Drought resistance in early and late secondary successional species from a tropical dry forest: the interplay between xylem resistance to embolism, sapwood water storage and leaf shedding.

PubMed

Pineda-García, Fernando; Paz, Horacio; Meinzer, Frederick C

2013-02-01

The mechanisms of drought resistance that allow plants to successfully establish at different stages of secondary succession in tropical dry forests are not well understood. We characterized mechanisms of drought resistance in early and late-successional species and tested whether risk of drought differs across sites at different successional stages, and whether early and late-successional species differ in resistance to experimentally imposed soil drought. The microenvironment in early successional sites was warmer and drier than in mature forest. Nevertheless, successional groups did not differ in resistance to soil drought. Late-successional species resisted drought through two independent mechanisms: high resistance of xylem to embolism, or reliance on high stem water storage capacity. High sapwood water reserves delayed the effects of soil drying by transiently decoupling plant and soil water status. Resistance to soil drought resulted from the interplay between variations in xylem vulnerability to embolism, reliance on sapwood water reserves and leaf area reduction, leading to a tradeoff of avoidance against tolerance of soil drought, along which successional groups were not differentiated. Overall, our data suggest that ranking species' performance under soil drought based solely on xylem resistance to embolism may be misleading, especially for species with high sapwood water storage capacity. © 2012 Blackwell Publishing Ltd.

Patterns and trends of early successional forests in the Eastern United States

Treesearch

Margaret K. Trani; Robert T. Brooks; Thomas L. Schmidt; Victor A. Rudis; Christine M. Gabbard

2001-01-01

We assessed the status of early successional forest conditions for 33 Eastern States within the New England, Middle Atlantic, Great Lakes, Central Plains, Coastal South, and Interior South subregions. We used Forest Inventory and Analysis surveys to analyze trends from 1946 to 1998. Dramatic regional differences occurred in distribution of early successional forests....

Encouraging family forest owners to create early successional wildlife habitat in Southern New England.

PubMed

Buffum, Bill; Modisette, Christopher; McWilliams, Scott R

2014-01-01

Encouraging family forest owners to create early successional habitat is a high priority for wildlife conservation agencies in the northeastern USA, where most forest land is privately owned. Many studies have linked regional declines in wildlife populations to the loss of early successional habitat. The government provides financial incentives to create early successional habitat, but the number of family forest owners who actively manage their forests remains low. Several studies have analyzed participation of family forest owners in federal forestry programs, but no study to date has focused specifically on creation of wildlife habitat. The objective of our study was to analyze the experience of a group of wildlife-oriented family forest owners who were trained to create early successional habitat. This type of family forest owners represents a small portion of the total population of family forest owners, but we believe they can play an important role in creating wildlife habitat, so it is important to understand how outreach programs can best reach them. The respondents shared some characteristics but differed in terms of forest holdings, forestry experience and interest in earning forestry income. Despite their strong interest in wildlife, awareness about the importance of early successional habitat was low. Financial support from the federal government appeared to be important in motivating respondents to follow up after the training with activities on their own properties: 84% of respondents who had implemented activities received federal financial support and 47% would not have implemented the activities without financial assistance. In order to mobilize greater numbers of wildlife-oriented family forest owners to create early successional habitat we recommend focusing outreach efforts on increasing awareness about the importance of early successional habitat and the availability of technical and financial assistance.

Encouraging Family Forest Owners to Create Early Successional Wildlife Habitat in Southern New England

PubMed Central

Buffum, Bill; Modisette, Christopher; McWilliams, Scott R.

2014-01-01

Encouraging family forest owners to create early successional habitat is a high priority for wildlife conservation agencies in the northeastern USA, where most forest land is privately owned. Many studies have linked regional declines in wildlife populations to the loss of early successional habitat. The government provides financial incentives to create early successional habitat, but the number of family forest owners who actively manage their forests remains low. Several studies have analyzed participation of family forest owners in federal forestry programs, but no study to date has focused specifically on creation of wildlife habitat. The objective of our study was to analyze the experience of a group of wildlife-oriented family forest owners who were trained to create early successional habitat. This type of family forest owners represents a small portion of the total population of family forest owners, but we believe they can play an important role in creating wildlife habitat, so it is important to understand how outreach programs can best reach them. The respondents shared some characteristics but differed in terms of forest holdings, forestry experience and interest in earning forestry income. Despite their strong interest in wildlife, awareness about the importance of early successional habitat was low. Financial support from the federal government appeared to be important in motivating respondents to follow up after the training with activities on their own properties: 84% of respondents who had implemented activities received federal financial support and 47% would not have implemented the activities without financial assistance. In order to mobilize greater numbers of wildlife-oriented family forest owners to create early successional habitat we recommend focusing outreach efforts on increasing awareness about the importance of early successional habitat and the availability of technical and financial assistance. PMID:24587160

Canopy Nutrient Cycling In Afromontane Tropical Forests At Different Successional Stages

NASA Astrophysics Data System (ADS)

Nyirambangutse, B.; Zibera, E.; Dusenge, M. E.; Nsabimana, D.; Pleijel, H.; Uddling, J.; Wallin, G.

2017-12-01

Canopy nutrient composition and cycling control biogeochemical processes and tree growth in forests. However, the understanding of nutrient limitations and cycling in tropical montane forests (TMF) is currently limited, in particular for Afromontane forests. In this study we investigated leaf nutrient composition and resorption, canopy nutrient cycling and soil carbon and nutrient content in 15 permanent plots at different successional stages in a TMF (elevation 1950 to 2550 m a.s.l.) in Rwanda, Central Africa. Leaf concentrations of 12 elements were analyzed in attached green leaves as well as in shed leaves of 10 early (ES) and 10 late (LS) successional tree species. Leaf nutrient concentrations mostly did not differ between ES and LS species (exception: K was 20% higher in ES), but the ratios of P, K and Mg to N were significantly higher in ES species. Mean resorption efficiencies of N (37%), P (48%) and K (46%) were much higher than for other nutrients. Nutrient resorption efficiency exhibited very large interspecific variation, did not differ between ES and LS species, and was not related to the leaf concentration of the respective element. Total leaf litterfall was on average 4.9 t ha-1 yr-1 (66% of total litterfall) and was independent of the successional stage of the forest. The total content of C, N, P and K in leaf litterfall did not differ between ES and LS stands. Ground litter turnover rates of C and N were 0.98 and 0.78 y-1, respectively. High leaf N concentrations, intermediate N:P ratios and low resorption efficiencies compared to values reported for other TMFs indicate high fertility and likely co-limitation by N and P, however progressively increasing towards P limitation during the course of succession. Our results further demonstrate that resorption efficiency and canopy litterfall inputs to soil mostly do not differ between ES and LS species in Afromontane tropical forests.

Early successional forest habitats and water resources

Treesearch

James Vose; Chelcy Ford

2011-01-01

Tree harvests that create early successional habitats have direct and indirect impacts on water resources in forests of the Central Hardwood Region. Streamflow increases substantially immediately after timber harvest, but increases decline as leaf area recovers and biomass aggrades. Post-harvest increases in stormflow of 10–20%, generally do not contribute to...

Influence of biological soil crusts at different successional stages in the implantation of biogeochemical cycles in arid and semiarid zones

NASA Astrophysics Data System (ADS)

Gil-Sotres, F.; Miralles, I.; Canton-Castilla, Y.; Domingo, F.; Leiros, M. C.; Trasar-Cepeda, C.

2012-04-01

Influence of biological soil crusts at different successional stages in the implantation of biogeochemical cycles in arid and semiarid zones I. Miralles1, F. Gil-Sotres2, Y. Cantón-Castilla3, F. Domingo1, M.C. Leirós2, C. Trasar-Cepeda4 1 Experimental Estation of Arid Zones (CSIC), E-04230 La Cañada de San Urbano, Almería, Spain. 2 Departamento Edafología y Química Agrícola, Grupo de Evaluación de la Calidad del Suelo, Unidad Asociada CSIC, Facultad de Farmacia, Universidad de Santiago de Compostela, E-15782 Santiago de Compostela, Spain. 3 University of Almería, Departamento de Edafología y Química Agrícola, E-04230-La Cañada de San Urbano, Almería, Spain. 4 Departamento Bioquímica del Suelo, IIAG-CSIC, Apartado 122, E-15708 Santiago de Compostela, Spain. Crusts (BSCs) are formed by a close association between soil particles and cyanobacteria, algae, lichens, bryophytes and microfungi in varying proportions. Their habitat is within or immediately on top of the uppermost millimetres of the soil and are the predominant surface cover in arid and semiarid zones. Among the diverse functions developed by BSCs in the ecosystem (hydrology, erosion, soil properties, etc.), one of the most important is its role in nutrient cycling. Within arid and semiarid environments, BSCs have been termed 'mantles of fertility' being considered hotspots of biogeochemical inputs, fixing C, N and P above- and below-ground. However, there are differences in N and C fixation rates between BSCs types. Early successional BSCs, dominated by cyanobacterial species, fix lower quantities of C and N than mature BSCs dominated by lichens. Although the positive effects of BSCs on biogeochemical soil cycles are widely accepted, no previous studies have evaluated the activities of the enzymes involved in C, N and P cycles of BSCs and how they are affected by the successional stage of the BSC. In this work, performed in the Tabernas desert (SE Spain), we studied the hydrolase enzymes

Abundance, distribution, trends, and ownership patterns of early successional forests in the northeastern United States

Treesearch

Robert T. Brooks

2003-01-01

Early-successional forests are ephemeral and distinct forest communities, maintained by disturbance and dominated by small-sized trees and shrubs. These structural and compositional conditions form a unique habitat that is preferred by many wildlife species. Various sources have indicated that there have been declines in early-successional forest area and in the...

Changes in early-successional hardwood forest area in four bird conservation regions across four decades

Treesearch

Sonja N. Oswalt; Kathleen E. Franzreb; David A. Buehler

2012-01-01

Early successional hardwood forests constitute important breeding habitat for many migratory songbirds. Declines in populations of these species suggest changes in habitat availability either on the species’ wintering grounds or on their early successional breeding grounds. We used Forest Inventory and Analysis data from 11 states across four decades to examine changes...

Variation in the effects of burial in different peatland successional stages on seed survival of four wetland species

NASA Astrophysics Data System (ADS)

Egawa, Chika

2017-01-01

The availability of viable seeds in soil helps to determine the success of ecological restoration in disturbed habitats. Although seed survival in soil generally increases with an increase in burial depth, whether the effects of burial on seed survival are comparable across different sites is unclear. In this study, I tested the hypothesis that the positive effects of burial on seed survival decrease as vegetation develops through succession. Four wetland species, Drosera rotundifolia, Lobelia sessilifolia, Rhynchospora alba and Moliniopsis japonica, were used for the study. The four species differ in their light requirement for germination; i.e., D. rotundifolia, L. sessilifolia and R. alba germinate best in light, whereas M. japonica germinates equally well in light and darkness. The seeds of these species were buried for two years at three depths (litter, 0 and 4 cm) in three successional stages with different amounts of vegetation and litter in a post-mined peatland. The photosynthetically active radiation (PAR) and temperature at each of litter layer, 0 cm and 4 cm depths were measured for each successional stage. The between-depth differences in PAR and temperature fluctuations decreased as succession progressed. For the three light-demanding species, burial promoted seed survival more in the initial successional stage than in the later successional stages, whereas for M. japonica, burial promoted seed survival equally in all successional stages. This study revealed significant variation in the effects of burial on seed survival, particularly for light-sensitive seeds, and that the soil surface layers in vegetated sites can contain persistent seeds, which could be used as a seed source in restoration.

Changing contributions of stochastic and deterministic processes in community assembly over a successional gradient.

PubMed

Måren, Inger Elisabeth; Kapfer, Jutta; Aarrestad, Per Arild; Grytnes, John-Arvid; Vandvik, Vigdis

2018-01-01

Successional dynamics in plant community assembly may result from both deterministic and stochastic ecological processes. The relative importance of different ecological processes is expected to vary over the successional sequence, between different plant functional groups, and with the disturbance levels and land-use management regimes of the successional systems. We evaluate the relative importance of stochastic and deterministic processes in bryophyte and vascular plant community assembly after fire in grazed and ungrazed anthropogenic coastal heathlands in Northern Europe. A replicated series of post-fire successions (n = 12) were initiated under grazed and ungrazed conditions, and vegetation data were recorded in permanent plots over 13 years. We used redundancy analysis (RDA) to test for deterministic successional patterns in species composition repeated across the replicate successional series and analyses of co-occurrence to evaluate to what extent species respond synchronously along the successional gradient. Change in species co-occurrences over succession indicates stochastic successional dynamics at the species level (i.e., species equivalence), whereas constancy in co-occurrence indicates deterministic dynamics (successional niche differentiation). The RDA shows high and deterministic vascular plant community compositional change, especially early in succession. Co-occurrence analyses indicate stochastic species-level dynamics the first two years, which then give way to more deterministic replacements. Grazed and ungrazed successions are similar, but the early stage stochasticity is higher in ungrazed areas. Bryophyte communities in ungrazed successions resemble vascular plant communities. In contrast, bryophytes in grazed successions showed consistently high stochasticity and low determinism in both community composition and species co-occurrence. In conclusion, stochastic and individualistic species responses early in succession give way to more

Douglas-fir ectomycorrhizae in 40- and 400-year-old stands: mycobiont availability to late successional western hemlock.

Treesearch

T. R. Horton; R. Molina; K. Hood

2005-01-01

We investigated ectomycorrhizal (EM) fungi in forest stands containing both early successional Douglas-fir and late successional western hemlock at two points in the typical stand development by identifying EM fungi from roots of Douglas-fir and western hemlock in mixed stands. Tn an early seral stage forest, EM roots of western hemlock seedlings and intermingling 40-...

Facilitative and inhibitory effect of litter on seedling emergence and early growth of six herbaceous species in an early successional old field ecosystem.

PubMed

Li, Qiang; Yu, Pujia; Chen, Xiaoying; Li, Guangdi; Zhou, Daowei; Zheng, Wei

2014-01-01

In the current study, a field experiment was conducted to examine effects of litter on seedling emergence and early growth of four dominant weed species from the early successional stages of old field ecosystem and two perennial grassland species in late successional stages. Our results showed that increased litter cover decreased soil temperature and temperature variability over time and improved soil moisture status. Surface soil electrical conductivity increased as litter increased. The increased litter delayed seedling emergence time and rate. The emergence percentage of seedlings and establishment success rate firstly increased then decreased as litter cover increased. When litter biomass was below 600 g m(-2), litter increased seedlings emergence and establishment success in all species. With litter increasing, the basal diameter of seedling decreased, but seedling height increased. Increasing amounts of litter tended to increase seedling dry weight and stem leaf ratio. Different species responded differently to the increase of litter. Puccinellia tenuiflora and Chloris virgata will acquire more emergence benefits under high litter amount. It is predicted that Chloris virgata will dominate further in this natural succession old field ecosystem with litter accumulation. Artificial P. tenuiflora seeds addition may be required to accelerate old field succession toward matured grassland.

Facilitative and Inhibitory Effect of Litter on Seedling Emergence and Early Growth of Six Herbaceous Species in an Early Successional Old Field Ecosystem

PubMed Central

Li, Qiang; Yu, Pujia; Chen, Xiaoying; Li, Guangdi; Zhou, Daowei; Zheng, Wei

2014-01-01

In the current study, a field experiment was conducted to examine effects of litter on seedling emergence and early growth of four dominant weed species from the early successional stages of old field ecosystem and two perennial grassland species in late successional stages. Our results showed that increased litter cover decreased soil temperature and temperature variability over time and improved soil moisture status. Surface soil electrical conductivity increased as litter increased. The increased litter delayed seedling emergence time and rate. The emergence percentage of seedlings and establishment success rate firstly increased then decreased as litter cover increased. When litter biomass was below 600 g m−2, litter increased seedlings emergence and establishment success in all species. With litter increasing, the basal diameter of seedling decreased, but seedling height increased. Increasing amounts of litter tended to increase seedling dry weight and stem leaf ratio. Different species responded differently to the increase of litter. Puccinellia tenuiflora and Chloris virgata will acquire more emergence benefits under high litter amount. It is predicted that Chloris virgata will dominate further in this natural succession old field ecosystem with litter accumulation. Artificial P. tenuiflora seeds addition may be required to accelerate old field succession toward matured grassland. PMID:25110722

Biological significance of dead biomass retention trait in Mediterranean Basin species: an analysis between different successional niches and regeneration strategies as functional groups.

PubMed

Baeza, M J; Santana, V M

2015-11-01

Standing dead biomass retention is considered one of the most relevant fuel structural traits to affect plant flammability. However, very little is known about the biological significance of this trait and its distribution between different functional groups. Our aim was to analyse how the proportion of dead biomass produced in Mediterranean species is related to the successional niche of species (early-, mid- and late-successional stages) and the regeneration strategy of species (seeders and resprouters). We evaluated biomass distribution by size classes and standing dead biomass retention in nine dominant species from the Mediterranean Basin in different development stages (5, 9, 14 and 26 years since the last fire). The results revealed significant differences in the standing dead biomass retention of species that presented a distinct successional niche or regeneration strategy. These differences were restricted to the oldest ages studied (>9 years). Tree and small tree resprouters, typical in late-successional stages, presented slight variations with age and a less marked trend to retain dead biomass, while seeder shrubs and dwarf shrubs, characteristic of early-successional stages, showed high dead biomass loads. Our results suggest that the species that tend to retain more dead branches are colonising species that may promote fire in early-successional stages. © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.

Mercury sequestration by rainforests: The influence of microclimate and different successional stages.

PubMed

Teixeira, Daniel C; Lacerda, Luiz D; Silva-Filho, Emmanoel V

2017-02-01

Mercury (Hg) concentrations in tropical forest soils and litter are up to 10 times higher than those from temperate and boreal forests. The majority of Hg that has been stored in tropical soils, as the forest is left intact, could be trapped in deeper layers of soil and only small quantities are exported to water bodies. The quantitative approach to the Hg cycle in tropical forests is uncommon; the South America Atlantic Forest indeed is a hotspot for species conservation and also seems to be for the Hg's cycle. This study reports on a biannual dynamics of Hg through different species assemblage of different successional stages in this biome, based on 24 litter traps used to collect litterfall from 3 different successional stages under a rainforest located at Brazilian Southeast. The mean Hg litterfall flux obtained was 6.1 ± 0.15 μg ha -1  yr -1 , while the mean Hg concentration in litter was 57 ± 16 ng g -1 and the accumulation of Hg via litterfall flux was 34.6 ± 1.2 μg m -2  yr -1 . These inventories are close to those found for tropical areas in the Amazon, but they were lower than those assessed for Atlantic Forest biome studies. These low concentrations are related to the remoteness of the area from pollution sources and probably to the climatic limitation, due to the altitude effects over the forest's eco-physiology. The mercury fluxes found in each different successional stage, correlated with time variations of global radiation, suggesting a mandatory role of the forest primary production over Hg deposition to the soil. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sustaining Young Forest Communities: Ecology and Management of Early Successional Habitats in the Central Hardwood Region, USA

Treesearch

Cathryn H. Greenberg; Beverly S. Collins; Frank R. Thompson III

2011-01-01

There is a rising concern among natural resource scientists and managers about decline of the many plant and animal species associated with early ­successional habitats. There is no concise definition of early successional habitats. However, all have a well developed ground cover or shrub and young tree component, lack a closed, mature tree canopy, and are created or...

An incremental economic analysis of establishing early successional habitat for biodiversity

Treesearch

Slayton W. Hazard-Daniel; Patrick Hiesl; Susan C. Loeb; Thomas J. Straka

2017-01-01

Early successional habitat (ESH) is an important component of natural landscapes and is crucial to maintaining biodiversity. ESH also impacts endangered species. The extent of forest disturbances resulting in ESH has been diminishing, and foresters have developed timber management regimes using standard silvicultural techniques that...

Introduction: what are early successional habitats, why are they important, and how can they be sustained? Chapter 1.

Treesearch

Cathryn H. Greenberg; Beverly S. Collins; Frank R., III Thompson; William H. McNab

2011-01-01

There is a rising concern among natural resource scientists and managers about decline of the many plant and animal species associated with early successional habitats. There is no concise definition of early successional habitats. However, all have a well developed ground cover or shrub and young tree component, lack a closed, mature tree canopy, and are created or...

Predicting forest successional stages using mutitemporal Landsat imagery with forest inventory and analysis data

Treesearch

Weiguo Liu; Conghe Song; Todd A. Schroeder; Warren B. Cohen

2008-01-01

Forest succession is an important ecological process that has profound biophysical, biological and biogeochemical implications in terrestrial ecosystems. Therefore, information on forest successional stages over an extensive forested landscape is crucial for us to understand ecosystem processes, such as carbon assimilation and energy interception. This study explored...

Family richness and biomass of understory invertebrates in early and late successional habitats of northern New Hampshire

Treesearch

Matthew K. Wilson; Winsor H. Lowe; Keith Nislow

2014-01-01

In the northeastern United States, many vertebrate species rely on early successional forest habitats (ESHs). ESHs may also support higher invertebrate diversity and abundance than late successional habitats (LSHs). We assessed the differences in family-level richness and biomass of understory terrestrial invertebrates during the summer season in paired ESH (3-7 years...

The vertical development of early successional forests in northern Michigan, USA

Treesearch

Kurt S. Pregitzer; Brain J. Palik

1993-01-01

1. Studies have shown that differences in height growth rates are characteristic of tree species that differ in understory tolerance and relative successional status. Less-tolerant species have greater juvenile height growth rates than more-tolerant species and thus, in a mixed-species forest, the former gain an early competitive advantage after a stand-initiating...

Demographic variation across successional stages and their effects on the population dynamics of the neotropical palm Euterpe precatoria.

PubMed

Otárola, Mauricio Fernández; Avalos, Gerardo

2014-06-01

• Premise of the study: Environmental heterogeneity is a strong selective force shaping adaptation and population dynamics across temporal and spatial scales. Natural and anthropogenic gradients influence the variation of environmental and biotic factors, which determine population demography and dynamics. Successional gradients are expected to influence demographic parameters, but the relationship between these gradients and the species life history, habitat requirements, and degree of variation in demographic traits remains elusive.• Methods: We used the palm Euterpe precatoria to test the effect of successional stage on plant demography within a continuous population. We calculated demographic parameters for size stages and performed matrix analyses to investigate the demographic variation within primary and secondary forests of La Selva, Costa Rica.• Key results: We observed differences in mortality and recruitment of small juveniles between primary and secondary forests. Matrix models described satisfactorily the chronosequence of population changes, which were characterized by high population growth rate in disturbed areas, and decreased growth rate in old successional forests until reaching stability.• Conclusions: Different demographic parameters can be expressed in contiguous subpopulations along a gradient of successional stages with important consequences for population dynamics. Demographic variation superimposed on these gradients contributes to generate subpopulations with different demographic composition, density, and ecological properties. Therefore, the effects of spatial variation must be reconsidered in the design of demographic analyses of tropical palms, which are prime examples of subtle local adaptation. These considerations are crucial in the implementation of management plans for palm species within spatially complex and heterogeneous tropical landscapes. © 2014 Botanical Society of America, Inc.

Mapping Successional Stages in a Wet Tropical Forest Using Landsat ETM+ and Forest Inventory Data

NASA Technical Reports Server (NTRS)

Goncalves, Fabio G.; Yatskov, Mikhail; dos Santos, Joao Roberto; Treuhaft, Robert N.; Law, Beverly E.

2010-01-01

In this study, we test whether an existing classification technique based on the integration of Landsat ETM+ and forest inventory data enables detailed characterization of successional stages in a wet tropical forest site. The specific objectives were: (1) to map forest age classes across the La Selva Biological Station in Costa Rica; and (2) to quantify uncertainties in the proposed approach in relation to field data and existing vegetation maps. Although significant relationships between vegetation height entropy (a surrogate for forest age) and ETM+ data were detected, the classification scheme tested in this study was not suitable for characterizing spatial variation in age at La Selva, as evidenced by the error matrix and the low Kappa coefficient (12.9%). Factors affecting the performance of the classification at this particular study site include the smooth transition in vegetation structure between intermediate and advanced successional stages, and the low sensitivity of NDVI to variations in vertical structure at high biomass levels.

Management of early-successional communities in central hardwood forests: with special emphasis on the ecology and management of oaks, ruffed grouse, and forest songbirds.

Treesearch

Frank R. III Thompson; Daniel R. Dessecker

1997-01-01

Describes the history, ecology, and silviculture of central hardwood forests and the status and ecology of early-successional forest songbirds and ruffed grouse. Concludes with management guidelines for early-successional communities in central hardwood forests.

Variation In Early-Successional Habitat Use Among Independent Juvenile Forest Breeding Birds

Treesearch

Alicia D. Burke; Frank R. Thompson; John Faaborg

2017-01-01

Adults and juveniles of some forest breeding birds shift habitat use during the post breeding season from late to early successional forest. Juveniles of smaller passerine species are difficult to radio-track, and there is limited information on their habitat preferences, especially once they become older and independent. We determined if independent hatch-year birds...

Spatial characteristics of early successional habitat across the Upper Great Lakes states

Treesearch

Brian G. Tavernia; Mark D. Nelson; James D. Garner; Charles H. (Hobie) Perry

2016-01-01

Creation and management of early successional forest (ESF) is needed to halt and reverse declines of bird species dependent on pioneering plant species or young forests. ESF-dependent bird species require specific structural forest classes and are sensitive to forest age (a surrogate for forest structure), patch size, proximity to patch edges, and the juxtaposition of...

Presence and Expression of Microbial Genes Regulating Soil Nitrogen Dynamics Along the Tanana River Successional Sequence

NASA Astrophysics Data System (ADS)

Boone, R. D.; Rogers, S. L.

2004-12-01

We report on work to assess the functional gene sequences for soil microbiota that control nitrogen cycle pathways along the successional sequence (willow, alder, poplar, white spruce, black spruce) on the Tanana River floodplain, Interior Alaska. Microbial DNA and mRNA were extracted from soils (0-10 cm depth) for amoA (ammonium monooxygenase), nifH (nitrogenase reductase), napA (nitrate reductase), and nirS and nirK (nitrite reductase) genes. Gene presence was determined by amplification of a conserved sequence of each gene employing sequence specific oligonucleotide primers and Polymerase Chain Reaction (PCR). Expression of the genes was measured via nested reverse transcriptase PCR amplification of the extracted mRNA. Amplified PCR products were visualized on agarose electrophoresis gels. All five successional stages show evidence for the presence and expression of microbial genes that regulate N fixation (free-living), nitrification, and nitrate reduction. We detected (1) nifH, napA, and nirK presence and amoA expression (mRNA production) for all five successional stages and (2) nirS and amoA presence and nifH, nirK, and napA expression for early successional stages (willow, alder, poplar). The results highlight that the existing body of previous process-level work has not sufficiently considered the microbial potential for a nitrate economy and free-living N fixation along the complete floodplain successional sequence.

Ecophysiological characterization of early successional biological soil crusts in heavily human-impacted areas

NASA Astrophysics Data System (ADS)

Szyja, Michelle; Büdel, Burkhard; Colesie, Claudia

2018-04-01

Ecophysiological characterizations of photoautotrophic communities are not only necessary to identify the response of carbon fixation related to different climatic factors, but also to evaluate risks connected to changing environments. In biological soil crusts (BSCs), the description of ecophysiological features is difficult, due to the high variability in taxonomic composition and variable methodologies applied. Especially for BSCs in early successional stages, the available datasets are rare or focused on individual constituents, although these crusts may represent the only photoautotrophic component in many heavily disturbed ruderal areas, such as parking lots or building areas with increasing surface area worldwide. We analyzed the response of photosynthesis and respiration to changing BSC water contents (WCs), temperature and light in two early successional BSCs. We investigated whether the response of these parameters was different between intact BSC and the isolated dominating components. BSCs dominated by the cyanobacterium Nostoc commune and dominated by the green alga Zygogonium ericetorum were examined. A major divergence between the two BSCs was their absolute carbon fixation rate on a chlorophyll basis, which was significantly higher for the cyanobacterial crust. Nevertheless, independent of species composition, both crust types and their isolated organisms had convergent features such as high light acclimatization and a minor and very late-occurring depression in carbon uptake at water suprasaturation. This particular setup of ecophysiological features may enable these communities to cope with a high variety of climatic stresses and may therefore be a reason for their success in heavily disturbed areas with ongoing human impact. However, the shape of the response was different for intact BSC compared to separated organisms, especially in absolute net photosynthesis (NP) rates. This emphasizes the importance of measuring intact BSCs under natural

Estimating plant biomass in early-successional subtropical vegetation using a visual obstruction technique

Treesearch

Genie M. Fleming; Joseph M. Wunderle; David N. Ewert; Joseph O' Brien

2014-01-01

Aim: Non-destructive methods for quantifying above-ground plant biomass are important tools in many ecological studies and management endeavours, but estimation methods can be labour intensive and particularly difficult in structurally diverse vegetation types. We aimed to develop a low-cost, but reasonably accurate, estimation technique within early-successional...

Comparative hydraulic architecture of tropical tree species representing a range of successional stages and wood density

Treesearch

Katherine A. McCulloh; Frederick C. Meinzer; John S. Sperry; Barbara Lachenbruch; Steven L. Voelker; David R. Woodruff; Jean-Christophe Domec

2011-01-01

Plant hydraulic architecture (PHA) has been linked to water transport sufficiency, photosynthetic rates, growth form and attendant carbon allocation. Despite its influence on traits central to conferring an overall competitive advantage in a given environment, few studies have examined whether key aspects of PHA are indicative of successional stage, especially within...

Bryophyte-dominated biological soil crusts mitigate soil erosion in an early successional Chinese subtropical forest

NASA Astrophysics Data System (ADS)

Seitz, Steffen; Nebel, Martin; Goebes, Philipp; Käppeler, Kathrin; Schmidt, Karsten; Shi, Xuezheng; Song, Zhengshan; Webber, Carla L.; Weber, Bettina; Scholten, Thomas

2017-12-01

This study investigated the development of biological soil crusts (biocrusts) in an early successional subtropical forest plantation and their impact on soil erosion. Within a biodiversity and ecosystem functioning experiment in southeast China (biodiversity and ecosystem functioning (BEF) China), the effect of these biocrusts on sediment delivery and runoff was assessed within micro-scale runoff plots under natural rainfall, and biocrust cover was surveyed over a 5-year period. Results showed that biocrusts occurred widely in the experimental forest ecosystem and developed from initial light cyanobacteria- and algae-dominated crusts to later-stage bryophyte-dominated crusts within only 3 years. Biocrust cover was still increasing after 6 years of tree growth. Within later-stage crusts, 25 bryophyte species were determined. Surrounding vegetation cover and terrain attributes significantly influenced the development of biocrusts. Besides high crown cover and leaf area index, the development of biocrusts was favoured by low slope gradients, slope orientations towards the incident sunlight and the altitude of the research plots. Measurements showed that bryophyte-dominated biocrusts strongly decreased soil erosion, being more effective than abiotic soil surface cover. Hence, their significant role in mitigating sediment delivery and runoff generation in mesic forest environments and their ability to quickly colonise soil surfaces after disturbance are of particular interest for soil erosion control in early-stage forest plantations.

Do mature forest birds prefer early-successional habitat during the post-fledging period?

Treesearch

Carlin C. Chandler; David I. King; Richard B. Chandler

2012-01-01

Recent studies have highlighted the importance of the post-fledging period to bird populations, suggesting that the importance of this portion of the life cycle is equal to or greater than the nesting period. Nevertheless, few studies have compared abundance of forest nesting species between mature forest and early-successional habitats while controlling for...

Overwinter survival of neotropical migratory birds in early successional and mature tropical forests

USGS Publications Warehouse

Conway, C.J.; Powell, G.V.N.; Nichols, J.D.

1995-01-01

Many Neotropical migratory species inhabit both mature and early successional forest on their wintering grounds, yet comparisons of survival rates between habitats are lacking. Consequently, the factors affecting habitat suitability for Neotropical migrants and the potential effects of tropical deforestation on migrants are not well understood. We estimated over-winter survival and capture probabilities of Wood Thrush (Hylocichla mustelina), Ovenbird (Seiurus aurocapillus), Hooded Warbler (Wilsonia citrina), and Kentucky Warbler (Oporomis formosus) inhabiting two common tropical habitat types, mature and early-successional forest. Our results suggest that large differences (for example, ratio of survival rates (gamma) < 0.85) in overwinter survival between these habitats do not exist for any of these species. Age ratios did not differ between habitats, but males were more common in forest habitats and females more common in successional habitats for Hooded Warblers and Kentucky Warblers. Future research on overwinter survival should address the need for age- and sex-specific survival estimates before we can draw strong conclusions regarding winter habitat suitability. Our estimates of over-winter survival extrapolated to annual survival rates that were generally lower than previous estimates of annual survival of migratory birds. Capture probability differed between habitats for Kentucky Warblers, but our results provide strong evidence against large differences in capture probability between habitats for Wood Thrush, Hooded Warblers, and Ovenbirds. We found no temporal or among site differences in survival or capture probability for any of the four species. Additional research is needed to examine the effects of winter habitat use on survival during migration and between-winter survival.

[Effect of climate change on net primary productivity of Korean pine (Pinus koraiensis) at different successional stages of broad-leaved Korean pine forest].

PubMed

Qiu, Yang; Gao, Lu-Shuang; Zhang, Xue; Guo, Jing; Ma, Zhi-Yuan

2014-07-01

Pinus koraiensis in broad-leaved Korean pine forests of Changbai Mountain at different successional stages (secondary poplar-birch forest, secondary coniferous and broad-leaved forest and the primitive Korean pine forest) were selected in this paper as the research objects. In this research, the annual growth of net primary productivity (NPP) (1921-2006) of P. koraiensis was obtained by combining the tree-ring chronology and relative growth formulae, the correlation between NPP of P. koraiensis and climatic factors was developed, and the annual growth of NPP of P. koraiensis at different successional stages in relation to climatic variation within different climate periods were analyzed. The results showed that, in the research period, the correlations between climatic factors and NPP of P. koraiensis at different successional stages were different. With increasing the temperature, the correlations between NPP of P. koraiensis in the secondary poplar-birch forest and the minimum temperatures of previous and current growing seasons changed from being significantly negative to being significantly positive. The positive correlation between NPP of P. koraiensis in the secondary coniferous and broad-leaved forest and the minimum temperature in current spring changed into significantly positive correlation between NPP of P. koraiensis and the temperatures in previous and current growing seasons. The climatic factors had a stronger hysteresis effect on NPP of P. koraiensis in the secondary coniferous and broad-leaved forest, but NPP of P. koraiensis in the primitive Korean pine forest had weaker correlation with temperature but stronger positive correlation with the precipitation of previous growing season. The increases of minimum and mean temperatures were obvious, but no significant variations of the maximum temperature and precipitation were observed at our site. The climatic variation facilitated the increase of the NPP of P. koraiensis in the secondary poplar

An evaluation of powerline rights-of-way as habitat for early-successional shrubland birds

Treesearch

David I. King; Bruce E. Byers

2002-01-01

Recent population declines among bird species that breed in early-successional shrubland habitats in the eastern United States have been associated with declines in habitat availability. Forest succession has eliminated shrublands in many locations, but powerline rights-of-way constitute a potential reservoir of shrubland habitat for birds. We studied 2 populations of...

The Effect of Local and Landscape-Level Characteristics on the Abundance of Forest Birds in Early-Successional Habitats during the Post-Fledging Season in Western Massachusetts

PubMed Central

Labbe, Michelle A.; King, David I.

2014-01-01

Many species of mature forest-nesting birds (“forest birds”) undergo a pronounced shift in habitat use during the post-fledging period and move from their forest nesting sites into areas of early-successional vegetation. Mortality is high during this period, thus understanding the resource requirements of post-fledging birds has implications for conservation. Efforts to identify predictors of abundance of forest birds in patches of early-successional habitats have so far been equivocal, yet these previous studies have primarily focused on contiguously forested landscapes and the potential for landscape-scale influences in more fragmented and modified landscapes is largely unknown. Landscape composition can have a strong influence on the abundance and productivity of forest birds during the nesting period, and could therefore affect the number of forest birds in the landscape available to colonize early-successional habitats during the post-fledging period. Therefore, the inclusion of landscape characteristics should increase the explanatory power of models of forest bird abundance in early-successional habitat patches during the post-fledging period. We examined forest bird abundance and body condition in relation to landscape and habitat characteristics of 15 early-successional sites during the post-fledging season in Massachusetts. The abundance of forest birds was influenced by within-patch habitat characteristics, however the explanatory power of these models was significantly increased by the inclusion of landscape fragmentation and the abundance of forest birds in adjacent forest during the nesting period for some species and age groups. Our findings show that including factors beyond the patch scale can explain additional variation in the abundance of forest birds in early-successional habitats during the post-fledging period. We conclude that landscape composition should be considered when siting early-successional habitat to maximize its benefit to

The effect of local and landscape-level characteristics on the abundance of forest birds in early-successional habitats during the post-fledging season in western Massachusetts.

PubMed

Labbe, Michelle A; King, David I

2014-01-01

Many species of mature forest-nesting birds ("forest birds") undergo a pronounced shift in habitat use during the post-fledging period and move from their forest nesting sites into areas of early-successional vegetation. Mortality is high during this period, thus understanding the resource requirements of post-fledging birds has implications for conservation. Efforts to identify predictors of abundance of forest birds in patches of early-successional habitats have so far been equivocal, yet these previous studies have primarily focused on contiguously forested landscapes and the potential for landscape-scale influences in more fragmented and modified landscapes is largely unknown. Landscape composition can have a strong influence on the abundance and productivity of forest birds during the nesting period, and could therefore affect the number of forest birds in the landscape available to colonize early-successional habitats during the post-fledging period. Therefore, the inclusion of landscape characteristics should increase the explanatory power of models of forest bird abundance in early-successional habitat patches during the post-fledging period. We examined forest bird abundance and body condition in relation to landscape and habitat characteristics of 15 early-successional sites during the post-fledging season in Massachusetts. The abundance of forest birds was influenced by within-patch habitat characteristics, however the explanatory power of these models was significantly increased by the inclusion of landscape fragmentation and the abundance of forest birds in adjacent forest during the nesting period for some species and age groups. Our findings show that including factors beyond the patch scale can explain additional variation in the abundance of forest birds in early-successional habitats during the post-fledging period. We conclude that landscape composition should be considered when siting early-successional habitat to maximize its benefit to forest

Utilization of lightflecks by seedlings of five dominant tree species of different subtropical forest successional stages under low-light growth conditions.

PubMed

Zhang, Q; Chen, Y J; Song, L Y; Liu, N; Sun, L L; Peng, C L

2012-05-01

We selected five typical tree species, including one early-successional species (ES) Pinus massoniana Lamb., two mid-successional species (MS) Schima superba Gardn. et Champ. and Castanopsis fissa (Champ. ex Benth.) Rehd. et Wils. and two late-successional species (LS) Cryptocarya concinna Hance. and Acmena acuminatissima (BI.) Merr et Perry., which represent the plants at three successional periods in Dinghushan subtropical forest succession of southern China. Potted seedlings of the five species were grown under 12% of full sunlight for 36 months. The ES and MS showed the slowest and fastest responses to lightflecks, respectively, which correlated with the rate of stomatal opening. In contrast to P. massoniana and C. concinna, the other three species exhibited a high induction loss. Early-successional species showed the lowest specific leaf area and chlorophyll content, the highest photosynthetic capacity (A(max)) and respiratory carbon losses (R(d)). Compared with ES and MS, LS showed lower A(max) and R(d). The five tree species showed a similar chlorophyll a/b ratio after long-term low-light adaptations. On the other hand, LS had a relatively higher de-epoxidation state to protect themselves from excess light during lightflecks. Our results indicated that (i) slower responses to lightflecks could partially explain why ES species could not achieve seedling regeneration in low-light conditions; (ii) fast responses to lightflecks could partially explain why MS species could achieve seedling regeneration in low-light conditions; and (iii) smaller respiratory carbon losses might confer on the LS species a competitive advantage in low-light conditions.

Anthropogenic Habitats Facilitate Dispersal of an Early Successional Obligate: Implications for Restoration of an Endangered Ecosystem.

PubMed

Amaral, Katrina E; Palace, Michael; O'Brien, Kathleen M; Fenderson, Lindsey E; Kovach, Adrienne I

2016-01-01

Landscape modification and habitat fragmentation disrupt the connectivity of natural landscapes, with major consequences for biodiversity. Species that require patchily distributed habitats, such as those that specialize on early successional ecosystems, must disperse through a landscape matrix with unsuitable habitat types. We evaluated landscape effects on dispersal of an early successional obligate, the New England cottontail (Sylvilagus transitionalis). Using a landscape genetics approach, we identified barriers and facilitators of gene flow and connectivity corridors for a population of cottontails in the northeastern United States. We modeled dispersal in relation to landscape structure and composition and tested hypotheses about the influence of habitat fragmentation on gene flow. Anthropogenic and natural shrubland habitats facilitated gene flow, while the remainder of the matrix, particularly development and forest, impeded gene flow. The relative influence of matrix habitats differed between study areas in relation to a fragmentation gradient. Barrier features had higher explanatory power in the more fragmented site, while facilitating features were important in the less fragmented site. Landscape models that included a simultaneous barrier and facilitating effect of roads had higher explanatory power than models that considered either effect separately, supporting the hypothesis that roads act as both barriers and facilitators at all spatial scales. The inclusion of LiDAR-identified shrubland habitat improved the fit of our facilitator models. Corridor analyses using circuit and least cost path approaches revealed the importance of anthropogenic, linear features for restoring connectivity between the study areas. In fragmented landscapes, human-modified habitats may enhance functional connectivity by providing suitable dispersal conduits for early successional specialists.

Anthropogenic Habitats Facilitate Dispersal of an Early Successional Obligate: Implications for Restoration of an Endangered Ecosystem

PubMed Central

Amaral, Katrina E.; Palace, Michael; O’Brien, Kathleen M.; Fenderson, Lindsey E.; Kovach, Adrienne I.

2016-01-01

Landscape modification and habitat fragmentation disrupt the connectivity of natural landscapes, with major consequences for biodiversity. Species that require patchily distributed habitats, such as those that specialize on early successional ecosystems, must disperse through a landscape matrix with unsuitable habitat types. We evaluated landscape effects on dispersal of an early successional obligate, the New England cottontail (Sylvilagus transitionalis). Using a landscape genetics approach, we identified barriers and facilitators of gene flow and connectivity corridors for a population of cottontails in the northeastern United States. We modeled dispersal in relation to landscape structure and composition and tested hypotheses about the influence of habitat fragmentation on gene flow. Anthropogenic and natural shrubland habitats facilitated gene flow, while the remainder of the matrix, particularly development and forest, impeded gene flow. The relative influence of matrix habitats differed between study areas in relation to a fragmentation gradient. Barrier features had higher explanatory power in the more fragmented site, while facilitating features were important in the less fragmented site. Landscape models that included a simultaneous barrier and facilitating effect of roads had higher explanatory power than models that considered either effect separately, supporting the hypothesis that roads act as both barriers and facilitators at all spatial scales. The inclusion of LiDAR-identified shrubland habitat improved the fit of our facilitator models. Corridor analyses using circuit and least cost path approaches revealed the importance of anthropogenic, linear features for restoring connectivity between the study areas. In fragmented landscapes, human-modified habitats may enhance functional connectivity by providing suitable dispersal conduits for early successional specialists. PMID:26954014

Productivity of early successional shrubland birds in clearcuts and groupcuts in an eastern deciduous forest

Treesearch

David I. King; Richard M. DeGraaf; Curtice R. Griffin

2001-01-01

Uneven-aged forest management has been advocated as a silvicultural practice because of concerns about the negative effects of even-aged management on birds that dwell in mature forests. Recent evidence, however, indicates that in the northeastern United States, bird species that inhabit early successional habitats may be experiencing more widespread declines than...

Dynamics, chemical properties and bioavailability of DOC in an early successional catchment

NASA Astrophysics Data System (ADS)

Risse-Buhl, U.; Hagedorn, F.; Dümig, A.; Gessner, M. O.; Schaaf, W.; Nii-Annang, S.; Gerull, L.; Mutz, M.

2013-01-01

The dynamics of dissolved organic carbon (DOC) have been intensively studied in mature ecosystems, but little is known about DOC dynamics and the significance of DOC as a substrate for microbial activity in early-successional catchments. We determined the concentration, chemical composition, source, radiocarbon age, and bioavailability of DOC along the hydrological flow path from soil solution to a downstream pond in a recently constructed catchment (Chicken Creek Catchment, Germany). Soil solution, upwelling ground water, subsurface water in an alluvial fan, and pond water all had high DOC concentrations (averages of 6.0-11.6 mg DOC L-1), despite small carbon stocks in either vegetation or soil of the early-successional catchment. The mean 14C age of DOC in upwelling ground water was 2600 to 2800 yr. Solid-state CPMAS 13C NMR revealed a higher proportion of aromatic compounds (32%) and a lower proportion of carbohydrates (33%) in upwelling ground water than in pond water (18% and 45%, respectively). The 14C age and 13C NMR spectra suggest that DOC was partly mobilized from charred organic matter of the Quaternary substrate. In an experimental 70-days incubation experiment, 20% of the total DOC was found to be bioavailable, irrespective of the water type. Origin of microbial communities (enriched from soil, stream sediment or pond water) had only marginal effects on overall DOC utilization. Overall, these data suggest that the old DOC can support microbial activity during early ecosystem succession to some extent, although the largest fraction is recalcitrant DOC that is exported from the catchment once it has been mobilized.

Use of group-selection and seed-tree cuts by three early-successional migratory species in Arkansas

Treesearch

Lynn E. Alterman; James C. Bednarz; Ronald E. Thill

2005-01-01

Silviculture in the Ouachita National Forest in Arkansas and Oklahoma has shifted in recent years from mostly even-aged management to a mix of even- and uneven-aged regeneration systems, including group-selection. Researchers have described presence/absence of early-successional bird species in forest openings created by even- and uneven-aged silviculture, but few have...

Trait Variation Along a Forest Successional Gradient in Dry Tropical Forest, Florida Keys

NASA Astrophysics Data System (ADS)

Subedi, S.; Ross, M. S.

2016-12-01

In most part of South Florida tropical dry forests, the early colonized trees on disturbed uplands are mostly deciduous species cable of surviving for several years after establishment. However, trees in mature forests are generally characterized by a suite of evergreen species, most of which are completely absent in younger stands even in seedling stage. This complete transition from one functional group to another in the course of stand development suggests a distinct change in the underlying environment during the course of succession. Such change in hammock functional groups as a function of the changing environmental drivers during succession in tropical dry forests is unknown and addressing this question may help to understand which drivers of change act as filters that select for and against particular groups of species and traits. In this study, we evaluate number of important functional traits (specific leaf area, wood density, leaf d13C, leaf N:P ratio, and architectural traits such as height, crown dimensions, diameter at breast height) for woody plant species occurring along a successional gradient across three ecological scales, community, species, and individual. A significant change in the overall trait distribution across the successional gradient is found. Intraspecific trait variation within the community is increased with increase in forest age. Most of these traits have shown correlation with stand age and showed preference to a certain environment. Stand age is the most important variable explaining the distribution of community characteristics. It is found that early successional forest are mostly shaped by environmental driven processes, and as forest get older and structurally more complex, they are increasingly shaped by competitively driven processes leading to limiting similarity. This study has shown that the patterns of trait shift can be predictable and can be used to characterize habitats and stage of forest succession in dry tropical

Associations among arbuscular mycorrhizal fungi and seedlings are predicted to change with tree successional status.

PubMed

Bachelot, Benedicte; Uriarte, María; Muscarella, Robert; Forero-Montaña, Jimena; Thompson, Jill; McGuire, Krista; Zimmerman, Jess; Swenson, Nathan G; Clark, James S

2018-03-01

Arbuscular mycorrhizal (AM) fungi in the soil may influence tropical tree dynamics and forest succession. The mechanisms are poorly understood, because the functional characteristics and abundances of tree species and AM fungi are likely to be codependent. We used generalized joint attribute modeling to evaluate if AM fungi are associated with three forest community metrics for a sub-tropical montane forest in Puerto Rico. The metrics chosen to reflect changes during forest succession are the abundance of seedlings of different successional status, the amount of foliar damage on seedlings of different successional status, and community-weighted mean functional trait values (adult specific leaf area [SLA], adult wood density, and seed mass). We used high-throughput DNA sequencing to identify fungal operational taxonomic units (OTUs) in the soil. Model predictions showed that seedlings of mid- and late-successional species had less leaf damage when the 12 most common AM fungi were abundant compared to when these fungi were absent. We also found that seedlings of mid-successional species were predicted to be more abundant when the 12 most common AM fungi were abundant compared to when these fungi were absent. In contrast, early-successional tree seedlings were predicted to be less abundant when the 12 most common AM fungi were abundant compared to when these fungi were absent. Finally, we showed that, among the 12 most common AM fungi, different AM fungi were correlated with functional trait characteristics of early- or late-successional species. Together, these results suggest that early-successional species might not rely as much as mid- and late-successional species on AM fungi, and AM fungi might accelerate forest succession. © 2017 by the Ecological Society of America.

Silvicultural options for early-successional stands in Maine: 6-year results of the Silvicultural Intensity and Species Composition Experiment

Treesearch

Andrew S. Nelson; Robert G. Wagner; Mike R. Saunders

2014-01-01

The Silvicultural Intensity and Species Composition (SIComp) experiment was installed in 2003 on a recently clearcut mixedwood site within the Penobscot Experimental Forest in east-central Maine. This study was initiated because the response of early-successional stands to various intensities of silviculture was poorly understood in the region. The goal of SIComp is to...

Root colonization and spore abundance of arbuscular mycorrhizal fungi in distinct successional stages from an Atlantic rainforest biome in southern Brazil.

PubMed

Zangaro, Waldemar; Rostirola, Leila Vergal; de Souza, Priscila Bochi; de Almeida Alves, Ricardo; Lescano, Luiz Eduardo Azevedo Marques; Rondina, Artur Berbel Lírio; Nogueira, Marco Antonio; Carrenho, Rosilaine

2013-04-01

The influence of plant functional groups and moderate seasonality on arbuscular mycorrhizal (AM) fungal status (root colonization and spore density) was investigated during 13 consecutive months in a chronosequence of succession in southern Brazil, consisting of grassland field, scrub vegetation, secondary forest and mature forest, in a region of transition from tropical to subtropical zones. AM root colonization and spore density decreased with advancing succession and were highest in early successional sites with grassland and scrub vegetation, intermediary in the secondary forest and lowest in the mature forest. They were little influenced by soil properties, but were sufficiently influenced by the fine root nutrient status and fine root traits among different functional plant groups. AM root colonization and spore density were higher during the favourable plant growth season (spring and summer) than during the less favourable plant growth season (autumn and winter). Spore density displayed significant seasonal variation at all sites, whilst root colonization displayed significant seasonal variation in grassland, scrub and secondary forest, but not in mature forest. The data suggest that (1) different plant functional groups display different relationships with AM fungi, influencing their abundance differentially; (2) plant species from early successional phases are more susceptible to AM root colonization and maintain higher AM sporulation than late successional species; (3) fine root traits and nutrient status influence these AM fungal attributes; and (4) higher AM spore production and root colonization is associated with the season of higher light incidence and temperature, abundant water in soil and higher plant metabolic activity.

Dependence of soil respiration on soil temperature and soil moisture in successional forests in Southern China

USGS Publications Warehouse

Tang, X.-L.; Zhou, G.-Y.; Liu, S.-G.; Zhang, D.-Q.; Liu, S.-Z.; Li, Ji; Zhou, C.-Y.

2006-01-01

The spatial and temporal variations in soil respiration and its relationship with biophysical factors in forests near the Tropic of Cancer remain highly uncertain. To contribute towards an improvement of actual estimates, soil respiration rates, soil temperature, and soil moisture were measured in three successional subtropical forests at the Dinghushan Nature Reserve (DNR) in southern China from March 2003 to February 2005. The overall objective of the present study was to analyze the temporal variations of soil respiration and its biophysical dependence in these forests. The relationships between biophysical factors and soil respiration rates were compared in successional forests to test the hypothesis that these forests responded similarly to biophysical factors. The seasonality of soil respiration coincided with the seasonal climate pattern, with high respiration rates in the hot humid season (April-September) and with low rates in the cool dry season (October-March). Soil respiration measured at these forests showed a clear increasing trend with the progressive succession. Annual mean (±SD) soil respiration rate in the DNR forests was (9.0 ± 4.6) Mg CO2-C/hm2per year, ranging from (6.1 ± 3.2) Mg CO2-C/hm2per year in early successional forests to (10.7 ± 4.9) Mg CO2-C/hm2 per year in advanced successional forests. Soil respiration was correlated with both soil temperature and moisture. The T/M model, where the two biophysical variables are driving factors, accounted for 74%-82% of soil respiration variation in DNR forests. Temperature sensitivity decreased along progressive succession stages, suggesting that advanced-successional forests have a good ability to adjust to temperature. In contrast, moisture increased with progressive succession processes. This increase is caused, in part, by abundant respirators in advanced-successional forest, where more soil moisture is needed to maintain their activities.

Seed dispersal by wind, birds, and bats between Philippine montane rainforest and successional vegetation.

PubMed

Ingle, Nina M R

2003-01-01

In the moist Neotropics, vertebrate frugivores have a much greater role in the dispersal of forest and successional woody plants than wind, and bats rather than birds play the dominant role in dispersing early successional species. I investigated whether these patterns also occurred in a Philippine montane rainforest and adjacent successional vegetation. I also asked whether seed mass was related to probability of dispersal between habitats. A greater number of woody species and stems in the forest produced vertebrate-dispersed seeds than wind-dispersed seeds. Although input of forest seeds into the successional area was dominated by vertebrate-dispersed seeds in terms of species richness, wind-dispersed seeds landed in densities 15 times higher. Frugivorous birds dispersed more forest seeds and species into the successional area than bats, and more successional seeds and species into the forest. As expected, seed input declined with distance from source habitat. Low input of forest seeds into the successional area at the farthest distance sampled, 40 m from forest edge, particularly for vertebrate-dispersed seeds, suggests very limited dispersal out of forest even into a habitat in which woody successional vegetation provides perches and fruit resources. For species of vertebrate-dispersed successional seeds, probability of dispersal into forest declined significantly with seed mass.

Spatial variation in fish assemblages across a beaver-influenced successional landscape

USGS Publications Warehouse

Schlosser, I.J.; Kallemeyn, L.W.

2000-01-01

Beavers are increasingly viewed as “ecological engineers,” having broad effects on physical, chemical, and biological attributes of north-temperate landscapes. We examine the influence of both local successional processes associated with beaver activity and regional geomorphic boundaries on spatial variation in fish assemblages along the Kabetogama Peninsula in Voyageurs National Park, northern Minnesota, USA. Fish abundance and species richness exhibited considerable variation among drainages along the peninsula. Geological barriers to fish dispersal at outlets of some drainages has reduced fish abundance and species richness. Fish abundance and species richness also varied within drainages among local environments associated with beaver pond succession. Fish abundance was higher in upland ponds than in lowland ponds, collapsed ponds, or streams, whereas species richness was highest in collapsed ponds and streams. Cluster analyses based on fish abundance at sites classified according to successional environment indicated that four species (northern redbelly dace, Phoxinus eos; brook stickleback, Culaea inconstans; finescale dace, P. neogaeus; and fathead minnow, Pimephales promelas), were predominant in all successional environments. Several less abundant species were added in collapsed ponds and streams, with smaller size classes of large lake species (e.g., black crappie, Pomoxis nigromaculatus; smallmouth bass, Micropertus dolomieui; yellow perch, Perca flavescens; and burbot, Lota lota) being a component of these less abundant species. The addition of smaller size classes of large lake species indicates that dispersal of early life-history stages from Kabetogama Lake played a role in determining the species richness and composition of less abundant species in successional environments on the peninsula. Furthermore, collapsed-pond and stream environments closer to Kabetogama Lake had higher species richness than similar successional sites located farther

Extinction risk in successional landscapes subject to catastrophic disturbances.

Treesearch

David Boughton; Urmila Malvadkar

2002-01-01

We explore the thesis that stochasticity in successional-disturbance systems can be an agent of species extinction. The analysis uses a simple model of patch dynamics for seral stages in an idealized landscape; each seral stage is assumed to support a specialist biota. The landscape as a whole is characterized by a mean patch birth rate, mean patch size, and mean...

Understanding landowner intentions to create early successional forest habitat in the northeastern United States

USGS Publications Warehouse

Dayer, Ashley A.; Stedman, Richard C.; Allred, Shorna B.; Rosenberg, Kenneth V.; Fuller, Angela K.

2016-01-01

Early successional forest habitat (ESH) and associated wildlife species in the northeastern United States are in decline. One way to help create early successional forest conditions is engaging private forest landowners in even-aged forest management because their limited participation may have contributed to declines in ESH for wildlife species of high conservation concern. We applied the reasoned action approach from social psychology to predict intentions of landowners in the 13-county Southern Tier of New York State, USA, to conduct patch-cuts, which is a type of even-aged forest management. We tested the predictive ability of the model using data from a mail survey of landowners conducted from November 2010 to January 2011. Landowner intention to conduct patch-cuts was high (55% of respondents), with attitude being the strongest direct predictor of behavioral intention. Our results suggest that patch-cutting intentions are most likely expressed by landowners who think the behavior is good for their land and wildlife, believe in positive outcomes of land and wildlife management, belong to a game wildlife organization, and have conducted patch-cuts in the past. Strategies to engage more landowners in ESH management will have the highest likelihood of success if outreach efforts focus on influencing behavioral beliefs and subsequently attitudes, possibly working with game wildlife organizations to communicate a unified message for habitat conservation, including the importance of maintaining and creating ESH. Our results demonstrate the importance of social science research to increase the likelihood that conservation targets for declining wildlife species are met. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Species-driven phases and increasing structure in early-successional plant communities.

PubMed

Zaplata, Markus K; Winter, Susanne; Fischer, Anton; Kollmann, Johannes; Ulrich, Werner

2013-01-01

Successional phases describe changes in ecological communities that proceed in steps rather than continuously. Despite their importance for the understanding of ecosystem development, there still exists no reliable definition of phases and no quantitative measure of phase transitions. In order to obtain these data, we investigated primary succession in an artificial catchment (6 ha) in eastern Germany over a period of 6 years. The data set consists of records of plant species and their cover values, and initial substrate properties, both from plots in a regular grid (20 m × 20 m) suitable for spatial data analysis. Community assembly was studied by analyses of species co-occurrence and nestedness. Additionally, we correlated lognormal and log series distributions of species abundance to each community. We here introduce a new general method for detection of successional phases based on the degree of transient spatial homogeneity in the study system. Spatially coherent vegetation patterns revealed nonoverlapping partitions within this sequence of primary succession and were characterized as two distinct ecological phases. Patterns of species co-occurrence were increasingly less random, and hence the importance of demographic stochasticity and neutral community assembly decreased during the study period. Our findings highlight the spatial dimension of successional phases and quantify the degree of change between these steps. They are an element for advancing a more reliable terminology of ecological successions.

Effects of vegetation, corridor width and regional land use on early successional birds on powerline corridors.

PubMed

Askins, Robert A; Folsom-O'Keefe, Corrine M; Hardy, Margaret C

2012-01-01

Powerline rights-of-way (ROWs) often provide habitat for early successional bird species that have suffered long-term population declines in eastern North America. To determine how the abundance of shrubland birds varies with habitat within ROW corridors and with land use patterns surrounding corridors, we ran Poisson regression models on data from 93 plots on ROWs and compared regression coefficients. We also determined nest success rates on a 1-km stretch of ROW. Seven species of shrubland birds were common in powerline corridors. However, the nest success rates for prairie warbler (Dendroica discolor) and field sparrow (Spizella pusilla) were <21%, which is too low to compensate for estimated annual mortality. Some shrubland bird species were more abundant on narrower ROWs or at sites with lower vegetation or particular types of vegetation, indicating that vegetation management could be refined to favor species of high conservation priority. Also, several species were more abundant in ROWs traversing unfragmented forest than those near residential areas or farmland, indicating that corridors in heavily forested regions may provide better habitat for these species. In the area where we monitored nests, brood parasitism by brown-headed cowbirds (Molothrus ater) occurred more frequently close to a residential area. Although ROWs support dense populations of shrubland birds, those in more heavily developed landscapes may constitute sink habitat. ROWs in extensive forests may contribute more to sustaining populations of early successional birds, and thus may be the best targets for habitat management.

Effects of Vegetation, Corridor Width and Regional Land Use on Early Successional Birds on Powerline Corridors

PubMed Central

Askins, Robert A.; Folsom-O'Keefe, Corrine M.; Hardy, Margaret C.

2012-01-01

Powerline rights-of-way (ROWs) often provide habitat for early successional bird species that have suffered long-term population declines in eastern North America. To determine how the abundance of shrubland birds varies with habitat within ROW corridors and with land use patterns surrounding corridors, we ran Poisson regression models on data from 93 plots on ROWs and compared regression coefficients. We also determined nest success rates on a 1-km stretch of ROW. Seven species of shrubland birds were common in powerline corridors. However, the nest success rates for prairie warbler (Dendroica discolor) and field sparrow (Spizella pusilla) were <21%, which is too low to compensate for estimated annual mortality. Some shrubland bird species were more abundant on narrower ROWs or at sites with lower vegetation or particular types of vegetation, indicating that vegetation management could be refined to favor species of high conservation priority. Also, several species were more abundant in ROWs traversing unfragmented forest than those near residential areas or farmland, indicating that corridors in heavily forested regions may provide better habitat for these species. In the area where we monitored nests, brood parasitism by brown-headed cowbirds (Molothrus ater) occurred more frequently close to a residential area. Although ROWs support dense populations of shrubland birds, those in more heavily developed landscapes may constitute sink habitat. ROWs in extensive forests may contribute more to sustaining populations of early successional birds, and thus may be the best targets for habitat management. PMID:22363660

Take me to your leader: does early successional nonhost vegetation spatially inhibit Pissodes strobi (Coleoptera: Curculionidae)?

PubMed

Koopmans, Jordan M; De La Giroday, Honey-Marie C; Lindgren, B Staffan; Aukema, Brian H

2009-08-01

The spatial influences of host and nonhost trees and shrubs on the colonization patterns of white pine weevil Pissodes strobi (Peck) were studied within a stand of planted interior hybrid spruce [Picea glauca (Moench) Voss x Picea engelmannii (Parry) ex Engelm.]. Planted spruce accounted for one third of all trees within the stand, whereas the remaining two thirds were comprised of early-successional nonhost vegetation, such as alder (Alnus spp.), paper birch (Betula papyrifera Marsh.), black cottonwood [Populus balsamifera ssp. trichocarpa (T. Ng.) Brayshaw], lodgepole pine [Pinus contorta (Dougl.) ex Loud.], trembling aspen (Populus tremuloides Michx), willow (Salix spp.), and Canadian buffaloberry [Shepherdia canadensis (L.) Nutt.]. Unlike the spruce trees, nonhost vegetation in the stand was not uniformly distributed. Spatial point process models showed that Canadian buffaloberry, paper birch, black cottonwoood, and trembling aspen had negative associations with damage caused by the weevil, even though the density of the insects' hosts in these areas did not change. Moreover, knowing the locations of these nonhost trees provided as much, or more, inference about the locations of weevil-attacked trees as knowing the locations of suitable or preferred host trees (i.e., those larger in size). Nonhost volatiles, the alteration of soil composition, and overstory shade are discussed as potential explanatory factors for the patterns observed. New research avenues are suggested to determine whether nonhost vegetation in early successional stands might be an additional tool in the management of these insects in commercially important forests.

Limited toxicity of NH(x) pulses on an early and late successional tropical seagrass species: interactions with pH and light level.

PubMed

Christianen, M J A; van der Heide, T; Bouma, T J; Roelofs, J G M; van Katwijk, M M; Lamers, L P M

2011-07-01

Seagrasses have declined at a global scale due to light reduction and toxicity events, caused by eutrophication and increased sediment loading. Although several studies have tested effects of light reduction and toxicants on seagrasses, there is at present no information available on their interacting effects. In a full-factorial 5-day laboratory experiment, we studied short-term interactive effects of light conditions, pH and reduced nitrogen (NH(x)) in the water layer, mimicking pulses of river discharge, on the tropical early successional species Halodule uninervis and the late successional species Thalassia hemprichii. In contrast to recent results reported for the temperate species Zostera marina, increased NH(x) supply did not affect leaf mortality or photochemical efficiency in H. uninervis and in 7 out of 8 treatments for T. hemprichii. However, both tropical species demonstrated striking differences in nitrogen accumulation, free amino acid composition and free NH₃ accumulation. The increase in tissue nitrogen content was two times higher for H. uninervis than for T. hemprichii. Nitrogen stored as free amino acids (especially asparagine) only increased in H. uninervis. High pH only affected T. hemprichii, but only when not shaded, by doubling its free NH₃ concentrations, concomitantly decreasing its photosynthetic efficiency. Our results indicate that the early successional H. uninervis has higher tolerance to high NH(x) loads as compared to the late successional T. hemprichii. H. uninervis was better able to avoid toxic internal NH(x) levels by further assimilating glutamine into asparagine in contrast to T. hemprichii. Moreover, both tropical species seem to cope much better with high NH(x) than the temperate Z. marina. The implications for the distribution and succession of seagrass species under high nutrient loads are discussed. Copyright © 2011 Elsevier B.V. All rights reserved.

Ocean acidification alters early successional coral reef communities and their rates of community metabolism.

PubMed

Noonan, Sam H C; Kluibenschedl, Anna; Fabricius, Katharina E

2018-01-01

Ocean acidification is expected to alter community composition on coral reefs, but its effects on reef community metabolism are poorly understood. Here we document how early successional benthic coral reef communities change in situ along gradients of carbon dioxide (CO2), and the consequences of these changes on rates of community photosynthesis, respiration, and light and dark calcification. Ninety standardised benthic communities were grown on PVC tiles deployed at two shallow-water volcanic CO2 seeps and two adjacent control sites in Papua New Guinea. Along the CO2 gradient, both the upward facing phototrophic and the downward facing cryptic communities changed in their composition. Under ambient CO2, both communities were dominated by calcifying algae, but with increasing CO2 they were gradually replaced by non-calcifying algae (predominantly green filamentous algae, cyanobacteria and macroalgae, which increased from ~30% to ~80% cover). Responses were weaker in the invertebrate communities, however ascidians and tube-forming polychaetes declined with increasing CO2. Differences in the carbonate chemistry explained a far greater amount of change in communities than differences between the two reefs and successional changes from five to 13 months, suggesting community successions are established early and are under strong chemical control. As pH declined from 8.0 to 7.8, rates of gross photosynthesis and dark respiration of the 13-month old reef communities (upper and cryptic surfaces combined) significantly increased by 10% and 20%, respectively, in response to altered community composition. As a consequence, net production remained constant. Light and dark calcification rates both gradually declined by 20%, and low or negative daily net calcification rates were observed at an aragonite saturation state of <2.3. The study demonstrates that ocean acidification as predicted for the end of this century will strongly alter reef communities, and will significantly

Ocean acidification alters early successional coral reef communities and their rates of community metabolism

PubMed Central

Kluibenschedl, Anna; Fabricius, Katharina E.

2018-01-01

Ocean acidification is expected to alter community composition on coral reefs, but its effects on reef community metabolism are poorly understood. Here we document how early successional benthic coral reef communities change in situ along gradients of carbon dioxide (CO2), and the consequences of these changes on rates of community photosynthesis, respiration, and light and dark calcification. Ninety standardised benthic communities were grown on PVC tiles deployed at two shallow-water volcanic CO2 seeps and two adjacent control sites in Papua New Guinea. Along the CO2 gradient, both the upward facing phototrophic and the downward facing cryptic communities changed in their composition. Under ambient CO2, both communities were dominated by calcifying algae, but with increasing CO2 they were gradually replaced by non-calcifying algae (predominantly green filamentous algae, cyanobacteria and macroalgae, which increased from ~30% to ~80% cover). Responses were weaker in the invertebrate communities, however ascidians and tube-forming polychaetes declined with increasing CO2. Differences in the carbonate chemistry explained a far greater amount of change in communities than differences between the two reefs and successional changes from five to 13 months, suggesting community successions are established early and are under strong chemical control. As pH declined from 8.0 to 7.8, rates of gross photosynthesis and dark respiration of the 13-month old reef communities (upper and cryptic surfaces combined) significantly increased by 10% and 20%, respectively, in response to altered community composition. As a consequence, net production remained constant. Light and dark calcification rates both gradually declined by 20%, and low or negative daily net calcification rates were observed at an aragonite saturation state of <2.3. The study demonstrates that ocean acidification as predicted for the end of this century will strongly alter reef communities, and will significantly

Rate of Belowground Carbon Allocation Differs with Successional Habit of Two Afromontane Trees

PubMed Central

Shibistova, Olga; Yohannes, Yonas; Boy, Jens; Richter, Andreas; Wild, Birgit; Watzka, Margarethe; Guggenberger, Georg

2012-01-01

Background Anthropogenic disturbance of old-growth tropical forests increases the abundance of early successional tree species at the cost of late successional ones. Quantifying differences in terms of carbon allocation and the proportion of recently fixed carbon in soil CO2 efflux is crucial for addressing the carbon footprint of creeping degradation. Methodology We compared the carbon allocation pattern of the late successional gymnosperm Podocarpus falcatus (Thunb.) Mirb. and the early successional (gap filling) angiosperm Croton macrostachyus Hochst. es Del. in an Ethiopian Afromontane forest by whole tree 13CO2 pulse labeling. Over a one-year period we monitored the temporal resolution of the label in the foliage, the phloem sap, the arbuscular mycorrhiza, and in soil-derived CO2. Further, we quantified the overall losses of assimilated 13C with soil CO2 efflux. Principal Findings 13C in leaves of C. macrostachyus declined more rapidly with a larger size of a fast pool (64% vs. 50% of the assimilated carbon), having a shorter mean residence time (14 h vs. 55 h) as in leaves of P. falcatus. Phloem sap velocity was about 4 times higher for C. macrostachyus. Likewise, the label appeared earlier in the arbuscular mycorrhiza of C. macrostachyus and in the soil CO2 efflux as in case of P. falcatus (24 h vs. 72 h). Within one year soil CO2 efflux amounted to a loss of 32% of assimilated carbon for the gap filling tree and to 15% for the late successional one. Conclusions Our results showed clear differences in carbon allocation patterns between tree species, although we caution that this experiment was unreplicated. A shift in tree species composition of tropical montane forests (e.g., by degradation) accelerates carbon allocation belowground and increases respiratory carbon losses by the autotrophic community. If ongoing disturbance keeps early successional species in dominance, the larger allocation to fast cycling compartments may deplete soil organic carbon in

Rate of belowground carbon allocation differs with successional habit of two afromontane trees.

PubMed

Shibistova, Olga; Yohannes, Yonas; Boy, Jens; Richter, Andreas; Wild, Birgit; Watzka, Margarethe; Guggenberger, Georg

2012-01-01

Anthropogenic disturbance of old-growth tropical forests increases the abundance of early successional tree species at the cost of late successional ones. Quantifying differences in terms of carbon allocation and the proportion of recently fixed carbon in soil CO(2) efflux is crucial for addressing the carbon footprint of creeping degradation. We compared the carbon allocation pattern of the late successional gymnosperm Podocarpus falcatus (Thunb.) Mirb. and the early successional (gap filling) angiosperm Croton macrostachyus Hochst. es Del. in an Ethiopian Afromontane forest by whole tree (13)CO(2) pulse labeling. Over a one-year period we monitored the temporal resolution of the label in the foliage, the phloem sap, the arbuscular mycorrhiza, and in soil-derived CO(2). Further, we quantified the overall losses of assimilated (13)C with soil CO(2) efflux. (13)C in leaves of C. macrostachyus declined more rapidly with a larger size of a fast pool (64% vs. 50% of the assimilated carbon), having a shorter mean residence time (14 h vs. 55 h) as in leaves of P. falcatus. Phloem sap velocity was about 4 times higher for C. macrostachyus. Likewise, the label appeared earlier in the arbuscular mycorrhiza of C. macrostachyus and in the soil CO(2) efflux as in case of P. falcatus (24 h vs. 72 h). Within one year soil CO(2) efflux amounted to a loss of 32% of assimilated carbon for the gap filling tree and to 15% for the late successional one. Our results showed clear differences in carbon allocation patterns between tree species, although we caution that this experiment was unreplicated. A shift in tree species composition of tropical montane forests (e.g., by degradation) accelerates carbon allocation belowground and increases respiratory carbon losses by the autotrophic community. If ongoing disturbance keeps early successional species in dominance, the larger allocation to fast cycling compartments may deplete soil organic carbon in the long run.

Conservation importance of early post-disturbance temperate forests

Treesearch

Charles Kwit; David I. King; Beverly Collins; Mark E. Swanson

2014-01-01

The early post-disturbance stage of temperate forest succession (also referred to as 'early-seral' or 'early-successional' forest) has been the subject of interest and debate. Often thought of as an ephemeral (and often disorganized) state of eventual closed-canopy systems, its direct and immediate role in conservation traditionally has been ignored...

Responses of Reactive Oxygen Scavenging Enzymes, Proline and Malondialdehyde to Water Deficits among Six Secondary Successional Seral Species in Loess Plateau

PubMed Central

Du, Feng; Shi, Huijun; Zhang, Xingchang; Xu, Xuexuan

2014-01-01

Drought can impact local vegetation dynamics in a long term. In order to predict the possible successional pathway of local community under drought, the responses of some drought resistance indices of six successional seral species in the semi-arid Loss Hilly Region of China were illustrated and compared on three levels of soil water deficits along three growing months (7, 8 and 9). The results showed that: 1) the six species had significant differences in SOD, POD activities and MDA content. The rank correlations between SOD, POD activities and the successional niche positions of the six species were positive, and the correlation between MDA content and the niche positions was negative; 2) activities of SOD, CAT and POD, and content of proline and MDA had significant differences among the three months; 3) there existed significant interactions of SOD, CAT, POD activities and MDA content between months and species. With an exception, no interaction of proline was found. Proline in leaves had a general decline in reproductive month; 4) SOD, CAT, POD activities and proline content had negative correlations with MDA content. Among which, the correlation between SOD activity and MDA content was significant. The results implied that, in arid or semiarid region, the species at later successional stage tend to have strong drought resistance than those at early stage. Anti-drought indices can partially interpret the pathway of community succession in the drought impacted area. SOD activity is more distinct and important on the scope of protecting membrane damage through the scavenging of ROS on exposure to drought. PMID:24914928

Effects of an Early Successional Biological Soil Crust from a Temperate Coastal Sand Dune (NE Germany) on Soil Elemental Stoichiometry and Phosphatase Activity.

PubMed

Schaub, Iris; Baum, Christel; Schumann, Rhena; Karsten, Ulf

2018-06-20

Early successional biological soil crusts (BSCs), a consortium of bacteria, cyanobacteria, and other microalgae, are one of the first settlement stages on temperate coastal sand dunes. In this study, we investigated the algal biomass (Chlorophyll a (Chl a)), algal (C algal ) and microbial carbon (C mic ), elemental stoichiometry (C:N:P), and acid and alkaline phosphatase activity (AcidPA and AlkPA) of two algae-dominated BSCs from a coastal white dune (northeast Germany, on the southwestern Baltic Sea) which differed in the exposure to wind forces. The dune sediment (DS) was generally low in total carbon (TC), nitrogen (TN), and phosphorus (TP). These elements, together with the soil organic matter (SOM) accumulated in the BSC layer and in the sediment underneath (crust sediment CS), leading to initial soil development. The more disturbed BSC (BSC1) exhibited lower algal and microbial biomass and lower C algal /C mic ratios than the undisturbed BSC (BSC2). The BSC1 accumulated more organic carbon (OC) than BSC2. However, the OC in the BSC2 was more effectively incorporated into C mic than in the BSC1, as indicated by lower OC:C mic ratios. The AcidPA (1.1-1.3 μmol g -1  DM h -1 or 147-178 μg g -1  DM h -1 ) and AlkPA (2.7-5.5 μmol g -1  DM h -1 or 372-764 μg g -1  DM h -1 ) were low in both BSCs. The PA, together with the elemental stoichiometry, indicated no P limitation of both BSCs but rather water limitation followed by N limitation for the algae community and a carbon limitation for the microbial community. Our results explain the observed distribution of early successional and more developed BSCs on the sand dune.

A shift from arbuscular mycorrhizal to dark septate endophytic colonization in Deschampsia flexuosa roots occurs along primary successional gradient.

PubMed

Huusko, K; Ruotsalainen, A L; Markkola, A M

2017-02-01

Soil fungal community and dominant mycorrhizal types are known to shift along with plant community changes during primary succession. However, it is not well understood how and why root fungal symbionts and colonization types vary within the plant host when the host species is able to thrive both at young and at old successional stages with different light and nutrient resource availability. We asked (i) how root fungal colonization of Deschampsia flexuosa (Poaceae) by arbuscular mycorrhizal (AM) fungi and dark septate endophytes (DSE) changes along a postglacial primary successional land uplift gradient. As neighboring vegetation may play a role in root fungal colonization, we also asked (ii) whether removal of the dominant neighbor, Empetrum nigrum ssp. hermaphroditum (Ericaceae), affects root fungal colonization of Deschampsia. We also studied whether (iii) foliar carbon (C) and nitrogen (N) concentration of Deschampsia is related to successional changes along a land uplift gradient. AM colonization decreased (-50 %), DSE colonization increased (+200 %), and foliar C declined in Deschampsia along with increasing successional age, whereas foliar N was not affected. Empetrum removal did not affect AM colonization but increased DSE sclerotial colonization especially at older successional stages. The observed decrease in foliar C coincides with an increase in canopy closure along with increasing successional age. We suggest that the shift from an AM-dominated to a DSE-dominated root fungal community in Deschampsia along a land uplift successional gradient may be related to different nutritional benefits gained through these root fungal groups.

Exploiting water versus tolerating drought: water-use strategies of trees in a secondary successional tropical dry forest.

PubMed

Pineda-García, Fernando; Paz, Horacio; Meinzer, Frederick C; Angeles, Guillermo

2016-02-01

In seasonal plant communities where water availability changes dramatically both between and within seasons, understanding the mechanisms that enable plants to exploit water pulses and to survive drought periods is crucial. By measuring rates of physiological processes, we examined the trade-off between water exploitation and drought tolerance among seedlings of trees of a tropical dry forest, and identified biophysical traits most closely associated with plant water-use strategies. We also explored whether early and late secondary successional species occupy different portions of trade-off axes. As predicted, species that maintained carbon capture, hydraulic function and leaf area at higher plant water deficits during drought had low photosynthetic rates, xylem hydraulic conductivity and growth rate under non-limiting water supply. Drought tolerance was associated with more dense leaf, stem and root tissues, whereas rapid resource acquisition was associated with greater stem water storage, larger vessel diameter and larger leaf area per mass invested. We offer evidence that the water exploitation versus drought tolerance trade-off drives species differentiation in the ability of tropical dry forest trees to deal with alternating water-drought pulses. However, we detected no evidence of strong functional differentiation between early and late successional species along the proposed trade-off axes, suggesting that the environmental gradient of water availability across secondary successional habitats in the dry tropics does not filter out physiological strategies of water use among species, at least at the seedling stage. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Remote sensing-based predictors improve distribution models of rare, early successional and broadleaf tree species in Utah

USGS Publications Warehouse

Zimmermann, N.E.; Edwards, T.C.; Moisen, Gretchen G.; Frescino, T.S.; Blackard, J.A.

2007-01-01

1. Compared to bioclimatic variables, remote sensing predictors are rarely used for predictive species modelling. When used, the predictors represent typically habitat classifications or filters rather than gradual spectral, surface or biophysical properties. Consequently, the full potential of remotely sensed predictors for modelling the spatial distribution of species remains unexplored. Here we analysed the partial contributions of remotely sensed and climatic predictor sets to explain and predict the distribution of 19 tree species in Utah. We also tested how these partial contributions were related to characteristics such as successional types or species traits. 2. We developed two spatial predictor sets of remotely sensed and topo-climatic variables to explain the distribution of tree species. We used variation partitioning techniques applied to generalized linear models to explore the combined and partial predictive powers of the two predictor sets. Non-parametric tests were used to explore the relationships between the partial model contributions of both predictor sets and species characteristics. 3. More than 60% of the variation explained by the models represented contributions by one of the two partial predictor sets alone, with topo-climatic variables outperforming the remotely sensed predictors. However, the partial models derived from only remotely sensed predictors still provided high model accuracies, indicating a significant correlation between climate and remote sensing variables. The overall accuracy of the models was high, but small sample sizes had a strong effect on cross-validated accuracies for rare species. 4. Models of early successional and broadleaf species benefited significantly more from adding remotely sensed predictors than did late seral and needleleaf species. The core-satellite species types differed significantly with respect to overall model accuracies. Models of satellite and urban species, both with low prevalence, benefited

Remote sensing-based predictors improve distribution models of rare, early successional and broadleaf tree species in Utah

PubMed Central

ZIMMERMANN, N E; EDWARDS, T C; MOISEN, G G; FRESCINO, T S; BLACKARD, J A

2007-01-01

Compared to bioclimatic variables, remote sensing predictors are rarely used for predictive species modelling. When used, the predictors represent typically habitat classifications or filters rather than gradual spectral, surface or biophysical properties. Consequently, the full potential of remotely sensed predictors for modelling the spatial distribution of species remains unexplored. Here we analysed the partial contributions of remotely sensed and climatic predictor sets to explain and predict the distribution of 19 tree species in Utah. We also tested how these partial contributions were related to characteristics such as successional types or species traits. We developed two spatial predictor sets of remotely sensed and topo-climatic variables to explain the distribution of tree species. We used variation partitioning techniques applied to generalized linear models to explore the combined and partial predictive powers of the two predictor sets. Non-parametric tests were used to explore the relationships between the partial model contributions of both predictor sets and species characteristics. More than 60% of the variation explained by the models represented contributions by one of the two partial predictor sets alone, with topo-climatic variables outperforming the remotely sensed predictors. However, the partial models derived from only remotely sensed predictors still provided high model accuracies, indicating a significant correlation between climate and remote sensing variables. The overall accuracy of the models was high, but small sample sizes had a strong effect on cross-validated accuracies for rare species. Models of early successional and broadleaf species benefited significantly more from adding remotely sensed predictors than did late seral and needleleaf species. The core-satellite species types differed significantly with respect to overall model accuracies. Models of satellite and urban species, both with low prevalence, benefited more from

Trophic level, successional age and trait matching determine specialization of deadwood-based interaction networks of saproxylic beetles

PubMed Central

Gossner, Martin M.; Grass, Ingo; Arnstadt, Tobias; Hofrichter, Martin; Floren, Andreas; Linsenmair, Karl Eduard; Weisser, Wolfgang W.; Steffan-Dewenter, Ingolf

2017-01-01

The specialization of ecological networks provides important insights into possible consequences of biodiversity loss for ecosystem functioning. However, mostly mutualistic and antagonistic interactions of living organisms have been studied, whereas detritivore networks and their successional changes are largely unexplored. We studied the interactions of saproxylic (deadwood-dependent) beetles with their dead host trees. In a large-scale experiment, 764 logs of 13 tree species were exposed to analyse network structure of three trophic groups of saproxylic beetles over 3 successional years. We found remarkably high specialization of deadwood-feeding xylophages and lower specialization of fungivorous and predatory species. During deadwood succession, community composition, network specialization and network robustness changed differently for the functional groups. To reveal potential drivers of network specialization, we linked species' functional traits to their network roles, and tested for trait matching between plant (i.e. chemical compounds) and beetle (i.e. body size) traits. We found that both plant and animal traits are major drivers of species specialization, and that trait matching can be more important in explaining interactions than neutral processes reflecting species abundance distributions. High network specialization in the early successional stage and decreasing network robustness during succession indicate vulnerability of detritivore networks to reduced tree species diversity and beetle extinctions, with unknown consequences for wood decomposition and nutrient cycling. PMID:28469020

Effects of ENSO and Temporal Rainfall Variation on the Dynamics of Successional Communities in Old-Field Succession of a Tropical Dry Forest

PubMed Central

Maza-Villalobos, Susana; Poorter, Lourens; Martínez-Ramos, Miguel

2013-01-01

The effects of temporal variation of rainfall on secondary succession of tropical dry ecosystems are poorly understood. We studied effects of inter-seasonal and inter-year rainfall variation on the dynamics of regenerative successional communities of a tropical dry forest in Mexico. We emphasized the effects caused by the severe El Niño Southern Oscillation (ENSO) occurred in 2005. We established permanent plots in sites representing a chronosequence of Pasture (abandoned pastures, 0–1 years fallow age), Early (3–5), Intermediate (8–12), and Old-Growth Forest categories (n = 3 per category). In total, 8210 shrubs and trees 10 to 100-cm height were identified, measured, and monitored over four years. Rates of plant recruitment, growth and mortality, and gain and loss of species were quantified per season (dry vs. rainy), year, and successional category, considering whole communities and separating seedlings from sprouts and shrubs from trees. Community rates changed with rainfall variation without almost any effect of successional stage. Mortality and species loss rates peaked during the ENSO year and the following year; however, after two rainy years mortality peaked in the rainy season. Such changes could result from the severe drought in the ENSO year, and of the outbreak of biotic agents during the following rainy years. Growth, recruitment and species gain rates were higher in the rainy season but they were significantly reduced after the ENSO year. Seedlings exhibited higher recruitment and mortality rate than sprouts, and shrubs showed higher recruitment than trees. ENSO strongly impacted both the dynamics and trajectory of succession, creating transient fluctuations in the abundance and species richness of the communities. Overall, there was a net decline in plant and species density in most successional stages along the years. Therefore, strong drought events have critical consequences for regeneration dynamics, delaying the successional process

Top predators affect the composition of naive protist communities, but only in their early-successional stage.

PubMed

Zander, Axel; Gravel, Dominique; Bersier, Louis-Félix; Gray, Sarah M

2016-02-01

Introduced top predators have the potential to disrupt community dynamics when prey species are naive to predation. The impact of introduced predators may also vary depending on the stage of community development. Early-succession communities are likely to have small-bodied and fast-growing species, but are not necessarily good at defending against predators. In contrast, late-succession communities are typically composed of larger-bodied species that are more predator resistant relative to small-bodied species. Yet, these aspects are greatly neglected in invasion studies. We therefore tested the effect of top predator presence on early- and late-succession communities that were either naive or non-naive to top predators. We used the aquatic community held within the leaves of Sarracenia purpurea. In North America, communities have experienced the S. purpurea top predator and are therefore non-naive. In Europe, this predator is not present and its niche has not been filled, making these communities top-predator naive. We collected early- and late-succession communities from two non-naive and two naive sites, which are climatically similar. We then conducted a common-garden experiment, with and without the presence of the top predator, in which we recorded changes in community composition, body size spectra, bacterial density, and respiration. We found that the top predator had no statistical effect on global measures of community structure and functioning. However, it significantly altered protist composition, but only in naive, early-succession communities, highlighting that the state of community development is important for understanding the impact of invasion.

Benchmarking successional progress in a quantitative food web.

PubMed

Boit, Alice; Gaedke, Ursula

2014-01-01

Central to ecology and ecosystem management, succession theory aims to mechanistically explain and predict the assembly and development of ecological communities. Yet processes at lower hierarchical levels, e.g. at the species and functional group level, are rarely mechanistically linked to the under-investigated system-level processes which drive changes in ecosystem properties and functioning and are comparable across ecosystems. As a model system for secondary succession, seasonal plankton succession during the growing season is readily observable and largely driven autogenically. We used a long-term dataset from large, deep Lake Constance comprising biomasses, auto- and heterotrophic production, food quality, functional diversity, and mass-balanced food webs of the energy and nutrient flows between functional guilds of plankton and partly fish. Extracting population- and system-level indices from this dataset, we tested current hypotheses about the directionality of successional progress which are rooted in ecosystem theory, the metabolic theory of ecology, quantitative food web theory, thermodynamics, and information theory. Our results indicate that successional progress in Lake Constance is quantifiable, passing through predictable stages. Mean body mass, functional diversity, predator-prey weight ratios, trophic positions, system residence times of carbon and nutrients, and the complexity of the energy flow patterns increased during succession. In contrast, both the mass-specific metabolic activity and the system export decreased, while the succession rate exhibited a bimodal pattern. The weighted connectance introduced here represents a suitable index for assessing the evenness and interconnectedness of energy flows during succession. Diverging from earlier predictions, ascendency and eco-exergy did not increase during succession. Linking aspects of functional diversity to metabolic theory and food web complexity, we reconcile previously disjoint bodies of

Benchmarking Successional Progress in a Quantitative Food Web

PubMed Central

Boit, Alice; Gaedke, Ursula

2014-01-01

Central to ecology and ecosystem management, succession theory aims to mechanistically explain and predict the assembly and development of ecological communities. Yet processes at lower hierarchical levels, e.g. at the species and functional group level, are rarely mechanistically linked to the under-investigated system-level processes which drive changes in ecosystem properties and functioning and are comparable across ecosystems. As a model system for secondary succession, seasonal plankton succession during the growing season is readily observable and largely driven autogenically. We used a long-term dataset from large, deep Lake Constance comprising biomasses, auto- and heterotrophic production, food quality, functional diversity, and mass-balanced food webs of the energy and nutrient flows between functional guilds of plankton and partly fish. Extracting population- and system-level indices from this dataset, we tested current hypotheses about the directionality of successional progress which are rooted in ecosystem theory, the metabolic theory of ecology, quantitative food web theory, thermodynamics, and information theory. Our results indicate that successional progress in Lake Constance is quantifiable, passing through predictable stages. Mean body mass, functional diversity, predator-prey weight ratios, trophic positions, system residence times of carbon and nutrients, and the complexity of the energy flow patterns increased during succession. In contrast, both the mass-specific metabolic activity and the system export decreased, while the succession rate exhibited a bimodal pattern. The weighted connectance introduced here represents a suitable index for assessing the evenness and interconnectedness of energy flows during succession. Diverging from earlier predictions, ascendency and eco-exergy did not increase during succession. Linking aspects of functional diversity to metabolic theory and food web complexity, we reconcile previously disjoint bodies of

Spatial and successional dynamics of microbial biofilm communities in a grassland stream ecosystem

DOE PAGES

Veach, Allison M.; Stegen, James C.; Brown, Shawn P.; ...

2016-09-06

Biofilms represent a metabolically active and structurally complex component of freshwater ecosystems. Ephemeral prairie streams are hydrologically harsh and prone to frequent perturbation. Elucidating both functional and structural community changes over time within prairie streams provides a general understanding of microbial responses to environmental disturbance. In this study, we examined microbial succession of biofilm communities at three sites in a third-order stream at Konza Prairie over a 2- to 64-day period. Microbial abundance (bacterial abundance, chlorophyll a concentrations) increased and never plateaued during the experiment. Net primary productivity (net balance of oxygen consumption and production) of the developing biofilms didmore » not differ statistically from zero until 64 days suggesting a balance of the use of autochthonous and allochthonous energy sources until late succession. Bacterial communities (MiSeq analyses of the V4 region of 16S rRNA) established quickly. Bacterial richness, diversity and evenness were high after 2 days and increased over time. Several dominant bacterial phyla (Beta-, Alphaproteobacteria, Bacteroidetes, Gemmatimonadetes, Acidobacteria, Chloroflexi) and genera ( Luteolibacter, Flavobacterium, Gemmatimonas, Hydrogenophaga) differed in relative abundance over space and time. Bacterial community composition differed across both space and successional time. Pairwise comparisons of phylogenetic turnover in bacterial community composition indicated that early-stage succession (≤16 days) was driven by stochastic processes, whereas later stages were driven by deterministic selection regardless of site. Finally, our data suggest that microbial biofilms predictably develop both functionally and structurally indicating distinct successional trajectories of bacterial communities in this ecosystem.« less

Spatial and successional dynamics of microbial biofilm communities in a grassland stream ecosystem

DOE Office of Scientific and Technical Information (OSTI.GOV)

Veach, Allison M.; Stegen, James C.; Brown, Shawn P.

Biofilms represent a metabolically active and structurally complex component of freshwater ecosystems. Ephemeral prairie streams are hydrologically harsh and prone to frequent perturbation. Elucidating both functional and structural community changes over time within prairie streams provides a general understanding of microbial responses to environmental disturbance. In this study, we examined microbial succession of biofilm communities at three sites in a third-order stream at Konza Prairie over a 2- to 64-day period. Microbial abundance (bacterial abundance, chlorophyll a concentrations) increased and never plateaued during the experiment. Net primary productivity (net balance of oxygen consumption and production) of the developing biofilms didmore » not differ statistically from zero until 64 days suggesting a balance of the use of autochthonous and allochthonous energy sources until late succession. Bacterial communities (MiSeq analyses of the V4 region of 16S rRNA) established quickly. Bacterial richness, diversity and evenness were high after 2 days and increased over time. Several dominant bacterial phyla (Beta-, Alphaproteobacteria, Bacteroidetes, Gemmatimonadetes, Acidobacteria, Chloroflexi) and genera ( Luteolibacter, Flavobacterium, Gemmatimonas, Hydrogenophaga) differed in relative abundance over space and time. Bacterial community composition differed across both space and successional time. Pairwise comparisons of phylogenetic turnover in bacterial community composition indicated that early-stage succession (≤16 days) was driven by stochastic processes, whereas later stages were driven by deterministic selection regardless of site. Finally, our data suggest that microbial biofilms predictably develop both functionally and structurally indicating distinct successional trajectories of bacterial communities in this ecosystem.« less

Successional changes of Collembola and soil microbiota during forest rotation.

PubMed

Chauvat, Matthieu; Zaitsev, Andrei S; Wolters, Volkmar

2003-10-01

Dynamic approaches to forest ecosystems are surprisingly rare. Here we report about successional changes in collembolan community structure and microbial performances during forest rotation. The study was carried out in a chronosequence of four spruce forest stands (5-, 25-, 45-, and 95 years old; Tharandter forest, Germany). CO2 release significantly increased after clear-cutting and the amount of C stored in the organic layer subsequently declined. The early phase of forest rotation was characterized by a very active decomposer microflora, stimulation of both fungi and bacteria as well as by a high abundance of surface-oriented Collembola. In addition, collembolan species turnover was accelerated. While the biomass of fungi further increased at intermediate stages of forest rotation, the metabolic activity of the microflora was low, the functional diversity of bacteria declined and the collembolan community became impoverished. Euedaphic species dominated during this stage of forest development. These changes can be explained by both reduction in microhabitat diversity and depletion of food sources associated with an accumulation of recalcitrant soil organic matter. Results of the General Regression Model procedure indicate a shift from specific associations between collembolan functional groups and microbiota at the early stage of forest rotation to a more diffuse pattern at intermediate stages. Though the hypothesis that Collembola are relatively responsive to changes in environmental conditions is confirmed, consistently high community similarity suggests a remarkable persistence of some components of microarthropod assemblages. Our study provides evidence for substantial ecosystem-level implications of changes in the soil food web during forest rotation. Moreover, correlations between bacterial parameters and Collembola point to the overarching impact of differences in the composition of the microbial community on microarthropods.

Floristic and vegetation successional processes within landslides in a Mediterranean environment.

PubMed

Neto, Carlos; Cardigos, Patrícia; Oliveira, Sérgio Cruz; Zêzere, José Luís

2017-01-01

Floristic and vegetation analysis in seven Mediterranean landslides led to the understanding of the successional processes occurring in different landslide disturbed sectors. Our study showed that in landslides that occurred between 1996 and 2010 there is a clear differentiation between the three main landslide sectors (scarp, main body and foot) concerning floristic composition, vegetation structure, floristic richness, successional processes and plant functional type. Additional differences were found between landslide areas and undisturbed agricultural areas adjacent to landslides. In this study 48 floristic relevés were made using a stratified random sampling design. The main landslide body exhibits the highest floristic richness whereas the landslide scarp has the lowest coverage rate and the highest presence of characteristic species from ruderal and strongly perturbed habitats. Finally, the landslide foot shows a late stage in the succession (maquis or pre-forest stage) with a high dominance of vines. We further discuss the importance of landslides as reservoirs of biodiversity especially for Mediterranean orchids. Copyright © 2016 Elsevier B.V. All rights reserved.

Large Blooms of Bacillales (Firmicutes) Underlie the Response to Wetting of Cyanobacterial Biocrusts at Various Stages of Maturity.

PubMed

Karaoz, Ulas; Couradeau, Estelle; da Rocha, Ulisses Nunes; Lim, Hsiao-Chien; Northen, Trent; Garcia-Pichel, Ferran; Brodie, Eoin L

2018-03-06

and global significance. Ecosystem succession toward maturity has been associated with both resistance and resilience to disturbance. Recent work has shown that the impacts of both climate change and physical disturbance on biocrusts increase the potential for successional resetting. A larger proportion of biocrusts are expected to be at an early developmental stage, hence increasing susceptibility to changes in precipitation frequencies. Therefore, it is essential to characterize how biocrusts respond to wetting across early developmental stages. In this study, we document the wetting response of microbial communities from a biocrust chronosequence. Overall, our results suggest that the cumulative effects of altered precipitation frequencies on the stability of biocrusts will depend on biocrust maturity. Copyright © 2018 Karaoz et al.

Nutrient fluxes in litterfall of a secondary successional alluvial rain forest in Southern Brazil.

PubMed

Scheer, Maurício Bergamini; Gatti, Gustavo; Wisniewski, Celina

2011-12-01

During forest succession, litterfall nutrient fluxes increase significantly. The higher inputs of organic matter and nutrients through litterfall affects positively soil fertility and the species composition, which are essential components in forest restoration and management programs. In the present study, the input of nutrients to the forest soil via litterfall components was estimated for two sites of different development stages, in an early successional alluvial rain forest in Brazil. Litterfall returned to the soil, in kg/ha, ca. 93 N, 79 Ca, 24 K, 15 Mg, 6 P, 1.7 Mn, 0.94 Fe, 0.18 Zn, 0.09 Cu and 11.2 Al, in the site where trees were more abundant and had higher values of basal area. In the other area, where trees where less abundant and values of basal area were comparatively low, litterfall returned < 50% of those amounts to the forest soil, except for Al. The amount of Al that returned to the soil was similar in both areas due to the high contribution of Tibouchina pulchra (82% of Al returned). Comparatively, high proportion of three dominant native tree species (Myrsine coriacea, T. pulchra and Cecropia pachystachya) explained better litter nutrient use efficiency (mainly N and P) in the site with the least advanced successional stage. Although litterfall of these species show lower nutrient concentrations than the other tree species, their nutrient fluxes were high in both sites, indicating a certain independence from soil essential nutrients. Such feature of the native species is very advantageous and should be considered in forest restoration programs.

The effect of local and landscape-level characteristics on the abundance of forest birds in early-successional habitats during the post-fledging season in western Massachusetts

Treesearch

Michelle A. Labbe; David I. King; Tim A. Mousseau

2014-01-01

Many species of mature forest-nesting birds ("forest birds") undergo a pronounced shift in habitat use during the post-fledging period and move from their forest nesting sites into areas of early-successional vegetation. Mortality is high during this period, thus understanding the resource requirements of post-fledging birds has implications for conservation...

Successional Distance between the Source and Recipient Influence Seed Germination and Seedling Survival during Surface Soil Replacement in SW China

PubMed Central

Shen, You-xin; Gao, Lei; Xia, Xue; Li, Yuhui; Guan, Huilin

2013-01-01

Adding propagules (source) to a degraded site (recipient) is a common way of manipulating secondary succession to restore diversity and services formerly provided by forests. However, heretofore no study has considered the effect of “successional distance” between source and recipient site. Four sites in the Shilin karst area of SW China were treated as different states along a secondary successional sere: grass, shrub, young secondary forest, and primary forest. Ten 1 m ×1m soil quadrats in the grass, shrub and young forest sites were replaced with 10 cm deep soil sources from corresponding later successional stage(s) in January 2009. Woody plant seed germination was monitored in the first year and seedling survival was monitored until the end of the second year. At the end of 2010, 2097 seeds of woody plants belonging to 45 taxa had germinated, and 3.9% of the seedlings and 7.8% of the species survived. Germination of most species was sensitive to ambient light (red, far-red, R:FR ratios, photosynthetically active radiation). Soil source and recipient site had a significant effect on the total number of seeds and number of species that germinated, and on the percentage of seedlings that survived through the end of the second year. Closer successional stages between recipient site and soil source had higher seed germination and seedling-survival percentages. However, a transition threshold exists in the young forest state, where seeds can germinate but not survive the second year. Our results, although based on an unreplicated chronosequence, suggest that successional distance between soil sources and recipient sites affect forest recruitment and restoration in degraded karst of SW China. PMID:24223891

Microbial community composition but not diversity changes along succession in arctic sand dunes.

PubMed

Poosakkannu, Anbu; Nissinen, Riitta; Männistö, Minna; Kytöviita, Minna-Maarit

2017-02-01

The generality of increasing diversity of fungi and bacteria across arctic sand dune succession was tested. Microbial communities were examined by high-throughput sequencing of 16S rRNA genes (bacteria) and internal transcribed spacer (ITS) regions (fungi). We studied four microbial compartments (inside leaf, inside root, rhizosphere and bulk soil) and characterized microbes associated with a single plant species (Deschampsia flexuosa) across two sand dune successional stages (early and late). Bacterial richness increased across succession in bulk soil and leaf endosphere. In contrast, soil fungal richness remained constant while root endosphere fungal richness increased across succession. There was, however, no significant difference in Shannon diversity indices between early and late successional stage in any compartment. There was a significant difference in the composition of microbial communities between early and late successional stage in all compartments, although the major microbial OTUs were shared between early and late successional stage. Co-occurrence network analysis revealed successional stage-specific microbial groups. There were more co-occurring modules in early successional stage than in late stage. Altogether, these results emphasize that succession strongly affects distribution of microbial species, but not microbial diversity in arctic sand dune ecosystem and that fungi and bacteria may not follow the same successional trajectories. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

Shift in community structure in an early-successional Mediterranean shrubland driven by long-term experimental warming and drought and natural extreme droughts.

PubMed

Liu, Daijun; Estiarte, Marc; Ogaya, Romà; Yang, Xiaohong; Peñuelas, Josep

2017-10-01

Global warming and recurring drought are expected to accelerate water limitation for plant communities in semiarid Mediterranean ecosystems and produce directional shifts in structure and composition that are not easily detected, and supporting evidence is scarce. We conducted a long-term (17 years) nocturnal-warming (+0.6°C) and drought (-40% rainfall) experiments in an early-successional Mediterranean shrubland to study the changes in community structure and composition, contrasting functional groups and dominant species, and the superimposed effects of natural extreme drought. Species richness decreased in both the warming and drought treatments. Responses to the moderate warming were associated with decreases in herb abundance, and responses to the drought were associated with decreases in both herb and shrub abundances. The drought also significantly decreased community diversity and evenness. Changes in abundance differed between herbs (decreases) and shrubs (increases or no changes). Both warming and drought, especially drought, increased the relative species richness and abundance of shrubs, favoring the establishment of shrubs. Both warming and drought produced significant shifts in plant community composition. Experimental warming shifted the community composition from Erica multiflora toward Rosmarinus officinalis, and drought consistently shifted the composition toward Globularia alypum. The responses in biodiversity (e.g., community biodiversity, changes of functional groups and compositional shifts) were also strongly correlated with atmospheric drought (SPEI) in winter-spring and/or summer, indicating sensitivity to water limitation in this early-successional Mediterranean ecosystem, especially to natural extreme droughts. Our results suggest that the shifts in species assembles and community diversity and composition are accelerated by the long-term nocturnal-warming and drought, combined with natural severe droughts, and that the magnitude of the

Rain forest fragmentation and the proliferation of successional trees.

PubMed

Laurance, William F; Nascimento, Henrique E M; Laurance, Susan G; Andrade, Ana C; Fearnside, Philip M; Ribeiro, José E L; Capretz, Robson L

2006-02-01

The effects of habitat fragmentation on diverse tropical tree communities are poorly understood. Over a 20-year period we monitored the density of 52 tree species in nine predominantly successional genera (Annona, Bellucia, Cecropia, Croton, Goupia, Jacaranda, Miconia, Pourouma, Vismia) in fragmented and continuous Amazonian forests. We also evaluated the relative importance of soil, topographic, forest dynamic, and landscape variables in explaining the abundance and species composition of successional trees. Data were collected within 66 permanent 1-ha plots within a large (approximately 1000 km2) experimental landscape, with forest fragments ranging from 1 to 100 ha in area. Prior to forest fragmentation, successional trees were uncommon, typically comprising 2-3% of all trees (> or =10 cm diameter at breast height [1.3 m above the ground surface]) in each plot. Following fragmentation, the density and basal area of successional trees increased rapidly. By 13-17 years after fragmentation, successional trees had tripled in abundance in fragment and edge plots and constituted more than a quarter of all trees in some plots. Fragment age had strong, positive effects on the density and basal area of successional trees, with no indication of a plateau in these variables, suggesting that successional species could become even more abundant in fragments over time. Nonetheless, the 52 species differed greatly in their responses to fragmentation and forest edges. Some disturbance-favoring pioneers (e.g., Cecropia sciadophylla, Vismia guianensis, V. amazonica, V. bemerguii, Miconia cf. crassinervia) increased by >1000% in density on edge plots, whereas over a third (19 of 52) of all species remained constant or declined in numbers. Species responses to fragmentation were effectively predicted by their median growth rate in nearby intact forest, suggesting that faster-growing species have a strong advantage in forest fragments. An ordination analysis revealed three main

Seedlings of subtropical rainforest species from similar successional guild show different photosynthetic and morphological responses to varying light levels.

PubMed

Lestari, D Puji; Nichols, J Doland

2017-02-01

Restoration using rainforest species in Australia and elsewhere has been limited to a small number of widely known species, mainly pioneer or early successional species, Using the presumed successional status as a guideline for species selection in reforestation should be taken with a caveat since a species' capacity to adjust to light gradients is not easily predicted. This study examined the photosynthetic and growth responses of four Australian subtropical rainforest species in the context of using late successional species in restoration programs. Since the selected species [Sloanea australis ((Benth.) F. Muell.), Cinnamomum oliveri (F. M. Bailey),Caldcluvia paniculosa ((F. Muell.) Hoogland) and Geissois benthamiana (F. Muell.)] are considered late-successional species, this study also discussed the possibility of separating these species according to their acclimation level towards light gradients. Seedlings of four species were grown under four light treatments using neutral density shade cloth (5, 33, 64 and 80% irradiance) during summer November 2014 to February 2015. All species demonstrated a narrow range of photosynthetic acclimation to different light levels, experienced photoinhibition and photodamage in 80% irradiance and allocated more biomass to leaves in 5% irradiance, supporting their classification as late successional species. Cinnamomum oliveri was the only species able to utilize higher irradiance, with a higher light saturated rate of photosynthesis than the other species. Canonical analysis of principal coordinates revealed that the degree of plasticity of each species in response to contrasting irradiance levels varied. This analysis separated the species into three light tolerance classes: obligate shade-adapted species (S. australis and G. benthamiana), high light-adapted species (C. paniculosa) and the generalist (C. oliveri). Overall, this study suggests that the four species can be planted and will grow well under 33-64% irradiance

Successional forest dynamics 30 years following clearcutting

Treesearch

Lindsay R. Boring; Katherine J. Elliott; Wayne T. Swank

2014-01-01

For the past several decades, clearcuts on experimental watersheds have provided an opportunity to examine how these large-scale forest disturbances influence various ecosystem processes, including stream hydrology, soil eriosion, nutrient cycling, and vegetation diversity and successional patterns. For the investigation of vegetation diversity and successional...

Climatic sensitivity of dryland soil CO2 fluxes differs dramatically with biological soil crust successional state

USGS Publications Warehouse

Tucker, Colin; Ferrenberg, Scott; Reed, Sasha C.

2018-01-01

Arid and semiarid ecosystems make up approximately 41% of Earth’s terrestrial surface and are suggested to regulate the trend and interannual variability of the global terrestrial carbon (C) sink. Biological soil crusts (biocrusts) are common dryland soil surface communities of bryophytes, lichens, and/or cyanobacteria that bind the soil surface together and that may play an important role in regulating the climatic sensitivity of the dryland C cycle. Major uncertainties exist in our understanding of the interacting effects of changing temperature and moisture on CO2 uptake (photosynthesis) and loss (respiration) from biocrust and sub-crust soil, particularly as related to biocrust successional state. Here, we used a mesocosm approach to assess how biocrust successional states related to climate treatments. We subjected bare soil (Bare), early successional lightly pigmented cyanobacterial biocrust (Early), and late successional darkly pigmented moss-lichen biocrust (Late) to either ambient or + 5°C above ambient soil temperature for 84 days. Under ambient temperatures, Late biocrust mesocosms showed frequent net uptake of CO2, whereas Bare soil, Early biocrust, and warmed Late biocrust mesocosms mostly lost CO2 to the atmosphere. The inhibiting effect of warming on CO2 exchange was a result of accelerated drying of biocrust and soil. We used these data to parameterize, via Bayesian methods, a model of ecosystem CO2 fluxes, and evaluated the model with data from an autochamber CO2 system at our field site on the Colorado Plateau in SE Utah. In the context of the field experiment, the data underscore the negative effect of warming on fluxes both biocrust CO2 uptake and loss—which, because biocrusts are a dominant land cover type in this ecosystem, may extend to ecosystem-scale C cycling.

Successional changes in trophic interactions support a mechanistic model of post-fire population dynamics.

PubMed

Smith, Annabel L

2018-01-01

Models based on functional traits have limited power in predicting how animal populations respond to disturbance because they do not capture the range of demographic and biological factors that drive population dynamics, including variation in trophic interactions. I tested the hypothesis that successional changes in vegetation structure, which affected invertebrate abundance, would influence growth rates and body condition in the early-successional, insectivorous gecko Nephrurus stellatus. I captured geckos at 17 woodland sites spanning a succession gradient from 2 to 48 years post-fire. Body condition and growth rates were analysed as a function of the best-fitting fire-related predictor (invertebrate abundance or time since fire) with different combinations of the co-variates age, sex and location. Body condition in the whole population was positively affected by increasing invertebrate abundance and, in the adult population, this effect was most pronounced for females. There was strong support for a decline in growth rates in weight with time since fire. The results suggest that increased early-successional invertebrate abundance has filtered through to a higher trophic level with physiological benefits for insectivorous geckos. I integrated the new findings about trophic interactions into a general conceptual model of mechanisms underlying post-fire population dynamics based on a long-term research programme. The model highlights how greater food availability during early succession could drive rapid population growth by contributing to previously reported enhanced reproduction and dispersal. This study provides a framework to understand links between ecological and physiological traits underlying post-fire population dynamics.

Dynamics, chemical properties and bioavailability of DOC in an early successional catchment

NASA Astrophysics Data System (ADS)

Risse-Buhl, U.; Hagedorn, F.; Dümig, A.; Gessner, M. O.; Schaaf, W.; Nii-Annang, S.; Gerull, L.; Mutz, M.

2013-07-01

The dynamics of dissolved organic carbon (DOC) have been intensively studied in mature ecosystems, but little is known about DOC dynamics and the significance of DOC as a substrate for microbial activity in early-successional catchments. We determined the concentration, chemical composition, source, radiocarbon age, and bioavailability of DOC along the hydrological flow path from soil solution to a downstream pond in a recently constructed catchment (Chicken Creek Catchment, Germany). Soil solution, upwelling ground water, stream water, subsurface water in an alluvial fan, and pond water all had high DOC concentrations (averages: 6.0-11.6 mg DOC L-1), despite small carbon stocks in both vegetation and soil of the catchment. Solid-state CPMAS 13C NMR of DOC in upwelling ground water revealed a higher proportion of aromatic compounds (32%) and a lower proportion of carbohydrates (33%) than in pond water (18% and 45%, respectively). The average 14C age of DOC in upwelling ground water was 2600 to 2900 yr, while organic matter of the Quaternary substrate of the catchment had a 14C age of 3000 to 16 000 yr. Both the 14C age data and 13C NMR spectra suggest that DOC partly derived from organic matter of the Quaternary substrate (about 40 to 90% of the C in the DOC), indicating that both recent and old C of the DOC can support microbial activity during early ecosystem succession. However, in a 70 day incubation experiment, only about 11% of the total DOC was found to be bioavailable. This proportion was irrespective of the water type. Origin of the microbial communities within the catchment (enriched from soil, stream sediment or pond water) also had only a marginal effect on overall DOC utilization.

Nitrogen alters carbon dynamics during early succession in boreal forest

Treesearch

Steven D. Allison; Tracy B. Gartner; Michelle C. Mack; Krista McGuire; Kathleen Treseder

2010-01-01

Boreal forests are an important source of wood products, and fertilizers could be used to improve forest yields, especially in nutrient poor regions of the boreal zone. With climate change, fire frequencies may increase, resulting in a larger fraction of the boreal landscape present in early successional stages. Since most fertilization studies have focused on mature...

Characterization of successional changes in bacterial community composition during bioremediation of used motor oil-contaminated soil in a boreal climate.

PubMed

Yan, Lijuan; Sinkko, Hanna; Penttinen, Petri; Lindström, Kristina

2016-01-15

The widespread use of motor oil makes it a notable risk factor to cause scattered contamination in soil. The monitoring of microbial community dynamics can serve as a comprehensive tool to assess the ecological impact of contaminants and their disappearance in the ecosystem. Hence, a field study was conducted to monitor the ecological impact of used motor oil under different perennial cropping systems (fodder galega, brome grass, galega-brome grass mixture and bare fallow) in a boreal climate zone. Length heterogeneity PCR characterized a successional pattern in bacterial community following oil contamination over a four-year bioremediation period. Soil pH and electrical conductivity were associated with the shifts in bacterial community composition. Crops had no detectable effect on bacterial community composition or complexity. However, the legume fodder galega increased soil microbial biomass, expressed as soil total DNA. Oil contamination induced an abrupt change in bacterial community composition at the early stage, yet the effect did not last as long as the oil in soil. The successional variation in bacterial community composition can serve as a sensitive ecological indicator of oil contamination and remediation in situ. Copyright © 2015 Elsevier B.V. All rights reserved.

Scrub-successional bird community dynamics in young and mature longleaf pine-wiregrass savannahs

USGS Publications Warehouse

Krementz, D.G.; Christie, J.S.

1999-01-01

Public agencies are required to manage for threatened and endangered species and for biodiversity. However, at times, management for threatened and endangered species precludes consideration of other species. We investigated how managing for red-cockaded woodpeckers (Picoides borealis) and biodiversity at the Savannah River Site (SRS), South Carolina, affected communities of bird species that use early-successional scrub habitat (hereafter, scrub-successional species). Management for red-cockaded woodpeckers at the SRS involved both (1) manipulating mature longleaf pine (Pinus palustris)-wiregrass (Andropogon spp.) stands via canopy thinning, removal of midstory trees, and prescribed burning; and (2) even-aged timber harvesting. The former management practice encouraged red-cockaded woodpeckers to establish new colonies in previously unoccupied stands (hereafter, 'recruitment' stands). The latter management practice is used to remove off-site planted pines and replant with preferred longleaf pines. We conducted a constant-effort mist net study in recruitment and regenerating stands (stands clearcut and planted with longleaf pine) during the breeding seasons of 1995-96. We hypothesized that the scrub-successional bird community in recruitment stands would have greater species richness and higher survival and reproductive rates per species than in regenerating stands. However, recruitment stands always had fewer scrub-successional species (1995:36 species; 1996:31 species) than regenerating stands (1995:54 species; 1996:55 species), and all species that occurred in recruitment stands also occurred in regenerating stands. Species which commonly occurred in both recruitment and regenerating stands had similar adult:juvenile ratios (P > 0.15) and relative proportion of adults in breeding condition (P > 0.05). We detected no difference in survival rates of Bachman's sparrows (Aimophila aestivalis), indigo buntings (Passerina cyanea), and of 'combined' scrub-successional

Lepidoptera outbreaks in response to successional changes after the passage of Hurricane Hugo in Puerto Rico Rico

Treesearch

J.A. Torres

1992-01-01

Fifteen species of Lepidoptera occurred in large numbers in spring and early summer after the passage of Hurricane Hugo over the north-east of Puerto Rico. Spodoptera eridania (Noctuidae) was the most common of the larvae and fed on 56 plant species belonging to 31 families. All the Lepidoptera fed on early successional vegetation. Some of the plants represent new host...

Seasonal dynamics of the plant community and soil seed bank along a successional gradient in a subalpine meadow on the Tibetan Plateau.

PubMed

Ma, Miaojun; Zhou, Xianhui; Qi, Wei; Liu, Kun; Jia, Peng; Du, Guozhen

2013-01-01

Knowledge about how change the importance of soil seed bank and relationship between seed mass and abundance during vegetation succession is crucial for understanding vegetation dynamics. Many studies have been conducted, but their ecological mechanisms of community assembly are not fully understood. We examined the seasonal dynamics of the vegetation and soil seed bank as well as seed size distribution along a successional gradient. We also explored the potential role of the soil seed bank in plant community regeneration, the relationship between seed mass and species abundance, and the relative importance of deterministic and stochastic processes along a successional gradient. Species richness of seed bank increased (shallow layer and the total) and seed density decreased (each layer and the total) significantly with succession. Species richness and seed density differed significantly between different seasons and among soil depths. Seed mass showed a significant negative relationship with relative abundance in the earliest successional stage, but the relationships were not significant in later stages. Seed mass showed no relationship with relative abundance in the whole successional series in seed bank. Results were similar for both July 2005 and April 2006. The seed mass and abundance relationship was determined by a complex interaction between small and larger seeded species and environmental factors. Both stochastic processes and deterministic processes were important determinants of the structure of the earliest stage. The importance of seed bank decreased with succession. The restoration of abandoned farmed and grazed meadows to the species-rich subalpine meadow in Tibetan Plateau can be successfully achieved from the soil seed bank. However, at least 20 years are required to fully restore an abandoned agricultural meadow to a natural mature subalpine meadow.

Effects of water level, shade and time on germination and growth of freshwater marsh plants along a simulated successional gradient

USGS Publications Warehouse

Kellogg, C.H.; Bridgham, S.D.; Leicht, S.A.

2003-01-01

1. We examined the effect of soil organic content (1.4, 3.6, 7.2% soil C), water level (+2, -1, -4 cm from soil surface) and duration (13 or 33 days) on 10 species that varied in abundance during succession in freshwater marshes. We also determined the effect of shade (0, 40, 80% shade) and soil organic content (1.4 and 7.2% soil C) on germination of six species over 62 days with water 0.5 cm below the soil surface. 2. Water level consistently affected species germination on both dates. Above-ground biomass was generally higher with increasing organic content of soil, but shade had little effect on germination or height. 3 The hydrologic zone in which species were found in the field was a good indicator of the response of germination to hydrology. Both early successional species and species wide-spread across the successional gradient show similar germination on all organic contents, while later successional species appear to germinate best at higher organic contents. 4. Successional changes in soils are capable of affecting plant community development, independent of disturbance.

Response of Tridens flavus (L.) A. S. Hitchc. to soil nutrients and disturbance in an early successional old field

USGS Publications Warehouse

Honu, Y.A.K.; Gibson, D.J.; Middleton, B.A.

2006-01-01

Soil nutrients and disturbance are two of the main abiotic factors that influence plant dominance (canopy cover), density, and fecundity in early successional old field plant communities. The manner in which the dominant species in old field successional systems respond to the interaction of nutrients and disturbance is poorly known. We examined the dominance, density of flowering tillers, and reproductive output of Tridens flavus, a perennial, warm-season bunchgrass that is important in old field succession, to varying soil nutrient and disturbance regimes. We tested the hypothesis that the interaction between nutrients and disturbance would influence the performance (cover, density, fecundity) of T. flavus. To test this hypothesis, we subjected 25 m2 experimental plots to various combinations of fertilizer and mowing treatments for eight years after initially plowing the field. The performance of T. flavus was measured by estimating percent cover for 8 years (1996-2003) and both density of flowering tillers and reproductive output (panicle length and number of branches per panicle) for three years (2001-2003). The pattern of canopy cover of T. flavus over the first eight years of succession varied over time depending on mowing regime. Dominance was significantly higher in plots that were fertilized only in years one and five than in annually fertilized and unfertilized control plots. The length of panicles and density of flowering tillers were both significantly greater in annually mowed plots than in unmowed plots. In the absence of mowing in particular, T. flavus became overtopped by woody species and declined in this old field community. Therefore, disturbances such as mowing and fertilization may be important in maintaining grasses such as Tridens flavus in old fields.

Supplemental planting of early successional tree species during bottomland hardwood afforestation

USGS Publications Warehouse

Twedt, D.J.; Wilson, R.R.; Outcalt, Kenneth W.

2002-01-01

Reforestation of former bottom land hardwood forests that have been cleared for agriculture (i.e., afforestation) has historically emphasized planting heavy-seeded oaks (Quercus spp.) and pecans (Carya spp.). These species are slow to develop vertical forest structure. However, vertical forest structure is key to colonization of afforested sites by forest birds. Although early-successional tree species often enhance vertical structure, few of these species invade afforested sites that are distant from seed sources. Furthermore, many land mangers are reluctant to establish and maintain stands of fast-growing plantation trees. Therefore, on 40 afforested bottomland sites, we supplemented heavy-seeded seedlings with 8 patches of fast-growing trees: 4 patches of 12 eastern cottonwood (Populus deltoides) stem cuttings and 4 patches of 12 American sycamore (Platanus occidentalis) seedlings. To enhance survival and growth, tree patches were subjected to 4 weed control treatments: (1) physical weed barriers, (2) chemical herbicide, (3) both physical and chemical weed control, or (4) no weed control. Overall, first-year survival of cottonwood and sycamore was 25 percent and 47 percent, respectively. Second-year survival of extant trees was 52 percent for cottonwood and 77 percent for sycamore. Physical weed barriers increased survival of cottonwoods to 30 percent versus 18 percent survival with no weed control. Similarly, sycamore survival was increased from 49 percent without weed control to 64 percent with physical weed barriers. Chemical weed control adversely impacted sycamore and reduced survival to 35 percent. Tree heights did not differ between species or among weed control treatments. Girdling of trees by deer often destroyed saplings. Thus, little increase in vertical structure was detected between growing seasons. Application of fertilizer and protection via tree shelters did not improve survival or vertical development of sycamore or cottonwood.

Comparison of throughfall chemistry in a mature hemlock forest and an early-successional deciduous forest resulting from salvage logging in Whately, Massachusetts

NASA Astrophysics Data System (ADS)

Zukswert, J. M.; Rhodes, A. L.; Dwyer, C. H.; Sweezy, T.

2012-12-01

Removal of foundation species as a result of disturbance events such as exotic species invasions can alter community composition and ecosystem function. The current hemlock woolly adelgid (Adelges tsugae) infestation in eastern North America that threatens the eastern hemlock (Tsuga canadensis), a foundation species, has motivated salvage logging efforts. Ecological succession resulting from salvage logging of hemlock would eventually produce a deciduous hardwood forest. The chemistry of throughfall beneath a mature hemlock forest canopy is expected to be more acidic than throughfall from a mature deciduous forest canopy because hemlock foliage releases more organic acids and fewer base cations. The chemical composition of throughfall during the early successional transition from hemlock to deciduous is less understood. We hypothesize that throughfall chemistry in a deciduous forest consisting primarily of juvenile trees may be more similar to direct precipitation because leaf area index is smaller. Differences between hemlock throughfall and direct precipitation may be larger due to the denser canopy of these mature trees. We compared the chemical composition of precipitation, hemlock throughfall, and black birch throughfall for 26 precipitation events from 4 March to 30 July 2012. The black birch (Betula lenta) forest patch resulted from salvage logging of hemlocks twenty years ago at the MacLeish Field Station in Whately, MA. From the three plots we measured the volume of water collected and pH, acid neutralizing capacity, dissolved organic carbon (DOC), and concentrations of cations (Ca2+, K+, Na+, Mg2+, NH4+), anions (Cl-, NO3-, SO42-), and dissolved silica. Precipitation totaled 405 mm during the course of the study. Throughfall totaled 347 mm in the black birch plot and 315 mm in the hemlock plot. The proportion of precipitation passing through the forest canopy was smaller in hemlock throughfall than black birch throughfall during small precipitation events

Accelerating development of late-successional features in second-growth pine stands of the Goosenest Adaptive Management Area

Treesearch

Martin W. Ritchie; Kathleen A. Harcksen

2005-01-01

This paper describes implementation and early results of a large-scale, interdisciplinary experiment in the Goosenest Adaptive Management Area in northeastern California. The study is designed to investigate development of late-successional forest attributes in second-growth ponderosa pine stands. The experiment has four treatments replicated five times and encompasses...

Repeated burning of eastern tallgrass prairie increases richness and diversity, stabilizing late successional vegetation.

PubMed

Bowles, Marlin L; Jones, Michael D

2013-03-01

Understanding temporal effects of fire frequency on plant species diversity and vegetation structure is critical for managing tallgrass prairie (TGP), which occupies a mid-continental longitudinal precipitation and productivity gradient. Eastern TGP has contributed little information toward understanding whether vegetation-fire interactions are uniform or change across this biome. We resampled 34 fire-managed mid- and late-successional ungrazed TGP remnants occurring across a dry to wet-mesic moisture gradient in the Chicago region of Illinois, USA. We compared hypotheses that burning acts either as a stabilizing force or causes change in diversity and structure, depending upon fire frequency and successional stage. Based on western TGP, we expected a unimodal species richness distribution across a cover-productivity gradient, variable functional group responses to fire frequency, and a negative relationship between fire frequency and species richness. Species diversity was unimodal across the cover gradient and was more strongly humpbacked in stands with greater fire frequency. In support of a stabilizing hypothesis, temporal similarity of late-successional vegetation had a logarithmic relationship with increasing fire frequency, while richness and evenness remained stable. Temporal similarity within mid-successional stands was not correlated with fire frequency, while richness increased and evenness decreased over time. Functional group responses to fire frequency were variable. Summer forb richness increased under high fire frequency, while C4 grasses, spring forbs, and nitrogen-fixing species decreased with fire exclusion. On mesic and wet-mesic sites, vegetation structure measured by the ratio of woody to graminoid species was negatively correlated with abundance of forbs and with fire frequency. Our findings that species richness responds unimodally to an environmental-productivity gradient, and that fire exclusion increases woody vegetation and leads to loss

Dispersal limitation drives successional pathways in Central Siberian forests under current and intensified fire regimes.

PubMed

Tautenhahn, Susanne; Lichstein, Jeremy W; Jung, Martin; Kattge, Jens; Bohlman, Stephanie A; Heilmeier, Hermann; Prokushkin, Anatoly; Kahl, Anja; Wirth, Christian

2016-06-01

Fire is a primary driver of boreal forest dynamics. Intensifying fire regimes due to climate change may cause a shift in boreal forest composition toward reduced dominance of conifers and greater abundance of deciduous hardwoods, with potential biogeochemical and biophysical feedbacks to regional and global climate. This shift has already been observed in some North American boreal forests and has been attributed to changes in site conditions. However, it is unknown if the mechanisms controlling fire-induced changes in deciduous hardwood cover are similar among different boreal forests, which differ in the ecological traits of the dominant tree species. To better understand the consequences of intensifying fire regimes in boreal forests, we studied postfire regeneration in five burns in the Central Siberian dark taiga, a vast but poorly studied boreal region. We combined field measurements, dendrochronological analysis, and seed-source maps derived from high-resolution satellite images to quantify the importance of site conditions (e.g., organic layer depth) vs. seed availability in shaping postfire regeneration. We show that dispersal limitation of evergreen conifers was the main factor determining postfire regeneration composition and density. Site conditions had significant but weaker effects. We used information on postfire regeneration to develop a classification scheme for successional pathways, representing the dominance of deciduous hardwoods vs. evergreen conifers at different successional stages. We estimated the spatial distribution of different successional pathways under alternative fire regime scenarios. Under intensified fire regimes, dispersal limitation of evergreen conifers is predicted to become more severe, primarily due to reduced abundance of surviving seed sources within burned areas. Increased dispersal limitation of evergreen conifers, in turn, is predicted to increase the prevalence of successional pathways dominated by deciduous hardwoods

Interactions with successional stage and nutrient status determines the life-form-specific effects of increased soil temperature on boreal forest floor vegetation.

PubMed

Hedwall, Per-Ola; Skoglund, Jerry; Linder, Sune

2015-02-01

The boreal forest is one of the largest terrestrial biomes and plays a key role for the global carbon balance and climate. The forest floor vegetation has a strong influence on the carbon and nitrogen cycles of the forests and is sensitive to changes in temperature conditions and nutrient availability. Additionally, the effects of climate warming on forest floor vegetation have been suggested to be moderated by the tree layer. Data on the effects of soil warming on forest floor vegetation from the boreal forest are, however, very scarce. We studied the effects on the forest floor vegetation in a long-term (18 years) soil warming and fertilization experiment in a Norway spruce stand in northern Sweden. During the first 9 years, warming favored early successional species such as grasses and forbs at the expense of dwarf shrubs and bryophytes in unfertilized stands, while the effects were smaller after fertilization. Hence, warming led to significant changes in species composition and an increase in species richness in the open canopy nutrient limited forest. After another 9 years of warming and increasing tree canopy closure, most of the initial effects had ceased, indicating an interaction between forest succession and warming. The only remaining effect of warming was on the abundance of bryophytes, which contrary to the initial phase was strongly favored by warming. We propose that the suggested moderating effects of the tree layer are specific to plant life-form and conclude that the successional phase of the forest may have a considerable impact on the effects of climate change on forest floor vegetation and its feedback effects on the carbon and nitrogen cycles, and thus on the climate.

Interactions with successional stage and nutrient status determines the life-form-specific effects of increased soil temperature on boreal forest floor vegetation

PubMed Central

Hedwall, Per-Ola; Skoglund, Jerry; Linder, Sune

2015-01-01

The boreal forest is one of the largest terrestrial biomes and plays a key role for the global carbon balance and climate. The forest floor vegetation has a strong influence on the carbon and nitrogen cycles of the forests and is sensitive to changes in temperature conditions and nutrient availability. Additionally, the effects of climate warming on forest floor vegetation have been suggested to be moderated by the tree layer. Data on the effects of soil warming on forest floor vegetation from the boreal forest are, however, very scarce. We studied the effects on the forest floor vegetation in a long-term (18 years) soil warming and fertilization experiment in a Norway spruce stand in northern Sweden. During the first 9 years, warming favored early successional species such as grasses and forbs at the expense of dwarf shrubs and bryophytes in unfertilized stands, while the effects were smaller after fertilization. Hence, warming led to significant changes in species composition and an increase in species richness in the open canopy nutrient limited forest. After another 9 years of warming and increasing tree canopy closure, most of the initial effects had ceased, indicating an interaction between forest succession and warming. The only remaining effect of warming was on the abundance of bryophytes, which contrary to the initial phase was strongly favored by warming. We propose that the suggested moderating effects of the tree layer are specific to plant life-form and conclude that the successional phase of the forest may have a considerable impact on the effects of climate change on forest floor vegetation and its feedback effects on the carbon and nitrogen cycles, and thus on the climate. PMID:25750720

Multitrait successional forest dynamics enable diverse competitive coexistence

PubMed Central

Brännström, Åke; Westoby, Mark; Dieckmann, Ulf

2017-01-01

To explain diversity in forests, niche theory must show how multiple plant species coexist while competing for the same resources. Although successional processes are widespread in forests, theoretical work has suggested that differentiation in successional strategy allows only a few species stably to coexist, including only a single shade tolerant. However, this conclusion is based on current niche models, which encode a very simplified view of plant communities, suggesting that the potential for niche differentiation has remained unexplored. Here, we show how extending successional niche models to include features common to all vegetation—height-structured competition for light under a prevailing disturbance regime and two trait-mediated tradeoffs in plant function—enhances the diversity of species that can be maintained, including a diversity of shade tolerants. We identify two distinct axes of potential niche differentiation, corresponding to the traits leaf mass per unit leaf area and height at maturation. The first axis allows for coexistence of different shade tolerances and the second axis for coexistence among species with the same shade tolerance. Addition of this second axis leads to communities with a high diversity of shade tolerants. Niche differentiation along the second axis also generates regions of trait space wherein fitness is almost equalized, an outcome we term “evolutionarily emergent near-neutrality.” For different environmental conditions, our model predicts diverse vegetation types and trait mixtures, akin to observations. These results indicate that the outcomes of successional niche differentiation are richer than previously thought and potentially account for mixtures of traits and species observed in forests worldwide. PMID:28283658

A comparison of seed banks across a sand dune successional gradient at Lake Michigan dunes (Indiana, USA)

USGS Publications Warehouse

Leicht-Young, S. A.; Pavlovic, N.B.; Grundel, R.; Frohnapple, K.J.

2009-01-01

In habitats where disturbance is frequent, seed banks are important for the regeneration of vegetation. Sand dune systems are dynamic habitats in which sand movement provides intermittent disturbance. As succession proceeds from bare sand to forest, the disturbance decreases. At Indiana Dunes National Lakeshore, we examined the seed banks of three habitat types across a successional gradient: foredunes, secondary dunes, and oak savanna. There were differences among the types of species that germinated from each of the habitats. The mean seed bank density increased across the successional gradient by habitat, from 376 to 433 to 968 seeds m-2, but with foredune and secondary dune seed bank densities being significantly lower than the savanna seed bank density. The number of seeds germinated was significantly correlated with soil organic carbon, demonstrating for this primary successional sequence that seed density increases with stage and age. The seed bank had much lower species richness than that of the aboveground vegetation across all habitats. Among sites within a habitat type, the similarity of species germinated from the seed banks was very low, illustrating the variability of the seed bank even in similar habitat types. These results suggest that restoration of these habitats cannot rely on seed banks alone. ?? 2008 Springer Science+Business Media B.V.

Effects of antemortem ingestion of ethanol on insect successional patterns and development of Phormia regina (Diptera: Calliphoridae).

PubMed

Tabor, Kimberly L; Fell, Richard D; Brewster, Carlyle C; Pelzer, Kevin; Behonick, George S

2005-05-01

The effects of antemortem ingestion of ethanol by domestic pigs, Sus scrofa L., on postmortem insect successional patterns and the development of Phormia regina (Meigen) were studied during summer 2003 in Blacksburg, VA. Insect samples were collected from the carcasses of ethanol-treated and untreated pigs for 10 d postmortem during two successional studies. In total, 32 insect taxa were collected during the two studies, with 29 and 27 taxa observed on the carcasses of ethanol-treated and untreated pigs, respectively. The earliest arrivers to both carcass types were dipterans. This group was represented by six families, with P. regina and Phaenicia coeruleiviridis (Macquart) being the most common calliphorids. Beetles in six families were collected on the carcasses of ethanol-treated pigs, but only three of the families were collected on carcasses of the untreated pigs. Permutation analyses to test the null hypothesis of no similarity between successional patterns of insect taxa from carcasses of ethanol-treated and untreated pigs showed that the successional patterns were similar between carcass types in the first (P = 0.003) and the second (P = 0.01) studies. The results of the development study of P. regina maggots in the field show that there was a significant difference between the distributions of length for maggots reared on loin tissue from ethanol-treated and untreated pigs. Maggots that fed on tissue from ethanol-treated pigs took approximately 11.9 h longer to reach the pupal stage than maggots that fed on tissue from untreated pigs. The longer developmental time for maggots on tissue from ethanol-treated pigs was due mainly to the longer postfeeding period of the third instar.

Litterfall production along successional and altitudinal gradients of subtropical monsoon evergreen broadleaved forests in Guangdong, China

USGS Publications Warehouse

Zhou, G.; Guan, L.; Wei, X.; Zhang, Dongxiao; Zhang, Q.; Yan, J.; Wen, D.; Liu, J.; Liu, S.; Huang, Z.; Kong, G.; Mo, J.; Yu, Q.

2007-01-01

Evaluation of litterfall production is important for understanding nutrient cycling, forest growth, successional pathways, and interactions with environmental variables in forest ecosystems. Litterfall was intensively studied during the period of 1982-2001 in two subtropical monsoon vegetation gradients in the Dinghushan Biosphere Reserve, Guangdong Province, China. The two gradients include: (1) a successional gradient composed of pine forest (PF), mixed pine and broadleaved forest (MF) and monsoon evergreen broadleaved forest (BF), and (2) an altitudinal gradient composed of Baiyunci ravine rain forest (BRF), Qingyunci ravine rain forest (QRF), BF and mountainous evergreen broadleaved forest (MMF). Mean annual litterfall production was 356, 861 and 849 g m-2 for PF, MF and BF of the successional gradient, and 1016, 1061, 849 and 489 g m-2 for BRF, QRF, BF and MMF of the altitudinal gradient, respectively. As expected, mean annual litterfall of the pioneer forest PF was the lowest, but rapidly increased over the observation period while those in other forests were relatively stable, confirming that forest litterfall production is closely related to successional stages and growth patterns. Leaf proportions of total litterfall in PF, MF, BF, BRF, QRF and MMF were 76.4%, 68.4%, 56.8%, 55.7%, 57.6% and 69.2%, respectively, which were consistent with the results from studies in other evergreen broadleaved forests. Our analysis on litterfall monthly distributions indicated that litterfall production was much higher during the period of April to September compared to other months for all studied forest types. Although there were significant impacts of some climate variables (maximum and effective temperatures) on litterfall production in some of the studied forests, the mechanisms of how climate factors (temperature and rainfall) interactively affect litterfall await further study. ?? 2006 Springer Science+Business Media B.V.

Comparative performances of staging systems for early hepatocellular carcinoma.

PubMed

Nathan, Hari; Mentha, Gilles; Marques, Hugo P; Capussotti, Lorenzo; Majno, Pietro; Aldrighetti, Luca; Pulitano, Carlo; Rubbia-Brandt, Laura; Russolillo, Nadia; Philosophe, Benjamin; Barroso, Eduardo; Ferrero, Alessandro; Schulick, Richard D; Choti, Michael A; Pawlik, Timothy M

2009-08-01

Several staging systems for patients with hepatocellular carcinoma (HCC) have been proposed, but studies of their prognostic accuracy have yielded conflicting conclusions. Stratifying patients with early HCC is of particular interest because these patients may derive the greatest benefit from intervention, yet no studies have evaluated the comparative performances of staging systems in patients with early HCC. A retrospective cohort study was performed using data on 379 patients who underwent liver resection or liver transplantation for HCC at six major hepatobiliary centres in the USA and Europe. The staging systems evaluated were: the Okuda staging system, the International Hepato-Pancreato-Biliary Association (IHPBA) staging system, the Cancer of the Liver Italian Programme (CLIP) score, the Barcelona Clinic Liver Cancer (BCLC) staging system, the Japanese Integrated Staging (JIS) score and the American Joint Committee on Cancer/International Union Against Cancer (AJCC/UICC) staging system, 6th edition. A recently proposed early HCC prognostic score was also evaluated. The discriminative abilities of the staging systems were evaluated using Cox proportional hazards models and the bootstrap-corrected concordance index (c). Overall survival of the cohort was 74% at 3 years and 52% at 5 years, with a median survival of 62 months. Most systems demonstrated poor discriminatory ability (P > 0.05 on Cox proportional hazards analysis, c approximately 0.5). However, the AJCC/UICC system clearly stratified patients (P < 0.001, c = 0.59), albeit only into two groups. The early HCC prognostic score also clearly stratified patients (P < 0.001, c = 0.60) and identified three distinct prognostic groups. The early HCC prognostic score is superior to the AJCC/UICC staging system (6th edition) for predicting the survival of patients with early HCC after liver resection or liver transplantation. Other major HCC staging systems perform poorly in patients with early HCC.

Plant functional traits suggest a change in novel ecological strategies for dominant species in the stages of forest succession.

PubMed

Chai, Yongfu; Yue, Ming; Wang, Mao; Xu, Jinshi; Liu, Xiao; Zhang, Ruichang; Wan, Pengcheng

2016-03-01

In forest succession, the ecological strategies of the dominant species that are based on functional traits are important in the determination of both the mechanisms and the potential directions of succession. Thirty-one plots were established in the Loess Plateau region of northern Shaanxi in China. Fifteen leaf traits were measured for the 31 dominant species that represented the six stages of succession, and the traits included four that were related to morphology, seven to stoichiometry and four to physiological ecology. The species from the different successional stages had different patterns of distribution of the traits, and different key traits predicted the turnover of the species during succession. The ash and the cellulose contents were key regulatory factors of species turnover in the early successional communities, and the trait niche forces in sugar and leaf dry mass content might become more important with the progression of succession. When only the three herb stages were considered, a progressive replacement of the ruderal by the competitive-ruderal species occurred in the intermediate stages of succession, which was followed by the stress-tolerant-competitive or the competitive-stress tolerant-ruderal strategists late in the succession. Thus, the different species that occurred in the different stages of succession shared different trait-based ecological strategies. Additionally, these differences occurred concomitantly with a shift toward competitive-stress tolerant-ruderal strategies.

Rapid Shifts in Soil Nutrients and Decomposition Enzyme Activity in Early Succession Following Forest Fire

DOE PAGES

Knelman, Joseph E.; Graham, Emily B.; Ferrenberg, Scott; ...

2017-09-15

In post-disturbance landscapes nutrient availability has proven a major control on ecological succession. In this study, we examined variation in connections between soil nutrient availability and decomposition extracellular enzyme activity (EEA) across post fire secondary succession in forest soils as well as after a secondary flood disturbance. We also examined possible linkages between edaphic properties and bacterial communities based on 16S rRNA gene analysis. We found that with advancing succession in a post-fire landscape, the relationship between soil nutrients and EEA became stronger over time. In general, late successional soils showed stronger connections between EEA and soil nutrient status, whilemore » early successional soils were marked by a complete decoupling of nutrients and EEA. We also found that soil moisture and bacterial communities of post-fire disturbance soils were susceptible to change following the secondary flood disturbance, while undisturbed, reference forest soils were not. Our results demonstrate that nutrient pools correlating with EEA change over time. While past work has largely focused on ecosystem succession on decadal timescales, our work suggests that nutrients shift in their relative importance as a control of decomposition EEA in the earliest stages of secondary succession. Furthermore, this work emphasizes the relevance of successional stage, even on short timescales, in predicting rates of carbon and nitrogen cycling, especially as disturbances become more frequent in a rapidly changing world.« less

Rapid Shifts in Soil Nutrients and Decomposition Enzyme Activity in Early Succession Following Forest Fire

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knelman, Joseph E.; Graham, Emily B.; Ferrenberg, Scott

In post-disturbance landscapes nutrient availability has proven a major control on ecological succession. In this study, we examined variation in connections between soil nutrient availability and decomposition extracellular enzyme activity (EEA) across post fire secondary succession in forest soils as well as after a secondary flood disturbance. We also examined possible linkages between edaphic properties and bacterial communities based on 16S rRNA gene analysis. We found that with advancing succession in a post-fire landscape, the relationship between soil nutrients and EEA became stronger over time. In general, late successional soils showed stronger connections between EEA and soil nutrient status, whilemore » early successional soils were marked by a complete decoupling of nutrients and EEA. We also found that soil moisture and bacterial communities of post-fire disturbance soils were susceptible to change following the secondary flood disturbance, while undisturbed, reference forest soils were not. Our results demonstrate that nutrient pools correlating with EEA change over time. While past work has largely focused on ecosystem succession on decadal timescales, our work suggests that nutrients shift in their relative importance as a control of decomposition EEA in the earliest stages of secondary succession. Furthermore, this work emphasizes the relevance of successional stage, even on short timescales, in predicting rates of carbon and nitrogen cycling, especially as disturbances become more frequent in a rapidly changing world.« less

OLD-FIELD SUCCESSIONAL DYNAMICS FOLLOWING INTENSIVE HERBIVORY

EPA Science Inventory

Community composition and successional patterns can be altered by disturbance and exotic species invasions. Our objective was to describe vegetation dynamics following cessation of severe disturbance, which was heavy grazing by cattle, in an old-field grassland subject to invasi...

Successional dynamics in Neotropical forests are as uncertain as they are predictable

PubMed Central

Norden, Natalia; Angarita, Héctor A.; Bongers, Frans; Martínez-Ramos, Miguel; Granzow-de la Cerda, Iñigo; van Breugel, Michiel; Lebrija-Trejos, Edwin; Meave, Jorge A.; Vandermeer, John; Williamson, G. Bruce; Finegan, Bryan; Mesquita, Rita; Chazdon, Robin L.

2015-01-01

Although forest succession has traditionally been approached as a deterministic process, successional trajectories of vegetation change vary widely, even among nearby stands with similar environmental conditions and disturbance histories. Here, we provide the first attempt, to our knowledge, to quantify predictability and uncertainty during succession based on the most extensive long-term datasets ever assembled for Neotropical forests. We develop a novel approach that integrates deterministic and stochastic components into different candidate models describing the dynamical interactions among three widely used and interrelated forest attributes—stem density, basal area, and species density. Within each of the seven study sites, successional trajectories were highly idiosyncratic, even when controlling for prior land use, environment, and initial conditions in these attributes. Plot factors were far more important than stand age in explaining successional trajectories. For each site, the best-fit model was able to capture the complete set of time series in certain attributes only when both the deterministic and stochastic components were set to similar magnitudes. Surprisingly, predictability of stem density, basal area, and species density did not show consistent trends across attributes, study sites, or land use history, and was independent of plot size and time series length. The model developed here represents the best approach, to date, for characterizing autogenic successional dynamics and demonstrates the low predictability of successional trajectories. These high levels of uncertainty suggest that the impacts of allogenic factors on rates of change during tropical forest succession are far more pervasive than previously thought, challenging the way ecologists view and investigate forest regeneration. PMID:26080411

Successional dynamics in Neotropical forests are as uncertain as they are predictable.

PubMed

Norden, Natalia; Angarita, Héctor A; Bongers, Frans; Martínez-Ramos, Miguel; Granzow-de la Cerda, Iñigo; van Breugel, Michiel; Lebrija-Trejos, Edwin; Meave, Jorge A; Vandermeer, John; Williamson, G Bruce; Finegan, Bryan; Mesquita, Rita; Chazdon, Robin L

2015-06-30

Although forest succession has traditionally been approached as a deterministic process, successional trajectories of vegetation change vary widely, even among nearby stands with similar environmental conditions and disturbance histories. Here, we provide the first attempt, to our knowledge, to quantify predictability and uncertainty during succession based on the most extensive long-term datasets ever assembled for Neotropical forests. We develop a novel approach that integrates deterministic and stochastic components into different candidate models describing the dynamical interactions among three widely used and interrelated forest attributes--stem density, basal area, and species density. Within each of the seven study sites, successional trajectories were highly idiosyncratic, even when controlling for prior land use, environment, and initial conditions in these attributes. Plot factors were far more important than stand age in explaining successional trajectories. For each site, the best-fit model was able to capture the complete set of time series in certain attributes only when both the deterministic and stochastic components were set to similar magnitudes. Surprisingly, predictability of stem density, basal area, and species density did not show consistent trends across attributes, study sites, or land use history, and was independent of plot size and time series length. The model developed here represents the best approach, to date, for characterizing autogenic successional dynamics and demonstrates the low predictability of successional trajectories. These high levels of uncertainty suggest that the impacts of allogenic factors on rates of change during tropical forest succession are far more pervasive than previously thought, challenging the way ecologists view and investigate forest regeneration.

Successional trends in Sonoran Desert abandoned agricultural fields in northern Mexico

USGS Publications Warehouse

Castellanos, A.E.; Martinez, M.J.; Llano, J.M.; Halvorson, W.L.; Espiricueta, M.; Espejel, I.

2005-01-01

Excessive ground-water use and saline intrusion to the aquifer led, in less than three decades, to an increase in abandoned agricultural fields at La Costa de Hermosillo, within the Sonoran Desert. Using a chronosequence from years since abandonment, patterns of field succession were developed. Contrary to most desert literature, species replacement was found, both in fields with and without saline intrusion. Seasonal photosynthetic capacity as well as water and nitrogen use efficiencies were different in dominant early and late successional plant species. These ecological findings provided a framework for a general explanation of species dominance and replacement within abandoned agricultural fields in the Sonoran Desert. ?? 2004 Elsevier Ltd. All rights reserved.

76 FR 81430 - Small Business Investment Companies-Early Stage SBICs; Public Webinars

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-28

... SMALL BUSINESS ADMINISTRATION 13 CFR Part 107 Small Business Investment Companies--Early Stage... Webinars regarding its proposed Early Stage Small Business Investment Companies (Early Stage SBIC) rule. The proposed Early Stage SBIC rule defines a new sub-category of small business investment companies...

Morphogenesis of early stage melanoma

NASA Astrophysics Data System (ADS)

Chatelain, Clément; Amar, Martine Ben

2015-08-01

Melanoma early detection is possible by simple skin examination and can insure a high survival probability when successful. However it requires efficient methods for identifying malignant lesions from common moles. This paper provides an overview first of the biological and physical mechanisms controlling melanoma early evolution, and then of the clinical tools available today for detecting melanoma in vivo at an early stage. It highlights the lack of diagnosis methods rationally linking macroscopic observables to the microscopic properties of the tissue, which define the malignancy of the tumor. The possible inputs of multiscale models for improving these methods are shortly discussed.

Early stages of soldering reactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lord, R.A.; Umantsev, A.

2005-09-15

An experiment on the early stages of intermetallic compound layer growth during soldering and its theoretical analysis were conducted with the intent to study the controlling factors of the process. An experimental technique based on fast dipping and pulling of a copper coupon in liquid solder followed by optical microscopy allowed the authors to study the temporal behavior of the sample on a single micrograph. The technique should be of value for different areas of metallurgy because many experiments on crystallization may be described as the growth of a layer of intermediate phase. Comparison of the experimental results with themore » theoretical calculations allowed one to identify the kinetics of dissolution as the rate-controlling mechanism on the early stages and measure the kinetic coefficient of dissolution. A popular model of intermetallic compound layer structure coarsening is discussed.« less

EGFR mutations in early-stage and advanced-stage lung adenocarcinoma: Analysis based on large-scale data from China.

PubMed

Pi, Can; Xu, Chong-Rui; Zhang, Ming-Feng; Peng, Xiao-Xiao; Wei, Xue-Wu; Gao, Xing; Yan, Hong-Hong; Zhou, Qing

2018-05-02

EGFR-tyrosine kinase inhibitors play an important role in the treatment of advanced non-small cell lung cancer (NSCLC). EGFR mutations in advanced NSCLC occur in approximately 35% of Asian patients and 60% of patients with adenocarcinoma. However, the frequency and type of EGFR mutations in early-stage lung adenocarcinoma remain unclear. We retrospectively collected data on patients diagnosed with lung adenocarcinoma tested for EGFR mutation. Early stage was defined as pathological stage IA-IIIA after radical lung cancer surgery, and advanced stage was defined as clinical stage IIIB without the opportunity for curative treatment or stage IV according to the American Joint Committee on Cancer Staging Manual, 7th edition. A total of 1699 patients were enrolled in this study from May 2014 to May 2016; 750 were assigned to the early-stage and 949 to the advanced-stage group. Baseline characteristics of the two groups were balanced, except that there were more smokers in the advanced-stage group (P < 0.001). The total EGFR mutation rate in the early-stage group was similar to that in the advanced-stage group (53.6% vs. 51.4%, respectively; P = 0.379). There was no significant difference in EGFR mutation type between the two groups. In subgroup analysis of smoking history, there was no difference in EGFR mutation frequency or type between the early-stage and advanced-stage groups. Early-stage and advanced-stage groups exhibited the same EGFR mutation frequencies and types. © 2018 The Authors. Thoracic Cancer published by China Lung Oncology Group and John Wiley & Sons Australia, Ltd.

A reply to King et al

Treesearch

Mark E. Swanson; Jerry F. Franklin; Robert L. Beschta; Charles M. Crisafulli; Dominick A. DellaSala; Richard Hutto; David Lindenmayer; Frederick J. Swanson

2011-01-01

King et al are correct in their assessment of an increase in research and management interest in early successional stages after disturbance. But their claim that “... the conservation status of species that depend on early successional forest is now widely appreciated by natural resource management agencies” merits further reflection. Etc.

Population genetic structure of an edaphic beetle (Ptiliidae) among late successional reserves within the Klamath-Siskiyou ecoregion, California

Treesearch

Ryan M. Caesar; Nancy Gillette; Anthony I. Cognato

2005-01-01

The Klamath-Siskiyou ecoregion of northern California is one of the most diverse temperate coniferous forests. A network of "late successional reserves" (LSRs) has been established to maintain characteristics of late successional forest and to promote late successional characteristics in younger stands. Also, an important goal of conservation management is...

Chemical defense of early life stages of benthic marine invertebrates.

PubMed

Lindquist, Niels

2002-10-01

Accurate knowledge of factors affecting the survival of early life stages of marine invertebrates is critically important for understanding their population dynamics and the evolution of their diverse reproductive and life-history characteristics. Chemical defense is an important determinant of survival for adult stages of many sessile benthic invertebrates, yet relatively little consideration has been given to chemical defenses at the early life stages. This review examines the taxonomic breadth of early life-stage chemical defense in relation to various life-history and reproductive characteristics, as well as possible constraints on the expression of chemical defense at certain life stages. Data on the localization of defensive secondary metabolites in larvae and the fitness-related consequences of consuming even a small amount of toxic secondary metabolites underpin proposals regarding the potential for Müllerian and Batesian mimicry to occur among marine larvae. The involvement of microbial symbionts in the chemical defense of early life stages illustrates its complexity for some species. As our knowledge of chemical defenses in early life stages grows, we will be able to more rigorously examine connections among phylogeny, chemical defenses, and the evolution of reproductive and life-history characteristics among marine invertebrates.

Influence of gap-scale disturbance on developmental and successional pathways in Quercus-Pinus stands

Treesearch

T.A. Weber; J.L. Hart; C. Schweitzer; D.C. Dey

2014-01-01

Quercus-Pinus forests of the eastern USA cover millions of hectares and span a variety of ecoregions. Understanding the influence of natural disturbance on developmental and successional pathways is important for managers that wish to sustain Pinus spp. in these mixtures. Quantifying developmental and successional patterns in this...

Surgical treatment for apparent early stage endometrial cancer

PubMed Central

2014-01-01

Most experts would agree that the standard surgical treatment for endometrial cancer includes a hysterectomy and bilateral salpingo-oophorectomy; however, the benefit of full surgical staging with lymph node dissection in patients with apparent early stage disease remains a topic of debate. Recent prospective data and advances in laparoscopic techniques have transformed this disease into one that can be successfully managed with minimally invasive surgery. This review will discuss the current surgical management of apparent early stage endometrial cancer and some of the new techniques that are being incorporated. PMID:24596812

A PROBABILITY SURVEY OF SUCCESSIONAL FOREST COMPOSITION AND CONDITION IN A GREAT RIVER FLOODPLAIN LANDSCAPE

EPA Science Inventory

Floodplains within the Great River Ecosystems (GREs) of the central U.S. are composed of dynamic mosaics of successional habitat that (when unmodified) are typically dominated by cottonwood forest (Populus ssp.). GRE riparian habitat condition and successional dynamics are linked...

Using rangeland health assessment to inform successional management

USDA-ARS?s Scientific Manuscript database

Rangeland health assessment provides qualitative information on ecosystem attributes. Successional management is a conceptual framework that allows managers to link information gathered in rangeland health assessment to ecological processes that need to be repaired to allow vegetation to change in ...

Late-successional forests and northern spotted owls: how effective is the Northwest Forest Plan?

Treesearch

Miles Hemstrom; Martin G. Raphael

2000-01-01

This paper describes the late-successional and old-growth forest and the northern spotted owl effectiveness monitoring plans for the Northwest Forest Plan. The effectiveness monitoring plan for late-successional and old-growth forests will track changes in forest spatial distribution, and within-stand structure and composition, and it will predict future trends.

Spiritual Diversity and Living with Early-Stage Dementia.

PubMed

McGee, Jocelyn Shealy; Zhao, Holly Carlson; Myers, Dennis R; Seela Eaton, Hannah

2018-01-01

Attention to spiritual diversity is necessary for the provision of culturally informed clinical care for people with early-stage dementia and their family members. In this article, an evidence-based theoretical framework for conceptualizing spiritual diversity is described in detail (Pargament, 2011). The framework is then applied to two clinical case studies of people living with early-stage dementia to elucidate the multilayered components of spiritual diversity in this population. The case studies were selected from a larger mixed-methods study on spirituality, positive psychological factors, health, and well-being in people living with early-stage dementia and their family members. To our knowledge this is the first systematic attempt to apply a theoretical framework for understanding spiritual diversity in this population. Implications for clinical practice are provided.

Moss harvest truncates the successional development of epiphytic bryophytes in the Pacific Northwest.

PubMed

Peck, Jerilynn E; Frelich, Lee E

2008-01-01

We evaluated the impact of commercial moss harvest on the development of an understory epiphyte community in the Pacific Northwest by characterizing natural development stages using data from both a long-term regrowth study and demographic sampling. First, experimentally stripped 1 m long cylindrats on 46 shrub stems in the Oregon Coast Range were monitored for species composition and abundance annually during the first five years of recovery and again in year 10. Second, a pathway of community development was inferred by examining the relative species composition and abundance of epiphytic species present in moss mats in a four-stage chronosequence. We (1) characterized the change in richness and composition from year 1 through 10 of regrowth following experimental disturbance, (2) quantified the proportion of approximately 1-, 10-, 25-, and 50-year-old moss mats of commercially harvestable species that were monodominant, diverse, and late successional, and (3) contrasted these proportions with estimates from a compositional transition matrix derived from long-term monitoring. Roughly half of the observed moss mats demonstrated neutral dynamics and were composed of a mixture of readily dispersed acrocarps and pleurocarps. The remaining half exhibited positive dynamics and were dominated by aggressively growing pleurocarpous species such as Isothecium myosuroides. Following structural developmental pathways well established for vascular plants, moss mats shift with time from high diversity and evenness in the initial colonization and extended establishment phases to increasing Isothecium dominance during a presumed competitive-exclusion phase. Old mats exist in alternate states of either Isothecium dominance or mixed composition, either of which may have late-successional species. Patchy historic commercial moss harvest likely facilitated high diversity by increasing the simultaneous occurrence of all moss mat age classes, while modern strip harvesting methods are

Classification of community types, successional sequences, and landscapes of the Copper River Delta, Alaska.

Treesearch

Keith. Boggs

2000-01-01

A classification of community types, successional sequences, and landscapes is presented for the piedmont of the Copper River Delta. The classification was based on a sampling of 471 sites. A total of 75 community types, 42 successional sequences, and 6 landscapes are described. The classification of community types reflects the existing vegetation communities on the...

76 FR 76907 - Small Business Investment Companies-Early Stage SBICs

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-09

... respect to geographic location. SBA's primary concern in terms of geography is to ensure that the Early... SBICs is the primary source of cash used to service their SBA debt. SBA expects that some Early Stage...--Early Stage SBICs AGENCY: U.S. Small Business Administration. ACTION: Proposed rule. SUMMARY: In this...

Phylogenetic constraints do not explain the rarity of nitrogen-fixing trees in late-successional temperate forests.

PubMed

Menge, Duncan N L; DeNoyer, Jeanne L; Lichstein, Jeremy W

2010-08-06

Symbiotic nitrogen (N)-fixing trees are rare in late-successional temperate forests, even though these forests are often N limited. Two hypotheses could explain this paradox. The 'phylogenetic constraints hypothesis' states that no late-successional tree taxa in temperate forests belong to clades that are predisposed to N fixation. Conversely, the 'selective constraints hypothesis' states that such taxa are present, but N-fixing symbioses would lower their fitness. Here we test the phylogenetic constraints hypothesis. Using U.S. forest inventory data, we derived successional indices related to shade tolerance and stand age for N-fixing trees, non-fixing trees in the 'potentially N-fixing clade' (smallest angiosperm clade that includes all N fixers), and non-fixing trees outside this clade. We then used phylogenetically independent contrasts (PICs) to test for associations between these successional indices and N fixation. Four results stand out from our analysis of U.S. trees. First, N fixers are less shade-tolerant than non-fixers both inside and outside of the potentially N-fixing clade. Second, N fixers tend to occur in younger stands in a given geographical region than non-fixers both inside and outside of the potentially N-fixing clade. Third, the potentially N-fixing clade contains numerous late-successional non-fixers. Fourth, although the N fixation trait is evolutionarily conserved, the successional traits are relatively labile. These results suggest that selective constraints, not phylogenetic constraints, explain the rarity of late-successional N-fixing trees in temperate forests. Because N-fixing trees could overcome N limitation to net primary production if they were abundant, this study helps to understand the maintenance of N limitation in temperate forests, and therefore the capacity of this biome to sequester carbon.

Phylogenetic Constraints Do Not Explain the Rarity of Nitrogen-Fixing Trees in Late-Successional Temperate Forests

PubMed Central

Menge, Duncan N. L.; DeNoyer, Jeanne L.; Lichstein, Jeremy W.

2010-01-01

Background Symbiotic nitrogen (N)-fixing trees are rare in late-successional temperate forests, even though these forests are often N limited. Two hypotheses could explain this paradox. The ‘phylogenetic constraints hypothesis’ states that no late-successional tree taxa in temperate forests belong to clades that are predisposed to N fixation. Conversely, the ‘selective constraints hypothesis’ states that such taxa are present, but N-fixing symbioses would lower their fitness. Here we test the phylogenetic constraints hypothesis. Methodology/Principal Findings Using U.S. forest inventory data, we derived successional indices related to shade tolerance and stand age for N-fixing trees, non-fixing trees in the ‘potentially N-fixing clade’ (smallest angiosperm clade that includes all N fixers), and non-fixing trees outside this clade. We then used phylogenetically independent contrasts (PICs) to test for associations between these successional indices and N fixation. Four results stand out from our analysis of U.S. trees. First, N fixers are less shade-tolerant than non-fixers both inside and outside of the potentially N-fixing clade. Second, N fixers tend to occur in younger stands in a given geographical region than non-fixers both inside and outside of the potentially N-fixing clade. Third, the potentially N-fixing clade contains numerous late-successional non-fixers. Fourth, although the N fixation trait is evolutionarily conserved, the successional traits are relatively labile. Conclusions/Significance These results suggest that selective constraints, not phylogenetic constraints, explain the rarity of late-successional N-fixing trees in temperate forests. Because N-fixing trees could overcome N limitation to net primary production if they were abundant, this study helps to understand the maintenance of N limitation in temperate forests, and therefore the capacity of this biome to sequester carbon. PMID:20700466

Late-successional and old-growth forest effectiveness monitoring plan for the Northwest Forest Plan.

Treesearch

Miles Hemstrom; Thomas Spies; Craig Palmer; Ross Kiester; John Teply; Phil McDonald; Ralph. Warbington

1998-01-01

This report presents options for long-term effectiveness monitoring of late-successional and old-growth forests under the Northwest Forest Plan. It describes methods to answer questions about how much late-successional forest exists on Federal land, its pattern, how it’s changing, and if the Forest Plan is providing for its conservation and management. It specifies...

Living with early-stage dementia: a review of qualitative studies.

PubMed

Steeman, Els; de Casterlé, Bernadette Dierckx; Godderis, Jan; Grypdonck, Mieke

2006-06-01

This paper presents a literature review whose aim was to provide better understanding of living with early-stage dementia. Even in the early stages, dementia may challenge quality of life. Research on early-stage dementia is mainly in the domain of biomedical aetiology and pathology, providing little understanding of what it means to live with dementia. Knowledge of the lived experience of having dementia is important in order to focus pro-active care towards enhancing quality of life. Qualitative research is fundamentally well suited to obtaining an insider's view of living with early-stage dementia. We performed a meta-synthesis of qualitative research findings. We searched MEDLINE, CINAHL, and PsycINFO and reviewed the papers cited in the references of pertinent articles, the references cited in a recently published book on the subjective experience of dementia, one thesis, and the journal Dementia. Thirty-three pertinent articles were identified, representing 28 separate studies and 21 different research samples. Findings were coded, grouped, compared and integrated. Living with dementia is described from the stage a person discovers the memory impairment, through the stage of being diagnosed with dementia, to that of the person's attempts to integrate the impairment into everyday life. Memory loss often threatens perceptions of security, autonomy and being a meaningful member of society. At early stages of memory loss, individuals use self-protecting and self-adjusting strategies to deal with perceived changes and threats. However, the memory impairment itself may make it difficult for an individual to deal with these changes, thereby causing frustration, uncertainty and fear. Our analysis supports the integration of proactive care into the diagnostic process, because even early-stage dementia may challenge quality of life. Moreover, this care should actively involve both the individual with dementia and their family so that both parties can adjust positively

Photons from the early stages of relativistic heavy-ion collisions

NASA Astrophysics Data System (ADS)

Oliva, L.; Ruggieri, M.; Plumari, S.; Scardina, F.; Peng, G. X.; Greco, V.

2017-07-01

We present results about photon-production in relativistic heavy-ion collisions. The main novelty of our study is the calculation of the contribution of the early-stage photons to the photon spectrum. The initial stage is modeled by an ensemble of classical gluon fields which decay to a quark-gluon plasma via the Schwinger mechanism, and the evolution of the system is studied by coupling classical field equations to relativistic kinetic theory; photon production is then computed by including the pertinent collision processes into the collision integral. We find that the contribution of the early-stage photons to the direct photon spectrum is substantial for pT≈2 GeV and higher, the exact value depending on the collision energy; therefore, we identify this part of the photon spectrum as the sign of the early stage. Moreover, the amount of photons produced during the early stage is not negligible with respect to those produced by a thermalized quark-gluon plasma: We support the idea that there is no dark age in relativistic heavy-ion collisions.

Successional change in species composition alters climate sensitivity of grassland productivity.

PubMed

Shi, Zheng; Lin, Yang; Wilcox, Kevin R; Souza, Lara; Jiang, Lifen; Jiang, Jiang; Jung, Chang Gyo; Xu, Xia; Yuan, Mengting; Guo, Xue; Wu, Liyou; Zhou, Jizhong; Luo, Yiqi

2018-05-31

Succession theory predicts altered sensitivity of ecosystem functions to disturbance (i.e., climate change) due to the temporal shift in plant community composition. However, empirical evidence in global change experiments is lacking to support this prediction. Here, we present findings from an 8-year long-term global change experiment with warming and altered precipitation manipulation (double and halved amount). First, we observed a temporal shift in species composition over 8 years, resulting in a transition from an annual C 3 -dominant plant community to a perennial C 4 -dominant plant community. This successional transition was independent of any experimental treatments. During the successional transition, the response of aboveground net primary productivity (ANPP) to precipitation addition magnified from neutral to +45.3%, while the response to halved precipitation attenuated substantially from -17.6% to neutral. However, warming did not affect ANPP in either state. The findings further reveal that the time-dependent climate sensitivity may be regulated by successional change in species composition, highlighting the importance of vegetation dynamics in regulating the response of ecosystem productivity to precipitation change. © 2018 John Wiley & Sons Ltd.

OLD FIELD SUCCESSIONAL DYNAMICS FOLLOWING CESSATION OF CHRONIC DISTURBANCE

EPA Science Inventory

In grasslands dominated by warm-season grasses, community composition and successional patterns can be altered by disturbance and exotic species invasions. Our objective was to describe vegetation dynamics following cessation of a chronic disturbance (heavy grazing by cattle) in...

Current developments in the treatment of early-stage classical Hodgkin lymphoma.

PubMed

Borchmann, Sven; von Tresckow, Bastian; Engert, Andreas

2016-09-01

After presenting the current treatment recommendations for early-stage Hodgkin lymphoma, we give an overview on recently published clinical trials in this setting. Furthermore, the potential influence of current trials on the treatment of early-stage Hodgkin lymphoma and integration of newly emerging drugs into treatment protocols will be discussed. Trials attempting treatment de-escalation and omission of radiotherapy on the basis of early interim PET-scans have been disappointing so far, but results of some large trials employing this strategy are still awaited. In contrast, a more defensive strategy of starting treatment with less aggressive doxorubicine, bleomycin, vinblastine, dacarbazine (ABVD) chemotherapy and intensifying treatment in early interim PET-positive patients has shown encouraging results. New drugs such as brentuximab vedotin and immune checkpoint inhibitors have shown promising results in relapsed and refractory Hodgkin lymphoma. Clinical trials of brentuximab vedotin in early-stage Hodgkin lymphoma have been initiated. Additionally, biomarker-based treatment de-escalation might be a possible route for future improvements. The challenge for future clinical research in early-stage Hodgkin lymphoma is to continue to cure the majority of patients with first-line treatment while reducing long-term toxicity. New strategies to achieve that goal are currently being developed and will further refine treatment of early-stage Hodgkin lymphoma.

Generic Difference Between Early and Late Stages of BATSE Gamma-Ray Bursts

NASA Technical Reports Server (NTRS)

Mitrofanov, Igor G.; Litvak, Maxim L.; Anfimov, Dimitrij S.; Sanin, Anton B.; Briggs, Michael S.; Paciesas, William S.; Pendleton, Geoffrey N.; Preece, Robert D.; Meegan, Charles A.

2001-01-01

The early and late stages of gamma-ray bursts are studied in a statistical analysis of the large sample of long BATSE events. The primary peak is used as the boundary between the early and late stages of emission. Significant differences are found between the stages: the early stage is shorter, it has harder emission, and it becomes a smaller fraction of the total burst duration for burst groups of decreasing intensity.

General Differences between Early and Late Stages of BATSE Gamma-Ray Bursts

NASA Technical Reports Server (NTRS)

Mitrofanov, I. G.; Litvak, M. L.; Anfimov, D. S.; Sanin, A. B.; Briggs, M. S.; Paciesas, W. S.; Pendleton, G. N.; Preece, R. D.; Meegan, C. A.; Rose, M. Franklin (Technical Monitor)

2000-01-01

The early and late stages of gamma-ray bursts are studied in a statistical analysis of the large sample of long BATSE events. The primary peak is used as the boundary between the early and late stages of emission. Significant differences are found between the stages: the early stage is shorter, it has harder emission, and it becomes a smaller fraction of the total burst duration for burst groups of decreasing intensity.

40 CFR 797.1600 - Fish early life stage toxicity test.

Code of Federal Regulations, 2014 CFR

2014-07-01

... the test solution concentrations. The test terminates following 60 days of post-hatch exposure (for an... 40 Protection of Environment 32 2014-07-01 2014-07-01 false Fish early life stage toxicity test... Fish early life stage toxicity test. (a) Purpose. This guideline is intended to be used for assessing...

40 CFR 797.1600 - Fish early life stage toxicity test.

Code of Federal Regulations, 2011 CFR

2011-07-01

... the test solution concentrations. The test terminates following 60 days of post-hatch exposure (for an... 40 Protection of Environment 32 2011-07-01 2011-07-01 false Fish early life stage toxicity test... Fish early life stage toxicity test. (a) Purpose. This guideline is intended to be used for assessing...

Nitrogen Fixation Inputs in Pasture and Early Successional Forest in the Brazilian Amazon Region: Evidence From a Claybox Mesocosm Study

NASA Astrophysics Data System (ADS)

Davidson, Eric A.; Markewitz, Daniel; de O. Figueiredo, Ricardo; de Camargo, Plínio B.

2018-02-01

The role of biological nitrogen fixation (BNF) during secondary forest succession and in tropical pastures has been investigated and debated for several decades. Here we present results of a replicated experimental study in a degraded cattle pasture of eastern Amazonia using mass balance and a 15N tracer in lined soil pit mesocosms with three treatments: (1) plant-free control plots, (2) pasture grass Brachiaria brizantha, and (3) regrowth of early successional secondary forest species. Accumulation of N in grass biomass slightly exceeded estimates of net N mineralization from the plant-free control plots but was within the margin of error, so inputs of BNF may not have been needed. In contrast, the secondary forest vegetation accumulated about 3 times as much biomass N annually as the net N mineralization estimate, suggesting at least some role for BNF. Based on isotopic and mass measurements of N-fixing species, BNF was estimated to contribute at least 27 ± 3% of mean annual plant uptake in the secondary forest regrowth vegetation plots. Although BNF is probably important for recuperation of tropical secondary forests following land use change, the majority of the N taken up by both grasses and secondary forest regrowth arose from mineralization of the stocks of soil N.

Interannual Variations in Ecosystem Oxidative Ratio in Croplands, Deciduous Forest, Coniferous Forest, and Early Successional Forest Ecosystems

NASA Astrophysics Data System (ADS)

Masiello, C. A.; Hockaday, W. C.; Gallagher, M. E.; Calligan, L.

2009-12-01

Ecosystem net primary productivity (NPP) can vary significantly with annual variations in precipitation and temperature. These climate variations can also drive changes in plant carbon allocation patterns. Shifting allocation patterns can lead to variation in net ecosystem biochemical stocks (e.g. kg cellulose, lignin, protein, and lipid/ha), which can in turn lead to shifts in ecosystem oxidative ratio (OR). OR is the molar ratio of O2 released : CO2 fixed during biosynthesis. Major plant biochemicals vary substantially in oxidative ratio, ranging from average organic acid OR values of 0.75 to average lipid OR values of 1.37 (Masiello et al., 2008). OR is a basic property of ecosystem biochemistry, and is also an essential variable needed to constrain the size of the terrestrial biospheric carbon sink (Keeling et al., 1996). OR is commonly assumed to be 1.10 (e.g. Prentice et al., 2001), but small variations in net ecosystem OR can drive large errors in estimates of the size of the terrestrial carbon sink (Randerson et al., 2006). We hypothesized that interannual changes in climate may drive interannual variation in ecosystem OR values. Working at Kellogg Biological Station NSF LTER, we measured the annual average OR of coniferous and deciduous forests, an early successional forest, and croplands under both corn and soy. There are clear distinctions between individual ecosystems (e.g., the soy crops have a higher OR than the corn crops, and the coniferous forests have a higher OR than the deciduous forests), but the ecosystems themselves retained remarkably constant annual OR values between 1998 and 2008.

Trait-mediated assembly processes predict successional changes in community diversity of tropical forests.

PubMed

Lasky, Jesse R; Uriarte, María; Boukili, Vanessa K; Chazdon, Robin L

2014-04-15

Interspecific differences in relative fitness can cause local dominance by a single species. However, stabilizing interspecific niche differences can promote local diversity. Understanding these mechanisms requires that we simultaneously quantify their effects on demography and link these effects to community dynamics. Successional forests are ideal systems for testing assembly theory because they exhibit rapid community assembly. Here, we leverage functional trait and long-term demographic data to build spatially explicit models of successional community dynamics of lowland rainforests in Costa Rica. First, we ask what the effects and relative importance of four trait-mediated community assembly processes are on tree survival, a major component of fitness. We model trait correlations with relative fitness differences that are both density-independent and -dependent in addition to trait correlations with stabilizing niche differences. Second, we ask how the relative importance of these trait-mediated processes relates to successional changes in functional diversity. Tree dynamics were more strongly influenced by trait-related interspecific variation in average survival than trait-related responses to neighbors, with wood specific gravity (WSG) positively correlated with greater survival. Our findings also suggest that competition was mediated by stabilizing niche differences associated with specific leaf area (SLA) and leaf dry matter content (LDMC). These drivers of individual-level survival were reflected in successional shifts to higher SLA and LDMC diversity but lower WSG diversity. Our study makes significant advances to identifying the links between individual tree performance, species functional traits, and mechanisms of tropical forest succession.

Long-term sustainability in Davis Late Successional Reserve

Treesearch

Jim Stone; Joan Kittrell

2004-01-01

A pilot watershed analysis along with the Davis Late Successional Reserve analysis in the range of the northern spotted owl identified potential loss of suitable habitat, reduction in the numbers of large trees, and lack of replacements for large trees. A variety of silvicultural thinning techniques has been used to address these important issues and to move toward a...

Hepatocellular carcinoma: early-stage management challenges

PubMed Central

Erstad, Derek J; Tanabe, Kenneth K

2017-01-01

Hepatocellular carcinoma (HCC) is a major cause of cancer death and is increasing in incidence. This review focuses on HCC surveillance and treatment of early-stage disease, which are essential to improving outcomes. Multiple societies have published HCC surveillance guidelines, but screening efforts have been limited by noncompliance and overall lack of testing for patients with undiagnosed chronic liver disease. Treatment of early-stage HCC has become increasingly complex due to expanding therapeutic options and better outcomes with established treatments. Surgical indications for HCC have broadened with improved preoperative liver testing, neoadjuvant therapy, portal vein embolization, and perioperative care. Advances in post-procedural monitoring have improved efficacies of transarterial chemoembolization and radiofrequency ablation, and novel therapies involving delivery of radiochemicals are being studied in small trials. Finally, advances in liver transplantation have allowed for expanded indications beyond Milan criteria with non-inferior outcomes. More clinical trials evaluating new therapies and multimodal regimens are necessary to help clinicians design better treatment algorithms and improve outcomes. PMID:28721349

Can we create and sustain late successional attributes in interior ponderosa pine stands? Large-scale ecological research studies in northeastern California

Treesearch

William W. Oliver

2001-01-01

Conflicts over changing demands on our increasingly scarce stands of late successional ponderosa pine could be abated by increasing the proportion of stands with late successional attributes in the forest land base. However, we don't know whether these attributes can be developed through the management of younger stands. Nor do we know whether late successional...

A Four Stage Approach to Early Childhood Intervention.

ERIC Educational Resources Information Center

Haber, Julian S.

This paper describes a model for the involvement of primary health care personnel in the identification and treatment of developmental disabilities as a part of early childhood intervention programs. The integrated multidisciplinary model is divided into four stages. During the first stage an assignment of prenatal, perinatal, and postnatal risk…

Notch and Delta mRNAs in early-stage and mid-stage Drosophila embryos exhibit complementary patterns of protein producing potentials

PubMed Central

Shepherd, Andrew; Wesley, Uma; Wesley, Cedric

2010-01-01

Notch and Delta proteins generate Notch signaling that specifies cell fates during animal development. There is an intriguing phenomenon in Drosophila embryogenesis that has not received much attention and whose significance to embryogenesis is unknown. Notch and Delta mRNAs expressed in early-stage embryos are shorter than their counterparts in mid-stage embryos. We show here that the difference in sizes is due to mRNA 3′ processing at alternate polyadenylation sites. While the early-stage Notch mRNA has a lower protein-producing potential than the mid-stage Notch mRNA, the early-stage Delta mRNA has a higher protein-producing potential than the mid-stage Delta mRNA. Our data can explain the complementary patterns of Notch and Delta protein levels in early-stage and mid-stage embryos. Our data also raise the possibility that the manner and regulation of Notch signaling change in the course of embryogenesis and that this change is effected by 3′ UTR and mRNA 3′ processing factors. PMID:20201103

On the balance between niche and neutral processes as drivers of community structure along a successional gradient: insights from alpine and sub-alpine meadow communities.

PubMed

Chu, Cheng-Jin; Wang, You-Shi; Du, Guo-Zhen; Maestre, Fernando T; Luo, Yan-Jiang; Wang, Gang

2007-10-01

Neutral theory predicts that the diversity and relative abundance of species in ecological communities do not depend on their specific traits. This prediction remains controversial, as many studies suggest that variations in the niches of species determine the structure of communities. The aim of this study was to test empirically the relative importance of niche and neutral processes as drivers of species abundance within plant communities along a successional gradient. Information on the abundance (density and frequency) and traits (aboveground individual biomass and seed mass) of > 90 species was collected in alpine and sub-alpine meadows of the Tibet Plateau (China). A successional gradient (1, 3, 15 and 30 years after abandonment) was established in a sub-alpine meadow. The relationships between species traits and their abundance were evaluated using regression models. Seed mass was negatively related to both species density (r = -0.6270, P < 0.001) and frequency (r = -0.5335, P = 0.005) in the 1-year meadow. Such relationships disappeared along the successional gradient evaluated (P > 0.07 in the 3-, 15- and 30-year meadows). Data gathered in all sites showed a significant negative relationship between the average individual biomass of a given species and its density within the community (r < -0.30, P < 0.025 in all cases). The results show that seed mass was a key driver of species abundance in early successional communities, and that niche forces may become more important as succession progresses. They also indicate that predictions from neutral theory, in its current form, do not hold for the meadow communities studied.

Early stages of Ostwald ripening

NASA Astrophysics Data System (ADS)

Shneidman, Vitaly A.

2013-07-01

The Becker-Döring (BD) nucleation equation is known to predict a narrow double-exponential front (DEF) in the distribution of growing particles over sizes, which is due to early transient effects. When mass conservation is included, nucleation is eventually exhausted while independent growth is replaced by ripening. Despite the enormous difference in the associated time scales, and the resulting demand on numerics, within the generalized BD model the early DEF is shown to be crucial for the selection of the unique self-similar Lifshitz-Slyozov-Wagner asymptotic regime. Being preserved till the latest stages of growth, the DEF provides a universal part of the initial conditions for the ripening problem, regardless of the mass exchange mechanism between the nucleus and the matrix.

Influence of hope, social support, and self-esteem in early stage dementia.

PubMed

Cotter, Valerie T; Gonzalez, Elizabeth W; Fisher, Kathleen; Richards, Kathy C

2018-02-01

Background People in the early stages of dementia adjust to the illness through stages of awareness, coping, and evaluation. Studies have found that hope, social support, and self-esteem facilitate coping, adjustment, and adaptation in chronic illness. Objective The purpose of this descriptive study was to examine the relationships between hope, social support, and self-esteem in individuals with early stage dementia. Methods Data were obtained from 53 individuals with early stage dementia. The scores on the Herth Hope Index, Social Support Questionnaire Short-Form, and the State Self-Esteem Scale were analyzed using linear regression. Results Hope was moderately associated with self-esteem ( r = .49, p < .001). Hope accounted for 25% of the variance in self-esteem and was a key component in predicting self-esteem. No significant relationship was found between social support and self-esteem. Conclusion Findings suggest that hope may be an important factor to help individuals manage potential threats to self-esteem in the experience of early stage dementia. Strategies to inspire hope and then enhance self-esteem are promising for individuals living with early stage dementia.

Ecological and financial assessment of late-successional reserve management.

Treesearch

Susan Stevens Hummel; R. James Barbour; Paul F. Hessburg; John F. Lehmkuhl

2001-01-01

This paper documents methods for assessing the potential effects of variable-intensity management in late-successional reserves (LSRs) and provides an example (the Gotchen LSR) from the Cascade Range in eastern Washington. The Gotchen LSR study investigates changes in forest vegetation associated with silvicultural treatments, and how different treatment combinations...

All-optical photoacoustic imaging and detection of early-stage dental caries

NASA Astrophysics Data System (ADS)

Sampathkumar, Ashwin; Hughes, David A.; Longbottom, Chris; Kirk, Katherine J.

2015-02-01

Dental caries remain one of the most common oral diseases in the world. Current detection methods, such as dental explorer and X-ray radiography, suffer from poor sensitivity and specificity at the earliest (and reversible) stages of the disease because of the small size (< 100 microns) of early-stage lesions. We have developed a fine-resolution (480 nm), ultra-broadband (1 GHz), all-optical photoacoustic imaging (AOPAI) system to image and detect early stages of tooth decay. This AOPAI system provides a non-contact, non-invasive and non-ionizing means of detecting early-stage dental caries. Ex-vivo teeth exhibiting early-stage, white-spot lesions were imaged using AOPAI. Experimental scans targeted each early-stage lesion and a reference healthy enamel region. Photoacoustic (PA) signals were generated in the tooth using a 532-nm pulsed laser and the light-induced broadband ultrasound signal was detected at the surface of the tooth with an optical path-stabilized Michelson interferometer operating at 532 nm. The measured time-domain signal was spatially resolved and back-projected to form 2D and 3D maps of the lesion using k-wave reconstruction methods. Experimental data collected from areas of healthy and diseased enamel indicate that the lesion generated a larger PA response compared to healthy enamel. The PA-signal amplitude alone was able to detect a lesion on the surface of the tooth. However, time- reversal reconstructions of the PA scans also quantitatively depicted the depth of the lesion. 3D PA reconstruction of the diseased tooth indicated a sub-surface lesion at a depth of 0.6 mm, in addition to the surface lesion. These results suggest that our AOPAI system is well suited for rapid clinical assessment of early-stage dental caries. An overview of the AOPAI system, fine-resolution PA and histology results of diseased and healthy teeth will be presented.

Do natural disturbances or the forestry practices that follow them convert forests to early successional communities?

Treesearch

J. Stephen Brewer; Christine Bertz; Jeffery B. Cannon; Jason D. Chesser; Erynn E. Maynard

2012-01-01

Stand-replacing natural disturbances in mature forests are traditionally seen as events that cause forests to revert to early stages of succession and maintain species diversity. In some cases, however, such transitions could be an artifact of salvage logging and may increase biotic homogenization. We present initial (two-year) results of a study of the effects of...

Efficient harvesting methods for early-stage snake and turtle embryos.

PubMed

Matsubara, Yoshiyuki; Kuroiwa, Atsushi; Suzuki, Takayuki

2016-04-01

Reptile development is an intriguing research target for understating the unique morphogenesis of reptiles as well as the evolution of vertebrates. However, there are numerous difficulties associated with studying development in reptiles. The number of available reptile eggs is usually quite limited. In addition, the reptile embryo is tightly adhered to the eggshell, making it a challenge to isolate reptile embryos intact. Furthermore, there have been few reports describing efficient procedures for isolating intact embryos especially prior to pharyngula stage. Thus, the aim of this review is to present efficient procedures for obtaining early-stage reptilian embryos intact. We first describe the method for isolating early-stage embryos of the Japanese striped snake. This is the first detailed method for obtaining embryos prior to oviposition in oviparous snake species. Second, we describe an efficient strategy for isolating early-stage embryos of the soft-shelled turtle. © 2016 Japanese Society of Developmental Biologists.

Src Kinase: A Novel Target of Early-Stage ER-Negative Breast Cancer

DTIC Science & Technology

2012-03-01

patients with early stage ErbB2-overexpressing biopsies and ER- atypia . 13 REFERENCES: 1. Jordan VC. Tamoxifen for breast cancer prevention. Proc Soc...Summary01-03-2012 Src Kinase: A Novel Target of Early-Stage ER-Negative Breast Cancer Shalini Jain University of Texas M.D. Anderson Cancer Center Houston...SUBTITLE “Src Kinase: A Novel Target of Early-Stage ER-Negative Breast Cancer” 5a. CONTRACT NUMBER W81XWH-11-1-0004 5b. GRANT NUMBER

Usability of tablet computers by people with early-stage dementia.

PubMed

Lim, Fabian S; Wallace, Tim; Luszcz, Mary A; Reynolds, Karen J

2013-01-01

Tablet computers are generally associated with an intuitive interface. The adoption and use of tablet computers within the early-stage dementia context could potentially assist in daily living and provide users with a source for leisure activities and social networking. As dementia mainly affects the older adult population, it is expected that many people with dementia and even their carers do not use tablet computers as part of their everyday living. This paper explores the usability of tablet computers within the early-stage dementia context as a source of leisure for people with dementia. The main advantage of the use of tablet computers in this manner is to provide carers some reprieve from the constant care and attention often required in caring for people with dementia. Seven-day in-home trials were conducted to determine whether people with early-stage dementia were -capable of using a tablet computer independently. Twenty-one people with early-stage dementia and carer dyads participated in the trial. Feedback was gathered through questionnaires from both the person with dementia and their carer regarding the use of a tablet computer as part of their everyday living. Approximately half the participants with dementia were able to engage with and use the tablet computer independently, which proved to be helpful to their carers. No significant traits were observed to help identify those who were less likely to use a tablet computer. Carer relief was quantified by the amount of time participants with dementia spent using the device without supervision. The results and feedback from the trial provide significant insights to introducing new technology within the early-stage dementia context. Users' needs must be considered on a case-by-case basis to successfully facilitate the uptake of tablet computers in the dementia context. The trial has provided sufficient justification to further explore more uses of tablet computers in the dementia context, and not just for

Surgical Staging of Early Stage Endometrial Cancer: Comparison Between Laparotomy and Laparoscopy

PubMed Central

Api, Murat; Kayatas, Semra; Boza, Aysen Telce; Nazik, Hakan; Adiguzel, Cevdet; Guzin, Kadir; Eroglu, Mustafa

2013-01-01

Background The aim of the present study was to compare the laparotomy (LT) and laparoscopy (LS) in patients who undergone surgical staging for early stage endometrium cancer. Methods Retrospective data were collected and analyzed for amount of intraoperative bleeding, complication rates, total resected and laterality specific number of lymph nodes and duration of operation in patients operated with either LT or LS. Results Seventy-nine stage I endometrium cancer patients were found to be eligible for the trial purposes: 58 (73.4%) treated by LT and 21 (26.6%) treated by LS. The number of lymph nodes was similar in LT (8.9 ± 5.3) and LS (9.2 ± 4.8) (P = 0.8). In LT group, there was no difference in the number of lymph nodes between the right and left sides (10 ± 5.8 and 8.7 ± 4.8 respectively, P = 0.19); in LS group, the number of lymph nodes resected from the right side was higher than the left side (9.8 ± 5 and 7 ± 3.5 respectively, P = 0.039). The amount of intraoperative bleeding and hospitalization period were significantly higher in LT group. Seventy-nine patients had a median follow-up of 30 months. The two groups were similar for disease-free survival (P = 0.46, log rank test). Conclusions There was no significant difference between the two methods in terms of number of total resected lymph nodes. In early stage endometrial carcinoma, LS has provided adequate staging and similar survival rates with LT. PMID:29147363

DNA Copy Number Signature to Predict Recurrence in Early Stage Ovarian Cancer

DTIC Science & Technology

2016-08-01

AWARD NUMBER: W81XWH-14-1-0194 TITLE: DNA Copy Number Signature to Predict Recurrence in Early-Stage Ovarian Cancer PRINCIPAL INVESTIGATOR...SUBTITLE 5a. CONTRACT NUMBER DNA Copy Number Signature to Predict Recurrence in Early-Stage Ovarian Cancer 5b. GRANT NUMBER W81XWH-14-1-0194 5c. PROGRAM...determine the copy number gain and loss for early stage high grade ovarian cancers through IlluminaHumanOmniExpress-FFPE BeadChip system • Subtask 1 DNA

Formation of a successional dental lamina in the zebrafish (Danio rerio): support for a local control of replacement tooth initiation.

PubMed

Huysseune, Ann

2006-01-01

In order to test whether the formation of a replacement tooth bud in a continuously replacing dentition is linked to the functional state of the tooth predecessor, I examined the timing of development of replacement teeth with respect to their functional predecessors in the pharyngeal dentition of the zebrafish. Observations based on serial semithin sections of ten specimens, ranging in age from four week old juveniles to adults, indicate that (i) a replacement tooth germ develops at the distal end of an epithelial structure, called the successional dental lamina, budding off from the crypt epithelium surrounding the erupted part of a functional tooth; (ii) there appears to be a developmental link between the eruption of a tooth and the formation of a successional dental lamina and (iii) there can be a time difference between successional lamina formation and initiation of the new tooth germ, i.e., the successional dental lamina can remain quiescent for some time. The data suggest that the formation of a successional lamina and the differentiation of a replacement tooth germ from this lamina, are two distinct phases of a process and possibly under a different control. The strong spatio-temporal coincidence of eruption of a tooth and development of a successional dental lamina is seen as evidence for a local control over tooth replacement.

Management of Early Stage, High-Risk Endometrial Carcinoma: Preoperative and Surgical Considerations

PubMed Central

Pettigrew, Gaetan

2013-01-01

Endometrial cancer is the most common gynecologic malignancy in the developed world. Most cases are diagnosed at an early stage and have low-grade histology, portending an overall excellent prognosis. There exists a subgroup of patients with early, high-risk disease, whose management remains controversial, as current data is clouded by inclusion of early stage tumors with different high-risk features for recurrence, unstandardized protocols for surgical staging, and an evolving staging system by which we are grouping these patients. Here, we present preoperative and intraoperative considerations that should be taken into account when planning surgical management for this population of patients. PMID:23878545

Multimodal imaging findings in 'hyper-early' stage MEWDS.

PubMed

Cahuzac, Armelle; Wolff, Benjamin; Mathis, Thibaud; Errera, Marie-Hélène; Sahel, José-Alain; Mauget-Faÿsse, Martine

2017-10-01

To describe a new stage of multiple evanescent white dot syndrome (MEWDS), occurring at a very early phase of the disease. Retrospective analysis of clinical, angiographic and tomographic findings in four patients with 'hyper-early' stage MEWDS. In four patients seen within 1 week of the onset of symptoms, fundus analysis revealed macular granity and the classic yellow-white dots, some having no corresponding hyperautofluorescent pattern. Spectral-domain optical coherence tomography (SD-OCT) showed central foveal disruption of the ellipsoid zone (EZ) and interdigitation layer with a hyper-reflective dome-shaped lesion. In two patients, fluorescein angiography (FA) revealed an intermediate hypofluorescent perimacular halo, whereas late indocyanine green angiography (ICGA) showed a hyperfluorescent halo as well as the classic MEWDS features. After a few days, the EZ disruption appeared complete on OCT and fundus autofluorescence (FAF) in all patients. Visual acuity, OCT and FAF findings had fully recovered within 3 months. We have shown a new feature of MEWDS on FAF, OCT, FA and ICGA, corresponding to a very early stage of the disease. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Unraveling Mixed Hydrate Formation: Microscopic Insights into Early Stage Behavior.

PubMed

Hall, Kyle Wm; Zhang, Zhengcai; Kusalik, Peter G

2016-12-29

The molecular-level details of mixed hydrate nucleation remain unclear despite the broad implications of this process for a variety of scientific domains. Through analysis of mixed hydrate nucleation in a prototypical CH 4 /H 2 S/H 2 O system, we demonstrate that high-level kinetic similarities between mixed hydrate systems and corresponding pure hydrate systems are not a reliable basis for estimating the composition of early stage mixed hydrate nuclei. Moreover, we show that solution compositions prior to and during nucleation are not necessarily effective proxies for the composition of early stage mixed hydrate nuclei. Rather, microscopic details, (e.g., guest-host interactions and previously neglected cage types) apparently play key roles in determining early stage behavior of mixed hydrates. This work thus provides key foundational concepts and insights for understanding mixed hydrate nucleation.

Driving behaviors in early stage dementia: a study using in-vehicle technology.

PubMed

Eby, David W; Silverstein, Nina M; Molnar, Lisa J; LeBlanc, David; Adler, Geri

2012-11-01

According to the Alzheimer's Association (2011), (1) in 8 people age 65 and older, and about one-half of people age 85 and older, have Alzheimer's disease in the United States (US). There is evidence that drivers with Alzheimer's disease and related dementias are at an increased risk for unsafe driving. Recent advances in sensor, computer, and telecommunication technologies provide a method for automatically collecting detailed, objective information about the driving performance of drivers, including those with early stage dementia. The objective of this project was to use in-vehicle technology to describe a set of driving behaviors that may be common in individuals with early stage dementia (i.e., a diagnosis of memory loss) and compare these behaviors to a group of drivers without cognitive impairment. Seventeen drivers with a diagnosis of early stage dementia, who had completed a comprehensive driving assessment and were cleared to drive, participated in the study. Participants had their vehicles instrumented with a suite of sensors and a data acquisition system, and drove 1-2 months as they would under normal circumstances. Data from the in-vehicle instrumentation were reduced and analyzed, using a set of algorithms/heuristics developed by the research team. Data from the early stage dementia group were compared to similar data from an existing dataset of 26 older drivers without dementia. The early stage dementia group was found to have significantly restricted driving space relative to the comparison group. At the same time, the early stage dementia group (which had been previously cleared by an occupational therapist as safe to drive) drove as safely as the comparison group. Few safety-related behavioral errors were found for either group. Wayfinding problems were rare among both groups, but the early stage dementia group was significantly more likely to get lost. Copyright © 2011 Elsevier Ltd. All rights reserved.

Bioaccumulation of lipophilic substances in fish early life stages

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petersen, G.I.; Kristensen, P.

1998-07-01

Accumulation of {sup 14}C-labeled polycyclic aromatic hydrocarbons, naphthalene, phenanthrene, pyrene, and benzo(a)pyrene and polychlorinated biphenyl (PCB) congeners PCB 31 and PCB 105 with a log octanol/water partition coefficient (K{sub ow}) range from 3.37 to 6.5 was investigated in eggs and larvae of zebra fish (Brachydanio rerio), and in larvae of cod (Gadus morhua), herring (Clupea harengus), and turbot (Scophthalmus maximus). Significant differences in the uptake and elimination rate constants between eggs and larvae of zebra fish were seen. The low rate of uptake and the lower elimination rate of eggs did, however, lead to bioconcentration factors (BCFs) comparable to thosemore » for larvae. As biotransformation of xenobiotics in embryonic and larval stages was indicated to be insignificant compared to juvenile/adult stages, body burdens of readily biotransformed chemicals may be higher in fish early life stages. Because weight and lipid content did not differ much between the investigated species, the main reason for the variability in BCFs between marine species and freshwater species was considered to be caused by differences in exposure temperatures that affect the degree of biotransformation. Due to the smaller size of larvae and thus an increased total surface of the membranes per unit fish weight, steady-state conditions were reached at a faster r/ate in early life stages than in juvenile/adult life stages. The lipid-normalized bioconcentration factors (BCF{sub L}) were linearly related to K{sub ow} but BCF{sub L} was, in general, higher than K{sub ow}, indicating that octanol is not a suitable surrogate for fish lipids. Differences in bioconcentration kinetics between larvae and juvenile/adult life stages are considered to be the main reason for the higher sensitivity, with respect to external effect concentrations, generally obtained for early life stages of fish.« less

Developing desired future conditions with the landscape management system: A case study of the Gotchen Late Successional Reserve

Treesearch

R. Mendez-Treneman; S. Hummel; G. Porterie; C. D. Oliver

2001-01-01

Changing public values have led to federal land management direction like the Northwest Forest Plan with major land allocations for late successional forest habitat. Restoration silviculture is a tool for maintaining optimum habitat despite risk of catastrophic disturbance due to the combined impact of fire, insects and disease. The Gotchen Late Successional Reserve (...

Collaboration with Pharma Will Introduce Nanotechnologies in Early Stage Drug Development | FNLCR Staging

Cancer.gov

The Frederick National Lab has begun to assist several major pharmaceutical companies in adopting nanotechnologies in early stage drug development, when the approach is most efficient and cost-effective. For some time, the national lab’s Nanotechno

Balancing risk and benefit in early-stage classical Hodgkin lymphoma.

PubMed

Bröckelmann, Paul J; Sasse, Stephanie; Engert, Andreas

2018-04-12

With defined chemotherapy and radiotherapy (RT) and risk-adapted treatment, early-stage classical Hodgkin lymphoma (HL) has become curable in a majority of patients. Hence, a major current goal is to reduce treatment-related toxicity while maintaining long-term disease control. Patients with early-stage favorable disease (ie, limited stage without risk factors [RFs]) are frequently treated with 2 cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine (2×ABVD) followed by 20-Gy involved-field or involved-site RT (IF/ISRT). In patients with early-stage unfavorable disease (ie, limited stage with RFs), 4 cycles of chemotherapy are usually consolidated with 30-Gy IF/ISRT. Compared with 4×ABVD, 2 cycles of bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone (2×BEACOPP escalated ) followed by 2×ABVD improved 5-year progression-free survival (PFS), with similar 5-year overall survival. Recently, treatment strategies based on [ 18 F]fluorodeoxyglucose positron emission tomography (PET) response were evaluated. In early-stage unfavorable HL, a majority of patients achieved a negative interim PET after 2×ABVD and an excellent outcome after 4×ABVD, whereas in those with a positive interim PET, 2×BEACOPP escalated improved 5-year PFS. Furthermore, a PET-guided RT approach was evaluated to decrease long-term toxicity. Although both the RAPID and H10 trials reported poorer disease control without RT, PET-guided omission of RT can constitute a valid therapeutic option in patients with an increased risk of RT-associated toxicity (eg, because of sex, age, or disease localization). Implementation of drugs such as the anti-CD30 antibody-drug conjugate brentuximab vedotin or the anti-programmed death 1 antibodies nivolumab or pembrolizumab might allow further reduction of overall mortality and improve quality of life in affected patients. © 2018 by The American Society of Hematology.

Minimally invasive transcanal myringotomy for pediatric early stage congenital cholesteatoma.

PubMed

Jang, Chul Ho; Jung, Eun Kyung; Sung, Chung Man; Kim, Seung Beom; Kim, Young Yoon; Seong, Jong Yuap; Kang, Sung Hoon; Cho, Yong Beom

2016-11-01

Recently, minimally invasive transcanal myringotomy (MITM), which is a useful surgical technique for early stage congenital cholesteatoma (CC) in children, was introduced. The purpose of this study is to evaluate the short-term surgical results of MITM in pediatric early stage CC. We retrospectively reviewed the charts of 24 patients who underwent MITM between January 2013 and October 2015. The patients' ages ranged from 1 to 16 years (mean, 2.6 years). There were 17 male and 7 female patients. The right side (n = 13) was affected twice as often as the left side (n = 11). The most common site was the anterosuperior quadrant (15 cases). The diameter of the CC on axial computed tomography images ranged from 2.8 to 5.7 mm (mean, 3.9 mm). CCs were graded according to Potsic's system: 18 cases were classified as stage I, 3 case as stage II, and 3 cases as stage III. AllCCs except 1 were closed type. In21 patients, the tympanic membrane closed naturally without recurrence. Three patients showed small persistent dry perforation. Natural closure occurred in these patients, who were treated with paper patches. MITM is a simple, effective technique for removing an early stage CC from the middle ear, and it can minimize operative time, length of hospitalization, and postoperative morbidity. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

The early stages of duplicate gene evolution

PubMed Central

Moore, Richard C.; Purugganan, Michael D.

2003-01-01

Gene duplications are one of the primary driving forces in the evolution of genomes and genetic systems. Gene duplicates account for 8–20% of the genes in eukaryotic genomes, and the rates of gene duplication are estimated at between 0.2% and 2% per gene per million years. Duplicate genes are believed to be a major mechanism for the establishment of new gene functions and the generation of evolutionary novelty, yet very little is known about the early stages of the evolution of duplicated gene pairs. It is unclear, for example, to what extent selection, rather than neutral genetic drift, drives the fixation and early evolution of duplicate loci. Analysis of recently duplicated genes in the Arabidopsis thaliana genome reveals significantly reduced species-wide levels of nucleotide polymorphisms in the progenitor and/or duplicate gene copies, suggesting that selective sweeps accompany the initial stages of the evolution of these duplicated gene pairs. Our results support recent theoretical work that indicates that fates of duplicate gene pairs may be determined in the initial phases of duplicate gene evolution and that positive selection plays a prominent role in the evolutionary dynamics of the very early histories of duplicate nuclear genes. PMID:14671323

Clinical Practice of Adjuvant Chemotherapy in Patients with Early-Stage Epithelial Ovarian Cancer.

PubMed

Frielink, Lindy M J; Pijlman, Brenda M; Ezendam, Nicole P M; Pijnenborg, Johanna M A

2016-01-01

Adjuvant platinum-based chemotherapy improves survival in women with early-stage epithelial ovarian cancer (EOC). Yet, there is a wide variety in clinical practice. All patients diagnosed with FIGO I and IIa EOC (2006-2010) in the south of the Netherlands were analyzed. The percentage of patients that received adjuvant chemotherapy was determined as well as the comprehensiveness of staging and outcome. Forty percent (54/135) of the patients with early-stage EOC received adjuvant chemotherapy. Treatment with adjuvant chemotherapy was associated with FIGO stage, clear-cell histology and nonoptimal staging. Optimal staging was achieved in 50%, and nonoptimal staging was associated with advanced age, comorbidity and treatment in a non-referral hospital. Overall, there was no difference in outcome between patients with and without adjuvant chemotherapy. Yet, in grade 3 tumors, adjuvant chemotherapy seems beneficial. Selective treatment of patients with early-stage EOC might reduce adjuvant chemotherapy without compromising outcome. © 2016 S. Karger AG, Basel.

[Aging affects early stage direction selectivity of MT cells in rhesus monkeys].

PubMed

Liang, Zhen; Chen, Yue-Ming; Meng, Xue; Wang, Yi; Zhou, Bao-Zhuo; Xie, Ying-Ying; He, Wen-Sheng

2012-10-01

The middle temporal area (MT/V5) plays an important role in motion processing. Neurons in this area have a strongly selective response to the moving direction of objects and as such, the selectivity of MT neurons was proposed to be a neural mechanism for the perception of motion. Our previous studies have found degradation in direction selectivity of MT neurons in old monkeys, but this direction selectivity was calculated during the whole response time and the results were not able to uncover the mechanism of motion perception over a time course. Furthermore, experiments have found that direction selectivity was enhanced by attention at a later stage. Therefore, the response should be excluded in experiments with anesthesia. To further characterize the neural mechanism over a time course, we investigated the age-related changes of direction selectivity in the early stage by comparing the proportions of direction selective MT cells in old and young macaque monkeys using in vivo single-cell recording techniques. Our results show that the proportion of early-stage-direction-selective cells is lower in old monkeys than in young monkeys, and that the early stage direction bias (esDB) of old MT cells decreased relative to young MT cells. Furthermore, the proportion of MT cells having strong early stage direction selectivity in old monkeys was decreased. Accordingly, the functional degradation in the early stage of MT cells may mediate perceptual declines of old primates in visual motion tasks.

Prognostic model for survival in patients with early stage cervical cancer.

PubMed

Biewenga, Petra; van der Velden, Jacobus; Mol, Ben Willem J; Stalpers, Lukas J A; Schilthuis, Marten S; van der Steeg, Jan Willem; Burger, Matthé P M; Buist, Marrije R

2011-02-15

In the management of early stage cervical cancer, knowledge about the prognosis is critical. Although many factors have an impact on survival, their relative importance remains controversial. This study aims to develop a prognostic model for survival in early stage cervical cancer patients and to reconsider grounds for adjuvant treatment. A multivariate Cox regression model was used to identify the prognostic weight of clinical and histological factors for disease-specific survival (DSS) in 710 consecutive patients who had surgery for early stage cervical cancer (FIGO [International Federation of Gynecology and Obstetrics] stage IA2-IIA). Prognostic scores were derived by converting the regression coefficients for each prognostic marker and used in a score chart. The discriminative capacity was expressed as the area under the curve (AUC) of the receiver operating characteristic. The 5-year DSS was 92%. Tumor diameter, histological type, lymph node metastasis, depth of stromal invasion, lymph vascular space invasion, and parametrial extension were independently associated with DSS and were included in a Cox regression model. This prognostic model, corrected for the 9% overfit shown by internal validation, showed a fair discriminative capacity (AUC, 0.73). The derived score chart predicting 5-year DSS showed a good discriminative capacity (AUC, 0.85). In patients with early stage cervical cancer, DSS can be predicted with a statistical model. Models, such as that presented here, should be used in clinical trials on the effects of adjuvant treatments in high-risk early cervical cancer patients, both to stratify and to include patients. Copyright © 2010 American Cancer Society.

Large-scale Metabolomic Analysis Reveals Potential Biomarkers for Early Stage Coronary Atherosclerosis.

PubMed

Gao, Xueqin; Ke, Chaofu; Liu, Haixia; Liu, Wei; Li, Kang; Yu, Bo; Sun, Meng

2017-09-18

Coronary atherosclerosis (CAS) is the pathogenesis of coronary heart disease, which is a prevalent and chronic life-threatening disease. Initially, this disease is not always detected until a patient presents with seriously vascular occlusion. Therefore, new biomarkers for appropriate and timely diagnosis of early CAS is needed for screening to initiate therapy on time. In this study, we used an untargeted metabolomics approach to identify potential biomarkers that could enable highly sensitive and specific CAS detection. Score plots from partial least-squares discriminant analysis clearly separated early-stage CAS patients from controls. Meanwhile, the levels of 24 metabolites increased greatly and those of 18 metabolites decreased markedly in early CAS patients compared with the controls, which suggested significant metabolic dysfunction in phospholipid, sphingolipid, and fatty acid metabolism in the patients. Furthermore, binary logistic regression showed that nine metabolites could be used as a combinatorial biomarker to distinguish early-stage CAS patients from controls. The panel of nine metabolites was then tested with an independent cohort of samples, which also yielded satisfactory diagnostic accuracy (AUC = 0.890). In conclusion, our findings provide insight into the pathological mechanism of early-stage CAS and also supply a combinatorial biomarker to aid clinical diagnosis of early-stage CAS.

Selection occurs within linear fruit and during the early stages of reproduction in Robinia pseudoacacia

PubMed Central

2014-01-01

Background Pollen donor compositions differ during the early stages of reproduction due to various selection mechanisms. In addition, ovules linearly ordered within a fruit have different probabilities of reaching maturity. Few attempts, however, have been made to directly examine the magnitude and timing of selection, as well as the mechanisms during early life stages and within fruit. Robinia pseudoacacia, which contains linear fruit and non-random ovule maturation and abortion patterns, has been used to study the viability of selection within fruit and during the early stages of reproduction. To examine changes in the pollen donor composition during the early stages of reproduction and of progeny originating from different positions within fruit, paternity analyses were performed for three early life stages (aborted seeds, mature seeds and seedlings) in the insect-pollinated tree R. pseudoacacia. Results Selection resulted in an overall decrease in the level of surviving selfed progeny at each life stage. The greatest change was observed between the aborted seed stage and mature seed stage, indicative of inbreeding depression (the reduced fitness of a given population that occurs when related individual breeding was responsible for early selection). A selective advantage was detected among paternal trees. Within fruits, the distal ends showed higher outcrossing rates than the basal ends, indicative of selection based on the order of seeds within the fruit. Conclusions Our results suggest that selection exists both within linear fruit and during the early stages of reproduction, and that this selection can affect male reproductive success during the early life stages. This indicates that tree species with mixed-mating systems may have evolved pollen selection mechanisms to increase the fitness of progeny and adjust the population genetic composition. The early selection that we detected suggests that inbreeding depression caused the high abortion rate and low

Selection occurs within linear fruit and during the early stages of reproduction in Robinia pseudoacacia.

PubMed

Yuan, Cun-Quan; Sun, Yu-Han; Li, Yun-Fei; Zhao, Ke-Qi; Hu, Rui-Yang; Li, Yun

2014-03-21

Pollen donor compositions differ during the early stages of reproduction due to various selection mechanisms. In addition, ovules linearly ordered within a fruit have different probabilities of reaching maturity. Few attempts, however, have been made to directly examine the magnitude and timing of selection, as well as the mechanisms during early life stages and within fruit. Robinia pseudoacacia, which contains linear fruit and non-random ovule maturation and abortion patterns, has been used to study the viability of selection within fruit and during the early stages of reproduction. To examine changes in the pollen donor composition during the early stages of reproduction and of progeny originating from different positions within fruit, paternity analyses were performed for three early life stages (aborted seeds, mature seeds and seedlings) in the insect-pollinated tree R. pseudoacacia. Selection resulted in an overall decrease in the level of surviving selfed progeny at each life stage. The greatest change was observed between the aborted seed stage and mature seed stage, indicative of inbreeding depression (the reduced fitness of a given population that occurs when related individual breeding was responsible for early selection). A selective advantage was detected among paternal trees. Within fruits, the distal ends showed higher outcrossing rates than the basal ends, indicative of selection based on the order of seeds within the fruit. Our results suggest that selection exists both within linear fruit and during the early stages of reproduction, and that this selection can affect male reproductive success during the early life stages. This indicates that tree species with mixed-mating systems may have evolved pollen selection mechanisms to increase the fitness of progeny and adjust the population genetic composition. The early selection that we detected suggests that inbreeding depression caused the high abortion rate and low seed set in R. pseudoacacia.

Vegetation response to early holocene warming as an analog for current and future changes: Special section

USGS Publications Warehouse

Cole, K.L.

2010-01-01

Temperatures in southwestern North America are projected to increase 3.5-4 ??C over the next 60-90 years. This will precipitate ecological shifts as the ranges of species change in response to new climates. During this shift, rapid-colonizing species should increase, whereas slow-colonizing species will at first decrease, but eventually become reestablished in their new range. This successional process has been estimated to require from 100 to over 300 years in small areas, under a stable climate, with a nearby seed source. How much longer will it require on a continental scale, under a changing climate, without a nearby seed source? I considered this question through an examination of the response of fossil plant assemblages from the Grand Canyon, Arizona, to the most recent rapid warming of similar magnitude that occurred at the start of the Holocene, 11,700 years ago. At that time, temperatures in southwestern North America increased about 4 ??C over less than a century. Grand Canyon plant species responded at different rates to this warming climate. Early-successional species rapidly increased, whereas late-successional species decreased. This shift persisted throughout the next 2700 years. I found two earlier, less-extreme species shifts following rapid warming events around 14,700 and 16,800 years ago. Late-successional species predominated only after 4000 years or more of relatively stable temperature. These results suggest the potential magnitude, duration, and nature of future ecological changes and have implications for conservation plans, especially those incorporating equilibrium assumptions or reconstituting past conditions. When these concepts are extended to include the most rapid early-successional colonizers, they imply that the recent increases in invasive exotics may be only the most noticeable part of a new resurgence of early-successional vegetation. Additionally, my results challenge the reliability of models of future vegetation and carbon

Soil amino acid composition across a boreal forest successional sequence

Treesearch

Nancy R. Werdin-Pfisterer; Knut Kielland; Richard D. Boone

2009-01-01

Soil amino acids are important sources of organic nitrogen for plant nutrition, yet few studies have examined which amino acids are most prevalent in the soil. In this study, we examined the composition, concentration, and seasonal patterns of soil amino acids across a primary successional sequence encompassing a natural gradient of plant productivity and soil...

Three-peat NREL Intern Pushes Boundaries of Early-Stage Fuels Research on

Science.gov Websites

Early-Stage Fuels Research on Way to Master's Degree Three-peat NREL Intern Pushes Boundaries of Early -Stage Fuels Research on Way to Master's Degree January 4, 2018 Woman preparing a fuel evaluation in a constant volume combustion vessel Drew Cameron, Research Participant Program Intern, prepares a test for

Urine biomarkers in the early stages of diseases: current status and perspective.

PubMed

Jing, Jian; Gao, Youhe

2018-02-01

As a noninvasive and easily available biological fluid, the urine is becoming an important source for disease biomarker study. Change is essential for the usefulness of a biomarker. Without homeostasis mechanisms, urine can accommodate more changes, especially in the early stages of diseases. In this review, we summarize current status and discuss perspectives on the discovery of urine biomarkers in the early stages of diseases. We emphasize the advantages of urine biomarkers compared to plasma biomarkers for the diagnosis of diseases at early stages, propose a urine biomarker research roadmap, and highlight a novel membrane storage technique that enables large-scale urine sample collection and storage efficiently and economically. It is anticipated that urine biomarker studies will greatly promote early diagnosis, prevention, treatment, and prognosis of a variety of diseases, and provide strong support for translational and precision medicine.

Methods for Surgical Targeting of the STN in Early-Stage Parkinson’s Disease

PubMed Central

Camalier, Corrie R.; Konrad, Peter E.; Gill, Chandler E.; Kao, Chris; Remple, Michael R.; Nasr, Hana M.; Davis, Thomas L.; Hedera, Peter; Phibbs, Fenna T.; Molinari, Anna L.; Neimat, Joseph S.; Charles, David

2013-01-01

Patients with Parkinson’s disease (PD) experience progressive neurological decline, and future interventional therapies are thought to show most promise in early stages of the disease. There is much interest in therapies that target the subthalamic nucleus (STN) with surgical access. While locating STN in advanced disease patients (Hoehn–Yahr Stage III or IV) is well understood and routinely performed at many centers in the context of deep brain stimulation surgery, the ability to identify this nucleus in early-stage patients has not previously been explored in a sizeable cohort. We report surgical methods used to target the STN in 15 patients with early PD (Hoehn–Yahr Stage II), using a combination of image guided surgery, microelectrode recordings, and clinical responses to macrostimulation of the region surrounding the STN. Measures of electrophysiology (firing rates and root mean squared activity) have previously been found to be lower than in later-stage patients, however, the patterns of electrophysiology seen and dopamimetic macrostimulation effects are qualitatively similar to those seen in advanced stages. Our experience with surgical implantation of Parkinson’s patients with minimal motor symptoms suggest that it remains possible to accurately target the STN in early-stage PD using traditional methods. PMID:24678307

Early-stage valuation of medical devices: the role of developmental uncertainty.

PubMed

Girling, Alan; Young, Terry; Brown, Celia; Lilford, Richard

2010-08-01

At the concept stage, many uncertainties surround the commercial viability of a new medical device. These include the ultimate functionality of the device, the cost of producing it and whether, and at what price, it can be sold to a health-care provider (HCP). Simple assessments of value can be made by estimating such unknowns, but the levels of uncertainty may mean that their operational value for investment decisions is unclear. However, many decisions taken at the concept stage are reversible and will be reconsidered later before the product is brought to market. This flexibility can be exploited to enhance early-stage valuations. To develop a framework for valuing a new medical device at the concept stage that balances benefit to the HCP against commercial costs. This is done within a simplified stage-gated model of the development cycle for new products. The approach is intended to complement existing proposals for the evaluation of the commercial headroom available to new medical products. A model based on two decision gates can lead to lower bounds (underestimates) for product value that can serve to support a decision to develop the product. Quantifiable uncertainty that can be resolved before the device is brought to market will generally enhance early-stage valuations of the device, and this remains true even when some components of uncertainty cannot be fully described. Clinical trials and other evidence-gathering activities undertaken as part of the development process can contribute to early-stage estimates of value.

Do forest soil microbes have the potential to resist plant invasion? A case study in Dinghushan Biosphere Reserve (South China)

NASA Astrophysics Data System (ADS)

Chen, Bao-Ming; Li, Song; Liao, Hui-Xuan; Peng, Shao-Lin

2017-05-01

Successful invaders must overcome biotic resistance, which is defined as the reduction in invasion success caused by the resident community. Soil microbes are an important source of community resistance to plant invasions, and understanding their role in this process requires urgent investigation. Therefore, three forest communities along successional stages and four exotic invasive plant species were selected to test the role of soil microbes of three forest communities in resisting the exotic invasive plant. Our results showed that soil microbes from a monsoon evergreen broadleaf forest (MEBF) (late-successional stage) had the greatest resistance to the invasive plants. Only the invasive species Ipomoea triloba was not sensitive to the three successional forest soils. Mycorrhizal fungi in early successional forest Pinus massonina forest (PMF) or mid-successional forest pine-broadleaf mixed forest (PBMF) soil promoted the growth of Mikania micrantha and Eupatorium catarium, but mycorrhizal fungi in MEBF soil had no significant effects on their growth. Pathogens plus other non-mycorrhizal microbes in MEBF soil inhibited the growth of M. micrantha and E. catarium significantly, and only inhibited root growth of E. catarium when compared with those with mycorrhizal fungi addition. The study suggest that soil mycorrhizal fungi of early-mid-successional forests benefit invasive species M. micrantha and E. catarium, while soil pathogens of late-successional forest may play an important role in resisting M. micrantha and E. catarium. The benefit and resistance of the soil microbes are dependent on invasive species and related to forest succession. The study gives a possible clue to control invasive plants by regulating soil microbes of forest community to resist plant invasion.

SEOM clinical guidelines in early-stage breast cancer 2015.

PubMed

Garcia-Saenz, J A; Bermejo, B; Estevez, L G; Palomo, A G; Gonzalez-Farre, X; Margeli, M; Pernas, S; Servitja, S; Rodriguez, C A; Ciruelos, E

2015-12-01

Breast cancer is a major public health problem. Despite remarkable advances in early diagnosis and treatment, one in three women may have metastases since diagnosis. Better understanding of prognostic and predictive factors allows us to select the most appropriate adjuvant therapy in each patient. In these guidelines, we summarize current evidence for the medical management of early-stage breast cancer.

Presence of early stage cancer does not impair the early protein metabolic response to major surgery

PubMed Central

Klimberg, V. Suzanne; Allasia, Arianna; Deutz, Nicolaas EP

2017-01-01

Abstract Background Combined bilateral mastectomy and reconstruction is a common major surgical procedure in women with breast cancer and in those with a family history of breast cancer. As this large surgical procedure induces muscle protein loss, a preserved anabolic response to nutrition is warranted for optimal recovery. It is unclear whether the presence of early stage cancer negatively affects the protein metabolic response to major surgery as this would mandate perioperative nutritional support. Methods In nine women with early stage (Stage II) breast malignancy and nine healthy women with a genetic predisposition to breast cancer undergoing the same large surgical procedure, we examined whether surgery influences the catabolic response to overnight fasting and the anabolic response to nutrition differently. Prior to and within 24 h after combined bilateral mastectomy and reconstruction surgery, whole body protein synthesis and breakdown rates were assessed after overnight fasting and after meal intake by stable isotope methodology to enable the calculation of net protein catabolism in the post‐absorptive state and net protein anabolic response to a meal. Results Major surgery resulted in an up‐regulation of post‐absorptive protein synthesis and breakdown rates (P < 0.001) and lower net protein catabolism (P < 0.05) and was associated with insulin resistance and increased systemic inflammation (P < 0.01). Net anabolic response to the meal was reduced after surgery (P < 0.05) but higher in cancer (P < 0.05) indicative of a more preserved meal efficiency. The significant relationship between net protein anabolism and the amount of amino acids available in the circulation (R 2 = 0.85, P < 0.001) was independent of the presence of non‐cachectic early stage breast cancer or surgery. Conclusions The presence of early stage breast cancer does not enhance the normal catabolic response to major surgery or further attenuates the

Presence of early stage cancer does not impair the early protein metabolic response to major surgery.

PubMed

Engelen, Mariëlle P K J; Klimberg, V Suzanne; Allasia, Arianna; Deutz, Nicolaas Ep

2017-06-01

Combined bilateral mastectomy and reconstruction is a common major surgical procedure in women with breast cancer and in those with a family history of breast cancer. As this large surgical procedure induces muscle protein loss, a preserved anabolic response to nutrition is warranted for optimal recovery. It is unclear whether the presence of early stage cancer negatively affects the protein metabolic response to major surgery as this would mandate perioperative nutritional support. In nine women with early stage (Stage II) breast malignancy and nine healthy women with a genetic predisposition to breast cancer undergoing the same large surgical procedure, we examined whether surgery influences the catabolic response to overnight fasting and the anabolic response to nutrition differently. Prior to and within 24 h after combined bilateral mastectomy and reconstruction surgery, whole body protein synthesis and breakdown rates were assessed after overnight fasting and after meal intake by stable isotope methodology to enable the calculation of net protein catabolism in the post-absorptive state and net protein anabolic response to a meal. Major surgery resulted in an up-regulation of post-absorptive protein synthesis and breakdown rates (P < 0.001) and lower net protein catabolism (P < 0.05) and was associated with insulin resistance and increased systemic inflammation (P < 0.01). Net anabolic response to the meal was reduced after surgery (P < 0.05) but higher in cancer (P < 0.05) indicative of a more preserved meal efficiency. The significant relationship between net protein anabolism and the amount of amino acids available in the circulation (R 2  = 0.85, P < 0.001) was independent of the presence of non-cachectic early stage breast cancer or surgery. The presence of early stage breast cancer does not enhance the normal catabolic response to major surgery or further attenuates the anabolic response to meal intake within 24 h after

Determining the K coefficient to leaf area index estimations in a tropical dry forest

NASA Astrophysics Data System (ADS)

Magalhães, Sarah Freitas; Calvo-Rodriguez, Sofia; do Espírito Santo, Mário Marcos; Sánchez Azofeifa, Gerardo Arturo

2018-03-01

Vegetation indices are useful tools to remotely estimate several important parameters related to ecosystem functioning. However, improving and validating estimations for a wide range of vegetation types are necessary. In this study, we provide a methodology for the estimation of the leaf area index (LAI) in a tropical dry forest (TDF) using the light diffusion through the canopy as a function of the successional stage. For this purpose, we estimated the K coefficient, a parameter that relates the normalized difference vegetation index (NDVI) to LAI, based on photosynthetically active radiation (PAR) and solar radiation. The study was conducted in the Mata Seca State Park, in southeastern Brazil, from 2012 to 2013. We defined four successional stages (very early, early, intermediate, and late) and established one optical phenology tower at one plot of 20 × 20 m per stage. Towers measured the incoming and reflected solar radiation and PAR for NDVI calculation. For each plot, we established 24 points for LAI sampling through hemispherical photographs. Because leaf cover is highly seasonal in TDFs, we determined ΔK (leaf growth phase) and K max (leaf maturity phase). We detected a strong correlation between NDVI and LAI, which is necessary for a reliable determination of the K coefficient. Both NDVI and LAI varied significantly between successional stages, indicating sensitivity to structural changes in forest regeneration. Furthermore, the K values differed between successional stages and correlated significantly with other environmental variables such as air temperature and humidity, fraction of absorbed PAR, and soil moisture. Thus, we established a model based on spectral properties of the vegetation coupled with biophysical characteristics in a TDF that makes possible to estimate LAI from NDVI values. The application of the K coefficient can improve remote estimations of forest primary productivity and gases and energy exchanges between vegetation and atmosphere

Development of bacterial communities in biological soil crusts along a revegetation chronosequence in the Tengger Desert, northwest China

NASA Astrophysics Data System (ADS)

Liu, Lichao; Liu, Yubing; Zhang, Peng; Song, Guang; Hui, Rong; Wang, Zengru; Wang, Jin

2017-08-01

Knowledge of structure and function of microbial communities in different successional stages of biological soil crusts (BSCs) is still scarce for desert areas. In this study, Illumina MiSeq sequencing was used to assess the compositional changes of bacterial communities in different ages of BSCs in the revegetation of Shapotou in the Tengger Desert. The most dominant phyla of bacterial communities shifted with the changed types of BSCs in the successional stages, from Firmicutes in mobile sand and physical crusts to Actinobacteria and Proteobacteria in BSCs, and the most dominant genera shifted from Bacillus, Enterococcus and Lactococcus to RB41_norank and JG34-KF-361_norank. Alpha diversity and quantitative real-time polymerase chain reaction (PCR) analysis indicated that bacterial richness and abundance reached their highest levels after 15 years of BSC development. Redundancy analysis showed that silt + clay content and total K were the prime determinants of the bacterial communities of BSCs. The results suggested that bacterial communities of BSCs recovered quickly with the improved soil physicochemical properties in the early stages of BSC succession. Changes in the bacterial community structure may be an important indicator in the biogeochemical cycling and nutrient storage in early successional stages of BSCs in desert ecosystems.

Effects of genistein on early-stage cutaneous wound healing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Eunkyo; Lee, Seung Min; Jung, In-Kyung

2011-07-08

Highlights: {yields} We examine the effect of genistein on cutaneous wound healing. {yields} Genistein enhanced wound closure during the early stage of wound healing. {yields} These genistein effects on wound closure were induced by reduction of oxidative stress through increasing antioxidant capacity and modulation of pro-inflammatory cytokine expression. -- Abstract: Wound healing occurs in three sequential phases: hemostasis and inflammation, proliferation, and remodeling. Inflammation, the earliest phase, is considered a critical period for wound healing because immune cells remove damaged tissues, foreign debris, and remaining dead tissue. Wound healing would be delayed without inflammation, and this phase is affected bymore » antioxidation capacity. Therefore, we hypothesized that genistein, which has an antioxidant effect, might modulate the wound healing process by altering the inflammatory response. After three days of acclimation, mice were divided into three groups: control, 0.025% genistein, and 0.1% genistein. After two weeks of an experimental diet, skin wounds were induced. Wounded skin areas were imaged, and the healing rate calculated. To measure lipid peroxidation, antioxidant enzyme expression and activity, and pro-inflammatory cytokine expression, skin and liver tissues were harvested at 12, 24, 48, and 72 h. Genistein did not affect body weight. The rate of wound closure in mice fed genistein was significantly faster than in the control group during the early stage of wound healing, especially in first three days. Cu, Zn-SOD and Mn-SOD expression in wound skin tissue in the 0.1% genistein group was lower than in the control group. However, CAT expression did not differ among groups. We also found that genistein modulated NF-{kappa}B and TNF-{alpha} expression during the early stage of wound healing. The genistein group had significantly lower hepatic lipid peroxidation and higher SOD, CAT, and GPx activities than the control group. These

CARBON AND NITROGEN POOLS IN OREGON CASCADES FORESTS OVER A SUCCESSIONAL GRADIENT

EPA Science Inventory

In a study to examine impacts of successional and disturbance history on N export from 20 headwater stream systems in the west central Cascades of Oregon, a region of low anthropogenic N inputs, watersheds of differing ages showed a number of significant difference in nutrient ...

Folding of Polymer Chains in Early Stage of Crystallization

NASA Astrophysics Data System (ADS)

Yuan, Shichen; Miyoshi, Toshikazu

Understanding the structural formation of long polymer chains in the early stage of crystallization is one of the long-standing problems in polymer science. Using solid state NMR, we investigated chain trajectory of isotactic polypropylene in the mesomorphic nano-domains formed via rapid and deep quenching. Comparison of experimental and simulated 13C-13C Double Quantum (DQ) buildup curves demonstrated that instead of random re-entry models and solidification models, individual chains in the mesomorphic form iPP adopt adjacent reentry sequences with an average folding number of = 3-4 (assuming an adjacent re-entry fraction of of 100%) during mesomorphic formation process via nucleation and growth in the early stage. This work was financially supported by the National Science Foundation (Grant DMR-1105829 and 1408855) and startup funds from the UA.

Is knowledge translation adequate? A quality assurance study of staging investigations in early stage breast cancer patients.

PubMed

Han, Dolly; Hogeveen, Sophie; Sweet Goldstein, Miriam; George, Ralph; Brezden-Masley, Christine; Hoch, Jeffrey; Haq, Rashida; Simmons, Christine E

2012-02-01

After primary surgery, patients diagnosed with early stage breast cancer undergo radiological investigations based on pathologic stage of disease to rule out distant metastases. Published guidelines can aid clinicians in determining which tests are appropriate based on stage of disease. We wished to assess the consistency of radiological staging in an academic community oncology setting with standard guidelines and to determine the overall impact of non-adherence to these guidelines. A retrospective cohort study was conducted for new breast cancer patients seen at a single institution between January 2009 and April 2010. Patients were included if initial diagnosis and primary surgery was at this institution. Pathologic stage and radiological tests completed were recorded. A literature review was performed and the results were compared with those from this study to determine overall adherence rates. Subsequently, a cost analysis was performed to determine the financial impact at this centre. 231 patients met eligibility criteria for inclusion in this study. A large proportion of patients were over-staged with 129 patients (55%) undergoing unnecessary investigations according to guidelines. Specifically, 59% of stage I patients and 58% of stage II patients were over-investigated. Distant metastases at the time of diagnosis were found in three patients, all of whom had stage III disease (1.3%). The literature reviewed revealed similar non-adherence rates in other centres. The estimated cost of such non-adherence is in the range of $78 (CDN) per new early stage breast cancer patient seen at this centre. This oncology centre has a low adherence to practice guidelines for staging investigations in breast cancer patients, with 55% of patients undergoing unnecessary tests. Very few patients had metastases at diagnosis, and all had pathological stage III disease. Efforts may need to focus on improving knowledge translation across clinical oncology settings to increase

Successional convergence in experimentally disturbed intertidal communities.

PubMed

Martins, Gustavo M; Arenas, Francisco; Tuya, Fernando; Ramírez, Rubén; Neto, Ana I; Jenkins, Stuart R

2018-02-01

Determining the causes of variation in community assembly is a central question in ecology. Analysis of β-diversity can provide insight by relating the extent of regional to local variation in diversity, allowing inference of the relative importance of deterministic versus stochastic processes. We investigated the effects of disturbance timing on community assembly at three distinct regions with varying environmental conditions: Northern Portugal, Azores and Canaries. On the lower rocky intertidal, quadrats were experimentally cleared of biota at three distinct times of the year and community assembly followed for 1 year. Similar levels of α- and γ-diversity were found in all regions, which remained constant throughout succession. When Jaccard (incidence-based) and Bray-Curtis (abundance-based) metrics were used, β-diversity (the mean dissimilarity among plots cleared at the different times) was larger during early stages of community assembly but decreased over time. The adaptation of the Raup-Crick's metric, which accounts for changes in species richness, showed that the structure of assemblages disturbed at different times of the year was similar to the null model of random community assembly during early stages of succession but became more similar than expected by chance. This pattern was observed in all regions despite differences in the regional species pool, suggesting that priority effects are likely weak and deterministic processes determine community structure despite stochasticity during early stages of community assembly.

Integrating a rangeland health assessment with successional management: A synergistic approach to EBIPM

USDA-ARS?s Scientific Manuscript database

Qualitative Rangeland Health Assessments are extremely useful because they provide a relative indication of resource problems on rangelands. Additionally, theSuccessional Management framework identifies three primary causes of plantcommunity change, ecological processes, and factors that modify thes...

Radiation therapy in early-stage invasive breast cancer.

PubMed

Lin, Ray; Tripuraneni, Prabhakar

2011-06-01

The treatment of breast cancer involves a multi-disciplinary approach with radiation therapy playing a key role. Breast-conserving surgery has been an option for women with early-stage breast cancer for over two decades now. Multiple randomized trials now have demonstrated the efficacy of breast-conserving surgery followed by radiation therapy. With the advancements in breast imaging and the successful campaign for early detection of breast cancer, more women today are found to have early-stage small breast cancers. Patient factors (breast size, tumor location, history of prior radiation therapy, preexisting conditions such as collagen vascular disease, age, having prosthetically augmented breasts), pathological factors (margin status, tumor size, presence of extensive intraductal component requiring multiple surgical excisions), as well as patient preference are all taken into consideration prior to surgical management of breast cancer. Whole-breast fractionated radiation therapy between 5 and 7 weeks is considered as the standard of care treatment following breast-conserving surgery. However, new radiation treatment strategies have been developed in recent years to provide alternatives to the conventional 5-7 week whole-breast radiation therapy for some patients. Accelerated partial breast radiation therapy (APBI) was introduced because the frequency of breast recurrences outside of the surgical cavity has been shown to be low. This technique allows treatments to be delivered quicker (usually 1 week, twice daily) to a limited volume. Often times, this treatment involves the use of a brachytherapy applicator to be placed into the surgical cavity following breast-conserving surgery. Accelerated hypofractionated whole-breast irradiation may be another faster way to deliver radiation therapy following breast-conserving surgery. This journal article reviews the role of radiation therapy in women with early-stage breast cancer addressing patient selection in breast

Liquid biopsy for early stage lung cancer.

PubMed

Liang, Wenhua; Zhao, Yi; Huang, Weizhe; Liang, Hengrui; Zeng, Haikang; He, Jianxing

2018-04-01

Liquid biopsy, which analyzes biological fluids especially blood specimen to detect and quantify circulating cancer biomarkers, have been rapidly introduced and represents a promising potency in clinical practice of lung cancer diagnosis and prognosis. Unlike conventional tissue biopsy, liquid biopsy is non-invasive, safe, simple in procedure, and is not influenced by manipulators' skills. Notably, some circulating cancer biomarkers are already detectable in disease with low-burden, making liquid biopsy feasible in detecting early stage lung cancer. In this review, we described a landscape of different liquid biopsy methods by highlighting the rationale and advantages, accessing the value of various circulating biomarkers and discussing their possible future development in the detection of early lung cancer.

Biodiversity and functional regeneration during secondary succession in a tropical dry forest: from microorganisms to mammals

NASA Astrophysics Data System (ADS)

do Espírito Santo, M. M.; Neves, F. S.; Valério, H. M.; Leite, L. O.; Falcão, L. A.; Borges, M.; Beirão, M.; Reis, R., Jr.; Berbara, R.; Nunes, Y. R.; Silva, A.; Silva, L. F.; Siqueira, P. R.

2015-12-01

In this study, we aimed to determine the changes on soil traits, forest structure and species richness and composition of multiple groups of organisms along secondary succession in a tropical dry forest (TDF) in southeastern Brazil. We defined three successional stages based in forest vertical and horizontal structure and age: early (18-25 years), intermediate (50-60 years) and late (no records of clearing). Five plots of 50 x 20 m were established per stage, and the following groups were sampled using specific techniques: rhizobacteria, mycorrhiza, trees and lianas, butterflies, ants, dung beetles, mosquitoes (Culicidae), birds and bats. We also determined soil chemical and physical characteristics and forest structure (tree height, density and basal area). Soil fertility increased along the successional gradient, and the same pattern was observed for all the forest structure variables. However, species richness and composition showed mixed results depending on the organism group. Three groups usually considered as good bioindicators of habitat quality did not differ in species richness and composition between stages: butterflies, ants and dung beetles. On the other hand, rizhobacteria and mycorrhiza differed both in species richness and composition between stages and may be more sensitive to changes in environmental conditions in TDFs. The other five groups differed either in species richness or composition between one or two pairs of successional stages. Although changes in abiotic conditions and forest structure match the predictions of classical successional models, the response of each group of organism is idiosyncratic in terms of diversity and ecological function, as a consequence of specific resource requirements and life-history traits. In general, diversity increased and functional groups changed mostly from early to intermediate-late stages, strengthening the importance of secondary forests to the maintenance of ecosystem integrity of TDFs.

Demography of Symbiotic Nitrogen-Fixing Trees Explains Their Rarity and Successional Decline in Temperate Forests in the United States.

PubMed

Liao, Wenying; Menge, Duncan N L

2016-01-01

Symbiotic nitrogen (N) fixation is the major N input to many ecosystems. Although temperate forests are commonly N limited, symbiotic N-fixing trees ("N fixers") are rare and decline in abundance as succession proceeds-a challenging paradox that remains unexplained. Understanding demographic processes that underlie N fixers' rarity and successional decline would provide a proximate answer to the paradox. Do N fixers grow slower, die more frequently, or recruit less in temperate forests? We quantified demographic rates of N-fixing and non-fixing trees across succession using U.S. forest inventory data. We used an individual-based model to evaluate the relative contribution of each demographic process to community dynamics. Compared to non-fixers, N fixers had lower growth rates, higher mortality rates, and lower recruitment rates throughout succession. The mortality effect contributed more than the growth effect to N fixers' successional decline. Canopy and understory N fixers experienced these demographic disadvantages, indicating that factors in addition to light limitation likely contribute to N fixers' successional decline. We show that the rarity and successional decline of N-fixing trees in temperate forests is due more to their survival disadvantage than their growth disadvantage, and a recruitment disadvantage might also play a large role.

Demography of Symbiotic Nitrogen-Fixing Trees Explains Their Rarity and Successional Decline in Temperate Forests in the United States

PubMed Central

Liao, Wenying; Menge, Duncan N. L.

2016-01-01

Symbiotic nitrogen (N) fixation is the major N input to many ecosystems. Although temperate forests are commonly N limited, symbiotic N-fixing trees (“N fixers”) are rare and decline in abundance as succession proceeds–a challenging paradox that remains unexplained. Understanding demographic processes that underlie N fixers’ rarity and successional decline would provide a proximate answer to the paradox. Do N fixers grow slower, die more frequently, or recruit less in temperate forests? We quantified demographic rates of N-fixing and non-fixing trees across succession using U.S. forest inventory data. We used an individual-based model to evaluate the relative contribution of each demographic process to community dynamics. Compared to non-fixers, N fixers had lower growth rates, higher mortality rates, and lower recruitment rates throughout succession. The mortality effect contributed more than the growth effect to N fixers’ successional decline. Canopy and understory N fixers experienced these demographic disadvantages, indicating that factors in addition to light limitation likely contribute to N fixers’ successional decline. We show that the rarity and successional decline of N-fixing trees in temperate forests is due more to their survival disadvantage than their growth disadvantage, and a recruitment disadvantage might also play a large role. PMID:27780268

Development of an early-stage toll revenue estimation model.

DOT National Transportation Integrated Search

2012-05-01

With agencies and states increasingly considering tolls as a means to finance transportation infrastructure, : there is an increasing need to quickly assess the feasibility of potential tolling projects. In the early stages : of a project when an age...

Confidence interval estimation of the difference between two sensitivities to the early disease stage.

PubMed

Dong, Tuochuan; Kang, Le; Hutson, Alan; Xiong, Chengjie; Tian, Lili

2014-03-01

Although most of the statistical methods for diagnostic studies focus on disease processes with binary disease status, many diseases can be naturally classified into three ordinal diagnostic categories, that is normal, early stage, and fully diseased. For such diseases, the volume under the ROC surface (VUS) is the most commonly used index of diagnostic accuracy. Because the early disease stage is most likely the optimal time window for therapeutic intervention, the sensitivity to the early diseased stage has been suggested as another diagnostic measure. For the purpose of comparing the diagnostic abilities on early disease detection between two markers, it is of interest to estimate the confidence interval of the difference between sensitivities to the early diseased stage. In this paper, we present both parametric and non-parametric methods for this purpose. An extensive simulation study is carried out for a variety of settings for the purpose of evaluating and comparing the performance of the proposed methods. A real example of Alzheimer's disease (AD) is analyzed using the proposed approaches. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Efficient embryonic culture method for the Japanese striped snake, Elaphe quadrivirgata, and its early developmental stages.

PubMed

Matsubara, Yoshiyuki; Sakai, Atsushi; Kuroiwa, Atsushi; Suzuki, Takayuki

2014-10-01

The morphogenesis of snake embryos is an elusive yet fascinating research target for developmental biologists. However, few data exist on development of early snake embryo due to limited availability of pregnant snakes, and the need to harvest early stage embryos directly from pregnant snakes before oviposition without knowing the date of fertilization. We established an ex vivo culture method for early snake embryos using the Japanese striped snake, Elaphe quadrivirgata. This method, which we named "sausage-style (SS) culture", allows us to harvest snake embryos at specific stages for each experiment. Using this SS culture system, we calculated somite formation rate at early stages before oviposition. The average somite formation rate between 6/7 and 12/13 somite stages was 145.9 min, between 60/70 and 80/91 somite stages 42.4 min, and between 113-115 and 126/127 somite stages 71 min. Thus, somite formation rate that we observed during early snake embryogenesis was changed over time. We also describe a developmental staging series for E. quadrivirgata. This is the first report of a developmental series of early snake embryogenesis prior to oviposition by full-color images with high-resolution. We propose that the SS culture system is an easy method for treating early snake embryos ex vivo. © 2014 The Authors Development, Growth & Differentiation © 2014 Japanese Society of Developmental Biologists.

Shrub-Steppe Early Succession Following Juniper Cutting and Prescribed Fire

NASA Astrophysics Data System (ADS)

Bates, Jonathan D.; Davies, Kirk W.; Sharp, Robert N.

2011-03-01

Pinus- Juniperus L. (Piñon-juniper) woodlands of the western United States have expanded in area nearly 10-fold since the late 1800's. Juniperus occidentalis ssp. occidentalis Hook. (western juniper) dominance in sagebrush steppe has several negative consequences, including reductions in herbaceous production and diversity, decreased wildlife habitat, and higher erosion and runoff potentials. Prescribed fire and mechanical tree removal are the main methods used to control J. occidentalis and restore sagebrush steppe. However, mature woodlands become difficult to prescribe burn because of the lack of understory fuels. We evaluated partial cutting of the woodlands (cutting 25-50% of the trees) to increase surface fuels, followed by prescribed fire treatments in late successional J. occidentalis woodlands of southwest Idaho to assess understory recovery. The study was conducted in two different plant associations and evaluated what percentage of the woodland required preparatory cutting to eliminate remaining J. occidentalis by prescribed fire, determined the impacts of fire to understory species, and examined early post-fire successional dynamics. The study demonstrated that late successional J. occidentalis woodlands can be burned after pre-cutting only a portion of the trees. Early succession in the cut-and-burn treatments were dominated by native annual and perennial forbs, in part due to high mortality of perennial bunchgrasses. By the third year after fire the number of establishing perennial grass seedlings indicated that both associations would achieve full herbaceous recovery. Cutting-prescribed fire combinations are an effective means for controlling encroaching late successional J. occidentalis and restoring herbaceous plant communities. However, land managers should recognize that there are potential problems associated with cutting-prescribed fire applications when invasive weeds are present.

Shrub-steppe early succession following juniper cutting and prescribed fire.

PubMed

Bates, Jonathan D; Davies, Kirk W; Sharp, Robert N

2011-03-01

Pinus-Juniperus L. (Piñon-juniper) woodlands of the western United States have expanded in area nearly 10-fold since the late 1800's. Juniperus occidentalis ssp. occidentalis Hook. (western juniper) dominance in sagebrush steppe has several negative consequences, including reductions in herbaceous production and diversity, decreased wildlife habitat, and higher erosion and runoff potentials. Prescribed fire and mechanical tree removal are the main methods used to control J. occidentalis and restore sagebrush steppe. However, mature woodlands become difficult to prescribe burn because of the lack of understory fuels. We evaluated partial cutting of the woodlands (cutting 25-50% of the trees) to increase surface fuels, followed by prescribed fire treatments in late successional J. occidentalis woodlands of southwest Idaho to assess understory recovery. The study was conducted in two different plant associations and evaluated what percentage of the woodland required preparatory cutting to eliminate remaining J. occidentalis by prescribed fire, determined the impacts of fire to understory species, and examined early post-fire successional dynamics. The study demonstrated that late successional J. occidentalis woodlands can be burned after pre-cutting only a portion of the trees. Early succession in the cut-and-burn treatments were dominated by native annual and perennial forbs, in part due to high mortality of perennial bunchgrasses. By the third year after fire the number of establishing perennial grass seedlings indicated that both associations would achieve full herbaceous recovery. Cutting-prescribed fire combinations are an effective means for controlling encroaching late successional J. occidentalis and restoring herbaceous plant communities. However, land managers should recognize that there are potential problems associated with cutting-prescribed fire applications when invasive weeds are present.

Signatures of unfolding in the early stages of protein denaturation

NASA Astrophysics Data System (ADS)

Gray, Harry B.; Winkler, Jay R.; Kozak, John J.

2012-04-01

A comparative study of the early stages of unfolding of five proteins: cyt c, c-b 562, cyt c‧, azurin, and lysozyme is reported. From crystallographic data, helical regions and intervening non-helical (or 'turning') regions are identified in each. Exploiting a previously introduced geometrical model, the paper describes quantitatively the stepwise extension of a polypeptide chain subject to the geometrical constraint that the spatial relationship among the residues of each triplet is fixed by native-state crystallographic data. Despite differences among the above-cited proteins, remarkable universality of behavior is found in the early stages of unfolding. At the very earliest stages, internal residues in each helical region have a common unfolding history; the terminal residues, however, are extraordinarily sensitive to structural perturbations. Residues in non-helical sections of the polypeptide unfold after residues in the internal helical regions, but with increasing steric perturbation playing a dominant role in advancing denaturation.

Occurrence of lymph node metastasis in early-stage parotid gland cancer.

PubMed

Stenner, Markus; Molls, Christoph; Luers, Jan C; Beutner, Dirk; Klussmann, Jens P; Huettenbrink, Karl-Bernd

2012-02-01

Lymph node metastasis is one of the most important factors in therapy and prognosis for patients with parotid gland cancer. Nevertheless, the extent of the primary tumor resection and the necessity of a neck dissection still is a common issue. Since little is known about lymph node metastasis in early-stage parotid gland cancer, the purpose of the present study was to evaluate the occurrence of lymph node metastases in T1 and T2 carcinomas and its impact on local control and survival. We retrospectively analyzed 70 patients with early-stage (T1 and T2) primary parotid gland cancer. All patients were treated with parotidectomy and an ipsilateral neck dissection from 1987 to 2009. Clinicopathological and survival parameters were calculated. The median follow-up time was 51.7 months. A positive pathological lymph node stage (pN+) was found in 21.4% of patients with a significant correlation to the clinical lymph node stage (cN) (p = 0.061). There were no differences in the clinical and histopathological data between pN- and pN+ patients. In 73.3% of pN+ patients, the metastases were located intraparotideal. The incidence of occult metastases (pN+/cN-) was 17.2%. Of all patients with occult metastases, 30.0% had extraparotideal lymphatic spread. A positive lymph node stage significantly indicated a poorer 5-year overall as well as 5-year disease-free survival rate compared to pN- patients (p = 0.048; p = 0.011). We propose total parotidectomy in combination with at least a level II-III selective neck dissection in any case of early-stage parotid gland cancer.

Predictable communities of soil bacteria in relation to nutrient concentration and successional stage in a laboratory culture experiment.

PubMed

Song, Woojin; Kim, Mincheol; Tripathi, Binu M; Kim, Hyoki; Adams, Jonathan M

2016-06-01

It is difficult to understand the processes that structure immensely complex bacterial communities in the soil environment, necessitating a simplifying experimental approach. Here, we set up a microcosm culturing experiment with soil bacteria, at a range of nutrient concentrations, and compared these over time to understand the relationship between soil bacterial community structure and time/nutrient concentration. DNA from each replicate was analysed using HiSeq2000 Illumina sequencing of the 16S rRNA gene. We found that each nutrient treatment, and each time point during the experiment, produces characteristic bacterial communities that occur predictably between replicates. It is clear that within the context of this experiment, many soil bacteria have distinct niches from one another, in terms of both nutrient concentration, and successional time point since a resource first became available. This fine niche differentiation may in part help to explain the coexistence of a diversity of bacteria in soils. In this experiment, we show that the unimodal relationship between nutrient concentration/time and species diversity often reported in communities of larger organisms is also evident in microbial communities. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

Primary Surgery vs Radiotherapy for Early Stage Oral Cavity Cancer.

PubMed

Ellis, Mark A; Graboyes, Evan M; Wahlquist, Amy E; Neskey, David M; Kaczmar, John M; Schopper, Heather K; Sharma, Anand K; Morgan, Patrick F; Nguyen, Shaun A; Day, Terry A

2018-04-01

Objective The goal of this study is to determine the effect of primary surgery vs radiotherapy (RT) on overall survival (OS) in patients with early stage oral cavity squamous cell carcinoma (OCSCC). In addition, this study attempts to identify factors associated with receiving primary RT. Study Design Retrospective cohort study. Setting National Cancer Database (NCDB, 2004-2013). Subjects and Methods Reviewing the NCDB from 2004 to 2013, patients with early stage I to II OCSCC were identified. Kaplan-Meier estimates of survival, Cox regression analysis, and propensity score matching were used to examine differences in OS between primary surgery and primary RT. Multivariable logistic regression analysis was performed to identify factors associated with primary RT. Results Of the 20,779 patients included in the study, 95.4% (19,823 patients) underwent primary surgery and 4.6% (956 patients) underwent primary RT. After adjusting for covariates, primary RT was associated with an increased risk of mortality (adjusted hazard ratio [aHR], 1.97; 99% confidence interval [CI], 1.74-2.22). On multivariable analysis, factors associated with primary RT included age ≥70 years, black race, Medicaid or Medicare insurance, no insurance, oral cavity subsite other than tongue, clinical stage II disease, low-volume treatment facilities, and earlier treatment year. Conclusion Primary RT for early stage OCSCC is associated with increased mortality. Approximately 5% of patients receive primary RT; however, this percentage is decreasing. Patients at highest risk for receiving primary RT include those who are elderly, black, with public insurance, and treated at low-volume facilities.

[Clinical Advanced in Early-stage ALK-positive Non-small Cell Lung Cancer Patients].

PubMed

Gao, Qiongqiong; Jiang, Xiangli; Huang, Chun

2017-02-20

Lung cancer is the leading cause of cancer death in China. Non-small cell lung cancer (NSCLC) accounts for 85% of lung cancer cases, with the majority of the cases diagnosed at the advanced stage. Molecular targeted therapy is becoming the focus attention for advanced NSCLC. Echinoderm microtubule-associated protein-like 4 gene and the anaplastic lymphoma kinase gene (EML4-ALK) is among the most common molecular targets of NSCLC; its specific small-molecule tyrosine kinase inhibitors (TKIs) are approved for use in advanced NSCLC cases of ALK-positive. However, the influence of EML4-ALK fusion gene on the outcome of early-stage NSCLC cases and the necessity of application of TKIs for early-stage ALK-positive NSCLC patients are still uncertain. In this paper, we summarized the progression of testing methods for ALK-positive NSCLC patients as well as clinicopathological implication, outcome, and necessity of application of TKIs for early-stage ALK-positive NSCLC patients.

TOXICITY OF AHR AGONISTS TO FISH EARLY LIFE STAGES

EPA Science Inventory

Fish early life stages are exceptionally sensitive to the lethal toxicity of chemicals that act as arylhydrocarbon receptor (AhR) agonists. Toxicity characterizations based on 2,3,7,8-tetrachlorodibenzo-p-dioxin, generally the most potent AhR agonist, support the toxicity equiva...

Impact of forest seral stage on use of ant communities for rapid assessment of terrestrial ecosystem health.

PubMed

Wike, Lynn D; Martin, F Douglas; Paller, Michael H; Nelson, Eric A

2010-01-01

Bioassessment evaluates ecosystem health by using the responses of a community of organisms that integrate all aspects of the ecosystem. A variety of bioassessment methods have been applied to aquatic ecosystems; however, terrestrial methods are less advanced. The objective of this study was to examine baseline differences in ant communities at different seral stages from clear cut to mature pine plantation as a precursor to developing a broader terrestrial bioassessment protocol. Comparative sampling was conducted at nine sites having four seral stages: clearcut, 5 year recovery, 15 year recovery, and mature stands. Soil and vegetation data were also collected at each site. Ants were identified to genus. Analysis of the ant data indicated that ants respond strongly to habitat changes that accompany ecological succession in managed pine forests, and both individual genera and ant community structure can be used as indicators of successional change. Ants exhibited relatively high diversity in both early and mature seral stages. High ant diversity in mature seral stages was likely related to conditions on the forest floor favoring litter dwelling and cold climate specialists. While ants may be very useful in identifying environmental stress in managed pine forests, adjustments must be made for seral stage when comparing impacted and unimpacted forests.

Population dynamics along a primary succession gradient: do alpine species fit into demographic succession theory?

PubMed Central

Marcante, Silvia; Winkler, Eckart; Erschbamer, Brigitta

2009-01-01

Background and Aims Understanding processes and mechanisms governing changes in plant species along primary successions has been of major importance in ecology. However, to date hardly any studies have focused on the complete life cycle of species along a successional gradient, comparing pioneer, early and late-successional species. In this study it is hypothesized that pioneer species should initially have a population growth rate, λ, greater than one with high fecundity rates, and declining growth rates when they are replaced by late-successional species. Populations of late-successional species should also start, at the mid-successional stage (when pioneer species are declining), with growth rates greater than one and arrive at rates equal to one at the late successional stage, mainly due to higher survival rates that allow these species to persist for a long time. Methods The demography of pioneer- (Saxifraga aizoides), early (Artemisia genipi) and late-successional species (Anthyllis vulneraria ssp. alpicola) was investigated together with that of a ubiquitous species (Poa alpina) along the Rotmoos glacier foreland (2300–2400 m a.s.l., Central Alps, Austria) over 3 years. A matrix modelling approach was used to compare the main demographic parameters. Elasticity values were plotted in a demographic triangle using fecundity, individual growth and survival as vital rates contributing to the population growth rates. Key Results The results largely confirmed the predictions for population growth rates during succession. However, high survival rates of larger adults characterized all species, regardless of where they were growing along the succession. At the pioneer site, high mortality rates of seedlings, plantlets and young individuals were recorded. Fecundity was found to be of minor relevance everywhere, but it was nevertheless sufficient to increase or maintain the population sizes. Conclusions Demographically, all the species over all sites behaved like

13 CFR 107.1181 - Interest reserve requirements for Early Stage SBICs.

Code of Federal Regulations, 2014 CFR

2014-01-01

...) Binding unfunded commitments from your Institutional Investors that cannot be called for any purpose other... 13 Business Credit and Assistance 1 2014-01-01 2014-01-01 false Interest reserve requirements for... Rules for Leverage Issued by An Early Stage Sbic § 107.1181 Interest reserve requirements for Early...

13 CFR 107.1181 - Interest reserve requirements for Early Stage SBICs.

Code of Federal Regulations, 2013 CFR

2013-01-01

...) Binding unfunded commitments from your Institutional Investors that cannot be called for any purpose other... 13 Business Credit and Assistance 1 2013-01-01 2013-01-01 false Interest reserve requirements for... Rules for Leverage Issued by An Early Stage Sbic § 107.1181 Interest reserve requirements for Early...

Subthalamic nucleus deep brain stimulation in early stage Parkinson's disease.

PubMed

Charles, David; Konrad, Peter E; Neimat, Joseph S; Molinari, Anna L; Tramontana, Michael G; Finder, Stuart G; Gill, Chandler E; Bliton, Mark J; Kao, Chris; Phibbs, Fenna T; Hedera, Peter; Salomon, Ronald M; Cannard, Kevin R; Wang, Lily; Song, Yanna; Davis, Thomas L

2014-07-01

Deep brain stimulation (DBS) is an effective and approved therapy for advanced Parkinson's disease (PD), and a recent study suggests efficacy in mid-stage disease. This manuscript reports the results of a pilot trial investigating preliminary safety and tolerability of DBS in early PD. Thirty subjects with idiopathic PD (Hoehn & Yahr Stage II off medication), age 50-75, on medication ≥6 months but ≤4 years, and without motor fluctuations or dyskinesias were randomized to optimal drug therapy (ODT) (n = 15) or DBS + ODT (n = 15). Co-primary endpoints were the time to reach a 4-point worsening from baseline in the UPDRS-III off therapy and the change in levodopa equivalent daily dose from baseline to 24 months. As hypothesized, the mean UPDRS total and part III scores were not significantly different on or off therapy at 24 months. Medication requirements in the DBS + ODT group were lower at all time points with a maximal difference at 18 months. With a few exceptions, differences in neuropsychological functioning were not significant. Two subjects in the DBS + ODT group suffered serious adverse events; remaining adverse events were mild or transient. This study demonstrates that subjects with early stage PD will enroll in and complete trials testing invasive therapies and provides preliminary evidence that DBS is well tolerated in early PD. The results of this trial provide the data necessary to design a large, phase III, double-blind, multicenter trial investigating the safety and efficacy of DBS in early PD. Copyright © 2014 Elsevier Ltd. All rights reserved.

Adjuvant (post-surgery) chemotherapy for early stage epithelial ovarian cancer

PubMed Central

Winter-Roach, Brett A; Kitchener, Henry C; Lawrie, Theresa A

2014-01-01

Background Epithelial ovarian cancer is diagnosed in 4500 women in the UK each year of whom 1700 will ultimately die of their disease.Of all cases 10% to 15% are diagnosed early when there is still a good possibility of cure. The treatment of early stage disease involves surgery to remove disease often followed by chemotherapy. The largest clinical trials of this adjuvant therapy show an overall survival (OS) advantage with adjuvant platinum-based chemotherapy but the precise role of this treatment in subgroups of women with differing prognoses needs to be defined. Objectives To systematically review the evidence for adjuvant chemotherapy in early stage epithelial ovarian cancer to determine firstly whether there is a survival advantage of this treatment over the policy of observation following surgery with chemotherapy reserved for treatment of disease recurrence, and secondly to determine if clinical subgroups of differing prognosis based on histological sub-type, or completeness of surgical staging, have more or less to gain from chemotherapy following initial surgery. Search methods We performed an electronic search using the Cochrane Gynaecological Cancer Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL 2011, Issue 3), MEDLINE (1948 to Aug week 5, 2011) and EMBASE (1980 to week 36, 2011). We developed the search strategy using free-text and medical subject headings (MESH). Selection criteria We selected randomised clinical trials that met the inclusion criteria set out based on the populations, interventions, comparisons and outcome measures. Data collection and analysis Two review authors independently extracted data and assessed trial quality. Disagreements were resolved by discussion with a third review author. We performed random-effects meta-analyses and subgroup analyses. Main results Five randomised controlled trials (RCTs), enrolling 1277 women, with a median follow-up of 46 to 121 months, met the inclusion criteria. Four

Nitrogen use strategies of seedlings from neotropical tree species of distinct successional groups.

PubMed

Oliveira, Halley Caixeta; da Silva, Ligia Maria Inocêncio; de Freitas, Letícia Dias; Debiasi, Tatiane Viegas; Marchiori, Nidia Mara; Aidar, Marcos Pereira Marinho; Bianchini, Edmilson; Pimenta, José Antonio; Stolf-Moreira, Renata

2017-05-01

Few studies have analyzed the strategies of neotropical tree seedlings for absorbing, translocating and assimilating the nitrogen. Here, we compared the nitrogen use strategies of seedlings from six tree species that are native to the Brazilian Atlantic Forest and that belong to different successional groups: Trema micrantha, Heliocarpus popayanensis and Cecropia pachystachya (pioneers), Cariniana estrellensis, Eugenia brasiliensis and Guarea kunthiana (non-pioneers). The effects of cultivating seedlings with nitrate or ammonium on the growth, physiology and nitrogen metabolism were analyzed. Nitrate-grown pioneer species had much higher leaf nitrate reductase activity than non-pioneer ones, but non-pioneer seedlings were also able to use nitrate as a nitrogen source. In addition to this remarkable difference between the groups in the capacity for leaf nitrate assimilation, substantial variations in the nitrogen use strategies were observed within the successional classes. Differently from the other non-pioneers, the canopy species C. estrellensis seemed to assimilate nitrate mainly in the leaves. Morphophysiological analyses showed a gradient of ammonium toxicity response, with E. brasiliensis as the most tolerant species, and T. micrantha and H. popayanensis as the most sensitive ones. Guarea kunthiana showed a relatively low tolerance to ammonium and an unusual high translocation of this cation in the xylem sap. In contrast to the other pioneers, C. pachystachya had a high plasticity in the use of nitrogen sources. Overall, these results suggest that nitrogen use strategies of neotropical tree seedlings were not determined solely by their successional position. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Effects of fire on spotted owl site occupancy in a late-successional forest

USGS Publications Warehouse

Roberts, Susan L.; van Wagtendonk, Jan W.; Miles, A. Keith; Kelt, Douglas A.

2011-01-01

The spotted owl (Strix occidentalis) is a late-successional forest dependent species that is sensitive to forest management practices throughout its range. An increase in the frequency and spatial extent of standreplacing fires in western North America has prompted concern for the persistence of spotted owls and other sensitive late-successional forest associated species. However, there is sparse information on the effects of fire on spotted owls to guide conservation policies. In 2004-2005, we surveyed for California spotted owls during the breeding season at 32 random sites (16 burned, 16 unburned) throughout late-successional montane forest in Yosemite National Park, California. Our burned areas burned at all severities, but predominately involved low to moderate fire severity. Based on an information theoretic approach, spotted owl detection and occupancy rates were similar between burned and unburned sites. Nest and roost site occupancy was best explained by a model that combined total tree basal area (positive effect) with cover by coarse woody debris (negative effect). The density estimates of California spotted owl pairs were similar in burned and unburned forests, and the overall mean density estimate for Yosemite was higher than previously reported for montane forests. Our results indicate that low to moderate severity fires, historically common within montane forests of the Sierra Nevada, California, maintain habitat characteristics essential for spotted owl site occupancy. These results suggest that managed fires that emulate the historic fire regime of these forests may maintain spotted owl habitat and protect this species from the effects of future catastrophic fires.

Using Remote Sensing Technologies to Quantify the Effects of Beech Bark Disease on the Structure, Composition, and Function of a Late-Successional Forest

NASA Astrophysics Data System (ADS)

Stuart-Haëntjens, E. J.; Ricart, R. D.; Fahey, R. T.; Fotis, A. T.; Gough, C. M.

2016-12-01

Ecological theory maintains that as forests age, the rate at which carbon (C) is stored declines because C released through organic matter decomposition offsets declining C sequestration in new vegetative growth. Recent observational studies are challenging this long-held hypothesis, with limited evidence suggesting higher-than-expected rates in late-successional forests could be, counterintuitively, tied to canopy structural changes associated with low intensity tree mortality. As forests age, canopy structural complexity may increase when old trees die and form upper canopy gaps that release subcanopy vegetation. This provides one explanation for observations of sustained high production in old forests. Recent studies have found that this increased structural complexity and resource-use efficiency maintain C storage in mid-successional deciduous forests; whether a similar mechanism extends to late-successional forests is unknown. We will present how a slow, moderate disturbance affects the structure and C sequestration of late-successional forests. Our study site is a forest recently infected by Beech Bark Disease (BBD), which will result in the eventual mortality of American beech trees in this late successional forest in Northern Michigan, at the University of Michigan Biological Station. American Beech, Hemlock, Sugar Maple, and White Pine dominate the landscape, with American Beech making up 30% of the canopy trees on average. At the plot scale American Beech is distributed heterogeneously, comprising 1% to 60% of total plot basal area, making it possible to examine the interplay between disturbance severity, canopy structural change, and primary production resilience in this forest. Within each of the 13 plots, species and stem diameter were collected in 1992, 1994, 2014, and 2016, with future remeasurements planned. We will discuss how ground-based lidar coupled with airborne spectral (IR and RGB) imagery are being used to track canopy BBD

[An unexpected stage of alkalosis in the dynamics of the early posthemorrhagic period].

PubMed

Beliaev, A V

2000-01-01

A study was made on acid-base metabolism in early posthemorrhagic period as exemplified by examination of patients presenting with gastrointestinal hemorrhage. It has been ascertained that hemorrhage is accompanied by a mixed variant of the acid-base state (ABS) deviation, namely metabolic lactate-acidosis and respiratory alkalosis. In the time-related course of posthemorrhagic period such deviations persist in patients with lethal outcome; with the disease running a favourable course the above deviations are found to return to normal quite soon. The development of complications leads to staging in ABC, its stages being as follows: stage I--the initial stage, stage II--persisting metabolic acidosis and respiratory alkalosis, stage III--alkalosis, stage IV--normalization, with stage III of ABS being encouraged by hypocapnia caused by function disorders of the lungs in early posthemorrhagic period, normalization of cell metabolism, increase in the rate of urination as a reflection of the third earlier identified stage of water metabolism, with the H+ excretion in the urine at the previous level. The identified ABS stage III threatens coming trouble, being accompanied by metabolic deviations together with a risk of function disorder of the myocardium.

Disruption of Smad-dependent signaling for growth of GST-P-positive lesions from the early stage in a rat two-stage hepatocarcinogenesis model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ichimura, Ryohei, E-mail: red0828@hotmail.co.j; Mizukami, Sayaka, E-mail: non_sugar_life@hotmail.co.j; Takahashi, Miwa, E-mail: mtakahashi@nihs.go.j

2010-08-01

To clarify the involvement of signaling of transforming growth factor (TGF)-{beta} during the hepatocarcinogenesis, the immunohistochemical distribution of related molecules was analyzed in relation with liver cell lesions expressing glutathione S-transferase placental form (GST-P) during liver tumor promotion by fenbendazole, phenobarbital, piperonyl butoxide, or thioacetamide, using rats. Our study focused on early-stage promotion (6 weeks after starting promotion) and late-stage promotion (57 weeks after starting promotion). With regard to Smad-dependent signaling, cytoplasmic accumulation of phosphorylated Smad (phospho-Smad)-2/3 - identified as Smad3 by later immunoblot analysis - increased in the subpopulation of GST-P{sup +} foci, while Smad4, a nuclear transporter ofmore » Smad2/3, decreased during early-stage promotion. By late-stage promotion, GST-P{sup +} lesions lacking phospho-Smad2/3 had increased in accordance with lesion development from foci to carcinomas, while Smad4 largely disappeared in most proliferative lesions. With regard to Smad-independent mitogen-activated protein kinases, GST-P{sup +} foci that co-expressed phospho-p38 mitogen-activated protein kinase increased during early-stage promotion; however, p38-downstream phospho-activating transcriptional factor (ATF)-2, ATF3, and phospho-c-Myc, were inversely downregulated without relation to promotion. By late-stage promotion, proliferative lesions downregulated phospho-ATF2 and phospho-c-Myc along with lesion development, as with downregulation of phospho-p38 in all lesions. These results suggest that from the early stages, carcinogenic processes were facilitated by disruption of tumor suppressor functions of Smad-dependent signaling, while Smad-independent activation of p38 was an early-stage phenomenon. GST-P{sup -} foci induced by promotion with agonists of peroxisome proliferator-activated receptor-{alpha} did not change Smad expression, suggesting an aberration in the Smad

To Stay or to Go? Narratives of Early-Stage Sociologists about Persisting in Academia

ERIC Educational Resources Information Center

Wöhrer, Veronika

2014-01-01

Based on analyses of life course questionnaires, semi-structured qualitative interviews and focus group interviews carried out with early-stage sociologists over a period of 8 years, this paper presents analyzes of continuity and change in the decisions made by early-stage researchers in regard to their work and careers. The longitudinal approach…

Fertility sparing surgery in early stage epithelial ovarian cancer

PubMed Central

Martinelli, Fabio; Lorusso, Domenica; Haeusler, Edward; Carcangiu, Marialuisa; Raspagliesi, Francesco

2014-01-01

Objective Fertility sparing surgery (FSS) is a strategy often considered in young patients with early epithelial ovarian cancer. We investigated the role and the outcomes of FSS in eEOC patients who underwent comprehensive surgery. Methods From January 2003 to January 2011, 24 patients underwent fertility sparing surgery. Eighteen were one-to-one matched and balanced for stage, histologic type and grading with a group of patients who underwent radical comprehensive staging (n=18). Demographics, surgical procedures, morbidities, pathologic findings, recurrence-rate, pregnancy-rate and correlations with disease-free survival were assessed. Results A total of 36 patients had a complete surgical staging including lymphadenectomy and were therefore analyzed. Seven patients experienced a recurrence: four (22%) in the fertility sparing surgery group and three (16%) in the control group (p=not significant). Sites of recurrence were: residual ovary (two), abdominal wall and peritoneal carcinomatosis in the fertility sparing surgery group; pelvic (two) and abdominal wall in the control group. Recurrences in the fertility sparing surgery group appeared earlier (mean, 10.3 months) than in radical comprehensive staging group (mean, 53.3 months) p<0.001. Disease-free survival were comparable between the two groups (p=0.422). No deaths were reported. All the patients in fertility sparing surgery group recovered a regular period. Thirteen out of 18 (72.2%) attempted to have a pregnancy. Five (38%) achieved a spontaneous pregnancy with a full term delivery. Conclusion Fertility sparing surgery in early epithelial ovarian cancer submitted to a comprehensive surgical staging could be considered safe with oncological results comparable to radical surgery group. PMID:25142621

[Effects of precipitation intensity on soil organic carbon fractions and their distribution under subtropical forests of South China].

PubMed

Chen, Xiao-mei; Liu, Ju-xiu; Deng, Qi; Chu, Guo-wei; Zhou, Guo-yi; Zhang, De-qiang

2010-05-01

From December 2006 to June 2008, a field experiment was conducted to study the effects of natural precipitation, doubled precipitation, and no precipitation on the soil organic carbon fractions and their distribution under a successional series of monsoon evergreen broad-leaf forest, pine and broad-leaf mixed forest, and pine forest in Dinghushan Mountain of Southern China. Different precipitation treatments had no significant effects on the total organic carbon (TOC) concentration in the same soil layer under the same forest type (P > 0.05). In treatment no precipitation, particulate organic carbon (POC) and light fraction organic carbon (LFOC) were mainly accumulated in surface soil layer (0-10 cm); but in treatments natural precipitation and doubled precipitation, the two fractions were infiltrated to deeper soil layers. Under pine forest, soil readily oxidizable organic carbon (ROC) was significantly higher in treatment no precipitation than in treatments natural precipitation and doubled precipitation (P < 0.05). The percentage of soil POC, ROC, and LFOC to soil TOC was much greater under the forests at early successional stage than at climax stage, suggesting that the forest at early successional stage might not be an ideal place for soil organic carbon storage. Precipitation intensity less affected TOC, but had greater effects on the labile components POC, ROC, and LFOC.

Modeling seasonal surface temperature variations in secondary tropical dry forests

NASA Astrophysics Data System (ADS)

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.

[Treatment of non-small cell lung carcinoma in early stages].

PubMed

Meneses, José Carlos; Avila Martínez, Régulo J; Ponce, Santiago; Zuluaga, Mauricio; Bartolomé, Adela; Gámez, Pablo

2013-12-01

Treatment of lung carcinoma is multidisciplinary. There are different therapeutic strategies available, although surgery shows the best results in those patients with lung carcinoma in early stages. Other options such as stereotactic radiation therapy are relegated to patients with small tumors and poor cardiopulmonary reserve or to those who reject surgery. Adjuvant chemotherapy is not justified in patients with stage i of the disease and so double adjuvant chemotherapy should be considered. This adjuvant chemotherapy should be based on cisplatin after surgery in those patients with stages ii and IIIA. Copyright © 2012 AEC. Published by Elsevier Espana. All rights reserved.

Quantifying early-seral forest composition with remote sensing

Treesearch

Rayma A. Cooley; Peter T. Wolter; Brian R. Sturtevant

2016-01-01

Spatially explicit modeling of recovering forest structure within two years following wildfire disturbance has not been attempted, yet such knowledge is critical for determining successional pathways. We used remote sensing and field data, along with digital climate and terrain data, to model and map early-seral aspen structure and vegetation species richness following...

Good daily habits during the early stages of life determine success throughout life.

PubMed

Kohyama, Jun

2016-01-01

This paper assesses hypothesis that sufficient sleep duration and proper circadian rhythms during the early stages of life are indispensable to a successful life. Successful life was defined according to the famous cohort studies of Mischel's and Dunedin. To assess the hypothesis, neuronal elements presumably affecting early daily habits and successful life are reviewed. The effect of sufficient sleep duration and proper circadian rhythms during early stages of life on the development of the prefrontal cortex has been found to be the key issue to verify the hypothesis. Socioeconomic status is found to be another issue to be studied.

Nurses' experiences using a nursing information system: early stage of technology implementation.

PubMed

Lee, Ting-Ting

2007-01-01

Adoption of information technology in nursing practice has become a trend in healthcare. The impact of this technology on users has been widely studied, but little attention has been given to its influence at the beginning stage of implementation. Knowing the barriers to adopting technology could shorten this transition stage and minimize its negative influences. The purpose of this study was to explore nurses' experiences in the early stage of implementing a nursing information system. Focus groups were used to collect data at a medical center in Taiwan. The results showed that nurses had problems with the system's content design, had insufficient training, were concerned about data security, were stressed by added work, and experienced poor interdisciplinary cooperation. To smooth this beginning stage, the author recommends involving nurses early in the system design, providing sufficient training in keyboard entry skills, redesigning workflow, and improving interdisciplinary communication.

Outcomes of laparoscopic fertility-sparing surgery in clinically early-stage epithelial ovarian cancer.

PubMed

Park, Jin-Young; Heo, Eun Jin; Lee, Jeong-Won; Lee, Yoo-Young; Kim, Tae-Joong; Kim, Byoung-Gie; Bae, Duk-Soo

2016-03-01

Fertility-sparing surgery (FSS) is becoming an important technique in the surgical management of young women with early-stage epithelial ovarian cancer (EOC). We retrospectively evaluated the outcome of laparoscopic FSS in presumed clinically early-stage EOC. We retrospectively searched databases of patients who received laparoscopic FSS for EOC between January 1999 and December 2012 at Samsung Medical Center. Women aged ≤40 years were included. The perioperative, oncological, and obstetric outcomes of these patients were evaluated. A total of 18 patients was evaluated. The median age of the patients was 33.5 years (range, 14 to 40 years). The number of patients with clinically stage IA and IC was 6 (33.3%) and 12 (66.7%), respectively. There were 7 (38.9%), 5 (27.8%), 3 (16.7%), and 3 patients (16.7%) with mucinous, endometrioid, clear cell, and serous tumor types, respectively. Complete surgical staging to preserve the uterus and one ovary with adnexa was performed in 4 patients (22.2%). Two out of them were upstaged to The International Federation of Gynecology and Obstetrics stage IIIA1. During the median follow-up of 47.3 months (range, 11.5 to 195.3 months), there were no perioperative or long term surgical complications. Four women (22.2%) conceived after their respective ovarian cancer treatments. Three (16.7%) of them completed full-term delivery and one is expecting a baby. One patient had disease recurrence. No patient died of the disease. FSS in young patients with presumed clinically early-stage EOC is a challenging and cautious procedure. Further studies are urgent to determine the safety and feasibility of laparoscopic FSS in young patients with presumed clinically early-stage EOC.

Outcomes of laparoscopic fertility-sparing surgery in clinically early-stage epithelial ovarian cancer

PubMed Central

Park, Jin-Young; Lee, Yoo-Young; Kim, Tae-Joong; Kim, Byoung-Gie; Bae, Duk-Soo

2016-01-01

Objective Fertility-sparing surgery (FSS) is becoming an important technique in the surgical management of young women with early-stage epithelial ovarian cancer (EOC). We retrospectively evaluated the outcome of laparoscopic FSS in presumed clinically early-stage EOC. Methods We retrospectively searched databases of patients who received laparoscopic FSS for EOC between January 1999 and December 2012 at Samsung Medical Center. Women aged ≤40 years were included. The perioperative, oncological, and obstetric outcomes of these patients were evaluated. Results A total of 18 patients was evaluated. The median age of the patients was 33.5 years (range, 14 to 40 years). The number of patients with clinically stage IA and IC was 6 (33.3%) and 12 (66.7%), respectively. There were 7 (38.9%), 5 (27.8%), 3 (16.7%), and 3 patients (16.7%) with mucinous, endometrioid, clear cell, and serous tumor types, respectively. Complete surgical staging to preserve the uterus and one ovary with adnexa was performed in 4 patients (22.2%). Two out of them were upstaged to The International Federation of Gynecology and Obstetrics stage IIIA1. During the median follow-up of 47.3 months (range, 11.5 to 195.3 months), there were no perioperative or long term surgical complications. Four women (22.2%) conceived after their respective ovarian cancer treatments. Three (16.7%) of them completed full-term delivery and one is expecting a baby. One patient had disease recurrence. No patient died of the disease. Conclusion FSS in young patients with presumed clinically early-stage EOC is a challenging and cautious procedure. Further studies are urgent to determine the safety and feasibility of laparoscopic FSS in young patients with presumed clinically early-stage EOC. PMID:26768783

Anorectal Manometric Dysfunctions in Newly Diagnosed, Early-Stage Parkinson's Disease

PubMed Central

Sung, Hye Young; Kim, Yeong-In; Lee, Kwang-Soo

2012-01-01

Background and Purpose Anorectal dysmotility is common in advanced Parkinson's disease (PD), but there have been few evaluations in newly diagnosed PD patients. Methods We conducted anorectal manometric evaluations in 19 newly diagnosed, drug-naïve, early-stage PD patients. All of the PD patients were questioned regarding the presence of anorectal symptoms. Results Anorectal manometry was abnormal in 12 of the 19 patients. These abnormalities were more common in patients with more severe anorectal symptoms, as measured using a self-reported scale. However, more than 40% of patients with no or minimal symptoms also exhibited manometric abnormalities. Conclusions These results suggest that anorectal dysmotility manifests in many early-stage PD patients, which this represent evidence for the involvement of neuronal structures in such nonmotor manifestations in PD. PMID:23091527

Radiofrequency ablation versus resection for Barcelona clinic liver cancer very early/early stage hepatocellular carcinoma: a systematic review.

PubMed

He, Zhen-Xin; Xiang, Pu; Gong, Jian-Ping; Cheng, Nan-Sheng; Zhang, Wei

2016-01-01

To compare the long-term survival outcomes of radiofrequency ablation and liver resection for single very early/early stage hepatocellular carcinoma (HCC). The Cochrane Library (Issue 3, 2015), Embase (1974 to March 15, 2015), PubMed (1950 to March 15, 2015), Web of Science (1900 to March 15, 2015), and Chinese Biomedical Literature Database (1978 to March 15, 2015) were searched to identify relevant trials. Only trials that compared radiofrequency ablation and liver resection for single very early stage (≤2 cm) or early stage (≤3 cm) HCC according to the Barcelona clinic liver cancer (BCLC) staging system were considered for inclusion in this review. The primary outcomes that we analyzed were the 3-year and 5-year overall survival (OS) rates, and the secondary outcomes that we analyzed were the 3-year and 5-year disease-free survival (DFS) rates. Review Manager 5.3 was used to perform a cumulative meta-analysis. Possible publication bias was examined using a funnel plot. A random-effects model was applied to summarize the various outcomes. Six studies involving 947 patients were identified that compared radiofrequency ablation (n=528) to liver resection (n=419) for single BCLC very early HCC. In these six studies, the rates of 3-year OS, 5-year OS, 3-year DFS, and 5-year DFS were significantly lower in the radiofrequency ablation group than in the liver resection group (risk ratio [RR] =0.90, 95% confidence interval [CI]: 0.83-0.98, P=0.01; RR =0.84, 95% CI: 0.75-0.95, P=0.004; RR =0.77, 95% CI: 0.60-0.98, P=0.04; and RR =0.70, 95% CI: 0.52-0.94, P=0.02, respectively). Ten studies involving 2,501 patients were identified that compared radiofrequency ablation (n=1,476) to liver resection (n=1,025) for single BCLC early HCC. In these ten studies, the rates of 3-year OS, 5-year OS, 3-year DFS, and 5-year DFS were also significantly lower in the radiofrequency ablation group than in the liver resection group (RR =0.93, 95% CI: 0.88-0.98, P=0.003; RR =0.84, 95% CI

Radiofrequency ablation versus resection for Barcelona clinic liver cancer very early/early stage hepatocellular carcinoma: a systematic review

PubMed Central

He, Zhen-Xin; Xiang, Pu; Gong, Jian-Ping; Cheng, Nan-Sheng; Zhang, Wei

2016-01-01

Aim To compare the long-term survival outcomes of radiofrequency ablation and liver resection for single very early/early stage hepatocellular carcinoma (HCC). Methods The Cochrane Library (Issue 3, 2015), Embase (1974 to March 15, 2015), PubMed (1950 to March 15, 2015), Web of Science (1900 to March 15, 2015), and Chinese Biomedical Literature Database (1978 to March 15, 2015) were searched to identify relevant trials. Only trials that compared radiofrequency ablation and liver resection for single very early stage (≤2 cm) or early stage (≤3 cm) HCC according to the Barcelona clinic liver cancer (BCLC) staging system were considered for inclusion in this review. The primary outcomes that we analyzed were the 3-year and 5-year overall survival (OS) rates, and the secondary outcomes that we analyzed were the 3-year and 5-year disease-free survival (DFS) rates. Review Manager 5.3 was used to perform a cumulative meta-analysis. Possible publication bias was examined using a funnel plot. A random-effects model was applied to summarize the various outcomes. Results Six studies involving 947 patients were identified that compared radiofrequency ablation (n=528) to liver resection (n=419) for single BCLC very early HCC. In these six studies, the rates of 3-year OS, 5-year OS, 3-year DFS, and 5-year DFS were significantly lower in the radiofrequency ablation group than in the liver resection group (risk ratio [RR] =0.90, 95% confidence interval [CI]: 0.83–0.98, P=0.01; RR =0.84, 95% CI: 0.75–0.95, P=0.004; RR =0.77, 95% CI: 0.60–0.98, P=0.04; and RR =0.70, 95% CI: 0.52–0.94, P=0.02, respectively). Ten studies involving 2,501 patients were identified that compared radiofrequency ablation (n=1,476) to liver resection (n=1,025) for single BCLC early HCC. In these ten studies, the rates of 3-year OS, 5-year OS, 3-year DFS, and 5-year DFS were also significantly lower in the radiofrequency ablation group than in the liver resection group (RR =0.93, 95% CI: 0.88–0

Characteristics of Early Stages of Corrosion Fatigue in Aircraft Skin

DOT National Transportation Integrated Search

1996-02-01

SRI International is conducting research to characterize and quantitatively describe the early stages of corrosion fatigue in the fuselage skin of commercial aircraft. Specific objectives are to gain an improved deterministic understanding of the tra...

Effects of education on the progression of early- versus late-stage mild cognitive impairment.

PubMed

Ye, Byoung Seok; Seo, Sang Won; Cho, Hanna; Kim, Seong Yoon; Lee, Jung-Sun; Kim, Eun-Joo; Lee, Yunhwan; Back, Joung Hwan; Hong, Chang Hyung; Choi, Seong Hye; Park, Kyung Won; Ku, Bon D; Moon, So Young; Kim, Sangyun; Han, Seol-Heui; Lee, Jae-Hong; Cheong, Hae-Kwan; Na, Duk L

2013-04-01

Highly educated participants with normal cognition show lower incidence of Alzheimer's disease (AD) than poorly educated participants, whereas longitudinal studies involving AD have reported that higher education is associated with more rapid cognitive decline. We aimed to evaluate whether highly educated amnestic mild cognitive impairment (aMCI) participants show more rapid cognitive decline than those with lower levels of education. A total of 249 aMCI patients enrolled from 31 memory clinics using the standard assessment and diagnostic processes were followed with neuropsychological evaluation (duration 17.2 ± 8.8 months). According to baseline performances on memory tests, participants were divided into early-stage aMCI (-1.5 to -1.0 standard deviation (SD)) and late-stage aMCI (below -1.5 SD) groups. Risk of AD conversion and changes in neuropsychological performances according to the level of education were evaluated. Sixty-two patients converted to AD over a mean follow-up of 1.43 years. The risk of AD conversion was higher in late-stage aMCI than early-stage aMCI. Cox proportional hazard models showed that aMCI participants, and late-stage aMCI participants in particular, with higher levels of education had a higher risk of AD conversion than those with lower levels of education. Late-stage aMCI participants with higher education showed faster cognitive decline in language, memory, and Clinical Dementia Rating Sum of Boxes (CDR-SOB) scores. On the contrary, early-stage aMCI participants with higher education showed slower cognitive decline in MMSE and CDR-SOB scores. Our findings suggest that the protective effects of education against cognitive decline remain in early-stage aMCI and disappear in late-stage aMCI.

Black Willow

Treesearch

R. M. Krinard

1980-01-01

Black willow and other species of Salix together comprise a majority of the stocking. Cottonwood is the chief associate, particularly in the early stages, but green ash, sycamore, pecan, persimmon, waterlocust, American elm, baldcypress, red maple, sugarberry, box-elder, and in some areas, silver maple are invaders preceding the next successional stage.

The role of frugivorous bats in tropical forest succession.

PubMed

Muscarella, Robert; Fleming, Theodore H

2007-11-01

Discussion of successional change has traditionally focused on plants. The role of animals in producing and responding to successional change has received far less attention. Dispersal of plant propagules by animals is a fundamental part of successional change in the tropics. Here we review the role played by frugivorous bats in successional change in tropical forests. We explore the similarities and differences of this ecological service provided by New and Old World seed-dispersing bats and conclude with a discussion of their current economic and conservation implications. Our review suggests that frugivorous New World phyllostomid bats play a more important role in early plant succession than their Old World pteropodid counterparts. We propose that phyllostomid bats have shared a long evolutionary history with small-seeded early successional shrubs and treelets while pteropodid bats are principally dispersers of the seeds of later successional canopy fruits. When species of figs (Ficus) are involved in the early stages of primary succession (e.g. in the river meander system in Amazonia and on Krakatau, Indonesia), both groups of bats are important contributors of propagules. Because they disperse and sometimes pollinate canopy trees, pteropodid bats have a considerable impact on the economic value of Old World tropical forests; phyllostomid bats appear to make a more modest direct contribution to the economic value of New World tropical forests. Nonetheless, because they critically influence forest regeneration, phyllostomid bats make an important indirect contribution to the economic value of these forests. Overall, fruit-eating bats play important roles in forest regeneration throughout the tropics, making their conservation highly desirable.

Early infection risk with primary versus staged Hemodialysis Reliable Outflow (HeRO) graft implantation.

PubMed

Griffin, Andrew S; Gage, Shawn M; Lawson, Jeffrey H; Kim, Charles Y

2017-01-01

This study evaluated whether the use of a staged Hemodialysis Reliable Outflow (HeRO; Merit Medical, South Jordan, Utah) implantation strategy incurs increased early infection risk compared with conventional primary HeRO implantation. A retrospective review was performed of 192 hemodialysis patients who underwent HeRO graft implantation: 105 patients underwent primary HeRO implantation in the operating room, and 87 underwent a staged implantation where a previously inserted tunneled central venous catheter was used for guidewire access for the venous outflow component. Within the staged implantation group, 32 were performed via an existing tunneled hemodialysis catheter (incidentally staged), and 55 were performed via a tunneled catheter inserted across a central venous occlusion in an interventional radiology suite specifically for HeRO implantation (intentionally staged). Early infection was defined as episodes of bacteremia or HeRO infection requiring resection ≤30 days of HeRO implantation. For staged HeRO implantations, the median interval between tunneled catheter insertion and conversion to a HeRO graft was 42 days. The overall HeRO-related infection rate ≤30 days of implantation was 8.6% for primary HeRO implantation and 2.3% for staged implantations (P = .12). The rates of early bacteremia and HeRO resection requiring surgical resection were not significantly different between groups (P = .19 and P = .065, respectively), nor were age, gender, laterality, anastomosis to an existing arteriovenous access, human immunodeficiency virus status, diabetes, steroids, chemotherapy, body mass index, or graft location. None of the patient variables, techniques, or graft-related variables correlated significantly with the early infection rate. The staged HeRO implantation strategy did not result in an increased early infection risk compared with conventional primary implantation and is thus a reasonable strategy for HeRO insertion in hemodialysis patients

A Four-Stage Method for Developing Early Interventions for Alcohol among Aboriginal Adolescents

ERIC Educational Resources Information Center

Mushquash, Christopher J.; Comeau, M. Nancy; McLeod, Brian D.; Stewart, Sherry H.

2010-01-01

This paper details a four-stage methodology for developing early alcohol interventions for at-risk Aboriginal youth. Stage 1 was an integrative approach to Aboriginal education that upholds Aboriginal traditional wisdom supporting respectful relationships to the Creator, to the land and to each other. Stage 2 used quantitative methods to…

Stage-specific differences in secretory profile of mesenchymal stromal cells (MSCs) subjected to early- vs late-stage OA synovial fluid.

PubMed

Gómez-Aristizábal, A; Sharma, A; Bakooshli, M A; Kapoor, M; Gilbert, P M; Viswanathan, S; Gandhi, R

2017-05-01

Although, mesenchymal stromal cells (MSCs) are being clinically investigated for their use in osteoarthritis (OA), it is unclear whether their postulated therapeutic properties are equally effective in the early- and late-stages of OA. In this study we investigated MSC cytokine secretion post-exposure to synovial fluid (SF), obtained from early- vs late-stage knee OA patients to justify a potential patient stratification strategy to maximize MSC-mediated treatment effects. Subjects were recruited and categorized into early- [Kellgren-Lawrence (KL) grade I/II, n = 12] and late-stage (KL-III/IV, n = 12) knee OA groups. SF samples were obtained, and their proteome was tested using multiplex assays, after 3-days culture, with and without MSCs. SFs cultured without MSCs were used as a baseline to identify MSC-secreted factors into SFs cultured with MSCs. Linear mixed-effect models and non-parametric tests were used to identify alterations in the MSC secretome during exposure to OA SF (3-days). MSCs cultured for 3-days in 0.5% fetal bovine serum (FBS)-supplemented medium were used to compare SF results with culture medium. Following exposure to OA SF, the MSC secretome contained proteins that are involved in tissue repair, angiogenesis, chemotaxis, matrix remodeling and the clotting process. However, chemokine (C-X-C motif) ligand-8 (CXCL8; chemoattractant), interleukin-6 (IL6) and chemokine (C-C motif) ligand 2 (CCL2) were elevated in the MSC-secretome in response to early- vs late-stage OA SF. Early- vs late-stage OA SF samples elicit a differential MSC secretome response, arguing for stratification of OA patients to maximize MSC-mediated therapeutic effects. Copyright © 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Driving in Early-Stage Alzheimer's Disease: An Integrative Review of the Literature.

PubMed

Davis, Rebecca L; Ohman, Jennifer M

2017-03-01

One of the most difficult decisions for individuals with Alzheimer's disease (AD) is when to stop driving. Because driving is a fundamental activity linked to socialization, independent functioning, and well-being, making the decision to stop driving is not easy. Cognitive decline in older adults can lead to getting lost while driving, difficulty detecting and avoiding hazards, as well as increased errors while driving due to compromised judgment and difficulty in making decisions. The purpose of the current literature review was to synthesize evidence regarding how individuals with early-stage AD, their families, and providers make determinations about driving safety, interventions to increase driving safety, and methods to assist cessation and coping for individuals with early-stage AD. The evidence shows that changes in driving ability start early and progress throughout the trajectory of AD. Some individuals with mild cognitive impairment or early-stage AD may be safe to drive for a period of time. Support groups aimed at helping with the transition have been shown to be helpful for individuals who stop driving. Research and practice must support interventions to help individuals maintain safety while driving, as well as cope with driving cessation. [Res Gerontol Nurs. 2017; 10(2):86-100.]. Copyright 2016, SLACK Incorporated.

Improved early outcome for end-stage dilated cardiomyopathy in children.

PubMed

McMahon, Anne-Marie; van Doorn, Carin; Burch, Michael; Whitmore, Pauline; Neligan, Sophie; Rees, Philip; Radley-Smith, Rosemary; Goldman, Allan; Brown, Katherine; Cohen, Gordon; Tsang, Victor; Elliott, Martin; de Leval, Marc R

2003-12-01

To review the impact of management changes on the early outcomes of end-stage dilated cardiomyopathy in children. We conducted a retrospective study of all consecutive children with end-stage dilated cardiomyopathy who received hospital treatment since 1992. Over the past 3 years the following management changes were made: (1) more aggressive use of mechanical cardiac assistance; (2) high priority listing for transplantation; and (3) ABO incompatible transplants for infants. Outcomes for 46 patients admitted between 1992 and 1999 (group I) were compared with 53 patients between 2000 and March 2003 (group II). In group I, 12 (26%) patients received mechanical support with recovery in 3 and transplantation in 5 (1 died). In group II, 19 (36%) patients received extracorporeal membrane oxygenation, with recovery in 5 and transplantation in 12 (all survived). The use of mechanical assistance was associated with high morbidity related to bleeding, end-organ failure, and long-term mechanical ventilation. Five patients in group II received ABO incompatible transplants and all survived. There have been no episodes of rejection or need for increased immunosuppressive therapy. Hospital mortality has been significantly reduced (group I, 37% vs group II, 11%; P <.05). Recent refinements in the management of end-stage dilated cardiomyopathy in children have significantly reduced early mortality. Identification of markers of early myocardial recovery and development of mechanical devices for longer term and more physiologic support are essential to achieve further improvements in outcome.

Following iron speciation in the early stages of magnetite magnetosome biomineralization

DOE PAGES

Firlar, Emre; Perez-Gonzalez, Teresa; Olszewska, Agata; ...

2016-02-26

Understanding magnetosome magnetite biomineralization is of fundamental interest to devising the strategies for bioinspired synthesis of magnetic materials at the nanoscale. Thus, we investigated the early stages of magnetosome formation in this work and correlated the size and emergent crystallinity of magnetosome nanoparticles with the changes in chemical environment of iron and oxygen by utilizing advanced analytical electron microscopy techniques. We observed that magnetosomes in the early stages of biomineralization with the sizes of 5–10 nm were amorphous, with a majority of iron present as Fe 3+, indicative of ferric hydroxide. The magnetosomes with intermediate sizes showed partially crystalline structuremore » with a majority of iron present as Fe 3+ and trace amounts of Fe 2+. The fully maturated magnetosomes were indexed to magnetite. Furthermore, our approach provides spatially resolved structural and chemical information of individual magnetosomes with different particle sizes, attributed to magnetosomes at different stages of biomineralization.« less

Early stages of figure-ground segregation during perception of the face-vase.

PubMed

Pitts, Michael A; Martínez, Antígona; Brewer, James B; Hillyard, Steven A

2011-04-01

The temporal sequence of neural processes supporting figure-ground perception was investigated by recording ERPs associated with subjects' perceptions of the face-vase figure. In Experiment 1, subjects continuously reported whether they perceived the face or the vase as the foreground figure by pressing one of two buttons. Each button press triggered a probe flash to the face region, the vase region, or the borders between the two. The N170/vertex positive potential (VPP) component of the ERP elicited by probes to the face region was larger when subjects perceived the faces as figure. Preceding the N170/VPP, two additional components were identified. First, when the borders were probed, ERPs differed in amplitude as early as 110 msec after probe onset depending on subjects' figure-ground perceptions. Second, when the face or vase regions were probed, ERPs were more positive (at ∼ 150-200 msec) when that region was perceived as figure versus background. These components likely reflect an early "border ownership" stage, and a subsequent "figure-ground segregation" stage of processing. To explore the influence of attention on these stages of processing, two additional experiments were conducted. In Experiment 2, subjects selectively attended to the face or vase region, and the same early ERP components were again produced. In Experiment 3, subjects performed an identical selective attention task, but on a display lacking distinctive figure-ground borders, and neither of the early components were produced. Results from these experiments suggest sequential stages of processing underlying figure-ground perception, each which are subject to modifications by selective attention.

Laminarin improves developmental competence of porcine early stage embryos by inhibiting oxidative stress.

PubMed

Jiang, Hao; Liang, Shuang; Yao, Xue-Rui; Jin, Yong-Xun; Shen, Xing-Hui; Yuan, Bao; Zhang, Jia-Bao; Kim, Nam-Hyung

2018-04-23

Laminarin (LMA), a β-glucan mixture with good biocompatibility, improves the growth performance and immune response when used as food additives and nutraceuticals. The aim of the present research was to explore the effects of LMA on porcine early stage embryo development, as well as the underlying mechanisms. The results showed that the developmental competence of porcine early stage embryos was dramatically improved after LMA supplementation during the in vitro culture period. The presence of 20 μg/mL LMA during the in vitro culture period significantly improved cleavage rate, blastocyst formation rates, hatching rate, and total cell number in the blastocyst compared to that in the control group. Notably, LMA attenuated the intracellular reactive oxygen species generation induced by H 2 O 2 . Furthermore, LMA not only increased intracellular glutathione levels, but also ameliorated mitochondrial membrane potential. In addition, the expression of a zygotic genome activation related gene (YAP1), pluripotency-related genes (OCT4, NANOG, and SOX2), and hatching-related genes (COX2, GATA4, and ITGA5) were up-regulated following LMA supplementation during porcine early stage embryo development. These results demonstrate that LMA has beneficial effects on the development of porcine early stage embryos via regulation of oxidative stress. This evidence provides a novel method for embryo development improvement associated with exposure to LMA. Copyright © 2018 Elsevier Inc. All rights reserved.

Strong correlation between early stage atherosclerosis and electromechanical coupling of aorta

NASA Astrophysics Data System (ADS)

Liu, X. Y.; Yan, F.; Niu, L. L.; Chen, Q. N.; Zheng, H. R.; Li, J. Y.

2016-03-01

Atherosclerosis is the underlying cause of cardiovascular diseases that are responsible for many deaths in the world, and the early diagnosis of atherosclerosis is highly desirable. The existing imaging methods, however, are not capable of detecting the early stage of atherosclerosis development due to their limited spatial resolution. Using piezoresponse force microscopy (PFM), we show that the piezoelectric response of an aortic wall increases as atherosclerosis advances, while the stiffness of the aorta shows a less evident correlation with atherosclerosis. Furthermore, we show that there is strong correlation between the coercive electric field necessary to switch the polarity of the artery and the development of atherosclerosis. Thus by measuring the electromechanical coupling of the aortic wall, it is possible to probe atherosclerosis at the early stage of its development, not only improving the spatial resolution by orders of magnitude, but also providing comprehensive quantitative information on the biomechanical properties of the artery.

Monitoring late-successional forest biodiversity in the Pacific Northwest, U.S.A.

Treesearch

Thomas A. Spies; Jon R. Martin

2006-01-01

The era of ecosystem management for federal forest lands in the Pacific Northwest began in 1994 with the adoption of the Northwest Forest Plan. This plan was designed to maintain and restore species and ecosystems associated with late successional and old-growth forests on over 10 million ha. of federal lands in Washington, Oregon and California. The plan called for...

Applying NGS Data to Find Evolutionary Network Biomarkers from the Early and Late Stages of Hepatocellular Carcinoma

PubMed Central

Wu, Chia-Chou; Lin, Chih-Lung; Chen, Ting-Shou

2015-01-01

Hepatocellular carcinoma (HCC) is a major liver tumor (~80%), besides hepatoblastomas, angiosarcomas, and cholangiocarcinomas. In this study, we used a systems biology approach to construct protein-protein interaction networks (PPINs) for early-stage and late-stage liver cancer. By comparing the networks of these two stages, we found that the two networks showed some common mechanisms and some significantly different mechanisms. To obtain differential network structures between cancer and noncancer PPINs, we constructed cancer PPIN and noncancer PPIN network structures for the two stages of liver cancer by systems biology method using NGS data from cancer cells and adjacent noncancer cells. Using carcinogenesis relevance values (CRVs), we identified 43 and 80 significant proteins and their PPINs (network markers) for early-stage and late-stage liver cancer. To investigate the evolution of network biomarkers in the carcinogenesis process, a primary pathway analysis showed that common pathways of the early and late stages were those related to ordinary cancer mechanisms. A pathway specific to the early stage was the mismatch repair pathway, while pathways specific to the late stage were the spliceosome pathway, lysine degradation pathway, and progesterone-mediated oocyte maturation pathway. This study provides a new direction for cancer-targeted therapies at different stages. PMID:26366411

Developmental rate and behavior of early life stages of bighead carp and silver carp

USGS Publications Warehouse

Chapman, Duane C.; George, Amy E.

2011-01-01

The early life stages of Asian carp are well described by Yi and others (1988), but since these descriptions are represented by line drawings based only on live individuals and lacked temperature controls, further information on developmental time and stages is of use to expand understanding of early life stages of these species. Bighead carp and silver carp were cultured under two different temperature treatments to the one-chamber gas bladder stage, and a photographic guide is provided for bighead carp and silver carp embryonic and larval development, including notes about egg morphology and larval swimming behavior. Preliminary information on developmental time and hourly thermal units for each stage is also provided. Both carp species developed faster under warmer conditions. Developmental stages and behaviors are generally consistent with earlier works with the exception that strong vertical swimming immediately after hatching was documented in this report.

Early-\\x90stage Electrical Breakdown involving Tunneling

NASA Astrophysics Data System (ADS)

Hjalmarson, Harold; Moore, Chris; Schultz, Peter; Bussman, Ezra; Scrymgeour, David; Hopkins, Matt

The early stage of electrical breakdown from a surface is assumed to involve field emission. In real-world applications, the electrical field is often assumed to be increased by geometrical effects. In addition to these enhancement effects, contamination by adsorbates can lead to reductions in the effective work functions. To develop a physics-based understanding beyond the use of these empirical effects, the field emission currents at early times are being computed and measured. The calculations involve a solution of the Boltzmann equation, and the measurements involve a scanning tunneling microscope. Early results from this collaborative theoretical-experimental project will be described in this presentation. The presentation will focus on results for an ideal system with an absence of geometrical effects. Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Subthalamic Nucleus Deep Brain Stimulation in Early Stage Parkinson’s Disease

PubMed Central

Charles, David; Konrad, Peter E.; Neimat, Joseph S.; Molinari, Anna L.; Tramontana, Michael G.; Finder, Stuart G.; Gill, Chandler E.; Bliton, Mark J.; Kao, Chris C.; Phibbs, Fenna T.; Hedera, Peter; Salomon, Ronald M.; Cannard, Kevin R.; Wang, Lily; Song, Yanna; Davis, Thomas L.

2014-01-01

Background Deep brain stimulation (DBS) is an effective and approved therapy for advanced Parkinson’s disease (PD), and a recent study suggests efficacy in mid-stage disease. This manuscript reports the results of a pilot trial investigating preliminary safety and tolerability of DBS in early PD. Methods Thirty subjects with idiopathic PD (Hoehn & Yahr Stage II off medication), age 50–75, on medication ≥ 6 months but < 4 years, and without motor fluctuations or dyskinesias were randomized to optimal drug therapy (ODT) (n=15) or DBS+ODT (n=15). Co-primary endpoints were the time to reach a 4-point worsening from baseline in the UPDRS-III off therapy and the change in levodopa equivalent daily dose from baseline to 24 months. Results As hypothesized, the mean UPDRS total and part III scores were not significantly different on or off therapy at 24 months. The DBS+ODT group took less medication at all time points, and this reached maximum difference at 18 months. With a few exceptions, differences in neuropsychological functioning were not significant. Two subjects in the DBS+ODT group suffered serious adverse events; remaining adverse events were mild or transient. Conclusions This study demonstrates that subjects with early stage PD will enroll in and complete trials testing invasive therapies and provides preliminary evidence that DBS is well tolerated in early PD. The results of this trial provide the data necessary to design a large, phase III, double-blind, multicenter trial investigating the safety and efficacy of DBS in early PD. PMID:24768120

Early Stages of the Evolution of Life: a Cybernetic Approach

NASA Astrophysics Data System (ADS)

Melkikh, Alexey V.; Seleznev, Vladimir D.

2008-08-01

Early stages of the evolution of life are considered in terms of control theory. A model is proposed for the transport of substances in a protocell possessing the property of robustness with regard to changes in the environmental concentration of a substance.

Early stages of the evolution of life: a cybernetic approach.

PubMed

Melkikh, Alexey V; Seleznev, Vladimir D

2008-08-01

Early stages of the evolution of life are considered in terms of control theory. A model is proposed for the transport of substances in a protocell possessing the property of robustness with regard to changes in the environmental concentration of a substance.

Dual odontogenic origins develop at the early stage of rat maxillary incisor development.

PubMed

Kriangkrai, Rungarun; Iseki, Sachiko; Eto, Kazuhiro; Chareonvit, Suconta

2006-03-01

Developmental process of rat maxillary incisor has been studied through histological analysis and investigation of tooth-related gene expression patterns at initial tooth development. The tooth-related genes studied here are fibroblast growth factor-8 (Fgf-8), pituitary homeobox gene-2 (Pitx-2), sonic hedgehog (Shh), muscle segment homeobox-1 (Msx-1), paired box-9 (Pax-9) and bone morphogenetic protein-4 (Bmp-4). The genes are expressed in oral epithelium and/or ectomesenchyme at the stage of epithelial thickening to the early bud stage of tooth development. Both the histological observation and tooth-related gene expression patterns during early stage of maxillary incisor development demonstrate that dual odontogenic origins aligned medio-laterally in the medial nasal process develop, subsequently only single functional maxillary incisor dental placode forms. The cascade of tooth-related gene expression patterns in rat maxillary incisor studied here is quite similar to those of the previous studies in mouse mandibular molar, even though the origins of oral epithelium and ectomesenchyme involved in development of maxillary incisor and mandibular molar are different. Thus, we conclude that maxillary incisor and mandibular molar share a similar signaling control of Fgf-8, Pitx-2, Shh, Msx-1, Pax-9 and Bmp-4 genes at the stage of oral epithelial thickening to the early bud stage of tooth development.

Early Stages of Figure–Ground Segregation during Perception of the Face–Vase

PubMed Central

Pitts, Michael A.; Martínez, Antígona; Brewer, James B.; Hillyard, Steven A.

2011-01-01

The temporal sequence of neural processes supporting figure–ground perception was investigated by recording ERPs associated with subjects’ perceptions of the face–vase figure. In Experiment 1, subjects continuously reported whether they perceived the face or the vase as the foreground figure by pressing one of two buttons. Each button press triggered a probe flash to the face region, the vase region, or the borders between the two. The N170/vertex positive potential (VPP) component of the ERP elicited by probes to the face region was larger when subjects perceived the faces as figure. Preceding the N170/VPP, two additional components were identified. First, when the borders were probed, ERPs differed in amplitude as early as 110 msec after probe onset depending on subjects’ figure–ground perceptions. Second, when the face or vase regions were probed, ERPs were more positive (at ~150–200 msec) when that region was perceived as figure versus background. These components likely reflect an early “border ownership” stage, and a subsequent “figure–ground segregation” stage of processing. To explore the influence of attention on these stages of processing, two additional experiments were conducted. In Experiment 2, subjects selectively attended to the face or vase region, and the same early ERP components were again produced. In Experiment 3, subjects performed an identical selective attention task, but on a display lacking distinctive figure–ground borders, and neither of the early components were produced. Results from these experiments suggest sequential stages of processing underlying figure–ground perception, each which are subject to modifications by selective attention. PMID:20146604

Swimming speed alteration in the early developmental stages of Paracentrotus lividus sea urchin as ecotoxicological endpoint.

PubMed

Morgana, Silvia; Gambardella, Chiara; Falugi, Carla; Pronzato, Roberto; Garaventa, Francesca; Faimali, Marco

2016-04-01

Behavioral endpoints have been used for decades to assess chemical impacts at concentrations unlikely to cause mortality. With recently developed techniques, it is possible to investigate the swimming behavior of several organisms under laboratory conditions. The aims of this study were: i) assessing for the first time the feasibility of swimming speed analysis of the early developmental stage sea urchin Paracentrotus lividus by an automatic recording system ii) investigating any Swimming Speed Alteration (SSA) on P. lividus early stages exposed to a chemical reference; iii) identifying the most suitable stage for SSA test. Results show that the swimming speed of all the developmental stages was easily recorded. The swimming speed was inhibited as a function of toxicant concentration. Pluteus were the most appropriate stage for evaluating SSA in P. lividus as ecotoxicological endpoint. Finally, swimming of sea urchin early stages represents a sensitive endpoint to be considered in ecotoxicological investigations. Copyright © 2016 Elsevier Ltd. All rights reserved.

Disentangling the environmental heterogeneity, floristic distinctiveness and current threats of tropical dry forests in Colombia

NASA Astrophysics Data System (ADS)

González-M, Roy; García, Hernando; Isaacs, Paola; Cuadros, Hermes; López-Camacho, René; Rodríguez, Nelly; Pérez, Karen; Mijares, Francisco; Castaño-Naranjo, Alejandro; Jurado, Rubén; Idárraga-Piedrahíta, Álvaro; Rojas, Alicia; Vergara, Hernando; Pizano, Camila

2018-04-01

Tropical dry forests (TDFs) have been defined as a single biome occurring mostly in the lowlands where there is a marked period of drought during the year. In the Neotropics, dry forests occur across contrasting biogeographical regions that contain high beta diversity and endemism, but also strong anthropogenic pressures that threaten their biodiversity and ecological integrity. In Colombia, TDFs occur across six regions with contrasting soils, climate, and anthropogenic pressures, therefore being ideal for studying how these variables relate to dry forest species composition, successional stage and conservation status. Here, we explore the variation in climate and soil conditions, floristic composition, forest fragment size and shape, successional stage and anthropogenic pressures in 571 dry forest fragments across Colombia. We found that TDFs should not be classified solely on rainfall seasonality, as high variation in precipitation and temperature were correlated with soil characteristics. In fact, based on environmental factors and floristic composition, the dry forests of Colombia are clustered in three distinctive groups, with high species turnover across and within regions, as reported for other TDF regions of the Neotropics. Widely distributed TDF species were found to be generalists favored by forest disturbance and the early successional stages of dry forests. On the other hand, TDF fragments were not only small in size, but highly irregular in shape in all regions, and comprising mostly early and intermediate successional stages, with very little mature forest left at the national level. At all sites, we detected at least seven anthropogenic disturbances with agriculture, cattle ranching and human infrastructure being the most pressing disturbances throughout the country. Thus, although environmental factors and floristic composition of dry forests vary across regions at the national level, dry forests are equally threatened by deforestation, degradation

Early-stage aeolian protodune development and migration

NASA Astrophysics Data System (ADS)

Nield, J. M.; Baddock, M. C.; Wiggs, G.

2017-12-01

Early-stage bedforms, or protodunes, can be observed to form on sandy beaches, desert gravels or superimposed on the surfaces of larger dunes and can develop topography of 0.1 m or more over several hours. These protodunes are the precursors to embryo and eventually mature dunes, and so it is important to understand how feedbacks between flow, transport and form contribute to this development sequence. Whilst theory and conceptual models have offered some explanation for protodune existence and development, we know surprisingly little about how these bedforms initiate and migrate because it is difficult to measure small changes in form (millimetres; seconds) on highly active surfaces of limited topographic expression. Here, we employ terrestrial laser scanning (TLS) to measure morphological change at the high frequency and spatial resolution (sub-millimetre) required to gain new insights into protodune behaviour. Along with TLS derived saltation and surface moisture, additional sediment flux and windspeed measurements help to elucidate how the protodune topography interacts with airflow and sand transport. We focus on a number of coastal bedforms in various development stages including a 0.06 m high protodune which grew vertically by 0.005 m in two hours with the switch from erosion to deposition identified to occur at a point 0.07 m upwind of the crest. This growth was associated with a reduction in time-averaged sediment flux of 18% over the crestal region. We also observed a decline in lower stoss slope steepness (by 3°) and a steepening of the lee slope, indicating a reshaping of initial protodune form towards the morphology of a more mature dune. Our findings highlight the crucial role of form-flow feedbacks, even on very small bedforms, in driving early-stage bedform growth and development, and show how the use of high resolution TLS to measure both surface topography and grains moving above the surface, can offer new insights into a long standing deficiency

Funding opportunities for investigators in the early stages of career development.

PubMed

Sumandea, C Amelia; Balke, C William

2009-03-10

Many sources of advice and guidance are available to the early career investigator. Generally, mentors serve as the primary source of information, although program and review officers are the most underutilized resources. This article organizes these opportunities to enable early career investigators to plot a rational trajectory for career success. A list of the major agencies that provide grant support for early career investigators is included. In addition, funding opportunities are organized on the basis of the stage in career development pathway and the type of terminal degree.

Flexibility in Early Stage Design of U. S. Navy Ships: An Analysis of Options

DTIC Science & Technology

2011-01-01

Flexibility in Early Stage Design of US Navy Ships: An Analysis of Options by Jonathan Page B.S., Systems Engineering, US Naval Academy, 2002...8217C/ v = (;!;!: ;: Pat Hale Director, Systems Design and Ma~ement Fellows Program E~i_yfering.S~~pivi~i~ Acceptedby...2. REPORT TYPE 3. DATES COVERED 00-00-2012 to 00-00-2012 4. TITLE AND SUBTITLE Flexibility in Early Stage Design of U. S. Navy Ships: An

Morphological and histomorphological structures of testes and ovaries in early developmental stages of the silkworm, Bombyx mori.

PubMed

Sakai, Hiroki; Kirino, Yohei; Katsuma, Susumu; Aoki, Fugaku; Suzuki, Masataka G

2016-01-01

The gonad develops as a testis in male or an ovary in female. In the silkworm, B. mori , little is known about testis and ovary in the embryonic stages and early larval stages. In this study, we performed morphological and histomorphological observations of ovaries and testes from the late embryonic stage to the 1st instar larval stage. Results obtained with lack of accurate information on sex of examined individuals may be misleading, thus we performed phenotypic observations of gonads by utilizing sex-limited strain that enables us to easily discriminate female embryos from male ones based on those egg colors. In testis, four testicular follicles were clearly observed in the testis at the first instar larval stage, and boundary layers were formed between the testicular follicles. At the late embryonic stage, the testis consisted of four testicular follicles, while the boundary layers were still obscure. In ovary, four ovarioles were easily recognizable in the ovary at the first instar larval stage, and boundary layers were formed between the ovarioles. However, in the late embryonic stage, it was quite difficult to identify four ovarioles. Morphological characteristics were almost similar between testis and ovary in early developmental stages. Our present study demonstrates that the most reliable difference between testis and ovary in early developmental stages is the attaching point of the duct. Formation and development of the duct may be sensitive to the sex-determining signal and display sexual dimorphism in early embryonic stages.

Financial Implication of Radioactive Iodine Therapy for Early-Stage Papillary Thyroid Cancer.

PubMed

Al-Qurayshi, Zaid; Bu Ali, Daniah; Srivastav, Sudesh; Kandil, Emad

2017-01-01

The aim of this study was to evaluate disease-specific survival and cost related to radioactive iodine therapy (RAI) utilization in patients with early-stage papillary thyroid carcinoma (PTC). This was a retrospective cohort study using the Surveillance, Epidemiology, and End Results (SEER) database, 2004-2012. A total of 38,374 patients with PTC were identified. Of those, 56.3% had adjuvant RAI. RAI administration was not associated with a survival advantage in patients with PTC stage I (hazard ratio [HR] 1.26, 95% confidence interval [CI] 0.11, 14.54; p = 0.85) or stage II (HR 0.50, 95% CI 0.05, 4.88; p = 0.55). Patients with PTC stage III who underwent adjuvant RAI had an improved survival (HR 0.30, 95% CI 0.10, 0.91; p = 0.033). In 2012, RAI was used in 45.5% of patients with stage I and in 71.4% of patients with stage II. The total expenditure on adjuvant RAI for PTC stage I throughout the study period was estimated to be USD 82.3 million with an annual average of USD 9.1 (±2.0) million/year. If the decline rate in the utilization of RAI continued, the model projected that the annual expenditure would decrease by USD 0.14 million/year. There is a high prevalence of adjuvant RAI utilization for early-stage PTC that is causing financial burden on the health system with no evidence of survival benefit. © 2017 S. Karger AG, Basel.

Socioeconomic position and surgery for early-stage non-small-cell lung cancer: A population-based study in Denmark.

PubMed

Kærgaard Starr, Laila; Osler, Merete; Steding-Jessen, Marianne; Lidegaard Frederiksen, Birgitte; Jakobsen, Erik; Østerlind, Kell; Schüz, Joachim; Johansen, Christoffer; Oksbjerg Dalton, Susanne

2013-03-01

To examine possible associations between socioeconomic position and surgical treatment of patients with early-stage non-small-cell lung cancer (NSCLC). In a register-based clinical cohort study, patients with early-stage (stages I-IIIa) NSCLC were identified in the Danish Lung Cancer Register 2001-2008 (date of diagnosis, histology, stage, and treatment), the Central Population Register (vital status), the Integrated Database for Labour Market Research (socioeconomic position), and the Danish Hospital Discharge Register (comorbidity). Logistic regression analyses were performed overall and separately for stages I, II and IIIa. Of the 5538 eligible patients with stages I-IIIa NSCLC diagnosed 2001-2008, 53% underwent surgery. Higher stage, older age, being female and diagnosis early in the study period were associated with higher odds for not receiving surgery. Low disposable income was associated with greater odds for no surgery in stage I and stage II patients as was living alone for stage I patients. Comorbidity, a short diagnostic interval and small diagnostic volume were all associated with higher odds for not undergoing surgery; but these factors did not appear to explain the association with income or living alone for early-stage NSCLC patients. Early-stage NSCLC patients with low income or who live alone are less likely to undergo surgery than those with a high income or who live with a partner, even after control for possible explanatory factors. Thus, even in a health care system with free, equal access to health services, disadvantaged groups are less likely to receive surgery for lung cancer. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Metamorphic density controls on early-stage subduction dynamics

NASA Astrophysics Data System (ADS)

Duesterhoeft, Erik; Oberhänsli, Roland; Bousquet, Romain

2013-04-01

Subduction is primarily driven by the densification of the downgoing oceanic slab, due to dynamic P-T-fields in subduction zones. It is crucial to unravel slab densification induced by metamorphic reactions to understand the influence on plate dynamics. By analyzing the density and metamorphic structure of subduction zones, we may gain knowledge about the driving, metamorphic processes in a subduction zone like the eclogitization (i.e., the transformation of a MORB to an eclogite), the breakdown of hydrous minerals and the release of fluid or the generation of partial melts. We have therefore developed a 2D subduction zone model down to 250 km that is based on thermodynamic equilibrium assemblage computations. Our model computes the "metamorphic density" of rocks as a function of pressure, temperature and chemical composition using the Theriak-Domino software package at different time stages. We have used this model to investigate how the hydration, dehydration, partial melting and fractionation processes of rocks all influence the metamorphic density and greatly depend on the temperature field within subduction systems. These processes are commonly neglected by other approaches (e.g., gravitational or thermomechanical in nature) reproducing the density distribution within this tectonic setting. The process of eclogitization is assumed as being important to subduction dynamics, based on the very high density (3.6 g/cm3) of eclogitic rocks. The eclogitization in a MORB-type crust is possible only if the rock reaches the garnet phase stability field. This process is primarily temperature driven. Our model demonstrates that the initiation of eclogitization of the slab is not the only significant process that makes the descending slab denser and is responsible for the slab pull force. Indeed, our results show that the densification of the downgoing lithospheric mantle (due to an increase of pressure) starts in the early subduction stage and makes a significant

Dyadic Intervention for Family Caregivers and Care Receivers in Early-Stage Dementia

ERIC Educational Resources Information Center

Whitlatch, Carol J.; Judge, Katherine; Zarit, Steven H.; Femia, Elia

2006-01-01

Purpose: The Early Diagnosis Dyadic Intervention (EDDI) program provides a structured, time-limited protocol of one-on-one and dyadic counseling for family caregivers and care receivers who are in the early stages of dementia. The goals and procedures of EDDI are based on previous research suggesting that dyads would benefit from an intervention…

Towards non-invasive diagnostic imaging of early-stage Alzheimer's disease

NASA Astrophysics Data System (ADS)

Viola, Kirsten L.; Sbarboro, James; Sureka, Ruchi; de, Mrinmoy; Bicca, Maíra A.; Wang, Jane; Vasavada, Shaleen; Satpathy, Sreyesh; Wu, Summer; Joshi, Hrushikesh; Velasco, Pauline T.; Macrenaris, Keith; Waters, E. Alex; Lu, Chang; Phan, Joseph; Lacor, Pascale; Prasad, Pottumarthi; Dravid, Vinayak P.; Klein, William L.

2015-01-01

One way to image the molecular pathology in Alzheimer's disease is by positron emission tomography using probes that target amyloid fibrils. However, these fibrils are not closely linked to the development of the disease. It is now thought that early-stage biomarkers that instigate memory loss are composed of Aβ oligomers. Here, we report a sensitive molecular magnetic resonance imaging contrast probe that is specific for Aβ oligomers. We attach oligomer-specific antibodies onto magnetic nanostructures and show that the complex is stable and binds to Aβ oligomers on cells and brain tissues to give a magnetic resonance imaging signal. When intranasally administered to an Alzheimer's disease mouse model, the probe readily reached hippocampal Aβ oligomers. In isolated samples of human brain tissue, we observed a magnetic resonance imaging signal that distinguished Alzheimer's disease from controls. Such nanostructures that target neurotoxic Aβ oligomers are potentially useful for evaluating the efficacy of new drugs and ultimately for early-stage Alzheimer's disease diagnosis and disease management.

Breeding bird response to juniper woodland expansion

USGS Publications Warehouse

Rosenstock, Steven S.; van Riper, Charles

2001-01-01

In recent times, pinyon (Pinus spp.)-juniper (Juniperus spp.) woodlands have expanded into large portions of the Southwest historically occupied by grassland vegetation. From 1997-1998, we studied responses of breeding birds to one-seed juniper (J. monosperma) woodland expansion at 2 grassland study areas in northern Arizona. We sampled breeding birds in 3 successional stages along a grassland-woodland gradient: un-invaded grassland, grassland undergoing early stages of juniper establishment, and developing woodland. Species composition varied greatly among successional stages and was most different between endpoints of the gradient. Ground-nesting grassland species predominated in uninvaded grassland but declined dramatically as tree density increased. Tree- and cavity-nesting species increased with tree density and were most abundant in developing woodland. Restoration of juniper-invaded grasslands will benefit grassland-obligate birds and other wildlife.

Alternatives to the fish early life-stage test: Developing a conceptual model for early fish development

EPA Science Inventory

Chronic fish toxicity is a key parameter for hazard classification and environmental risk assessment of chemicals, and the OECD 210 fish early life-stage (FELS) test is the primary guideline test used for various international regulatory programs. There exists a need to develop ...

Role of chemotherapy and targeted therapy in early-stage non-small cell lung cancer.

PubMed

Nagasaka, Misako; Gadgeel, Shirish M

2018-01-01

Adjuvant platinum based chemotherapy is accepted as standard of care in stage II and III non-small cell lung cancer (NSCLC) patients and is often considered in patients with stage IB disease who have tumors ≥ 4 cm. The survival advantage is modest with approximately 5% at 5 years. Areas covered: This review article presents relevant data regarding chemotherapy use in the perioperative setting for early stage NSCLC. A literature search was performed utilizing PubMed as well as clinical trial.gov. Randomized phase III studies in this setting including adjuvant and neoadjuvant use of chemotherapy as well as ongoing trials on targeted therapy and immunotherapy are also discussed. Expert commentary: With increasing utilization of screening computed tomography scans, it is possible that the percentage of early stage NSCLC patients will increase in the coming years. Benefits of adjuvant chemotherapy in early stage NSCLC patients remain modest. There is a need to better define patients most likely to derive survival benefit from adjuvant therapy and spare patients who do not need adjuvant chemotherapy due to the toxicity of such therapy. Trials for adjuvant targeted therapy, including adjuvant EGFR-TKI trials and trials of immunotherapy drugs are ongoing and will define the role of these agents as adjuvant therapy.

Successional change in photosynthetic capacities after wildfires across the North American boreal forests

NASA Astrophysics Data System (ADS)

Tahara, N.; Ueyama, M.; Iwata, H.; Ichii, K.; Harazono, Y.; Nagano, H.

2015-12-01

Wildfire is a major disturbance across the North American boreal forests. Canopy ecophysiology is important to understand recovery of carbon dioxide and water vapor fluxes after wildfires. We developed a big-leaf model coupled photosynthesis (Farquhar et al., 1980) and stomatal conductance (Ball et al., 1987) models. We inputted eddy covariance data from fire chronosequence across the North American boreal forests into the big-leaf model for optimizing parameters: maximum carboxylation rate at 25℃ (Vcmax25) and stomatal conductance parameters. The model was optimized with a global optimization technique: SCE-UA method (Duan et al., 1994). The estimated canopy-scale parameters were then downscaled into a leaf scale (vcmax25; values per sun leaf area) using a two-leaf radiation transfer model (de Pury and Farquhar, 1997) and leaf area index. We used 6 sites from two fire chronosequence in Alaska (1~, 3~, 5~, 15~ and 80~ years after fire; Liu et al., 2005; Iwata et al., 2011) and 6 sites from a Canadian chronosequence study (6~, 15~, 23~, 40~ and 74~ years after fire; Goulden et al., 2010). Preliminary results showed clear seasonal variations in canopy-scale Vcmax25 with the maximum during the summer. In Alaska, the downscaled vcmax25 for four years after fire exceeded those of mature forests, indicating that the photosynthetic capacity recovered quickly in the early successional stage. This quick recovery was not seen in gross primary productivity. We will show the variations of the ecophysiological parameters in terms of environment conditions and stand age. References Ball et al., 1987: In Progress in Photosynthesis Research, 221-224. de Pury and Farquhar, 1997: Plant, Cell and Environ., 20, 537-557. Duan et al., 1994: J. Hydrology, 158, 265-284. Farquhar et al., 1980: Planta, 149, 78-90. Goulden et al., 2010: Global Change Biol., 17, 855-871. Iwata et al., 2011: SOLA., 7, 105-108. Liu et al., 2005: J. Geophys. Res., 110, D13101.

Clinical and dosimetric implications of intensity-modulated radiotherapy for early-stage glottic carcinoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ward, Matthew Christopher, E-mail: wardm3@ccf.org; Pham, Yvonne D.; Kotecha, Rupesh

2016-04-01

Conventional parallel-opposed radiotherapy (PORT) is the established standard technique for early-stage glottic carcinoma. However, case reports have reported the utility of intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) with or without image guidance (image-guided radiotherapy, IGRT) in select patients. The proposed advantages of IMRT/VMAT include sparing of the carotid artery, thyroid gland, and the remaining functional larynx, although these benefits remain unclear. The following case study presents a patient with multiple vascular comorbidities treated with VMAT for early-stage glottic carcinoma. A detailed explanation of the corresponding treatment details, dose-volume histogram (DVH) analysis, and a review of the relevant literaturemore » are provided. Conventional PORT remains the standard of care for early-stage glottic carcinoma. IMRT or VMAT may be beneficial for select patients, although great care is necessary to avoid a geographical miss. Clinical data supporting the benefit of CRT are lacking. Therefore, these techniques should be used with caution and only in selected patients.« less

New features of triacylglycerol biosynthetic pathways of peanut seeds in early developmental stages.

PubMed

Yu, Mingli; Liu, Fengzhen; Zhu, Weiwei; Sun, Meihong; Liu, Jiang; Li, Xinzheng

2015-11-01

The peanut (Arachis hypogaea L.) is one of the three most important oil crops in the world due to its high average oil content (50 %). To reveal the biosynthetic pathways of seed oil in the early developmental stages of peanut pods with the goal of improving the oil quality, we presented a method combining deep sequencing analysis of the peanut pod transcriptome and quantitative real-time PCR (RT-PCR) verification of seed oil-related genes. From the sequencing data, approximately 1500 lipid metabolism-associated Unigenes were identified. The RT-PCR results quantified the different expression patterns of these triacylglycerol (TAG) synthesis-related genes in the early developmental stages of peanut pods. Based on these results and analysis, we proposed a novel construct of the metabolic pathways involved in the biosynthesis of TAG, including the Kennedy pathway, acyl-CoA-independent pathway and proposed monoacylglycerol pathway. It showed that the biosynthetic pathways of TAG in the early developmental stages of peanut pods were much more complicated than a simple, unidirectional, linear pathway.

Clinical Phenotype Predicts Early Staged Bilateral Deep Brain Stimulation in Parkinson’s Disease

PubMed Central

Sung, Victor W.; Watts, Ray L.; Schrandt, Christian J.; Guthrie, Stephanie; Wang, Deli; Amara, Amy W.; Guthrie, Barton L.; Walker, Harrison C.

2014-01-01

Object While many centers place bilateral DBS systems simultaneously, unilateral STN DBS followed by a staged contralateral procedure has emerged as a treatment option for many patients. However little is known about whether the preoperative phenotype predicts when staged placement of a DBS electrode in the opposite subthalamic nucleus will be required. We aimed to determine whether preoperative clinical phenotype predicts early staged placement of a second subthalamic deep brain stimulation (DBS) electrode in patients who undergo unilateral subthalamic DBS for Parkinson's disease (PD). Methods Eighty-two consecutive patients with advanced PD underwent unilateral subthalamic DBS contralateral to the most affected hemibody and had at least 2 years of follow-up. Multivariate logistic regression determined preoperative characteristics that predicted staged placement of a second electrode in the opposite subthalamic nucleus. Preoperative measurements included aspects of the Unified Parkinson Disease Rating Scale (UPDRS), motor asymmetry index, and body weight. Results At 2 years follow-up, 28 of the 82 patients (34%) had undergone staged placement of a contralateral electrode while the remainder chose to continue with unilateral stimulation. Statistically significant improvements in UPDRS total and part 3 scores were retained at the end of the 2 year follow-up period in both subsets of patients. Multivariate logistic regression showed that the most important predictors for early staged placement of a second subthalamic stimulator were low asymmetry index (odds ratio 13.4; 95% confidence interval 2.8, 64.9), high tremor subscore (OR 7.2; CI 1.5, 35.0), and low body weight (OR 5.5; CI 1.4, 22.3). Conclusions This single center study provides evidence that elements of the preoperative PD phenotype predict whether patients will require early staged bilateral subthalamic DBS. These data may aid in the management of patients with advanced PD who undergo subthalamic DBS. PMID

Ordinary High Flows and the Stage-Discharge Relationship in the Arid West Region

DTIC Science & Technology

2011-07-01

vegetation species , percent cover, and successional stage (Figure 4B). Above the active floodplain, the 100-year floodplain is characterized by well...vegetation (Figure 5A) and minimal signs of recent flooding. However, flow indicators such as drift (Figure 5B) or fine sediment deposits along tree bark...Hard-leaved evergreen trees and shrubs Alfisols and Mollisols Tropical/ Subtropical Desert Santa Maria River, Hassayampa River, and Mojave River

Metabolomic Markers of Altered Nucleotide Metabolism in Early Stage Adenocarcinoma

PubMed Central

Wikoff, William R.; Grapov, Dmitry; Fahrmann, Johannes F.; DeFelice, Brian; Rom, William; Pass, Harvey; Kim, Kyoungmi; Nguyen, UyenThao; Taylor, Sandra L.; Kelly, Karen; Fiehn, Oliver; Miyamoto, Suzanne

2015-01-01

Adenocarcinoma, a type of non-small-cell lung cancer (NSCLC), is the most frequently diagnosed lung cancer and the leading cause of lung cancer mortality in the United States. It is well documented that biochemical changes occur early in the transition from normal to cancer cells, but the extent to which these alterations affect tumorigenesis in adenocarcinoma remains largely unknown. Herein we describe the application of mass spectrometry and multivariate statistical analysis in one of the largest biomarker research studies to date aimed at distinguishing metabolic differences between malignant and non-malignant lung tissue. Gas chromatography time-of-flight mass spectrometry was used to measure 462 metabolites in 39 malignant and non-malignant lung tissue pairs from current or former smokers with early stage (Stage IA–IB) adenocarcinoma. Statistical mixed effects models, orthogonal partial least squares discriminant analysis and network integration, were used to identify key cancer-associated metabolic perturbations in adenocarcinoma compared to non-malignant tissue. Cancer-associated biochemical alterations were characterized by: 1) decreased glucose levels, consistent with the Warburg effect, 2) changes in cellular redox status highlighted by elevations in cysteine and antioxidants, alpha- and gamma-tocopherol, 3) elevations in nucleotide metabolites 5,6-dihydrouracil and xanthine suggestive of increased dihydropyrimidine dehydrogenase and xanthine oxidoreductase activity, 4) increased 5'-deoxy-5'-methylthioadenosine levels indicative of reduced purine salvage and increased de novo purine synthesis and 5) coordinated elevations in glutamate and UDP-N-acetylglucosamine suggesting increased protein glycosylation. The present study revealed distinct metabolic perturbations associated with early stage lung adenocarcinoma which may provide candidate molecular targets for personalizing therapeutic interventions and treatment efficacy monitoring. PMID:25657018

Tau PET binding distinguishes patients with early-stage posterior cortical atrophy from amnestic Alzheimer disease dementia

PubMed Central

Day, Gregory S.; Gordon, Brian A.; Jackson, Kelley; Christensen, Jon J.; Ponisio, Maria Rosana; Su, Yi; Ances, Beau M; Benzinger, Tammie L.S.; Morris, John C.

2017-01-01

Background Flortaucipir (tau) PET binding distinguishes individuals with clinically well-established posterior cortical atrophy (PCA) due to Alzheimer disease (AD) from cognitively normal (CN) controls. However, it is not known whether tau PET binding patterns differentiate individuals with PCA from those with amnestic AD, particularly early in the symptomatic stages of disease. Methods Flortaucipir and florbetapir (β-amyloid) PET-imaging were performed in individuals with early-stage PCA (N=5), amnestic AD dementia (N=22), and CN controls (N=47). Average tau and β-amyloid deposition were quantified using standard uptake value ratios and compared at a voxel-wise level, controlling for age. Results PCA patients (median age-at-onset, 59 [51–61] years) were younger at symptom-onset than similarly-staged individuals with amnestic AD (75 [60–85] years) or CN controls (73 [61–90] years; p=0.002). Flortaucipir uptake was higher in individuals with early-stage symptomatic PCA versus those with early-stage amnestic AD or CN controls, and greatest in posterior regions. Regional elevations in florbetapir were observed in areas of greatest tau deposition in PCA patients. Conclusions and Relevance Flortaucipir uptake distinguished individuals with PCA and amnestic AD dementia early in the symptomatic course. The posterior brain regions appear to be uniquely vulnerable to tau deposition in PCA, aligning with clinical deficits that define this disease subtype. PMID:28394771

Tau-PET Binding Distinguishes Patients With Early-stage Posterior Cortical Atrophy From Amnestic Alzheimer Disease Dementia.

PubMed

Day, Gregory S; Gordon, Brian A; Jackson, Kelley; Christensen, Jon J; Rosana Ponisio, Maria; Su, Yi; Ances, Beau M; Benzinger, Tammie L S; Morris, John C

2017-01-01

Flortaucipir (tau) positron emission tomography (PET) binding distinguishes individuals with clinically well-established posterior cortical atrophy (PCA) due to Alzheimer disease (AD) from cognitively normal (CN) controls. However, it is not known whether tau-PET binding patterns differentiate individuals with PCA from those with amnestic AD, particularly early in the symptomatic stages of disease. Flortaucipir and florbetapir (β-amyloid) PET imaging were performed in individuals with early-stage PCA (N=5), amnestic AD dementia (N=22), and CN controls (N=47). Average tau and β-amyloid deposition were quantified using standard uptake value ratios and compared at a voxelwise level, controlling for age. PCA patients [median age-at-onset, 59 (51 to 61) years] were younger at symptom onset than similarly staged individuals with amnestic AD [75 (60 to 85) years] or CN controls [73 (61 to 90) years; P=0.002]. Flortaucipir uptake was higher in individuals with early-stage symptomatic PCA versus those with early-stage amnestic AD or CN controls, and greatest in posterior regions. Regional elevations in florbetapir were observed in areas of greatest tau deposition in PCA patients. Flortaucipir uptake distinguished individuals with PCA and amnestic AD dementia early in the symptomatic course. The posterior brain regions appear to be uniquely vulnerable to tau deposition in PCA, aligning with clinical deficits that define this disease subtype.

[Working memory for music in patients with mild cognitive impairment and early stage Alzheimer's disease].

PubMed

Kerer, Manuela; Marksteiner, Josef; Hinterhuber, Hartmann; Mazzola, Guerino; Kemmler, Georg; Bliem, Harald R; Weiss, Elisabeth M

2013-01-01

A variety of studies demonstrated that some forms of memory for music are spared in dementia, but only few studies have investigated patients with early stages of dementia. In this pilot-study we tested working memory for music in patients with mild cognitive impairment (MCI) and early stage Alzheimer's disease (AD) with a newly created test. The test probed working memory using 7 gradually elongated tone-lines and 6 chords which were each followed by 3 similar items and 1 identical item. The participants of the study, namely 10 patients with MCI, 10 patients with early stage AD and 23 healthy subjects were instructed to select the identical tone-line or chord. Subjects with MCI and early AD showed significantly reduced performance than controls in most of the presented tasks. In recognizing chords MCI- participants surprisingly showed an unimpaired performance. The gradual increase of the impairment during the preclinical phase of AD seems to spare this special ability in MCI.

Measuring and Modeling the Effects of Alternate Post-Fire Successional Trajectories on Boreal Forest Carbon Dynamics

NASA Astrophysics Data System (ADS)

Loranty, M. M.; Goetz, S. J.; Mack, M. C.; Alexander, H. D.; Beck, P. S.

2011-12-01

High latitude ecosystems are experiencing amplified climate warming, and recent evidence suggests concurrent intensification of fire disturbance regimes. In central Alaskan boreal forests, severe burns consume more of the soil organic layer, resulting in increased establishment of deciduous seedlings and altered post-fire stand composition with increased deciduous dominance. Quantifying differences in ecosystem carbon (C) dynamics between forest successional trajectories in response to burn severity is essential for understanding potential changes in regional or global feedbacks between boreal forests and climate. We used the Biome BioGeochemical Cycling model (Biome-BGC) to quantify differences in C stocks and fluxes associated with alternate post-fire successional trajectories related to fire severity. A version of Biome-BGC that allows alternate competing vegetation types was calibrated against a series of aboveground biomass observations from chronosequences of stands with differing post-fire successional trajectories characterized by the proportion of deciduous biomass. The model was able to reproduce observed patterns of biomass accumulation after fire, with stands dominated by deciduous species sequestering more C at a faster rate than stands dominated by conifers. Modeled C fluxes suggest that stands dominated by deciduous species are a stronger sink of atmospheric C soon after disturbance than coniferous stands. These results agree with the few available C flux observations. We use a historic database in conjunction with a map of deciduous canopy cover to explore the consequences of ongoing and potential future changes in the fire regime on central Alaskan C balance.

Involvement of Clostridium botulinum ATCC 3502 Sigma Factor K in Early-Stage Sporulation

PubMed Central

Kirk, David G.; Dahlsten, Elias; Zhang, Zhen; Korkeala, Hannu

2012-01-01

A key survival mechanism of Clostridium botulinum, the notorious neurotoxic food pathogen, is the ability to form heat-resistant spores. While the genetic mechanisms of sporulation are well understood in the model organism Bacillus subtilis, nothing is known about these mechanisms in C. botulinum. Using the ClosTron gene-knockout tool, sigK, encoding late-stage (stage IV) sporulation sigma factor K in B. subtilis, was disrupted in C. botulinum ATCC 3502 to produce two different mutants with distinct insertion sites and orientations. Both mutants were unable to form spores, and their elongated cell morphology suggested that the sporulation pathway was blocked at an early stage. In contrast, sigK-complemented mutants sporulated successfully. Quantitative real-time PCR analysis of sigK in the parent strain revealed expression at the late log growth phase in the parent strain. Analysis of spo0A, encoding the sporulation master switch, in the sigK mutant and the parent showed significantly reduced relative levels of spo0A expression in the sigK mutant compared to the parent strain. Similarly, sigF showed significantly lower relative transcription levels in the sigK mutant than the parent strain, suggesting that the sporulation pathway was blocked in the sigK mutant at an early stage. We conclude that σK is essential for early-stage sporulation in C. botulinum ATCC 3502, rather than being involved in late-stage sporulation, as reported for the sporulation model organism B. subtilis. Understanding the sporulation mechanism of C. botulinum provides keys to control the public health risks that the spores of this dangerous pathogen cause through foods. PMID:22544236

Involvement of Clostridium botulinum ATCC 3502 sigma factor K in early-stage sporulation.

PubMed

Kirk, David G; Dahlsten, Elias; Zhang, Zhen; Korkeala, Hannu; Lindström, Miia

2012-07-01

A key survival mechanism of Clostridium botulinum, the notorious neurotoxic food pathogen, is the ability to form heat-resistant spores. While the genetic mechanisms of sporulation are well understood in the model organism Bacillus subtilis, nothing is known about these mechanisms in C. botulinum. Using the ClosTron gene-knockout tool, sigK, encoding late-stage (stage IV) sporulation sigma factor K in B. subtilis, was disrupted in C. botulinum ATCC 3502 to produce two different mutants with distinct insertion sites and orientations. Both mutants were unable to form spores, and their elongated cell morphology suggested that the sporulation pathway was blocked at an early stage. In contrast, sigK-complemented mutants sporulated successfully. Quantitative real-time PCR analysis of sigK in the parent strain revealed expression at the late log growth phase in the parent strain. Analysis of spo0A, encoding the sporulation master switch, in the sigK mutant and the parent showed significantly reduced relative levels of spo0A expression in the sigK mutant compared to the parent strain. Similarly, sigF showed significantly lower relative transcription levels in the sigK mutant than the parent strain, suggesting that the sporulation pathway was blocked in the sigK mutant at an early stage. We conclude that σ(K) is essential for early-stage sporulation in C. botulinum ATCC 3502, rather than being involved in late-stage sporulation, as reported for the sporulation model organism B. subtilis. Understanding the sporulation mechanism of C. botulinum provides keys to control the public health risks that the spores of this dangerous pathogen cause through foods.

Tropical forest biomass and successional age class relationships to a vegetation index derived from Landsat TM data

NASA Technical Reports Server (NTRS)

Sader, Steven A.; Waide, Robert B.; Lawrence, William T.; Joyce, Armond T.

1989-01-01

Forest stand structure and biomass data were collected using conventional forest inventory techniques in tropical, subtropical, and warm temperate forest biomes. The feasibility of detecting tropical forest successional age class and total biomass differences using Landsat-Thematic mapper (TM) data, was evaluated. The Normalized Difference Vegetation Index (NDVI) calculated from Landsat-TM data were not significantly correlated with forest regeneration age classes in the mountain terrain of the Luquillo Experimental Forest, Puerto Rico. The low sun angle and shadows cast on steep north and west facing slopes reduced spectral reflectance values recorded by TM orbital altitude. The NDVI, calculated from low altitude aircraft scanner data, was significatly correlated with forest age classes. However, analysis of variance suggested that NDVI differences were not detectable for successional forests older than approximately 15-20 years. Also, biomass differences in young successional tropical forest were not detectable using the NDVI. The vegetation index does not appear to be a good predictor of stand structure variables (e.g., height, diameter of main stem) or total biomass in uneven age, mixed broadleaf forest. Good correlation between the vegetation index and low biomass in even age pine plantations were achieved for a warm temperate study site. The implications of the study for the use of NDVI for forest structure and biomass estimation are discussed.

Successional and seasonal variations in soil and litter microbial community structure and function during tropical postagricultural forest regeneration: a multiyear study.

PubMed

Smith, A Peyton; Marín-Spiotta, Erika; Balser, Teri

2015-09-01

Soil microorganisms regulate fundamental biochemical processes in plant litter decomposition and soil organic matter (SOM) transformations. Understanding how microbial communities respond to changes in vegetation is critical for improving predictions of how land-cover change affects belowground carbon storage and nutrient availability. We measured intra- and interannual variability in soil and forest litter microbial community composition and activity via phospholipid fatty acid analysis (PLFA) and extracellular enzyme activity across a well-replicated, long-term chronosequence of secondary forests growing on abandoned pastures in the wet subtropical forest life zone of Puerto Rico. Microbial community PLFA structure differed between young secondary forests and older secondary and primary forests, following successional shifts in tree species composition. These successional patterns held across seasons, but the microbial groups driving these patterns differed over time. Microbial community composition from the forest litter differed greatly from those in the soil, but did not show the same successional trends. Extracellular enzyme activity did not differ with forest succession, but varied by season with greater rates of potential activity in the dry seasons. We found few robust significant relationships among microbial community parameters and soil pH, moisture, carbon, and nitrogen concentrations. Observed inter- and intrannual variability in microbial community structure and activity reveal the importance of a multiple, temporal sampling strategy when investigating microbial community dynamics with land-use change. Successional control over microbial composition with forest recovery suggests strong links between above and belowground communities. © 2015 John Wiley & Sons Ltd.

High-throughput sequencing of the T cell receptor β gene identifies aggressive early-stage mycosis fungoides.

PubMed

de Masson, Adele; O'Malley, John T; Elco, Christopher P; Garcia, Sarah S; Divito, Sherrie J; Lowry, Elizabeth L; Tawa, Marianne; Fisher, David C; Devlin, Phillip M; Teague, Jessica E; Leboeuf, Nicole R; Kirsch, Ilan R; Robins, Harlan; Clark, Rachael A; Kupper, Thomas S

2018-05-09

Mycosis fungoides (MF), the most common cutaneous T cell lymphoma (CTCL) is a malignancy of skin-tropic memory T cells. Most MF cases present as early stage (stage I A/B, limited to the skin), and these patients typically have a chronic, indolent clinical course. However, a small subset of early-stage cases develop progressive and fatal disease. Because outcomes can be so different, early identification of this high-risk population is an urgent unmet clinical need. We evaluated the use of next-generation high-throughput DNA sequencing of the T cell receptor β gene ( TCRB ) in lesional skin biopsies to predict progression and survival in a discovery cohort of 208 patients with CTCL (177 with MF) from a 15-year longitudinal observational clinical study. We compared these data to the results in an independent validation cohort of 101 CTCL patients (87 with MF). The tumor clone frequency (TCF) in lesional skin, measured by high-throughput sequencing of the TCRB gene, was an independent prognostic factor of both progression-free and overall survival in patients with CTCL and MF in particular. In early-stage patients, a TCF of >25% in the skin was a stronger predictor of progression than any other established prognostic factor (stage IB versus IA, presence of plaques, high blood lactate dehydrogenase concentration, large-cell transformation, or age). The TCF therefore may accurately predict disease progression in early-stage MF. Early identification of patients at high risk for progression could help identify candidates who may benefit from allogeneic hematopoietic stem cell transplantation before their disease becomes treatment-refractory. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Falls and Fall Prevention in Older Adults With Early-Stage Dementia: An Integrative Review.

PubMed

Lach, Helen W; Harrison, Barbara E; Phongphanngam, Sutthida

2017-05-01

Older adults with mild cognitive impairment (MCI) and early-stage dementia have an increased risk of falling, with risks to their health and quality of life. The purpose of the current integrative review was to evaluate evidence on fall risk and fall prevention in this population. Studies were included if they examined falls or fall risk factors in older adults with MCI or early-stage dementia, or reported interventions in this population; 40 studies met criteria. Evidence supports the increased risk of falls in individuals even in the early stages of dementia or MCI, and changes in gait, balance, and fear of falling that may be related to this increased fall risk. Interventions included exercise and multifactorial interventions that demonstrated some potential to reduce falls in this population. Few studies had strong designs to provide evidence for recommendations. Further study in this area is warranted. [Res Gerontol Nurs. 2017; 10(03):139-148.]. Copyright 2016, SLACK Incorporated.

Collaboration with Pharma Will Introduce Nanotechnologies in Early Stage Drug Development | Poster

Cancer.gov

The Frederick National Lab has begun to assist several major pharmaceutical companies in adopting nanotechnologies in early stage drug development, when the approach is most efficient and cost-effective.

Axillary radiotherapy in conservative surgery for early-stage breast cancer (stage I and II).

PubMed

García Novoa, Alejandra; Acea Nebril, Benigno; Díaz, Inma; Builes Ramírez, Sergio; Varela, Cristina; Cereijo, Carmen; Mosquera Oses, Joaquín; López Calviño, Beatriz; Seoane Pillado, María Teresa

2016-01-01

Several clinical studies analyze axillary treatment in women with early-stage breast cancer because of changes in the indication for axillary lymph node dissection. The aim of the study is to analyze the impact of axillary radiotherapy in disease-free and overall survival in women with early breast cancer treated with lumpectomy. Retrospective study in women with initial stages of breast carcinoma treated by lumpectomy. A comparative analysis of high-risk women with axillary lymph node involvement who received axillary radiotherapy with the group of women with low risk without radiotherapy was performed. Logistic regression was used to determine factors influencing survival and lymphedema onset. A total of 541 women were included in the study: 384 patients (71%) without axillary lymph node involvement and 157 women (29%) with 1-3 axillary lymph node involvement. Patients with axillary radiotherapy had a higher number of metastatic lymph node compared to non-irradiated (1.6±0.7 vs. 1.4±0.6, P=.02). The group of women with axillary lymph node involvement and radiotherapy showed an overall and disease-free survival at 10 years similar to that obtained in patients without irradiation (89.7% and 77.2%, respectively). 3 lymph nodes involved multiplied by more than 7 times the risk of death (HR=7.20; 95% CI: 1.36 to 38.12). The multivariate analysis showed axillary lymph node dissection as the only variable associated with the development of lymphedema. The incidence of axillary relapse on stage I and II breast cancer is rare. In these patients axillary radiotherapy does not improve overall survival, but contributes to regional control in those patients with risk factors. Copyright © 2016 AEC. Publicado por Elsevier España, S.L.U. All rights reserved.

A case of urinary retention in the early stages of herpes simplex virus type-1 encephalitis.

PubMed

Fukuoka, Takuya; Nakazato, Yoshihiko; Miyake, Akifumi; Tamura, Naotoshi; Araki, Nobuo; Yamamoto, Toshimasa

2017-06-01

A 70-year-old man developed urinary retention in the early stages of herpes simplex virus (HSV) type-1 encephalitis. A nerve conduction study suggested latent myeloradiculitis. This is the first report of human herpes simplex virus-1 encephalitis followed by urinary retention at early stage from the onset like the Elsberg syndrome. Although relatively few similar cases have been reported, we consider that urinary retention is common in HSV-1 encephalitis, in which disturbances of consciousness usually require bladder catheterization from the onset. We further emphasize that urinary retention may occasionally occur in early stages of HSV-1 encephalitis, with a significant possibility of recovery. Copyright © 2017. Published by Elsevier B.V.

Structural neuroimaging across early-stage psychosis: Aberrations in neurobiological trajectories and implications for the staging model.

PubMed

Bartholomeusz, Cali F; Cropley, Vanessa L; Wannan, Cassandra; Di Biase, Maria; McGorry, Patrick D; Pantelis, Christos

2017-05-01

This review critically examines the structural neuroimaging evidence in psychotic illness, with a focus on longitudinal imaging across the first-episode psychosis and ultra-high-risk of psychosis illness stages. A thorough search of the literature involving specifically longitudinal neuroimaging in early illness stages of psychosis was conducted. The evidence supporting abnormalities in brain morphology and altered neurodevelopmental trajectories is discussed in the context of a clinical staging model. In general, grey matter (and, to a lesser extent, white matter) declines across multiple frontal, temporal (especially superior regions), insular and parietal regions during the first episode of psychosis, which has a steeper trajectory than that of age-matched healthy counterparts. Although the ultra-high-risk of psychosis literature is considerably mixed, evidence indicates that certain volumetric structural aberrations predate psychotic illness onset (e.g. prefrontal cortex thinning), while other abnormalities present in ultra-high-risk of psychosis populations are potentially non-psychosis-specific (e.g. hippocampal volume reductions). We highlight the advantages of longitudinal designs, discuss the implications such studies have on clinical staging and provide directions for future research.

Grazing effects on aboveground primary production and root biomass of early-seral, mid-seral, and undisturbed semiarid grassland

USGS Publications Warehouse

Milchunas, D.G.; Vandever, M.W.

2013-01-01

Annual/perennial and tall/short plant species differentially dominate early to late successional shortgrass steppe communities. Plant species can have different ratios of above-/below-ground biomass distributions and this can be modified by precipitation and grazing. We compared grazing effects on aboveground production and root biomass in early- and mid-seral fields and undisturbed shortgrass steppe. Production averaged across four years and grazed and ungrazed treatments were 246, 134, and 102 g m−2 yr−1 for the early-, mid-seral, and native sites, respectively, while root biomass averaged 358, 560, and 981 g m−2, respectively. Early- and mid-seral communities provided complimentary forage supplies but at the cost of root biomass. Grazing increased, decreased, or had no effect on aboveground production in early-, mid-seral, and native communities, and had no effect on roots in any. Grazing had some negative effects on early spring forage species, but not in the annual dominated early-seral community. Dominant species increased with grazing in native communities with a long evolutionary history of grazing by large herbivores, but had no effects on the same species in mid-seral communities. Effects of grazing in native communities in a region cannot necessarily be used to predict effects at other seral stages.

Frustration Sculpts the Early Stages of Protein Folding.

PubMed

Di Silvio, Eva; Brunori, Maurizio; Gianni, Stefano

2015-09-07

The funneled energy landscape theory implies that protein structures are minimally frustrated. Yet, because of the divergent demands between folding and function, regions of frustrated patterns are present at the active site of proteins. To understand the effects of such local frustration in dictating the energy landscape of proteins, here we compare the folding mechanisms of the two alternative spliced forms of a PDZ domain (PDZ2 and PDZ2as) that share a nearly identical sequence and structure, while displaying different frustration patterns. The analysis, based on the kinetic characterization of a large number of site-directed mutants, reveals that although the late stages for folding are very robust and biased by native topology, the early stages are more malleable and dominated by local frustration. The results are briefly discussed in the context of the energy-landscape theory. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Treatment of early-stage Hodgkin lymphoma.

PubMed

Engert, Andreas; Raemaekers, John

2016-07-01

Hodgkin lymphoma (HL) has become one of the best curable malignancies today. This is particularly true for patients with early-stage disease. Today, most patients in this risk group are treated with a combination of chemotherapy followed by small-field radiotherapy. More recent clinical trials such as the German Hodgkin Study Group (GHSG) HD10 study demonstrated, that even two cycles of ABVD followed by 20 Gy involved-field radiation therapy (IF-RT) are sufficient and result in more than 90% of patients being cured. The current treatment for early unfavorable patients is either four cycles of ABVD plus 30 Gy IF-RT or two cycles of BEACOPPbaseline followed by two cycles of ABVD plus IF-RT. Here, the European Organization for Research and Treatment of Cancer (EORTC) demonstrated that in positron emission tomography (PET)-positive patients after two cycles of ABVD, treatment switched to two cycles of BEACOPPbaseline plus radiotherapy results in significantly improved outcomes. Other aspects including attempts to further reduce intensity of treatment will be discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

Subcortical grey matter changes in untreated, early stage Parkinson's disease without dementia.

PubMed

Lee, Hye Mi; Kwon, Kyum-Yil; Kim, Min-Jik; Jang, Ji-Wan; Suh, Sang-Il; Koh, Seong-Beom; Kim, Ji Hyun

2014-06-01

Previous MRI studies have investigated cortical or subcortical grey matter changes in patients with Parkinson's disease (PD), yielding inconsistent findings between the studies. We therefore sought to determine whether focal cortical or subcortical grey matter changes may be present from the early disease stage. We recruited 49 untreated, early stage PD patients without dementia and 53 control subjects. Voxel-based morphometry was used to evaluate cortical grey matter changes, and automated volumetry and shape analysis were used to assess volume changes and shape deformation of the subcortical grey matter structures, respectively. Voxel-based morphometry showed neither reductions nor increases in grey matter volume in patients compared to controls. Compared to controls, PD patients had significant reductions in adjusted volumes of putamen, nucleus accumbens, and hippocampus (corrected p < 0.05). Vertex-based shape analysis showed regionally contracted area on the posterolateral and ventromedial putamen bilaterally in PD patients (corrected p < 0.05). No correlations were found between cortical and subcortical grey matter and clinical variables representing disease duration and severity. Our results suggest that untreated, early stage PD without dementia is associated with volume reduction and shape deformation of subcortical grey matter, but not with cortical grey matter reduction. Our findings of structural changes in the posterolateral putamen and ventromedial putamen/nucleus accumbens could provide neuroanatomical basis for the involvement of motor and limbic striatum, further implicating motor and non-motor symptoms in PD, respectively. Early hippocampal involvement might be related to the risk for developing dementia in PD patients. Copyright © 2014 Elsevier Ltd. All rights reserved.

Association of Marital Status With T Stage at Presentation and Management of Early-Stage Melanoma.

PubMed

Sharon, Cimarron E; Sinnamon, Andrew J; Ming, Michael E; Chu, Emily Y; Fraker, Douglas L; Karakousis, Giorgos C

2018-05-01

Early detection of melanoma is associated with improved patient outcomes. Data suggest that spouses or partners may facilitate detection of melanoma before the onset of regional and distant metastases. Less well known is the influence of marital status on the detection of early clinically localized melanoma. To evaluate the association between marital status and T stage at the time of presentation with early-stage melanoma and the decision for sentinel lymph node biopsy (SLNB) in appropriate patients. This retrospective, population-based study used the Surveillance, Epidemiology, and End Results database of 18 population-based registered cancer institutes. Patients with cutaneous melanoma who were at least 18 years of age and without evidence of regional or distant metastases and presented from January 1, 2010, through December 31, 2014, were identified for the study. Data were analyzed from September 27 to December 5, 2017. Marital status, categorized as married, never married, divorced, or widowed. Clinical T stage at presentation and performance of SLNB for lesions with Breslow thickness greater than 1 mm. A total of 52 063 patients were identified (58.8% men and 41.2% women; median age, 64 years; interquartile range, 52-75 years). Among married patients, 16 603 (45.7%) presented with T1a disease, compared with 3253 never married patients (43.0%), 1422 divorced patients (39.0%), and 1461 widowed patients (32.2%) (P < .001). Conversely, 428 widowed patients (9.4%) presented with T4b disease compared with 1188 married patients (3.3%) (P < .001). The association between marital status and higher T stage at presentation remained significant among never married (odds ratio [OR], 1.32; 95% CI, 1.26-1.39; P < .001), divorced (OR, 1.38; 95% CI, 1.30-1.47; P < .001), and widowed (OR, 1.70; 95% CI, 1.60-1.81; P < .001) patients after adjustment for various socioeconomic and patient factors. Independent of T stage and other patient factors, married

Selection is stronger in early-versus-late stages of divergence in a Neotropical livebearing fish.

PubMed

Ingley, Spencer J; Johnson, Jerald B

2016-03-01

How selection acts to drive trait evolution at different stages of divergence is of fundamental importance in our understanding of the origins of biodiversity. Yet, most studies have focused on a single point along an evolutionary trajectory. Here, we provide a case study evaluating the strength of divergent selection acting on life-history traits at early-versus-late stages of divergence in Brachyrhaphis fishes. We find that the difference in selection is stronger in the early-diverged population than the late-diverged population, and that trait differences acquired early are maintained over time. © 2016 The Author(s).

Restricted T cell receptor repertoire in CLL-like monoclonal B cell lymphocytosis and early stage CLL.

PubMed

Blanco, Gonzalo; Vardi, Anna; Puiggros, Anna; Gómez-Llonín, Andrea; Muro, Manuel; Rodríguez-Rivera, María; Stalika, Evangelia; Abella, Eugenia; Gimeno, Eva; López-Sánchez, Manuela; Senín, Alicia; Calvo, Xavier; Abrisqueta, Pau; Bosch, Francesc; Ferrer, Ana; Stamatopoulos, Kostas; Espinet, Blanca

2018-01-01

Analysis of the T cell receptor (TR) repertoire of chronic lymphocytic leukemia-like monoclonal B cell lymphocytosis (CLL-like MBL) and early stage CLL is relevant for understanding the dynamic interaction of expanded B cell clones with bystander T cells. Here we profiled the T cell receptor β chain (TRB) repertoire of the CD4 + and CD8 + T cell fractions from 16 CLL-like MBL and 13 untreated, Binet stage A/Rai stage 0 CLL patients using subcloning analysis followed by Sanger sequencing. The T cell subpopulations of both MBL and early stage CLL harbored restricted TRB gene repertoire, with CD4 + T cell clonal expansions whose frequency followed the numerical increase of clonal B cells. Longitudinal analysis in MBL cases revealed clonal persistence, alluding to persistent antigen stimulation. In addition, the identification of shared clonotypes among different MBL/early stage CLL cases pointed towards selection of the T cell clones by common antigenic elements. T cell clonotypes previously described in viral infections and immune disorders were also detected. Altogether, our findings evidence that antigen-mediated TR restriction occurs early in clonal evolution leading to CLL and may further increase together with B cell clonal expansion, possibly suggesting that the T cell selecting antigens are tumor-related.

Stimuli-disassembling gold nanoclusters for diagnosis of early stage oral cancer by optical coherence tomography

NASA Astrophysics Data System (ADS)

Kim, Chang Soo; Ingato, Dominique; Wilder-Smith, Petra; Chen, Zhongping; Kwon, Young Jik

2018-01-01

A key design consideration in developing contrast agents is obtaining distinct, multiple signal changes in diseased tissue. Plasmonic gold nanoparticles (Au NPs) have been developed as contrast agents due to their strong surface plasmon resonance (SPR). This study aims to demonstrate that stimuli-responsive plasmonic Au nanoclusters (Au NCs) can be used as a contrast agent for optical coherence tomography (OCT) in detecting early-stage cancer. Au NPs were clustered via acid-cleavable linkers to synthesize Au NCs that disassemble under mildly acidic conditions into individual Au NPs, simultaneously diminishing SPR effect (quantified by scattering intensity) and increasing Brownian motion (quantified by Doppler variance). The acid-triggered morphological and accompanying optico-physical property changes of the acid-disassembling Au NCs were confirmed by TEM, DLS, UV/Vis, and OCT. Stimuli-responsive Au NCs were applied in a hamster check pouch model carrying early-stage squamous carcinoma tissue. The tissue was visualized by OCT imaging, which showed reduced scattering intensity and increased Doppler variance in the dysplastic tissue. This study demonstrates the promise of diagnosing early-stage cancer using molecularly programmable, inorganic nanomaterial-based contrast agents that are capable of generating multiple, stimuli-triggered diagnostic signals in early-stage cancer.[Figure not available: see fulltext.

No Value for Routine Chest Radiography in the Work-Up of Early Stage Cervical Cancer Patients

PubMed Central

Hoogendam, Jacob P.; Zweemer, Ronald P.; Verkooijen, Helena M.; de Jong, Pim A.; van den Bosch, Maurice A. A. J.; Verheijen, René H. M.; Veldhuis, Wouter B.

2015-01-01

Aim Evidence supporting the recommendation to include chest radiography in the work-up of all cervical cancer patients is limited. We investigated the diagnostic value of routine chest radiography in cervical cancer staging. Methods All consecutive cervical cancer patients who presented at our tertiary referral center in the Netherlands (January 2006 – September 2013), and for whom ≥6 months follow-up was available, were included. As part of the staging procedure, patients underwent a routine two-directional digital chest radiograph. Findings were compared to a composite reference standard consisting of all imaging studies and histology obtained during the 6 months following radiography. Results Of the 402 women who presented with cervical cancer, 288 (71.6%) underwent chest radiography and had ≥6 months follow-up. Early clinical stage (I/II) cervical cancer was present in 244/288 (84.7%) women, while 44 (15.3%) presented with advanced disease (stage III/IV). The chest radiograph of 1 woman – with advanced pre-radiograph stage (IVA) disease – showed findings consistent with pulmonary metastases. Radiographs of 7 other women – 4 early, 3 advanced stage disease – were suspicious for pulmonary metastases which was confirmed by additional imaging in only 1 woman (with pre-radiograph advanced stage (IIIB) disease) and excluded in 6 cases, including all women with early stage disease. In none of the 288 women were thoracic skeletal metastases identified on imaging or during 6 months follow up. Radiography was unremarkable in 76.4% of the study population, and showed findings unrelated to the cervical carcinoma in 21.2%. Conclusion Routine chest radiography was of no value for any of the early stage cervical cancer patients presenting at our tertiary center over a period of 7.7 years. PMID:26135733

No Value for Routine Chest Radiography in the Work-Up of Early Stage Cervical Cancer Patients.

PubMed

Hoogendam, Jacob P; Zweemer, Ronald P; Verkooijen, Helena M; de Jong, Pim A; van den Bosch, Maurice A A J; Verheijen, René H M; Veldhuis, Wouter B

2015-01-01

Evidence supporting the recommendation to include chest radiography in the work-up of all cervical cancer patients is limited. We investigated the diagnostic value of routine chest radiography in cervical cancer staging. All consecutive cervical cancer patients who presented at our tertiary referral center in the Netherlands (January 2006 - September 2013), and for whom ≥6 months follow-up was available, were included. As part of the staging procedure, patients underwent a routine two-directional digital chest radiograph. Findings were compared to a composite reference standard consisting of all imaging studies and histology obtained during the 6 months following radiography. Of the 402 women who presented with cervical cancer, 288 (71.6%) underwent chest radiography and had ≥6 months follow-up. Early clinical stage (I/II) cervical cancer was present in 244/288 (84.7%) women, while 44 (15.3%) presented with advanced disease (stage III/IV). The chest radiograph of 1 woman - with advanced pre-radiograph stage (IVA) disease - showed findings consistent with pulmonary metastases. Radiographs of 7 other women - 4 early, 3 advanced stage disease - were suspicious for pulmonary metastases which was confirmed by additional imaging in only 1 woman (with pre-radiograph advanced stage (IIIB) disease) and excluded in 6 cases, including all women with early stage disease. In none of the 288 women were thoracic skeletal metastases identified on imaging or during 6 months follow up. Radiography was unremarkable in 76.4% of the study population, and showed findings unrelated to the cervical carcinoma in 21.2%. Routine chest radiography was of no value for any of the early stage cervical cancer patients presenting at our tertiary center over a period of 7.7 years.

40 CFR 797.1600 - Fish early life stage toxicity test.

Code of Federal Regulations, 2013 CFR

2013-07-01

... dilution water or the test solution. (4) “Control” an exposure of test organisms to dilution water only or... (treatment) concentrations of a test substance and one control are required to conduct an early life stage... trays or cups for each test concentration and control (i.e., 30 per embryo cup with 2 replicates); (C...

40 CFR 797.1600 - Fish early life stage toxicity test.

Code of Federal Regulations, 2010 CFR

2010-07-01

... dilution water or the test solution. (4) “Control” an exposure of test organisms to dilution water only or... (treatment) concentrations of a test substance and one control are required to conduct an early life stage... trays or cups for each test concentration and control (i.e., 30 per embryo cup with 2 replicates); (C...

40 CFR 797.1600 - Fish early life stage toxicity test.

Code of Federal Regulations, 2012 CFR

2012-07-01

... dilution water or the test solution. (4) “Control” an exposure of test organisms to dilution water only or... (treatment) concentrations of a test substance and one control are required to conduct an early life stage... trays or cups for each test concentration and control (i.e., 30 per embryo cup with 2 replicates); (C...

The importance of disturbance versus physiography in defining vegetation composition and predicting possible successional trajectories

Treesearch

Cynthia D. Huebner; David W. McGill

2018-01-01

Regional (climate/soils) and local (aspect) physiography determine plant community composition. However, changes in initial floristic composition after a disturbance may be severe enough to alter the successional trajectory predicted by physiography. We addressed the question of which is more important, disturbance or physiography, in determining vegetation composition...

Loss of corticospinal tract integrity in early MS disease stages

PubMed Central

Neumann, Jens; Kaufmann, Jörn; Heidel, Jan; Stadler, Erhard; Sweeney-Reed, Catherine; Sailer, Michael; Schreiber, Stefanie

2017-01-01

Objective: We investigated corticospinal tract (CST) integrity in the absence of white matter (WM) lesions using diffusion tensor imaging (DTI) in early MS disease stages. Methods: Our study comprised 19 patients with clinically isolated syndrome (CIS), 11 patients with relapsing-remitting MS (RRMS), and 32 age- and sex-matched healthy controls, for whom MRI measures of CST integrity (fractional anisotropy [FA], mean diffusivity [MD]), T1- and T2-based lesion load, and brain volumes were available. The mean (SD) disease duration was 3.5 (2.1) months, and disability score was low (median Expanded Disability Status Scale 1.5) at the time of the study. Results: Patients with CIS and RRMS had significantly lower CST FA and higher CST MD values compared with controls. These findings were present, irrespective of whether WM lesions affected the CST. However, no group differences in the overall gray or WM volume were identified. Conclusions: In early MS disease stages, CST integrity is already affected in the absence of WM lesions or brain atrophy. PMID:28959706

Urinary Biomarkers at Early ADPKD Disease Stage

PubMed Central

Petzold, Katja; Poster, Diane; Krauer, Fabienne; Spanaus, Katharina; Andreisek, Gustav; Nguyen-Kim, Thi Dan Linh; Pavik, Ivana; Ho, Thien Anh; Serra, Andreas L.; Rotar, Laura

2015-01-01

Background Autosomal dominant polycystic kidney disease (ADPKD) is characterized by a decline in renal function at late disease stage when the majority of functional renal parenchyma is replaced by cystic tissue. Thus, kidney function, assessed by estimated glomerular filtration rate (eGFR) does not well represent disease burden in early disease. Here, we investigated various urinary markers for tubular injury and their association with disease burden in ADPKD patients at early disease course. Methods ADPKD patients between 18 and 40 years with an eGFR greater or equal to 70 ml per min per 1.73m2 were eligible for this cross-sectional study. Urinary Neutrophil Gelatinase-Associated Lipocalin (NGAL), Kidney Injury Molecule-1 (KIM-1), and Uromodulin (UMOD) were investigated by Enzyme-Linked Immunosorbent Assay. Clara Cell Protein 16 (CC16) was investigated by Latex Immuno Assay. Cryoscopy was performed to assess urine osmolality and Urinary Albumin-to-Creatinine Ratio (UACR) was calculated. The association and the predictive properties of the markers on eGFR and height adjusted total kidney volume (htTKV) was evaluated using multiple regression analysis, incorporating different control variables for adjustment. Internal bootstrapping validated the obtained results. Results In 139 ADPKD patients (age 31 ±7 years, mean eGFR of 93 ± 19 ml per min per 1.73 m2) the total kidney volume was negatively correlated with eGFR and UMOD and positive associated with age, UACR, KIM-1 and urine osmolality after adjustment for possible confounders. Urine osmolality and htTKV were also associated with eGFR, whereas no association of CC16, NGAL and UMOD with eGFR or htTKV was found. Conclusion UACR and urinary KIM-1 are independently associated with kidney size but not with renal function in our study population. Urine osmolality was associated with eGFR and kidney volume following adjustment for multiple confounders. Despite statistical significance, the clinical value of our

Adjuvant therapy in early-stage non-small cell lung cancer.

PubMed

Serke, Monika

2010-01-01

Evidence clearly supports adjuvant chemotherapy following resection in patients with stage II or III non-small cell lung cancer (NSCLC). Based on 3 landmark studies, adjuvant chemotherapy has become standard in completely resected NSCLC stage II and IIIA. Survival benefit from adjuvant chemotherapy is estimated to be between 3% and 15%, depending on stage. Treatment should include 4 cycles of platinum-based combination chemotherapy. There is uncertainty about chemotherapy prescription in those patients with resected stage IB NSCLC, as the risk of recurrence is lower in early NSCLC and the magnitude of benefit of adjuvant therapy is proportional to the risk of relapse according to stage. Postoperative radiotherapy (PORT) should not be used for stage I or II NSCLC, and remains controversial in resected stage IIIA (N2) disease. All positive adjuvant trials have utilized a cisplatin-based regimen, usually in combination with vinorelbine, and this should be considered the standard approach. Prognostic factors to select patients who will benefit from adjuvant therapy in general or from platinum-based chemotherapy are under discussion, but not yet established. In future we hope to optimize treatment convenience for the patients by using other combinations with the hope of better efficacy results. Work is currently under way to identify prognostic factors which in future may help to identify patients who are most likely to benefit from chemotherapy. Copyright 2010 S. Karger AG, Basel.

PTT functional recovery in early stage II PTTD after tendon balancing and calcaneal lengthening osteotomy.

PubMed

Brilhault, Jean; Noël, Vincent

2012-10-01

The decision to offer surgery for Stage II posterior tibial tendon deficiency (PTTD) is a difficult one since orthotic treatment has been documented to be a viable alternative to surgery at this stage. Taking this into consideration we limited our treatment to bony realignment by a lengthening calcaneus Evans osteotomy and tendon balancing. The goal of the study was to clinically evaluate PTT functional recovery with this procedure. The patient population included 17 feet in 13 patients. Inclusion was limited to early Stage II PTTD flatfeet with grossly intact but deficient PTT. Deficiency was assessed by the lack of hindfoot inversion during single heel rise test. The surgical procedure included an Evans calcaneal opening wedge osteotomy with triceps surae and peroneus brevis tendon lengthening. PTT function at follow up was evaluated by an independent examiner. Evaluation was performed at an average of 4 (range, 2 to 6.3) years. One case presented postoperative subtalar pain that required subtalar fusion. Every foot could perform a single heel rise with 13 feet having active inversion of the hindfoot during elevation. The results of this study provide evidence of PTT functional recovery without augmentation in early Stage II. It challenges our understanding of early Stage II PTTD as well as the surgical guidelines recommending PTT augmentation at this specific stage.

Role of Chemotherapy and Targeted Therapy in Early-Stage Non-Small Cell Lung Cancer.

PubMed

Gadgeel, Shirish M

2017-01-01

On the basis of several randomized trials and meta-analyses, adjuvant chemotherapy is the accepted standard of care for certain patients with early-stage non-small cell lung cancer (NSCLC). Patients with stage II, IIIA, or large (≥ 4 cm) IB tumors are candidates for adjuvant chemotherapy. The survival improvement with adjuvant chemotherapy is approximately 5% at 5 years, though certain trials have suggested that it can be 8% to 10%. Neoadjuvant chemotherapy also has shown a survival advantage, though the volume of data with this approach is far less than that of adjuvant chemotherapy. The combination of cisplatin and vinorelbine is the most well-studied regimen, but current consensus is to use four cycles of any of the platinum-based chemotherapy regimens commonly used as front-line therapy for patients with advanced-stage NSCLC. Trials to define biomarkers that can predict benefit from adjuvant chemotherapy have not been successful, but results of other such trials are still awaited. On the basis of the benefit observed with targeted agents in patients with advanced-stage disease and driver genetic alterations in their tumors, ongoing trials are evaluating the utility of these targeted agents as adjuvant therapy. Similarly, clinical benefit observed with checkpoint inhibitors has prompted assessment of these drugs in patients with early-stage NSCLC. It is very likely, in the future, that factors other than the anatomy of the tumor will be used to select patients with early-stage NSCLC for systemic therapy and that the choice of systemic therapy will extend beyond platinum-based chemotherapy.

Treatment of Early-stage Extracranial Arteriovenous Malformations with Intralesional Interstitial Bleomycin Injection: A Pilot Study.

PubMed

Jin, Yunbo; Zou, Yun; Hua, Chen; Chen, Hui; Yang, Xi; Ma, Gang; Chang, Lei; Qiu, Yajing; Lyu, Dongze; Wang, Tianyou; Chang, Shih-Jen; Qiao, Congzhen; Luo, Chunfen; Tremp, Mathias; Lin, Xiaoxi

2018-04-01

Purpose To assess the efficacy and safety of intralesional interstitial bleomycin injection in the treatment of early-stage (Schobinger stage I or II) extracranial arteriovenous malformations (AVMs). Materials and Methods This prospective study involved 34 patients with early-stage AVMs, as defined by the Schobinger staging system. The patients received intralesional interstitial bleomycin injected at a maximum dose of 15 000 IU or 1000 IU per kilogram of body weight for children who weighed less than 15 kg per procedure for a total of 6 months (once every month). Therapeutic outcome was evaluated by the degree of devascularization at angiography and the clinical outcome 3 months after the last treatment. Further follow-up was evaluated based on further clinical outcome. Adverse events were recorded according to the Society of Interventional Radiology classification. Results Of the 34 patients with early-stage AVM, 32 (mean age, 20.5 years; 24 female [75%]) completed the study. The results showed that 27 (84.4%, 95% confidence interval [CI]: 71.1, 97.7) patients were responsive to bleomycin injection, including nine (28.1%) with a complete response. Four (12.5%) patients showed no response, and one (3.1%) patient experienced worsening 3 months after the last treatment. During further follow-up (mean follow-up time, 20.7 months; range, 5-28 months), the outcome remained stable in 31 (96.9%) of the 32 patients. A major complication, anaphylactic shock, was observed in one (3.1%, 95% CI: 0, 9.5) patient. Common minor complications included hyperpigmentation, nausea, pruritus, and bullae. Conclusion Intralesional interstitial bleomycin injection is a feasible approach for early-stage AVMs and yields safe and effective outcomes. © RSNA, 2017.

Detection of Apoptosis in Early Life Stages as a Tool to Evaluate Chemical Control of Invasive Species

DTIC Science & Technology

2007-08-01

ERDC/TN ANSRP-07-2 August 2007 Detection of Apoptosis in Early Life Stages as a Tool to Evaluate Chemical Control of Invasive Species by J...4. TITLE AND SUBTITLE Detection of Apoptosis in Early Life Stages as a Tool to Evaluate Chemical Control of Invasive Species 5a. CONTRACT NUMBER 5b...heralding apoptosis . Data analysis. An apoptotic index (API) was established by calculating the percentage of embryos in each life stage with

Ecosystem and decomposer effects on litter dynamics along an old field to old-growth forest successional gradient

EPA Science Inventory

Identifying the biotic (e.g. decomposers, vegetation) and abiotic (e.g. temperature, moisture) mechanisms controlling litter decomposition is key to understanding ecosystem function, especially where variation in ecosystem structure due to successional processes may alter the str...

"A palliative end-stage COPD patient does not exist": a qualitative study of barriers to and facilitators for early integration of palliative home care for end-stage COPD.

PubMed

Scheerens, Charlotte; Deliens, Luc; Van Belle, Simon; Joos, Guy; Pype, Peter; Chambaere, Kenneth

2018-06-20

Early integration of palliative home care (PHC) might positively affect people with chronic obstructive pulmonary disease (COPD). However, PHC as a holistic approach is not well integrated in clinical practice at the end-stage COPD. General practitioners (GPs) and community nurses (CNs) are highly involved in primary and home care and could provide valuable perspectives about barriers to and facilitators for early integrated PHC in end-stage COPD. Three focus groups were organised with GPs (n = 28) and four with CNs (n = 28), transcribed verbatim and comparatively analysed. Barriers were related to the unpredictability of COPD, a lack of disease insight and resistance towards care of the patient, lack of cooperation and experience with PHC for professional caregivers, lack of education about early integrated PHC, insufficient continuity of care from hospital to home, and lack of communication about PHC between professional caregivers and with end-stage COPD patients. Facilitators were the use of trigger moments for early integrating PHC, such as after a hospital admission or when an end-stage COPD patient becomes oxygen-dependent or housebound, positive attitudes towards PHC in informal caregivers, more focus on early integration of PHC in professional caregivers' education, implementing advance care planning in healthcare and PHC systems, and enhancing communication about care and PHC. The results provide insights for clinical practice and the development of key components for successful practice in a phase 0-2 Early Integration of PHC for end-stage COPD (EPIC) trial, such as improving care integration, patients' disease insight and training PHC nurses in care for end-stage COPD.

Assessments of plasma ghrelin levels in the early stages of parkinson's disease.

PubMed

Song, Ning; Wang, Weiwei; Jia, Fengjv; Du, Xixun; Xie, Anmu; He, Qing; Shen, Xiaoli; Zhang, Jing; Rogers, Jack T; Xie, Junxia; Jiang, Hong

2017-10-01

Gastrointestinal symptoms are early events in Parkinson's disease (PD). The gastrointestinal hormone ghrelin was neuroprotective in the nigrostriatal dopamine system. The objective of this study was to assess ghrelin levels in the early stages of PD. Plasma was collected in the fasting state in 291 PD patients in stages 1-3 and 303 age- and sex-matched healthy controls. Additional samples were taken in the glucose response test to assess nutrition-related ghrelin levels in 20 PD patients and 20 healthy controls. The enzyme-linked immunosorbent assay was used to measure total and active plasma ghrelin levels. We reported that total and active plasma ghrelin levels were decreased in PD, although there was no difference across progressive PD stages. Postprandial ghrelin suppression and preprandial peak responses were both attenuated in PD. Plasma ghrelin levels were decreased in PD; however, this event might be irrelevant to PD progression. Ghrelin responses to meals were also impaired in PD. © 2017 International Parkinson and Movement Disorder Society. © 2017 International Parkinson and Movement Disorder Society.

Practice Patterns and Long-Term Survival for Early-Stage Rectal Cancer

PubMed Central

Stitzenberg, Karyn B.; Sanoff, Hanna K.; Penn, Dolly C.; Meyers, Michael O.; Tepper, Joel E.

2013-01-01

Purpose Standard of care treatment for most stage I rectal cancers is total mesorectal excision (TME). Given the morbidity associated with TME, local excision (LE) for early-stage rectal cancer has been explored. This study examines practice patterns and overall survival (OS) for early-stage rectal cancer. Methods All patients in the National Cancer Data Base diagnosed with rectal cancer from 1998 to 2010 were initially included. Use of LE versus proctectomy and use of adjuvant radiation therapy were compared over time. Adjusted Cox proportional hazards models were used to compare OS based on treatment. Results LE was used to treat 46.5% of patients with T1 and 16.8% with T2 tumors. Use of LE increased steadily over time (P < .001). LE was most commonly used for women, black patients, very old patients, those without private health insurance, those with well-differentiated tumors, and those with T1 tumors. Proctectomy was associated with higher rates of tumor-free surgical margins compared with LE (95% v 76%; P < .001). Adjuvant radiation therapy use decreased over time independent of surgical procedure or T stage. For T2N0 disease, patients treated with LE alone had significantly poorer adjusted OS than those treated with proctectomy alone or multimodality therapy. Conclusion Guideline-concordant adoption of LE for treatment of low-risk stage I rectal cancer is increasing. However, use of LE is also increasing for higher-risk rectal cancers that do not meet guideline criteria for LE. Treatment with LE alone is associated with poorer long-term OS. Additional studies are warranted to understand the factors driving increased use of LE. PMID:24166526

Practice patterns and long-term survival for early-stage rectal cancer.

PubMed

Stitzenberg, Karyn B; Sanoff, Hanna K; Penn, Dolly C; Meyers, Michael O; Tepper, Joel E

2013-12-01

Standard of care treatment for most stage I rectal cancers is total mesorectal excision (TME). Given the morbidity associated with TME, local excision (LE) for early-stage rectal cancer has been explored. This study examines practice patterns and overall survival (OS) for early-stage rectal cancer. All patients in the National Cancer Data Base diagnosed with rectal cancer from 1998 to 2010 were initially included. Use of LE versus proctectomy and use of adjuvant radiation therapy were compared over time. Adjusted Cox proportional hazards models were used to compare OS based on treatment. LE was used to treat 46.5% of patients with T1 and 16.8% with T2 tumors. Use of LE increased steadily over time (P < .001). LE was most commonly used for women, black patients, very old patients, those without private health insurance, those with well-differentiated tumors, and those with T1 tumors. Proctectomy was associated with higher rates of tumor-free surgical margins compared with LE (95% v 76%; P < .001). Adjuvant radiation therapy use decreased over time independent of surgical procedure or T stage. For T2N0 disease, patients treated with LE alone had significantly poorer adjusted OS than those treated with proctectomy alone or multimodality therapy. Guideline-concordant adoption of LE for treatment of low-risk stage I rectal cancer is increasing. However, use of LE is also increasing for higher-risk rectal cancers that do not meet guideline criteria for LE. Treatment with LE alone is associated with poorer long-term OS. Additional studies are warranted to understand the factors driving increased use of LE.

Sleep Characteristics in Early Stages of Chronic Kidney Disease in the HypnoLaus Cohort

PubMed Central

Ogna, Adam; Forni Ogna, Valentina; Haba Rubio, José; Tobback, Nadia; Andries, Dana; Preisig, Martin; Tafti, Mehdi; Vollenweider, Peter; Waeber, Gerard; Marques-Vidal, Pedro; Heinzer, Raphaël

2016-01-01

Study Objectives: To evaluate the association between early stages of chronic kidney disease (CKD) and sleep disordered breathing (SDB), restless legs syndrome (RLS), and subjective and objective sleep quality (SQ). Methods: Cross-sectional analysis of a general population-based cohort (HypnoLaus). 1,760 adults (862 men, 898 women; age 59.3 (± 11.4) y) underwent complete polysomnography at home. Results: 8.2% of participants had mild CKD (stage 1–2, estimated glomerular filtration rate [eGFR] ≥ 60 mL/min/1.73 m2 with albuminuria) and 7.8% moderate CKD (stage 3, eGFR 30–60 mL/min/1.73 m2). 37.3% of our sample had moderate-to-severe SDB (apnea-hypopnea index [AHI] ≥ 15/h) and 15.3% had severe SDB (AHI ≥ 30/h). SDB prevalence was positively associated with CKD stages and negatively with eGFR. In multivariate analysis, age, male sex, and body mass index were independently associated with SDB (all P < 0.001), but kidney function was not. The prevalence of RLS was 17.5%, without difference between CKD stages. Periodic leg movements index (PLMI) was independently associated with CKD stages. Subjective and objective SQ decreased and the use of sleep medication was more frequent with declining kidney function. Older age, female sex, and the severity of SDB were the strongest predictors of poor SQ in multivariate regression analysis but CKD stage was also independently associated with reduced objective SQ. Conclusions: Patients with early stages of CKD have impaired SQ, use more hypnotic drugs, and have an increased prevalence of SDB and PLM. After controlling for confounders, objective SQ and PLMI were still independently associated with declining kidney function. Citation: Ogna A, Forni Ogna V, Haba Rubio J, Tobback N, Andries D, Preisig M, Tafti M, Vollenweider P, Waeber G, Marques-Vidal P, Heinzer R. Sleep characteristics in early stages of chronic kidney disease in the HypnoLaus cohort. SLEEP 2016;39(4):945–953. PMID:26715230

Do natural disturbances or the forestry practices that follow them convert forests to early-successional communities?

PubMed

Brewer, J Stephen; Bertz, Christine A; Cannon, Jeffery B; Chesser, Jason D; Maynard, Erynn E

2012-03-01

Stand-replacing natural disturbances in mature forests are traditionally seen as events that cause forests to revert to early stages of succession and maintain species diversity. In some cases, however, such transitions could be an artifact of salvage logging and may increase biotic homogenization. We present initial (two-year) results of a study of the effects of tornado damage and the combined effects of tornado damage and salvage logging on environmental conditions and ground cover plant communities in mixed oak-pine forests in north central Mississippi. Plots were established in salvage-logged areas, adjacent to plots established before the storm in unlogged areas, spanning a gradient of storm damage intensity. Vegetation change directly attributable to tornado damage was driven primarily by a reduction in canopy cover but was not consistent with a transition to an early stage of succession. Although we observed post-storm increases of several disturbance indicators (ruderals), we also observed significant increases in the abundance of a few species indicative of upland forests. Increases in flowering were just as likely to occur in species indicative of forests as in species indicative of open woodlands. Few species declined as a result of the tornado, resulting in a net increase in species richness. Ruderals were very abundant in salvage-logged areas, which contained significantly higher amounts of bare ground and greater variance in soil penetrability than did damaged areas that were not logged. In contrast to unlogged areas severely damaged by the tornado, most upland forest indicators were not abundant in logged areas. Several of the forest and open-woodland indicators that showed increased flowering in damaged areas were absent or sparse in logged areas. Species richness was lower in salvage-logged areas than in adjacent damaged areas but similar to that in undamaged areas. These results suggest that salvage logging prevented positive responses of several

Multiple successional pathways in human-modified tropical landscapes: new insights from forest succession, forest fragmentation and landscape ecology research.

PubMed

Arroyo-Rodríguez, Víctor; Melo, Felipe P L; Martínez-Ramos, Miguel; Bongers, Frans; Chazdon, Robin L; Meave, Jorge A; Norden, Natalia; Santos, Bráulio A; Leal, Inara R; Tabarelli, Marcelo

2017-02-01

Old-growth tropical forests are being extensively deforested and fragmented worldwide. Yet forest recovery through succession has led to an expansion of secondary forests in human-modified tropical landscapes (HMTLs). Secondary forests thus emerge as a potential repository for tropical biodiversity, and also as a source of essential ecosystem functions and services in HMTLs. Such critical roles are controversial, however, as they depend on successional, landscape and socio-economic dynamics, which can vary widely within and across landscapes and regions. Understanding the main drivers of successional pathways of disturbed tropical forests is critically needed for improving management, conservation, and restoration strategies. Here, we combine emerging knowledge from tropical forest succession, forest fragmentation and landscape ecology research to identify the main driving forces shaping successional pathways at different spatial scales. We also explore causal connections between land-use dynamics and the level of predictability of successional pathways, and examine potential implications of such connections to determine the importance of secondary forests for biodiversity conservation in HMTLs. We show that secondary succession (SS) in tropical landscapes is a multifactorial phenomenon affected by a myriad of forces operating at multiple spatio-temporal scales. SS is relatively fast and more predictable in recently modified landscapes and where well-preserved biodiversity-rich native forests are still present in the landscape. Yet the increasing variation in landscape spatial configuration and matrix heterogeneity in landscapes with intermediate levels of disturbance increases the uncertainty of successional pathways. In landscapes that have suffered extensive and intensive human disturbances, however, succession can be slow or arrested, with impoverished assemblages and reduced potential to deliver ecosystem functions and services. We conclude that: (i

Distal Predominance of Electrodiagnostic Abnormalities in Early Stage Amyotrophic Lateral Sclerosis.

PubMed

Shayya, Luay; Babu, Suma; Pioro, Erik P; Li, Jianbo; Li, Yuebing

2018-05-09

We compare the electrodiagnostic (EDX) yield of limb muscles in revealing lower motor neuron (LMN) dysfunction by electromyography (EMG) in early stage amyotrophic lateral sclerosis (ALS). Single-site retrospective review Results: This study includes 122 consecutive patients with possible ALS as defined by revised El Escorial Criteria. Distal limb muscles show more frequent EMG abnormalities than proximal muscles. EDX yield is higher in the limb where weakness begins and when clinical signs of LMN dysfunction are evident. Adoption of Awaji criteria increases the yield of EMG positive segments significantly in the cervical (p<0.0005) and lumbosacral regions (P<0.0001), and upgrades 19 patients into probable and 1 patient into definite categories. Electromyographic abnormalities are distal limb-predominant in early stage ALS. A redefinition of an EDX-positive cervical or lumbosacral segment, with an emphasis on distal limb muscles, may result in an earlier ALS diagnosis. This article is protected by copyright. All rights reserved. © 2018 Wiley Periodicals, Inc.

Longer-term effects of selective thinning on microarthropod communities in a late-successional coniferous forest.

Treesearch

Robert W. Peck; Christine G. Niwa

2005-01-01

Microarthropod densities within late-successional coniferous forests thinned 16-41 yr before sampling were compared with adjacent unthinned stands to identify longer term effects of thinning on this community. Soil and forest floor layers were sampled separately on eight paired sites. Within the forest floor oribatid, mesostigmatid, and to a marginal extent,...

Rethinking the Food and Drug Administration's 2013 guidance on developing drugs for early-stage Alzheimer's disease.

PubMed

Schneider, Lon S

2014-03-01

The February 2013 Food and Drug Administration (FDA) draft guidance for developing drugs for early-stage Alzheimer's disease (AD) creates certain challenges as they guide toward the use of one cognitive outcome to gain accelerated marketing approval for preclinical AD drugs, and a composite clinical scale - the Clinical Dementia Rating Scale in particular - for the primary outcome for prodromal AD clinical trials. In light of the developing knowledge regarding early stage diagnoses and clinical trials outcomes, we recommend that FDA describe its requirements for validating preclinical AD diagnoses for drug development purposes, maintain the principle for requiring coprimary outcomes, and encourage the advancement of outcomes for early stage AD trials. The principles for drug development for early stage AD should not differ from those for clinical AD, especially as the diagnoses of prodromal and early AD impinge on each other. The FDA should not recommend that a composite scale be used as a sole primary efficacy outcome to support a marketing claim unless it requires that the cognitive and functional components of such a scale are demonstrated to be individually meaningful. The current draft guidelines may inadvertently constrain efforts to better assess the clinical effects of new drugs and inhibit innovation in an area where evidence-based clinical research practices are still evolving. Copyright © 2014 The Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

Neratinib for the treatment of HER2-positive early stage breast cancer.

PubMed

Echavarria, Isabel; López-Tarruella, Sara; Márquez-Rodas, Iván; Jerez, Yolanda; Martin, Miguel

2017-08-01

Despite the advances in the treatment of HER2-positive breast cancer, resistance to actual chemotherapeutic regimens eventually occurs. Neratinib, an orally available pan-inhibitor of the ERBB family, represents an interesting new option for early-stage HER2-positive breast cancer. Areas covered: In this article, the development of neratinib, with a special focus on its potential value in the treatment of early-stage HER2-positive breast cancer, has been reviewed. For this purpose, a literature search was conducted, including preclinical studies, early-phase trials in advanced cancer with neratinib in monotherapy and in combination, and phase II and large phase III trials in the early setting. Management of neratinib-induced toxicity, future perspectives for the drug, and ongoing trials are also discussed in this review. Expert commentary: Neratinib is emerging as a promising oral drug for the treatment of HER2-positive breast cancer. Although FDA and EMA approval is derived from the extended adjuvant treatment, this setting may not be the ideal scenario to obtain the beneficial effects of neratinib. Confirmatory data in the neoadjuvant setting and subgroup analysis from the ExTENET trial might bring some light into the best setting for neratinib therapy. Data from confirmatory trials in the metastatic setting are also required.

Association Between Increased Vascular Density and Loss of Protective RAS in Early-Stage NPDR

NASA Technical Reports Server (NTRS)

Radhakrishnan, Krishnan; Raghunandan, Sneha; Vyas, Ruchi J.; Vu, Amanda C.; Bryant, Douglas; Yaqian, Duan; Knecht, Brenda E.; Grant, Maria B.; Chalam, K . V.; Parsons-Wingerter, Patricia

2016-01-01

Our hypothesis predicts that retinal blood vessels increase in density during early-stage progression to moderate nonproliferative diabetic retinopathy (NPDR). The prevailing paradigm of NPDR progression is that vessels drop out prior to abnormal, vision-impairing regrowth at late-stage proliferative diabetic retinopathy (DR). However, surprising results for our previous preliminary study 1 with NASA's VESsel GENeration Analysis (VESGEN) software showed that vessels proliferated considerably during moderate NPDR compared to drop out at both mild and severe NPDR. Validation of our hypothesis will support development of successful early-stage regenerative therapies such as vascular repair by circulating angiogenic cells (CACs). The renin-angiotensin system (RAS)is implicated in the pathogenesis of DR and in the function of CACs, a critical bone marrow-derived population that is instrumental in vascular repair.

Evaluating the Significance of Viscoelasticity in Diagnosing Early-Stage Liver Fibrosis with Transient Elastography.

PubMed

Zhao, Jingxin; Zhai, Fei; Cheng, Jun; He, Qiong; Luo, Jianwen; Yang, Xueping; Shao, Jinhua; Xing, Huichun

2017-01-01

Transient elastography quantifies the propagation of a mechanically generated shear wave within a soft tissue, which can be used to characterize the elasticity and viscosity parameters of the tissue. The aim of our study was to combine numerical simulation and clinical assessment to define a viscoelastic index of liver tissue to improve the quality of early diagnosis of liver fibrosis. This is clinically relevant, as early fibrosis is reversible. We developed an idealized two-dimensional axisymmetric finite element model of the liver to evaluate the effects of different viscoelastic values on the propagation characteristics of the shear wave. The diagnostic value of the identified viscoelastic index was verified against the clinical data of 99 patients who had undergone biopsy and routine blood tests for staging of liver disease resulting from chronic hepatitis B infection. Liver stiffness measurement (LSM) and the shear wave attenuation fitting coefficient (AFC) were calculated from the ultrasound data obtained by performing transient elastography. Receiver operating curve analysis was used to evaluate the reliability and diagnostic accuracy of LSM and AFC. Compared to LSM, the AFC provided a higher diagnostic accuracy to differentiate early stages of liver fibrosis, namely F1 and F2 stages, with an overall specificity of 81.48%, sensitivity of 83.33% and diagnostic accuracy of 81.82%. AFC was influenced by the level of LSM, ALT. However, there are no correlation between AFC and Age, BMI, TBIL or DBIL. Quantification of the viscoelasticity of liver tissue provides reliable measurement to identify and differentiate early stages of liver fibrosis.

Evaluating the Significance of Viscoelasticity in Diagnosing Early-Stage Liver Fibrosis with Transient Elastography

PubMed Central

Cheng, Jun; He, Qiong; Luo, Jianwen; Yang, Xueping; Shao, Jinhua; Xing, Huichun

2017-01-01

Transient elastography quantifies the propagation of a mechanically generated shear wave within a soft tissue, which can be used to characterize the elasticity and viscosity parameters of the tissue. The aim of our study was to combine numerical simulation and clinical assessment to define a viscoelastic index of liver tissue to improve the quality of early diagnosis of liver fibrosis. This is clinically relevant, as early fibrosis is reversible. We developed an idealized two-dimensional axisymmetric finite element model of the liver to evaluate the effects of different viscoelastic values on the propagation characteristics of the shear wave. The diagnostic value of the identified viscoelastic index was verified against the clinical data of 99 patients who had undergone biopsy and routine blood tests for staging of liver disease resulting from chronic hepatitis B infection. Liver stiffness measurement (LSM) and the shear wave attenuation fitting coefficient (AFC) were calculated from the ultrasound data obtained by performing transient elastography. Receiver operating curve analysis was used to evaluate the reliability and diagnostic accuracy of LSM and AFC. Compared to LSM, the AFC provided a higher diagnostic accuracy to differentiate early stages of liver fibrosis, namely F1 and F2 stages, with an overall specificity of 81.48%, sensitivity of 83.33% and diagnostic accuracy of 81.82%. AFC was influenced by the level of LSM, ALT. However, there are no correlation between AFC and Age, BMI, TBIL or DBIL. Quantification of the viscoelasticity of liver tissue provides reliable measurement to identify and differentiate early stages of liver fibrosis. PMID:28107385

Speech acoustic markers of early stage and prodromal Huntington's disease: a marker of disease onset?

PubMed

Vogel, Adam P; Shirbin, Christopher; Churchyard, Andrew J; Stout, Julie C

2012-12-01

Speech disturbances (e.g., altered prosody) have been described in symptomatic Huntington's Disease (HD) individuals, however, the extent to which speech changes in gene positive pre-manifest (PreHD) individuals is largely unknown. The speech of individuals carrying the mutant HTT gene is a behavioural/motor/cognitive marker demonstrating some potential as an objective indicator of early HD onset and disease progression. Speech samples were acquired from 30 individuals carrying the mutant HTT gene (13 PreHD, 17 early stage HD) and 15 matched controls. Participants read a passage, produced a monologue and said the days of the week. Data were analysed acoustically for measures of timing, frequency and intensity. There was a clear effect of group across most acoustic measures, so that speech performance differed in-line with disease progression. Comparisons across groups revealed significant differences between the control and the early stage HD group on measures of timing (e.g., speech rate). Participants carrying the mutant HTT gene presented with slower rates of speech, took longer to say words and produced greater silences between and within words compared to healthy controls. Importantly, speech rate showed a significant correlation to burden of disease scores. The speech of early stage HD differed significantly from controls. The speech of PreHD, although not reaching significance, tended to lie between the performance of controls and early stage HD. This suggests that changes in speech production appear to be developing prior to diagnosis. Copyright © 2012 Elsevier Ltd. All rights reserved.

Multiple mechanisms of early plant community assembly with stochasticity driving the process.

PubMed

Marteinsdóttir, Bryndís; Svavarsdóttir, Kristín; Thórhallsdóttir, Thóra Ellen

2018-01-01

Initial plant establishment is one of the most critical phases in ecosystem development, where an early suite of physical (environmental filtering), biological (seed limitation, species interactions) and stochastic factors may affect successional trajectories and rates. While functional traits are commonly used to study processes that influence plant community assembly in late successional communities, few studies have applied them to primary succession. The objective here was to determine the importance of these factors in shaping early plant community assembly on a glacial outwash plain, Skeiðarársandur, in SE Iceland using a trait based approach. We used data on vascular plant assemblages at two different spatial scales (community and neighborhood) sampled in 2005 and 2012, and compiled a dataset on seven functional traits linked to species dispersal abilities, establishment, and persistence for all species within these assemblages. Trait-based null model analyses were used to determine the processes that influenced plant community assembly from the regional species pool into local communities, and to determine if the importance of these processes in community assembly was dependent on local environment or changed with time. On the community scale, for most traits, random processes dominated the assembly from the regional species pool. However, in some communities, there was evidence of non-random assembly in relation to traits linked to species dispersal abilities, persistence, and establishment. On the neighborhood scale, assembly was mostly random. The relative importance of different processes varied spatially and temporally and the variation was linked to local soil conditions. While stochasticity dominated assembly patterns of our early successional communities, there was evidence of both seed limitation and environmental filtering. Our results indicated that as soil conditions improved, environmental constraints on assembly became weaker and the

Effects of chronic crude oil exposure on early developmental stages of the Northern krill (Meganyctiphanes norvegica).

PubMed

Arnberg, Maj; Moodley, Leon; Dunaevskaya, Evgenia; Ramanand, Sreerekha; Ingvarsdóttir, Anna; Nilsen, Marianne; Ravagnan, Elisa; Westerlund, Stig; Sanni, Steinar; Tarling, Geraint A; Bechmann, Renée K

2017-01-01

Rising oil and gas activities in northern high latitudes have led to an increased risk of petroleum pollution in these ecosystems. Further, seasonal high UV radiation at high latitudes may elevate photo-enhanced toxicity of petroleum pollution to marine organisms. Zooplanktons are a key ecological component of northern ecosystems; therefore, it is important to assess their sensitivity to potential pollutants of oil and gas activity. As ontogenetic development may be particularly sensitive, the aim of this study was to examine the impact of chronic exposure to oil water dispersion (OWD) on development and feeding of early life stages of the Northern krill, Meganyctiphanes norvegica. In a range of experiments, embryonic, nonfeeding, and feeding larval stages were exposed to concentrations of between 0.01 and 0.1 mg/L of oil or photo-modified oil for 19 and 21 d. No significant effects on egg respiration, hatching success, development, length and larval survival were observed from these treatments. Similarly, evolution of fatty acid composition patterns during ontogenetic development was unaffected. The results indicates a high degree of resilience of these early developmental stages to such types and concentrations of pollutants. However, feeding and motility in later calyptopis-stage larvae were significantly impaired at exposure of 0.1 mg/L oil. Data indicate that feeding larval stage of krill was more sensitive to OWD than early nonfeeding life stages. This might be attributed to the narcotic effects of oil pollutants, their direct ingestion, or accumulated adverse effects over early development.

Couple-Focused Group Intervention for Women With Early Stage Breast Cancer

ERIC Educational Resources Information Center

Manne, Sharon L.; Ostroff, Jamie S.; Winkel, Gary; Fox, Kevin; Grana, Generosa; Miller, Eric; Ross, Stephanie; Frazier, Thomas

2005-01-01

This study examined the efficacy of a couple-focused group intervention on psychological adaptation of women with early stage breast cancer and evaluated whether perceived partner unsupportive behavior or patient functional impairment moderated intervention effects. Two hundred thirty-eight women were randomly assigned to receive either 6 sessions…

Update on the Treatment of Early-Stage Triple-Negative Breast Cancer.

PubMed

Sharma, Priyanka

2018-04-14

Triple-negative breast cancer (TNBC) accounts for 15% of all breast cancers and is associated with poor long-term outcomes compared to other breast cancer subtypes. Currently, chemotherapy remains the main modality of treatment for early-stage TNBC, as there is no approved targeted therapy for this subtype. The biologic heterogeneity of TNBC has hindered the development and evaluation of novel agents, but recent advancements in subclassifying TNBC have paved the way for further investigation of more effective systemic therapies, including cytotoxic and targeted agents. TNBC is enriched for germline BRCA mutation and for somatic deficiencies in homologous recombination DNA repair, the so-called "BRCAness" phenotype. Together, germline BRCA mutations and BRCAness are promising biomarkers of susceptibility to DNA-damaging therapy. Various investigational approaches are consequently being investigated in early-stage TNBC, including immune checkpoint inhibitors, platinum compounds, PI3K pathway inhibitors, and androgen receptor inhibitors. Due to the biological diversity found within TNBC, patient selection based on molecular biomarkers could aid the design of early-phase clinical trials, ultimately accelerating the clinical application of effective new agents. TNBC is an aggressive breast cancer subtype, for which multiple targeted approaches will likely be required for patient outcomes to be substantially improved.

Dissection and Downstream Analysis of Zebra Finch Embryos at Early Stages of Development

PubMed Central

Murray, Jessica R.; Stanciauskas, Monika E.; Aralere, Tejas S.; Saha, Margaret S.

2014-01-01

The zebra finch (Taeniopygiaguttata) has become an increasingly important model organism in many areas of research including toxicology1,2, behavior3, and memory and learning4,5,6. As the only songbird with a sequenced genome, the zebra finch has great potential for use in developmental studies; however, the early stages of zebra finch development have not been well studied. Lack of research in zebra finch development can be attributed to the difficulty of dissecting the small egg and embryo. The following dissection method minimizes embryonic tissue damage, which allows for investigation of morphology and gene expression at all stages of embryonic development. This permits both bright field and fluorescence quality imaging of embryos, use in molecular procedures such as in situ hybridization (ISH), cell proliferation assays, and RNA extraction for quantitative assays such as quantitative real-time PCR (qtRT-PCR). This technique allows investigators to study early stages of development that were previously difficult to access. PMID:24999108

Changes in forest biomass and tree species distribution under climate change in the northeastern United States

Treesearch

Wen J. Wang; Hong S. He; Frank R. Thompson; Jacob S. Fraser; William D. Dijak

2016-01-01

Context. Forests in the northeastern United States are currently in early- and mid-successional stages recovering from historical land use. Climate change will affect forest distribution and structure and have important implications for biodiversity, carbon dynamics, and human well-being. Objective. We addressed how aboveground biomass (AGB) and...

Identification of early B cell precursors (stage 1 and 2 hematogones) in the peripheral blood.

PubMed

Kurzer, Jason H; Weinberg, Olga K

2018-05-25

Differentiating malignant B-lymphoblasts from early benign B cell precursors (hematogones) is a vital component of the diagnosis of B-lymphoblastic leukaemia. It has been previously reported that only late-stage B cell precursors circulate in the peripheral blood. Consequently, flow cytometric detection of cells with immunophenotypic findings similar to earlier stage precursors in the peripheral blood justifiably raises concern for involvement by B-lymphoblastic leukaemia. We report here, however, that benign early B cell precursors can indeed be detected in the peripheral blood, thus complicating the interpretation of flow cytometric findings derived from these sample types. A retrospective search of our collective databases identified 13 cases containing circulating early stage B cell precursors. The patients ranged in age from 15 days to 85 years old. All positive cases demonstrated that the earlier B cell precursors were associated with later stage precursors, a finding that could help differentiate these cells from B-lymphoblastic leukaemia. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Bridging the gap: facilities and technologies for development of early stage therapeutic mAb candidates.

PubMed

Munro, Trent P; Mahler, Stephen M; Huang, Edwin P; Chin, David Y; Gray, Peter P

2011-01-01

Therapeutic monoclonal antibodies (mAbs) currently dominate the biologics marketplace. Development of a new therapeutic mAb candidate is a complex, multistep process and early stages of development typically begin in an academic research environment. Recently, a number of facilities and initiatives have been launched to aid researchers along this difficult path and facilitate progression of the next mAb blockbuster. Complementing this, there has been a renewed interest from the pharmaceutical industry to reconnect with academia in order to boost dwindling pipelines and encourage innovation. In this review, we examine the steps required to take a therapeutic mAb from discovery through early stage preclinical development and toward becoming a feasible clinical candidate. Discussion of the technologies used for mAb discovery, production in mammalian cells and innovations in single-use bioprocessing is included. We also examine regulatory requirements for product quality and characterization that should be considered at the earliest stages of mAb development. We provide details on the facilities available to help researchers and small-biotech build value into early stage product development, and include examples from within our own facility of how technologies are utilized and an analysis of our client base.

The decline of venture capital investment in early-stage life sciences poses a challenge to continued innovation.

PubMed

Fleming, Jonathan J

2015-02-01

A key element required for translating new knowledge into effective therapies is early-stage venture capital that finances the work needed to identify a lead molecule or medical device prototype and to develop it to the proof-of-concept stage. This early investment is distinguished by great uncertainty over whether the molecule or prototype is safe and effective, the stability of the regulatory standards to which clinical trials are designed, and the likelihood that large follow-on investments for commercial development can be secured. Regulatory and reimbursement policies have a profound impact on the amount of capital and the types of life science projects that investors pursue. In this article I analyze several recent trends in early-stage venture capital funding, describe how these trends are influenced by regulatory and reimbursement policies, and discuss the role of policy makers in bringing new treatments to market. Policy makers can foster renewed private investment into critically needed early-stage products by increasing Small Business Innovation Research (SBIR) funding and public support for clinical trials in targeted areas of interest; creating regulatory pathways to enable early testing of experimental compounds in limited populations; and offering economic incentives for investors and developers in designated therapeutic areas. Project HOPE—The People-to-People Health Foundation, Inc.

Persistent and pervasive compositional shifts of western boreal forest plots in Canada.

PubMed

Searle, Eric B; Chen, Han Y H

2017-02-01

Species compositional shifts have important consequences to biodiversity and ecosystem function and services to humanity. In boreal forests, compositional shifts from late-successional conifers to early-successional conifers and deciduous broadleaves have been postulated based on increased fire frequency associated with climate change truncating stand age-dependent succession. However, little is known about how climate change has affected forest composition in the background between successive catastrophic fires in boreal forests. Using 1797 permanent sample plots from western boreal forests of Canada measured from 1958 to 2013, we show that after accounting for stand age-dependent succession, the relative abundances of early-successional deciduous broadleaves and early-successional conifers have increased at the expense of late-successional conifers with climate change. These background compositional shifts are persistent temporally, consistent across all forest stand ages and pervasive spatially across the region. Rising atmospheric CO 2 promoted early-successional conifers and deciduous broadleaves, and warming increased early-successional conifers at the expense of late-successional conifers, but compositional shifts were not associated with climate moisture index. Our results emphasize the importance of climate change on background compositional shifts in the boreal forest and suggest further compositional shifts as rising CO 2 and warming will continue in the 21st century. © 2016 John Wiley & Sons Ltd.

In Vivo Dark-Field Radiography for Early Diagnosis and Staging of Pulmonary Emphysema.

PubMed

Hellbach, Katharina; Yaroshenko, Andre; Meinel, Felix G; Yildirim, Ali Ö; Conlon, Thomas M; Bech, Martin; Mueller, Mark; Velroyen, Astrid; Notohamiprodjo, Mike; Bamberg, Fabian; Auweter, Sigrid; Reiser, Maximilian; Eickelberg, Oliver; Pfeiffer, Franz

2015-07-01

The aim of this study was to evaluate the suitability of in vivo x-ray dark-field radiography for early-stage diagnosis of pulmonary emphysema in mice. Furthermore, we aimed to analyze how the dark-field signal correlates with morphological changes of lung architecture at distinct stages of emphysema. Female 8- to 10-week-old C57Bl/6N mice were used throughout all experiments. Pulmonary emphysema was induced by orotracheal injection of porcine pancreatic elastase (80-U/kg body weight) (n = 30). Control mice (n = 11) received orotracheal injection of phosphate-buffered saline. To monitor the temporal patterns of emphysema development over time, the mice were imaged 7, 14, or 21 days after the application of elastase or phosphate-buffered saline. X-ray transmission and dark-field images were acquired with a prototype grating-based small-animal scanner. In vivo pulmonary function tests were performed before killing the animals. In addition, lungs were obtained for detailed histopathological analysis, including mean cord length (MCL) quantification as a parameter for the assessment of emphysema. Three blinded readers, all of them experienced radiologists and familiar with dark-field imaging, were asked to grade the severity of emphysema for both dark-field and transmission images. Histopathology and MCL quantification confirmed the introduction of different stages of emphysema, which could be clearly visualized and differentiated on the dark-field radiograms, whereas early stages were not detected on transmission images. The correlation between MCL and dark-field signal intensities (r = 0.85) was significantly higher than the correlation between MCL and transmission signal intensities (r = 0.37). The readers' visual ratings for dark-field images correlated significantly better with MCL (r = 0.85) than visual ratings for transmission images (r = 0.36). Interreader agreement and the diagnostic accuracy of both quantitative and visual assessment were significantly higher

Dyslipidogenic microangiopathy in guinea pigs at early stages of atherogenesis.

PubMed

Bersenev, A V; Klimenko, E D; Kobozeva, L P; Michunskaya, A B; Onishchenko, N A; Pozdnyakov, O M

2003-08-01

We studied the effect of dyslipidemia on lipid metabolism, state of microcirculatory system, and morphological alterations in the aorta and liver of guinea pigs at the early stages of experimental atherogenesis. The important role of microcirculatory disorders in the development of regional pathology and atherosclerosis is confirmed. The proposed alimentary model can be used in the development of novel methods for prevention and treatment of atherosclerosis.

Post-Hurricane Successional Dynamics in Abundance and Diversity of Canopy Arthropods in a Tropical Rainforest

Treesearch

T. D. Schowalter; M. R. Willig; S. J. Presley

2017-01-01

We quantified long-term successional trajectories of canopy arthropods on six tree species in a tropical rainforest ecosystem in the Luquillo Mountains of Puerto Rico that experienced repeated hurricane-induced disturbances during the 19-yr study (1991–2009). We expected: 1) differential performances of arthropod species to result in taxon- or guild-specific responses...

Patterns of tree species diversity and composition in old-field successional forests in central Illinois

Treesearch

Scott M. Bretthauer; George Z. Gertner; Gary L. Rolfe; Jeffery O. Dawson

2003-01-01

Tree species diversity increases and dominance decreases with proximity to forest border in two 60-year-old successional forest stands developed on abandoned agricultural land in Piatt County, Illinois. A regression equation allowed us to quantify an increase in diversity with closeness to forest border for one of the forest stands. Shingle oak is the most dominant...

Early-Stage Visual Processing and Cortical Amplification Deficits in Schizophrenia

PubMed Central

Butler, Pamela D.; Zemon, Vance; Schechter, Isaac; Saperstein, Alice M.; Hoptman, Matthew J.; Lim, Kelvin O.; Revheim, Nadine; Silipo, Gail; Javitt, Daniel C.

2005-01-01

Background Patients with schizophrenia show deficits in early-stage visual processing, potentially reflecting dysfunction of the magnocellular visual pathway. The magnocellular system operates normally in a nonlinear amplification mode mediated by glutamatergic (N-methyl-d-aspartate) receptors. Investigating magnocellular dysfunction in schizophrenia therefore permits evaluation of underlying etiologic hypotheses. Objectives To evaluate magnocellular dysfunction in schizophrenia, relative to known neurochemical and neuroanatomical substrates, and to examine relationships between electrophysiological and behavioral measures of visual pathway dysfunction and relationships with higher cognitive deficits. Design, Setting, and Participants Between-group study at an inpatient state psychiatric hospital and out-patient county psychiatric facilities. Thirty-three patients met DSM-IV criteria for schizophrenia or schizoaffective disorder, and 21 nonpsychiatric volunteers of similar ages composed the control group. Main Outcome Measures (1) Magnocellular and parvocellular evoked potentials, analyzed using nonlinear (Michaelis-Menten) and linear contrast gain approaches; (2) behavioral contrast sensitivity measures; (3) white matter integrity; (4) visual and nonvisual neuropsychological measures, and (5) clinical symptom and community functioning measures. Results Patients generated evoked potentials that were significantly reduced in response to magnocellular-biased, but not parvocellular-biased, stimuli (P=.001). Michaelis-Menten analyses demonstrated reduced contrast gain of the magnocellular system (P=.001). Patients showed decreased contrast sensitivity to magnocellular-biased stimuli (P<.001). Evoked potential deficits were significantly related to decreased white matter integrity in the optic radiations (P<.03). Evoked potential deficits predicted impaired contrast sensitivity (P=.002), which was in turn related to deficits in complex visual processing (P≤.04). Both

Fish early life stage: Developing AOPs to support targeted reduction and replacement

EPA Science Inventory

There is an interest in developing alternatives to the fish early-life stage (FELS) test (OECD test guideline 210), for predicting adverse chronic toxicity outcomes (e.g., impacts on growth and survival). Development and characterization of adverse outcome pathways (AOPs) related...

Controlling fear: Jordanian women's perceptions of the diagnosis and surgical treatment of early-stage breast cancer.

PubMed

Obeidat, Rana F; Dickerson, Suzanne S; Homish, Gregory G; Alqaissi, Nesreen M; Lally, Robin M

2013-01-01

Despite the fact that breast cancer is the most prevalent cancer among Jordanian women, practically nothing is known about their perceptions of early-stage breast cancer and surgical treatment. The objective of this study was to gain understanding of the diagnosis and surgical treatment experience of Jordanian women with a diagnosis of early-stage breast cancer. An interpretive phenomenological approach was used for this study. A purposive sample of 28 Jordanian women who were surgically treated for early-stage breast cancer within 6 months of the interview was recruited. Data were collected using individual interviews and analyzed using Heideggerian hermeneutical methodology. Fear had a profound effect on Jordanian women's stories of diagnosis and surgical treatment of early-stage breast cancer. Women's experience with breast cancer and its treatment was shaped by their preexisting fear of breast cancer, the disparity in the quality of care at various healthcare institutions, and sociodemographic factors (eg, education, age). Early after the diagnosis, fear was very strong, and women lost perspective of the fact that this disease was treatable and potentially curable. To control their fears, women unconditionally trusted God, the healthcare system, surgeons, family, friends, and/or neighbors and often accepted treatment offered by their surgeons without questioning. Jordanian healthcare providers have a responsibility to listen to their patients, explore meanings they ascribe to their illness, and provide women with proper education and the support necessary to help them cope with their illness.

Ant-diaspore interactions during secondary succession in the Atlantic forest of Brazil.

PubMed

Zwiener, Victor P; Bihn, Jochen H; Marques, Márcia C M

2012-06-01

Animal-plant interactions are important for the recovery of diversity and processes in secondary forests, which increasingly dominate the tropical landscape. We used a combination of observational and experimental approaches to study the interactions of ants with diaspores across a successional gradient of forests in Southern Brazil, from August 2007 to April 2008. In addition to diaspore removal rates, we assessed the species richness, diversity and behaviour of ants interacting with diaspores, in three replicated sites of four successional stages of forests. We recorded 22 ant species interacting with diaspores (an estimated 15% of the total species pool in the region). Species richness and diversity did not differ among successional stages but the behaviour of ants towards diaspores changed with the age of secondary forests. In old successional stages the removal of entire diaspores was more common than in young successional stages of forests. Concordantly, diaspore removal rates were lowest in the youngest successional stage of secondary forests and increased with the age of forests. These results indicate that ant-diaspore interactions in secondary forests are disturbed and lower removal rates in secondary forests are likely to constrain the recruitment of plant populations during secondary succession.

Regional brain activity during early-stage intense romantic love predicted relationship outcomes after 40 months: an fMRI assessment.

PubMed

Xu, Xiaomeng; Brown, Lucy; Aron, Arthur; Cao, Guikang; Feng, Tingyong; Acevedo, Bianca; Weng, Xuchu

2012-09-20

Early-stage romantic love is associated with activation in reward and motivation systems of the brain. Can these localized activations, or others, predict long-term relationship stability? We contacted participants from a previous fMRI study of early-stage love by Xu et al. [34] after 40 months from initial assessments. We compared brain activation during the initial assessment at early-stage love for those who were still together at 40 months and those who were apart, and surveyed those still together about their relationship happiness and commitment at 40 months. Six participants who were still with their partners at 40 months (compared to six who had broken up) showed less activation during early-stage love in the medial orbitofrontal cortex, right subcallosal cingulate and right accumbens, regions implicated in long-term love and relationship satisfaction [1,2]. These regions of deactivation at the early stage of love were also negatively correlated with relationship happiness scores collected at 40 months. Other areas involved were the caudate tail, and temporal and parietal lobes. These data are preliminary evidence that neural responses in the early stages of romantic love can predict relationship stability and quality up to 40 months later in the relationship. The brain regions involved suggest that forebrain reward functions may be predictive for relationship stability, as well as regions involved in social evaluation, emotional regulation, and mood. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Survival benefit of patients with early-stage ovarian carcinoma treated with paclitaxel chemotherapeutic regimens

PubMed Central

2018-01-01

Objective Adjuvant chemotherapy was introduced in patients with early-stage ovarian cancer (OC). The benefit of standard chemotherapeutic regimens including taxane has not been established. Methods Patients with early-stage OC from the National Health Insurance Research database of Taiwan who received platinum plus cyclophosphamide (CP) or platinum plus paclitaxel (PT) for 3–6 cycles were recruited, and the disease-free survival (DFS) and overall survival (OS) were determined. Results A total of 1,510 early-stage OC patients, including 841 who received CP regimen and 699 who received PT regimen, were included. The 2 groups had a similar estimated probability of 5-year DFS (PT vs. CP, 79.0% vs. 77.6%; p=0.410) and OS (84.6% vs. 84.3%; p=0.691). Patients >50 years of age who received the CP regimen had a lower 5-year DFS than the patients ≤50 years of age who received the CP (p<0.001) or PT regimens (p=0.001). Additionally, patients >50 years of age who received the CP regimen had a worse 5-year OS compared with the other 3 groups (p=0.019) (p=0.179 for patients >50 years of age in the PT group; p=0.002 for patients ≤50 years of age in the CP group; and p=0.061 for patients ≤50 years of age in the PT group). Patients with the CP or PT regimen for 3–5 cycles had a similar 5-year DFS and OS compared to 6 cycles (p>0.050). Conclusion Chemotherapeutic regimens with taxane could be recommended for early-stage OC patients >50 years of age. PMID:29185274

Stage-dependent remodeling of the nuclear envelope and lamina during rabbit early embryonic development.

PubMed

Popken, Jens; Schmid, Volker J; Strauss, Axel; Guengoer, Tuna; Wolf, Eckhard; Zakhartchenko, Valeri

2016-04-22

Utilizing 3D structured illumination microscopy, we investigated the quality and quantity of nuclear invaginations and the distribution of nuclear pores during rabbit early embryonic development and identified the exact time point of nucleoporin 153 (NUP153) association with chromatin during mitosis. Contrary to bovine early embryonic nuclei, featuring almost exclusively nuclear invaginations containing a small volume of cytoplasm, nuclei in rabbit early embryonic stages show additionally numerous invaginations containing a large volume of cytoplasm. Small-volume invaginations frequently emanated from large-volume nuclear invaginations but not vice versa, indicating a different underlying mechanism. Large- and small-volume nuclear envelope invaginations required the presence of chromatin, as they were restricted to chromatin-positive areas. The chromatin-free contact areas between nucleolar precursor bodies (NPBs) and large-volume invaginations were free of nuclear pores. Small-volume invaginations were not in contact with NPBs. The number of invaginations and isolated intranuclear vesicles per nucleus peaked at the 4-cell stage. At this stage, the nuclear surface showed highly concentrated clusters of nuclear pores surrounded by areas free of nuclear pores. Isolated intranuclear lamina vesicles were usually NUP153 negative. Cytoplasmic, randomly distributed NUP153-positive clusters were highly abundant at the zygote stage and decreased in number until they were almost absent at the 8-cell stage and later. These large NUP153 clusters may represent a maternally provided NUP153 deposit, but they were not visible as clusters during mitosis. Major genome activation at the 8- to 16-cell stage may mark the switch from a necessity for a deposit to on-demand production. NUP153 association with chromatin is initiated during metaphase before the initiation of the regeneration of the lamina. To our knowledge, the present study demonstrates for the first time major remodeling

Early two-stage double opposing Z-plasty or one-stage push-back palatoplasty?: comparisons in maxillary development and speech outcome at 4 years of age.

PubMed

Yamanishi, Tadashi; Nishio, Juntaro; Sako, Michiyo; Kohara, Hiroshi; Hirano, Yoshiko; Yamanishi, Yukiko; Adachi, Tadafumi; Miya, Shigenori; Mukai, Takao

2011-02-01

Determining the optimal timing and procedure of palatal surgery for children with cleft lip and palate has long raised a major controversy. An early two-stage palatoplasty protocol has been a recent trend in an attempt to obtain preferable maxillary growth without compromising adequate speech development. In this study, we aim to address whether the resulting maxillofacial growth and speech development obtained by an early 2-stage palatoplasty protocol are better than those obtained by conventional 1-stage push-back palatoplasty. Seventy-two nonsyndromic children with complete unilateral cleft lip and palate were enrolled in this study. They were divided into 2 groups: 30 children, who were treated with early 2-stage palatoplasty, in which soft palate closure was performed using a modified Furlow's procedure at 12 months of age and hard palate closure was performed at 18 months of age (Early Tow Stage [ETS] group: 22 boys, 8 girls), and 42 children, who underwent 1-stage Wardill-Kilner push-back palatoplasty at 12 months of age (Push Back [PB] group: 31 boys, 11 girls). Cephalometric analysis for maxillofacial growth and assessments of speech development were performed for each child at 4 years of age. The ETS group showed a lager maxillary length than the PB group [anterior nasal spine (ANS)-ptm': ETS, 46.7 ± 2.0 mm; PB, 43.6 ± 2.3 mm]. The ANS in the ETS group was positioned more anteriorly than that in the PB group (N'-ANS: ETS, 2.5 ± 1.8 mm; PB, 0.26 ± 2.5 mm), whereas the posterior edge of the maxilla positioned anteroposteiorly was comparable between the 2 groups. The anterior facial height was significantly greater in the ETS group than in the PB group (N-N': ETS, 43.3 ± 2.9 mm; PB, 40.1 ± 2.3 mm, S-S': ETS, 29.7 ± 3.2 mm; PB, 31.0 ± 3.2 mm). No statistically significant differences were observed in the incidence of either velopharyngeal incompetence or articulation errors between the 2 groups at 4 years of age. Our results show that the early 2

Pair-wise comparison analysis of differential expression of mRNAs in early and advanced stage primary colorectal adenocarcinomas

PubMed Central

Lau, Tze Pheng; Roslani, April Camilla; Lian, Lay Hoong; Chai, Hwa Chia; Lee, Ping Chin; Hilmi, Ida; Goh, Khean Lee; Chua, Kek Heng

2014-01-01

Objectives To characterise the mRNA expression patterns of early and advanced stage colorectal adenocarcinomas of Malaysian patients. Design Comparative expression analysis. Setting and participants We performed a combination of annealing control primer (ACP)-based PCR and reverse transcription-quantitative real-time PCR for the identification of differentially expressed genes (DEGs) associated with early and advanced stage primary colorectal tumours. We recruited four paired samples from patients with colorectal cancer (CRC) of Dukes’ A and B for the preliminary differential expression study, and a total of 27 paired samples, ranging from CRC stages I to IV, for subsequent confirmatory test. The tumouric samples were obtained from the patients with CRC undergoing curative surgical resection without preoperative chemoradiotherapy. The recruited patients with CRC were newly diagnosed with CRC, and were not associated with any hereditary syndromes, previously diagnosed cancer or positive family history of CRC. The paired non-cancerous tissue specimens were excised from macroscopically normal colonic mucosa distally located from the colorectal tumours. Primary and secondary outcome measures The differential mRNA expression patterns of early and advanced stage colorectal adenocarcinomas compared with macroscopically normal colonic mucosa were characterised by ACP-based PCR and reverse transcription-quantitative real-time PCR. Results The RPL35, RPS23 and TIMP1 genes were found to be overexpressed in both early and advanced stage colorectal adenocarcinomas (p<0.05). However, the ARPC2 gene was significantly underexpressed in early colorectal adenocarcinomas, while the advanced stage primary colorectal tumours exhibited an additional overexpression of the C6orf173 gene (p<0.05). Conclusions We characterised two distinctive gene expression patterns to aid in the stratification of primary colorectal neoplasms among Malaysian patients with CRC. Further work can be done to

Landscape- vs gap-level controls on the abundance of a fire-sensitive, late-successional tree species.

Treesearch

Michael C. Wimberly; Thomas A. Spies

2002-01-01

Tsuga heterophylla (western hemlock), a fire-sensitive, late-successional tree species, is an important component of old-growth forests in the Pacific Northwest, USA. In the Oregon Coast Range, however, T. heterophylla occurs at low densities in or is completely absent from many conifer stands. We used a cellular automata-based...

Direct and Indirect Drivers of Moss Community Structure, Function, and Associated Microfauna Across a Successional Gradient

Treesearch

Micael Jonsson; Paul Kardol; Michael J. Gundale; Sheel Bansal; Marie-Charlotte Nilsson; Daniel B. Metcalfe; David A. Wardle

2015-01-01

Relative to vascular plants, little is known about what factors control bryophyte communities or how they respond to successional and environmental changes. Bryophytes are abundant in boreal forests, thus changes in moss community composition and functional traits (for example, moisture and nutrient content; rates of photosynthesis and respiration) may have important...

Effectiveness of oxfendazole against early and later 4th-stage Strongylus vulgaris in ponies.

PubMed

Slocombe, J O; McCraw, B M; Pennock, P; Ducharme, N G; Baird, J D

1986-03-01

Twenty pony foals (reared worm free), 6.5 to 10 weeks of age, were inoculated with Strongylus vulgaris and allocated to 5 groups, each with 4 foals. One week after inoculation, 1 group of 4 foals was given oxfendazole (OFZ) at a dosage rate of 10 mg/kg of body weight, another group was given 2 such treatments 48 hours apart, and a 3rd group was given a placebo. All treatments were administered by stomach tube. Three weeks later, foals were euthanatized and necropsied in a test for efficacy against early 4th-stage larvae. Oxfendazole was 80% and 94.9% effective against early 4th-stage S vulgaris with 1 and 2 doses, respectively. A 4th group of 4 foals was given 2 treatments of OFZ, 48 hours apart, about 8 weeks after inoculation, and a 5th group was given a placebo. These foals were euthanatized and necropsied 5 weeks after treatment in a test for efficacy against later 4th-stage larvae. Two doses of OFZ were 96.6% effective against later 4th-stage larvae.

Successional stage of biological soil crusts: an accurate indicator of ecohydrological condition

USGS Publications Warehouse

Belnap, Jayne; Wilcox, Bradford P.; Van Scoyoc, Matthew V.; Phillips, Susan L.

2013-01-01

Biological soil crusts are a key component of many dryland ecosystems. Following disturbance, biological soil crusts will recover in stages. Recently, a simple classification of these stages has been developed, largely on the basis of external features of the crusts, which reflects their level of development (LOD). The classification system has six LOD classes, from low (1) to high (6). To determine whether the LOD of a crust is related to its ecohydrological function, we used rainfall simulation to evaluate differences in infiltration, runoff, and erosion among crusts in the various LODs, across a range of soil depths and with different wetting pre-treatments. We found large differences between the lowest and highest LODs, with runoff and erosion being greatest from the lowest LOD. Under dry antecedent conditions, about 50% of the water applied ran off the lowest LOD plots, whereas less than 10% ran off the plots of the two highest LODs. Similarly, sediment loss was 400 g m-2 from the lowest LOD and almost zero from the higher LODs. We scaled up the results from these simulations using the Rangeland Hydrology and Erosion Model. Modelling results indicate that erosion increases dramatically as slope length and gradient increase, especially beyond the threshold values of 10 m for slope length and 10% for slope gradient. Our findings confirm that the LOD classification is a quick, easy, nondestructive, and accurate index of hydrological condition and should be incorporated in field and modelling assessments of ecosystem health.

Is Breast Conserving Therapy a Safe Modality for Early-Stage Male Breast Cancer?

PubMed

Zaenger, David; Rabatic, Bryan M; Dasher, Byron; Mourad, Waleed F

2016-04-01

Male breast cancer (MBC) is a rare disease and lacks data-based treatment guidelines. Most men are currently treated with modified radical mastectomy (MRM) or simple mastectomy (SM). We compared the oncologic treatment outcomes of early-stage MBC to determine whether breast conservation therapy (BCT) is appropriate. We searched the Surveillance, Epidemiology, and End Results database for MBC cases. That cohort was narrowed to cases of stage I-II, T1-T2N0 MBC with surgical and radiation therapy (RT) data available. The patients had undergone MRM, SM, or breast conservation surgery (BCS) with or without postoperative RT. We calculated the actuarial 5-year cause-specific survival (CSS). We identified 6263 MBC cases and included 1777 men with stage I or II, T1-T2, node-negative disease, who had the required treatment information available. MRM without RT was the most common treatment (43%). Only 17% underwent BCS. Of the BCS patients, 46% received adjuvant RT to complete the traditional BCT. No deaths were recorded in the BCT group, regardless of stage, or in the 3 stage I surgical groups if the men had received RT. The actuarial 5-year CSS was 100% in each BCT group. MRM alone resulted in an actuarial 5-year CSS of 97.3% for stage 1% and 91.2% for stage 2. The results from our study suggest that BCT for early-stage MBC yields comparable survival compared with more invasive treatment modalities (ie, MRM or SM alone). This could shift the treatment paradigm to less-invasive interventions and might have the added benefit of increased functional and psychological outcomes. Further prospective studies are needed to confirm our conclusions. Copyright © 2016 Elsevier Inc. All rights reserved.

Turbulence considerations for comparing ecosystem exchange over old-growth and clear-cut stands for limited fetch and complex canopy flow conditions

Treesearch

Sonia Wharton; Matt Schroeder; Kyaw Tha Paw U; Matthias Falk; Ken Bible

2009-01-01

Carbon dioxide (CO2), water vapor, and energy fluxes were measured using eddy covariance (EC) methodology over three adjacent evergreen forests in southern Washington State to identify stand-level age-effects on ecosystem exchange. The sites represent Douglas-fir forest ecosystems at two contrasting successional stages: old-growth (OG) and early...

Two consecutive pregnancies in early and late stage of amyotrophic lateral sclerosis.

PubMed

Sarafov, Stayko; Doitchinova, Maryana; Karagiozova, Zhvka; Slancheva, Boriana; Dengler, Reinhard; Petri, Susanne; Kollewe, Katja

2009-01-01

There are few reports on pregnancies in sporadic and familial amyotrophic lateral sclerosis (ALS). We report on a young woman with sporadic ALS who gave birth twice during the course of her disease. The first pregnancy occurred 13 months after the onset of symptoms, and one month after diagnosis. The pregnancy was uncomplicated and resulted in vaginal delivery of a healthy boy. Fifteen months later, when she was already bed-ridden, she became pregnant again. She received a percutaneous endoscopic gastrostomy in the 21st gestational week and underwent early Caesarean section in the 34th week of gestation. The child was ventilated for 72 h in a neonatological unit. The patient was tracheotomized and ventilated two months later, i.e. 47 months after symptom onset, and died nine months later from gastrointestinal haemorrhage. Her two children have developed without abnormalities to date. This case confirms that pregnancies in early-stage ALS can develop normally and may result in uncomplicated vaginal delivery. Pregnancies in late stages may be critical for mother and child, and early delivery by Caesarean section may become necessary although neonatal outcome can be good.

IgG1-iS18 impedes the adhesive and invasive potential of early and late stage malignant melanoma cells.

PubMed

Munien, Carmelle; Rebelo, Thalia M; Ferreira, Eloise; Weiss, Stefan F T

2017-02-15

The 37kDa/67kDa laminin receptor (LRP/LR) is a non-integrin laminin receptor which is overexpressed in tumorigenic cells and supports progression of cancer via promoting metastasis, angiogenesis and telomerase activity and impediment of apoptosis. The present study investigates the role of LRP/LR on the metastatic potential of early (A375) and late (A375SM) stage malignant melanoma cells. Flow cytometry revealed that both early and late stage malignant melanoma cells display high levels of LRP/LR on their cell surface. Flow cytometry and western blot analysis showed that late stage malignant melanoma cells display significantly higher total and cell surface LRP/LR levels in comparison to early stage malignant melanoma cells and the poorly invasive breast cancer (MCF-7) control cell line. Targeting LRP/LR using the LRP/LR specific antibody IgG1-iS18 resulted in a significant reduction of the adhesive potential to laminin-1 and the invasive potential through the 'ECM-simulating' Matrigel™ of both early and late stage malignant melanoma cells. Furthermore, Pearson's correlation coefficient confirmed that increased LRP levels correlate with the increased invasive and adhesive potential in early and late stage melanoma cells. Thus, blocking LRP/LR using the IgG1-iS18 antibody may therefore be a promising therapeutic strategy for early and late stage malignant melanoma treatment. Copyright © 2017 Elsevier Inc. All rights reserved.

Early, asymptomatic stage of degenerative joint disease in canine hip joints.

PubMed

Lust, G; Summers, B A

1981-11-01

The early stages of degenerative joint disease were investigated in coxofemoral joints from dogs with a hereditary predisposition to hip dysplasia. Alterations observed included mild nonsuppurative synovitis, increased volume of both synovial fluid and the ligamentum teres, and focal degenerative articular cartilage lesions. On radiologic examination, subluxation of the femoral head was seen, but only in the most severely affected joints. Synovial inflammation with increased synovial fluid and ligament volumes were indicators of early degenerative joint disease in dogs. These changes seemed to coincide with, or perhaps to precede, microscopic evidence for articular cartilage degeneration and occurred before radiologic abnormalities were detected.

Factors influencing recruitment of walleye and white bass to three distinct early ontogenetic stages

USGS Publications Warehouse

DeBoer, Jason A.; Pope, Kevin L.

2015-01-01

Determining the factors that influence recruitment to sequential ontogenetic stages is critical for understanding recruitment dynamics of fish and for effective management of sportfish, particularly in dynamic and unpredictable environments. We sampled walleye (Sander vitreus) and white bass (Morone chrysops) at 3 ontogenetic stages (age 0 during spring: ‘age-0 larval’; age 0 during autumn: ‘age-0 juvenile’; and age 1 during autumn: ‘age-1 juvenile’) from 3 reservoirs. We developed multiple linear regression models to describe factors influencing age-0 larval, age-0 juvenile and age-1 juvenile walleye and white bass abundance indices. Our models explained 40–80% (68 ± 9%; mean ± SE) and 71%–97% (81 ± 6%) of the variability in catch for walleye and white bass respectively. For walleye, gizzard shad were present in the candidate model sets for all three ontogenetic stages we assessed. For white bass, there was no unifying variable in all three stage-specific candidate model sets, although walleye abundance was present in two of the three white bass candidate model sets. We were able to determine several factors affecting walleye and white bass year-class strength at multiple ontogenetic stages; comprehensive analyses of factors influencing recruitment to multiple early ontogenetic stages are seemingly rare in the literature. Our models demonstrate the interdependency among early ontogenetic stages and the complexities involved with sportfish recruitment.

Thermodynamics, morphology, and kinetics of early-stage self-assembly of π-conjugated oligopeptides

DOE Office of Scientific and Technical Information (OSTI.GOV)

None, None

Synthetic oligopeptides containing π-conjugated cores self-assemble novel materials with attractive electronic and photophysical properties. All-atom, explicit solvent molecular dynamics simulations of Asp-Phe-Ala-Gly-OPV3-Gly-Ala-Phe-Asp peptides were used to parameterize an implicit solvent model to simulate early-stage self-assembly. Under low-pH conditions, peptides assemble into β-sheet-like stacks with strongly favorable monomer association free energies of ΔF ≈ -25kBT. Aggregation at high-pH produces disordered aggregates destabilized by Coulombic repulsion between negatively charged Asp termini (ΔF ≈ -5kBT). In simulations of hundreds of monomers over 70 ns we observe the spontaneous formation of up to undecameric aggregates under low-pH conditions. Modeling assembly as a continuous-time Markovmore » process, we infer transition rates between different aggregate sizes and microsecond relaxation times for early-stage assembly. Our data suggests a hierarchical model of assembly in which peptides coalesce into small clusters over tens of nanoseconds followed by structural ripening and diffusion limited aggregation on longer time scales. This work provides new molecular-level understanding of early-stage assembly, and a means to study the impact of peptide sequence and aromatic core chemistry upon the thermodynamics, assembly kinetics, and morphology of the supramolecular aggregates.« less

Thermodynamics, morphology, and kinetics of early-stage self-assembly of π-conjugated oligopeptides

DOE PAGES

None, None

2016-03-22

Synthetic oligopeptides containing π-conjugated cores self-assemble novel materials with attractive electronic and photophysical properties. All-atom, explicit solvent molecular dynamics simulations of Asp-Phe-Ala-Gly-OPV3-Gly-Ala-Phe-Asp peptides were used to parameterize an implicit solvent model to simulate early-stage self-assembly. Under low-pH conditions, peptides assemble into β-sheet-like stacks with strongly favorable monomer association free energies of ΔF ≈ -25kBT. Aggregation at high-pH produces disordered aggregates destabilized by Coulombic repulsion between negatively charged Asp termini (ΔF ≈ -5kBT). In simulations of hundreds of monomers over 70 ns we observe the spontaneous formation of up to undecameric aggregates under low-pH conditions. Modeling assembly as a continuous-time Markovmore » process, we infer transition rates between different aggregate sizes and microsecond relaxation times for early-stage assembly. Our data suggests a hierarchical model of assembly in which peptides coalesce into small clusters over tens of nanoseconds followed by structural ripening and diffusion limited aggregation on longer time scales. This work provides new molecular-level understanding of early-stage assembly, and a means to study the impact of peptide sequence and aromatic core chemistry upon the thermodynamics, assembly kinetics, and morphology of the supramolecular aggregates.« less

Prognostic factors for patients with early-stage uterine serous carcinoma without adjuvant therapy.

PubMed

Tate, Keisei; Yoshida, Hiroshi; Ishikawa, Mitsuya; Uehara, Takashi; Ikeda, Shun Ichi; Hiraoka, Nobuyoshi; Kato, Tomoyasu

2018-05-01

Uterine serous carcinoma (USC) is an aggressive type 2 endometrial cancer. Data on prognostic factors for patients with early-stage USC without adjuvant therapy are limited. This study aims to assess the baseline recurrence risk of early-stage USC patients without adjuvant treatment and to identify prognostic factors and patients who need adjuvant therapy. Sixty-eight patients with International Federation of Gynecology and Obstetrics (FIGO) stage I-II USC between 1997 and 2016 were included. All the cases did not undergo adjuvant treatment as institutional practice. Clinicopathological features, recurrence patterns, and survival outcomes were analyzed to determine prognostic factors. FIGO stages IA, IB, and II were observed in 42, 7, and 19 cases, respectively. Median follow-up time was 60 months. Five-year disease-free survival (DFS) and overall survival (OS) rates for all cases were 73.9% and 78.0%, respectively. On multivariate analysis, cervical stromal involvement and positive pelvic cytology were significant predictors of DFS and OS, and ≥1/2 myometrial invasion was also a significant predictor of OS. Of 68 patients, 38 patients had no cervical stromal invasion or positive pelvic cytology and showed 88.8% 5-year DFS and 93.6% 5-year OS. Cervical stromal invasion and positive pelvic cytology are prognostic factors for stage I-II USC. Patients with stage IA or IB USC showing negative pelvic cytology may have an extremely favorable prognosis and need not receive any adjuvant therapies. Copyright © 2018. Asian Society of Gynecologic Oncology, Korean Society of Gynecologic Oncology.

Invasive Congeners Differ in Successional Impacts across Space and Time

PubMed Central

David, Aaron S.; Zarnetske, Phoebe L.; Hacker, Sally D.; Ruggiero, Peter; Biel, Reuben G.; Seabloom, Eric W.

2015-01-01

Invasive species can alter the succession of ecological communities because they are often adapted to the disturbed conditions that initiate succession. The extent to which this occurs may depend on how widely they are distributed across environmental gradients and how long they persist over the course of succession. We focus on plant communities of the USA Pacific Northwest coastal dunes, where disturbance is characterized by changes in sediment supply, and the plant community is dominated by two introduced grasses – the long-established Ammophila arenaria and the currently invading A. breviligulata. Previous studies showed that A. breviligulata has replaced A. arenaria and reduced community diversity. We hypothesize that this is largely due to A. breviligulata occupying a wider distribution across spatial environmental gradients and persisting in later-successional habitat than A. arenaria. We used multi-decadal chronosequences and a resurvey study spanning 2 decades to characterize distributions of both species across space and time, and investigated how these distributions were associated with changes in the plant community. The invading A. breviligulata persisted longer and occupied a wider spatial distribution across the dune, and this corresponded with a reduction in plant species richness and native cover. Furthermore, backdunes previously dominated by A. arenaria switched to being dominated by A. breviligulata, forest, or developed land over a 23-yr period. Ammophila breviligulata likely invades by displacing A. arenaria, and reduces plant diversity by maintaining its dominance into later successional backdunes. Our results suggest distinct roles in succession, with A. arenaria playing a more classically facilitative role and A. breviligulata a more inhibitory role. Differential abilities of closely-related invasive species to persist through time and occupy heterogeneous environments allows for distinct impacts on communities during succession. PMID

Stage is a prognostic factor for surgically treated patients with early-stage lip cancer for whom a 'wait and see' policy in terms of neck status has been implemented.

PubMed

Eskiizmir, G; Ozgur, E; Karaca, G; Temiz, P; Yanar, N Hacioglu; Ozyurt, B Cengiz

2017-10-01

To determine the locoregional control and survival rates (in terms of risk factors) of patients who underwent surgical resection of early-stage lip cancer and for whom a 'wait and see' policy in terms of neck status had been implemented. The sociodemographic data, tumour stage, tumour characteristics and histopathological features of 41 patients with early-stage lip cancer were evaluated. Factors predictive of survival and locoregional recurrence were analysed. The five-year overall survival and disease-free survival rates were determined, and the prognostic risk factors were compared. The mean follow-up period was 60.5 months (range, 4-92 months). Age, sex, tumour stage, tumour thickness and volume, and perineural involvement were not predictive of locoregional recurrence or survival. Pathological tumour stage (T1 vs T2) was a prognostic factor for both five-year overall survival (87.3 vs 65.6 per cent, p = 0.042) and disease-free survival (88.6 vs 65.6 per cent, p = 0.037). Tumour stage was clearly a major factor affecting the prognosis of surgically treated patients with early-stage lip cancer for whom a 'wait and see' policy in terms of neck status had been implemented.

Dynamics of laser ablation at the early stage during and after ultrashort pulse

NASA Astrophysics Data System (ADS)

Ilnitsky, D. K.; Khokhlov, V. A.; Zhakhovsky, V. V.; Petrov, Yu V.; Migdal, K. P.; Inogamov, N. A.

2016-11-01

Study of material flow in two-temperature states is needed for a fundamental understanding the physics of femtosecond laser ablation. To explore phenomena at a very early stage of laser action on a metallic target our in-house two-temperature hydrodynamics code is used here. The early stage covers duration of laser pulse with next first few picoseconds. We draw attention to the difference in behavior at this stage between the cases: (i) of an ultrathin film (thickness of order of skin depth d skin or less), (ii) thin films (thickness of a film is 4-7 of d skin for gold), and (iii) bulk targets (more than 10d skin for gold). We demonstrate that these differences follow from a competition among conductive cooling of laser excited electrons in a skin layer, electron-ion coupling, and hydrodynamics of unloading caused by excess of pressure of excited free electrons. Conductive cooling of the skin needs a heat sink, which is performed by the cold material outside the skin. Such sink is unavailable in the ultrathin films.

Repair of Craniomaxillofacial Traumatic Soft Tissue Defects With Tissue Expansion in the Early Stage.

PubMed

Han, Yan; Zhao, Jianhui; Tao, Ran; Guo, Lingli; Yang, Hongyan; Zeng, Wei; Song, Baoqiang; Xia, Wensen

2017-09-01

Craniomaxillofacial traumatic soft tissue defects severely affect the function and appearance of the patients. The traditional skin grafting or free flap transplantation can only close the defects in the early stage of operation but cannot ensure similar color, texture, and relative aesthetic contour. In the present study, the authors have explored a novel strategy to repair craniomaxillofacial traumatic soft tissue defects by tissue expansion in the early stage and have obtained satisfactory results. Eighteen patients suffering large craniomaxillofacial traumatic soft tissue defects were treated by thorough debridement leaving the wounds unclosed or simply closed with thin split-thickness scalp grafts, adjacent expander implantation in the first stage, and expanded flap transposition in the second stage. There were 11 male patients and 7 female patients ranging in age from 3.5 to 40 years (mean, 19.4 ± 12.2 years), with average 15 months follow-up (range, 3-67 months). The average expansion time was 74.3 days (range, 53-96 days). The 18 patients with a total of 22 expanders were treated with satisfactory results. All the flaps survived and the skin color, texture, and contour well matched those of the peripheral tissue. Only 1 complication of infection happened in the 18 cases (5.56%) and the 22 expanders (4.55%), which was similar to the rate reported in the literature. No other complications related to the expanders occurred. Debridement and tissue expansion in the early stage has been proved to be a more effective strategy to repair craniomaxillofacial traumatic soft tissue defects. This strategy can not only achieve satisfactory color, unbulky and well-matched texture similar to normal, but also avoid unnecessary donor site injuries.

Identification of a Genomic Signature Predicting for Recurrence in Early Stage Ovarian Cancer

DTIC Science & Technology

2015-12-01

early stage ovarian cancer to help researchers worldwide identify biomarkers that can aid early detection and inform novel targets for therapy. This...to detect differentially expressed genes after transformation using Voom. When using the top 5 genes to build the classifier, it predicted...to analyze expression of micro-RNA in these samples. Thus, at the end of the third year of funding we started a parallel analysis of RNAseq, DNA- CNV

Hallux abductus interphalangeus in normal feet, early-stage hallux limitus, and hallux valgus.

PubMed

Castillo-Lopez, Jose M; Ramos-Ortega, Javier; Reina-Bueno, Maria; Domínguez-Maldonado, Gabriel; Palomo-Toucedo, Inmaculada C; Munuera, Pedro V

2014-03-01

Excessive deviation of the distal phalanx in abduction frequently occurs in advanced stages of hallux rigidus but not in hallux valgus. Therefore, theoretically there should be no significant differences in the hallux interphalangeal angle (HIPA) between individuals with normal feet, those with hallux valgus, and those with mild hallux limitus. The objective of the present study was thus to determine if significant differences in HIPA exist in the early stages of hallux valgus or hallux limitus deformities. The hallux interphalangeal angle was measured in three groups of participants: a control group with normal feet (45 participants), a hallux valgus group (49 participants), and a hallux limitus group (48 participants). Both of the pathologies were at an early stage. A dorsoplantar radiograph under weightbearing conditions was taken for each individual, and measurements (HIPA and hallux abductus angle [HAA]) were taken using AutoCAD (Autodesk Inc, San Rafael, California) software. Intergroup comparisons of HIPA, and correlations between HIPA, HAA, and hallux dorsiflexion were calculated. The comparisons revealed no significant differences in the values of HIPA between any of the groups (15.2 ± 5.9 degrees in the control group, 15.5 ± 3.9 degrees in the hallux valgus group, and 16.15 ± 4.3 in the hallux limitus group; P  =  0.634). The Pearson correlation coefficients in particular showed no correlation between hallux dorsiflexion, HAA, and HIPA. For the study participants, there were similar deviations of the distal phalanx of the hallux with respect to the proximal phalanx in normal feet and in feet with the early stages of the hallux limitus and hallux valgus deformities.

Cost implications of unwarranted imaging for distant metastasis in women with early-stage breast cancer in Ontario.

PubMed

Thavorn, K; Wang, Z; Fergusson, D; van Katwyk, S; Arnaout, A; Clemons, M

2016-02-01

Despite the publication of multiple evidence-based guidelines recommending against routine imaging for distant metastasis in patients with early-stage (i/ii) breast cancer, such imaging is frequently performed. The present retrospective cohort study was conducted to estimate the cost of unnecessary imaging tests in women with stage i and ii breast cancer diagnosed between 1 January 2007 and 31 December 2012 in Ontario. We obtained patient-level demographic and tumour data from a large provincial dataset. The total cost of unwarranted imaging tests (in 2015 Canadian dollars) was considered to be equal to the sum of imaging costs incurred between 2007 and 2012 and was stratified by disease stage, imaging modality, and body site. Of the 26,547 identified patients with early-stage breast cancer, 22,811 (85.9%) underwent at least 1 imaging test, with an average of 3.7 tests per patient (3.2 for stage i patients and 4.0 for stage ii patients) over 5 years. At least 1 imaging test was performed in 79.6% of stage i and 92.7% of stage ii patients. During a 5-year period, the cost of unwarranted imaging in patients with early-stage breast cancer ranged from CA$4,418,139 to CA$6,865,856, depending on guideline recommendations. Our study highlights the substantial cost of excess imaging that could be saved and re-allocated to patient care if evidence-based guidelines are followed. Future studies should assess strategies to ensure that evidence-based guidelines are followed and to increase awareness of the cost implications of nonadherence to guidelines.

Poor prognosis of uterine serous carcinoma compared with grade 3 endometrioid carcinoma in early stage patients.

PubMed

Park, Ji Young; Nam, Joo-Hyun; Kim, Young-Tak; Kim, Yong-Man; Kim, Jong-Hyeok; Kim, Dae-Yeon; Sohn, Insuk; Lee, Shin-Wha; Sung, Chang Ohk; Kim, Kyu-Rae

2013-03-01

Difference in prognosis between grade 3 endometrioid carcinoma (G3EC) of the endometrium and uterine serous carcinoma (USC) is controversial. In this study, we further evaluated the difference in prognosis, if any, between G3EC (n = 61) and USC (n = 47) on a total of 565 patients with endometrial cancer. In addition, meta-analysis was performed using data from seven previous publications (n = 8,637) and from the Asan Medical Center (n = 108). Regarding the cases from our institution, USC tended to occur in older patients (≥65 years) than G3EC (P = 0.011). Deep myometrial invasion (more than or equal to half) was more frequently identified in G3EC (36/61, 59.0 %) than in USC (17/47, 36.2 %) (P = 0.021). Between patients with early stage G3EC and USC (stages I and II), there were no significant differences in any clinicopathological parameter, but there was a significant difference in overall survival (P = 0.017) that was not found in advanced stage (P = 0.588). USC was an independent prognostic factor for poor overall survival (hazard ratio, 6.125; P = 0.030) in early stage patients. In the meta-analysis on 5-year survival in patients with early stage cancers, which also included our study results, a higher relative risk (1.92, 95 % CI 1.62-2.27) was demonstrated in USC than in G3EC (P < 0.001). In conclusion, our study reveals that USC is associated with a poorer prognosis compared with G3EC, only in patients with early stage carcinoma, suggesting that different treatment strategies should be considered according to the histologic type in order to improve treatment outcome.

Late stages of accumulation and early evolution of the planets

NASA Technical Reports Server (NTRS)

Vityazev, Andrey V.; Perchernikova, G. V.

1991-01-01

Recently developed solutions of problems are discussed that were traditionally considered fundamental in classical solar system cosmogony: determination of planetary orbit distribution patterns, values for mean eccentricity and orbital inclinations of the planets, and rotation periods and rotation axis inclinations of the planets. Two important cosmochemical aspects of accumulation are examined: the time scale for gas loss from the terrestrial planet zone, and the composition of the planets in terms of isotope data. It was concluded that the early beginning of planet differentiation is a function of the heating of protoplanets during collisions with large (thousands of kilometers) bodies. Energetics, heat mass transfer processes, and characteristic time scales of these processes at the early stages of planet evolution are considered.

Forest and wildlife habitat analysis using remote sensing and geographic information systems. M.S. Thesis, 26 May 1992 Abstract Only

NASA Technical Reports Server (NTRS)

Fiorella, Maria

1995-01-01

Forest and wildlife habitat analyses were conducted at the H.J. Andrews Experimental Forest in the Central Cascade Mountains of Oregon using remotely sensed data and a geographic information system (GIS). Landsat Thematic Mapper (TM) data were used to determine forest successional stages, and to analyze the structure of both old and young conifer forests. Two successional stage maps were developed. One was developed from six TM spectral bands alone, and the second was developed from six TM spectral bands and a relative sun incidence band. Including the sun incidence band in the classification improved the mapping accuracy in the two youngest successional stages, but did not improve overall accuracy or accuracy of the two oldest successional stages. Mean spectral values for old-growth and mature stands were compared in seven TM bands and seven band transformations. Differences between mature and old-growth successional stages were greatest for the band ratio of TM 4/5 (P = 0.00005) and the multiband transformation of wetness (P = 0.00003). The age of young conifer stands had the highest correlation to TM 4/5 values (r = 0.9559) of any of the TM band or band transformations used. TM 4/5 ratio values of poorly regenerated conifer stands were significantly different from well regenerated conifer stands after age 15 (P = 0.0000). TM 4/5 was named a 'Successional Stage Index' (SSI) because of its ability to distinguish forest successional stages. The forest successional stage map was used as input into a vertebrate richness model using GIS. The three variables of (1) successional stage, (2) elevation, and (3) site moisture were used in the GIS to predict the spatial occurrence of small mammal, amphibian, and reptile species based on primary and secondary habitat requirements. These occurrence or habitat maps were overlayed to tally the predicted number of vertebrate at any given point in the study area. Overall, sixty-three and sixty-seven percent of the model

Spatio-Temporal Distribution of Bark and Ambrosia Beetles in a Brazilian Tropical Dry Forest

PubMed Central

de Novais, Samuel Matos Antunes; Monteiro, Graziela França; Flechtmann, Carlos Alberto Hector; de Faria, Maurício Lopes; Neves, Frederico de Siqueira

2016-01-01

Bark and the ambrosia beetles dig into host plants and live most of their lives in concealed tunnels. We assessed beetle community dynamics in tropical dry forest sites in early, intermediate, and late successional stages, evaluating the influence of resource availability and seasonal variations in guild structure. We collected a total of 763 beetles from 23 species, including 14 bark beetle species, and 9 ambrosia beetle species. Local richness of bark and ambrosia beetles was estimated at 31 species. Bark and ambrosia composition was similar over the successional stages gradient, and beta diversity among sites was primarily determined by species turnover, mainly in the bark beetle community. Bark beetle richness and abundance were higher at intermediate stages; availability of wood was the main spatial mechanism. Climate factors were effectively non-seasonal. Ambrosia beetles were not influenced by successional stages, however the increase in wood resulted in increased abundance. We found higher richness at the end of the dry and wet seasons, and abundance increased with air moisture and decreased with higher temperatures and greater rainfall. In summary, bark beetle species accumulation was higher at sites with better wood production, while the needs of fungi (host and air moisture), resulted in a favorable conditions for species accumulation of ambrosia. The overall biological pattern among guilds differed from tropical rain forests, showing patterns similar to dry forest areas. PMID:27271969

Reproductive and early life stages pathology - Histopathology workshop report

USGS Publications Warehouse

Bruno, D.W.; Nowak, B.; Elliott, Diane G.

2006-01-01

Pathology occurring during reproduction and larval development represents an important part of the life cycle of fish, and the diseases that affect eggs and larvae often result in significant losses. However, mortality during this period is frequently ignored or poorly researched as the temptation is to replace the losses rather than investigate the causes. A histopathology workshop organised at the newly refurnished laboratory within the Danish Veterinary School was an opportunity to discuss the pathology of selected diseases associated with Reproductive and Early Life Stages Pathology. Several people also kindly provided reference slides.

Risk of Fatal Cerebrovascular Accidents after External Beam Radiation Therapy for Early Stage Glottic Larynx Cancer

PubMed Central

Swisher-McClure, Samuel; Mitra, Nandita; Lin, Alexander; Ahn, Peter; Wan, Fei; O’Malley, Bert; Weinstein, Gregory S.; Bekelman, Justin E.

2013-01-01

Background This study compared the risk of fatal cerebrovascular accidents (CVA) in patients with early stage glottic larynx cancer receiving surgery or external beam radiation therapy (EBRT). Methods and Materials Using a competing risks survival analysis, we compared the risk of death due to CVA among patients with early stage glottic larynx cancer receiving surgery or EBRT in the SEER database. Results The cumulative incidence of fatal CVA at 15 years was higher in patients receiving EBRT (2.8 %; 95% CI 2.3%–3.4%) compared to surgery (1.5 %; 95% CI 0.8 %–2.3%, p= 0.024). In multivariable competing risks regression models, EBRT remained associated with an increased risk of fatal CVA compared to surgery (adjusted HR 1.75; 95% CI 1.04–2.96, p= 0.037). Conclusion Treatment of early stage glottic larynx cancer with EBRT was associated with a small increase in the risk of late fatal CVA events relative to surgery. PMID:23595858

Estimation of Wheat Plant Density at Early Stages Using High Resolution Imagery

PubMed Central

Liu, Shouyang; Baret, Fred; Andrieu, Bruno; Burger, Philippe; Hemmerlé, Matthieu

2017-01-01

Crop density is a key agronomical trait used to manage wheat crops and estimate yield. Visual counting of plants in the field is currently the most common method used. However, it is tedious and time consuming. The main objective of this work is to develop a machine vision based method to automate the density survey of wheat at early stages. RGB images taken with a high resolution RGB camera are classified to identify the green pixels corresponding to the plants. Crop rows are extracted and the connected components (objects) are identified. A neural network is then trained to estimate the number of plants in the objects using the object features. The method was evaluated over three experiments showing contrasted conditions with sowing densities ranging from 100 to 600 seeds⋅m-2. Results demonstrate that the density is accurately estimated with an average relative error of 12%. The pipeline developed here provides an efficient and accurate estimate of wheat plant density at early stages. PMID:28559901

Efficient and Rapid Isolation of Early-stage Embryos from Arabidopsis thaliana Seeds

PubMed Central

Raissig, Michael T.; Gagliardini, Valeria; Jaenisch, Johan; Grossniklaus, Ueli; Baroux, Célia

2013-01-01

In flowering plants, the embryo develops within a nourishing tissue - the endosperm - surrounded by the maternal seed integuments (or seed coat). As a consequence, the isolation of plant embryos at early stages (1 cell to globular stage) is technically challenging due to their relative inaccessibility. Efficient manual dissection at early stages is strongly impaired by the small size of young Arabidopsis seeds and the adhesiveness of the embryo to the surrounding tissues. Here, we describe a method that allows the efficient isolation of young Arabidopsis embryos, yielding up to 40 embryos in 1 hr to 4 hr, depending on the downstream application. Embryos are released into isolation buffer by slightly crushing 250-750 seeds with a plastic pestle in an Eppendorf tube. A glass microcapillary attached to either a standard laboratory pipette (via a rubber tube) or a hydraulically controlled microinjector is used to collect embryos from droplets placed on a multi-well slide on an inverted light microscope. The technical skills required are simple and easily transferable, and the basic setup does not require costly equipment. Collected embryos are suitable for a variety of downstream applications such as RT-PCR, RNA sequencing, DNA methylation analyses, fluorescence in situ hybridization (FISH), immunostaining, and reporter gene assays. PMID:23770918

Effectiveness of a community-based program for suicide prevention among elders with early-stage dementia: A controlled observational study.

PubMed

Kim, Jong-Pill; Yang, Jinhyang

The purpose of this study was to develop a small-group-focused suicide prevention program for elders with early-stage dementia and to assess its effects. This was a quasi-experimental study with a control group pretest-posttest design. A total of 62 elders diagnosed with early-stage dementia who were receiving care services at nine daycare centers in J City Korea participated in this study. The experimental group participated in the suicide prevention program twice a week for 5 weeks with a pretest and two posttests The developed suicide prevention program had a significant effect on the perceived health status, social support, depression, and suicidal ideation of elders with early-stage dementia. Nurses should integrate risk factors such as depression and protective factors such as health status and social support into a suicide prevention program. This community-based program in geriatric nursing practice can be effective in preventing suicide among elders with early-stage dementia. Copyright © 2016 Elsevier Inc. All rights reserved.

The power of personality in discriminating between healthy aging and early-stage Alzheimer's disease.

PubMed

Duchek, Janet M; Balota, David A; Storandt, Martha; Larsen, Randy

2007-11-01

This study examined differences in personality in the earliest stages of dementia of the Alzheimer type (DAT) relative to healthy aging, and the power of personality in discriminating healthy aging from early-stage DAT. Four groups of participants (middle-aged controls, older controls, persons with very mild DAT, and persons with mild DAT) and their families were administered Costa and McCrae's NEO Five-Factor Inventory. On the basis of both self-report and informant report, there was an increase in neuroticism and a decrease in conscientiousness in persons with very mild DAT relative to healthy individuals without it, and in persons with mild DAT relative to those with very mild DAT. Moreover, informant reports of neuroticism and conscientiousness capture substantial unique variance in discriminating healthy aging and very mild DAT, above and beyond standard neuropsychological tests. Discussion focuses on the importance of personality traits as a noncognitive indicator of early-stage DAT.

Successional development of biofilms in moving bed biofilm reactor (MBBR) systems treating municipal wastewater.

PubMed

Biswas, Kristi; Taylor, Michael W; Turner, Susan J

2014-02-01

Biofilm-based technologies, such as moving bed biofilm reactor (MBBR) systems, are widely used to treat wastewater. Biofilm development is important for MBBR systems as much of the microbial biomass is retained within reactors as biofilm on suspended carriers. Little is known about this process of biofilm development and the microorganisms upon which MBBRs rely. We documented successional changes in microbial communities as biofilms established in two full-scale MBBR systems treating municipal wastewater over two seasons. 16S rRNA gene-targeted pyrosequencing and clone libraries were used to describe microbial communities. These data indicate a successional process that commences with the establishment of an aerobic community dominated by Gammaproteobacteria (up to 52 % of sequences). Over time, this community shifts towards dominance by putatively anaerobic organisms including Deltaproteobacteria and Clostridiales. Significant differences were observed between the two wastewater treatment plants (WWTPs), mostly due to a large number of sequences (up to 55 %) representing Epsilonproteobacteria (mostly Arcobacter) at one site. Archaea in young biofilms included several lineages of Euryarchaeota and Crenarchaeota. In contrast, the mature biofilm consisted entirely of Methanosarcinaceae (Euryarchaeota). This study provides new insights into the community structure of developing biofilms at full-scale WWTPs and provides the basis for optimizing MBBR start-up and operational parameters.

Purine-related metabolites and their converting enzymes are altered in frontal, parietal and temporal cortex at early stages of Alzheimer's disease pathology.

PubMed

Alonso-Andrés, Patricia; Albasanz, José Luis; Ferrer, Isidro; Martín, Mairena

2018-01-24

Adenosine, hypoxanthine, xanthine, guanosine and inosine levels were assessed by HPLC, and the activity of related enzymes 5'-nucleotidase (5'-NT), adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) measured in frontal (FC), parietal (PC) and temporal (TC) cortices at different stages of disease progression in Alzheimer's disease (AD) and in age-matched controls. Significantly decreased levels of adenosine, guanosine, hypoxanthine and xanthine, and apparently less inosine, are found in FC from the early stages of AD; PC and TC show an opposing pattern, as adenosine, guanosine and inosine are significantly increased at least at determinate stages of AD whereas hypoxanthine and xanthine levels remain unaltered. 5'-NT is reduced in membranes and cytosol in FC mainly at early stages but not in PC, and only at advanced stages in cytosol in TC. ADA activity is decreased in AD when considered as a whole but increased at early stages in TC. Finally, PNP activity is increased only in TC at early stages. Purine metabolism alterations occur at early stages of AD independently of neurofibrillary tangles and β-amyloid plaques. Alterations are stage dependent and region dependent, the latter showing opposite patterns in FC compared with PC and TC. Adenosine is the most affected of the assessed purines. © 2018 International Society of Neuropathology.

Recurrence of Early Stage Colon Cancer Predicted by Expression Pattern of Circulating microRNAs

PubMed Central

Shivapurkar, Narayan; Weiner, Louis M.; Marshall, John L.; Madhavan, Subha; Deslattes Mays, Anne; Juhl, Hartmut; Wellstein, Anton

2014-01-01

Systemic treatment of patients with early-stage cancers attempts to eradicate occult metastatic disease to prevent recurrence and increased morbidity. However, prediction of recurrence from an analysis of the primary tumor is limited because disseminated cancer cells only represent a small subset of the primary lesion. Here we analyze the expression of circulating microRNAs (miRs) in serum obtained pre-surgically from patients with early stage colorectal cancers. Groups of five patients with and without disease recurrence were used to identify an informative panel of circulating miRs using quantitative PCR of genome-wide miR expression as well as a set of published candidate miRs. A panel of six informative miRs (miR-15a, mir-103, miR-148a, miR-320a, miR-451, miR-596) was derived from this analysis and evaluated in a separate validation set of thirty patients. Hierarchical clustering of the expression levels of these six circulating miRs and Kaplan-Meier analysis showed that the risk of disease recurrence of early stage colon cancer can be predicted by this panel of miRs that are measurable in the circulation at the time of diagnosis (P = 0.0026; Hazard Ratio 5.4; 95% CI of 1.9 to 15). PMID:24400111

Receding Water Line and Interspecific Competition Determines Plant Community Composition and Diversity in Wetlands in Beijing

PubMed Central

Wang, Zhengjun; Gong, Huili; Zhang, Jing

2015-01-01

Climate and human-induced wetland degradation has accelerated in recent years, not only resulting in reduced ecosystem services but also greatly affecting the composition and diversity of wetland plant communities. To date, the knowledge of the differences in community parameters and their successional trends in degraded wetlands remains scarce. Here based on remote sensing images, geographic information system technology, and statistical methods, we produced a successional gradient map of the Yeyahu Wetland Nature Reserve in Beijing, which has experienced a steady decline in water level in recent decades. In addition, we analyzed community composition and diversity along with each identified gradient. The results showed that community diversity decreases while dominance increases with the progress of succession, with the highest diversity occurring during the early stage of succession. Moreover, the community demonstrates greater similarity among subareas during later successional stages, and the similarity coefficients calculated from the important value (IV) of each species are more accurate. Correlation analysis showed that the impact of soil factors on diversity was not significant at a subarea scale, although these nutrients showed an increasing trend with the community succession. Furthermore, the IVs of the dominant species had a particularly significant impact on diversity, showing a significantly negative correlation with diversity indices and a significantly positive correlation with dominance indices. Further analysis showed that the retreat of water level resulted from sustained drought and local human activities was a major extrinsic driving force resulting in observed differences in the community successional stages, which resulted in differences in community composition and diversity. On the other hand, interspecific competition was the main intrinsic mechanism, which significantly influenced the IVs of the dominant species and community diversity

Early stages in the biogenesis of eukaryotic β-barrel proteins.

PubMed

Jores, Tobias; Rapaport, Doron

2017-09-01

The endosymbiotic organelles mitochondria and chloroplasts harbour, similarly to their prokaryotic progenitors, β-barrel proteins in their outer membrane. These proteins are encoded on nuclear DNA, translated on cytosolic ribosomes and imported into their target organelles by a dedicated machinery. Recent studies have provided insights into the import into the organelles and the membrane insertion of these proteins. Although the cytosolic stages of their biogenesis are less well defined, it is speculated that upon their synthesis, chaperones prevent β-barrel proteins from aggregation and keep them in an import-competent conformation. In this Review, we summarize the current knowledge about the biogenesis of β-barrel proteins, focusing on the early stages from the translation on cytosolic ribosomes to the recognition on the surface of the organelle. © 2017 Federation of European Biochemical Societies.

Comparative responses to endocrine disrupting compounds in early life stages of Atlantic salmon, Salmo salar

USGS Publications Warehouse

Duffy, Tara A.; Iwanowicz, Luke R.; McCormick, Stephen D.

2014-01-01

Atlantic salmon (Salmo salar) are endangered anadromous fish that may be exposed to feminizing endocrine disrupting compounds (EDCs) during early development, potentially altering physiological capacities, survival and fitness. To assess differential life stage sensitivity to common EDCs, we carried out short-term (four day) exposures using three doses each of 17α-ethinylestradiol (EE2), 17β-estradiol (E2), and nonylphenol (NP) on four early life stages; embryos, yolk-sac larvae, feeding fry and one year old smolts. Differential response was compared using vitellogenin (Vtg, a precursor egg protein) gene transcription. Smolts were also examined for impacts on plasma Vtg, cortisol, thyroid hormones (T4/T3) and hepatosomatic index (HSI). Compound-related mortality was not observed in any life stage, but Vtg mRNA was elevated in a dose-dependent manner in yolk-sac larvae, fry and smolts but not in embyos. The estrogens EE2 and E2 were consistently stronger inducers of Vtg than NP. Embryos responded significantly to the highest concentration of EE2 only, while older life stages responded to the highest doses of all three compounds, as well as intermediate doses of EE2 and E2. Maximal transcription was greater for fry among the three earliest life stages, suggesting fry may be the most responsive life stage in early development. Smolt plasma Vtg was also significantly increased, and this response was observed at lower doses of each compound than was detected by gene transcription suggesting this is a more sensitive indicator at this life stage. HSI was increased at the highest doses of EE2 and E2 and plasma T3 decreased at the highest dose of EE2. Our results indicate that all life stages after hatching are potentially sensitive to endocrine disruption by estrogenic compounds and that physiological responses were altered over a short window of exposure, indicating the potential for these compounds to impact fish in the wild.

Comparative responses to endocrine disrupting compounds in early life stages of Atlantic salmon, Salmo salar.

PubMed

Duffy, T A; Iwanowicz, L R; McCormick, S D

2014-07-01

Atlantic salmon (Salmo salar) are endangered anadromous fish that may be exposed to feminizing endocrine disrupting compounds (EDCs) during early development, potentially altering physiological capacities, survival and fitness. To assess differential life stage sensitivity to common EDCs, we carried out short-term (4 day) exposures using three doses each of 17 α-ethinylestradiol (EE2), 17 β-estradiol (E2), and nonylphenol (NP) on four early life stages; embryos, yolk-sac larvae, feeding fry and 1 year old smolts. Differential response was compared using vitellogenin (Vtg, a precursor egg protein) gene transcription. Smolts were also examined for impacts on plasma Vtg, cortisol, thyroid hormones (T4/T3) and hepatosomatic index (HSI). Compound-related mortality was not observed in any life stage, but Vtg mRNA was elevated in a dose-dependent manner in yolk-sac larvae, fry and smolts but not in embryos. The estrogens EE2 and E2 were consistently stronger inducers of Vtg than NP. Embryos responded significantly to the highest concentration of EE2 only, while older life stages responded to the highest doses of all three compounds, as well as intermediate doses of EE2 and E2. Maximal transcription was greater for fry among the three earliest life stages, suggesting fry may be the most responsive life stage in early development. Smolt plasma Vtg was also significantly increased, and this response was observed at lower doses of each compound than was detected by gene transcription suggesting plasma Vtg is a more sensitive indicator at this life stage. HSI was increased at the highest doses of EE2 and E2, and plasma T3 was decreased at the highest dose of EE2. Our results indicate that all life stages are potentially sensitive to endocrine disruption by estrogenic compounds and that physiological responses were altered over a short window of exposure, indicating the potential for these compounds to impact fish in the wild. Copyright © 2014 Elsevier B.V. All rights

3-Nitrotyrosine and glutathione antioxidant system in patients in the early and late stages of bipolar disorder

PubMed Central

Andreazza, Ana Cristina; Kapczinski, Flavio; Kauer-Sant’Anna, Marcia; Walz, Julio C.; Bond, David J.; Gonçalves, Carlos A.; Young, L. Trevor; Yatham, Lakshmi N.

2009-01-01

Background There has been an increasing interest in the role of oxidative stress in the pathophysiology of bipolar disorder. To explore this further, we evaluated the activity of glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione S-transferase (GST), as well as 3-nitrotyrosine levels and carbonyl content in patients in the early (within 3 years of illness onset) and late (a minimum of 10 years of illness) stages of bipolar disorder. Methods We matched 30 patients in the early stage and 30 patients in the late stage of bipolar disorder, diagnosed according to DSM-IV criteria, with 60 healthy controls (30 matched for each group of patients). We measured symptomatic status using the Hamilton Rating Scale for Depression and the Young Mania Rating Scale. Results We found a significant increase in 3-nitrotyrosine levels among patients in the early (p < 0.010) and late (p < 0.010) stages of bipolar disorder. The activity of GR and GST was increased only among patients in the late stage of illness. Glutathione peroxidase activity and carbonyl content did not differ among the groups. Limitations Limitations of our study include its cross-sectional design, which did not allow us to examine direct causative mechanisms or the effects of progression of illness, and the potential environmental bias introduced by comparing patient groups recruited from different regions of the world. Conclusion Our data indicate a possible tyrosine nitration-induced damage in patients with bipolar disorder that is present from the early stage of illness. Our data also indicate that patients in the late stage of illness demonstrate enhanced activity of GR and GST, which could suggest the involvement of a compensatory system in bipolar disorder. PMID:19568477

Fibroblast growth factor 23, iron and inflammation - are they related in early stages of chronic kidney disease?

PubMed

Lukaszyk, Ewelina; Lukaszyk, Mateusz; Koc-Zorawska, Ewa; Bodzenta-Lukaszyk, Anna; Malyszko, Jolanta

2017-06-01

Fibroblast growth factor 23 (FGF-23) levels are elevated in impaired renal function. Inflammation and iron are potential regulators of FGF-23. The aim of the study was to evaluate the association between FGF-23 concentration, novel iron status biomarkers and inflammatory parameters among patients with early stages of chronic kidney disease (CKD). The study population included 84 patients with CKD in the early stage. Serum hemoglobin, fibrinogen, creatinine, iron, transferrin saturation and ferritin levels were measured using standard laboratory methods. Commercially available kits were used to measure: intact FGF-23, hepcidin, soluble transferrin receptor (sTfR), interleukin 6 (IL-6) and high-sensitivity C-reactive protein (hsCRP). In patients with CKD no differences in FGF-23 concentration according to iron status were observed. Lower iron concentration was associated with higher concentrations of hsCRP, IL-6 and fibrinogen. In univariate and multivariate analysis FGF-23 correlated with fibrinogen ( r = -0.23, p < 0.05) and eGFR ( r = -0.36, p < 0.05). FGF-23 is affected by kidney function and fibrinogen but not iron status parameters in the early stages of CKD. Our data are paving the way for further studies on the role of FGF-23 in iron metabolism, especially in early stages of CKD.

Developmental toxicity of PAH mixtures in fish early life stages. Part II: adverse effects in Japanese medaka.

PubMed

Le Bihanic, Florane; Clérandeau, Christelle; Le Menach, Karyn; Morin, Bénédicte; Budzinski, Hélène; Cousin, Xavier; Cachot, Jérôme

2014-12-01

In aquatic environments, polycyclic aromatic hydrocarbons (PAHs) mostly occur as complex mixtures, for which risk assessment remains problematic. To better understand the effects of PAH mixture toxicity on fish early life stages, this study compared the developmental toxicity of three PAH complex mixtures. These mixtures were extracted from a PAH-contaminated sediment (Seine estuary, France) and two oils (Arabian Light and Erika). For each fraction, artificial sediment was spiked at three different environmental concentrations roughly equivalent to 0.5, 4, and 10 μg total PAH g(-1) dw. Japanese medaka embryos were incubated on these PAH-spiked sediments throughout their development, right up until hatching. Several endpoints were recorded at different developmental stages, including acute endpoints, morphological abnormalities, larvae locomotion, and genotoxicity (comet and micronucleus assays). The three PAH fractions delayed hatching, induced developmental abnormalities, disrupted larvae swimming activity, and damaged DNA at environmental concentrations. Differences in toxicity levels, likely related to differences in PAH proportions, were highlighted between fractions. The Arabian Light and Erika petrogenic fractions, containing a high proportion of alkylated PAHs and low molecular weight PAHs, were more toxic to Japanese medaka early life stages than the pyrolytic fraction. This was not supported by the toxic equivalency approach, which appeared unsuitable for assessing the toxicity of the three PAH fractions to fish early life stages. This study highlights the potential risks posed by environmental mixtures of alkylated and low molecular weight PAHs to early stages of fish development.

Mitochondrial Epigenetic Changes Link to Increased Diabetes Risk and Early-Stage Prediabetes Indicator

PubMed Central

Zheng, Louise D.; Linarelli, Leah E.; Brooke, Joseph; Smith, Cayleen; Wall, Sarah S.; Greenawald, Mark H.; Seidel, Richard W.; Estabrooks, Paul A.; Almeida, Fabio A.; Cheng, Zhiyong

2016-01-01

Type 2 diabetes (T2D) is characterized by mitochondrial derangement and oxidative stress. With no known cure for T2D, it is critical to identify mitochondrial biomarkers for early diagnosis of prediabetes and disease prevention. Here we examined 87 participants on the diagnosis power of fasting glucose (FG) and hemoglobin A1c levels and investigated their interactions with mitochondrial DNA methylation. FG and A1c led to discordant diagnostic results irrespective of increased body mass index (BMI), underscoring the need of new biomarkers for prediabetes diagnosis. Mitochondrial DNA methylation levels were not correlated with late-stage (impaired FG or A1c) but significantly with early-stage (impaired insulin sensitivity) events. Quartiles of BMI suggested that mitochondrial DNA methylation increased drastically from Q1 (20 < BMI < 24.9, lean) to Q2 (30 < BMI < 34.9, obese), but marginally from Q2 to Q3 (35 < BMI < 39.9, severely obese) and from Q3 to Q4 (BMI > 40, morbidly obese). A significant change was also observed from Q1 to Q2 in HOMA insulin sensitivity but not in A1c or FG. Thus, mitochondrial epigenetic changes link to increased diabetes risk and the indicator of early-stage prediabetes. Further larger-scale studies to examine the potential of mitochondrial epigenetic marker in prediabetes diagnosis will be of critical importance for T2D prevention. PMID:27298712

Mapping thalamocortical functional connectivity in chronic and early stages of psychotic disorders

PubMed Central

Woodward, Neil D.; Heckers, Stephan

2015-01-01

Objective There is considerable evidence that the thalamus is abnormal in psychotic disorders. Resting-state fMRI (RS-fMRI) has revealed an intriguing pattern of thalamic dysconnectivity in psychosis characterized by reduced prefrontal cortex (PFC) connectivity and increased somatomotor-thalamic connectivity. However, critical knowledge gaps remain with respect to the onset, anatomical specificity, and clinical correlates of thalamic dysconnectivity in psychosis. Method RS-fMRI was collected on 105 healthy subjects and 148 individuals with psychosis, including 53 early stage psychosis patients. Using all 253 subjects, the thalamus was parceled into functional regions-of-interest (ROIs) on the basis of connectivity with six a-priori defined cortical ROIs covering most of the cortical mantle. Functional connectivity between each cortical ROI and its corresponding thalamic ROI was quantified and compared across groups. Significant differences in the ROI-to-ROI analysis were followed up with voxel-wise seed-based analyses to further localize thalamic dysconnectivity. Results ROI analysis revealed reduced PFC-thalamic connectivity and increased somatomotor-thalamic connectivity in both chronic and early stages psychosis patients. PFC hypo-connectivity and motor cortex hyper-connectivity correlated in patients suggesting they result from a common pathophysiological mechanism. Seed-based analyses revealed thalamic hypo-connectivity in psychosis localized to dorsolateral PFC, medial PFC, and cerebellar areas of the well-described ‘executive control’ network. Across all subjects, thalamic connectivity with areas of the fronto-parietal network correlated with cognitive functioning, including verbal learning and memory. Conclusions Thalamocortical dysconnectivity is present in both chronic and early stages of psychosis, includes reduced thalamic connectivity with the executive control network, and is related to cognitive impairment. PMID:26248537

Hydrodynamic instability of elastic-plastic solid plates at the early stage of acceleration.

PubMed

Piriz, A R; Sun, Y B; Tahir, N A

2015-03-01

A model is presented for the linear Rayleigh-Taylor instability taking place at the early stage of acceleration of an elastic-plastic solid, when the shock wave is still running into the solid and is driven by a time varying pressure on the interface. When the the shock is formed sufficiently close to the interface, this stage is considered to follow a previous initial phase controlled by the Ritchmyer-Meshkov instability that settles new initial conditions. The model reproduces the behavior of the instability observed in former numerical simulation results and provides a relatively simpler physical picture than the currently existing one for this stage of the instability evolution.

Early stages of zeolite growth

NASA Astrophysics Data System (ADS)

Kumar, Sandeep

Zeolites are crystalline nonporous aluminosilicates with important applications in separation, purification, and adsorption of liquid and gaseous molecules. However, an ability to tailor the zeolite microstructure, such as particle size/shape and pore-size, to make it benign for specific application requires control over nucleation and particle growth processes. But, the nucleation and crystallization mechanisms of zeolites are not fully understood. In this context, the synthesis of an all-silica zeolite with MFI-type framework has been studied extensively as a model system. Throughout chapters 2, 4 and 5, MFI growth process has been investigated by small-angle x-ray scattering (SAXS) and transmission electron microscopy (TEM). Of fundamental importance is the role of nanoparticles (~5 nm), which are present in the precursor sol, in MFI nucleation and crystallization. Formation of amorphous aggregates and their internal restructuring are concluded as essential steps in MFI nucleation. Early stage zeolite particles have disordered and less crystalline regions within, which indicates the role of structurally distributed population of nanoparticles in growth. Faceting occurs after the depletion of nanoparticles. The chapter 6 presents growth studies in silica sols prepared by using a dimer of tertaprpylammonium (TPA) and reports that MFI nucleation and crystallization are delayed with a more pronounced delay in crystal growth.

The temporal characteristics of the early and late stages of the L- and M-cone pathways that signal color

PubMed Central

Petrova, Daniela; Henning, G. Bruce; Stockman, Andrew

2013-01-01

Flickering long-wavelength light appears more yellow than steady light of the same average intensity. The hue change is consistent with distortion of the visual signal at some nonlinear site (or sites) that produces temporal components not present in the original stimulus (known as distortion products). We extracted the temporal attenuation characteristics of the early (prenonlinearity) and late (post-nonlinearity) filter stages in the L- and M-cone chromatic pathway by varying the input stimulus to manipulate the distortion products and the measuring of the observers' sensitivity to them. The early, linear, filter stage acts like a band-pass filter peaking at 10–15 Hz with substantial sensitivity losses at both lower and higher frequencies. Its characteristics are consistent with nonlinearity being early in the visual pathway but following surround inhibition. The late stage, in contrast, acts like a low-pass filter with a cutoff frequency around 3 Hz. The response of the early stage speeds up with radiance, but the late stage does not. A plausible site for the nonlinearity, which modelling suggests may be smoothly compressive but with a hard limit at high input levels, is after surround inhibition from the horizontal cells. PMID:23457358

A Prospectus on Restoring Late Successional Forest Structure to Eastside Pine Ecosystems Through Large-Scale, Interdisciplinary Research

Treesearch

Steve Zack; William F. Laudenslayer; Luke George; Carl Skinner; William Oliver

1999-01-01

At two different locations in northeast California, an interdisciplinary team of scientists is initiating long-term studies to quantify the effects of forest manipulations intended to accelerate andlor enhance late-successional structure of eastside pine forest ecosystems. One study, at Blacks Mountain Experimental Forest, uses a split-plot, factorial, randomized block...

Socioeconomic Factors Are Associated With Readmission After Lobectomy for Early Stage Lung Cancer.

PubMed

Medbery, Rachel L; Gillespie, Theresa W; Liu, Yuan; Nickleach, Dana C; Lipscomb, Joseph; Sancheti, Manu S; Pickens, Allan; Force, Seth D; Fernandez, Felix G

2016-11-01

Data regarding risk factors for readmissions after surgical resection for lung cancer are limited and largely focus on postoperative outcomes, including complications and hospital length of stay. The current study aims to identify preoperative risk factors for postoperative readmission in early stage lung cancer patients. The National Cancer Data Base was queried for all early stage lung cancer patients with clinical stage T2N0M0 or less who underwent lobectomy in 2010 and 2011. Patients with unplanned readmission within 30 days of hospital discharge were identified. Univariate analysis was utilized to identify preoperative differences between readmitted and not readmitted cohorts; multivariable logistic regression was used to identify risk factors resulting in readmission. In all, 840 of 19,711 patients (4.3%) were readmitted postoperatively. Male patients were more likely to be readmitted than female patients (4.9% versus 3.8%, p < 0.001), as were patients who received surgery at a nonacademic rather than an academic facility (4.6% versus 3.6%; p = 0.001) and had underlying medical comorbidities (Charlson/Deyo score 1+ versus 0; 4.8% versus 3.7%; p < 0.001). Readmitted patients had a longer median hospital length of stay (6 days versus 5; p < 0.001) and were more likely to have undergone a minimally invasive approach (5.1% video-assisted thoracic surgery versus 3.9% open; p < 0.001). In addition to those variables, multivariable logistic regression analysis identified that median household income level, insurance status (government versus private), and geographic residence (metropolitan versus urban versus rural) had significant influence on readmission. The socioeconomic factors identified significantly influence hospital readmission and should be considered during preoperative and postoperative discharge planning for patients with early stage lung cancer. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Trastuzumab in early stage breast cancer: a cost-effectiveness analysis for Belgium.

PubMed

Neyt, Mattias; Huybrechts, Michel; Hulstaert, Frank; Vrijens, France; Ramaekers, Dirk

2008-08-01

Although trastuzumab is traditionally used in metastatic breast cancer treatment, studies reported on the efficacy and safety of trastuzumab in adjuvant setting for the treatment of early stage breast cancer in HER2+ tumors. We estimated the cost-effectiveness and budget impact of reimbursing trastuzumab in this indication from a payer's perspective. We constructed a health economic model. Long-term consequences of preventing patients to progress to metastatic breast cancer and side effects such as congestive heart failure were taken into account. Uncertainty was handled applying probabilistic modeling and through probabilistic sensitivity analyses. In the HERA scenario, applying an arbitrary threshold of euro30000 per life-year gained, early stage breast cancer treatment with trastuzumab is cost-effective for 9 out of 15 analyzed subgroups (according to age and stage). In contrast, treatment according to the FinHer scenario is cost-effective in 14 subgroups. Furthermore, the FinHer regimen is most of the times cost saving with an average incremental cost of euro668, euro-1045, and euro-6869 for respectively stages I, II and III breast cancer patients whereas the HERA regimen is never cost saving due to the higher initial treatment costs. The model shows better cost-effectiveness for the 9-week initial treatment (FinHer) compared to no trastuzumab treatment than for the 1-year post-chemotherapy treatment (HERA). Both from a medical and an economic point of view, the 9-week initial treatment regimen with trastuzumab shows promising results and justifies the initiation of a large comparative trial with a 1-year regimen.

The effects of parasites on the early life stages of a damselfish

NASA Astrophysics Data System (ADS)

Sun, D.; Blomberg, S. P.; Cribb, T. H.; McCormick, M. I.; Grutter, A. S.

2012-12-01

Early life history traits, such as larval growth, influence the success of coral reef fish in the transition from the larval to the juvenile life phase. Few studies, however, have examined the relationship between parasites and growth in the early life history stages of such fishes. This study examined how parasite prevalence (% infected) and load, and the relationship between parasite presence and fish growth, differed among life stages of the damselfish Pomacentrus amboinensis. Parasite prevalence decreased significantly between the larval stage, which was sampled immediately before settlement on the reef (97 %) and recently settled juveniles (60 %); prevalence was also high for 4-month-old juveniles (90 %), 7-month-old juveniles (100 %) and adult fish (100 %). Total numbers of parasites per fish decreased dramatically (fourfold) between larval and recently settled fish, and then increased in the older stages to levels similar to those observed in larvae, but they did so more gradually than did prevalence. One explanation for these patterns is that heavily infected larvae were preferentially removed from the population during or soon after settlement. Daily fish growth, determined from otolith increments, revealed that growth did not differ between parasitised and non-parasitised larval fish, whereas recently settled fish that were parasitised had faster growth; these parasitised recently settled fish also displayed faster growth prior to settlement. These data provide evidence that parasites may explain some of the variation in growth and survival observed among coral reef fishes after settlement and thereby have a greater impact on population dynamics than previously understood.

SU-F-R-24: Identifying Prognostic Imaging Biomarkers in Early Stage Lung Cancer Using Radiomics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeng, X; Wu, J; Cui, Y

2016-06-15

Purpose: Patients diagnosed with early stage lung cancer have favorable outcomes when treated with surgery or stereotactic radiotherapy. However, a significant proportion (∼20%) of patients will develop metastatic disease and eventually die of the disease. The purpose of this work is to identify quantitative imaging biomarkers from CT for predicting overall survival in early stage lung cancer. Methods: In this institutional review board-approved HIPPA-compliant retrospective study, we retrospectively analyzed the diagnostic CT scans of 110 patients with early stage lung cancer. Data from 70 patients were used for training/discovery purposes, while those of remaining 40 patients were used for independentmore » validation. We extracted 191 radiomic features, including statistical, histogram, morphological, and texture features. Cox proportional hazard regression model, coupled with the least absolute shrinkage and selection operator (LASSO), was used to predict overall survival based on the radiomic features. Results: The optimal prognostic model included three image features from the Law’s feature and wavelet texture. In the discovery cohort, this model achieved a concordance index or CI=0.67, and it separated the low-risk from high-risk groups in predicting overall survival (hazard ratio=2.72, log-rank p=0.007). In the independent validation cohort, this radiomic signature achieved a CI=0.62, and significantly stratified the low-risk and high-risk groups in terms of overall survival (hazard ratio=2.20, log-rank p=0.042). Conclusion: We identified CT imaging characteristics associated with overall survival in early stage lung cancer. If prospectively validated, this could potentially help identify high-risk patients who might benefit from adjuvant systemic therapy.« less

Prognostic value of periostin in early-stage breast cancer treated with conserving surgery and radiotherapy.

PubMed

Li, Changyou; Xu, Jing; Wang, Qi; Geng, Shaoqing; Yan, Zheng; You, Jin; Li, Zhenfeng; Zou, Xiao

2018-05-01

The present study was performed to explore the prognostic significance of periostin expression in a cohort of patients with early-stage breast cancer treated with breast conserving surgery following radiotherapy. A tissue microarray of tumor samples from 259 patients with early-stage breast cancer was assayed for periostin, estrogen receptor (ER), progesterone receptor (PR), ErbB2 receptor tyrosine kinase 2 and Ki-67 expression by immunohistochemistry. The association of periostin with other clinicopathological parameters and clinical outcomes, including local recurrence free survival (RFS), distant metastasis free survival (DFS) and overall survival (OS), were assessed through log-rank tests and univariate and multivariate analysis. Periostin expression was identified in 91 of the 259 tissue samples (35%). The periostin status was significantly associated with histological grade (P=0.001), nodal status (P=0.023), molecular subtype (P<0.01), ER status (P<0.01), PR status (P<0.01) and Ki-67 expression (P=0.011). Furthermore, periostin expression was associated with an increased risk of five-year local recurrence (95.8% vs. 89.0%; P=0.017) and distant metastasis (92.3% vs. 79.1%; P=0.001) in patients with early stage breast cancer. Multivariate analysis using Cox's proportional hazards model demonstrated that periostin expression was an independent predictor of all clinical outcomes in breast cancer (RFS, P=0.018; DFS, P=0.025; OS, P=0.047). Therefore, it was concluded that periostin is associated with an increased risk of local relapse and distant metastasis in early-stage breast cancer treated with conserving surgery and radiotherapy. This association should be further investigated in larger cohorts to validate the clinical significance of periostin expression.

On the role of extracellular polymeric substances during early stages of Xylella fastidiosa biofilm formation.

PubMed

Lorite, Gabriela S; de Souza, Alessandra A; Neubauer, Daniel; Mizaikoff, Boris; Kranz, Christine; Cotta, Mônica A

2013-02-01

The structural integrity and protection of bacterial biofilms are intrinsically associated with a matrix of extracellular polymeric substances (EPS) produced by the bacteria cells. However, the role of these substances during biofilm adhesion to a surface remains largely unclear. In this study, the influence of EPS on Xylella fastidiosa biofilm formation was investigated. This bacterium is associated with economically important plant diseases; it presents a slow growth rate and thus allows us to pinpoint more precisely the early stages of cell-surface adhesion. Scanning electron microscopy and atomic force microscopy show evidence of EPS production in such early stages and around individual bacteria cells attached to the substrate surface even a few hours after inoculation. In addition, EPS formation was investigated via attenuated total reflectance (ATR) Fourier transform infrared spectroscopy (FTIR). To this end, X. fastidiosa cells were inoculated within an ATR liquid cell assembly. IR-ATR spectra clearly reveal EPS formation already during the early stages of X. fastidiosa biofilm formation, thereby providing supporting evidence for the hypothesis of the relevance of the EPS contribution to the adhesion process. Copyright © 2012 Elsevier B.V. All rights reserved.

Finite element simulation of ultrasonic waves in corroded reinforced concrete for early-stage corrosion detection

NASA Astrophysics Data System (ADS)

Tang, Qixiang; Yu, Tzuyang

2017-04-01

In reinforced concrete (RC) structures, corrosion of steel rebar introduces internal stress at the interface between rebar and concrete, ultimately leading to debonding and separation between rebar and concrete. Effective early-stage detection of steel rebar corrosion can significantly reduce maintenance costs and enable early-stage repair. In this paper, ultrasonic detection of early-stage steel rebar corrosion inside concrete is numerically investigated using the finite element method (FEM). Commercial FEM software (ABAQUS) was used in all simulation cases. Steel rebar was simplified and modeled by a cylindrical structure. 1MHz ultrasonic elastic waves were generated at the interface between rebar and concrete. Two-dimensional plain strain element was adopted in all FE models. Formation of surface rust in rebar was modeled by changing material properties and expanding element size in order to simulate the rust interface between rebar and concrete and the presence of interfacial stress. Two types of surface rust (corroded regions) were considered. Time domain and frequency domain responses of displacement were studied. From our simulation result, two corrosion indicators, baseline (b) and center frequency (fc) were proposed for detecting and quantifying corrosion.

HMGCR inhibits the early stage of PCV2 infection, while PKC enhances the infection at the late stage.

PubMed

Ma, Teng; Chen, Xinrong; Ouyang, Hongsheng; Liu, Xiaohui; Ouyang, Ting; Peng, Zhiyuan; Yang, Xin; Chen, Fuwang; Pang, Daxin; Bai, Jieying; Ren, Linzhu

2017-02-02

Porcine circovirus type 2 (PCV2) is the smallest DNA virus, which causes porcine circovirus diseases and porcine circovirus-associated diseases (PCVD/PCVAD). Due the small size of viral genomic DNA, PCV2 replication predominantly relies on the host factors. In this study, effects of PKC and HMGCR on PCV2 infection were evaluated using real time PCR and western blot. We found that PKC and HMGCR participated in different stages of PCV2 infection. HMGCR works on the early stage of the infection to inhibit the virus infection, while PKC enhances the infection at the late stage. Furthermore, PKC enhances PCV2 replication by activating JNK1/2 and inactivating HMGCR via regulating phosphorylation of these two proteins, while HMGCR can suppress phosphorylation of JNK1/2. The results in the present study will provide new sights in the pathogenesis of PCV2 infection, as well as interactions between host factors during PCV2 infection. Copyright © 2016 Elsevier B.V. All rights reserved.

Sleep Characteristics in Early Stages of Chronic Kidney Disease in the HypnoLaus Cohort.

PubMed

Ogna, Adam; Forni Ogna, Valentina; Haba Rubio, José; Tobback, Nadia; Andries, Dana; Preisig, Martin; Tafti, Mehdi; Vollenweider, Peter; Waeber, Gerard; Marques-Vidal, Pedro; Heinzer, Raphaël

2016-04-01

To evaluate the association between early stages of chronic kidney disease (CKD) and sleep disordered breathing (SDB), restless legs syndrome (RLS), and subjective and objective sleep quality (SQ). Cross-sectional analysis of a general population-based cohort (HypnoLaus). 1,760 adults (862 men, 898 women; age 59.3 (± 11.4) y) underwent complete polysomnography at home. 8.2% of participants had mild CKD (stage 1-2, estimated glomerular filtration rate [eGFR] ≥ 60 mL/min/1.73 m(2) with albuminuria) and 7.8% moderate CKD (stage 3, eGFR 30-60 mL/min/1.73 m(2)). 37.3% of our sample had moderate-to-severe SDB (apnea-hypopnea index [AHI] ≥ 15/h) and 15.3% had severe SDB (AHI ≥ 30/h). SDB prevalence was positively associated with CKD stages and negatively with eGFR. In multivariate analysis, age, male sex, and body mass index were independently associated with SDB (all P < 0.001), but kidney function was not. The prevalence of RLS was 17.5%, without difference between CKD stages. Periodic leg movements index (PLMI) was independently associated with CKD stages. Subjective and objective SQ decreased and the use of sleep medication was more frequent with declining kidney function. Older age, female sex, and the severity of SDB were the strongest predictors of poor SQ in multivariate regression analysis but CKD stage was also independently associated with reduced objective SQ. Patients with early stages of CKD have impaired SQ, use more hypnotic drugs, and have an increased prevalence of SDB and PLM. After controlling for confounders, objective SQ and PLMI were still independently associated with declining kidney function. © 2016 Associated Professional Sleep Societies, LLC.

The Impact of Global Warming and Anoxia on Marine Benthic Community Dynamics: an Example from the Toarcian (Early Jurassic)

PubMed Central

Danise, Silvia; Twitchett, Richard J.; Little, Crispin T. S.; Clémence, Marie-Emilie

2013-01-01

The Pliensbachian-Toarcian (Early Jurassic) fossil record is an archive of natural data of benthic community response to global warming and marine long-term hypoxia and anoxia. In the early Toarcian mean temperatures increased by the same order of magnitude as that predicted for the near future; laminated, organic-rich, black shales were deposited in many shallow water epicontinental basins; and a biotic crisis occurred in the marine realm, with the extinction of approximately 5% of families and 26% of genera. High-resolution quantitative abundance data of benthic invertebrates were collected from the Cleveland Basin (North Yorkshire, UK), and analysed with multivariate statistical methods to detect how the fauna responded to environmental changes during the early Toarcian. Twelve biofacies were identified. Their changes through time closely resemble the pattern of faunal degradation and recovery observed in modern habitats affected by anoxia. All four successional stages of community structure recorded in modern studies are recognised in the fossil data (i.e. Stage III: climax; II: transitional; I: pioneer; 0: highly disturbed). Two main faunal turnover events occurred: (i) at the onset of anoxia, with the extinction of most benthic species and the survival of a few adapted to thrive in low-oxygen conditions (Stages I to 0) and (ii) in the recovery, when newly evolved species colonized the re-oxygenated soft sediments and the path of recovery did not retrace of pattern of ecological degradation (Stages I to II). The ordination of samples coupled with sedimentological and palaeotemperature proxy data indicate that the onset of anoxia and the extinction horizon coincide with both a rise in temperature and sea level. Our study of how faunal associations co-vary with long and short term sea level and temperature changes has implications for predicting the long-term effects of “dead zones” in modern oceans. PMID:23457537

The impact of global warming and anoxia on marine benthic community dynamics: an example from the Toarcian (Early Jurassic).

PubMed

Danise, Silvia; Twitchett, Richard J; Little, Crispin T S; Clémence, Marie-Emilie

2013-01-01

The Pliensbachian-Toarcian (Early Jurassic) fossil record is an archive of natural data of benthic community response to global warming and marine long-term hypoxia and anoxia. In the early Toarcian mean temperatures increased by the same order of magnitude as that predicted for the near future; laminated, organic-rich, black shales were deposited in many shallow water epicontinental basins; and a biotic crisis occurred in the marine realm, with the extinction of approximately 5% of families and 26% of genera. High-resolution quantitative abundance data of benthic invertebrates were collected from the Cleveland Basin (North Yorkshire, UK), and analysed with multivariate statistical methods to detect how the fauna responded to environmental changes during the early Toarcian. Twelve biofacies were identified. Their changes through time closely resemble the pattern of faunal degradation and recovery observed in modern habitats affected by anoxia. All four successional stages of community structure recorded in modern studies are recognised in the fossil data (i.e. Stage III: climax; II: transitional; I: pioneer; 0: highly disturbed). Two main faunal turnover events occurred: (i) at the onset of anoxia, with the extinction of most benthic species and the survival of a few adapted to thrive in low-oxygen conditions (Stages I to 0) and (ii) in the recovery, when newly evolved species colonized the re-oxygenated soft sediments and the path of recovery did not retrace of pattern of ecological degradation (Stages I to II). The ordination of samples coupled with sedimentological and palaeotemperature proxy data indicate that the onset of anoxia and the extinction horizon coincide with both a rise in temperature and sea level. Our study of how faunal associations co-vary with long and short term sea level and temperature changes has implications for predicting the long-term effects of "dead zones" in modern oceans.

Goal-oriented cognitive rehabilitation in early-stage dementia: study protocol for a multi-centre single-blind randomised controlled trial (GREAT)

PubMed Central

2013-01-01

Background Preliminary evidence suggests that goal-oriented cognitive rehabilitation (CR) may be a clinically effective intervention for people with early-stage Alzheimer’s disease, vascular or mixed dementia and their carers. This study aims to establish whether CR is a clinically effective and cost-effective intervention for people with early-stage dementia and their carers. Methods/design In this multi-centre, single-blind randomised controlled trial, 480 people with early-stage dementia, each with a carer, will be randomised to receive either treatment as usual or cognitive rehabilitation (10 therapy sessions over 3 months, followed by 4 maintenance sessions over 6 months). We will compare the effectiveness of cognitive rehabilitation with that of treatment as usual with regard to improving self-reported and carer-rated goal performance in areas identified as causing concern by people with early-stage dementia; improving quality of life, self-efficacy, mood and cognition of people with early-stage dementia; and reducing stress levels and ameliorating quality of life for carers of participants with early-stage dementia. The incremental cost-effectiveness of goal-oriented cognitive rehabilitation compared to treatment as usual will also be examined. Discussion If the study confirms the benefits and cost-effectiveness of cognitive rehabilitation, it will be important to examine how the goal-oriented cognitive rehabilitation approach can most effectively be integrated into routine health-care provision. Our aim is to provide training and develop materials to support the implementation of this approach following trial completion. Trial registration Current Controlled Trials ISRCTN21027481 PMID:23710796

Increasing fire severity, alternate successional trajectories, and the carbon balance of Alaskan boreal forests

NASA Astrophysics Data System (ADS)

Mack, M. C.; Alexander, H. D.; Jean, M.; Melvin, A. M.; Johnstone, J. F.

2016-12-01

Climate-sensitive disturbances, such as wildfire, can feed back positively to climate warming via the carbon (C) cycle if C released by disturbance is not replaced over post-fire succession. In boreal forests, burning of carbon in deep organic soils is not only an important determinate of ecosystem element balance over the disturbance cycle, but also sets the conditions that control plant recruitment, species dominance and successional trajectory. Species dominance, in turn, has the potential to exert strong control over the plant-soil-microbial feedbacks that determine C and nutrient coupling, C storage, and ultimately, replacement of combusted C. We examined the consequences of increasing fire severity for C balance and C and nitrogen (N) coupling in Alaskan boreal forests. We estimated combustion losses in 90 black spruce (conifer) stands that burned in 2004. Over the next decade, we followed natural tree seedling establishment in these stands and used seedling species dominance identify conifer versus deciduous successional trajectories. We assembled data from 120 stands that varied in time after fire and successional trajectory, and estimated C and N dynamics across 150 years of post-fire succession for each trajectory. Conifer stands that burned with high severity transitioned to deciduous tree dominance after fire. These stands had smaller ecosystem pools of C and N before fire, lost a larger proportion of these pools during the fire, and began succession with smaller residual pools than stands that returned to conifer dominance after fire. Over secondary succession, deciduous stands accumulated about 10 times more carbon in aboveground biomass than conifer stands. Belowground biomass and soil carbon accumulation, by contrast, was about three times higher in the black spruce stands than in deciduous stands. As a result, net ecosystem C accumulation over the 100 year inter-fire interval was three times higher in deciduous stands than in coniferous stands

Low-Dose Consolidation Radiation Therapy for Early Stage Unfavorable Hodgkin Lymphoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Torok, Jordan A., E-mail: jordan.torok@dm.duke.edu; Wu, Yuan; Prosnitz, Leonard R.

Purpose: The German Hodgkin Study Group (GHSG) trial HD11 established 4 cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) and 30 Gy of radiation therapy (RT) as a standard for early stage (I, II), unfavorable Hodgkin lymphoma (HL). Additional cycles of ABVD may allow for a reduction in RT dose and improved toxicity profile. Methods and Materials: Patients treated with combined modality therapy at the Duke Cancer Institute for early stage, unfavorable HL by GHSG criteria from 1994 to 2012 were included. Patients who did not undergo post-chemotherapy functional imaging (positron emission tomography or gallium imaging) or who failed to achievemore » a complete response were excluded. Clinical outcomes were estimated using the Kaplan-Meier method. Late effects were also evaluated. Results: A total of 90 patients met inclusion criteria for analysis. Median follow-up was 5 years. Chemotherapy consisted primarily of ABVD (88%) with a median number of 6 cycles. The median dose of consolidation RT was 23.4 Gy. Four patients had relapses, 2 of which were in-field. Ten-year progression-free survival (PFS) and overall survival (OS) were 93% (95% confidence interval [CI]: 0.82-0.97) and 98% (95% CI: 0.92-0.99), respectively. For the subset of patients (n=46) who received 5 to 6 cycles of chemotherapy and ≤24 Gy, the 10-year PFS and OS values were 88% (95% CI: 70%-96%) and 98% (95% CI: 85% - 99%), respectively. The most common late effect was hypothyroidism (20%) with no cardiac complications. Seven secondary malignancies were diagnosed, with only 1 arising within the RT field. Conclusions: Lower doses of RT may be sufficient when combined with more than 4 cycles of ABVD for early stage, unfavorable HL and may result in a more favorable toxicity profile than 4 cycles of ABVD and 30 Gy of RT.« less

Histopathological diagnosis of acral lentiginous melanoma in early stages.

PubMed

Fernandez-Flores, Angel; Cassarino, David S

2017-02-01

Acral lentiginous melanoma is a rare variant of melanoma that is associated with a relatively low survival rate. The latter is partly due to the advanced stage in which the tumor is usually diagnosed. The diagnostic delay is mainly due to difficulties in identifying the very early histopathological signs of acral melanoma. The current article is a review of diagnostic clues, concepts, and definitions from the literature, as well as illustrating examples from our own archives. We have sought to provide an article that can be easily consulted in difficult cases of acral lentiginous melanoma. Copyright © 2016 Elsevier Inc. All rights reserved.

Treatment of early-stage uterine papillary serous carcinoma at Roswell Park Cancer Institute, 1992-2006.

PubMed

Tchabo, Nana E; McCloskey, Susan; Mashtare, Terry L; Andrews, Christopher; Singh, Anurag K; Mhawech-Fauceglia, Paulette; Odunsi, Kunle; Lele, Shashikant; Jaggernauth, Wainwright

2009-11-01

Optimal management of early-stage uterine papillary serous carcinoma (UPSC) remains controversial. We reviewed our outcomes in this patient population. The Roswell Park Cancer Institute (RPCI) tumor registry identified all patients with Stages I and IIA UPSC treated between January 1992 and June 2006. The Fisher's exact test was used to compare recurrence rates by adjuvant therapy received. Overall survival (OS) estimates were made using the Kaplan-Meier method. Fifty-eight patients with Stage I or IIA UPSC underwent surgery. Thirty-four patients (59%) were surgically staged. Among 21 patients with Stage IA disease, 15 received adjuvant therapy. With a median follow-up of 44.7 months, only one recurrence was observed in a patient who received adjuvant brachytherapy. The 5-year OS was 66%. Among 37 patients with Stages IB-IIA, 30 patients received adjuvant therapy. With a median follow-up of 29 months, there were 7 recurrences. The 5-year OS was 60%. Although there were no significant differences in recurrence by adjuvant therapy received, a significant OS benefit was found in those who received radiation. There was no significant difference in OS distributions of those patients who received Carboplatin/Paclitaxel chemotherapy. Despite the limitations of our retrospective study, we have shown that even comprehensively staged early-stage UPSC patients are still at risk for recurrence despite adjuvant therapy received. Hence, all patients with this histologic diagnosis should be considered at high risk for recurrence and counseled appropriately regarding the risks and benefits of adjuvant therapy.

Portfolio management in early stage drug discovery - a traveler's guide through uncharted territory.

PubMed

Betz, Ulrich A K

2011-07-01

Portfolio management in drug development has become a best practice in the pharmaceutical industry. By contrast, early on in the value chain - the discovery phase - portfolio management is still in its infancy. Nevertheless, owing to the attrition of R&D projects from phase to phase and the cost of capital involved, these early phases of drug discovery play a significant part for the overall cost of bringing new, innovative drugs to the market. This paper describes various approaches to manage a portfolio of projects in early-stage drug discovery and provides crucial factors that determine the success of such an approach. Copyright © 2011 Elsevier Ltd. All rights reserved.

Advancing Early Detection of Autism Spectrum Disorder by Applying an Integrated Two-Stage Screening Approach

ERIC Educational Resources Information Center

Oosterling, Iris J.; Wensing, Michel; Swinkels, Sophie H.; van der Gaag, Rutger Jan; Visser, Janne C.; Woudenberg, Tim; Minderaa, Ruud; Steenhuis, Mark-Peter; Buitelaar, Jan K.

2010-01-01

Background: Few field trials exist on the impact of implementing guidelines for the early detection of autism spectrum disorders (ASD). The aims of the present study were to develop and evaluate a clinically relevant integrated early detection programme based on the two-stage screening approach of Filipek et al. (1999), and to expand the evidence…

The utility of serum CA-125 in predicting extra-uterine disease in apparent early-stage endometrial cancer.

PubMed

Nicklin, James; Janda, Monika; Gebski, Val; Jobling, Thomas; Land, Russell; Manolitsas, Tom; McCartney, Anthony; Nascimento, Marcelo; Perrin, Lewis; Baker, Jannah F; Obermair, Andreas

2012-08-15

Surgical staging in early-stage uterine cancer is controversial. Preoperative serum CA-125 may be of clinical value in predicting the presence of extra-uterine disease in patients with apparent early-stage endometrial cancer. Between October 6, 2005, and June 17, 2010, 760 patients were enrolled in an international, multicentre, prospective randomized trial (LACE) comparing laparotomy with laparoscopy in the management of endometrial cancer apparently confined to the uterus. Of these, 657 patients with endometrial adenocarcinoma had a preoperative serum CA-125 value recorded. Multiple cross-validation analysis was undertaken to correlate preoperative serum CA-125 with stage of disease (Stage I vs. Stage II+) after surgery. Patients' median preoperative serum CA-125 was 14 U/ml. A cutoff point of 30 U/ml was associated with the smallest misclassification error, and using this cutoff, 98 patients (14.9%) had elevated CA-125 levels. Of those, 36 (36.7%) had evidence of extra-uterine disease. Of the 116 patients (17.7%) with evidence of extra-uterine disease, 31.0% had an elevated CA-125 level. On univariate and multivariable logistic regression analysis, only preoperative CA-125 level, but no other preoperative clinical characteristics were found to be associated with extra-uterine spread of disease. Utilizing a cutoff point of 30 U/ml achieved a sensitivity, specificity, positive predictive value and negative predictive value of 31.0, 88.5, 36.7 and 85.7%, respectively. Elevated CA-125 above 30 U/ml in patients with apparent early-stage disease is a risk factor for the presence of extra-uterine disease and may assist clinicians in the management of patients with clinical Stage I endometrial cancer. Copyright © 2011 UICC.