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Long-term Factors (long-term + factor)

Distribution by Scientific Domains

Earth and Environmental Science	50%

Selected Abstracts

Aspen succession and nitrogen loading: a case for epiphytic lichens as bioindicators in the Rocky Mountains, USA

JOURNAL OF VEGETATION SCIENCE, Issue 3 2009
Paul C. Rogers
Abstract Question: Can lichen communities be used to assess short- and long-term factors affecting seral quaking aspen (Populus tremuloides) communities at the landscape scale? Location: Bear River Range, within the Rocky Mountains, in northern Utah and southern Idaho, USA. Method: Forty-seven randomly selected mid-elevation aspen stands were sampled for lichens and stand conditions. Plots were characterized according to tree species cover, basal area, stand age, bole scarring, tree damage, and presence of lichen species. We also recorded ammonia emissions with passive sensors at 25 urban and agricultural sites throughout an adjacent populated valley upwind of the forest stands. Nonmetric multidimensional scaling (NMS) ordination was used to evaluate an array of 20 variables suspected to influence lichen communities. Results: In NMS, forest succession explained most variance in lichen composition and abundance, although atmospheric nitrogen from local agricultural and urban sources also significantly influenced the lichen communities. Abundance of nitrophilous lichen species decreased with distance from peak ammonia sources and the urban center in all aspen succession classes. One lichen, Phaeophyscia nigricans, was found to be an effective bioindicator of nitrogen loading. Conclusions: Lichen communities in this landscape assessment of aspen forests showed clear responses to long-term (stand succession) and short-term (nitrogen deposition) influences. At the same time, several environmental factors (e.g. tree damage and scarring, distance to valley, topography, and stand age) had little influence on these same lichen communities. We recommend further use of epiphytic lichens as bioindicators of dynamic forest conditions. [source]

National identity in Northern Ireland: stability or change?

NATIONS AND NATIONALISM, Issue 4 2007
JOHN COAKLEY
ABSTRACT. This article addresses a set of fundamental, long-term factors associated with the Northern Ireland conflict: the pattern of underlying values and attitudes, especially those related to identity, that have helped to shape the nature of intercommunal competition. Using all generally available public opinion data, the article explores in particular the nature of national identity and of related forms of belonging for political behaviour. It notes the mutually reinforcing character of political loyalties within the Protestant community (where national identity, communal affiliation, constitutional preference and party support tend to coincide in a ,Protestant-unionist' package) and the failure of this to be matched within the Catholic community (where the components of the ,Catholic-nationalist' package are less closely interrelated). It concludes by speculating about the implications of these value configurations for political development, suggesting that they are unlikely to contribute to any fundamental political change in Northern Ireland in the short or medium term. [source]

,What does it mean?' uncertainty, trust and communication following treatment for pre-cancerous cervical abnormalities

PSYCHO-ONCOLOGY, Issue 6 2007
Ilona Juraskova
Abstract The early detection of pre-cancerous cervical conditions has risen dramatically, prompting more in-depth investigations regarding psychological implications inherent within the diagnosis and treatment of this condition. This study aimed to identify factors that influence women's experience of diagnosis and treatment of cervical abnormalities and factors that facilitate positive adjustment. Using a semi-structured telephone interview, we interviewed 21 women (age 24,54) treated at a colposcopy clinic. Systematic recruitment of women with varying degrees of cervical abnormality (CIN 1,3) and time since treatment was undertaken to ensure representation of all relevant experiences and allow the identification of long-term factors. Coding of audio-taped, transcribed interviews and searching for themes was achieved by using NUD*IST software. The results identified uncertainty, trust and communication as the key factors for women following diagnosis and treatment. The primary concern following diagnosis was related to cancer but changed to a more prominent concern with future reproductive issues in the post-treatment period. The majority of women acknowledged the importance of the doctor's empathic communication style. These findings have important implications for future studies and clinical practice. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Impact of storms on mixed carbonate and siliciclastic shelves: insights from combined diffusive and fluid-flow transport stratigraphic forward model

BASIN RESEARCH, Issue 4 2004
A. Quiquerez
A quantitative stratigraphic model of mixed carbonate/siliciclastic continental shelves is presented to investigate the relationships between depositional processes and stratigraphic responses at long-term, large spatial scales. A diffusion model is combined with a fluid-flow approach to simulate both long-term factors, i.e. the processes controlling large-scale architecture, and short-term processes, i.e. sediment redistribution by storms. Any net sediment accumulation is the result of the succession of a storm and a fair-weather period. Sediments are mobilized by waves and advected by low-frequency currents during storm events. Sediments are then reworked and redistributed downslope by diffusive processes during fair-weather period. The results are successful in capturing several major characteristics of both modern and ancient depositional systems (geometry, differential preservation, net accumulation rates). The study highlights the importance of waves and unidirectional currents. Depositional geometry and shelf morphology depend on the balance between available sediment supply (generated in situ or detrital) and the transport energy, which is related to the style of sediment transport (diffusive or advective), and to the magnitude and frequency of storms. [source]