Cumulative Influence Research Articles

Land-use practices influence nutrient concentrations of southwestern Ontario streams

Human activities have transformed the landscape and altered geochemical pathways through intensive land uses such as agriculture and urbanization. This study quantified the individual and cumulative influence of land-use drivers on nutrient concentrations for 29 Ontario tributaries flowing to Lake Erie and Lake Huron. For each watershed, measures of agriculture, urbanization and population served by municipal sewage treatment plants were quantified at multiple spatial scales; stream-water nutrients (nitrogen, N, and phosphorus, P) were sampled on 10 occasions between May and November 2012, and were also compiled from government records for concurrent (2012) and prior (2007, 2008, 2011) years. Application of ordinary least squares regression analysis showed that in 2012, concentrations of N and P (total as well as dissolved forms) were primarily driven by sewage treatment and urban activity, with agricultural activity as a secondary influence on variability. Evaluation of model predictive performance under scenarios of varying climate (wet, dry and ‘normal’ conditions) and spatial coverage (i.e. broader than the original sampling sites) showed that stream nitrogen concentrations could be predicted, on average, 36–85% of the time; phosphorus forms were, however, not successfully predicted, likely due to differences in sampling frequency relative to runoff events. The finding that both urban and agricultural land-use activities influence nutrient concentrations in Canadian tributaries to lakes Erie and Huron underscores the need to reduce both point and non-point inputs in order to mitigate eutrophication of downstream lakes.

Coal Fires a major Source of Greenhouse Gases- a forgotten problem.

Coal fires seriously pollute the environment in several states of the world. Today most coal fires are manmade and emerge from illegal or unprofessional mining activities. The most disastrous coal fires of the world currently occur in China and India. In China the program "Great Leap Forward" in the beginning of the 60ties together with inefficient small scale mining are the main reasons of the 750 coal fires in China, where almost 200 Mt of excellent, near surface coal were burned in uncontrolled coal fires. In India disregard of standards with regards to coal fire prevention is the reason of the burning coal fields. The Jharia Coalfield in Jharkhand started burning in 1916 and burns this year for 100 years. General data on the volume of coal, which burns in Indian coal mines are not available. In general, coal fires start as result of unprofessional or illegal mining activities in open pits and uncontrolled, inactive coal mines by self-combustion of coal. Self-combustion is mainly controlled by the grain size of the coals, in other words the smaller the grain size the higher the risk of oxidation and subsequent temperature build-up. Many coal fires burn underground with variable supply of oxygen. Hence, the coal does not burn completely like in power plants, but it smolders in the underground. Emissions from these smoldering fires and an incomplete combustion of the coal create dust and greenhouse gases such as NOX, CO2, CO2 equi., CO and CH4. These emissions pollute the soil, groundwater and the atmosphere. Coal fire experts discuss since years the percentage and the cumulative influence of coal fires on global warming and climate change. Until now the percentage of greenhouse gases resulting from coal fires is unknown. The quantification of this percentage is a future duty of firefighting companies and organizations.

Mechanical stress increases brain amyloid β, tau, and α-synuclein concentrations in wild-type mice

IntroductionExposure to traumatic brain injury is a core risk factor that predisposes an individual to sporadic neurodegenerative diseases. We provide evidence that mechanical stress increases brain levels of hallmark proteins associated with neurodegeneration. MethodsWild-type mice were exposed to multiple regimens of repetitive mild traumatic brain injury, generating a range of combinations of impact energies, frequencies, and durations of exposure. Brain concentrations of amyloid β 1–42 (Aβ1–42), total tau, and α-synuclein were measured by sandwich enzyme-linked immunosorbent assay. ResultsThere was a highly significant main effect of impact energy, frequency, and duration of exposure on Aβ1–42, tau, and α-synuclein levels (P < .001), and a significant interaction between impact energy and duration of exposure for Aβ1–42 and tau (P < .001), but not for α-synuclein. DiscussionDose-dependent and cumulative influence of repetitive mild traumatic brain injury–induced mechanical stress may trigger and/or accelerate neurodegeneration by pushing protein concentration over the disease threshold.

Numerical simulation of plasma flows in curved coaxial ducts with longitudinal magnetic field

The results of numerical researches of plasma flows in coaxial plasma accelerators ducts of a various geometry with an external longitudinal magnetic field are presented. The non-steady-state two-dimensional MHD-model of relaxation of transonic super-Alfven flows with acceleration is considered. The paper focuses on the cumulative influence of a duct geometry and longitudinal magnetic field on flow characteristics.

African apes coexisting with logging: Comparing chimpanzee (Pan troglodytes troglodytes) and gorilla (Gorilla gorilla gorilla) resource needs and responses to forestry activities

The extraction of timber often conflicts with the well-being and conservation of wildlife. In particular, there is a need to better understand the impact of tree removal under selective logging regimes on local ecological communities. We conducted ape nest counts along line transects before, during, and after logging to assess the impact of timber harvesting and associated activities on sympatric chimpanzees and gorillas in a forestry concession in northern Republic of Congo. We used generalized linear models to relate ape nest counts to a set of predictor variables, representing the impact of logging and controlled for variation in environmental conditions including food availability, habitat and rainfall. Commercial forest inventory data were used to assess the baseline influence of food availability and forest structure on ape distribution. Higher numbers of chimpanzees were found in proximity to their preferred tree foods, whereas gorillas were associated with more heterogeneous habitats. Chimpanzee nest encounter rates decreased with increasing intensity of human impacts. Gorillas also avoided areas with active timber exploitation and roads, but were attracted to recently logged areas with abundant terrestrial herbaceous vegetation. Species-specific responses were consistent with theoretical predictions of niche partitioning and cumulative human influence. Based on these findings, we provide recommendations to improve existing guidelines and forest certification standards aimed at safeguarding ape populations.

Phytoplankton diversity of floodplain lakes of the Majuli River Island of the Brahmaputra river basin, Assam, northeast India

Phytoplankton of three floodplain lakes (beels) of the Majuli River Island of upper Assam, northeast India (NEI), sampled during September 2010–August 2012, revealed rich diversity (108 species) with Ghotonga > Holmari ≥ Bhereki beels; richness of Chlorophyta and of Cosmarium > Staurastrum > Euastrum in particular. The monthly richness and community similarities affirmed heterogeneity in phytoplankton composition. Phytoplankton comprised between 59.5±12.5, 57.1±12.3 and 48.6±13.5% of net plankton abundance of Bhereki, Holmari and Ghotonga beels, respectively. Bacillariophyta > Chlorophyta showed quantitative importance in Bhereki while Chlorophyta > Bacillariophyta recorded importance in Holmari and Ghotonga beels. Cyanophyta showed sub-dominance and Dinophyta > Euglenophyta showed low densities in the three beels. Phytoplankton richness and abundance followed oscillating monthly variations; ANOVA registered insignificant richness variations amongst beels. The results are characterized certain monthly and annual variations but mean values depicted high species diversity, low dominance and high equitability. Individual and cumulative influence ( vide CCA) yielded limited insight on the role of seventeen abiotic factors on phytoplankton in Holmari and Bhereki beels.

Cumulative influence: the case of political settlements research in British policy

ABSTRACTThe concept of the political settlement has risen to occupy a central place in British policy toward conflict-affected and fragile states. Yet, at around the turn of the millennium, the term was barely mentioned in official circles and the so-called ‘good governance’ approach held sway as the dominant operational mode. So, how had this transformation in policy approach come about and what was the role of research? In this article, we demonstrate that research played a central role in influencing the rhetoric of policymakers through a process we term ‘cumulative influence’. Indeed, the subject of political settlements represents an excellent case study for understanding the dynamics of research utilisation. It allows us to build on existing models and suggest useful ways forward in this important area of public policy analysis.

Human development and climate affect hibernation in a large carnivore with implications for human–carnivore conflicts

Abstract Expanding human development and climate change are dramatically altering habitat conditions for wildlife. While the initial response of wildlife to changing environmental conditions is typically a shift in behaviour, little is known about the effects of these stressors on hibernation behaviour, an important life‐history trait that can subsequently affect animal physiology, demography, interspecific interactions and human‐wildlife interactions. Given future trajectories of land use and climate change, it is important that wildlife professionals understand how animals that hibernate are adapting to altered landscape conditions so that management activities can be appropriately tailored. We investigated the influence of human development and weather on hibernation in black bears (Ursus americanus), a species of high management concern, whose behaviour is strongly tied to natural food availability, anthropogenic foods around development and variation in annual weather conditions. Using GPS collar data from 131 den events of adult female bears (n = 51), we employed fine‐scale, animal‐specific habitat information to evaluate the relative and cumulative influence of natural food availability, anthropogenic food and weather on the start, duration and end of hibernation. We found that weather and food availability (both natural and human) additively shaped black bear hibernation behaviour. Of the habitat variables we examined, warmer temperatures were most strongly associated with denning chronology, reducing the duration of hibernation and expediting emergence in the spring. Bears appeared to respond to natural and anthropogenic foods similarly, as more natural foods, and greater use of human foods around development, both postponed hibernation in the fall and decreased its duration. Synthesis and applications. Warmer temperatures and use of anthropogenic food subsides additively reduced black bear hibernation, suggesting that future changes in climate and land use may further alter bear behaviour and increase the length of their active season. We speculate that longer active periods for bears will result in subsequent increases in human–bear conflicts and human‐caused bear mortalities. These metrics are commonly used by wildlife agencies to index trends in bear populations, but have the potential to be misleading when bear behaviour dynamically adapts to changing environmental conditions, and should be substituted with reliable demographic methods.

JUSTIFYING WATER SENSITIVE DEVELOPMENT: SCIENCE INFORMING POLICY AND PRACTICE

This New Zealand research focuses on providing evidence that a specified residential land use layout plus „at source‟ stormwater management results in higher aquatic ecosystem health. The evidence provides justification for changes in statutory plans, policies and practice rules that direct urban development. The surveyed sites are within river basins clustered by similar residential land use density. Each cluster includes one river basin with conventional urban form and drainage. Other comparative basins in the cluster typify a „water sensitive‟ urban form and infrastructure. An index of biotic integrity (indicating river health) is determined for each waterway at annual intervals over years. Current plan requirements, policies and practice guidelines for urban development are critiqued in relation to survey results. The cumulative influence of defined residential river basin characteristics (drivers) are related to the holistic biotic indices. Combined drivers determine the cumulative aquatic health outcome. Research methods typically don‟t target the effects of a single driver. Policy, plan and practice requirements need to guide urban design and construction to incorporate the elements of urban form that are together necessary for aquatic health. This will ensure an order of magnitude improvement in the functionality and recreational appeal of streams, wetlands, lakes and recipient harbours. Keywords: Water sensitive urban design; biotic integrity; urban planning

Impact of Water-Induced Processes on the Development of Tarns and Their Basins in the High Tatras

Abstract In the report we concentrate on the influences of water-induced morphodynamic processes and surface flow on the development of tarns in alpine environment conditions of selected valleys in the High Tatras. Model areas are represented by higher basins parts in the Malá Studená valley and the Veľká Studená valley, where we confirmed that slope-gravitational processes in the form of rockfall, water-gravitational processes in the form of debris flows, but also fluvial-proluvial processes as the accumulation of the soft fractions from the area of debris cones take part in the material deposition in the tarns. In this context we focused on the creation of the model of spatial distribution of the water-induced potential of material deposition in drainage tarn basins. The model includes three basic factors: slope and curvature of the relief and land cover character. Map processing with GIS technologies was done on the basis of a 3-D relief model, which allowed the locating of the local erosion bases areas, where the material could be accumulated. The achieved results confirmed the hypothesis that tarn basin development of the alpine environment is subordinated to permanent backfilling as a consequence of the cumulative influence of the several processes connected with rainfall and the runoff regime of the drainage basins.

Influence of topography on glacier changes in the central Himalaya, India

Assessing the impact of topography on glacier changes is vital because, while climate is the driving force behind these changes, the topography may control their heterogeneity. Present study provides a detailed insight into varied responses of 18 glaciers (1994–2015), spread over the central Himalaya (CH), and systematically explores the influence of topographic factors on changing glacier parameters using satellite remote sensing data (Landsat TM/ETM+/OLI, Cartosat-1 PAN, Resoursesat-2 LISS-4, SRTM digital elevation model) and limited field observations. Results show that the total glaciated area decreased from 313.34±7.95km2 in 1994 to 306.36±8.04km2 in 2015 whereas retreat rates varied from 4.75±2.25 to 28.25±2.25ma−1 during this period. The total debris-covered area also increased from 86.56±1.29 to 97.99±1.75km2 and the average snowline altitude upshifted by 67m during 1994–2015. Various topographic factors analyzed here include: glacier area, length, compactness ratio, altitude, slope, aspect, hypsometry, area accumulation ratio and snout characteristics. Multivariate statistical analysis demonstrates that compactness ratio, glacier size, altitude range and mean slope strongly influence the area loss. Whereas glacier length, mean slope, compactness and altitude range influence the retreat rates. Cumulative influence of these factors was assessed using a novel approach which uses ordinal scale relative weighting-rating technique to compute a Topographic Influence Index (TII). Breaks in the frequency of TII values were used for categorizing the glaciers into three groups that experienced different degrees of topographic influence on area loss and retreat namely, modest, moderate and strong. It is observed that, out of 18 glaciers, 5 had modest, 8 had moderate and 5 glaciers had strong influence of topography on area loss. Whereas, 6, 8 and 4 glaciers experienced modest, moderate and strong influence of topography on retreat, respectively. Further, we found that ~78% and ~61% glaciers in case of area loss and retreat, respectively, are also the ones which exhibit higher glacier wastage. This indicates that the observed heterogeneity in the response of studied glaciers is probably topographically induced.

Rotifers (Rotifera: Eurotatoria) from floodplain lakes of the Dibru Saikhowa Biosphere Reserve, upper Assam, northeast India: ecosystem diversity and biogeography

This study aims to assess ecosystem diversity of Rotifera of the floodplain lakes (beels) of the Brahmaputra river basin with reference to faunal diversity of the taxon in wetlands of conservation areas of India. We observed 141 rotifer species, belonging to 31 genera and 17 families, from three beels of the Dibru-Saikhowa Biosphere Reserve (DSBR) of Assam, northeast India (NEI) with high total richness (117±2 species) in individual beels. One, two and three species are new to the Oriental region, India and Assam state, respectively and 21 species are globally interesting. The diverse Lecanidae > Lepadellidae > Trichocercidae; the paucity and scarceness of Brachionidae and Brachionus spp. in particular; and rare nature of Keratella , Filinia , Asplanchna , Polyarthra , and Conochilus are salient. The monthly richness and community similarities affirmed heterogeneity in species composition in individual beels while this study exhibited overall rotifer homogeneity amongst beels. The richness followed monthly oscillations in the three beels and lacked significant variations amongst beels. The peak richness of 76 species during summer (May, 2014) from No. 11 beel is one of the richest rotifer assemblages known in single date collection from an aquatic ecosystem of South Asia. Our results explained little influence of individual abiotic factors while canonical correspondence analysis endorsed high cumulative influence of 17 abiotic factors on richness in all beels.

The women made it work: fuzzy transitive closure of the results chain in a dengue prevention trial in Mexico

BackgroundA modified theory of planned behaviour (acronym CASCADA) proposes that Conscious knowledge precedes a change in Attitude, which in turn precedes positive deviations from negative Subjective norms, intention to Change, perception of Agency to change, Discussion of possible action, and Action itself. We used this as a results chain to investigate gender-specific behaviour dynamics in chemical-free dengue prevention.MethodsSecondary analysis of the Mexican arm of a cluster randomised controlled trial used household survey data on intermediate outcomes of dengue prevention behaviour. We used a matrix of odds ratios between outcomes, transformed to a symmetrical range (−1, 1), to compute fuzzy transitive closure of the results chain for control and intervention clusters, then for male and female respondents separately in each group. Transitive closure of a map computes the influence of each factor on each other factor, taking account of all influences in the system. Cumulative net influence was the sum of influences across the results chain.ResultsResponses of 5042 women and 1143 men in 45 intervention clusters contrasted with those of 5025 women and 1179 men in 45 control clusters. Control clusters showed a distal block (negative influence) in the results chain with a cumulative net influence of 0.88; intervention clusters showed no such block and a cumulative net influence of 1.92. Female control respondents, like the overall control picture, showed a distal block, whereas female intervention responses showed no such blocks (cumulative net influence 0.78 and 1.73 respectively). Male control respondents showed weak distal blocks. Male intervention responses showed several new negative influences and a reduction of cumulative net influence (1.38 in control and 1.11 in intervention clusters).ConclusionsThe overall influence of the intervention across the results chain fits with the trial findings, but is different for women and men. Among women, the intervention overcame blocks and increased the cumulative net influence of knowledge on action. Among men, the intervention did not reinforce prevention behaviour. This might be related to emphasis, during the intervention, on women’s participation and empowerment. The fuzzy transitive closure of the CASCADA map usefully highlights the differences between gender-specific results chains.Trial registrationISRCTN27581154.

Abstract IA11: Life course epidemiology and breast cancer: translating risk into prevention

Abstract Molecular histology may be conceptualized as the microscopic and molecular characteristics of normal tissues that are required for physiologic function. Over the life course, the molecular histology of the breast changes in response to physiological alterations, imparting spatial and temporal heterogeneity within the breasts of individuals and among women. These transitions contribute to the enormous range and imprecisely defined limits of what pathologists consider normal. Appreciation that molecular histology may reflect the cumulative influence of prior exposures linked to breast cancer risk, and may provide information about risk of developing breast cancer in the future, has stimulated interest in this topic. Unlike the study of breast cancer or its precursors, which represents a focal pathophysiologic deviation from normal, molecular histology, if assessable, would represent the state of the entire at-risk organ, based upon examination of a small tissue sample. The adult breast is characterized by well-developed terminal duct lobular units (TDLUs), which comprise the functional unit of milk production and represent the source of nearly all breast cancer precursors. Physiological changes in human breasts are likely driven by paracrine mechanisms, suggesting that tissue context and cellular topography are critical elements in physiology and pathophysiology. The breast undergoes profound changes with completion of childbearing and aging. Age-related TDLU involution may be conceptualized as a protective mechanism that lowers breast cancer risk following completion of childbearing, and in this context, delayed or incomplete involution is a breast cancer risk factor. With aging, the percent of the breast comprised of fibroglandular tissue declines, which is associated with a reduction in mammographic density, a strong breast cancer risk factor. Mammographic density is also imperfectly correlated with epithelial content in the breast. Women with benign breast disease whose surrounding normal breast tissue does not undergo age-appropriate TDLU involution are at increased risk of developing breast cancer, and both breast density and TDLU involution are independent markers of breast cancer risk. However, an important challenge is to understand the markers and mechanisms that underlie breast involution with aging, including both the epithelial and non-epithelial components, and to learn why both density and TDLU content decline with aging as breast cancer incidence rises. The thesis of this presentation is that understanding the amount of epithelium at-risk, the insults it sustains and the mechanisms that lead to its elimination, persistence or expansion may provide a window into the development of integrative biomarkers of risk that can translate into improved screening and prevention. However, progress towards this goal is quite early. Citation Format: Mark E. Sherman. Life course epidemiology and breast cancer: translating risk into prevention. [abstract]. In: Proceedings of the AACR Special Conference: Improving Cancer Risk Prediction for Prevention and Early Detection; Nov 16-19, 2016; Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2017;26(5 Suppl):Abstract nr IA11.

Biodiverse rotifer assemblage (Rotifera: Eurotatoria) of floodplain lakes of the Brahmaputra basin of lower Assam, northeast India: composition and ecosystem diversity

The study aims to ascertain the hypothesis on the rich rotifer biodiversity of the floodplain lakes (beels) of the Brahmaputra river basin and to use these metazoans to assess trophic status or to characterize habitat variations of wetlands. The plankton samples collected from four beels of lower Assam revealed 160 Rotifera species belonging to 35 genera and 19 families. The richness is of biodiversity value as ~38.0% and ~57.0% of the rotifer species known till date from India and northeast India (NEI), respectively. One species each is new to the Oriental region and NEI, and three species are new to Assam; 23 species merit global biogeography interest and several exhibit distribution values in the Indian sub-region. The diverse Lecanidae > Brachionidae > Lepadellidae > Trichocercidae and speciose littoral-periphytic Lecane > Lepadella > Trichocerca, and richness of Brachionus spp. following removal of aquatic macrophytes are noteworthy. Overall rotifer composition showed homogeneity amongst beels while lower monthly richness and community similarities affirmed heterogeneity within individual beels. We propose L/B quotient based on Lecane: Brachionus species ratios to characterize habitat variations of the sampled wetlands. Sladecek’s B/T quotient based on Brachionus: Trichocerca species ratios affirmed general’ meso-trophic’ status of different beels. Our results provided little insight on the influence of individual abiotic factors but the canonical correspondence analyses asserted higher cumulative influence of ten abiotic parameters on Rotifera richness in each beel.

Poorer prognosis associated with simultaneous lymphatic and vascular invasion in patients with squamous carcinoma of the thoracic oesophagus.

The objective of this study was to demonstrate the cumulative influence of simultaneous lymphatic and vascular invasion in thoracic oesophageal squamous carcinoma after radical operation. A total of 598 cases with thoracic oesophageal squamous carcinoma that were cured by radical open oesophagectomy and extensive lymphadenectomy in the period of 2002 to 2014 were included. An association of the status of lymphovascular invasion with clinicopathological factors and a recurrent pattern was illustrated. Overall survival and disease-free survival were calculated, and the risk factors for decreased disease-free survival were determined with Kaplan-Meier subset analyses and Cox regression analysis. The status of lymphovascular invasion was significantly associated with tumour differentiation ( P = 0.045) and the pathological tumour, node and metastasis stage ( P < 0.001), which includes the tumour intramural invasive depth (T parameter) as well as regional (N parameter) and distant (M parameter) lymph node involvement. The 1-, 3- and 5-year overall survival and postoperative disease-free survival were significantly decreased by lymphatic or vascular invasion alone ( P < 0.001) and were further decreased by simultaneous lymphatic and vascular invasion ( P < 0.001). The independent risk factors that predicted reduced disease-free survival were the following: T parameter ( P < 0.001, odds ratio: 1.436), N parameter ( P < 0.001, odds ratio: 1.838) and the status of lymphovascular invasion ( P < 0.001, odds ratio: 1.568). Simultaneous lymphatic and vascular invasion were significantly correlated with postoperative early recurrence ( P = 0.037). Simultaneous lymphatic and vascular invasion independently has a more adverse effect on prognosis than lymphatic or vascular invasion alone. Differentiating between lymphatic and vascular invasion is recommended in order to further study the role of lymphovascular invasion in cancer staging and prognostication in multicentre prospective studies.

Sperm in hot water: direct and indirect thermal challenges interact to impact on brown trout sperm quality.

Climate change alters the thermal habitat of aquatic species on a global scale, generating novel environmental challenges during all life stages, including reproduction. Changes in water temperature profoundly influence the performance of ectothermic aquatic organisms. This is an especially crucial issue for migratory fish, because they traverse multiple environments in order to reproduce. In externally fertilizing migratory fish, gametes are affected by water temperature indirectly, within the reproductive organ in which they are produced during migration, as well as directly, upon release into the surrounding medium at the spawning grounds. Both direct (after release) and indirect (during production) thermal impacts on gamete quality have been investigated, but never in conjunction. Here, we assessed the cumulative influence of temperature on brown trout, Salmo trutta, sperm quality during sperm production (male acclimation temperature) as well as upon release (sperm activation water temperature) on two consecutive dates during the brown trout spawning season. Early in the season, warm acclimation of males reduced their fertilization probability (lower sperm velocity) when compared with cold-acclimated males, especially when the activation water temperature was also increased beyond the thermal optimum (resulting in a lower proportion of motile sperm with lower velocity). Later in the season, sperm quality was unaffected by acclimation temperature and thermal sensitivity of sperm was reduced. These results give novel insights into the complex impacts of climate change on fish sperm, with implications for the reproduction and management of hatchery and wild trout populations in future climate scenarios.

Diversity of Phytoplankton of a sub-tropical reservoir of Mizoram, northeast India

Phytoplankton of Khawiva reservoir of Mizoram, northeast India (NEI) revealed a total of 55 species; nearly concurrent mean monthly richness and high community similarities ( vide Sorensen index) during two years affirmed homogeneity in its species composition. Phytoplankton comprised dominant component (61.1±14.3%) of net plankton and recorded wider density variations. Chlorophyta influenced phytoplankton abundance with quantitative importance of Staurastrum spp. > Xanthidium spp. > Cosmarium spp. in particular. Bacillariophyta formed subdominant group; Cryptophyta and Cyanophyta showed limited importance; and Euglenophyta and Dinophyta recorded poor densities. Phytoplankton is characterized by moderate species diversity, high evenness and low dominance but with wide variations. Richness, abundance and species diversity followed no definite patterns of monthly variations during two years. Insignificant influence of individual abiotic factors on phytoplankton assemblages coupled with low cumulative influence of fifteen abiotic parameters ( vide CCA) yielded little insight on overall role of abiotic parameters.

The long-term health impacts of Medicaid and CHIP

This paper estimates the effect of US public health insurance programs for children on health. Previous work in this area has typically focused on the relationship between current program eligibility and current health. But because health is a stock variable which reflects the cumulative influence of health inputs, it would be preferable to estimate the impact of total program eligibility during childhood on longer-term health outcomes. I provide such estimates by using longitudinal data to construct Medicaid and CHIP eligibility measures that are observed from birth through age 18 and estimating the effect of cumulative program exposure on a variety of health outcomes observed in early adulthood. To account for the endogeneity of program eligibility, I exploit variation in Medicaid and CHIP generosity across states and over time for children of different ages. I find that an additional year of public health insurance eligibility during childhood improves a summary index of adult health by.079 standard deviations, and substantially reduces health limitations, chronic conditions and asthma prevalence while improving self-rated health.

Compositional changes in thermophilous oak forests in Poland over time: do they correspond to European trends?

AbstractQuestionsHave compositional changes occurred in thermophilous oak forests in Poland during the past two decades? What kinds of drivers might be responsible for these changes? Are the thermophilous oak woods still rich in species or have they rather lost their diversity?LocationSudetes Mts., SW Poland.MethodsThe vegetation of thermophilous oak forests within four distinct areas was surveyed on 92 semi‐permanent plots in the time periods from 1992 to 1994 and from 2010 to 2014. The overall pattern in vegetation changes, trends in species composition and site parameters, as well as the diversity of studied communities were analysed using ordination and permutation techniques.ResultsThe species composition of thermophilous oak forests has changed significantly. We recorded a decrease in the share of oligotrophic light‐demanding species, whereas mesotrophic light‐demanding and nitrophilous species showed an upward trend. Regarding the fourth group of shade‐tolerant species, their share varied depending on the site. The analysis of habitat parameters revealed that the studied oak forest communities generally shifted from communities of moderately oligotrophic and mesic character towards forests growing on nutrient‐richer but drier habitats. Interestingly, the observed change in species composition was not accompanied by the loss of biodiversity that has generally been reported in other types of thermophilous forests in Europe.ConclusionsChanges observed within thermophilous and previously coppiced oak forests of southwest Poland are going in a direction which has not been recognized so far in analogous communities. The transition of studied communities is probably a result of the cumulative influence of several drivers, the most crucial of which seem to be soil regeneration, after the period of intensive acidity caused by sulphur emission between 1960 and 2000, and decreasing moisture. The observed changes are independent of the type of forest management (or the lack thereof) within the study sites.