Pattern Of Seasonal Fluctuations Research Articles

Relationship between Dehydrins and Adaptation of Cajander Larch to Yakutia Cryolithozone Conditions

Composition and seasonal fluctuations of stress dehydrin proteins of Cajander larch (Larix cajanderi Mayr) growing under extremely cold climatic conditions in Central Yakutia, which are notable for an extraordinary frost resistance, were investigated. Immunoblotting technique made it possible to detect major dehydrins in a molecular mass range of 17–20, 37–42, and 73 kD in the shoots of L. cajanderi for the first time. A high level of polymorphism of dehydrins within a population of L. cajanderi was detected and differences between the examined specimens of trees were mainly revealed in a molecular mass range of 20–37 kD. Within the circannual cycle of larch, the greatest seasonal fluctuations were observed in low-molecular dehydrins, with their content rising at the end of phenological autumn and reaching a steady level in the period of ultralow winter temperatures. The pattern of seasonal fluctuations and wide variety of dehydrins in larch shoots may point to their possible participation in the formation of a unique frost resistance of L. cajanderi upon adaptation of this conifer species to conditions existing in the cryolithozone.

Seasonal variations of airborne phthalates and novel non-phthalate plasticizers in a test residence in cold regions: Effects of temperature, humidity, total suspended particulate matter, and sources

As a class of plasticizers widely used in consumer products, some phthalate esters (PAEs) have been restricted due to their adverse health effects and ubiquitous presence, leading to the introduction of alternative non-phthalates plasticizers (NPPs) to the market. However, few studies focus on the influence of environmental parameters on the presence of these plasticizers and the potential human health risks for people living in poorly ventilated indoor spaces in cold regions. We investigated the trends of PAEs and NPPs in air in a typical indoor residence in northern China for over one year. The air concentrations of PAEs were significantly higher than those of NPPs (p < 0.05), indicating that PAEs are still the dominant plasticizers currently being used in the studied residence. PAEs showed seasonal fluctuation patterns of the highest levels found in summer and autumn. The temperature and relative humidity dependence for most PAEs and NPPs decreased with decreasing vapor pressure. Concentrations of the high molecular weight NPPs and PAEs positively correlated with total suspended particles (TSP). It is worth noting that the peak concentrations of PAEs and NPPs were found when the haze occurred in autumn. Principal component analysis (PCA) suggested the diverse applications of PAEs and NPPs in the indoor environment. The hazard index (HI) values observed in this study were all below international guidelines (<1); however, the average carcinogenic risk (CR) values for some compounds exceeded acceptable levels (One in a million), which raised concerns about the possibility of carcinogenicity for people living indoors for long periods of time in cold regions.

Infestation and Seasonal Fluctuation of Gamasid Mites (Parasitiformes: Gamasida) on Indochinese Forest Rat, Rattus andamanensis (Rodentia: Muridae) in Southern Yunnan of China.

Simple SummaryGamasid mites are a large group of arthropods and some of them are ectoparasites on the body surface of rodents and some other small mammals. Some species of ectoparasitic gamasid mites are associated with the transmission of some zoonotic diseases such as rickettsialpox and hemorrhagic fever with renal syndrome (HFRS). Based on a 12-month consecutive investigation at Jingha village in southern Yunnan of China from April 2016 to March 2017, the present paper studied the infestation and seasonal fluctuation of gamasid mites on the Indochinese forest rat, Rattus andamanensis, the most dominant species of rodent at the investigated site. The temperature and rainfall are two key factors that influence the seasonal fluctuation of the mites.A 12-month consecutive investigation was made at Jingha village in southern Yunnan of southwest China from April 2016 to March 2017. A total of 2053 Indochinese forest rats (Rattus andamanensis Blyth, 1860) were captured and examined, which account for 84.69% (2053/2424) of all the animal hosts (rodents and other small mammals) at the investigation site. And 39.82% (13,531/33,980) of gamasid mites were identified from the body surface of R. andamanensis and they belong to 41 species, 10 genera, 3 subfamilies and 2 families. Of the 41 species of gamasid mites identified from R. andamanensis, Laelaps nuttalli Hirst, 1915 and Laelaps echidninus Berlese, 1887 were the most dominant with 70.63% and 20.67% of constituent ratios respectively. In monthly fluctuations of all the gamasid mites on R. andamanensis, the constituent ratio (Cr) and overall infestation mean abundance (MA) of the mites in 12 months showed two obvious peaks in January (winter season) and June (summer season). However, the two dominant mite species, L. nuttalli and L. echidninus, showed different patterns of seasonal fluctuations. Laelaps nuttalli occurred throughout the year, and its Cr and MA showed two prominent peaks in winter season (December and January) and summer season (June), which belongs to the summer-winter type of seasonal fluctuation. Laelaps echidninus also occurred on R. andamanensis throughout the year, but its Cr and MA showed only one peak in winter season (December and January), which belongs to the winter type of seasonal fluctuation. A negative correlation existed between two climatic factors (temperature and rainfall) and the infestations (Cr, prevalence PM and MA) of two dominant mite species (L. nuttalli and L. echidninus) on R. andamanensis (p < 0.05). Temperature and rainfall are considered to be two key factors that influence the seasonal fluctuations of the mites on the studied rat species.

Malian adults maintain serologic responses to virulent PfEMP1s amid seasonal patterns of fluctuation

Plasmodium falciparum erythrocyte membrane protein-1s (PfEMP1s), diverse malaria proteins expressed on the infected erythrocyte surface, play an important role in pathogenesis, mediating adhesion to host vascular endothelium. Antibodies to particular non-CD36-binding PfEMP1s are associated with protection against severe disease. We hypothesized that given lifelong P. falciparum exposure, Malian adults would have broad PfEMP1 serorecognition and high seroreactivity levels during follow-up, particularly to non-CD36-binding PfEMP1s such as those that attach to endothelial protein C receptor (EPCR) and intercellular adhesion molecule-1 (ICAM-1). Using a protein microarray, we determined serologic responses to 166 reference PfEMP1 fragments during a dry and subsequent malaria transmission season in Malian adults. Malian adult sera had PfEMP1 serologic responses throughout the year, with decreased reactivity to a small subset of PfEMP1 fragments during the dry season and increases in reactivity to a different subset of PfEMP1 fragments during the subsequent peak malaria transmission season, especially for intracellular PfEMP1 domains. For some individuals, PfEMP1 serologic responses increased after the dry season, suggesting antigenic switching during asymptomatic infection. Adults were more likely to experience variable serorecognition of CD36-binding PfEMP1s than non-CD36-binding PfEMP1s that bind EPCR or ICAM-1, which remained serorecognized throughout the year. Sustained seroreactivity to non-CD36-binding PfEMP1s throughout adulthood amid seasonal fluctuation patterns may reflect underlying protective severe malaria immunity and merits further investigation.

Seasonality in tourist flows: Decomposing and testing changes in seasonal concentration

Abstract This paper shows that changes in timing and magnitude of seasonality in tourist flows can be measured by decomposing the change in the Gini index, a widely used index of seasonal concentration, into two components. One of them tracks the change in the pattern of seasonal fluctuations and the second captures the change in their magnitude. To assess whether changes in the seasonal pattern and magnitude are significant, a technique for testing hypotheses concerning the two components is developed. We examine changes in the seasonal concentration of tourist arrivals in six tourist destinations in the Veneto Region, one of the most tourism-oriented regions in Europe, from 2006 to 2016. The magnitude of seasonality significantly decreased in some destinations with a diversified tourism product, such as Euganean Spas and Lake Garda. The seasonal pattern remained substantially stable for all destinations except Venice, where a non-negligible shift in the seasonal pattern occurred.

Longitudinal study of northern fur seal (&lt;i&gt;Callorhinus ursinus&lt;/i&gt;) hematology

Although the causes have not been specified yet, wild populations of northern fur seals (Callorhinus ursinus) have been decreasing, which is why conservation techniques such as captive breeding and health maintenance should be established. Hematological parameters can be used to maintain the health status of northern fur seals kept in captivity for artificial reproduction and public education. Year-round fluctuations of blood parameters have not been examined for northern fur seals due to the difficulties in obtaining serial blood samples from wild animals during the oceanic migration period from late autumn to spring. In this study, blood samples were collected from four captive northern fur seals and analyzed monthly for more than three years to clarify the seasonal fluctuation patterns in 14 hematological parameters. Many hematological parameters seemed to be seasonal patterns: summer–autumn and winter–spring; leukocyte-related parameters were higher in summer and autumn than in winter and spring; erythrocyte-related parameters were lower in summer and autumn than in winter and spring. Significant seasonal differences in nine of the 14 parameters were observed using a generalized linear mixed model (GLMM) analysis. These results have improved our understanding of the seasonal patterns of hematological characteristics in the northern fur seal and can contribute to the health care of protected or captive northern fur seals.

An improved seasonal GM(1,1) model based on the HP filter for forecasting wind power generation in China

With rapid development of wind power in China, it has become an integral part of the energy structure, so it is of practical significance to forecast wind power generation accurately. As wind power generation in China experiences both an exponential increase trend and a seasonal fluctuation pattern, it cannot be accurately forecasted by traditional models. As the grey model GM(1,1) can capture an exponential growth trend and the Hodrick-Prescott filter is known for its capability of characterizing seasonality factors, this paper proposes a novel seasonal forecasting method that integrates the HP filter into the grey model GM(1,1). The proposed model is then applied to carry out an empirical analysis based on the seasonal wind power generation data between 2013 and 2019 in China. The forecasting results from the new model are then compared with three existing approaches. The comparison results indicate that the proposed model generally outperforms existing methods as it can well capture seasonal fluctuations in the data series. A further prediction of wind power generation in China is conducted into a future horizon of 2020 and 2021 by using our model, followed by a set of policy recommendations for further development of the wind power industry in China.

First report of saxitoxins and anatoxin-a production by cyanobacteria from Lithuanian lakes

ABSTRACT This study describes the first report on saxitoxins (STXs) and anatoxin-a (ANTX-a) production by cyanobacteria in Lithuanian lakes. Seasonal fluctuation patterns for neurotoxins were determined in samples collected from eutrophic lakes during July–September. Strains of Aphanizomenon gracile, A. flos-aquae, Cuspidothrix issatschenkoi, Sphaerospermopsis aphanizomenoides and Anabaenopsis cf. elenkinii were also isolated from the lakes and screened for the occurrence of neurotoxic STXs, ANTX-a and for the cytotoxin cylindrospermopsin (CYN). The highest concentration of STX (up to 1.06 µg l–1 in Lake Jieznas) was detected during July‒August and coincided with a predominance of A. gracile in the phytoplankton. Of the isolated strains, only A. gracile was confirmed to be a producer of STXs by chemical (LC-MS/MS) and genetic (sxtA) methods. Sequencing of the phycocyanin intergenic spacer and flanking regions (cpcBA) revealed that A. gracile formed a genetically homogenous group. Only trace amounts of ANTX-a were detected in field samples (up to 0.31 µg l–1 in Lake Širvys). CYN was detected in neither the bloom samples nor in the isolated strains.

Seasonal Fluctuation of Polycyclic Aromatic Hydrocarbons and Aerosol Genotoxicity in Long-Range Transported Air Mass Observed at the Western End of Japan

In order to clarify the level transboundary air pollution caused by polycyclic aromatic hydrocarbons (PAHs) and genotoxic substances, aerosols were collected from forest and suburban sites in Nagasaki, west Japan, for 6 years. The PAH concentration was measured, and the genotoxicity of the substances were evaluated using the umu test. The results showed no notable trends in the concentration or toxicity of either sites throughout the study period. The suburban and forest sites shared similar seasonal fluctuation patterns and quantitative values, suggesting that the western end of Japan might be affected by long-range transported pollutants, especially in winter. PAH concentration and genotoxicity showed the same seasonal patterns of increased levels in winter and lower levels in summer. This suggests that PAHs and genotoxic substances were correlated and share common sources. Back trajectory and source analyses were conducted using the diagnostic ratios of PAHs. It was predicted that air pollution by PAHs at the forest site arise predominantly as a result of biomass or coal combustion in continental regions, such as northern parts of China and the Korean Peninsula. This is particularly expected in winter. Therefore, genotoxic substances would also be strongly influenced by transboundary pollution from the continental region. In addition, it was estimated that the contribution of transboundary PAH pollution could reach 70% at the suburban site in winter.

Changes in seasonality of births in Poland in the years 1900–2009

Background: To date, several countries have documented changes over time in the pattern of seasonal fluctuations of births. Differences in these changes between countries allow us to better understand the social and economic factors determining birth seasonality. Objective: The aim of the present study is to explore birth seasonality in Poland over a period of 110 years. Methods: The study was conducted using the birth dates of 48,090,100 Polish citizens born in the years 1900–2009 and registered in the General Electronic System for Registration of the Population. I transformed the data into monthly time series of births, normalized the monthly birth rates for the unequal duration of months and years, and detrended by taking them to the centred 12-month average. Finally, I estimated seasonality patterns for particular decades by means of least squares regression on the harmonic model. Results: As many as three, relatively stable seasonal birth patterns occurred in Poland in the studied period. In 20th century Europe, the first one (1900–1919), characterised by a minimum birth rate in June, had previously only been observed in Italy. The second pattern with the spring peak and local peak in September remained almost unchanged in Poland for the longest time (1950–1979). Then, within a decade, it transformed into a new, third pattern (1990–2009), with peaks in July and September. Contribution: This article is the first to document in detail the changes in birth seasonality in Poland over a period of 110 years.

Epidemiological characteristics of pulmonary tuberculosis in mainland China from 2004 to 2015: a model-based analysis

BackgroundWe used data released by the government to analyze the epidemiological distribution of pulmonary tuberculosis in mainland China from 2004 to 2015, in order to provide a deeper understanding of trends in the epidemiology of pulmonary tuberculosis in China and a theoretical basis to assess the effectiveness of government interventions and develop more targeted prevention and control strategies.MethodsA discrete dynamic model was designed based on the epidemiological characteristics of pulmonary tuberculosis and fitted to data published by the government to estimate changes in indicators such as adequate contact rate, prevalence of non-treated pulmonary tuberculosis (abbreviated as prevalence), and infection rate. Finally, we performed sensitivity analyses of the effects of parameters on the population infection rate.ResultsThe epidemiological features of pulmonary tuberculosis in China include a pattern of seasonal fluctuations, with the highest rates of infection in autumn and winter. The adequate contact rate has increased slightly from an average of 0.12/month in 2010 to an average of 0.21/month in 2015. The prevalence in the population has continued to decrease from 3.4% in early 2004 to 1.7% in late 2015. The Mycobacterium tuberculosis (M. tuberculosis) infection rate in the population decreased gradually from 42.3% at the beginning of 2004 to 36.7% at the end of 2015. The actual number of new infections gradually decreased from 1,300,000/year in 2010 to 1,100,000/year in 2015. The actual number of new patients each year has been relatively stable since 2010 and remains at approximately 2,600,000/year.ConclusionsThe population prevalence and the M. tuberculosis infection rate have decreased year by year since 2004, indicating that the tuberculosis epidemic in China has been effectively controlled. However, pulmonary tuberculosis has become increasingly contagious since 2010. China should focus on the prevention and control of pulmonary tuberculosis during autumn and winter.

Predicting Geographic Distribution of Forensically Significant Blow Flies of Subfamily Chrysomyinae (Diptera: Calliphoridae) in Northern Thailand.

Blow flies (Diptera: Calliphoridae) are carrion-breeding flies that are commonly used as evidence in forensic investigation. An adequate knowledge of ecological and geographical data of blow fly has a direct application in forensic science, as far as estimating time of colonization or corpse relocation. The aim of this study was to evaluate the occurrence of four species of Chrysomyinae (Chrysomya pinguis, Chrysomya chani, Chrysomya villeneuvi, and Ceylonomyia nigripes) across six land use types in central Chiang Mai, northern Thailand. Eighteen study sites were selected for sampling across three districts of Chiang Mai province (Mueang Chiang Mai, Mae Rim, and Hang Dong). Adult flies were collected every two weeks using a funnel trap baited with 1-day tainted beef offal. The predicted geographic distributions of forensically important blow fly species were modeled using the computer program ArcGIS, based on selected climatic variables (temperature, relative humidity, and light intensity) recorded at study sites. During the study period, 1298 adult flies were collected, with peak fly occurrence during summer (April–May). Seasonal fluctuation patterns varied depending on fly species. Climatic factors displayed diverse impact on associated fly populations. Identified species were restricted mainly to mixed deciduous forests (MDF) especially in the mountainous area. None of these flies were trapped in an urban area.

OCEANOGRAPHIC OBSERVATIONS IN THE LAGOON OF KAIAFA (W PELOPONNESE)

The Kaifa lagoon is a coastal marine ecosystem located in the Kyparisiakos Bay. The purpose of this study is to: (a) To determine the spatial and temporal changes of the physicochemical parameters in the water column of the Kaifa lagoon and (b). To create a base of information for future use for the restoration of the lagoon. Temperature, salinity, pH and dissolved oxygen were measured insitu in 28 stations. Furthermore, water samples were taken for the determination of NO2, NO3, NH4 and PO4 on seasonal bnsin from November '94 to September '95. The temperature was fluctuating from 15,90 °C in March to 30,41 °C in late August and late September. Further the seasonal variation of the temperature showed the expected two thermal periods. The first period is a hot period showing a continuous increase of temperature from March to September. The second period is a cold period showing a continuous decrease of temperature from the September to March. For each period of sampling the temperature of lagoonal water in all the extent of the lagoon remains practically constant because the fluctuation of temperature is very small each time. The salinity varied between 7,2%o and 9,20%o. The salinity like the temperature presented seasonal fluctuation patterns but the lagoon is brackish all the year round. The spatial changes of salinity were absent for every sampling period. The pH values ranged from 6,70 to 8,40. So, the pH values fluctuated in the normal levels for aquatic animals. Further, these are relatively high in spring (arithmetic mean=7.8) owing probably to higher photosynthesis rate. Dissolved oxygen ranges from 3,30 mg/l to 10,00 mg/l. In the sampling periods of September and November the oxygen values were less than 7,00mg/l for a large part of the lagoon except southern margins. This evidence suggests dangerous conditions for the fish life. Phosphate concentrations were low (0,010 mg/l - 0,07 mg/l), in November. On the contrary the phosphate levels were high (on the average 0,111 mg/l) in the sampling period of September and in particular in the southern part of the lagoon. So, this part indicated photosynthetic activity. Further, In March the phosphate concentrations have an intermediate value for every sampling station in relation to the other sampling periods. Ammonia concentrations were considered high (0,24 mg/l - 2,68 mg/l) all the year round. Nitrate levels fluctuated around normal values (0,018 mg/l -0,11mg/l) during the year. The high amount of the ammonia nitrite and nitrate in November suggests the pollution of lagoon from the fertilizers into lagoon through two drainage canals. Nitrite concentrations were high during the cold period (0,041 mg/l - 0,280 mg/l). The spatial and temporal variability of the abiotic parameters of the lagoonal water must be attributed mainly to the strong influence of fresh water witch is discharged into the lagoon from a adjacent karst with hot springs.

Habitat selection of intertidal caprellid amphipods in a changing scenario

Habitat selection is a complex process, dependent on numerous fluctuating conditions and key to species coexistence. In a changing global scenario, it will greatly determine the fate of marine organisms and hence is an important subject to be explored. The present study evaluates host specificity of two caprellid amphipod species, Caprella grandimana and Caprella takeuchii, dwelling on a rocky intertidal where the calcifying macroalgae Jania rubens and Ellisolandia elongata show opposite seasonal fluctuation patterns throughout the year. To avoid confounding preference with other factors, the substrate selection experimental design included both multiple choice and non-choice treatments. Macroalgal structure analyses using fractals and interstitial space index were included in the study, as substrate complexity is a main factor driving preference for epifauna. Caprella grandimana actively selected J. rubens, whereas C. takeuchii did not show any preference; both behaviours remaining consistent regardless of the original substrate. Preference for J. rubens is probably owed to its interstitial space and thalli characteristics, as the complexity analysis suggested, since these allow for better refuge against predators and a more suitable surface for grasping. Meanwhile, the plasticity of C. takeuchii seems to favor an ongoing taking over of its congener at the time of the year when J. rubens drops. We highlight the need for rigor when performing substrate selection experiments; the importance of including habitat selection lessons in conservation strategies and modelling studies dealing with global change; and the risk in generalizing results within the family or genus level, which is occasionally inadequate for understanding the functioning of the ecosystem as a whole.

The relation of vitamin D, metabolic risk and negative symptom severity in people with psychotic disorders

People with psychotic disorders have an increased metabolic risk and their mean life expectancy is reduced with circa 28 years (Olfson et al., 2015).Predictors of this increased metabolic risk are genetic predisposition (Liu et al., 2013), lifestyle factors such as unhealthy diet, physical inactivity and smoking (Bobes et al., 2010), and the side effects of antipsychotic medication (Werner and Covenas, 2014;Chadda et al., 2013). Low vitamin D status might also contribute to an increased metabolic risk (Ginde et al., 2009;Kendrick et al., 2009;Kilkkinen et al., 2009;Ford et al., 2009) and all-cause mortality by promoting atherosclerosis, hypertension, inflammation and activation of the renin-angiotensin system (Wang et al., 2012;Garland et al., 2014;Lee et al., 2008). Also, one review demonstrated cardiovascular mortality rates in the general population were higher during winter than in summer (Zittermann et al., 2005). Vitamin D interacts with dopaminergic, cholinergic and noradrenergic neurotransmitter systems, which have all been implicated in Schizophrenia Research 195 (2018) 513–518 ⁎ Corresponding author at: University Medical Center Groningen, University Center for Psychiatry, Rob Giel Research center, P.O. Box 30.001 (CC72), 9700 RB Groningen, The Netherlands. E-mail addresses: j.bruins@lentis.nl (J. Bruins), f.jorg@umcg.nl (F. Jorg), e.r.v.d.heuvel@tue.nl (E.R. van den Heuvel), a.a.bartels@umcg.nl (A.A. Bartels-Velthuis), e.corpeleijn@umcg.nl (E. Corpeleijn), f.a.j.muskiet@umcg.nl (F.A.J. Muskiet), g.h.m.pijnenborg@rug.nl (G.H.M. Pijnenborg), r.bruggeman@umcg.nl (R. Bruggeman). experiencing psychotic symptoms (Eyles et al., 2013). When vitamin D is low, dopamine signalling in the brain appears to decrease (Eyles et al., 2013;Cui et al., 2015;Cui et al., 2013;Groves et al., 2014), which in its turn could lead to more severe negative symptoms of psychosis (Buchanan et al., 2007). Indeed, several studies found that vitamin D insufficiency was strongly associated with negative symptoms of psychosis (Graham et al., 2015;Yuksel et al., 2014;Cieslak et al., 2014;Ottesen Berg et al., 2010). Vitamin D is thus associated with both metabolic risk and negative symptom severity. Negative symptoms have also been shown to interfere with patients' ability to be physically active and make healthy lifestyle choices, which can increase their metabolic risk (Bergqvist et al., 2013). Negative symptom severity may therefore mediate the association between low vitamin D and increased metabolic risk in people with a psychotic disorder. Vitamin D is mostly produced in the skin by exposure to ultravioletB radiation in sunlight (Brown et al., 1999;Holick, 2007). Absorption of vitamin D and levels of circulation differ among individuals and can be influenced by determinants such as latitude, season, time of day, skin color (Holick et al., 2011), bodyweight, age, calcium intake (Zittermann et al., 2014), diet and genetics (Mazahery and von Hurst, 2015). Vitamin D shows a natural fluctuation throughout the year, with vitamin D insufficiency more likely to occur during winter than in summer (Rosecrans and Dohnal, 2014). A recent study suggests seasonality may also affect clinical symptoms of schizophrenia, although the underlying mechanism is unknown (Byrne et al., 2015). In this study we aim to investigate whether vitamin D levels are associated with metabolic risk in people with psychotic disorders and whether this effect was mediated by negative symptoms. We hypothesize that vitamin D levels may influence the severity of metabolic disturbances and negative symptoms. As vitamin D levels naturally fluctuate throughout the seasons (Rosecrans and Dohnal, 2014), we examine whether metabolic risk and negative symptom severity follow a similar seasonal fluctuation pattern. Furthermore, we investigate whether the http://dx.doi.org/10.1016/j.schres.2017.08.059 0920-9964/© 2017 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Schizophrenia Research journal homepage: www.elsevier.com/locate/schres severity of metabolic risk and negative symptoms differ between patients using and patients not using vitamin D supplementation. In this cross-sectional study, seasonal patterns and differences with regard to supplementation may indicate an interdependent and potentially causal connection between vitamin D, metabolic risk and negative symptom severity

Seasonal Nearshore Occurrence of the Neurotoxin β N methylamino L alanine (BMAA) in Lake Winnipeg, Canada

Seasonal fluctuation patterns of the neurotoxic amino acid β N methylamino L alanine (BMAA) were examined at four-day intervals during the ice-free season in water at three nearshore stations in the south basin of Lake Winnipeg, Canada. BMAA patterns were significantly exponentially correlated with concurrent phaeophytin, and inversely with chlorophyll a, indicating that free BMAA concentrations increased as blooms declined. BMAA was also significantly related to preceding microcystin concentrations, and as chlorophyll a declined, the proportion of BMAA relative to microcystin increased. Cross correlations identified significant relationships between BMAA and immediately preceding nitrate-N/inorganic phosphorus ratios, nitrate-N, rainfall, and a marginal inverse correlation with inorganic phosphorus. Total suspended solids levels were also significantly associated with BMAA, likely due to shading effects. A very high BMAA concentration was found under collapse of intense bloom conditions. These results have implications for water quality monitoring, nutrient management strategies and public health.

Disentangling long- and short-term changes in perennial organ functions in seasonal environments: A model of foliar chlorophyll and nitrogen in saplings of four evergreen broad-leaved trees

Perennial organ functions of trees living in seasonal environments exhibit temporal changes that can be classified as long-term interannual changes and seasonal fluctuations within single years. However, few studies have separately quantified these changes from longitudinal measurement data or analyzed the relationships between them. We developed a hierarchical Bayesian statistical model consisting of three parts: a long-term interannual change expressed by consecutive annual linear trends, seasonal fluctuations with 26 values for two-week periods in a year, and a random effect for repeated measurements. The model can extract long-term interannual changes and seasonal fluctuations from longitudinal repeated measure data. The pattern of seasonal fluctuation, the amount of seasonal fluctuation, and the net annual change are expressed by the estimated model parameters. We applied our model to foliar chlorophyll (Chl) and nitrogen (N) content measured repeatedly on more than 1-year-old leaves of saplings in four evergreen broad-leaved tree species using nondestructive optical methods. The model successfully explained large variations in the Chl and N content. In general, seasonal fluctuations corresponded to the phenology of current-year leaves; Chl and N tended to decrease from the opening to maturation of new leaves and increased during the rest period. The magnitude of the decrease in the Chl and N content in the growth period of current-year leaves (&Delta;&gamma;) did not decrease noticeably as leaves aged. For the Chl content, &Delta;&gamma; was positively correlated with the maximum value before leaf opening across species. For the N content, &Delta;&gamma; and the maximum value before leaf opening were not clearly correlated across species, but were positively correlated within some species. A model parameter for annual linear trends in Chl and N varied from positive (indicating increasing trends) to negative values (indicating decrease) depending on species and leaf age in years.

Hospital-Based Surveillance and Analysis of Genotype Variation in Nicaragua After the Introduction of the Pentavalent Rotavirus Vaccine

A live, attenuated, pentavalent rotavirus vaccine (RV5) was introduced in Nicaragua in 2006 through a 3-year partnership between Merck & Co, Inc., and the Nicaraguan Ministry of Health. Nicaragua was the first developing nation to include rotavirus vaccine in its national childhood vaccine program. To monitor the possibility of changing circulating rotavirus strains after the introduction of RV5, we determined the genotypes responsible for rotavirus gastroenteritis-related hospitalization during the first 3 postvaccine years. Stool samples were collected from children with acute gastroenteritis who presented to any of 6 participating hospitals within 7-14 days of symptom onset. Samples positive for rotavirus antigen were analyzed for P and G genotypes using a reverse transcription polymerase chain reaction method. Overall, the predominant strains were G2P[4] (41.5%), G1P[8] (40.6%), G4P[8] (5.1%) and G3P[8] (4.7%). Strain predominance varied by season. During the 2007 season, G4P[8] (53.2%) and G2P[4] (40.5%) predominated. In the 2008 season, G2P[4] (77.9%) and G1P[8] (12.6%) were predominant, while in the 2009 season, G1P[8] (79.3%) and G3P[8] (7.8%) were predominant. No new or unexpected strains were predominant in the years immediately following the introduction of RV5 into Nicaragua. RV5 does not appear to have substantially altered the historical pattern of seasonal fluctuation in rotavirus genotypes.

Development and validation of a GC–MS method for the evaluation of 17 endocrine disruptor compounds, including phytoestrogens and sitosterol, in coastal waters – their spatial and seasonal levels in Porto costal region (Portugal)

A gas chromatography with mass spectrometric detection (GC-MS) method was developed and optimized for the determination of 17 endocrine disrupting compounds (EDCs) in coastal water samples. The evaluated EDCs were from different origins and included estrogens, bisphenol A, alkylphenolethoxylates, alkylphenols, phytoestrogens and sitosterol (SITO). The EDCs were extracted from samples using Oasis HLB (Hydrophilic-Lipophilic Balance) cartridges and derivatized with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) added with 1% trimethylchlorosilane (TMCS). The validation parameters revealed that this method was highly specific for all assayed compounds (>99%) and the linearity of the calibration curves showed a correlation higher than 0.99. The detection limits were at low ng/L level and the recovery rates were higher than 70%. The performance of the method was checked using coastal water samples taken every 2 months during 2009-2010 from the Douro River estuary and the Porto coastline (Portugal). These data revealed that approximately 98.0% of the analyzed compounds showed levels above their limits of detection (LODs). The measured estrogens (2-20 ng/L) and industrial pollutants (up to 1.1 μg/L) were in biologic hazardous concentrations. Besides, a clear seasonal pattern of fluctuation was established for phytoestrogens and SITO. The physicochemical data, namely the amounts of nitrates, nitrites and phosphorous, confirmed the low water quality of this area.

Determination of 17 endocrine disruptor compounds and their spatial and seasonal distribution in the Sado River Estuary (Portugal)

The Sado waters show signs of anthropogenic pollution. However, hardly any information exists on the levels of endocrine disrupters (EDCs) such as estrogens (17β-estradiol, estrone and 17α-ethynylestradiol) and there is no information at all on xenoestrogenic industrial pollutants (4-octylphenol, 4-nonylphenol and their mono and diethoxylates and bisphenol A). Moreover, data on plant derived phytoestrogens (formononetin, biochanin A, daidzein, genistein) and sitosterol are scarce or inexistent. To assess on the suspected influx of EDCs in this aquatic system, water samples were taken every two months, during 2010, at nine sites distributed along the Sado Estuary and River (Alcácer do Sal) being afterward analyzed by GC-MS. Data showed the ubiquitous presence of potentially hazardous amounts of estrogens (mainly of estrone and estradiol, reaching over 10 ng L−1), nonylphenol diethoxylate (up to 900 ng L−1) and nonylphenol (up to 230 ng L−1). It was concluded that there are conditions for the occurrence of endocrine disruption in local aquatic animals, even in areas included inside the Natural Reserve. Moreover, a clear seasonal pattern of fluctuation was found for phytoestrogens and sitosterol. Besides, there were high amounts of unionized ammonia (up to 0.6 mg L−1) and phosphates (up to 3.2 mg L−1) suggesting that the current status poses risks for local fauna and humans.