and rheological properties were carried out. The distribution of sediments is governed by seasonal meteorological variations. The surface covered by mud reaches a maximum (40% of the total mouth area) during winter. After the winter, the soft mud deposits are progressively redistributed throughout the whole estuary area and onto the shelf. During the lowest freshwater flow at the end of summer, the fine-grained sediments cover less than 20% of the river mouth area. These seasonal variations mainly depend on the river discharge intensity, but are also linked to wave activity. In the study area, the amount of fine-grained deposits after high river flow periods depends on (1) volume of mud erodable within the estuary, (2) the duration of the flood tidal influx, and (3) the duration preceding the particular annual high river flow. During the last decades, filling of the estuary upstream from Honfleur has led to a downstream shift of the fine-grained sediment deposition area; following this, the present-day mud deposition area is in the open part of the estuary, in the subtidal shallow area. Subsequently, fresh mud deposits undergo intense hydrodynamical and meteorological effects, and are partly reworked by waves and tidal currents effects. In this study, it is shown that the behaviour of suspended matter and of superficial sediments is strongly influenced by short but intense events including high river flows and gales.

  17. Seasonal variations of radon and the radiation exposure levels in Nerja cave, Spain

    International Nuclear Information System (INIS)

    Duenas, C.; Fernandez, M.C.; Canete, S.; Perez, M.; Gordo, E.

    2011-01-01

    222 Rn concentrations in the air in Nerja cave (Spain) (3 o 52'35''W 36 o 43'50''N) were measured by continuous monitoring using Alpha-Guard, Genitron instrument equipment. The 222 Rn measurements were carried out for a complete annual cycle in the different halls: Vestibule hall from July 2003 to June 2004, Ballet hall from July 2004 to June 2005 and Mirador hall from July 2005 to June 2006. Starting from the entrance of the cave we successively find the Vestibule hall, the Ballet hall and the Mirador hall. The range of 222 Rn levels were of 8-627 Bq m -3 for the Vestibule hall, 28-575 Bq m -3 for the Ballet hall and 38-578 Bq m -3 for the Mirador. The aim of this study was to detect seasonal variation patterns of 222 Rn concentrations. The seasonal variations of 222 Rn concentrations are discussed in relation to various meteorological factors measured inside and outside the cave. The radiation exposure levels for workers and tourists with different equilibrium factors have been evaluated. The radiation exposure levels for workers and tourists only represent a low percentage of the exposure guides for the general population. - Highlights: → The aim of the study was to detect seasonal variation of 222 Rn concentrations. → 222 Rn concentrations in the air-cave were measured by continuous monitoring. → The 222 Rn measurements were carried out in the different halls of the cave. → The radiation exposure levels for workers and tourists have been evaluated.

  18. Study of Seasonal Variation in Groundwater Quality of Sagar City (India by Principal Component Analysis

    Directory of Open Access Journals (Sweden)

    Hemant Pathak

    2011-01-01

    Full Text Available Groundwater is one of the major resources of the drinking water in Sagar city (India.. In this study 15 sampling station were selected for the investigations on 14 chemical parameters. The work was carried out during different months of the pre-monsoon, monsoon and post-monsoon seasons in June 2009 to June 2010. The multivariate statistics such as principal component and cluster analysis were applied to the datasets to investigate seasonal variations in groundwater quality. Principal axis factoring has been used to observe the mode of association of parameters and their interrelationships, for evaluating water quality. Average value of BOD, COD, ammonia and iron was high during entire study period. Elevated values of BOD and ammonia in monsoon, slightly more value of BOD in post-monsoon, BOD, ammonia and iron in pre-monsoon period reflected contribution on temporal effect on groundwater. Results of principal component analysis evinced that all the parameters equally and significantly contribute to groundwater quality variations. Factor 1 and factor 2 analysis revealed the DO value deteriorate due to organic load (BOD/Ammonia in different seasons. Hierarchical cluster analysis grouped 15 stations into four clusters in monsoon, five clusters in post-monsoon and five clusters in pre-monsoon with similar water quality features. Clustered group at monsoon, post-monsoon and pre-monsoon consisted one station exhibiting significant spatial variation in physicochemical composition. The anthropogenic nitrogenous species, as fallout from modernization activities. The study indicated that the groundwater sufficiently well oxygenated and nutrient-rich in study places.

  19. Seasonal variations in the biochemical composition of some common seaweed species from the coast of Abu Qir Bay, Alexandria, Egypt

    OpenAIRE

    Khairy, Hanan M.; El-Shafay, Shimaa M.

    2013-01-01

    Variations in protein, carbohydrate, lipid, ash, moisture, fatty acid and aminoacid contents of the seaweeds Ulva lactuca Linnaeus (Chlorophyta),Jania rubens (Linnaeus) J.V. Lamouroux and Pterocladia capillacea (S.G. Gmelin) Bornet(Rhodophyta) were studied seasonally from spring to autumn 2010. The seaweeds were collected from a rocky site near Boughaz El-Maadya on the coast of Abu Qir Bay east of Alexandria, Egypt. Remarkable seasonal variations were recorded in the levels of the studied pa...

  20. [Seasonal variation of Tamarix ramosissima and Populus euphratica water potentials in southern fringe of Taklamakan Desert].

    Science.gov (United States)

    Zeng, Fanjiang; Zhang, Ximing; Li, Xiangyi; Foetzki, Andrea; Runge, Michael

    2005-08-01

    The measurement of the seasonal and diurnal variations of Tamarix ramosissima and Populus euphratica water potentials in the southern fringe of Taklamakan Desert indicated that there was no apparent water stress for the two species during their growth period, with little change of predawn water potential and some extent decrease of midday water potential. Irrigation once or thinning had no significant effects on the water status of the plants, while groundwater appeared to be a prerequisite for the survival and growth of these species. It is very important to ensure a stable groundwater table for the restoration of Tamarix ramosissima and Populus euphratica in this area.

  1. Seasonal variations of bisphenol A in the Danube River by the municipality of Novi Sad, Serbia

    Directory of Open Access Journals (Sweden)

    Milanović Maja

    2016-01-01

    Full Text Available Seasonal variations of bisphenol A (BPA were investigated in the Danube along the Novi Sad bank, Serbia using solid-phase extraction followed by gas chromatographic mass spectrometric method. The obtained results confirmed the presence of BPA above the limit of quantification (6 ng/L in 22 out of 32 water samples at all eight sampling sites. Тhe BPA concentration varied from 1 for autumn, spring and summer. The high potential risk which is attributed to the elevated summer concentrations is probably the result of the increased human activates and weather conditions. [Projekat Ministarstva nauke Republike Srbije, br. III46009

  2. Using stable isotopes to determine seasonal variations in water uptake of summer maize under different fertilization treatments

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Ying, E-mail: maying@igsnrr.ac.cn [Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 100101 Beijing (China); State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 210008 Nanjing (China); Song, Xianfang [Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 100101 Beijing (China)

    2016-04-15

    Fertilization and water both affect root water uptake in the nutrient and water cycle of the Soil-Plant-Atmosphere-Continuum (SPAC). In this study, dual stable isotopes (D and {sup 18}O) were used to determine seasonal variations in water uptake patterns of summer maize under different fertilization treatments in Beijing, China during 2013–2014. The contributions of soil water at different depths to water uptake were quantified by the MixSIAR Bayesian mixing model. Water uptake was mainly sourced from soil water in the 0–20 cm depth at the seeding (67.7%), jointing (60.5%), tasseling (47.5%), dough (41.4%), and harvest (43.9%) stages, and the 20–50 cm depth at the milk stage (32.8%). Different levels of fertilization application led to considerable differences in the proportional contribution of soil water at 0–20 cm (6.0–58.5%) and 20–50 cm (6.1–26.3%). There was little difference of contributions in the deep layers (50–200 cm) among treatments in 2013, whereas differences were observed in 50–90 cm at the milk stage and 50–200 cm at the dough stage during 2014. The main water uptake depth was concentrated in the upper soil layers (0–50 cm) during the wet season (2013), whereas a seasonal drought in 2014 promoted the contribution of soil water in deep layers. The contribution of soil water was significantly and positively correlated with the proportions of root length (r = 0.753, p < 0.01). The changes of soil water distribution were consistent with the seasonal variation in water uptake patterns. The present study identified water sources for summer maize under varying fertilization treatments and provided scientific implications for fertilization and irrigation management. - Highlights: • Dual stable isotopes and MixSIAR were coupled to quantify water uptake of maize. • Maize mainly used soil water in 20–50 cm at milk stage and 0–20 cm at other stages. • Fertilization treatments led to distinct water uptake pattern at 0–50 cm

  3. Using stable isotopes to determine seasonal variations in water uptake of summer maize under different fertilization treatments

    International Nuclear Information System (INIS)

    Ma, Ying; Song, Xianfang

    2016-01-01

    Fertilization and water both affect root water uptake in the nutrient and water cycle of the Soil-Plant-Atmosphere-Continuum (SPAC). In this study, dual stable isotopes (D and "1"8O) were used to determine seasonal variations in water uptake patterns of summer maize under different fertilization treatments in Beijing, China during 2013–2014. The contributions of soil water at different depths to water uptake were quantified by the MixSIAR Bayesian mixing model. Water uptake was mainly sourced from soil water in the 0–20 cm depth at the seeding (67.7%), jointing (60.5%), tasseling (47.5%), dough (41.4%), and harvest (43.9%) stages, and the 20–50 cm depth at the milk stage (32.8%). Different levels of fertilization application led to considerable differences in the proportional contribution of soil water at 0–20 cm (6.0–58.5%) and 20–50 cm (6.1–26.3%). There was little difference of contributions in the deep layers (50–200 cm) among treatments in 2013, whereas differences were observed in 50–90 cm at the milk stage and 50–200 cm at the dough stage during 2014. The main water uptake depth was concentrated in the upper soil layers (0–50 cm) during the wet season (2013), whereas a seasonal drought in 2014 promoted the contribution of soil water in deep layers. The contribution of soil water was significantly and positively correlated with the proportions of root length (r = 0.753, p < 0.01). The changes of soil water distribution were consistent with the seasonal variation in water uptake patterns. The present study identified water sources for summer maize under varying fertilization treatments and provided scientific implications for fertilization and irrigation management. - Highlights: • Dual stable isotopes and MixSIAR were coupled to quantify water uptake of maize. • Maize mainly used soil water in 20–50 cm at milk stage and 0–20 cm at other stages. • Fertilization treatments led to distinct water uptake pattern at 0–50 cm depth

  4. Seasonal variations of melatonin in ram seminal plasma are correlated to those of testosterone and antioxidant enzymes

    Directory of Open Access Journals (Sweden)

    Muiño-Blanco Teresa

    2010-06-01

    Full Text Available Abstract Background Some breeds of sheep are highly seasonal in terms of reproductive capability, and these changes are regulated by photoperiod and melatonin secretion. These changes affect the reproductive performance of rams, impairing semen quality and modifying hormonal profiles. Also, the antioxidant defence systems seem to be modulated by melatonin secretion, and shows seasonal variations. The aim of this study was to investigate the presence of melatonin and testosterone in ram seminal plasma and their variations between the breeding and non-breeding seasons. In addition, we analyzed the possible correlations between these hormones and the antioxidant enzyme defence system activity. Methods Seminal plasma from nine Rasa Aragonesa rams were collected for one year, and their levels of melatonin, testosterone, superoxide dismutase (SOD, glutathione reductase (GRD, glutathione peroxidase (GPX and catalase (CAT were measured. Results All samples presented measurable quantities of hormones and antioxidant enzymes. Both hormones showed monthly variations, with a decrease after the winter solstice and a rise after the summer solstice that reached the maximum levels in October-November, and a marked seasonal variation (P Conclusions These results show the presence of melatonin and testosterone in ram seminal plasma, and that both hormones have seasonal variations, and support the idea that seasonal variations of fertility in the ram involve interplay between melatonin and the antioxidant defence system.

  5. Influence of landscape features on variation of δ2H and δ18O in seasonal mountain snowpack

    Science.gov (United States)

    Kipnis, E. L.; Chapple, W.; Frank, J. M.; Traver, E.; Ewers, B. E.; Williams, D. G.

    2014-12-01

    Streamflow contributions from snowpack remain difficult to predict in snow dominated headwater catchments in the Rocky Mountains. There remains considerable uncertainty in how environmental change in mountain watersheds alter seasonal snowpack accumulation and development and how these relationships translate from gaged to ungaged catchments. Stable isotope analysis is a valuable tool for determining the contribution and changes of different source inputs to catchment water budgets. Stable isotope values in snowpack integrate source inputs and processes such as water vapor exchange, selective redistribution, and melt. For better understanding of how these physical processes vary at local and catchment scales, snowpack density, depth, snow water equivalence (SWE), δ2H and δ18O were examined at peak snowpack in spring 2013 and 2014 and at monthly time steps throughout the winter of 2013-2014. Distributed data and sample collection occurred between 2400 and 3300 m elevation across two pine beetle and spruce beetle impacted forest stands with variable canopy cover in the Libby Creek and Nash Fork Little Laramie River basins, Medicine Bow Range, Wyoming. Peak snowpack within these watersheds was 10% below historic average in 2013 and 50% above average in 2014 (NRCS Snotel data). Even with these contrasting peak snowpack patterns, elevation described less than 40% of the spatial variation of snow water equivalents (SWE) across the watersheds for both seasons. Hydrogen and oxygen isotope ratio values of snowpack sampled monthly in 2014 revealed early season separation from the local meteoric water line, suggesting some kinetic isotope effects. However, isotope ratio values at peak snowpack in 2013 reflected no such signal at any sampling location. The influence of landscape position and canopy cover will be modeled to detect and scale spatial and temporal changes in SWE and stable isotope composition of snowpack. Such an approach will provide increased understanding of

  6. Seasonal and Non-Seasonal Variations of Jupiter's Atmosphere from Observations of Thermal Emission, 1994-2011

    Science.gov (United States)

    Orton, G.; Fletcher, L.; Yanamandra-Fisher, P.; Greathouse, T.; Fisher, B.; Greco, J.; Wakefield, L.; Snead, E.; Boydstun, K.; Simon-Miller, A.; hide

    2012-01-01

    We analyzed mid-infrared images of Jupiter's thermal emission, covering approx.1.5 Jovian years, acquired in discrete filters between 7.8 and 24.5 microns. The behavior of stratospheric (approx.10-mbar) and tropospheric (approx.100-400 mbar) temperatures is generally consistent with predictions of seasonal variability, with differences between 100-mbar temperatures +/-50-60deg from the equator on the order of +/-2. Removing this effect, there appear to be long-term quasi-periodic variability of tropospheric temperatures, whose amplitude, phase and period depend on latitude. The behavior of temperatures in the Equatorial Zone (EZ) suggests a approx.4-6-year period with amplitude of about +/-1-1.5 K in temperature. At mid-latitudes, the periodicity is more distinct with amplitudes around +/-1.5-2.5 K and 4-8 year periods. The 4.2-year variation of stratospheric temperatures known as the quasiquadrennial oscillation or "QQO" (Leovy et al. 1991, Nature 354, 380) continued during this period. There were no variations of zonal mean temperatures associated with any of the "global upheaval" events that have produced dramatic changes of jupiter's visible appearance and cloud cover, although there are colder discrete regions associated with updrafts, e.g. the early stages of the re-darkening ("revival") of the South Equatorial Belt (SEB) in late 2010. On the other hand increases in the visible albedos ("fades") of belts are accompanied by increases in the thickness of a 700-mbar cloud layer (most likely NH3 ice) and clouds at higher pressures, together with the mixing ratio of NH3 gas near 400 mbar (above its condensation level). These quantities decrease during re-darkening ("revival") episodes, during which we note discrete features that are exceptions to the general correlation between dark albedos and minimal cloudiness. In contrast to all these changes, the meridional distribution of the 240-mbar para-H2 fraction appears to be invariant in time.

  7. Severity of infection and seasonal variation of non-typhoid Salmonelle occurence in humans

    DEFF Research Database (Denmark)

    Gradel, K.O.; Dethlefsen, Claus; Schønheyder, H.C.

    2007-01-01

    Non-typhoid Salmonella infections may present as severe gastroenteritis necessitatinghospitalization and some patients become septic with bacteraemia. We hypothesized that theseasonal variation of non-typhoid Salmonella occurrence in humans diminishes with increasedseverity of infection. We...... examined the seasonal variation of non-typhoid Salmonella infections inthree patient groups with differing severity of infection: outpatients treated for gastroenteritis(n=1490); in-patients treated for gastroenteritis (n=492); and in-patients treated for bacteraemia(n=113). The study was population......-based and included all non-typhoid Salmonella patients ina Danish county from 1994 to 2003. A periodic regression model was used to compute thepeak-to-trough ratio for the three patient groups. The peak-to-trough ratios were 4·3 [95%confidence interval (CI) 3·6–5.0] for outpatients with gastroenteritis, 3·2 (95% CI...

  8. Seasonal variation of the underground cosmic muon flux observed at Daya Bay

    Science.gov (United States)

    An, F. P.; Balantekin, A. B.; Band, H. R.; Bishai, M.; Blyth, S.; Cao, D.; Cao, G. F.; Cao, J.; Chan, Y. L.; Chang, J. F.; Chang, Y.; Chen, H. S.; Chen, Q. Y.; Chen, S. M.; Chen, Y. X.; Chen, Y.; Cheng, J.; Cheng, Z. K.; Cherwinka, J. J.; Chu, M. C.; Chukanov, A.; Cummings, J. P.; Ding, Y. Y.; Diwan, M. V.; Dolgareva, M.; Dove, J.; Dwyer, D. A.; Edwards, W. R.; Gill, R.; Gonchar, M.; Gong, G. H.; Gong, H.; Grassi, M.; Gu, W. Q.; Guo, L.; Guo, X. H.; Guo, Y. H.; Guo, Z.; Hackenburg, R. W.; Hans, S.; He, M.; Heeger, K. M.; Heng, Y. K.; Higuera, A.; Hsiung, Y. B.; Hu, B. Z.; Hu, T.; Huang, E. C.; Huang, H. X.; Huang, X. T.; Huber, P.; Huo, W.; Hussain, G.; Jaffe, D. E.; Jen, K. L.; Jetter, S.; Ji, X. P.; Ji, X. L.; Jiao, J. B.; Johnson, R. A.; Jones, D.; Kang, L.; Kettell, S. H.; Khan, A.; Kohn, S.; Kramer, M.; Kwan, K. K.; Kwok, M. W.; Kwok, T.; Langford, T. J.; Lau, K.; Lebanowski, L.; Lee, J.; Lee, J. H. C.; Lei, R. T.; Leitner, R.; Li, C.; Li, D. J.; Li, F.; Li, G. S.; Li, Q. J.; Li, S.; Li, S. C.; Li, W. D.; Li, X. N.; Li, X. Q.; Li, Y. F.; Li, Z. B.; Liang, H.; Lin, C. J.; Lin, G. L.; Lin, S.; Lin, S. K.; Lin, Y.-C.; Ling, J. J.; Link, J. M.; Littenberg, L.; Littlejohn, B. R.; Liu, J. L.; Liu, J. C.; Loh, C. W.; Lu, C.; Lu, H. Q.; Lu, J. S.; Luk, K. B.; Ma, X. Y.; Ma, X. B.; Ma, Y. Q.; Malyshkin, Y.; Martinez Caicedo, D. A.; McDonald, K. T.; McKeown, R. D.; Mitchell, I.; Nakajima, Y.; Napolitano, J.; Naumov, D.; Naumova, E.; Ngai, H. Y.; Ochoa-Ricoux, J. P.; Olshevskiy, A.; Pan, H.-R.; Park, J.; Patton, S.; Pec, V.; Peng, J. C.; Pinsky, L.; Pun, C. S. J.; Qi, F. Z.; Qi, M.; Qian, X.; Qiu, R. M.; Raper, N.; Ren, J.; Rosero, R.; Roskovec, B.; Ruan, X. C.; Sebastiani, C.; Steiner, H.; Sun, J. L.; Tang, W.; Taychenachev, D.; Treskov, K.; Tsang, K. V.; Tull, C. E.; Viaux, N.; Viren, B.; Vorobel, V.; Wang, C. H.; Wang, M.; Wang, N. Y.; Wang, R. G.; Wang, W.; Wang, X.; Wang, Y. F.; Wang, Z.; Wang, Z.; Wang, Z. M.; Wei, H. Y.; Wen, L. J.; Whisnant, K.; White, C. G.; Whitehead, L.; Wise, T.; Wong, H. L. H.; Wong, S. C. F.; Worcester, E.; Wu, C.-H.; Wu, Q.; Wu, W. J.; Xia, D. M.; Xia, J. K.; Xing, Z. Z.; Xu, J. L.; Xu, Y.; Xue, T.; Yang, C. G.; Yang, H.; Yang, L.; Yang, M. S.; Yang, M. T.; Yang, Y. Z.; Ye, M.; Ye, Z.; Yeh, M.; Young, B. L.; Yu, Z. Y.; Zeng, S.; Zhan, L.; Zhang, C.; Zhang, C. C.; Zhang, H. H.; Zhang, J. W.; Zhang, Q. M.; Zhang, X. T.; Zhang, Y. M.; Zhang, Y. X.; Zhang, Y. M.; Zhang, Z. J.; Zhang, Z. Y.; Zhang, Z. P.; Zhao, J.; Zhou, L.; Zhuang, H. L.; Zou, J. H.

    2018-01-01

    The Daya Bay Experiment consists of eight identically designed detectors located in three underground experimental halls named as EH1, EH2, EH3, with 250, 265 and 860 meters of water equivalent vertical overburden, respectively. Cosmic muon events have been recorded over a two-year period. The underground muon rate is observed to be positively correlated with the effective atmospheric temperature and to follow a seasonal modulation pattern. The correlation coefficient α, describing how a variation in the muon rate relates to a variation in the effective atmospheric temperature, is found to be αEH1 = 0.362±0.031, αEH2 = 0.433±0.038 and αEH3 = 0.641±0.057 for each experimental hall.

  9. Seasonal variation of Brazilian red propolis: Antibacterial activity, synergistic effect and phytochemical screening.

    Science.gov (United States)

    Regueira, M S; Tintino, Saulo Relison; da Silva, Ana Raquel Pereira; Costa, Maria do Socorro; Boligon, Aline Augusti; Matias, Edinardo F F; de Queiroz Balbino, Valdir; Menezes, Irwin R A; Melo Coutinho, Henrique Douglas

    2017-09-01

    The aim of this study was to investigate the effect of the dry and rainy season on the antibacterial activity and chemical composition of the Brazilian red propolis. The samples were collected in rainy (RP-PER) and dry (RP-PED) seasons and analyzed by HPLC-DAD. The extracts were tested alone and in association with antibiotics against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. The HPLC analysis identified luteolin and quercetin as the main compounds. Seasonal variation was observed according to concentrations of the compounds. The MIC values against E. coli ranged from 128 μg/mL to 512 μg/mL (EC 06 and EC ATCC). The red propolis showed MIC values of 512 μg/mL against both strains of P. aeruginosa used in our study (PA03 and PA24) and against strains of Gram-positive bacteria S. aureus the MICs ranged from 64 μg/mL to ≥1024 μg/mL (SA10). A synergistic effect was observed when we combined the RP-PED with gentamicin against all the strains tested. When we combined the RP-PED with Imipenem, we only observed synergistic effect against P. aeruginosa. According to our synergistic activity results, the utilization of red propolis collected in the drier periods can be used as an adjuvant against multiresistant bacterial infections. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Seasonal variations in soil water in two woodland savannas of central Brazil with different fire history.

    Science.gov (United States)

    Quesada, Carlos Alberto; Hodnett, Martin G; Breyer, Lacê M; Santos, Alexandre J B; Andrade, Sérgio; Miranda, Heloisa S; Miranda, Antonio Carlos; Lloyd, Jon

    2008-03-01

    Changes in soil water content were determined in two cerrado (sensu stricto) areas with contrasting fire history and woody vegetation density. The study was undertaken near Brasília, Brazil, from 1999 to 2001. Soil water content was measured with a neutron probe in three access tubes per site to a depth of 4.7 m. One site has been protected from fire for more than 30 years and, as a consequence, has a high density of woody plants. The other site had been frequently burned, and has a high herbaceous vegetation density and less woody vegetation. Soil water uptake patterns were strongly seasonal, and despite similarities in hydrological processes, the protected area systematically used more water than the burned area. Three temporarily contiguous patterns of water absorption were differentiated, characterized by variation in the soil depth from which water was extracted. In the early dry season, vegetation used water from throughout the soil profile but with a slight preference for water in the upper soil layers. Toward the peak of the dry season, vegetation had used most or all available water from the surface to a depth of 1.7 m, but continued to extract water from greater depths. Following the first rains, all water used was from the recently wetted upper soil layers only. Evaporation rates were a linear function of soil water availability, indicating a strong coupling of atmospheric water demand and the physiological response of the vegetation.

  11. Spatial and seasonal variations of fish assemblages in mangrove creek systems in Zanzibar (Tanzania)

    Science.gov (United States)

    Mwandya, Augustine W.; Gullström, Martin; Andersson, Mathias H.; Öhman, Marcus C.; Mgaya, Yunus D.; Bryceson, Ian

    2010-11-01

    Spatial and seasonal variations of fish assemblage composition were studied in three non-estuarine mangrove creeks of Zanzibar (Tanzania). Fish were collected monthly for one year at three sites (lower, intermediate and upper reaches) in each creek using a seine net (each haul covering 170 m 2). Density, species number and diversity of fish were all higher at sites with dense cover of macrophytes (seagrass and macroalgae) than over unvegetated sandy sites. In general, fish assemblages mainly comprised juveniles of a few abundant taxa, e.g. Mugil cephalus, Mugilidae spp. and Leiognathus equulus at sites with mud substratum and Gerres oyena, Lethrinus harak and Sillago sihama at sites dominated by macrophytes. Multivariate analyses revealed significant separations in fish assemblage composition within the two creeks where the bottom substratum differed among sites. Overall, season seemed to have little effect on density, species number, diversity index ( H') and assemblage structure of fish. Water condition variables were also relatively stable across the season, although a short-term fluctuation primarily induced by decreased salinity, occurred during the heavy rains in April and May. Fish assemblage structure was not significantly affected by any of the abiotic factors tested. However, significant regressions were found between the other fish variables and environmental variables, but since these associations were mostly species-specific and generally inconsistent, we suggest that the overall distribution patterns of fish were mainly an effect of particular substrate preferences of fish species rather than contemporary water conditions.

  12. Understanding the Response of Photosynthetic Metabolism in Tropical Forests to Seasonal Climate Variations. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Dye, Dennis [U.S. Geological Survey, Menlo Park, CA (United States); Ivanov, Valeriy [Univ. of Michigan, Ann Arbor, MI (United States); Saleska, Scott [Univ. of Arizona, Tucson, AZ (United States); Huete, Alfredo [Univ. of Arizona, Tucson, AZ (United States); Univ. of Technology, Sydney NSW (Australia)

    2017-03-31

    This U.S-Brazil collaboration for GOAmazon has investigated a deceptively simple question: what controls the response of photosynthesis in Amazon tropical forests to seasonal variations in climate? In the past this question has been difficult to answer with modern earth system process models. We hypothesized that observed dry season increases in photosynthetic capacity are controlled by the phenology of leaf flush and litter fall, from which the seasonal pattern of LAI emerges. Our results confirm this hypothesis (Wu et al., 2016). Synthesis of data collected throughout the 3-year project period continues through December 31, 2017 under no-cost extensions granted to the project teams at University of Michigan and University of Arizona (Award 2). The USGS component (Award 1) ceased on the final date of the project performance period, December 31, 2016. This report summarizes the overall activities and achievements of the project, and constitutes the final project report for the USGS component. The University of Michigan will submit a separate final report that includes additional results and deliverables achieved during the period of their and the University of Arizona’s no-cost extension, which will end on December 31, 2017.

  13. Seasonal and altitudinal variation in roe deer (Capreolus pygargus tianschanicus diet on Jeju Island, South Korea

    Directory of Open Access Journals (Sweden)

    Pradeep Adhikari

    2016-12-01

    Full Text Available In order to understand the feeding ecology and dietary differences of roe deer (Capreolus pygargus tianschanicus in different seasons and altitudes, this study was carried out at three altitudinal sites (Songdang 250–270 m above sea level (ASL, Aradong 330–370 m ASL, Mt. Hallasan 1100 m ASL on Jeju Island, South Korea. Altogether, 205 plants taxa of six categories of foods (forbs-climbers, graminoids, trees, shrubs, conifers, and ferns were identified using morphological and molecular analyses. The highest number of dietary plants was found in summer (93 taxa and at Aradong (124 taxa and lowest at Songdang (71 taxa and in winter (51 taxa. Food categories were significantly different among the seasons (F = 15.646, p < 0.05 and altitudinal sites (F = 3.941, p < 0.05. This study revealed that dietary selectivity of roe deer shifted with seasonal and altitudinal variations and preferred to the nutritive and low fibers food.

  14. Seasonal variations of trace elements in precipitation at the largest city in Tibet, Lhasa

    Science.gov (United States)

    Guo, Junming; Kang, Shichang; Huang, Jie; Zhang, Qianggong; Tripathee, Lekhendra; Sillanpää, Mika

    2015-02-01

    Precipitation samples were collected from March 2010 to August 2012 at an urban site in Lhasa, the capital and largest city of Tibet. The volume weighted mean (VWM) concentrations of 17 trace elements in precipitation were higher during the non-monsoon season than in the monsoon season, but inverse seasonal variations occurred for wet deposition fluxes of most of the trace elements. Concentrations for most of trace elements were negatively correlated with precipitation amount, indicating that below-cloud scavenging of trace elements was an important mechanism contributing to wet deposition of these elements. The elements Al, Sc, V, Cr, Mn, Fe, Mn, Ni, and U displayed low crustal enrichment factors (EFs), whereas Co, Cu, Zn, As, Cd Sn, Pb, and Bi showed high EF values in precipitation, suggesting that anthropogenic activities might be important contributors of these elements at Lhasa. However, this present work indicates a much lower anthropogenic emission at Lhasa than in seriously polluted regions. Our study will not only provide insights for assessing the current status of the atmospheric environment in Lhasa but also enhance our understanding for updating the baseline for environmental protection over the Tibetan Plateau.

  15. Seasonal Variation of Provitamin D2 and Vitamin D2 in Perennial Ryegrass (Lolium perenne L.)

    DEFF Research Database (Denmark)

    Jäpelt, Rie Bak; Didion, Thomas; Smedsgaard, Jørn

    2011-01-01

    Ergosterol (provitamin D(2)) is converted to vitamin D(2) in grass by exposure to UV light. Six varieties of perennial ryegrass (Lolium perenne L.) were harvested four times during the season, and the contents of vitamin D(2) and ergosterol were analyzed by a sensitive and selective liquid...... chromatography tandem mass spectrometry method. Weather factors were recorded, and a principal component analysis was performed to study which factors were important for the formation of vitamin D(2). The results suggest that a combination of weather factors is involved and that the contents of ergosterol...... and vitamin D(2) change more than a factor of 10 during the season. These results demonstrate that grass potentially can be a significant source of vitamin D for grazing animals and animals fed on silage and hay....

  16. Seasonal Climate Variation and Caribou Availability: Modeling Sequential Movement Using Satellite-Relocation Data

    Directory of Open Access Journals (Sweden)

    Craig Nicolson

    2013-06-01

    Full Text Available Livelihood systems that depend on mobile resources must constantly adapt to change. For people living in permanent settlements, environmental changes that affect the distribution of a migratory species may reduce the availability of a primary food source, with the potential to destabilize the regional social-ecological system. Food security for Arctic indigenous peoples harvesting barren ground caribou (Rangifer tarandus granti depends on movement patterns of migratory herds. Quantitative assessments of physical, ecological, and social effects on caribou distribution have proven difficult because of the significant interannual variability in seasonal caribou movement patterns. We developed and evaluated a modeling approach for simulating the distribution of a migratory herd throughout its annual cycle over a multiyear period. Beginning with spatial and temporal scales developed in previous studies of the Porcupine Caribou Herd of Canada and Alaska, we used satellite collar locations to compute and analyze season-by-season probabilities of movement of animals between habitat zones under two alternative weather conditions for each season. We then built a set of transition matrices from these movement probabilities, and simulated the sequence of movements across the landscape as a Markov process driven by externally imposed seasonal weather states. Statistical tests showed that the predicted distributions of caribou were consistent with observed distributions, and significantly correlated with subsistence harvest levels for three user communities. Our approach could be applied to other caribou herds and could be adapted for simulating the distribution of other ungulates and species with similarly large interannual variability in the use of their range.

  17. The Effect of Seasonal Weather Variation on the Dynamics of the Plague Disease

    Directory of Open Access Journals (Sweden)

    Rigobert C. Ngeleja

    2017-01-01

    Full Text Available Plague is a historic disease which is also known to be the most devastating disease that ever occurred in human history, caused by gram-negative bacteria known as Yersinia pestis. The disease is mostly affected by variations of weather conditions as it disturbs the normal behavior of main plague disease transmission agents, namely, human beings, rodents, fleas, and pathogens, in the environment. This in turn changes the way they interact with each other and ultimately leads to a periodic transmission of plague disease. In this paper, we formulate a periodic epidemic model system by incorporating seasonal transmission rate in order to study the effect of seasonal weather variation on the dynamics of plague disease. We compute the basic reproduction number of a proposed model. We then use numerical simulation to illustrate the effect of different weather dependent parameters on the basic reproduction number. We are able to deduce that infection rate, progression rates from primary forms of plague disease to more severe forms of plague disease, and the infectious flea abundance affect, to a large extent, the number of bubonic, septicemic, and pneumonic plague infective agents. We recommend that it is more reasonable to consider these factors that have been shown to have a significant effect on RT for effective control strategies.

  18. Chemical composition and seasonal variation of the volatile oils from Trembleya phlogiformis leaves

    Directory of Open Access Journals (Sweden)

    Sarah R. Fernandes

    Full Text Available ABSTRACT Trembleya phlogiformis DC., Melastomataceae, is a shrub whose leaves are used as a dye for dyeing wool and cotton. The present article aimed to carry out the morphological description of the species, to study the chemical composition of volatile oils from the leaves and flowers and the seasonal variability from the leaves during a year. Macroscopic characterization was carried out with the naked eye and with a stereoscopic microscope. Volatile oils were isolated by hydrodistillation in Clevenger apparatus and analyzed by gas chromatography/mass spectrometry. The major components of the volatile oil of T. phlogiformis flowers were: n-heneicosane (33.5%, phytol (12.3%, n-tricosane (8.4% and linoleic acid (6.1%. It was verified the existence of a large chemical variability of the volatile oils from the leaves of T. phlogiformis over the months, with the majority compound (oleic alcohol, ranging from 5.7 to 26.8% present in all samples. A combination of Cluster Analysis and Principal Component Analysis showed the existence of three main clusters, probably related to the seasons. The results suggested that the volatile oils of T. phlogiformis leaves possess high chemical variability, probably related to variation associated with rainfall and the variation in the behavior of specimens throughout the year. This research provides insights for future studies on the volatile oils obtained from the T. phlogiformis leaves and flowers, mainly related to biological markers of applications monitored in the leaves and flowers of this species.

  19. Seasonal and Interannual Variation in Energy Balance in the Semiarid Grassland Area of China

    Directory of Open Access Journals (Sweden)

    Qun’ou Jiang

    2015-01-01

    Full Text Available Near surface energy budget changes have been proved to be induced by the land cover conversion through changing the surface physical properties, which can further impact the regional climate change. This study applies the DLS model to simulate the land cover under the business as usual (BAU scenario and then analyses the seasonal and interannual variation of energy balance in the semiarid grassland area of China based on the simulated land cover with the Weather Research and Forecasting (WRF model. The results indicate that the grassland will show a growing trend under the BAU scenario. Downward long wave radiation and downward short wave radiation will all have small-scale increase with time going by, while the surface net radiation will decrease from 2030 to 2050. However, there is obvious seasonal variation. Summer has the highest downward long wave radiation and downward short wave radiation, followed by spring and autumn. The lowest are in winter. As for the net surface radiation, there is obvious decrease in southeast of study area due to returning cropland to grassland. Those research conclusions can offer valuable information for the land use planning and relieving the effects of land cover change on climate change at the semiarid grassland area.

  20. Seasonal variations in terrestrial gamma radiation along river Ganges and implications to public health risk

    International Nuclear Information System (INIS)

    Sharma, P.; Meher, P.K.; Mishra, K.P.

    2016-01-01

    Measurement of exposure to terrestrial gamma radiation dose and determination of associated health hazard at river bank is of major importance due to the increasing tourism, bathing festivals and mythological beliefs. Present study was focused on measurement of absorbed dose rates as function of seasonal variation at designated locations along Ganges river in India. Portable dosimeter (plastic scintillation counter) was used for the measurement of absorbed dose rates. Subsequently, annual effective dose (AED) and excess lifetime cancer risk (ELCR) were calculated by the standard procedure. Results showed absorbed dose rates for Pre-monsoon ranged from 89.7 ± 4.03 to 115.0 ± 7.81 nSv/h with an average of 105.54 nSv/h. Post-monsoon measurements yielded values from 81.0 ± 7.00 to 105.6 ± 5.75 nSv/h with an average value of 90.8 nSv/h. Calculated average AED for Pre-monsoon period was found to be 0.13 mSv/y. Whereas, 0.11 mSv/y was the AED for the post-monsoon period. Furthermore, the calculated average ELCR values for pre-monsoon and post-monsoon were found to be 0.488 × 10 -3 and 0.418 × 10 -3 , respectively. This study reports significant seasonal variations in the terrestrial gamma radiation doses along the long stretch of Ganges river. (author)

  1. Natural variation in germination responses of Arabidopsis to seasonal cues and their associated physiological mechanisms

    Science.gov (United States)

    Barua, Deepak; Butler, Colleen; Tisdale, Tracy E.; Donohue, Kathleen

    2012-01-01

    Background and Aims Despite the intense interest in phenological adaptation to environmental change, the fundamental character of natural variation in germination is almost entirely unknown. Specifically, it is not known whether different genotypes within a species are germination specialists to particular conditions, nor is it known what physiological mechanisms of germination regulation vary in natural populations and how they are associated with responses to particular environmental factors. Methods We used a set of recombinant inbred genotypes of Arabidopsis thaliana, in which linkage disequilibrium has been disrupted over seven generations, to test for genetic variation and covariation in germination responses to distinct environmental factors. We then examined physiological mechanisms associated with those responses, including seed-coat permeability and sensitivity to the phytohormones gibberellic acid (GA) and abscisic acid (ABA). Key Results Genetic variation for germination was environment-dependent, but no evidence for specialization of germination to different conditions was found. Hormonal sensitivities also exhibited significant genetic variation, but seed-coat properties did not. GA sensitivity was associated with germination responses to multiple environmental factors, but seed-coat permeability and ABA sensitivity were associated with specific germination responses, suggesting that an evolutionary change in GA sensitivity could affect germination in multiple environments, but that of ABA sensitivity may affect germination under more restricted conditions. Conclusions The physiological mechanisms of germination responses to specific environmental factors therefore can influence the ability to adapt to diverse seasonal environments encountered during colonization of new habitats or with future predicted climate change. PMID:22012958

  2. Water chemistry in Kuji river. Its spatial and seasonal variations in major ions and organic substances

    Energy Technology Data Exchange (ETDEWEB)

    Niina, Toshiaki; Matsunaga, Takeshi; Amano, Hikaru [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1996-02-01

    As a basic research with a aim to clarify the migration behavior of radionuclides in rivers, the characteristics of dissolved ions and organic substances in river water, which characteristics may affect the behavior, was investigated. The investigation was carried out for the Kuji river in the northern Kanto district (Japan) comprising four sampling campaigns in 1994 for 10 locations from the upstream to the downstream. Concentrations of major ions, iron and manganese species and organic substances were analyzed in laboratory. Values of temperature of the water, pH, conductivity, dissolved oxygen were measured in the field. This investigation was conducted mainly under low water flow conditions of the river, while a limited number of campaigns were under high flow conditions due to precipitation events. The concentrations of major inorganic ions increased steadily toward the down-stream, resulting in approximately two times increase for the traveling distance of 100 km. They showed a seasonal variation that they were highest in the spring and lowest in the autumn when there were most concentrated precipitation events in a year. The constituents were mainly Na{sup +}, Ca{sup 2+}, SO{sub 4}{sup 2-} and HCO{sub 3}{sup -}, and were similar for every sampling locations and seasons. Concentrations of dissolved organic substances (carbon compounds) were lowest in the upstream and increased about twice in the downstream as well as major inorganic ions. Their level was 1-3 mg/l, which can be ranked as relatively lower in general values for fresh water environments. They were highest in the spring (average over the locations: 2.2 mg/l) and lowest in the autumn (1.3 mg/l) and also in the winter (1.3 mg/l). These results will be useful as a basic understanding of spatial and seasonal variations of river water chemistry, especially related to the organic substances which can bind with radionuclides to make a mobile complex. (author).

  3. Physiological and Molecular Response of Ostrich to the Seasonal and Diurnal Variations in Egyptian conditions

    International Nuclear Information System (INIS)

    Khalil, M.H.; Khalifa, H.H; Elaroussi, M.A.; Elsayed, M.A.; Basuony, H.A.

    2013-01-01

    Twelve immature ostrich›s birds, 7 months old were used to evaluate the effect of ambient temperature variation and diurnal effect on response changes of some physiological and chemical parameters. All birds were reared out doors and exposed to daily ambient temperatures fluctuations during summer and winter. Blood samples were taken twice, one in the morning at 7 Am and once in the afternoon at 3 Pm during a representative 7 hot days of June (summer) (40±2ºC) and the 7 cold days of January (winter) (18±2ºC). Serum calcium, inorganic phosphorus, sodium, potassium, uric acid concentrations and aldosterone level were determined. The amount of total body water (TBW) and serum heat shock proteins (HSP) were estimated. Serum calcium, phosphorus, sodium and potassium concentrations in ostrich were significantly decreased, while uric acid concentration and aldosterone hormone level were significantly increased in summer as compared in winter during both at morning and at afternoon periods. Concerning the diurnal variation, serum calcium, phosphorus, sodium and potassium concentrations and aldosterone hormone level in ostrich were significantly increased, while uric acid concentration was significantly decreased at morning as compared at afternoon during both summer and winter seasons. TBW was significantly higher in summer season by 15.04% than winter season. It is concluded from the present study that heat or cold stress has a negative effect on most of the parameters studied and we recommend must be supplement diet with some nutrients like vitamins C, and E, sodium bicarbonate or yeast to overcome the negative effect and to better perform under such conditions

  4. Water chemistry in Kuji river. Its spatial and seasonal variations in major ions and organic substances

    International Nuclear Information System (INIS)

    Niina, Toshiaki; Matsunaga, Takeshi; Amano, Hikaru

    1996-02-01

    As a basic research with a aim to clarify the migration behavior of radionuclides in rivers, the characteristics of dissolved ions and organic substances in river water, which characteristics may affect the behavior, was investigated. The investigation was carried out for the Kuji river in the northern Kanto district (Japan) comprising four sampling campaigns in 1994 for 10 locations from the upstream to the downstream. Concentrations of major ions, iron and manganese species and organic substances were analyzed in laboratory. Values of temperature of the water, pH, conductivity, dissolved oxygen were measured in the field. This investigation was conducted mainly under low water flow conditions of the river, while a limited number of campaigns were under high flow conditions due to precipitation events. The concentrations of major inorganic ions increased steadily toward the down-stream, resulting in approximately two times increase for the traveling distance of 100 km. They showed a seasonal variation that they were highest in the spring and lowest in the autumn when there were most concentrated precipitation events in a year. The constituents were mainly Na + , Ca 2+ , SO 4 2- and HCO 3 - , and were similar for every sampling locations and seasons. Concentrations of dissolved organic substances (carbon compounds) were lowest in the upstream and increased about twice in the downstream as well as major inorganic ions. Their level was 1-3 mg/l, which can be ranked as relatively lower in general values for fresh water environments. They were highest in the spring (average over the locations: 2.2 mg/l) and lowest in the autumn (1.3 mg/l) and also in the winter (1.3 mg/l). These results will be useful as a basic understanding of spatial and seasonal variations of river water chemistry, especially related to the organic substances which can bind with radionuclides to make a mobile complex. (author)

  5. Seasonal variation and trends in stroke hospitalizations and mortality in a South American community hospital.

    Science.gov (United States)

    Díaz, Alejandro; Gerschcovich, Eliana Roldan; Díaz, Adriana A; Antía, Fabiana; Gonorazky, Sergio

    2013-10-01

    Numerous studies have reported the presence of temporal variations in biological processes. Seasonal variation (SV) in stroke has been widely studied, but little data have been published on this phenomenon in the Southern Hemisphere, and there have been no studies reported from Argentina. The goals of the present study were to describe the SV of admissions and deaths for stroke and examine trends in stroke morbidity and mortality over a 3-year period in a community hospital in Argentina. Hospital discharge reports from the electronic database of vital statistics between 1999 and 2001 were examined retrospectively. Patients who had a main discharge diagnosis of stroke (ischemic or hemorrhagic) or cerebrovascular accident (International Classification of Diseases, Ninth Revision codes 431, 432, 434, and 436) were selected. The study sample included 1382 hospitalizations by stroke (3.5% of all admissions). In-hospital mortality demonstrated a winter peak (25.5% vs 17% in summer; P = .001). The crude seasonal stroke attack rate (ischemic and hemorrhagic) was highest in winter (164 per 100,000 population; 95% CI, 159-169 per 100,000) and lowest in summer (124 per 100,000; 95% CI, 120-127 per 100,000; P = .008). Stroke admissions followed a seasonal pattern, with a winter-spring predominance (P = .008). Our data indicate a clear SV in stroke deaths and admissions in this region of Argentina. The existence of SV in stroke raises a different hypothesis about the rationale of HF admissions and provides information for the organization of care and resource allocation. Copyright © 2013 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  6. Prediction of seasonal climate-induced variations in global food production

    Science.gov (United States)

    Iizumi, Toshichika; Sakuma, Hirofumi; Yokozawa, Masayuki; Luo, Jing-Jia; Challinor, Andrew J.; Brown, Molly E.; Sakurai, Gen; Yamagata, Toshio

    2013-10-01

    Consumers, including the poor in many countries, are increasingly dependent on food imports and are thus exposed to variations in yields, production and export prices in the major food-producing regions of the world. National governments and commercial entities are therefore paying increased attention to the cropping forecasts of important food-exporting countries as well as to their own domestic food production. Given the increased volatility of food markets and the rising incidence of climatic extremes affecting food production, food price spikes may increase in prevalence in future years. Here we present a global assessment of the reliability of crop failure hindcasts for major crops at two lead times derived by linking ensemble seasonal climatic forecasts with statistical crop models. We found that moderate-to-marked yield loss over a substantial percentage (26-33%) of the harvested area of these crops is reliably predictable if climatic forecasts are near perfect. However, only rice and wheat production are reliably predictable at three months before the harvest using within-season hindcasts. The reliabilities of estimates varied substantially by crop--rice and wheat yields were the most predictable, followed by soybean and maize. The reasons for variation in the reliability of the estimates included the differences in crop sensitivity to the climate and the technology used by the crop-producing regions. Our findings reveal that the use of seasonal climatic forecasts to predict crop failures will be useful for monitoring global food production and will encourage the adaptation of food systems toclimatic extremes.

  7. Effect of seasonal variation on the composition and properties of raw milk destined for processing in the UK.

    Science.gov (United States)

    Chen, Biye; Lewis, Michael J; Grandison, Alistair S

    2014-09-01

    The composition and physical properties of raw milk from a commercial herd were studied over a 1 year period in order to understand how best to utilise milk for processing throughout the year. Protein and fat levels demonstrated seasonal trends, while minerals and many physical properties displayed considerable variations, which were apparently unrelated to season. However, rennet clotting time, ethanol stability and foaming ability were subject to seasonal variation. Many significant interrelationships in physico-chemical properties were found. It is clear that the milk supply may be more suited to the manufacture of different products at different times of the year or even on a day to day basis. Subsequent studies will report on variation in production and quality of products manufactured from the same milk samples described in the current study and will thus highlight potential advantages of seasonal processing of raw milk. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Seasonal variation of macromedusae (Cnidaria at North Bay, Florianópolis, southern Brazil

    Directory of Open Access Journals (Sweden)

    Miodeli Nogueira Júnior

    2010-06-01

    Full Text Available Seasonal variation of large medusae abundance and biomass was studied in the North Bay, Santa Catarina, southern Brazil (27°30'S, 48° 32'W, from February to December 2005. Collecting was conducted seasonally with the help of fishing bottom trawl in 30-minute sections (12 in summer, 18 in each of the remaining seasons in six stations, totaling 66 samples. Eight species were found: the hydrozoans Aequorea sp., Olindias sambaquiensis Müller, 1861, and Rhacostoma atlantica L. Agassiz, 1850; the cubozoans Chiropsalmus quadrumanus (Müller, 1859 and Tamoya haplonema Müller, 1859, and the scyphozoans Aurelia sp., Chrysaora lactea Eschscholtz, 1829 and Lychnorhiza lucerna Haeckel, 1880. Capture rates were low, up to 38 indiv. ha-1, and only ~47% of the samples were positive for jellyfish, comprising 206 individuals. Medusae abundance and species richness clearly changed from one season to another, but did not vary between the sites. Higher species richness (7 out of 8 and greater abundances were recorded during the fall (~60% and 72% of all medusae individuals and biomass respectively. Specific frequency of capture varied from 1.5 to 29% and C. lactea was the only species found in more than 25% of the samples. The three most common species dominated in different periods of the year: C. lactea during fall (78% of individuals and 60% of biomass, R. atlantica during winter (90% of individuals and 17% of biomass, and O. sambaquiensis in spring (78% of individuals and 40% of biomass. Only two individuals were caught during summer, one C. lactea and one R. atlantica. The results offer a general picture of the distribution of the macromedusae in the North Bay, but a continuous monitoring is desirable for a more detailed knowledge on the jellyfish dynamics in the Brazilian coastal waters.

  9. Chlorophyll fluorescence tracks seasonal variations of photosynthesis from leaf to canopy in a temperate forest.

    Science.gov (United States)

    Yang, Hualei; Yang, Xi; Zhang, Yongguang; Heskel, Mary A; Lu, Xiaoliang; Munger, J William; Sun, Shucun; Tang, Jianwu

    2017-07-01

    Accurate estimation of terrestrial gross primary productivity (GPP) remains a challenge despite its importance in the global carbon cycle. Chlorophyll fluorescence (ChlF) has been recently adopted to understand photosynthesis and its response to the environment, particularly with remote sensing data. However, it remains unclear how ChlF and photosynthesis are linked at different spatial scales across the growing season. We examined seasonal relationships between ChlF and photosynthesis at the leaf, canopy, and ecosystem scales and explored how leaf-level ChlF was linked with canopy-scale solar-induced chlorophyll fluorescence (SIF) in a temperate deciduous forest at Harvard Forest, Massachusetts, USA. Our results show that ChlF captured the seasonal variations of photosynthesis with significant linear relationships between ChlF and photosynthesis across the growing season over different spatial scales (R 2  = 0.73, 0.77, and 0.86 at leaf, canopy, and satellite scales, respectively; P chlorophyll content (R 2  = 0.65 for canopy GPP SIF and chlorophyll content; P < 0.0001), leaf area index (LAI) (R 2  = 0.35 for canopy GPP SIF and LAI; P < 0.0001), and normalized difference vegetation index (NDVI) (R 2  = 0.36 for canopy GPP SIF and NDVI; P < 0.0001). Our results suggest that ChlF can be a powerful tool to track photosynthetic rates at leaf, canopy, and ecosystem scales. © 2016 John Wiley & Sons Ltd.

  10. Seasonal Temperature Variations controlling Cave Ventilation Processes in Cueva Larga, Puerto Rico

    Science.gov (United States)

    Winter, A.; Vieten, R.; Warken, S. F.; Schrӧder-Ritzrau, A.; Miller, T. E.; Scholz, D.

    2016-12-01

    Two years of monthly monitoring result in much better understanding of ventilation processes in caves. Cueva Larga, a tropical cave in Puerto Rico is 1440 m long with a large main passage (about 116,000 m3). Cave air pCO2 in the main passage varied seasonally, between 600 ppm in winter and 1800 ppm in summer. The seasonal variability in cave pCO2 made it possible to estimate a cave air exchange time of 36±5 days and a winter ventilation rate of 3,200±800 m3/day for the main cave passage. Calculations of virtual temperature and differences between cave and surface temperature show that the seasonal temperature cycle is the main driver of the alternation between a well-ventilated winter mode and a near-stagnant summer mode. The winter mode is characterized by a positive buoyancy contrast at night leading to maximal cave ventilation, while during summer ventilation is at a minimum. Between winter and summer, a transitional mode of partial cave ventilation is observed. On shorter time scales (diurnal to weekly), cave pCO2 is also influenced by atmospheric pressure but this variation is one order of magnitude lower than the seasonal pCO2 change. The cave morphology of Cueva Larga including its large volume, tubular shape and the obstructed cave entrance geometry are important boundary conditions for the observed ventilation patterns. Our findings emphasize that cave systems with varying morphology have to be studied individually in order to correctly describe ventilation processes.

  11. Spatio-Temporal Variations and Source Apportionment of Water Pollution in Danjiangkou Reservoir Basin, Central China

    Directory of Open Access Journals (Sweden)

    Pan Chen

    2015-05-01

    Full Text Available Understanding the spatio-temporal variation and the potential source of water pollution could greatly improve our knowledge of human impacts on the environment. In this work, data of 11 water quality indices were collected during 2012–2014 at 10 monitoring sites in the mainstream and major tributaries of the Danjiangkou Reservoir Basin, Central China. The fuzzy comprehensive assessment (FCA, the cluster analysis (CA and the discriminant analysis (DA were used to assess the water pollution status and analyze its spatio-temporal variation. Ten sites were classified by the high pollution (HP region and the low pollution (LP region, while 12 months were divided into the wet season and the dry season. It was found that the HP region was mainly in the small tributaries with small drainage areas and low average annual discharges, and it was also found that most of these rivers went through urban areas with industrial and domestic sewages input into the water body. Principal component analysis/factor analysis (PCA/FA was applied to reveal potential pollution sources, whereas absolute principal component score-multiple linear regression (APCS-MLR was used to identify their contributions to each water quality variable. The study area was found as being generally affected by industrial and domestic sewage. Furthermore, the HP region was polluted by chemical industries, and the LP region was influenced by agricultural and livestock sewage.

  12. Distribution, Seasonal Variations and Ecological Risk Assessment of Polycyclic Aromatic Hydrocarbons in Foliar Dust of Nanjing, China.

    Science.gov (United States)

    Zha, Yan; Zhang, Yinlong; Ma, Zilong; Tang, Jie; Sun, Kai

    2018-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are of concern for both ecosystem and human health due to their potential teratogenic, carcinogenic, and mutagenic properties. The concentration of ∑ 16 PAHs in foliar dust ranged from 49.4 to 19,018.1 µg kg -1 , with a mean value of 7074.5 µg kg -1 . There were significant seasonal variations in the concentration of ∑ 16 PAHs, with the concentration in winter being almost twice as high as in summer. Similarly, the differences between PAH profiles in different seasons indicated that they had common sources, which were attributed to the combined effect of regional transport and local emissions. The diagnostic ratios of indicator compounds indicated that PAHs detected in foliar dust originated from a mixture of gasoline vehicle emissions, biomass, and coal combustion in Nanjing. According to the ecological risk classification of ∑ 16 PAHs, the ecological risk caused by PAHs was high since the value of RQ ∑16PAHs(MPCs) was ≥ 1 and RQ ∑16PAHs(NCs) were ≥ 800. The mean values for RQ∑ 16 PAHs (MPCs) and RQ∑ 16 PAHs (NCs) were 14.8 and 2368.9, which indicated a relatively high ecological risks of PAHs in foliar dust in Nanjing.

  13. [Distributions and seasonal variations of total dissolved inorganic arsenic in the estuaries and coastal area of eastern Hainan].

    Science.gov (United States)

    Cao, Xiu-Hong; Ren, Jing-Ling; Zhang, Gui-Ling; Zhang, Jin-E; Du, Jin-Zhou; Zhu, De-Di

    2012-03-01

    The concentrations of total dissolved inorganic arsenic (TDIAs) were measured by Hydride Generation-Atomic Fluorescence Spectrometry (HG-AFS). Two cruises were carried out in the river, estuary, coastal area and groundwater of eastern Hainan in December 2006 and August 2007. The concentrations of TDIAs in the Wanquan and Wenchang/Wenjiao rivers and their estuaries, coastal area in December 2006 were 4.0-9.4, 1.3-13.3, 13.3-17.3 nmol x L(-1), respectively. The concentrations of TDIAs in the Wanquan and Wenchang/Wenjiao rivers and their estuaries, coastal area in August 2007 were 1.6-15.5, 2.4-15.9, 10.8-17.6 nmol x L(-1), respectively. There was no significantly seasonal variation of TDIAs in the rivers and estuaries during the dry and wet seasons. Compared with other areas in the world, the concentration of TDIAs in the Eastern Hainan remained at pristine levels. TDIAs showed conservatively mixing in the both estuaries. The concentration of TDIAs of groundwater was below detection limit (BDL)-41.7 nmol x L(-1). The submarine groundwater discharge (SGD) to the coastal area was estimated in the drainage basin of Wenchang/Wenjiao river based on the average concentration of TDIAs in the groundwater and SGD water discharge, with the value of 1 153 mol x a(-1). Budget estimation indicated that the SGD discharge is one of the important sources of arsenic in the coastal area.

  14. Seasonal Differences in Climatic Controls of Vegetation Growth in the Beijing-Tianjin Sand Source Region of China.

    Science.gov (United States)

    Wang, H.

    2017-12-01

    Seasonal differences in climatic controls of vegetation growth in the Beijing-Tianjin Sand Source Region of China Bin He1 , Haiyan Wan11 State Key Laboratory of Earth Surface Processes and Resource Ecology, College of Global Change and Earth System Science, Beijing Normal University, Beijing 100875, China Corresponding author: Bin He, email addresses: hebin@bnu.edu.cnPhone:+861058806506, Address: Beijing Normal University, College of Global Change and Earth System Science, Beijing Normal University, Beijing 100875, China. Email addresses of co-authors: wanghaiyan@mail.bnu.edu.cnABSTRACTLaunched in 2000, the Beiing-Tainjin Sand Source Controlling Project (BTSSCP) is an ecological restoration project intended to prevent desertification in China. Evidence from multiple sources has confirmed increases in vegetation growth in the BTSSCP region since the initiation of the project. Precipitation and related soil moisture conditions typically are considered to be the main drivers of vegetation growth in this arid region. However, by investigating the relationships between vegetation growth and corresponding climatic factors, we identified seasonal variation in the climatic constraints of vegetation growth. In spring, vegetation growth is stimulated mainly by elevated temperature, whereas precipitation is the lead driver of summer greening. In autumn, positive effects of both temperature and precipitation on vegetation growth were observed. Furthermore, strong biosphere-atmosphere interactions were observed in this region. Spring warming promotes vegetation growth, but also reduces soil moisture. Summer greening has a strong cooling effect on land surface temperature. These results indicate that 1) precipitation-based projections of vegetation growth may be misleading; and 2) the ecological and environment consequences of ecological projects should be comprehensively evaluated. KEYWORDS: vegetation growth, climatic drivers, seasonal variation, BTSSCP

  15. Seasonal variations of dissolved organic carbon in precipitation over urban and forest sites in central Poland.

    Science.gov (United States)

    Siudek, Patrycja; Frankowski, Marcin; Siepak, Jerzy

    2015-07-01

    Spatial and temporal variability of carbon species in rainwater (bulk deposition) was studied for the first time at two sites located in urban area of Poznań City and protected woodland area (Jeziory), in central Poland, between April and December 2013. The mean concentration of total carbon (TC) for the first site was 5.86 mg L(-1), whereas for the second, 5.21 mg L(-1). Dissolved organic carbon (DOC) concentration accounted for, on average, 87 and 91 % of total carbon in precipitation at urban and non-urban sites, respectively. Significant changes in TC concentrations in rainwater were observed at both sites, indicating that atmospheric transformation, transport, and removal mechanisms of carbonaceous particles were affected by seasonal fluctuations in biogenic/anthropogenic emission and meteorological conditions (i.e., precipitation height and type, atmospheric transport). During the warm season, the DOC concentration in rainwater was mostly influenced by mixed natural and anthropogenic sources. In contrast, during the cold season, the DOC concentration significantly increased mainly as a result of anthropogenic activities, i.e., intensive coal combustion, domestic wood burning, high-temperature processes, etc. In addition, during the winter measurements, significant differences in mean DOC concentration (Kruskal-Wallis test, p urban and non-urban sites. These data imply that carbonaceous compounds are of crucial importance in atmospheric chemistry and should be considered as an important parameter while considering wet deposition, reactions with different substances, especially over polluted environments.

  16. Sources of Variation in Sweat Chloride Measurements in Cystic Fibrosis

    Science.gov (United States)

    Blackman, Scott M.; Raraigh, Karen S.; Corvol, Harriet; Rommens, Johanna M.; Pace, Rhonda G.; Boelle, Pierre-Yves; McGready, John; Sosnay, Patrick R.; Strug, Lisa J.; Knowles, Michael R.; Cutting, Garry R.

    2016-01-01

    Rationale: Expanding the use of cystic fibrosis transmembrane conductance regulator (CFTR) potentiators and correctors for the treatment of cystic fibrosis (CF) requires precise and accurate biomarkers. Sweat chloride concentration provides an in vivo assessment of CFTR function, but it is unknown the degree to which CFTR mutations account for sweat chloride variation. Objectives: To estimate potential sources of variation for sweat chloride measurements, including demographic factors, testing variability, recording biases, and CFTR genotype itself. Methods: A total of 2,639 sweat chloride measurements were obtained in 1,761 twins/siblings from the CF Twin-Sibling Study, French CF Modifier Gene Study, and Canadian Consortium for Genetic Studies. Variance component estimation was performed by nested mixed modeling. Measurements and Main Results: Across the tested CF population as a whole, CFTR gene mutations were found to be the primary determinant of sweat chloride variability (56.1% of variation) with contributions from variation over time (e.g., factors related to testing on different days; 13.8%), environmental factors (e.g., climate, family diet; 13.5%), other residual factors (e.g., test variability; 9.9%), and unique individual factors (e.g., modifier genes, unique exposures; 6.8%) (likelihood ratio test, P < 0.001). Twin analysis suggested that modifier genes did not play a significant role because the heritability estimate was negligible (H2 = 0; 95% confidence interval, 0.0–0.35). For an individual with CF, variation in sweat chloride was primarily caused by variation over time (58.1%) with the remainder attributable to residual/random factors (41.9%). Conclusions: Variation in the CFTR gene is the predominant cause of sweat chloride variation; most of the non-CFTR variation is caused by testing variability and unique environmental factors. If test precision and accuracy can be improved, sweat chloride measurement could be a valuable biomarker

  17. Seasonal changes in nutrient limitation and nitrate sources in the green macroalga Ulva lactuca at sites with and without green tides in a northeastern Pacific embayment.

    Science.gov (United States)

    Van Alstyne, Kathryn L

    2016-02-15

    In Penn Cove, ulvoid green algal mats occur annually. To examine seasonal variation in their causes, nitrogen and carbon were measured in Ulva lactuca in May, July, and September and stable nitrogen and oxygen isotope ratios were quantified in U. lactuca, Penn Cove seawater, upwelled water from Saratoga Passage, water near the Skagit River outflow, and effluents from wastewater treatment facilities. Ulvoid growth was nitrogen limited and the sources of nitrogen used by the algae changed during the growing season. Algal nitrogen concentrations were 0.85-4.55% and were highest in September and at sites where algae were abundant. Upwelled waters were the primary nitrogen source for the algae, but anthropogenic sources also contributed to algal growth towards the end of the growing season. This study suggests that small nitrogen inputs can result in crossing a "tipping point", causing the release of nutrient limitation and localized increases in algal growth. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Source attribution of light-absorbing impurities in seasonal snow across northern China

    Science.gov (United States)

    Zhang, R.; Hegg, D. A.; Huang, J.; Fu, Q.

    2013-01-01

    Seasonal snow samples obtained at 46 sites in 6 provinces of China in January and February 2010 were analyzed for a suite of chemical species and these data are combined with previously determined concentrations of light-absorbing impurities (LAI), including all particles that absorb light in the 650-700 nm wavelength interval. The LAI, together with 14 other analytes, are used as input to a positive matrix factorization (PMF) receptor model to explore the sources of the LAI in the snow. The PMF analysis for the LAI sources is augmented with backward trajectory cluster analysis and the geographic locations of major source areas for the three source types. The two analyses are consistent and indicate that three factors/sources were responsible for the measured snow light absorption: a soil dust source, an industrial pollution source, and a biomass and biofuels burning source. Soil dust was the main source of the LAI, accounting for ~ 53% of the LAI on average.

  19. Source attribution of insoluble light-absorbing particles in seasonal snow across northern China

    Science.gov (United States)

    Zhang, R.; Hegg, D. A.; Huang, J.; Fu, Q.

    2013-06-01

    Seasonal snow samples obtained at 46 sites in 6 provinces of China in January and February 2010 were analyzed for a suite of chemical species and these data are combined with previously determined concentrations of insoluble light-absorbing particles (ILAP), including all particles that absorb light in the 650-700 nm wavelength interval. The ILAP, together with 14 other analytes, are used as input to a positive matrix factorization (PMF) receptor model to explore the sources of ILAP in the snow. The PMF analysis for ILAP sources is augmented with backward trajectory cluster analysis and the geographic locations of major source areas for the three source types. The two analyses are consistent and indicate that three factors/sources were responsible for the measured light absorption of snow: a soil dust source, an industrial pollution source, and a biomass and / or biofuel burning source. Soil dust was the main source of the ILAP, accounting for ~53% of ILAP on average.

  20. [Seasonal variation of soil respiration and its components in tropical rain forest and rubber plantation in Xishuangbanna, Yunnan].

    Science.gov (United States)

    Lu, Hua-Zheng; Sha, Li-Qing; Wang, Jun; Hu, Wen-Yan; Wu, Bing-Xia

    2009-10-01

    By using trenching method and infrared gas analyzer, this paper studied the seasonal variation of soil respiration (SR), including root respiration (RR) and heterotrophic respiration (HR), in tropical seasonal rain forest (RF) and rubber (Hevea brasiliensis) plantation (RP) in Xishuangbanna of Yunnan, China. The results showed that the SR and HR rates were significantly higher in RF than in RP (P dry-hot season > foggy season, but the RR rate was rainy season > foggy season > dry-hot season in RF, and foggy season > rainy season > dry-hot season in RP. The contribution of RR to SR in RF (29%) was much lower than that in RP (42%, P < 0.01), while the contribution of HR to SR was 71% in RF and 58% in RP. When the soil temperature at 5 cm depth varied from 12 degrees C to 32 degrees C, the Q10 values for SR, HR, and RR rates were higher in RF than in RP. HR had the highest Q10 value, while RR had the lowest one.

  1. Seasonal and temporal variation in release of antibiotics in hospital wastewater: estimation using continuous and grab sampling.

    Science.gov (United States)

    Diwan, Vishal; Stålsby Lundborg, Cecilia; Tamhankar, Ashok J

    2013-01-01

    The presence of antibiotics in the environment and their subsequent impact on resistance development has raised concerns globally. Hospitals are a major source of antibiotics released into the environment. To reduce these residues, research to improve knowledge of the dynamics of antibiotic release from hospitals is essential. Therefore, we undertook a study to estimate seasonal and temporal variation in antibiotic release from two hospitals in India over a period of two years. For this, 6 sampling sessions of 24 hours each were conducted in the three prominent seasons of India, at all wastewater outlets of the two hospitals, using continuous and grab sampling methods. An in-house wastewater sampler was designed for continuous sampling. Eight antibiotics from four major antibiotic groups were selected for the study. To understand the temporal pattern of antibiotic release, each of the 24-hour sessions were divided in three sub-sampling sessions of 8 hours each. Solid phase extraction followed by liquid chromatography/tandem mass spectrometry (LC-MS/MS) was used to determine the antibiotic residues. Six of the eight antibiotics studied were detected in the wastewater samples. Both continuous and grab sampling methods indicated that the highest quantities of fluoroquinolones were released in winter followed by the rainy season and the summer. No temporal pattern in antibiotic release was detected. In general, in a common timeframe, continuous sampling showed less concentration of antibiotics in wastewater as compared to grab sampling. It is suggested that continuous sampling should be the method of choice as grab sampling gives erroneous results, it being indicative of the quantities of antibiotics present in wastewater only at the time of sampling. Based on our studies, calculations indicate that from hospitals in India, an estimated 89, 1 and 25 ng/L/day of fluroquinolones, metronidazole and sulfamethoxazole respectively, might be getting released into the

  2. Succession and seasonal variation in epilithic biofilms on artificial reefs in culture waters of the sea cucumber Apostichopus japonicus

    Science.gov (United States)

    Liu, Liming; Du, Rongbin; Zhang, Xiaoling; Dong, Shuanglin; Sun, Shichun

    2017-01-01

    Periphytic biofilms in aquaculture waters are thought to improve water quality, provide an additional food source, and improve the survival and growth of some reared animals. In the Asia- Pacific region, particularly in China, artificial reefs are commonly used in the commercial farming of sea cucumbers. However, few studies have examined the epilithic biofilms on the artificial reefs. To gain a better understanding of the succession of epilithic biofilms and their ecological processes in sea cucumber culture waters, two experiments were conducted in culture waters of the sea cucumber Apostichopus japonicus in Rongcheng, China, using artificial test panels. On the test panels of succession experiment, more than 67 species were identified in the biofilms. On the test panels of seasonal variation experiment, more than 46 species were recorded in the biofilms. In both experiments, communities of epilithic biofilms were dominated by diatoms, green algae and the annelid Spirorbis sp. In the initial colonization, the dominant diatoms were Cocconeis sp., Amphora spp. and Nitzschia closterium in June, which were succeeded by species of Navicula, Cocconeis and Nitzschia (July to September), and then by Licmophora abbreviata, Nitzschia closterium and Synedra spp. in the following months. A diatom bloom in the autumn and filamentous green algae burst in the summer were also observed. Ecological indices well annotated the succession and seasonal changes in epilithic communities. Multidimensional scaling (MDS) analysis found significant differences in diatom community composition among months and seasons. Fast growth of biofilms was observed in the summer and autumn, whereas the biomass of summer biofilms was largely made up of filamentous green algae. Present results show that the components of epilithic biofilms are mostly optimal foods of A. japonicus, suggesting that biofilms on artificial reefs may contribute important nutritional sources for sea cucumbers during their

  3. The impact of seasonal varied human activity on characteristics and sources of heavy metals in metropolitan road dusts.

    Science.gov (United States)

    Men, Cong; Liu, Ruimin; Wang, Qingrui; Guo, Lijia; Shen, Zhenyao

    2018-10-01

    Due to significant human activity, road dust is becoming contaminated by heavy metals in many cities. To comprehensively investigate the variation of contamination level and sources of heavy metals in road dust, 10 heavy metals in road dust samples from Beijing, China, in both summer and winter, were evaluated by spatial analysis using geographic information system (GIS) mapping technology and the positive matrix factorization (PMF) Model. Although the concentrations of some heavy metals between summer and winter had similarities, the differences of others and spatial distributions of heavy metals between summer and winter were considerable. The mean concentrations of As, Cd, Cr, Cu, and Fe were lower in winter, while those of Hg, Mn, Ni, Pb, and Zn were higher. According to the values of the Pollution Index (PI) and Nemerow Integrated Pollution Index (NIPI), there were no obvious differences between summer and winter, but the range between different sites in winter was nearly twice that of summer. Based on the PMF model, four sources of heavy metals in the dust samples were identified. Although the types of sources were consistent, the relative contributions of each source differed between summer and winter. Non-exhaust vehicle emissions was the most important source in summer (34.47 wt%), while fuel combustion contributed the largest proportion to the total heavy metals in winter (32.40 wt%). The impact of each source also showed spatial variation different trends in summer and winter. With the alteration of seasons, intensity of human activities also changed, such as the number of tourists, energy needs for building temperature regulation, construction, and the amount of pesticides and fertilizer. That might be the reason for the variation of heavy metal concentrations and relative contribution of their sources between summer and winter. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Seasonal variation of Martian pick-up ions: Evidence of breathing exosphere

    Science.gov (United States)

    Yamauchi, M.; Hara, T.; Lundin, R.; Dubinin, E.; Fedorov, A.; Sauvaud, J.-A.; Frahm, R. A.; Ramstad, R.; Futaana, Y.; Holmstrom, M.; Barabash, S.

    2015-12-01

    The Mars Express (MEX) Ion Mass Analyser (IMA) found that the detection rate of the ring-like distribution of protons in the solar wind outside of the bow shock to be quite different between Mars orbital summer (around perihelion) and orbital winter (around aphelion) for four Martian years, while the north-south asymmetry is much smaller than the perihelion-aphelion difference. Further analyses using eight years of MEX/IMA solar wind data between 2005 and 2012 has revealed that the detection frequency of the pick-up ions originating from newly ionized exospheric hydrogen with certain flux strongly correlates with the Sun-Mars distance, which changes approximately every two years. Variation due to the solar cycle phase is not distinguishable partly because this effect is masked by the seasonal variation under the MEX capability of plasma measurements. This finding indicates that the variation in solar UV has a major effect on the formation of the pick-up ions, but this is not the only controlling factor.

  5. Influence of seasonal variation and anthropogenic activity on phosphorus cycling and retention in mangrove sediments: A case study in China

    Science.gov (United States)

    Jiang, Shan; Lu, Haoliang; Liu, Jingchun; Lin, Yushan; Dai, Minyue; Yan, Chongling

    2018-03-01

    Mangroves are known for sequestering and storing large quantities of phosphorus (P) within their sediments. In the present study, the sediment P cycle (including phosphatase activity intensity, total sedimentary P, P fractions distinguished by a sequential extraction method, as well as diffusion-adsorption processes) in a mangrove swamp in a subtropical estuary in China was studied. In the spring, the acid phosphatase activity varied between 1.3 and 1.9 units in the four sites in the estuary. The activity of alkaline phosphatase varied from 0.8 to 1.4 units. The total sedimentary P ranged from 821 to 1689 mg kg-1 with a dominance of redox-sensitive (Fe/Al bound) P. In the autumn, activities of both phosphatases and the total sediment P amount increased, probably due to enhanced inputs of organic matter and Fe oxides. In addition to seasonal variation, P in the mangrove sediment was influenced by anthropogenic activities. In particular, redox-sensitive P decreased significantly while phosphatase activity increased in the site that was flushed with aquaculture pond effluents. In contrast, sediment P enrichment was observed in the site that received domestic sewage. Both sources of anthropogenic P increased the eutrophication risk of the mangrove sediment because of a decrease in the amount of P adsorption and an enhancement of P release via diffusion. Diesel contamination due to the presence of a dock depressed phosphatase activity in the surficial sediment. The overlap between seasonal rhythm and human influences may introduce significant variations in P cycling, which warrants further attention from coastal management.

  6. Seasonal variation of early diagenesis and greenhouse gas production in coastal sediments of Cadiz Bay: Influence of anthropogenic activities

    Science.gov (United States)

    Burgos, Macarena; Ortega, Teodora; Bohórquez, Julio; Corzo, Alfonso; Rabouille, Christophe; Forja, Jesús M.

    2018-01-01

    Greenhouse gas production in coastal sediments is closely associated with the early diagenesis processes of organic matter and nutrients. Discharges from anthropogenic activities, particularly agriculture, fish farming and waste-water treatment plants supply large amounts of organic matter and inorganic nutrients that affect mineralization processes. Three coastal systems of Cadiz Bay (SW Spain) (Guadalete River, Rio San Pedro Creek and Sancti Petri Channel) were chosen to determine the seasonal variation of organic matter mineralization. Two sampling stations were selected in each system; one in the outer part, close to the bay, and another more inland, close to a discharge point of effluent related to anthropogenic activities. Seasonal variation revealed that metabolic reactions were driven by the annual change of temperature in the outer station of the systems. In contrast, these reactions depended on the amount of organic matter reaching the sediments in the outermost part of the systems, which was higher during winter. Oxygen is consumed in the first 0.5 cm indicating that suboxic and anoxic processes, such as denitrification, sulfate reduction and methanogenesis are important in these sediments. Sulfate reduction seems to account for most of the mineralization of organic matter at the marine stations, while methanogenesis is the main pathway at the sole freshwater station of this study, located inside the estuary of the Guadalete River, because of the lack of sulfate as electron acceptor. Results point to denitrification being the principal process of N2O formation. Diffusive fluxes varied between 2.6 and 160 mmol m-2 d-1 for dissolved inorganic carbon (DIC); 0.9 and 164.3 mmol m-2 d-1 for TA; 0.8 and 17.4 μmol m-2 d-1 for N2O; and 0.1 μmol and 13.1 mmol m-2 d-1 for CH4, indicating that these sediments act as a source of greenhouse gases to the water column.

  7. Variations of Mercury Concentrations in American Beech Foliage over a Growing Season

    Science.gov (United States)

    Stinson, I.; Tsui, M. T. K.; Chow, A. T.

    2017-12-01

    Accumulation of atmospheric gaseous mercury (Hg) in foliage is well known, however, a small fraction of Hg always exists as highly bioavailable methylmercury (MeHg) in foliage but the source of MeHg in foliage is unknown. Recent studies suggested in-vivo Hg methylation in foliage while others suggested external inputs (e.g., precipitation) as sources of MeHg in foliage. This study assesses the accumulation of total Hg and MeHg within the foliage of a small sample set of American Beech trees, one of the common tree species in the east coast and the study site is located within the campus of University of North Carolina - Greensboro, over the growing season in 2017 (spring, summer, and fall). In addition, this study evaluates the Hg concentrations in foliage as related to other physiological parameters (e.g., stomatal density, leaf area, chlorophyll, and carbon/nitrogen content) and the changes in environmental characteristics (e.g., sunlight) over the growing season. For this investigation, five American Beech trees with varying characteristics (height, age, and location) were selected. On a biweekly basis, starting late April 2017, foliage samples were collected and composited from different positions on each tree. For the samples processed to date, our results indicate that total Hg accumulation is occurring for all five trees with an initial mean value of 5.79 ng/g, increasing to a mean value of 13.9 ng/g over a ten-week period. Coincidentally, there has been a similar increase in chlorophyll (a+b) concentrations for the foliage, and there is a strong, positive relationship between chlorophyll and total-Hg concentrations. However, we found no relationships between total Hg concentrations and stomatal density of foliage or carbon/nitrogen content. This study is still ongoing and will continue through the end of the growing season in 2017. Additionally, from the same sample sets, besides total Hg analysis and other ancillary parameters in foliage, MeHg analysis

  8. A source of parametric variation in the lexicon

    Directory of Open Access Journals (Sweden)

    Guglielmo Cinque

    2016-12-01

    Full Text Available An influential conjecture concerning parameters is that they can possibly be “restricted to formal features of functional categories” (Chomsky 1995: 6. In Rizzi (2009, 2011 such features are understood as instructions triggering one of the following syntactic actions: (1 External Merge; (2 Internal Merge (Move; (3 Pronunciation/Non pronunciation (the latter arguably dependent on Internal Merge – Kayne 2005a, b. In this article I consider a particular source of parametric variation across languages in the domain of the lexicon (both functional and substantive which appears to be due to the possibility of underspecifying certain features in some languages. The paradigmatic variation can be characterized as follows: language A has two (or more lexical items which correspond to just one lexical item in language B.

  9. Source seasonality of polycyclic aromatic hydrocarbons (PAHs) in a subtropical city, Guangzhou, South China.

    Science.gov (United States)

    Li, J; Zhang, G; Li, X D; Qi, S H; Liu, G Q; Peng, X Z

    2006-02-15

    Mega-cities are large sources of air pollution on a regional base. Differences in energy structures, geographical settings and regional climate features lead to a large variety of air pollution sources from place to place. To understand the seasonality of air pollution sources is critical to precise emission inventories and a sound protection of human health. Based on a year-round dataset, the sources of PAHs in the air of Guangzhou were drawn by principal factor analysis (PCA) in combination with diagnostic ratios, and the seasonality of these sources were analyzed by PCA/MLR (multiple linear regressions) and discussed. The average total gaseous and particulate PAHs concentrations were 313 and 23.7 ng m(-3), respectively, with a higher concentration of vapor PAHs in summer and particulate PAHs in winter. In addition to vehicle exhaust, which contributed 69% of the particulate PAHs, coal combustion was still an important source and contributed 31% of the particulate PAHs. Relatively constant contribution from coal combustion was found through the year, implying that coal combustion in power plants was not a seasonally dependent source. Evaporation from contaminated ground may be an important source of light PAHs in summer, providing an average contribution of 68% to the total PAHs in this study. By comparing the PAH concentrations and meteorological parameters, we found that higher concentrations of particulate PAHs in winter resulted from enhanced vehicle exhaust under low temperature and accumulation of pollutants under decreased boundary layer, slower wind speed, and long-term dryness conditions. It is suggested that the typical subtropical monsoon climate in South China, cool and dry in winter, hot and humid in summer, may play a key role in controlling the source seasonality (by enhancing vehicle exhaust in winter, ground evaporation in summer), and hence the ambient concentrations of PAHs in the air.

  10. Estimates of eddy turbulence consistent with seasonal variations of atomic oxygen and its possible role in the seasonal cycle of mesopause temperature

    Directory of Open Access Journals (Sweden)

    M. N. Vlasov

    2010-11-01

    Full Text Available According to current understanding, adiabatic cooling and heating induced by the meridional circulation driven by gravity waves is the major process for the cold summer and warm winter polar upper mesosphere. However, our calculations show that the upward/downward motion needed for adiabatic cooling/heating of the summer/winter polar mesopause simultaneously induces a seasonal variation in both the O maximum density and the altitude of the [O] peak that is opposite to the observed variables generalized by the MSISE-90 model. It is usually accepted that eddy turbulence can produce the [O] seasonal variations. Using this approach, we can infer the eddy diffusion coefficient for the different seasons. Taking these results and experimental data on the eddy diffusion coefficient, we consider in detail and estimate the heating and cooling caused by eddy turbulence in the summer and winter polar upper mesosphere. The seasonal variations of these processes are similar to the seasonal variations of the temperature and mesopause. These results lead to the conclusion that heating/cooling by eddy turbulence is an important component in the energy budget and that adiabatic cooling/heating induced by upward/downward motion cannot dominate in the mesopause region. Our study shows that the impact of the dynamic process, induced by gravity waves, on [O] distributions must be included in models of thermal balance in the upper mesosphere and lower thermosphere (MLT for a consistent description because (a the [O] distribution is very sensitive to dynamic processes, and (b atomic oxygen plays a very important role in chemical heating and infrared cooling in the MLT. To our knowledge, this is the first attempt to consider this aspect of the problem.

  11. Seasonal Variation of Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae Bacteremia According to Acquisition and Patient Characteristics

    DEFF Research Database (Denmark)

    Gradel, Kim Oren; Nielsen, Stig Lønberg; Pedersen, Court

    2016-01-01

    subgroups by combining the following characteristics: species, acquisition, age group, gender, CCI level, and location of infection. Assuming a sinusoidal model, seasonal variation was assessed by the peak-to-trough (PTT) ratio with a 95% confidence interval (CI). RESULTS In total, we included 16,006 E...... variation was observed for S. aureus. S. pneumoniae showed high seasonal variation, which did not differ according to acquisition (overall PTT ratio, 3.42; 95% CI, 3.10-3.83). CONCLUSIONS Seasonal variation was mainly related to the species although the place of acquisition was important for E. coli. Infect....... coli, 6,924 S. aureus, and 4,884 S. pneumoniae bacteremia cases. For E. coli, the seasonal variation was highest for community-acquired cases (PTT ratio, 1.24; 95% CI, 1.17-1.32), was diminished for HCA (PTT ratio, 1.14; 95% CI, 1.04-1.25), and was missing for hospital-acquired cases. No seasonal...

  12. Multivariate analysis of effects of diurnal temperature and seasonal humidity variations by tropical savanna climate on the emissions of anthropogenic volatile organic compounds.

    Science.gov (United States)

    Liu, Chih-Chung; Chen, Wei-Hsiang; Yuan, Chung-Shin; Lin, Chitsan

    2014-02-01

    Volatile organic compounds (VOCs), particularly those from anthropogenic sources, have been of substantial concern. In this study, the influences of diurnal temperature and seasonal humidity variations by tropical savanna climate on the distributions of VOCs from stationary industrial sources were investigated by analyzing the concentrations during the daytime and nighttime in the dry and wet seasons and assessing the results by principal component analysis (PCA) and cluster analysis. Kaohsiung City in Southern Taiwan, known for its severe VOC pollution, was chosen as the location to be examined. In the results, the VOC concentrations were lower during the daytime and in the wet season, possibly attributed to the stronger photochemical reactions and increasing inhibition of VOC emissions and transports by elevating humidity levels. Certain compounds became appreciably more important at higher humidity, as these compounds were saturated hydrocarbons with relatively low molecular weights. The influence of diurnal temperature variation on VOC distribution behaviors seemed to be less important than and interacted with that of seasonal humidity variation. Heavier aromatic hydrocarbons with more complex structures and some aliphatic compounds were found to be the main species accounting for the maximum variances of the data observed at high humidity, and the distinct grouping of compounds implied a pronounced inherent characteristic of each cluster in the observed VOC distributions. Under the influence of diurnal temperature variation, selected VOCs that may have stronger photochemical resistances and/or longer lifetimes in the atmosphere were clustered with each other in the cluster analysis, whereas the other groups might consist of compounds with different levels of vulnerability to sunlight or high temperatures. These findings prove the complications in the current knowledge regarding the VOC contaminations and providing insight for managing the adverse impacts of

  13. Variations in Growing-Season NDVI and Its Response to Permafrost Degradation in Northeast China

    Directory of Open Access Journals (Sweden)

    Jinting Guo

    2017-04-01

    Full Text Available Permafrost is extremely sensitive to climate change. The degradation of permafrost has strong and profound effects on vegetation. The permafrost zone of northeastern China is the second largest region of permafrost in China and lies on the south edge of the Eurasian cryolithozone. This study analyzed the spatiotemporal variations of the growing-season Normalization Difference Vegetation Index (NDVI in the permafrost zone of northeastern China and analyzed the correlation between NDVI and ground surface temperatures (GST during the years 1981–2014. Mean growing-season NDVI (MGS-NDVI experienced a marked increase of 0.003 year−1 across the entire permafrost zone. The spatial dynamics of vegetation cover had a high degree of heterogeneity on a per pixel scale. The MGS-NDVI value increased significantly (5% significance level in 80.57%, and this increase was mostly distributed in permafrost zone except for the western steppe region. Only 7.72% experienced a significant decrease in NDVI, mainly in the cultivated and steppe portions. In addition, MGS-NDVI increased significantly with increasing growing-season mean ground surface temperature (GS-MGST. Our results suggest that a warming of GS-MGST (permafrost degradation in the permafrost region of northeastern China played a positive role in increasing plant growth and activities. Although increasing ground surface temperature resulted in increased vegetation cover and growth in the short time of permafrost degradation, from the long term point of view, permafrost degradation or disappearance may weaken or even hinder vegetation activities.

  14. Seasonal variation in plasma lipids and lipases in young healthy humans.

    Science.gov (United States)

    Cambras, Trinitat; Baena-Fustegueras, Juan A; Pardina, Eva; Ricart-Jané, David; Rossell, Joana; Díez-Noguera, Antoni; Peinado-Onsurbe, Julia

    2017-01-01

    Although intermediate metabolism is known to follow circadian rhythms, little information is available on the variation in lipase activities (lipoprotein and hepatic lipase, LPL and HL, respectively) and lipids throughout the year. In a cross-sectional study, we collected and analysed blood from 245 healthy students (110 men and 135 women) between 18 and 25 years old from the University of Barcelona throughout the annual campaign (March, May, October and December) of the blood bank. All subjects gave their written informed consent to participate. All blood samples were taken after breakfast at 8:00 and 11:00 am. Plasma glucose, total plasma protein, triacylglycerides (TAG), free fatty acids (FFA), free cholesterol and esterified cholesterol (FC and TC, respectively), cholesterol in low-density lipoproteins (cLDL), cholesterol in high-density lipoproteins (cHDL), phospholipids (PL) and lipase activities (LPL and HL) were determined. Cosinor analysis was used to evaluate the presence (significance of fit cosine curve to data and variance explained by rhythm) and characteristics of possible 12-month rhythms (acrophase, MESOR and amplitude). Statistically significant seasonal rhythms were detected for all the variables studied except proteins, with most of them peaking in the winter season. The lowest value for cLDL and the HL occurs in summer, while for cHDL and the LPL it is in winter. These findings demonstrate for the first time that in physiological conditions, plasma LPL and HL activities and lipids follow seasonal rhythms. The metabolic significance of this pattern is discussed.

  15. Assessment of carbonaceous aerosols in Shanghai, China - Part 1: long-term evolution, seasonal variations, and meteorological effects

    Science.gov (United States)

    Chang, Yunhua; Deng, Congrui; Cao, Fang; Cao, Chang; Zou, Zhong; Liu, Shoudong; Lee, Xuhui; Li, Jun; Zhang, Gan; Zhang, Yanlin

    2017-08-01

    Carbonaceous aerosols are major chemical components of fine particulate matter (PM2. 5) with major impacts on air quality, climate change, and human health. Gateway to fast-rising China and home of over twenty million people, Shanghai throbs as the nation's largest mega city and the biggest industrial hub. From July 2010 to December 2014, hourly mass concentrations of ambient organic carbon (OC) and elemental carbon (EC) in the PM2. 5 fraction were quasi-continuously measured in Shanghai's urban center. The annual OC and EC concentrations (mean ±1σ) in 2013 (8.9 ± 6.2 and 2.6 ± 2.1 µg m-3, n = 5547) and 2014 (7.8 ± 4.6 and 2.1 ± 1.6 µg m-3, n = 6914) were higher than those of 2011 (6.3 ± 4.2 and 2.4 ± 1.8 µg m-3, n = 8039) and 2012 (5.7 ± 3.8 and 2.0 ± 1.6 µg m-3, n = 4459). We integrated the results from historical field measurements (1999-2012) and satellite observations (2003-2013), concluding that carbonaceous aerosol pollution in Shanghai has gradually reduced since 2006. In terms of monthly variations, average OC and EC concentrations ranged from 4.0 to 15.5 and from 1.4 to 4.7 µg m-3, accounting for 13.2-24.6 and 3.9-6.6 % of the seasonal PM2. 5 mass (38.8-94.1 µg m-3), respectively. The concentrations of EC (2.4, 2.0, 2.2, and 3.0 µg m-3 in spring, summer, fall, and winter, respectively) showed little seasonal variation (except in winter) and weekend-weekday dependence, indicating EC is a relatively stable constituent of PM2. 5 in the Shanghai urban atmosphere. In contrast to OC (7.3, 6.8, 6.7, and 8.1 µg m-3 in spring, summer, fall, and winter, respectively), EC showed marked diurnal cycles and correlated strongly with CO across all seasons, confirming vehicular emissions as the dominant source of EC at the targeted site. Our data also reveal that both OC and EC showed concentration gradients as a function of wind direction (WD) and wind speed (WS), generally with higher values associated with winds from the southwest, west, and northwest

  16. Assessment of carbonaceous aerosols in Shanghai, China – Part 1: long-term evolution, seasonal variations, and meteorological effects

    Directory of Open Access Journals (Sweden)

    Y. Chang

    2017-08-01

    Full Text Available Carbonaceous aerosols are major chemical components of fine particulate matter (PM2. 5 with major impacts on air quality, climate change, and human health. Gateway to fast-rising China and home of over twenty million people, Shanghai throbs as the nation's largest mega city and the biggest industrial hub. From July 2010 to December 2014, hourly mass concentrations of ambient organic carbon (OC and elemental carbon (EC in the PM2. 5 fraction were quasi-continuously measured in Shanghai's urban center. The annual OC and EC concentrations (mean ±1σ in 2013 (8.9 ± 6.2 and 2.6 ± 2.1 µg m−3, n =  5547 and 2014 (7.8 ± 4.6 and 2.1 ± 1.6 µg m−3, n =  6914 were higher than those of 2011 (6.3 ± 4.2 and 2.4 ± 1.8 µg m−3, n =  8039 and 2012 (5.7 ± 3.8 and 2.0 ± 1.6 µg m−3, n =  4459. We integrated the results from historical field measurements (1999–2012 and satellite observations (2003–2013, concluding that carbonaceous aerosol pollution in Shanghai has gradually reduced since 2006. In terms of monthly variations, average OC and EC concentrations ranged from 4.0 to 15.5 and from 1.4 to 4.7 µg m−3, accounting for 13.2–24.6 and 3.9–6.6 % of the seasonal PM2. 5 mass (38.8–94.1 µg m−3, respectively. The concentrations of EC (2.4, 2.0, 2.2, and 3.0 µg m−3 in spring, summer, fall, and winter, respectively showed little seasonal variation (except in winter and weekend–weekday dependence, indicating EC is a relatively stable constituent of PM2. 5 in the Shanghai urban atmosphere. In contrast to OC (7.3, 6.8, 6.7, and 8.1 µg m−3 in spring, summer, fall, and winter, respectively, EC showed marked diurnal cycles and correlated strongly with CO across all seasons, confirming vehicular emissions as the dominant source of EC at the targeted site. Our data also reveal that both OC and EC showed concentration gradients as a

  17. Studies on the seasonal variation of atmospheric electricity parameters at a tropical station in Kolkata, India

    Science.gov (United States)

    De, S. S.; Paul, Suman; Barui, S.; Pal, Pinaki; Bandyopadhyay, B.; Kala, D.; Ghosh, A.

    2013-12-01

    The paper deals with the analyses of the atmospheric vertical potential gradient (PG) from the ground for 90 fair weather days during 2006-2009 measured at Kolkata (Lat: 22.56°N). The variations of PG have been studied extensively to investigate their values during monsoon and winter seasons. Higher values of PG at Kolkata are observed due to higher abundance of pollutant particles. The observed PG are compared with the results of Potsdam station (Lat: 52°N) and Johannesburg station (Lat: 26°S), with 9 years data and 2 years data respectively. The correlations studies are carried out among PG, PDC (Point Discharge Current) as well as negative and positive carrier conductivities. The corresponding correlation coefficients are obtained as 0.93, -0.842 and -0.844.

  18. Seasonal variation of water quality in a lateral hyporheic zone with response to dam operations

    Science.gov (United States)

    Chen, X.; Chen, L.; Zhao, J.

    2015-12-01

    Aquatic environment of lateral hyporheic zone in a regulated river were investigated seasonally under fluctuated water levels induced by dam operations. Groundwater levels variations in preassembled wells and changes in electronic conductivity (EC), dissolved oxygen (DO) concentration, water temperature and pH in the hyporheic zone were examined as environmental performance indicators for the water quality. Groundwater tables in wells were highly related to the river water levels that showed a hysteresis pattern, and the lag time is associated with the distances from wells to the river bank. The distribution of DO and EC were strongly related to the water temperature, indicating that the cold water released from up-reservoir could determine the biochemistry process in the hyporheic zone. Results also showed that the hyporheic water was weakly alkaline in the study area but had a more or less uniform spatial distribution. Dam release-storage cycles were the dominant factor in changing lateral hyporheic flow and water quality.

  19. Seasonal variation in bioaerosol exposure during biowaste collection and measurements of leaked percolate

    DEFF Research Database (Denmark)

    Nielsen, Birgitte Herbert; Nielsen, Eva Møller; Breum, Niels O.

    2000-01-01

    The seasonal variation in waste collectors' exposure to microorganisms, endotoxin and dust was measured with personal sampling equipment. The measurement was carried out in three different combinations of storage and collection system for biowaste: container/compactor truck (CIC), paper sack....../compactor truck (P/C) and paper sack/platform truck (P/P). The maximum personal exposure was found to occur during the summer at the following median levels: total microorganisms 9.2 x 10(5) cells m(-3), culturable fungi (moulds) 7.8 x 10(4) cfu m(-3), Aspergillus fumigatus 2.9 x 10(-3) cfu m(3), mesophilic...... and endotoxin occurred in the CIC system (P trucks. Concentrations of endotoxin ranged from 3.9 to 6.1 x 10(5) EU ml(-1) (25 to 52 mu g ml(-1)) and the microflora of the percolate was dominated by bacteria (1...

  20. Seasonal latitudinal and secular variations in temperature trend - evidence for influence of anthropogenic sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Hunter, D E; Schwartz, S E; Wagener, R; Benkovitz, C M [University of California at San Diego, La Jolla, CA (United States). Scripps Institute of Oceanography

    1993-11-19

    Tropospheric aerosols increase the shortwave reflectivity of the Earth-atmosphere system both by scattering light directly, in the absence of clouds, and by enhancing cloud reflectivity. The radiative forcing of climate exerted by anthropogenic sulfate aerosols, derived mainly from SO[sub 2] emitted from fossil fuel combustion, is opposite that due to anthropogenic greenhouse gases and is estimated to be of comparable average magnitude in Northern Hemisphere midlatitudes. However, persuasive evidence of climate response to this forcing has thus far been lacking. Here we examine patterns of seasonal and latitudinal variations in temperature anomaly trend for evidence of such a response. Pronounced minima in the rate of temperature increase in summer months in Northern Hemisphere midlatitudes are consistent with the latitudinal distribution of anthropogenic sulfate and changes in the rate of SO[sub 2] emissions over the industrial era.

  1. Seasonal variations in the composition of the essential oils of Lavandula angustifolia (Lamiacae).

    Science.gov (United States)

    Lakusić, Branislava; Lakusić, Dmitar; Ristić, Mihailo; Marcetić, Mirjana; Slavkovska, Violeta

    2014-06-01

    Seasonal variations in the composition of the essential oils obtained from the same individual (of the same genotype) of Lavandula angustifolia cultivated in Belgrade were determined by GC and GC/MS. The main constituents were 1,8-cineole (7.1-48.4%), linalool (0.1-38.7%), bomeol (10.9-27.7%), beta-phellandrene (0.5-21.2%) and camphor (1.5-15.8%). Cluster analysis showed that the 21 samples collected each month during the vegetation cycle were separable into three main clades with different compositions of essential oils. In the shoots with flowers, inflorescences and fruits of clade I, linalool is dominant, in the young leaves before flowering and old leaves of clade II, 1,8-cineole is dominant. In the young and incompletely developed leaves of clade III, beta-phellandrene is dominant. The composition of the essential oils of lavender depended on the plant part and the stage of development.

  2. Seasonal variation of chemical composition and biomethane production from the brown seaweed Ascophyllum nodosum.

    Science.gov (United States)

    Tabassum, Muhammad Rizwan; Xia, Ao; Murphy, Jerry D

    2016-09-01

    Ascophyllum nodosum, an abundant Irish brown seaweed, shows significant seasonal variation in chemical composition and biogas production. The polyphenol content is shown to be a more important factor in biogas production than ash content. High polyphenol content in summer months adversely affected biogas production; suggesting two potential harvest dates, March and October. A. nodosum harvested in October showed a relatively low level of polyphenols (2% of TS) and ash (23% of volatile solids), and exhibited a specific methane yield of 215LCH4kgVS(-1), which was 44% of theoretical yield. The highest yield per wet weight of 47m(3)CH4t(-1) was achieved in October, which is 2.9 times higher than the lowest value (16m(3)CH4t(-1)), obtained in December. The gross energy yield of A. nodosum based on the optimal biogas production can achieve 116GJha(-1)yr(-1) in October. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Seasonal variation in the acute presentation of urinary calculi over 8 years in Auckland, New Zealand.

    Science.gov (United States)

    Lo, Sum Sum; Johnston, Richard; Al Sameraaii, Ahmed; Metcalf, Patricia A; Rice, Michael L; Masters, Jonathan G

    2010-07-01

    Symptom prevalence (retrospective cohort) Level of Evidence 2b. To determine the incidence of acute presentation of urinary calculi (UC) in Auckland, New Zealand, during the period 1999-2007, and whether there was any significant seasonal variation. The details of all UC within the population presenting acutely to public hospitals in Auckland between 1999 and 2007 were collected using clinical coding searches International Classification of Disease 10th revision (Australian Modification) N132 and N20. Climatic variables for the Auckland region were obtained from the National Institute of Water and Atmospheric Research, New Zealand. The mean atmospheric temperature, hours of sunshine and humidity data were calculated monthly for this period. During the study there were 7668 acute presentations of UC in the Auckland region. A Poisson regression model showed that the number of presentations was significantly related to temperature (P Auckland, New Zealand, varies significantly with temperature and hours of sunshine. Humidity was not a significant factor.

  4. Causes of seasonal variations of Cs-134/137 activity concentrations in surface air

    International Nuclear Information System (INIS)

    Hoetzl, H.; Winkler, R.

    1993-01-01

    In winter months maxima of Cs-134/137 activity concentrations in air are observed at several locations in Europe. To clarify this phenomenon, from October 1991 to November 1992 we performed a program for aerosol collection on a short-term scale based on collecting intervals of 48-72 hours. The local meteorological parameters were determined simultaneously. Statistical analysis of these observations reveiled a highly significant positive correlation between Cs-137 activity concentration and the so-called 'Stagnationsindex'. Based on this relationship the seasonal variations of Cs-134/137 concentrations in ground-level air can be explained by atmospheric inversion conditions frequently occurring during fall- and wintermonths. (orig.) [de

  5. Geographical, and seasonal variation in the diet of harbour porpoises (Phocoena phocoena in Icelandic coastal waters

    Directory of Open Access Journals (Sweden)

    Gísli A Víkingsson

    2003-07-01

    Overall capelin (Mallotus villosus comprised the predominant prey, followed by sandeel (Ammodytidae sp., then gadids, cephalopods and redfish (Sebastes marinus, while other taxa were of less importance. Differences were detected in diet composition among 5 areas around Iceland with redfish and gadids more prominent in the northern areas. Off SW Iceland there was considerable seasonal variation in the porpoise diet, where capelin appeared to be dominant in late winter and spring and sandeel in the summer through early winter. Predominance of capelin in the diet coincided with the spawning migration of capelin from northern waters along the east, south and west coasts of Iceland. Mature females appeared to have a more diverse diet than other reproductive classes. The length distributions of fish consumed by the porpoises ranged from 1 to 51 cm although most fish prey were less than 30 cm.

  6. Seasonal variations in chromium concentration in urban atmospheric aerosol in the city of Radom

    Directory of Open Access Journals (Sweden)

    Molik Artur

    2018-01-01

    Full Text Available This paper presents seasonal variations in the occurrence of chromium in urban particulate matter (PM. Radom is an interesting area for this type of research due to its typical antiquated heating infrastructure. PM samples of two particulate fractions PM2.5 (particulates ≤ 2.5 µm and PM10 (particulates ≤ 10 µm were collected using a Copley cascade impactor Hi-Flow MOUDI Model 130. Chromium was determined in the samples using the GF-AAS technique. The concentration of chromium in PM2.5 was in the range of 0.38 to 3.2 ng/m3, whereas in PM10 it ranged from 0.43 to 4.1 ng/m3.

  7. Studies on seasonal variation in water quality parameters of Rana Pratap Sagar lake (1996-99)

    International Nuclear Information System (INIS)

    Verma, R.; Rout, D.; Purohit, K.C.

    2000-01-01

    Water- chemistry monitoring identifies the concentration and patterns of fluctuation in chemical constituents. This information is essential to project future trends monitoring in Lake Water chemistry to identify any potential for affecting plant operation through scaling or corrosion of the circulating and service-water system equipment. Regular water chemistry monitoring provides a useful record of past. This record helps in identification of conditions that would impair station operations before their onset, allowing remedial action to be undertaken before plant performance is significantly affected. Preventive action to control the parameters influencing the corrosion, scaling and bio-fouling in the cooling system, in turn, eliminates excessive maintenance and premature replacement that otherwise would result from damage caused by unforeseen changes in the cooling water. This paper highlights the systematic monitoring approach for the variation of chemical parameters influenced by the seasonal changes in a total period of four years. (author)

  8. Seasonal variation in penicillin use in Mexico and Brazil: analysis of the impact of over-the-counter restrictions.

    Science.gov (United States)

    Santa-Ana-Tellez, Yared; Mantel-Teeuwisse, Aukje K; Leufkens, Hubert G M; Wirtz, Veronika J

    2015-01-01

    During 2010, Mexico and Brazil implemented policies to enforce existing laws of restricting over-the-counter sales of antibiotics. We determined if the enforcement led to more appropriate antibiotic use by measuring changes in seasonal variation of penicillin use. We used retail quarterly sales data in defined daily doses per 1,000 inhabitant-days (DDD/TID) from IMS Health from the private sector in Mexico and Brazil from the first quarter of 2007 to the first quarter of 2013. This database contains information on volume of antibiotics sold in retail pharmacies using information from wholesalers. We used interrupted time-series models controlling for external factors with the use of antihypertensives with interaction terms to assess changes in trend, level, and variation in use between quarters for total penicillin use and by active substance. The most used penicillin was amoxicillin, followed by amoxicillin-clavulanic acid and ampicillin (minimal use in Brazil). Before the restrictions, the seasonal variation in penicillin use was 1.1 DDD/TID in Mexico and 0.8 DDD/TID in Brazil. In Mexico, we estimated a significant decrease in the seasonal variation of 0.4 DDD/TID after the restriction, mainly due to changes in seasonal variation of amoxicillin and ampicillin. In Brazil, the seasonal variation did not change significantly, overall and in the breakdown by individual active substances. For Mexico, inappropriate penicillin use may have diminished after the restrictions were enforced. For Brazil, increasing use and no change in seasonal variation suggest that further efforts are needed to reduce inappropriate penicillin use. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  9. Seasonal Variation in Penicillin Use in Mexico and Brazil: Analysis of the Impact of Over-the-Counter Restrictions

    Science.gov (United States)

    Santa-Ana-Tellez, Yared; Mantel-Teeuwisse, Aukje K.; Leufkens, Hubert G. M.

    2014-01-01

    During 2010, Mexico and Brazil implemented policies to enforce existing laws of restricting over-the-counter sales of antibiotics. We determined if the enforcement led to more appropriate antibiotic use by measuring changes in seasonal variation of penicillin use. We used retail quarterly sales data in defined daily doses per 1,000 inhabitant-days (DDD/TID) from IMS Health from the private sector in Mexico and Brazil from the first quarter of 2007 to the first quarter of 2013. This database contains information on volume of antibiotics sold in retail pharmacies using information from wholesalers. We used interrupted time-series models controlling for external factors with the use of antihypertensives with interaction terms to assess changes in trend, level, and variation in use between quarters for total penicillin use and by active substance. The most used penicillin was amoxicillin, followed by amoxicillin-clavulanic acid and ampicillin (minimal use in Brazil). Before the restrictions, the seasonal variation in penicillin use was 1.1 DDD/TID in Mexico and 0.8 DDD/TID in Brazil. In Mexico, we estimated a significant decrease in the seasonal variation of 0.4 DDD/TID after the restriction, mainly due to changes in seasonal variation of amoxicillin and ampicillin. In Brazil, the seasonal variation did not change significantly, overall and in the breakdown by individual active substances. For Mexico, inappropriate penicillin use may have diminished after the restrictions were enforced. For Brazil, increasing use and no change in seasonal variation suggest that further efforts are needed to reduce inappropriate penicillin use. PMID:25313222

  10. Characterization and tropical seasonal variation of leachate: results from landfill lysimeter studied.

    Science.gov (United States)

    Rafizul, Islam M; Alamgir, Muhammed

    2012-11-01

    This study aims to characterize the leachate and to investigate the tropical climatic influence on leachate characteristics of lysimeter studies under different seasonal variations at KUET campus, Bangladesh. Three different situations of landfill were considered here as well as both the open dump lysimeter-A having a base liner and sanitary landfill lysimeter-B and C at two different types of cap liner were simulated. The leachate characteristics, leachate generation and climatic influence parameter had been continually monitored since June 2008 to May 2010, these periods cover both the dry and rainy season. The leachate generation had followed the rainfall pattern and the open dump lysimeter-A without top cover was recorded to have highest leachate generation. Moreover, the open dump lysimeter-A had lower total kjeldahl nitrogen (TKN), ammonia nitrogen (NH(4)-N) and TKN load, while both the COD concentration and load was higher compared with sanitary landfill lysimeter-B and C. In addition, sanitary landfill lysimeter-B, not only had lowest leachate generation, but also produces reasonable low COD concentration and load compared with open dump lysimeter-A. Result reveals that lysimeter operational mode had direct effect on leachate quality. Finally, it can be concluded that the knowledge of leachate quality will be useful in planning and providing remedial measures of proper liner system in sanitary landfill design and leachate treatment. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Seasonal variation in the environmental background level of cosmic ray produced 22Na

    International Nuclear Information System (INIS)

    Tokuyama, Hideki; Igarashi, Shuichi

    1998-01-01

    22 Na (half life 2.6 year) is produced by cosmic rays, nuclear test and reactor. 7 Be (half life 53.3 day) is produced in atmosphere by reaction. 7 Be/ 22 Na activity ratio is good factor to observe the mixing process between stratosphere and troposphere atmosphere. The seasonal variation of 7 Be and 22 Na deposition, the ratio and the background level of 22 Na deposition were observed in Fukui city and reported in this paper. Very large reasonable change of 22 Na deposition was observed, especially the largest peak in winter. Because the concentration of cosmic-ray-produced nuclear in precipitation and the amount of precipitation were large in winter. 22 Na produced by the previous nuclear test was attenuated. The present 22 Na is only produced by cosmic rays, indicating the background level. 22 Na deposition at Fukui was 0.42Bq m -2 y -1 , one ten-thousandth of 7 Be deposition. 7 Be/ 22 Na activity ratio was changed in season and the largest peak was shown in autumn. In this reason, atmosphere showed relatively short residence time in the lower part of stratosphere, Mixture and exchange of atmosphere between stratosphere and troposphere were the most active in autumn. (S.Y.)

  12. Seasonal variation in composition and abundance of harmful dinoflagellates in Yemeni waters, southern Red Sea.

    Science.gov (United States)

    Alkawri, Abdulsalam

    2016-11-15

    General abundance and species composition of a dinoflagellate community in Yemeni coastal waters of Al Salif (southern Red Sea) were studied with a view to understand the annual variations in particular the toxic species. Dinoflagellates were more abundant among phytoplankton. Thirty five dinoflagellate taxa were identified, among which 12 were reported as potentially toxic species. A significant change in seasonal abundance was recorded with the maximum (2.27∗10 6 cellsl -1 ) in May, and the minimum (2.50∗10 2 cellsl -1 ) recorded in January. Kryptoperidinium foliaceum, which was reported for the first time from the Red Sea, was the most abundant species with a maximum in May 2013 (2.26∗10 6 cellsl -1 ). Spearman's rank correlation analysis indicates that, total harmful dinoflagellate cells, K. foliaceum, Prorocentrum gracile and Prorocentrum micans were significantly correlated with temperature. This study suggests that Yemeni waters should be monitored to investigate harmful species and to identify areas and seasons at higher risk. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Seasonal Variation on Microbial Community and Methane Production during Anaerobic Digestion of Cattle Manure in Brazil.

    Science.gov (United States)

    Resende, Juliana Alves; Godon, Jean-Jacques; Bonnafous, Anaïs; Arcuri, Pedro Braga; Silva, Vânia Lúcia; Otenio, Marcelo Henrique; Diniz, Cláudio Galuppo

    2016-04-01

    Anaerobic digestion is an alternative method for the treatment of animal manure and wastewater. The anaerobic bioconversion of biomass requires a multi-step biological process, including microorganisms with distinct roles. The diversity and composition of microbial structure in pilot-scale anaerobic digestion operating at ambient temperature in Brazil were studied. Influence of the seasonal and temporal patterns on bacterial and archaeal communities were assessed by studying the variations in density, dynamic and diversity and structure. The average daily biogas produced in the summer and winter months was 18.7 and 16 L day(-1), respectively, and there was no difference in the average methane yield. Quantitative PCR analysis revealed that no differences in abundances and dynamics were found for bacterial communities and the total number of Archaea in different seasons. Analysis of bacterial clone libraries revealed a predominance of Firmicutes (54.5 %/summer and 46.7 %/winter) and Bacteroidetes (31.4 %/summer and 44.4 %/winter). Within the Archaea, the phylum Euryarchaeota was predominant in both digesters. Phylogenetic distribution showed changes in percentage between the phyla identified, but no alterations were recorded in the quality and amount of produced methane or community dynamics. The results may suggest that redundancy of microbial groups may have occurred, pointing to a more complex microbial community in the ecosystem related to this ambient temperature system.

  14. Seasonal variation in diet and nutrition of the northern-most population of Rhinopithecus roxellana.

    Science.gov (United States)

    Hou, Rong; He, Shujun; Wu, Fan; Chapman, Colin A; Pan, Ruliang; Garber, Paul A; Guo, Songtao; Li, Baoguo

    2018-04-01

    There is a great deal of spatial and temporal variation in the availability and nutritional quality of foods eaten by animals, particularly in temperate regions where winter brings lengthy periods of leaf and fruit scarcity. We analyzed the availability, dietary composition, and macronutrients of the foods eaten by the northern-most golden snub-nosed monkey (Rhinopithecus roxellana) population in the Qinling Mountains, China to understand food choice in a highly seasonal environment dominated by deciduous trees. During the warm months between April and November, leaves are consumed in proportion to their availability, while during the leaf-scarce months between December and March, bark and leaf/flower buds comprise most of their diet. When leaves dominated their diet, golden snub-nosed monkeys preferentially selected leaves with higher ratios of crude protein to acid detergent fiber. While when leaves were less available, bark and leaf/flower buds that were high in nonstructural carbohydrates and energy, and low in acid detergent fiber were selected. Southern populations of golden snub-nosed monkey can turn to eating lichen, however, the population studied here in this lichen-absent area have adapted to their cool deciduous habitat by instead consuming buds and bark. Carbohydrate and energy rich foods appear to be the critical resources required for the persistence of this species in temperate habitat. The dietary flexibility of these monkeys, both among seasons and populations, likely contributes to their wide distribution over a range of habitats and environments. © 2018 Wiley Periodicals, Inc.

  15. Characterization of black carbon in the ambient air of Agra, India: Seasonal variation and meteorological influence

    Science.gov (United States)

    Gupta, Pratima; Singh, Shalendra Pratap; Jangid, Ashok; Kumar, Ranjit

    2017-09-01

    This study characterizes the black carbon in Agra, India home to the Taj Mahal—and situated in the Indo-Gangetic basin. The mean black carbon concentration is 9.5 μg m-3 and, owing to excessive biomass/fossil fuel combustion and automobile emissions, the concentration varies considerably. Seasonally, the black carbon mass concentration is highest in winter, probably due to the increased fossil fuel consumption for heating and cooking, apart from a low boundary layer. The nocturnal peak rises prominently in winter, when the use of domestic heating is excessive. Meanwhile, the concentration is lowest during the monsoon season because of the turbulent atmospheric conditions and the process of washout by precipitation. The ratio of black carbon to brown carbon is less than unity during the entire study period, except in winter (December). This may be because that biomass combustion and diesel exhaust are major black carbon contributors in this region, while a higher ratio in winter may be due to the increased consumption of fossil fuel and wood for heating purposes. ANOVA reveals significant monthly variation in the concentration of black carbon; plus, it is negatively correlated with wind speed and temperature. A high black carbon mass concentration is observed at moderate (1-2 m s-1) wind speed, as compared to calm or turbulent atmospheric conditions.

  16. Patterns of activity and use of time in rural Bangladesh: class, gender, and seasonal variations.

    Science.gov (United States)

    Zaman, H

    1995-04-01

    Tarapur is a village in the district of Rajshahi, Bangladesh, covering an area of 821.05 acres. 342 households with a total population of 1981 were identified in the village by the 1985 census. The author investigated the use of time during 1984 and 1985 in busy, intermediate, and slack seasons among the village population to examine the variation in time use by gender and social class. Activity patterns were found to vary from one season to another, and also across social classes. The study highlights the need to refine some of the conceptual and methodological issues in the collection of data on women and work. The study also presents useful data on home-based production and market-oriented work. It could be useful to adopt an anthropological approach in order to understand the allocation of time by men and women from the perspective of household production and the local economy and culture. Study findings focus upon the following policy issues: the need for a better understanding and recognition of the significant role of women in field agriculture and postharvest processing, creation of further nontraditional employment and business opportunities for poor women in rural areas, and consciousness-raising and the challenge of cultural barriers affecting women. Rural women, especially those in need of employment and involved in market-oriented production, should be the target of mainstream development activities in future planning.

  17. Seasonal and diurnal variation in concentrations of gaseous and particulate phase endosulfan

    Science.gov (United States)

    Li, Qingbo; Wang, Xianyu; Song, Jing; Sui, Hongqi; Huang, Lei; Li, Lu

    2012-12-01

    Successive 52-week air monitoring of α-endosulfan (α-E), β-endosulfan (β-E) and endosulfan sulfate (E.S) in the gaseous and particulate phases was conducted in Dalian city, northeast China by using an active high-volume sampler. Significant seasonal and diurnal variations in endosulfan concentrations were observed. It was found that the concentration of gaseous-phase α-E peaked in the summer and the concentration of particulate phase α-E peaked in the winter. For E.S, both gaseous and particulate phase concentrations peaked in the summer. α-E was distributed predominantly in the gas phase in the summer but was distributed mainly in the particulate phase in the winter. β-E was distributed mainly in the gas phase in the summer and in the particulate phase at other times of the year. E.S was distributed mainly in the particulate phase throughout the year. Elevated temperatures facilitated the volatilization of α-E from particle surfaces but exerted little effect on β-E and had almost no effect on E.S. Trajectory-based analysis indicates that the seasonal variation in atmospheric concentrations of endosulfan in Dalian city was influenced strongly by the land and sea air masses. In addition, differences in endosulfan concentrations in the particulate phase between day and night were likely due to the circulation of sea/land breezes. The 'cold-condensation' effect occurring during the night may result in the attachment of endosulfan to the particulate phase.

  18. The seasonal variation in skin hydration, sebum, scaliness, brightness and elasticity in Korean females.

    Science.gov (United States)

    Nam, G W; Baek, J H; Koh, J S; Hwang, J-K

    2015-02-01

    Age, gender, regional, and ethnic differences influence skin conditions. The purpose of this study was to observe the effects of environments, especially the air temperature, relative humidity, air pressure, duration of sunshine, and precipitation on skin, and the seasonal variation in skin hydration, sebum, scales, brightness, and elasticity in Korean females. The study included 89 Korean subjects, aged 29.7 ± 6.2 years. The five skin biophysical parameters (skin hydration, sebum, scales, brightness, and elasticity) were measured at six sites: forehead, under the eye, frontal cheek, crow's foot, lateral cheek, and inner forearm. Skin hydration was measured using the Corneometer® CM 825. Skin sebum was measured with Sebumeter® SM 815. Skin scaliness was measured with Visioscan® VC 98. Skin brightness (L* value) was measured by using Spectrophotometer. A suction chamber device, Cutometer® MPA 580, was used to measure the skin elasticity. The measurements were performed every month for 13 months, from April 2007 to April 2008. There were significantly seasonal variations in environmental factors. The air temperature was the lowest in January (-1.7°C), and the highest in August (26.5°C). The relative humidity was the lowest in February (46%), and the highest in July and August (75%). There was a negative correlation between skin scaliness and three environmental factors such as air temperature, relative humidity, and highest precipitation. There was a positive correlation between skin scaliness and two environmental factors such as air pressure and duration of sunshine. Elasticity was correlated with air temperature positively and with air pressure negatively. The correlations shown between the skin biophysical parameters and environmental factors demonstrate that the skin biophysical parameters are affected by environmental factors. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  19. Characterization of road runoff with regard to seasonal variations, particle size distribution and the correlation of fine particles and pollutants.

    Science.gov (United States)

    Hilliges, R; Endres, M; Tiffert, A; Brenner, E; Marks, T

    2017-03-01

    Urban runoff is known to transport a significant pollutant load consisting of e.g. heavy metals, salts and hydrocarbons. Interactions between solid and dissolved compounds, proper understanding of particle size distribution, dissolved pollutant fractions and seasonal variations is crucial for the selection and development of appropriate road runoff treatment devices. Road runoff at an arterial road in Augsburg, Germany, has been studied for 3.5 years. A strong seasonal variation was observed, with increased heavy metal concentrations with doubled and tripled median concentrations for heavy metals during the cold season. Correlation analysis showed that de-icing salt is not the only factor responsible for increased pollutant concentrations in winter. During the cold period, the fraction of dissolved metals was lower compared to the warm season. In road dust, the highest metal concentrations were measured for fine particles. Metals in road runoff were found to show a significant correlation to fine particles SS63 (removal rates.

  20. Organic aerosol source apportionment in London 2013 with ME-2: exploring the solution space with annual and seasonal analysis

    Directory of Open Access Journals (Sweden)

    E. Reyes-Villegas

    2016-12-01

    Full Text Available The multilinear engine (ME-2 factorization tool is being widely used following the recent development of the Source Finder (SoFi interface at the Paul Scherrer Institute. However, the success of this tool, when using the a value approach, largely depends on the inputs (i.e. target profiles applied as well as the experience of the user. A strategy to explore the solution space is proposed, in which the solution that best describes the organic aerosol (OA sources is determined according to the systematic application of predefined statistical tests. This includes trilinear regression, which proves to be a useful tool for comparing different ME-2 solutions. Aerosol Chemical Speciation Monitor (ACSM measurements were carried out at the urban background site of North Kensington, London from March to December 2013, where for the first time the behaviour of OA sources and their possible environmental implications were studied using an ACSM. Five OA sources were identified: biomass burning OA (BBOA, hydrocarbon-like OA (HOA, cooking OA (COA, semivolatile oxygenated OA (SVOOA and low-volatility oxygenated OA (LVOOA. ME-2 analysis of the seasonal data sets (spring, summer and autumn showed a higher variability in the OA sources that was not detected in the combined March–December data set; this variability was explored with the triangle plots f44 : f43 f44 : f60, in which a high variation of SVOOA relative to LVOOA was observed in the f44 : f43 analysis. Hence, it was possible to conclude that, when performing source apportionment to long-term measurements, important information may be lost and this analysis should be done to short periods of time, such as seasonally. Further analysis on the atmospheric implications of these OA sources was carried out, identifying evidence of the possible contribution of heavy-duty diesel vehicles to air pollution during weekdays compared to those fuelled by petrol.

  1. Diurnal and seasonal variations in surface methane at a tropical coastal station: Role of mesoscale meteorology.

    Science.gov (United States)

    Kavitha, M; Nair, Prabha R; Girach, I A; Aneesh, S; Sijikumar, S; Renju, R

    2018-08-01

    In view of the large uncertainties in the methane (CH 4 ) emission estimates and the large spatial gaps in its measurements, studies on near-surface CH 4 on regional basis become highly relevant. This paper presents the first time observational results of a study on the impacts of mesoscale meteorology on the temporal variations of near-surface CH 4 at a tropical coastal station, in India. It is based on the in-situ measurements conducted during January 2014 to August 2016, using an on-line CH 4 analyzer working on the principle of gas chromatography. The diurnal variation shows a daytime low (1898-1925ppbv) and nighttime high (1936-2022ppbv) extending till early morning hours. These changes are closely associated with the mesoscale circulations, namely Sea Breeze (SB) and Land Breeze (LB), as obtained through the meteorological observations, WRF simulations of the circulations and the diurnal variation of boundary layer height as observed by the Microwave Radiometer Profiler. The diurnal enhancement always coincides with the onset of LB. Several cases of different onset timings of LB were examined and results presented. The CH 4 mixing ratio also exhibits significant seasonal patterns being maximum in winter and minimum in pre-monsoon/monsoon with significant inter-annual variations, which is also reflected in diurnal patterns, and are associated with changing synoptic meteorology. This paper also presents an analysis of in-situ measured near-surface CH 4 , column averaged and upper tropospheric CH 4 retrieved by Atmospheric Infrared Sounder (AIRS) onboard Earth Observing System (EOS)/Aqua which gives insight into the vertical distribution of the CH 4 over the location. An attempt is also made to estimate the instantaneous radiative forcing for the measured CH 4 mixing ratio. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Length-Weight Realtionship and Seasonal Distrubition of Magalaspis cordyla (Linnaeus 1758 fish Size frequency Variation from Karachi Coast

    Directory of Open Access Journals (Sweden)

    Quratulan AHMED

    2013-09-01

    Full Text Available The study of seasonal variation in distribution of 167 fishes of magalaspis cordyla from the Karachi fish harbour collected seasonally (pre-monsoon, mon-soon, post-monsoon between September 2011-August 2012. The highest catch of fish (68 was recorded in pre-monsoon season and the lowest catch of fish (47 was recorded in monsoon season. The highest mean length (38.6+ 0.746 and weight (288+ 21.90 was measured during pre-monsoon season and lowest mean length (22.5+ 0.671 and weight (120.5+ 2.73 was measured during mon-soon season. The highest mean condition factor (1.192+ 0.817 and minimum (0.500+ 0.038 was recorded in pre-monsoon season. Fish estimated negative and positive allometric growth because b values larger and less then 3 in pre-monsoon and monsoon season but post-monsoon season showed positive allometric growth because b value larger then 3 in all size classes

  3. The activity of glutathione S-transferase in hepatopancreas of Procambarus clarkii: seasonal variations and the influence of environmental pollutants.

    Science.gov (United States)

    Nies, E; Almar, M M; Hermenegildo, C; Monsalve, E; Romero, F J

    1991-01-01

    1. The glutathione S-transferase activity in hepatopancreas of the American red crayfish Procambarus clarkii after 15 days' acclimatization in tap water aquaria was measured in specimens collected monthly for a whole year, and shows seasonal variation. 2. Previous data on the environmental pollution of Lake Albufera suggest a possible correlation with the activity tested in the different seasons of the year considering the results of non-acclimatized animals.

  4. Seasonal variation in Eurasian Wigeon Anas penelope sex and age ratios from hunter-based surveys

    DEFF Research Database (Denmark)

    Clausen, Kevin Kuhlmann; Dalby, Lars; Sunde, Peter

    2013-01-01

    dominated by adult males, and juvenile proportions were highest in November and significantly lower before and after this peak. Nationwide field assessments undertaken in January 2012 showed no significant differences from sex and age ratios in the wing survey data from that particular hunting season (2011...... schemes. This study found consistent seasonal variation in Eurasian Wigeon Anas penelope sex and age ratios among Danish hunter-based wing surveys, and describes how accounting for this variation might explain reported discrepancies between this and other monitoring methods. Early season flocks were....../2012), indicating that this survey is a good predictor of Wigeon demography. These results highlight the need to account for consistent temporal variation in such demographic time series when using the results to model population parameters....

  5. The seasonal variation of water vapor and ozone in the upper mesosphere - Implications for vertical transport and ozone photochemistry

    Science.gov (United States)

    Bevilacqua, Richard M.; Summers, Michael E.; Strobel, Darrell F.; Olivero, John J.; Allen, Mark

    1990-01-01

    This paper reviews the data base supplied by ground-based microwave measurements of water vapor in the mesosphere obtained in three separate experiments over an eight-year period. These measurements indicate that the seasonal variation of water vapor in the mesosphere is dominated by an annual component with low values in winter and high values in summer, suggesting that the seasonal variation of water vapor in the mesosphere (below 80 km) is controlled by advective rather than diffusive processes. Both the seasonal variation and the absolute magnitude of the water vapor mixing ratios obtained in microwave measurements were corroborated by measurements obtained in the Spacelab GRILLE and ATMOS experiments, and were found to be consistent with several recent mesospheric dynamics studies.

  6. Seasonal variations in physical characteristics of aerosol particles at the King Sejong Station, Antarctic Peninsula

    Science.gov (United States)

    Kim, Jaeseok; Yoon, Young Jun; Gim, Yeontae; Kang, Hyo Jin; Choi, Jin Hee; Park, Ki-Tae; Lee, Bang Yong

    2017-11-01

    Seasonal variability in the physical characteristics of aerosol particles sampled from the King Sejong Station in the Antarctic Peninsula was investigated over the period between March 2009 and February 2015. Clear seasonal cycles for the total particle concentration (CN) were observed. The mean monthly concentration of particles larger than 2.5 nm (CN2.5) was highest during the austral summer, with an average value of 1080.39 ± 595.05 cm-3, and lowest during the austral winter, with a mean value of 197.26 ± 71.71 cm-3. The seasonal patterns in the concentrations of cloud condensation nuclei (CCN) and CN coincide, with both concentrations being at a minimum in winter and maximum in summer. The measured CCN spectra were approximated by fitting a power-law function relating the number of CCN for a given supersaturation (SS) to each SS value, with fitting coefficients C and kT. The values for C varied from 6.35 to 837.24 cm-3, with a mean of 171.48 ± 62.00 cm-3. The values for kT ranged from 0.07 to 2.19, with a mean of 0.41 ± 0.10. In particular, the kT values during the austral summer were higher than those during the winter, indicating that aerosol particles are more sensitive to SS changes during summer. Furthermore, the annual mean hygroscopicity parameter, κ, was estimated as 0.15 ± 0.05, for a SS of 0.4 %. The effects of the origin and pathway travelled by the air mass on the physical characteristics of the aerosol particles were also determined. The modal diameter of aerosol particles originating in the South Pacific Ocean showed a seasonal variation varying from 0.023 µm in winter to 0.034 µm in summer for the Aitken mode, and from 0.086 µm in winter to 0.109 µm in summer for the accumulation mode.

  7. Seasonal variations in physical characteristics of aerosol particles at the King Sejong Station, Antarctic Peninsula

    Directory of Open Access Journals (Sweden)

    J. Kim

    2017-11-01

    Full Text Available Seasonal variability in the physical characteristics of aerosol particles sampled from the King Sejong Station in the Antarctic Peninsula was investigated over the period between March 2009 and February 2015. Clear seasonal cycles for the total particle concentration (CN were observed. The mean monthly concentration of particles larger than 2.5 nm (CN2.5 was highest during the austral summer, with an average value of 1080.39 ± 595.05 cm−3, and lowest during the austral winter, with a mean value of 197.26 ± 71.71 cm−3. The seasonal patterns in the concentrations of cloud condensation nuclei (CCN and CN coincide, with both concentrations being at a minimum in winter and maximum in summer. The measured CCN spectra were approximated by fitting a power-law function relating the number of CCN for a given supersaturation (SS to each SS value, with fitting coefficients C and kT. The values for C varied from 6.35 to 837.24 cm−3, with a mean of 171.48 ± 62.00 cm−3. The values for kT ranged from 0.07 to 2.19, with a mean of 0.41 ± 0.10. In particular, the kT values during the austral summer were higher than those during the winter, indicating that aerosol particles are more sensitive to SS changes during summer. Furthermore, the annual mean hygroscopicity parameter, κ, was estimated as 0.15 ± 0.05, for a SS of 0.4 %. The effects of the origin and pathway travelled by the air mass on the physical characteristics of the aerosol particles were also determined. The modal diameter of aerosol particles originating in the South Pacific Ocean showed a seasonal variation varying from 0.023 µm in winter to 0.034 µm in summer for the Aitken mode, and from 0.086 µm in winter to 0.109 µm in summer for the accumulation mode.

  8. Seasonal and latitudinal variations of surface fluxes at two Arctic terrestrial sites

    Science.gov (United States)

    Grachev, Andrey A.; Persson, P. Ola G.; Uttal, Taneil; Akish, Elena A.; Cox, Christopher J.; Morris, Sara M.; Fairall, Christopher W.; Stone, Robert S.; Lesins, Glen; Makshtas, Alexander P.; Repina, Irina A.

    2017-11-01

    This observational study compares seasonal variations of surface fluxes (turbulent, radiative, and soil heat) and other ancillary atmospheric/surface/permafrost data based on in-situ measurements made at terrestrial research observatories located near the coast of the Arctic Ocean. Hourly-averaged multiyear data sets collected at Eureka (Nunavut, Canada) and Tiksi (East Siberia, Russia) are analyzed in more detail to elucidate similarities and differences in the seasonal cycles at these two Arctic stations, which are situated at significantly different latitudes (80.0°N and 71.6°N, respectively). While significant gross similarities exist in the annual cycles of various meteorological parameters and fluxes, the differences in latitude, local topography, cloud cover, snowfall, and soil characteristics produce noticeable differences in fluxes and in the structures of the atmospheric boundary layer and upper soil temperature profiles. An important factor is that even though higher latitude sites (in this case Eureka) generally receive less annual incoming solar radiation but more total daily incoming solar radiation throughout the summer months than lower latitude sites (in this case Tiksi). This leads to a counter-intuitive state where the average active layer (or thaw line) is deeper and the topsoil temperature in midsummer are higher in Eureka which is located almost 10° north of Tiksi. The study further highlights the differences in the seasonal and latitudinal variations of the incoming shortwave and net radiation as well as the moderating cloudiness effects that lead to temporal and spatial differences in the structure of the atmospheric boundary layer and the uppermost ground layer. Specifically the warm season (Arctic summer) is shorter and mid-summer amplitude of the surface fluxes near solar noon is generally less in Eureka than in Tiksi. During the dark Polar night and cold seasons (Arctic winter) when the ground is covered with snow and air temperatures

  9. Seasonal variation of low-latitude E-region plasma irregularities studied using Gadanki radar and ionosonde

    Directory of Open Access Journals (Sweden)

    D. V. Phanikumar

    2008-07-01

    Full Text Available In this paper, we present seasonal variation of E region field-aligned irregularities (FAIs observed using the Gadanki radar and compare them with the seasonal variation of Es observed from a nearby location SHAR. During daytime, FAIs occur maximum in summer and throughout the day, as compared to other seasons. During nighttime, FAIs occur equally in both summer and winter, and relatively less in equinoxes. Seasonal variations of Es (i.e. ftEs and fbEs show that the daytime activity is maximum in summer and the nighttime activity is maximum in equinoxes. No relation is found between FAIs occurrence/SNR and ftEs/fbEs. FAIs occurrence, however, is found to be related well with (ftEs−fbEs. This aspect is discussed in the light of the present understanding of the mid-latitude Es-FAIs relationship. The seasonal variations of FAIs observed at Gadanki are compared in detail with those of Piura, which show a significant difference in the daytime observations. The observed difference has been discussed considering the factors governing the generation of FAIs.

  10. Seasonal variation of low-latitude E-region plasma irregularities studied using Gadanki radar and ionosonde

    Directory of Open Access Journals (Sweden)

    D. V. Phanikumar

    2008-07-01

    Full Text Available In this paper, we present seasonal variation of E region field-aligned irregularities (FAIs observed using the Gadanki radar and compare them with the seasonal variation of Es observed from a nearby location SHAR. During daytime, FAIs occur maximum in summer and throughout the day, as compared to other seasons. During nighttime, FAIs occur equally in both summer and winter, and relatively less in equinoxes. Seasonal variations of Es (i.e. ftEs and fbEs show that the daytime activity is maximum in summer and the nighttime activity is maximum in equinoxes. No relation is found between FAIs occurrence/SNR and ftEs/fbEs. FAIs occurrence, however, is found to be related well with (ftEs−fbEs. This aspect is discussed in the light of the present understanding of the mid-latitude Es-FAIs relationship. The seasonal variations of FAIs observed at Gadanki are compared in detail with those of Piura, which show a significant difference in the daytime observations. The observed difference has been discussed considering the factors governing the generation of FAIs.

  11. Seasonal Variation in Solar Ultra Violet Radiation and Early Mortality in Extremely Preterm Infants.

    Science.gov (United States)

    Salas, Ariel A; Smith, Kelly A; Rodger