EVOLUTION, Issue 3 2003
Federico C. F. Calboli
Abstract Latitudinal genetic clines in body size occur in many ectotherms including Drosophila species. In the wing of D. melanogaster, these clines are generally based on latitudinal variation in cell number. In contrast, differences in wing area that evolve by thermal selection in the laboratory are in general based on cell size. To investigate possible reasons for the different cellular bases of these two types of evolutionary response, we compared the newly established North and South American wing size clines of Drosophila subobscura. The new clines are based on latitudinal variation in cell area in North America and cell number in South America. The ancestral European cline is also based on latitudinal variation in cell number. The difference in the cellular basis of wing size variation in the American clines, which are roughly the same age, together with the similar cellular basis of the new South American cline and the ancient European one, suggest that the antiquity of a cline does not explain its cellular basis. Furthermore, the results indicate that wing size as a whole, rather than its cellular basis, is under selection. The different cellular bases of different size clines are most likely explained either entirely by chance or by different patterns of genetic variance,or its expression,in founding populations. [source]

The relative sensitivity of four benthic invertebrates to metals in spiked-sediment exposures and application to contaminated field sediment

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2003
Danielle Milani
Abstract The relative sensitivity of four benthic invertebrates (Hyalella azteca, Chironomus riparius, Hexagenia spp., and Tubifex tubifex) was determined for Cd, Cu, and Ni in water-only and in spiked-sediment exposures. Survival (median lethal concentrations [LC50s] and the concentrations estimated to be lethal to 25% of test organisms [LC25s]), and endpoints for growth and reproduction (mean inhibitory concentrations [IC25s]) were compared. The sensitivities differed depending on the species and metal, although some trends emerged. In water-only exposures, H. azteca is the most sensitive species to cadmium and nickel, with mean LC50s of 0.013 and 3.6 mg/L, respectively; C. riparius is the most sensitive species to copper, with a mean LC50 of 0.043 mg/L. In the spiked-sediment exposures, the order in decreasing sensitivity to copper is Hyalella = Hexagenia < Chironomus < Tubifex for survival and growth/reproduction. For cadmium, the order in decreasing sensitivity is Hyalella = Chironomus < Hexagenia < Tubifex, and for nickel is Hyalella , Hexagenia < Chironomus < Tubifex. Chironomus riparius and Hexagenia spp. survival can be used to distinguish between toxicity caused by different metals. Species test responses in field-collected sediment (Collingwood Harbour, ON, Canada) were examined in an attempt to determine the causative agent of toxicity throughout, using the established species sensitivities. Sediment toxicity was categorized first by comparing species responses to those established for a reference database. Test responses in the field-collected sediment do not support causality by Cu, a suspected toxicant based on comparison of sediment chemistry with sediment quality guidelines. [source]

T-bet expression by dendritic cells is required for the repolarization of allergic airway inflammation,

EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 9 2008
Karin L. Heckman
Abstract By cross-linking B7-DC on dendritic cells (DC) the human IgM antibody (B7-DC XAb) shifts polarized immune responses from Th2 to Th1 in an antigen-specific manner. The molecular determinants governing the ability of DC to reprogram the polarity of T cell recall responses are not yet known. In addition to the expected role of T-bet expressed by T cells in regulating Th1 responses, we find using in vitro assays and an established in vivo model of allergic airway inflammation that T-bet expression by DC is also required for the polarity shift promoted by B7-DC XAb. T-bet expression by both T cells and DC is critically important for B7-DC XAb-induced down-regulation of IL-4, up-regulation of IFN-, and suppression of allergic airway inflammation. Moreover, retroviral reconstitution of T-bet expression in T-bet-deficient DC rescued their ability to modulate both naive and memory T-cell responses from Th2 to Th1. Our observations further our understanding of the critical mediators controlling the ability of DC to modify the responses of previously activated T cells and reveal the interesting use of the same transcription factor to regulate the inductive phenotype of DC and the inducible phenotype of T cells. [source]

A quantitative review comparing the yield of switchgrass in monocultures and mixtures in relation to climate and management factors

GCB BIOENERGY, Issue 1 2010
DAN WANG
Abstract Switchgrass (Panicum virgatum L.), a US Department of Energy model species, is widely considered for US biomass energy production. While previous studies have demonstrated the effect of climate and management factors on biomass yield and chemical characteristics of switchgrass monocultures, information is lacking on the yield of switchgrass grown in combination with other species for biomass energy. Therefore, the objective of this quantitative review is to compare the effect of climate and management factors on the yield of switchgrass monocultures, as well as on mixtures of switchgrass, and other species. We examined all peer-reviewed articles describing productivity of switchgrass and extracted dry matter yields, stand age, nitrogen fertilization (N), temperature (growing degree days), and precipitation/irrigation. Switchgrass yield was greater when grown in monocultures (10.9 t ha,1, n=324) than when grown in mixtures (4.4 t ha,1, n=85); yield in monocultures was also greater than the total yield of all species in the mixtures (6.9 t ha,1, n=90). The presence of legume species in mixtures increased switchgrass yield from 3.1 t ha,1 (n=65) to 8.9 t ha,1 (n=20). Total yield of switchgrass-dominated mixtures with legumes reached 9.9 t ha,1 (n=25), which was not significantly different from the monoculture yield. The results demonstrated the potential of switchgrass for use as a biomass energy crop in both monocultures and mixtures across a wide geographic range. Monocultures, but not mixtures, showed a significant positive response to N and precipitation. The response to N for monocultures was consistent for newly established (stand age <3 years) and mature stands (stand age ,3 years) and for lowland and upland ecotypes. In conclusion, these results suggest that fertilization with N will increase yield in monocultures, but not mixtures. For monocultures, N treatment need not be changed based on ecotype and stand age; and for mixtures, legumes should be included as an alternative N source. [source]

Molecular analyses and identification of promising candidate genes for loci on mouse chromosome 1 affecting alcohol physical dependence and associated withdrawal

GENES, BRAIN AND BEHAVIOR, Issue 5 2008
D. L. Denmark
We recently mapped quantitative trait loci (QTLs) with large effects on predisposition to physical dependence and associated withdrawal severity following chronic and acute alcohol exposure (Alcdp1/Alcw1) to a 1.1-Mb interval of mouse chromosome 1 syntenic with human chromosome 1q23.2-23.3. Here, we provide a detailed analysis of the genes within this interval and show that it contains 40 coding genes, 17 of which show validated genotype-dependent transcript expression and/or non-synonymous coding sequence variation that may underlie the influence of Alcdp1/Alcw1 on ethanol dependence and associated withdrawal. These high priority candidates are involved in diverse cellular functions including intracellular trafficking, oxidative homeostasis, mitochondrial respiration, and extracellular matrix dynamics, and indicate both established and novel aspects of the neurobiological response to ethanol. This work represents a substantial advancement toward identification of the gene(s) that underlies the phenotypic effects of Alcdp1/Alcw1. Additionally, a multitude of QTLs for a variety of complex traits, including diverse behavioral responses to ethanol, have been mapped in the vicinity of Alcdp1/Alcw1, and as many as four QTLs on human chromosome 1q have been implicated in human mapping studies for alcoholism and associated endophenotypes. Thus, our results will be primary to further efforts to identify genes involved in a wide variety of behavioral responses to alcohol and may directly facilitate progress in human alcoholism genetics. [source]

Lipid biomarker and carbon isotopic signatures for stromatolite-forming, microbial mat communities and Phormidium cultures from Yellowstone National Park

GEOBIOLOGY, Issue 1 2004
Linda L. Jahnke
ABSTRACT The molecular and isotopic compositions of lipid biomarkers from cultured filamentous cyanobacteria (Phormidium, also known as Leptolyngbya) have been used to investigate the community and trophic structure of photosynthetic mats from alkaline hot springs of the Lower Geyser Basin at Yellowstone National Park. We studied a shallow-water coniform mat from Octopus Spring (OS) and a submerged, tufted mat from Fountain Paint Pots (FPP) and found that 2-methylhopanepolyols and mid-chain branched methylalkanes were diagnostic for cyanobacteria, whereas abundant wax esters were representative of the green non-sulphur bacterial population. The biomarker composition of cultured Phormidium -isolates varied, but was generally representative of the bulk mat composition. The carbon isotopic fractionation for biomass relative to dissolved inorganic carbon (DIC; ,CO2) for cultures grown with 1% CO2 ranged from 21.4 to 26.1 and was attenuated by diffusion limitation associated with filament aggregation (i.e. cell clumping). Isotopic differences between biomass and lipid biomarkers, and between lipid classes, depended on the cyanobacterial strain, but was positively correlated with overall fractionation. Acetogenic lipids (alkanes and fatty acids) were generally more depleted than isoprenoids (phytol and hopanoids). The ,13CTOC for OS and FPP mats were somewhat heavier than for cultures (,16.9 and ,23.6, respectively), which presumably reflects the lower availability of DIC in the natural environment. The isotopic dispersions among cyanobacterial biomarkers, biomass and DIC reflected those established for culture experiments. The 7-methyl- and 7,11-dimethylheptadecanes were from 9 to 11 depleted relative to the bulk organic carbon, whereas 2-methylhopanols derived from the oxidation-reduction of bacteriohopanepolyol were enriched relative to branched alkanes by approximately 5,7. These isotopic relationships survived with depth and indicated that the relatively heavy isotopic composition of the OS mat resulted from diffusion limitation. This study supports the suggestion that culture studies can establish valid isotopic relationships for interpretation of trophic structure in modern and ancient microbial ecosystems. [source]

The Amenity Complex: Towards a Framework for Analysing and Predicting the Emergence of a Multifunctional Countryside in Australia

GEOGRAPHICAL RESEARCH, Issue 3 2007
NEIL ARGENT
Abstract There is growing consensus among academics, regional development organisations and rural communities that the future growth and development of rural regions is increasingly dependent upon their ability to convey, to both established and prospective residents, the ,amenity' of their local physical, social and economic environments. However, little research to date has sought to identify exactly what comprises ,amenity' in the rural context, or has examined how this conceptually slippery quality is distributed across rural Australia, or how it influences local demographic, socio-economic and land use change. This paper attempts a broad scale investigation of rural amenity in the south-east Australian ecumene, identifying its core components in this context, mapping its distribution and assessing the nature of its influence over in-migration rates over the past three decades. The paper finds that, at a macro-scale, amenity tends to follow a general gradient from high to low according to distance from the coast, and that its relationship with in-migration rates has increased substantially between 1976,1981 and 1996,2001. [source]

Development Section, April 2008

GEOGRAPHY COMPASS (ELECTRONIC), Issue 3 2008
Cheryl McEwan
EDITORIAL It is a great privilege to serve as Editor for the Development section of Geography Compass. The journal is an exciting new venture in electronic publishing that aims to publish state-of-the-art peer-reviewed surveys of key contemporary issues in geographical scholarship. As the first Editor of this section, it is my responsibility to establish the key aims and innovations for this section of the journal. These include: publishing reviews of scholarship on topics of contemporary relevance that are accessible and useful to researchers, teachers, students and practitioners; developing the range of topics covered across the spectrum of development geography; helping to set agendas in development geography by identifying gaps in existing empirical and conceptual research; commissioning articles from both established and graduate/early career researchers who are working at the frontiers of development geography; and communicating the distinctiveness of Geography Compass. Part of this distinctiveness is in publishing articles that are both of scholarly excellence and accessible to a wide audience. The first volume of Geography Compass was published in 2007, covering a wide range of topics (e.g. migration, children, technology, grassroots women's organizations, civil society, biodiversity, tourism, inequality, agrarian change, participatory development, disability, spirituality) in a number of specific geographical areas (e.g. Africa/southern Africa, Caribbean, China, Peru). Forthcoming in 2008/2009 are articles on the Gambia, Latin America, the Philippines, Southeast Asia, Bangladesh and South Africa, focusing on topics such as food security, comparative post-socialism, foreign aid and fair trade. Building on these diverse and excellent articles, I plan to communicate the distinctiveness of Development in a number of ways. First, I encourage an ecumenical approach to the notion of ,development geography' and welcome contributions from scholars across a range of social science disciplines whose work would be useful to a geography audience. This is important, not least because both development and geography, in disciplinary terms, are largely European inventions. Many scholars in Latin America, Africa and Asia, for example, do not refer to themselves as either development specialists or geographers but are producing important research in areas of direct relevance to students and researchers of ,development geography'. As the first editions illustrate, I also seek to publish articles that reflect ,development' in its broadest sense, encompassing economic, (geo)political, social, cultural and environmental issues. 2008 will be an interesting year for development, with a number of important issues and events shaping discourse and policy. These include: the Beijing Olympics and increasing focus on China's role in international development; political change in a number of African countries (Kenya, Zimbabwe, South Africa); the US presidential elections and potential shifts in policy on climate change, trade and security; the impacts of the Bali roadmap on climate change in the current economic context; the increasing number of impoverished people in Asia (notably China and India), sub-Saharan Africa and Latin America (notably Brazil) that even the World Bank has acknowledged; the implications of the increasing role of philanthropic foundations (e.g. the Gates Foundation and those emerging in India and Russia) in international development. I hope to see some of these issues covered in this journal. Second, I am keen to break down the association between ,development' and parts of the world variously categorized as ,Third World', ,Global South' or ,Developing World' by publishing articles that cut across North and South, East and West. The intellectual and disciplinary practices within (Western) geography that separate those researching issues in the South and post-socialist contexts from those researching similar issues in advanced capitalist economies are, it seems, no longer sustainable or sensible. Moreover, while studies of transnational and ethical trade, neoliberalism, household economies and ,commodity chains', for example, incorporate a multitude of case studies from across the world, these tend to be understood through conceptual lenses that almost always have their theoretical antecedents in Western theorization. The notion of ,learning from' debates, policy and practice in other parts of the world is still relatively alien within the discipline. There are thus issues in how we research and teach ethically and responsibly in and about different parts of the world, and in which this journal might make a contribution. Third, and related, part of my responsibility is to ensure that Compass reflects the breadth of debate about ,development' by publishing articles written by a truly international range of scholars. This has proved to be a challenge to date, in part reflecting the newness of the journal and the difficulties posed by English language publication. However, an immediate aim is to publish the work and ideas of scholars based outside of Anglophone contexts, in the Global South and in post-socialist contexts, and to use international referees who are able to provide valuable commentaries on the articles. A longer-term aim is to also further internationalize the Editorial Board. Currently, one-third of the Editorial Board is non-UK and I plan to increase this to at least 50% in future. Fourth, I plan to ensure that the Development section takes full advantage of electronic publication and the opportunities this offers. Thus, while I am keen to retain a word limit in the interest of publishing accessible articles, the lack of constraint regarding page space enables authors to include a wide range of illustrative and other material that is impossible in print journals. I plan to encourage authors to make greater use of visual materials (maps, photographs/photo-essays, video, sound recordings, model simulations and datasets) alongside text as well as more innovative forms of presentation where this might be appropriate. Finally, in the coming year, I intend to work more closely with other Compass section Editors to realize the potential for fostering debate that cuts across subdisciplinary and even disciplinary boundaries. The journal publishes across the full spectrum of the discipline and there is thus scope for publishing articles and/or special issues on development-related topics that might best be approached through dialogue between the natural and social sciences. Such topics might include resources (e.g. water, oil, bio-fuels), hazard and risk (from environmental issues to human and state security), and sustainability and quality of life (planned for 2008). Part of the distinctiveness of Compass is that electronic-only publication ensures that articles are published in relatively quick time , in some cases less than 3 months from initial submission to publication. It thus provides an important outlet for researchers working in fast-changing contexts and for those, such as graduate and early-career researchers, who might require swift publication for career purposes. Of course, as Editor I am reliant on referees both engaging with Manuscript Central and providing reports on articles in a relatively short space of time to fully expedite the process. My experience so far has been generally very positive and I would like to thank the referees for working within the spirit of the journal. Editing a journal is, of course, a collaborative and shared endeavour. The Development Editorial Board has been central to the successful launch of Development by working so generously to highlight topics and potential authors and to review articles; I would like to take this opportunity to thank Tony Bebbington, Reg Cline-Cole, Sara Kindon, Claire Mercer, Giles Mohan, Warwick Murray, Richa Nagar, Rob Potter, Saraswati Raju, Jonathan Rigg, Jenny Robinson and Alison Stenning. The Editors-in-Chief , Mike Bradshaw and Basil Gomez , have provided invaluable advice while adding humour (and colour) to the editorial process. Colleagues at Wiley-Blackwell have provided superb support, in particular, Helen Ashton who is constantly on hand to provide advice and assistance. I look forward to working closely with these people again in the coming year, as well as with the authors and readers who are vital to ensuring that Geography Compass fulfils its remit. [source]

The effect of sward structure as influenced by ryegrass genotype on bite dimensions and short-term intake rate by dairy cows

GRASS & FORAGE SCIENCE, Issue 1 2003
P. D. Barrett
Abstract The effects of genotypic variation in ryegrasses on sward structure, bite dimensions and intake rate by dairy cows were investigated. Two experiments were conducted. In Experiment 1, swards were in a vegetative state whereas, in Experiment 2, they were partly reproductive and were taller with higher herbage mass but lower leaf proportion than in Experiment 1. Applicability of relationships between sward structure and bite characteristics, previously established from artificial or hand-constructed swards, to field conditions were tested. Additional short-term intake rates and/or sward structural characteristics were considered as indicators of potential intake for use in protocols for the evaluation of grass varieties. Four cultivars were studied: AberElan, Twins (diploid and tetraploid perennial ryegrasses respectively), Polly, a hybrid ryegrass (perennial × Italian ryegrass) and Multimo (Italian ryegrass), each established in 200-m2 plots in four replicated blocks. Herbage intake rate was determined by short-term liveweight change (taking account of insensible weight loss) using 16 dairy cows allocated to four balanced groups with each plot grazed by one group for a 1-h assessment period. One block was grazed per day, over a 4-d experimental period, with each group grazing each variety in a complete crossover design. Sward characteristics and bite rate were also measured in both experiments. Bite dimensions were subsequently estimated, with bite depth being determined as a function of extended tiller height (ETH) in both experiments. Within both experiments, bite mass and intake rate did not differ significantly between swards of different cultivars despite swards containing Multimo generally having a higher ETH and water-soluble carbohydrate concentration and lower green leaf mass, sward bulk density and neutral-detergent fibre concentration than the other swards. However, bite depth was significantly higher (P < 0·01) in swards containing Multimo swards than in the others and, in Experiment 1, bite depth, as a proportion of ETH, was higher in swards containing Multimo and lower in those containing Twins than in the other two cultivars, whereas there was no difference in Experiment 2. Taking both experiments together, the mean bite depth was 0·5 of ETH with sward bulk density accounting for almost half the variance in the relationship between bite depth and ETH. The bulk density of the bite (bite mass per unit bite volume), measured in Experiment 2, followed a similar pattern to sward bulk density, increasing in the order Multimo, Polly, AberElan and Twins. It is concluded that the relationships between sward characteristics and bite dimensions, derived from artificial swards, are applicable to field swards, although the range in natural ryegrass sward characteristics is usually not as wide as in experiments using artificial swards. Lack of precision in the measurement of short-term intake and in sward-based measurements is likely to preclude their use in the evaluation of grass varieties. [source]

Craniofacial resection for tumors of the nasal cavity and paranasal sinuses: A 25-year experience

HEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 10 2006
David J. Howard FRCS, FRCS(Ed)
Abstract Background. Craniofacial resection is the established "gold standard" for surgical treatment of tumors affecting the anterior skull base. Methods. This study analyzed 308 patients (220 males, 88 females) who had undergone craniofacial resection for sinonasal neoplasia with up to 25-year follow-up. Results. An overall actuarial survival of 65% at 5 years and 47% at 10 years was found for the cohort as a whole. For patients with malignant tumors, the 5-year actuarial survival was 59%, falling to 40% at 10 years. For patients with benign pathology, the actuarial survival was 92% at 5 years falling to 82% at 10 years. Statistical analysis again identified brain involvement, type of malignancy, and orbital involvement as the 3 most significant prognostic factors. Conclusion. Analysis of one of the largest single institution cohorts over a 25-year period provides a baseline against which other approaches such as an entirely endoscopic skull base resection must be judged. © 2006 Wiley Periodicals, Inc. Head Neck, 2006 [source]

Studies of murine schistosomiasis reveal interleukin-13 blockade as a treatment for established and progressive liver fibrosis

HEPATOLOGY, Issue 2 2001
Monica G. Chiaramonte
In several allergic, autoimmune, and infectious diseases, fibrosis is a major cause of morbidity and mortality. Here, using a model of infection-induced liver fibrosis, we show that interleukin (IL)-13 is required at all stages of Schistosomiasis mansoni infection to induce fibrosis. IL-4 production was preserved in IL-13,deficient mice, yet failed to significantly contribute to the fibrotic response in either acute or chronic infection. Significant fibrosis develops in all infected mice, although the magnitude of the response varies widely in inbred mice. C3H/HeN, BALB/c, and C57BL/6 mice develop high, intermediate, and low levels of fibrosis, respectively. Despite these differences, IL-13 antagonism resulted in a marked amelioration of fibrosis in all strains. The fibrotic mechanism in the high- and low-responder strains was unrelated to their tissue eosinophil or mast cell responses, but did correlate with their patterns of IL-13, IL-10, and interferon gamma (IFN-,) mRNA expression. Indeed, severe fibrosis correlated with a high IL-13 and low IFN-,/IL-10 mRNA response. Because fibrotic diseases are typically progressive disorders, an important issue was to determine whether IL-13 inactivation might be used to treat an established and ongoing fibrotic disease. Here, IL-13 antagonism was highly efficacious, even after fibrosis and the Th2 cytokine response were firmly established. These studies demonstrate the central role played by IL-13 in fibrogenesis and suggest that therapeutic approaches aimed at disrupting the IL-13 pathway will be highly effective at preventing fibrotic disease caused by chronic Th2-mediated inflammatory reactions. [source]

Human reliability: A key to improved quality in manufacturing

HUMAN FACTORS AND ERGONOMICS IN MANUFACTURING & SERVICE INDUSTRIES, Issue 4 2005
Heiner Bubb
For one to learn, one must make mistakes. Human error can be defined on the basis of the definition of quality. Because quality is influenced by human actions, the so-called performance shaping factors have an important influence on the human error probability. Different methods have been developed to predict human error probability. One of the most established and detailed methods is THERP (technique for human error rate prediction), which was originally developed for application in the nuclear power industry. Here this method is applied to a simple example of manufacturing. Further experimental research in the area of commission will be reported, where methods of error prediction were also applied. In both cases, measures of improving human reliability can be derived. © 2005 Wiley Periodicals, Inc. Hum Factors Man 15: 353,368, 2005. [source]

Developing clinical leaders in Australian aged care homes

INTERNATIONAL JOURNAL OF EVIDENCE BASED HEALTHCARE, Issue 1 2006
Alan Pearson RN PhD FRCNA FAAG FRCN
Abstract The role of clinical leadership in implementing evidence based practice is increasingly recognised in the health and social care fields. This paper briefly reviews the literature on clinical leadership and evidence-based practice in aged care and describes the established of an aged care clinical fellowship program in Australia. The purpose of this paper is to introduce the reports of four aged care clinical fellows reported elsewhere in this issue of the International Journal of Evidence-Based Healthcare. [source]

Immigrant Gateways and Hispanic Migration to New Destinations,

INTERNATIONAL MIGRATION REVIEW, Issue 3 2009
Daniel T. Lichter
Our understanding of the underlying demographic components of population change in new Hispanic destinations is limited. In this paper, we (1) compare Hispanic migration patterns in traditional settlement areas with new growth in emerging Hispanic destinations; (2) examine the role of immigration vis-à-vis domestic migration in spurring Hispanic population redistribution; and (3) document patterns of migrant selectivity, distinguishing between in-migrants and non-migrant Hispanics at both the origin and destination. We use several recent datasets, including the 1990 and 2000 Public Use Microdata Samples (which include new regional geocodes), and the 2005 and 2006 files of the American Community Survey. Our results document the widespread dispersion of the Hispanic population over the 1990,2006 period from established Hispanic gateways into new Hispanic areas and other parts of the country. Nearly one-half of Hispanic net migration in new destinations comes from domestic gains. In contrast, both established and other Hispanic areas depend entirely on immigration, with each losing domestic migrants to high growth areas. Migrant flows also are highly differentiated by education, citizenship, and nativity. To fully understand the spatial diffusion of Hispanics requires a new appreciation of the complex interplay among immigration, internal domestic migration, and fertility. [source]

Disturbance facilitates rapid range expansion of aspen into higher elevations of the Rocky Mountains under a warming climate

JOURNAL OF BIOGEOGRAPHY, Issue 1 2010
Simon M. Landhäusser
Abstract Aim, Trembling aspen (Populus tremuloides Michx.) is absent in the upper foothills region of west-central Alberta because of the cold conditions and short growing season at this high elevation. However, in recent years it appears that aspen has been establishing from seed in this zone and that it has been doing so mainly as a result of forest harvesting. The objectives of this study were to determine the frequency of and types of microsite required for the successful establishment of aspen seedlings at these higher elevations. Location, Rocky Mountains Upper Foothills Natural Subregion of west-central Alberta, Canada. Methods, The current distribution of mature aspen and the presence and absence of aspen seedlings in harvested areas were determined in an area c. 300 km2 in size, using ground and aerial surveys. In an intensive study, 12 belt transects (180 m long and 5 m wide) were established in areas disturbed by forest harvesting at high elevations where no aspen was present prior to harvesting. Transects were surveyed seven growing seasons after disturbance and the microsites occupied by aspen seedlings were characterized according to their substrate and microtopography. Similarly, the availability of different substrates and microtopographic positions were assessed by systematic point sampling on these sites. Results, On level surfaces, aspen seedling regeneration was found up to 200 m higher in elevation than the mature aspen in the original undisturbed forests. Overall, there were 428 seedlings ha,1 established on these transects, and the age distribution indicates that aspen seedlings had established in each of the seven growing seasons since the disturbance. Nearly all of the seedlings (93%) were established on mineral soil microsites and virtually no seedlings were established on undisturbed forest floor layers. Significantly more seedlings were found in concave microtopographic positions. Main conclusions, This study indicates that aspen establishment from seed is currently not a stochastic event and demonstrates that aspen is rapidly expanding its range upslope in the Canadian Rocky Mountain region as a result of forest management practices that expose mineral soil substrates in conjunction with a warming climate. The change in canopy composition from conifer to deciduous forests at these higher elevations will have far-reaching implications for ecosystem processes and functions. [source]

What youngsters say about adults: seedling roots reflect clonal traits of adult plants

JOURNAL OF ECOLOGY, Issue 3 2007
MARIE, MILAUEROVÁ
Summary 1Grime's theory on plant strategies predicts that the set of traits present in established plants is not correlated with that found in the regenerative stage of the life cycle. We tested this prediction and further investigated whether clonal growth traits, which are found in adult plants but also affect regeneration, are correlated with seedling traits. 2We characterized seedling root systems by their total length, number of root tips and several architectural parameters (length of exterior and interior root links and two topological indices). These below-ground traits were supplemented by the ratio of leaf area to root length, representing relative investment into photosynthesizing surface. We compared seedling traits with clonal growth traits, adult plant heights, and species positions on gradients of nitrogen and water availability. 3Plant species with limited horizontal spread by clonal growth exhibited a larger relative investment in photosynthetic area and also developed larger root systems as seedlings. 4Seedlings of species with taller shoots and those which occur naturally at nutrient-rich sites developed both larger roots and more dichotomously branched root systems (with higher total length and more branches). 5Taking phylogenetic inertia into account showed that this explained large parts of the variation in seedling traits. Relationships between clonal spread and seedling traits were strengthened by phylogenetic correction. 6Our study shows that some of the traits of clonal growth affect both the established and the regenerative stages of the life cycle, suggesting that an evolutionary trade-off exists between the ability to spread clonally and performance at the seedling stage. Species not able to escape from less favourable conditions by extensive clonal spread seem to be more able to exploit the location in which they germinate. [source]

Forest canopy and community dynamics in a temperate old-growth evergreen broad-leaved forest, south-western Japan: a 7-year study of a 4-ha plot

JOURNAL OF ECOLOGY, Issue 5 2001
Masahiro Miura
Summary 1Forest canopy gap and community dynamics were studied in a 4-ha permanent plot of an old-growth evergreen broad-leaved forest dominated by Castanopsis cuspidata var. sieboldii and Distylium racemosum in the Tatera Forest Reserve, Tsushima Islands, south-western Japan. The forest was affected by a powerful typhoon in 1987 and was monitored from 1990 to 1997. 2In 1990, all woody stems , 5 cm diameter at breast height (d.b.h.) in the plot were identified, mapped and marked, and the state of 1600 5 m × 5 m contiguous quadrats used to locate canopy gaps. Gaps occupied 17.1% of the plot, which contained 4494 tree and shrub stems (total basal area 63.48 m2 ha,1). Gaps were re-censused in 1997 and both marked and newly recruited (, 5 cm d.b.h.) stems were recorded in 1992 and 1997. 3Over 7 years the rates of canopy gap formation and closure were 0.72% year,1 and 1.61% year,1, respectively, mortality and recruitment rates were 0.97% year,1 and 0.99% year,1, and the rates of loss and gain in basal area were 0.95% year,1 and 0.83% year,1. 4The mortality of stems was size-dependent, with those in middle size classes having the lowest rates. Mortality of stems was lower in canopy and higher in the understorey, while the proportion of stems killed by disturbances increased with height. 5Stems that died during the 7 years were predominantly located in newly created gaps, whereas stems were recruited into both established and new gaps. Deciduous broad-leaved species were largely restricted to gaps that remained open throughout the study. 6Both composition and structure of the forest changed in response to disturbance-related effects on canopy dynamics. [source]

Tobacco use, cancer causation and public health impact

JOURNAL OF INTERNAL MEDICINE, Issue 6 2002
H. Kuper
Abstract.,Kuper H, Adami H-O, Boffetta P (University College London, Torrington Place, London, UK; Karolinska Institutet, Stockholm, Sweden; and International Agency for Research on Cancer, Lyon, France). Tobacco use, cancer causation and public health impact. J Intern Med 2002; 251: 455,466. This review describes global patterns of tobacco use and the mechanisms by which tobacco use is involved in carcinogenesis. A second part will discuss the association between tobacco use and risk of specific cancer types. To bacco use has traditionally been a practice of high-income countries, but it has recently been taken up in low-income countries and it is particularly common in men. A wide variety of tobacco products exist, of which cigarettes are most frequently consumed. Tobacco products contain more than 50 established or identified carcinogens and these may increase risk of cancer by causing mutations that disrupt cell cycle regulation, or through their effect on the immune or endocrine systems. Certain factors such as genes, diet and environmental exposures may alter susceptibility to cancer in tobacco users. Today at least 15% of all cancers are estimated to be attributable to smoking, but this figure is expected to increase because of the uptake of tobacco use in low-income countries. [source]

Interaction of cysteine with Cu2+ and group IIb (Zn2+, Cd2+, Hg2+) metal cations: a theoretical study

JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 3 2005
M. Belcastro
Abstract The structure and energetics of complexes obtained upon interaction between cysteine and Zn2+, Cd2+, Hg2+ and Cu2+ cations were studied using quantum chemical density functional theory calculations with the 6,311++G** orbital basis set and relativistic pseudopotentials for the cations. Different coordination sites for metal ions on several cysteine conformers were considered. In their lowest energy complexes with the amino acid, the Zn2+ and Cd2+ cations appear to be three-coordinated to carbonyl oxygen, nitrogen and sulfur atoms, whereas the Cu2+ and Hg2+ ions are coordinated to both the carbonyl oxygen and sulfur atoms of one of the zwitterion forms of the amino acid. Bonds of metal cations with the coordination sites are mainly ionic except those established with sulfur, which show a small covalent character that become most significant when Cu2+ and Hg2+ are involved. The order of metal ion affinity proposed is Cu > Zn > Hg > Cd. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Embryonic inner ear cells use migratory mechanisms to establish cell patterns in vitro

JOURNAL OF NEUROSCIENCE RESEARCH, Issue 2 2006
Lynne M. Bianchi
Abstract The hair cells of the sensory epithelium in the inner ear are among the most precisely organized cells in vertebrates. The mechanisms that lead to this orderly arrangement are only beginning to be understood. It has been suggested that hair cells use migratory mechanisms to help achieve their final position in the organ of Corti. The small size and complex organization of the intact inner ear have made it difficult to monitor changes in hair cell location over time in vivo. In the present study, an established in vitro assay of dissociated, embryonic inner ear cells was used to monitor how hair cells reorganize over time. The hair cell specific marker myosin-VI demonstrated that hair cell precursors from both cochlear and vestibular regions reorganized into specific patterns between 3,24 hr in vitro. In contrast to the unlabeled cells, the myosin-VI-positive cells extended processes while establishing the hair cell patterning within an aggregate. These studies support the hypothesis that hair cell precursors actively migrate to help achieve final patterning within the inner ear sensory epithelium. © 2005 Wiley-Liss, Inc. [source]

Endothelin-1 modulates anterograde fast axonal transport in the central nervous system

JOURNAL OF NEUROSCIENCE RESEARCH, Issue 5 2005
Martha E. Stokely
Abstract Anterograde fast axonal transport (FAxT) maintains synaptic function and provides materials necessary for neuronal survival. Localized changes in FAxT are associated with a variety of central nervous system (CNS) neuropathies, where they may contribute to inappropriate remodeling, a process more appropriately involved in synaptic plasticity and development. In some cases, developmental remodeling is regulated by localized secretion of endothelins (ETs), neuroinflammatory peptides that are also pathologically elevated in cases of neurologic disease, CNS injury, or ischemia. To investigate the potential role of ETs in these processes, we decided to test whether locally elevated endothelin-1 (ET-1) modulates FAxT in adult CNS tissues. We used the established in vivo rat optic nerve model and a novel ex vivo rat hippocampal slice model to test this hypothesis. In vivo, exogenously elevated vitreal ET-1 significantly affected protein composition of FAxT-cargos as well as the abundance and peak delivery times for metabolically-labeled proteins that were transported into the optic nerve. Proteins with molecular weights of 139, 118, 89, 80, 64, 59, 51, 45, 42, 37, and 25 kDa were evaluated at injection-sacrifice intervals (ISIs) of 24, 28, 32, and 36 hr. In acute hippocampal slices maintained on nonvascular supplies of glucose and oxygen, ET-1 significantly decreased the distance traveled along the Schaffer collateral tract by nonmetabolically-labeled lipid rafts at 5 and 10 min after pulse-labeling. In both models, ET-1 significantly affected transport or targeted delivery of FaxT-cargos, suggesting that ET-1 has the potential to modulate FAxT in adult CNS tissues. © 2005 Wiley-Liss, Inc. [source]

The differential effects of the radioprotectant drugs amifostine and sodium selenite treatment in combination with radiation therapy on constituent bone cells, ewing's sarcoma of bone tumor cells, and rhabdomyosarcoma tumor cells in vitro

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 11 2008
Bryan S. Margulies
Abstract The purpose of this study was to determine the differential effects of therapeutic X-radiation on constituent bone cells relative to the pediatric tumor cells: Ewing's sarcoma of bone and rhabdomyosarcoma. In addition, the radioprotectant drugs amifostine and sodium selenite were administered to constituent bone cells and the two tumor cells to determine if the radioprotectants differentially protect bone cells while not benefiting the tumor cells. These studies are a necessary first step in determining the potential clinical benefit of radioprotective therapy. An established in vitro cell culture model employing both constituent bone cells (osteoblasts, primary bone marrow monocytes, osteoclasts chondrocytes, and endothelial cells) and the tumor cells lines (Ewing's sarcoma of bone and rhabdomyosarcoma) were exposed to irradiation, amifostine, and sodium selenite. Cells were then assayed for changes in cell number, cytotoxicity, mineralization, bone resorption, cell attachment, osteocalcin, caspase-3 expression, clonogenic survival, and alkaline phosphatase expression. Radiation therapy differentially decreased cell number; with osteoblasts being shown to be the least sensitive to irradiation, the tumor cells had an intermediate sensitivity and monocytes were the most sensitive. Both amifostine and sodium selenite protected chondrocytes and osteoblasts from the negative effects of irradiation, while not protecting the tumor cells. The pediatric tumor cell lines were generally more radiosensitive than the bone cells examined. The radioprotectant drugs amifostine and sodium selenite provided significant radioprotection to constituent bone cells while not protecting the tumor cells. Finally, amifostine and sodium selenite therapy provided an additional benefit beyond radioprotection by increasing cytotoxicity in nonirradiated and irradiated tumor cells. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1512,1519, 2008 [source]

Solid phase peptide synthesis on epoxy-bearing methacrylate monoliths

JOURNAL OF PEPTIDE SCIENCE, Issue 12 2004
E. Vlakh
Abstract Monoliths based on a copolymer of glycidyl methacrylate (GMA) and ethylene dimethacrylate (EDMA) can be used directly as sorbents for affinity chromatography after solid phase peptide synthesis. The quality of the synthesized products, the amount of grown peptides on a support and the reproducibility of the process must be considered. A determination of the quantity of the introducing ,-Ala (and, consequently, the total amount of synthesized peptide) was carried out. Three peptides complementary to recombinant tissue plasminogen activator (t-PA) have been synthesized using Fmoc-chemistry on GMA-EDMA disks. The peptidyl ligands were analysed by amino acid analysis, ES-MS and HPLC methods. The affinity binding parameters were obtained from frontal elution data. The results were compared with those established for GMA-EDMA affinity sorbents formed by the immobilization of the same but separately synthesized and purified ligands. The immobilization on GMA-EDMA disks was realized using a one-step reaction between the amino groups of the synthetic ligand and the original epoxy groups of monolithic material. The affinity constants found for two kinds of sorbent did not vary significantly. Finally, the directly obtained affinity sorbents were tested for t-PA separation from a cellular supernatant. Copyright © 2004 European Peptide Society and John Wiley & Sons, Ltd. [source]

Basic Personality Dispositions, Self-Esteem, and Personal Goals: An Approach-Avoidance Analysis

JOURNAL OF PERSONALITY, Issue 5 2006
Sara A. Heimpel
ABSTRACT This research examined the hypothesis that self-esteem negatively predicts avoidance (relative to approach) personal goals, as well as the hypothesis that self-esteem mediates the link between indicators of approach and avoidance temperament and avoidance (relative to approach) personal goals. Study 1 established that self-esteem is indeed negatively related to avoidance (relative to approach) goals, even with social desirability concerns controlled. In Study 2, self-esteem was found to mediate the relation between Neuroticism (conceptualized as an indicator of avoidance temperament) and avoidance (relative to approach) personal goals. In Study 3, self-esteem was documented as a mediator of the relation between BAS and BIS sensitivity (conceptualized as indicators of approach and avoidance temperament, respectively) and avoidance (relative to approach) personal goals in the achievement domain. The implications of these findings for our understanding of basic personality dispositions, self-esteem, and personal goals are discussed. [source]

Effects of continuous exposure to digoxin on MDR1 function and expression in Caco-2 cells

JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 5 2003
Kohji Takara
The Caco-2 cell line has been used widely for studying intestinal permeability and several transport functions, and express the multidrug resistance transporter MDR1/P-glycoprotein. Previously, the transient exposure to digoxin for 24h was found to induce MDR1 mRNA in Caco-2 cells. Here, a digoxin-tolerant Caco-2 subline (Caco/DX) was newly established by the continuous exposure of Caco-2 cells to digoxin, and the effects of continuous exposure to digoxin on MDR1 were examined. The 50% growth inhibitory concentration (IC50) values for digoxin in Caco-2 and Caco/DX cells were 17.2 and 81.4 nm, respectively. The IC50 values for paclitaxel, an MDR1 substrate, were 1.0 and 547 nm, respectively, whereas the cytotoxicity of 5-fluorouracil was comparable in both cells. The uptake and efflux of Rhodamine123, an MDR1 substrate, in Caco/DX cells were significantly less and greater, respectively, than those in Caco-2 cells, and these transports were affected by the addition of ciclosporin. The expression of MDR1 mRNA in Caco/DX cells was approximately 2- and 1.7-fold compared with Caco-2 cells and Caco-2 cells treated with 100 nm digoxin for 24 h, respectively. On the other hand, MRP1 mRNA in Caco/DX cells was unchanged. These observations confirmed that the continuous exposure to digoxin, as well as the transient exposure, induced MDR1 in Caco-2 cells. [source]

Developing services for the carers of young adults with early-onset psychosis , listening to their experiences and needs

JOURNAL OF PSYCHIATRIC & MENTAL HEALTH NURSING, Issue 5 2005
J. SIN msc bsc (hons)-thorn bn bgs rmn
The care-giving experience of carers of young adults with early onset psychosis is relatively unexplored. New carers are less likely to be engaged with local services for carers and families, than those more established in their caring role. Understanding the experience of these carers provides some valuable insight into the value of caring and in guiding service development. This paper reports on a study designed to explore carers' experiences of caring for a young adult diagnosed with a first psychotic episode and their needs in relation to the development of an early intervention for psychosis service. A phenomenological approach was used. Eleven carers were given a semi-structured interview in their own homes. All of the carers in the study had a son with early onset psychosis. The outcome revealed that all carers were providing a comprehensive range of practical, emotional and financial support for their son including initiating and sustaining engagement between them and local mental health services. Many carers were felt to be invisible and silent partners in care and felt under-valued by mental health services. [source]

Dynamics of hepatitis C virus quasispecies turnover during interferon- , treatment

JOURNAL OF VIRAL HEPATITIS, Issue 6 2003
M. von Wagner
Summary. Interferon- , (IFN) has been shown to accelerate the evolution of hepatitis C virus (HCV) variants (quasispecies) in nonresponder patients. Different sensitivities of HCV variants to IFN are discussed as a possible mechanism. In the present study, quasispecies were investigated in detail by a newly established and validated direct solid-phase sequencing of the hypervariable region 1 (HVR1), during the initial 3 months of IFN therapy. According to single strand conformation polymorphism (SSCP) analysis, 14 of 26 (54%) virologic nonresponders with quasispecies evolution were identified. Six representative patients with SSCP changes were selected for frequent HVR1 sequencing. Pre-existing variants were identified by cloning and sequencing of the pretreatment serum HCV sample. In one patient the major type was substituted by a minor variant within 3 days of treatment while in the majority of patients the pretreatment major type did not decline before days 26,57 of treatment. Total serum HCV RNA levels remained constant in all patients. In conclusion, although quasispecies evolution during IFN therapy is common, it occurs after a wide range of time intervals after initiation of therapy. Thus, nonresponse to IFN cannot exclusively be explained by changes in the quasispecies. [source]

Measurement of protection afforded by ultraviolet-absorbing window film using an in vitro model of photodamage

LASERS IN SURGERY AND MEDICINE, Issue 4 2006
Eric F. Bernstein MD
Abstract Background and Objectives The effects of chronic sun damage including telangiectasias, solar lentigos, rhytides, enlarged pores, sagging skin, and pre-cancerous and cancerous growths are among the most common presenting complaints in a dermatologist's office. These changes are often worse on the driver's side of the face, emphasizing the role of UVA exposure received while driving in producing these changes. This study was undertaken to measure the ability of car window glass alone and in combination with ultraviolet (UV)-absorbing film to reduce UV-damage as measured using an established in vitro model of photoprotection. Study Design Materials and Methods Using the 3T3 neutral red uptake photoprotection assay with solar simulating radiation (SSR) administered by a xenon arc solar simulator, we measured the photoprotection ability of auto glass, window film that filters UV radiation, and the combination of window film and auto glass. Results As measured by the 3T3 neutral red uptake photoprotection assay, auto glass reduced cell death from SSR by 29%, while window film reduced it 90%, and the combination of auto glass and film reduced cell death by 93%, when compared to unfiltered SSR. Conclusions Window film that filters UV radiation results in dramatic reductions in cytotoxicity when measured by the neutral red uptake photoprotection assay. Widespread use of window film provides an ever-present barrier to ultraviolet A (UVA) exposure and could potentially reduce the detrimental effects of UVA, including photoaging, skin cancer, and ocular damage, such as cataracts. In addition, such film is essential for patients suffering from conditions sensitive to UV radiation, such as lupus erythematosis. Lasers Surg. Med. 38:337,342, 2006. © 2006 Wiley-Liss, Inc. [source]

Dose-response relationship of rocuronium: A comparison of electromyographic vs. acceleromyographic-derived values

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 3 2005
A. F. Kopman
Background: Acceleromyography (AMG) is being employed with increasing frequency as a research tool. However, there is almost no information available regarding the accuracy of values for drug potency obtained using AMG. This study was an attempt to determine if AMG-derived ED50/95 values are interchangeable with those measured with a more traditional neuromuscular monitor. Methods: Thirty adult patients were studied. Anesthesia was induced and maintained with N20, propofol, and supplementation opioid. Tracheal intubation was accomplished without muscle relaxants. Simultaneous ipsilateral AMG and EMG responses to 0.10 Hz stimulation was recorded. Following instrument calibrations, a single dose of rocuronium was administered. The first patient received a bolus of 0.17 mg kg,1 of rocuronium. Using the Hill equation with a postulated slope of 4.50, the ED50 was calculated. The second subject received a dose which approximated the calculated ED50 for patient no. 1. Successive subjects were given a dose based on the running average of the estimated ED50. Results: The AMG-derived ED50/95 values for rocuronium (0.163 ± 0.055 and 0.314 ± 0.105 mg mg,1) were virtually identical to those established using EMG (0.159 ± 0.043 and 0.306 ± 0.084 mg kg,1). While mean peak twitch depression (,T1) was the same in both groups for individual subjects ,T1 differed by ± 20% (95% confidence interval). Discussion: Acceleromyography-derived twitch heights for individual patients are not necessarily interchangeable with information obtained using electromyography. Nevertheless, acceleromyography appears to be a valid methodology for determining the drug potency when a population rather than an individual subject is being studied. [source]

Ambulatory blood pressure monitoring in pediatric renal transplantation

PEDIATRIC TRANSPLANTATION, Issue 2 2003
Mark M. Mitsnefes
Abstract: Over last two decades ABPM has evolved from a research device to an established and valuable clinical tool for BP evaluation. More than 10 yrs ago ABPM was introduced to pediatrics and since that time, its importance has been increasing in the management of hypertension in children and adolescents. This review summarizes the information gathered from the studies of ABPM in adult and pediatric patients with renal transplants. We will review the importance of hypertension in this patient subset, discuss the advantage of ABPM over CBP and focus on specific abnormalities and clinical significance of ABPM in renal transplant recipients. [source]