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Significant Implications (significant + implication)
Selected AbstractsA novel method for evaluation of improved survival trend for common cancer: early detection or improvement of medical careJOURNAL OF EVALUATION IN CLINICAL PRACTICE, Issue 1 2007Wei-Chu Chie PhD Abstract Rationale, aims and objectives, The improvement of survival with time for cancers has been observed worldwide. However, whether and to what extent such an improvement is attributed to early detection or the advance in medical technology is barely addressed. Method, We developed a novel graphic method to calculate attributable proportions related to two factors. This graphic method was first to calculate adjusted survival curve by the application of direct standardized epidemiological method to tumour staging. The crude survival curve was then compared with the adjusted survival curve. Results, Cumulative survival curves of two time epochs, 1989,1993 (period 1) and 1994,1998 (period 2), on six common cancers collected from cancer registry of National Taiwan University between 1989 and 1998, were compared. The attributable proportions due to early detection and medical care were 77% and 23% for breast cancer, 50% and 50% for cervical cancer, 52% and 48% for colorectal cancer, 76% and 24% for gastric cancer, 66% and 34% for liver cancer, and 30% and 70% for prostate cancer respectively. Conclusion, Distinguishing between early detection from advance in medical care associated with the improvement of survival trend using our graphic method has a significant implication for secondary and tertiary prevention of common cancers. [source] Credible collusion in multimarket oligopolyMANAGERIAL AND DECISION ECONOMICS, Issue 2 2007Timothy L. Sorenson This article refines an established explanation of how multimarket contact facilitates collusion when firms enjoy reciprocal advantages across markets: When there are reciprocal asymmetries between firms, multimarket contact allows them not only to develop spheres of influence, but also to implement attractively simple strategies that are subgame perfect and weakly renegotiation proof. Hence, collusive equilibria are supported by fully credible punishments. A significant implication is, multimarket contact involving reciprocal differences between firms may be more facilitating to their cooperative efforts than multimarket contact based on other factors. The article discusses existing empirical work as it relates to this implication. Copyright © 2007 John Wiley & Sons, Ltd. [source] Fuel demand and car ownership modelling in IndiaOPEC ENERGY REVIEW, Issue 1 2007Taoufik Bouachera Motorisation in Asia is soaring with rapid growth in incomes non-lin-early. Even though car ownership per 1,000 population is still low in countries like China, India or Indonesia, escalating number of cars is affected by GDP growth among other infrastructural factors in a non-linear manner. This quick growth in car ownership may represent a significant implication on road transport fuel demand. This paper forecasts the demand for road transport fuel in India. For this purpose, econometric models, based on time series data, are constructed as for a major factor affecting fuel demand in road transportation i.e. car ownership. Firstly the econometric car ownership model was attempted in this study, for projecting future car stock in India based on cross section time series technique. The car stock is modelled by using three functional forms, which are the logistic, quasi-logistic and Gompertz curves. However, to take into consideration countries with different income levels in that part of the world, these models were estimated by using pooled data of seven Asian countries (Japan, China, South Korea, Thailand, Indonesia, Malaysia and India). Then, a set of fuel consumption scenarios were developed in order to make forecast until 2030. These scenarios were generated by taking into consideration car stock, fuel efficiency and the average distance travelled in India. [source] An evaluation of potential diets for the culture of postpueruli spiny lobsters Panulirus argus (Palinuridae)AQUACULTURE NUTRITION, Issue 2 2009S.L. COX Abstract Provision of a suitable feed is paramount for the ongoing success of spiny lobster culture. This study compared and evaluated the performance of seven diets for first instar juvenile spiny lobster Panulirus argus [5,6 mm carapace length (CL)] based on growth rates, survival, and feed conversion ratio. Results demonstrated that a seafood-based juvenile formulation produced the fastest growth rate (3.49% weight gain day,1 and 0.90% CL increase day,1 over a 28-day period). These growth rates were also reflected by a low feed conversion rate (3.04) for this formulated feed. Similar results were also obtained for juveniles fed a frozen seafood diet, however, frozen brine shrimp, Artemia salina (both enriched and un-enriched), frozen enriched mysis shrimp, a dry pellet, and a meal-based juvenile formulation did not produce consistent growth rates. Survival rates ranged between 38% and 85% and demonstrate that juvenile lobsters have better likelihoods of survival in captive culture environments compared to the wild. Although further nutritional refinement is recommended, the results from this research have significant implication for the possible expansion of juvenile spiny lobster growout to a larger scale. [source] An Examination of the Disparity Between Hypothetical and Actual Willingness to Pay Using the Contingent Valuation Method: The Case of Red Kite Conservation in the United KingdomCANADIAN JOURNAL OF AGRICULTURAL ECONOMICS, Issue 2 2007Michael Christie This paper reports the findings of a field experiment that explores the criterion validity of the contingent valuation (CV) method. The empirical experiment examined the disparity between hypothetical and actual willingness to pay (WTP) bids for Red Kite conservation in Wales. Hypothetical WTP was elicited using an open-ended CV instrument, while the actual WTP value was determined from actual donations to the Welsh Kite Trust,a charity set up to aid the conservation of Red Kites in Wales. The survey results indicate that hypothetical WTP was three times greater than the mean value of actual donations; this finding is consistent with a number of other criterion validity experiments. However, we also demonstrate equality of hypothetical and actual WTP among those who actually express a payment amount. Further investigations identify that an underlying cause of this disparity stems from the respondents of the CV survey overstating their intention of pay. This observation has potentially significant implication for CV design in that it suggests that the emphasis in design should be placed much more fully on initially determining whether people would actually pay at all. Le présent article présente les résultats d'une expérience sur le terrain qui a exploré la validité de critère de la méthode d'évaluation contingente (CV). L'expérience empirique a examiné l'écart entre la volonté de payer (VDP) hypothétique et réelle pour la conservation du milan royal dans le pays de Galles. La VDP hypothétique a été obtenue en utilisant un questionnaire ouvert pour effectuer l'évaluation contingente (CV), tandis que la valeur de la VDP réelle a été déterminée d'après les dons réels versés àThe Welsh Kite Trust, organisation caritative créée pour la conservation du milan royal au pays de Galles. Les résultats du sondage ont indiqué que la VDP hypothétique était trois fois supérieures à la valeur moyenne des dons réels; ce résultat rejoint ceux d'autres expériences sur la validité de critère. Cependant, nous avons aussi démontré une égalité entre la VDP hypothétique et réelle des personnes qui ont exprimé le montant du don. Des sondages ultérieurs ont montré qu'une des causes sous-jacentes de cet écart venait du fait que les répondants avaient exagéré leur intention de payer. Cette observation a une implication potentielle importante pour la conception d'évaluation contingente puisqu'elle laisse supposer que l'accent mis sur la conception devrait plutôt être mis sur la détermination initiale de l'intention des personnes à payer ou non. [source] Food Industrialisation and Food Power: Implications for Food GovernanceDEVELOPMENT POLICY REVIEW, Issue 5-6 2003Tim Lang Food supply chains of developed countries industrialised in the second half of the twentieth century, with significant implications for developing countries over policy priorities, the ensuing external costs and the accompanying concentration of market power. Very powerful corporations dominate many sectors. Primary producers are locked into tight specifications and contracts. Consumers may benefit from cheaper food but there are quality implications and health externalities. As consumer confidence has been shaken, new quality agencies have been created. Tensions have emerged about the state's role as facilitator of industrial efficiencies. Food policy is thus torn between the pursuit of productivity and reduced prices and the demand for higher quality, with implications for both producers and consumers in the developing world. [source] Investment and Competition Policy in the WTO: Issues for Developing CountriesDEVELOPMENT POLICY REVIEW, Issue 1 2002Oliver Morrissey This article uses the case of trade-related investment measures (TRIMs) to examine the liberalisation of investment and its potential impact on developing countries. Very few developing countries actually use TRIMs to any appreciable degree, but, when taken in conjunction with the broader liberalisation of investment, the 1994 TRIMs Agreement has significant implications that will constrain governments' policy options and require issues of competition policy to be addressed. Multilateral competition policy would be difficult to agree and implement and the article considers alternative strategies that developing countries could adopt. [source] The sleep of co-sleeping infants when they are not co-sleeping: Evidence that co-sleeping is stressfulDEVELOPMENTAL PSYCHOBIOLOGY, Issue 1 2002Melissa Hunsley Abstract Co-sleeping proponents consider the practice to be "natural" and a potential protection against sudden infant death syndrome (SIDS); others consider the practice of an infant sleeping in the parents' bed for prolonged periods at night to place an infant at risk for harm or death. For this study, co-sleeping was investigated from a different perspective, that is, as a significant early experience to investigate as it may have implications for the infant's development. The sleep of 101 normal, full-term infants was recorded nonintrusively in the home for 24 hr periods when they were 5 weeks and 6 months old. Infants were assigned to three groups: short-term co-sleepers, long-term co-sleepers, and non-co-sleepers. Their sleep states and wakefulness were compared at the two ages and over age. At 5 weeks and 6 months, the long-term co-sleeping infants differed significantly from the non-co-sleepers on a number of measures: At 5 weeks, they showed more quiet sleep and longer bouts of quiet sleep; and at 6 months, they also showed less active sleep, fewer arousals in active sleep, and less wakefulness. Each of these differences indicates a markedly lower arousal level in the long-term co-sleeping infants. This sleep pattern has been repeatedly found to be an indicator of stress. We infer that a major source of stress for these infants is the experience of sleep disturbance documented for infants when they were co-sleeping. Based on extensive evidence for long-term effects of early stress, we conclude that co-sleeping should have significant implications for infants' neurobehavioral development. © 2002 John Wiley & Sons, Inc. Dev Psychobiol 40: 14,22, 2002 [source] Computational fluid dynamics modelling of boundary roughness in gravel-bed rivers: an investigation of the effects of random variability in bed elevationEARTH SURFACE PROCESSES AND LANDFORMS, Issue 4 2001A.P. Nicholas Abstract Results from a series of numerical simulations of two-dimensional open-channel flow, conducted using the computational fluid dynamics (CFD) code FLUENT, are compared with data quantifying the mean and turbulent characteristics of open-channel flow over two contrasting gravel beds. Boundary roughness effects are represented using both the conventional wall function approach and a random elevation model that simulates the effects of supra-grid-scale roughness elements (e.g. particle clusters and small bedforms). Results obtained using the random elevation model are characterized by a peak in turbulent kinetic energy located well above the bed (typically at y/h,=,0·1,0·3). This is consistent with the field data and in contrast to the results obtained using the wall function approach for which maximum turbulent kinetic energy levels occur at the bed. Use of the random elevation model to represent supra-grid-scale roughness also allows a reduction in the height of the near-bed mesh cell and therefore offers some potential to overcome problems experienced by the wall function approach in flows characterized by high relative roughness. Despite these benefits, the results of simulations conducted using the random elevation model are sensitive to the horizontal and vertical mesh resolution. Increasing the horizontal mesh resolution results in an increase in the near-bed velocity gradient and turbulent kinetic energy, effectively roughening the bed. Varying the vertical resolution of the mesh has little effect on simulated mean velocity profiles, but results in substantial changes to the shape of the turbulent kinetic energy profile. These findings have significant implications for the application of CFD within natural gravel-bed channels, particularly with regard to issues of topographic data collection, roughness parameterization and the derivation of mesh-independent solutions. Copyright © 2001 John Wiley & Sons, Ltd. [source] Ecological selection maintains cytonuclear incompatibilities in hybridizing sunflowersECOLOGY LETTERS, Issue 10 2008Julianno B. M. Sambatti Abstract Despite the recent renaissance in studies of ecological speciation, the connection between ecological selection and the evolution of reproductive isolation remains tenuous. We tested whether habitat adaptation of cytoplasmic genomes contributes to the maintenance of reproductive barriers in hybridizing sunflower species, Helianthus annuus and Helianthus petiolaris. We transplanted genotypes of the parental species, reciprocal F1 hybrids and all eight possible backcross combinations of nuclear and cytoplasmic genomes into the contrasting xeric and mesic habitats of the parental species. Analysis of survivorship across two growing seasons revealed that the parental species' cytoplasms were strongly locally adapted and that cytonuclear interactions (CNIs) significantly affected the fitness and architecture of hybrid plants. A significant fraction of the CNIs have transgenerational effects, perhaps due to divergence in imprinting patterns. Our results suggest a common means by which ecological selection may contribute to speciation and have significant implications for the persistence of hybridizing species. [source] Improved 2-DE of microorganisms after acidic extractionELECTROPHORESIS, Issue 8 2006Ben R. Herbert Professor Abstract 2-DE separations of protein extracts sometimes have problems with poor resolution and streaking. This problem is particularly apparent with microorganisms, most notably those with a large cell wall. Here we describe a novel, rapid protocol for the extraction of microorganisms in acidic conditions, leading to increased resolution and 2-D gel quality. The efficiency of the protocol is demonstrated with extracts of bacteria, Escherichia coli and Bacillus subtilis; fungus, Trichoderma harzianum and yeast, Saccharomyces cerevisiae. We also demonstrate using a membrane centrifugal filtration, that large acidic molecules in excess of 100,kDa, probably including cell wall material, are responsible for the separation difficulties. A range of acidic extraction conditions were investigated, and it was found that optimal extraction is achieved using an extraction solution acidified to pH,3 by 80,mM citric acid. These findings have significant implications for the proteomic study of many medically, agriculturally and environmentally significant microorganisms, as the cell walls of these organisms are often considerably more complex than many commonly studied laboratory strains. [source] Horizontal transfer of an exopolymer complex from one bacterial species to anotherENVIRONMENTAL MICROBIOLOGY, Issue 4 2000D. Osterreicher-Ravid Alasan, the exocellular polymeric emulsifier produced by Acinetobacter radioresistens KA53 was shown to bind to the surface of Sphingomonas paucimobilis EPA505 and Acinetobacter calcoaceticus RAG-1. The presence of alasan on the surface of S. paucimobilis EPA505 and A. calcoaceticus RAG-1 caused a decrease in their cell-surface hydrophobicities. Binding was proportional to the concentration of recipient cells and input alasan. At the highest concentration of A. calcoaceticus RAG-1 (4 × 109 ml,1) and alasan (20 µg ml,1) tested, 75% of the alasan was cell bound. Alasan binding was measured by the loss of emulsifying activity and alasan protein and polysaccharide from the aqueous phase after incubation of alasan with the recipient cells. In addition, alasan was visualized on the surface of the recipient cells by staining with anti-alasan antibodies and rhodamine-labelled secondary antibodies. Moreover, when the alasan-producing A. radioresistens KA53 was grown together with A. calcoaceticus RAG-1, alasan was released from the producing strain and became bound to the recipient RAG-1 cells, as demonstrated by fluorescence microscopy. This horizontal transfer of exopolymers from one bacterial species to another has significant implications in natural microbial communities, coaggregation and biofilms. [source] Elucidating the factors influencing the biodegradation of cylindrospermopsin in drinking water sourcesENVIRONMENTAL TOXICOLOGY, Issue 3 2008Maree J. Smith Abstract The cyanotoxin cylindrospermopsin (CYN) is produced by several species of cyanobacteria and can be persistent in drinking waters supplies, which is of major concern to water authorities because of its potential to severely compromise human health. Consequently, there is a need to fully understand the persistence of CYN in water supplies, in particular, to determine whether this toxin is readily degraded by endemic aquatic organisms. This study provides insights into the environmental factors that can influence the biodegradation of this toxin in Australian drinking water supplies. Biodegradation of CYN was only evident in water supplies that had a history of toxic Cylindrospermopsis raciborskii blooms. In addition, lag periods were evident prior to the onset of biodegradation; however, repeated exposure of the endemic organisms to CYN resulted in substantial decreases in the lag periods. Furthermore, the concentration of CYN was shown to influence biodegradation with a near linear relationship (R2 of 0.9549) existing between the biodegradation rate and the initial CYN concentration. Temperature was also shown to affect the biodegradation of CYN, which is important since CYN is now being detected in more temperate climates. The presence of copper-based algicides inhibited CYN degradation, which has significant implications since copper-based algicides are commonly used to control cyanobacterial growth in water bodies. The results from this study indicate that the biodegradation of CYN in natural water bodies is a complex process that can be influenced by many environmental factors, some of which include CYN concentration, temperature, and the presence of copper-based algicides. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2008. [source] Tributyltin uptake and depuration in Hyalella azteca: Implications for experimental designENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2004Adrienne J. Bartlett Abstract The purpose of this study was to address four aspects of the kinetics of tributyltin (TBT) in the freshwater amphipod Hyalella azteca: time to steady state, route of uptake, depuration rates, and effect of gut clearance. The amphipods accumulated TBT rapidly, reaching steady state within 14 d. Body concentrations were similar between caged and sediment-exposed animals, indicating that the primary route of uptake is via dissolved TBT. However, the rate of uptake was significantly higher in sediment-exposed amphipods. During depuration, body concentrations of TBT exhibited a biphasic decline, with a stronger decrease over the first 24 h that is attributed primarily to gut clearance, followed by a more gradual decrease most likely due to excretion from the body. Gut contents contributed significantly to body concentrations of TBT, accounting for 30% of the initial total body burden in sediment-exposed amphipods. Half-lives of TBT in gut-cleared H. azteca were 8 d and 14 d for amphipods exposed to spiked water and spiked sediment, respectively. The results of this study have significant implications in the experimental design and interpretation of studies involving the effects of TBT in H. azteca. [source] Extensive HLA class I allele promiscuity among viral CTL epitopesEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 9 2007Nicole Frahm Abstract Promiscuous binding of T helper epitopes to MHC class II molecules has been well established, but few examples of promiscuous class I-restricted epitopes exist. To address the extent of promiscuity of HLA class I peptides, responses to 242 well-defined viral epitopes were tested in 100 subjects regardless of the individuals' HLA type. Surprisingly, half of all detected responses were seen in the absence of the originally reported restricting HLA class I allele, and only 3% of epitopes were recognized exclusively in the presence of their original allele. Functional assays confirmed the frequent recognition of HLA class I-restricted T cell epitopes on several alternative alleles across HLA class I supertypes and encoded on different class I loci. These data have significant implications for the understanding of MHC class I-restricted antigen presentation and vaccine development. [source] REVIEW: Modeling stress and drug craving in the laboratory: implications for addiction treatment developmentADDICTION BIOLOGY, Issue 1 2009Rajita Sinha ABSTRACT Addition is a chronic relapsing illness affected by multiple social, individual and biological factors that significantly impact course and recovery of the illness. Stress interacts with these factors and increases addiction vulnerability and relapse risk, thereby playing a significant role in the course of the illness. This paper reviews our efforts in developing and validating laboratory models of stress and drug cue-related provocation to assess stress responses and stress-related adaptation in addicted individuals compared with healthy controls. Empirical findings from human laboratory and brain imaging studies are presented to show the specific stress-related dysregulation that accompanies the drug-craving state in addicted individuals. In order to adequately validate our laboratory model, we have also carefully examined relapse susceptibility in the addicted individuals and these data are reviewed. The overarching goal of these efforts is to develop a valid laboratory model to identify the stress-related pathophysiology in addiction with specific regard to persistent craving and compulsive seeking. Finally, the significant implications of these findings for the development of novel treatment interventions that target stress processes and drug craving to improve addiction relapse outcomes are discussed. [source] Fear learning induces persistent facilitation of amygdala synaptic transmissionEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2005Bradley W. Schroeder Abstract In the maintenance phase of fear memory, synaptic transmission is potentiated and the stimulus requirements and signalling mechanisms are altered for long-term potentiation (LTP) in the cortico-lateral amygdala (LA) pathway. These findings link amygdala synaptic plasticity to the coding of fear memories. Behavioural experiments suggest that the amygdala serves to store long-term fear memories. Here we provide electrophysiological evidence showing that synaptic alterations in rats induced by fear conditioning are evident in vitro 10 days after fear conditioning. We show that synaptic transmission was facilitated and that high-frequency stimulation dependent LTP (HFS,LTP) of the cortico-lateral amygdala pathway remained attenuated 10 days following fear conditioning. Additionally, we found that the low-frequency stimulation dependent LTP (LFS,LTP) measured 24 h after fear conditioning was absent 10 days post-training. The persistent facilitation of synaptic transmission and occlusion of HFS,LTP suggests that, unlike hippocampal coding of contextual fear memory, the cortico-lateral amygdala synapse is involved in the storage of long-term fear memories. However, the absence of LFS,LTP 10 days following fear conditioning suggests that amygdala physiology 1 day following fear learning may reflect a dynamic state during memory stabilization that is inactive during the long-term storage of fear memory. Results from these experiments have significant implications regarding the locus of storage for maladaptive fear memories and the synaptic alterations induced by these memories. [source] MULTILEVEL SELECTION AND THE PARTITIONING OF COVARIANCE: A COMPARISON OF THREE APPROACHESEVOLUTION, Issue 3 2004Samir Okasha Abstract Where the evolution of a trait is affected by selection at more than one hierarchical level, it is often useful to compare the magnitude of selection at each level by asking how much of the total evolutionary change is attributable to each level of selection. Three statistical partitioning techniques, each designed to answer this question, are compared, in relation to a simple multilevel selection model in which a trait's evolution is affected by both individual and group selection. None of the three techniques is wholly satisfactory: one implies that group selection can operate even if individual fitness is determined by individual phenotype alone, whereas the other two imply that group selection can operate even if there is no variance in group fitness. This has significant implications both for our understanding of what the term "multilevel selection" means and for the traditional concept of group selection. [source] Summer drought decreases soil fungal diversity and associated phenol oxidase activity in upland Calluna heathland soilFEMS MICROBIOLOGY ECOLOGY, Issue 2 2008Hannah Toberman Abstract Natural moisture limitation during summer drought can constitute a stress for microbial communities in soil. Given globally predicted increases in drought frequency, there is an urgent need for a greater understanding of the effects of drought events on soil microbial processes. Using a long-term field-scale drought manipulation experiment at Clocaenog, Wales, UK, we analysed fungal community dynamics, using internal transcribed spacer-denaturing gradient gel electrophoresis (DGGE), over a 1-year period in the 6th year of drought manipulation. Ambient seasonality was found to be the dominant factor driving variation in fungal community dynamics. The summer drought manipulation resulted in a significant decline in the abundance of dominant fungal species, both independently of, and in interaction with, this seasonal variation. Furthermore, soil moisture was significantly correlated with the changes in fungal diversity over the drought manipulation period. While the relationship between species diversity and functional diversity remains equivocal, phenol oxidase activity was decreased by the summer drought conditions and there was a significant correlation with the decline of DGGE band richness among the most dominant fungal species during the drought season. Climatically driven events such as droughts may have significant implications for fungal community diversity and therefore, have the potential to interfere with crucial ecosystem processes, such as organic matter decomposition. [source] Multifunctional Dendrimer-Templated Antibody Presentation on Biosensor Surfaces for Improved Biomarker DetectionADVANCED FUNCTIONAL MATERIALS, Issue 3 2010Hye Jung Han Abstract Dendrimers, with their well-defined globular shape and high density of functional groups, are ideal nanoscale materials for templating sensor surfaces. This work exploits dendrimers as a versatile platform for capturing biomarkers with improved sensitivity and specificity. The synthesis, characterization, fabrication, and functional validation of the dendrimer-based assay platform are described. Bifunctional hydroxyl/thiol-functionalized G4-polyamidoamine (PAMAM) dendrimer is synthesized and immobilized on the polyethylene-glycol (PEG)-functionalized assay plate by coupling PEG-maleimide and dendrimer thiol groups. Simultaneously, part of the dendrimer thiol groups are converted to hydrazide functionalities. The resulting dendrimer-modified surface is coupled to the capture antibody in the Fc region of the oxidized antibody. This preserves the orientation flexibility of the antigen binding region (Fv) of the antibody. To validate the approach, the fabricated plates are further used as a solid phase for developing a sandwich-type enzyme-linked immunosorbent assay (ELISA) to detect IL-6 and IL-1,, important biomarkers for early stages of chorioamnionitis. The dendrimer-modified plate provides assays with significantly enhanced sensitivity, lower nonspecific adsorption, and a detection limit of 0.13,pg,mL,1 for IL-6 luminol detection and 1.15,pg,mL,1 for IL-1, TMB detection, which are significantly better than those for the traditional ELISA. The assays were validated in human serum samples from a normal (nonpregnant) woman and pregnant women with pyelonephritis. The specificity and the improved sensitivity of the dendrimer-based capture strategy could have significant implications for the detection of a wide range of cytokines and biomarkers since the capture strategy could be applied to multiplex microbead assays, conductometric immunosensors, and field-effect biosensors. [source] Relevance of the genes for bone mass variation to susceptibility to osteoporotic fractures and its implications to gene search for complex human diseasesGENETIC EPIDEMIOLOGY, Issue 1 2002Hong-Wen Deng Abstract We investigate the relevance of the genetic determination of bone mineral density (BMD) variation to that of differential risk to osteoporotic fractures (OF). The high heritability (h2) of BMD and the significant phenotypic correlations between high BMD and low risk to OF are well known. Little is reported on h2 for OF. Extensive molecular genetic studies aimed at uncovering genes for differential risks to OF have focussed on BMD as a surrogate phenotype. However, the relevance of the genetic determination of BMD to that of OF is unknown. This relevance can be characterized by genetic correlation between BMD and OF. For 50 Caucasian pedigrees, we estimated that h2 at the hip is 0.65 (P < 0.0001) for BMD and 0.53 (P < 0.05) for OF; however, the genetic correlation between BMD and OF is nonsignificant (P > 0.45) and less than 1% of additive genetic variance is shared between them. Hence, most genes found important for BMD may not be relevant to OF at the hip. The phenotypic correlation between high BMD and low risk to OF at the hip (approximately ,0.30) is largely due to an environmental correlation (,E = ,0.73, P < 0.0001). The search for genes for OF should start with a significant h2 for OF and should include risk factors (besides BMD) that are genetically correlated with OF. All genes found important for various risk factors must be tested for their relevance to OF. Ideally, employing OF per se as a direct phenotype for gene hunting and testing can ensure the importance and direct relevance of the genes found for the risk of OF. This study may have significant implications for the common practice of gene search for complex diseases through underlying risk factors (usually quantitative traits). Genet. Epidemiol. 22:12,25, 2002. © 2002 Wiley-Liss, Inc. [source] Archaeological mounds in Marajó Island in northern Brazil: A geological perspective integrating remote sensing and sedimentologyGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 1 2009Dilce de Fátima Rossetti Earthen mounds with archaeological artifacts have been well known in Marajó Island since the 19th century. Their documented dimensions are impressive, e.g., up to 20 m high, and with areas as large as 90 ha. The mounds, locally known as tesos, impose a significant relief on the very low-lying landscape of this region, which averages 4 to 6m above present sea level. These features have been traditionally interpreted as artificial constructions of the Marajoara culture, designed for defense, cemetery purposes, or escape from flooding. Here, we provide sedimentological and geomorphological data that suggest an alternative origin for these structures that is more consistent with their monumental sizes. Rather than artificial, the Marajoara tesos seem to consist of natural morphological features related to late Pleistocene and Holocene fluvial, and possibly tidal-influenced, paleochannels and paleobars that became abandoned as depositional conditions changed through time. Although utilized and modified by the Marajoara since at least 2000 years ago, these earthen mounds contain a significant non-anthropogenically modified sedimentary substratum. Therefore, the large Marajoara tesos are not entirely artificial. Ancient Marajoara cultures took advantage of these natural, preexisting elevated surfaces to base their communities and develop their activities, locally increasing the sizes of these fluvial landforms. This alternative interpretation suggests less cumulative labor investment in the construction of the mounds and might have significant implications for reconstructing the organization of the Marajoara culture. © 2009 Wiley Periodicals, Inc. [source] Romarchite and associated phases as common corrosion products on pewter artifacts from marine archaeological sitesGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 6 2004Stacie E. Dunkle Corrosion products were examined from typical pewter artifacts originating from six different submerged archaeological sites, dating to between ca. A.D. 1550 and 1733, along the eastern seaboard of North America and in the Caribbean Sea. The artifacts were viewed as 270,450-year long experiments revealing the phases and mechanisms of tin corrosion in seawater. All of the samples analyzed exhibit abhurite (Sn3O(OH)2Cl2), romarchite (SnO), and hydroromarchite (Sn3O2(OH)2) forming at the expense of the underlying artifact. Textural analysis suggests that abhurite is the first alteration product to form at the expense of the pewter; romarchite subsequently develops and then hydroromarchite. The outermost corrosion layers on several of the most corroded artifacts also exhibit cassiterite (SnO2) as a significant and apparently final phase to form during alteration. The absence of this mineral on many samples demonstrates that, while samples appeared to be stable under the conditions that were present, cassiterite had not yet had time to form. The very limited stability field for romarchite, based on data presented by Séby et al. (Geochimica et Cosmochimica Acta, 65, 3041,3053, 2001), suggests that its presence on these artifacts may be the result of a kinetic effect. The universal appearance of this mineral on corroding tin suggests that it is a required step in the oxidation of pure tin to the final most stable phase of cassiterite. The stability of romarchite and its effectiveness as an agent of passivation can provide insight into not only the formation of tin oxides but the rate of tin corrosion. This can have significant implications in the field of artifact preservation as well as more widespread industrial applications. © 2004 Wiley Periodicals, Inc. [source] Soil parent materials and the pottery of Roman Galilee: A comparative studyGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 4 2002Moshe Wieder The paper presents a comparative micromorphological analysis of the range of soil materials used to make the pottery of the hilly Galilee during the Roman period, and the ceramic products made from these materials. The four soil units that served as raw material for most of the pottery made in this period and region are examined along with pottery derived from each of them. For each soil unit, the soil characteristics and processes are described, followed by a presentation of the micromorphological characteristics of the soil material and those of the pottery made from that material. The contribution of the aeolian dust component to the soil materials is discussed as well as the identification of the tempering materials (nonplastics or other soil materials) added to the pottery paste. The study demonstrates the close correlation in microfabric between the pottery and original soil materials, sheds light on the raw material selection and modification practices of the potters of Roman Galilee, and has significant implications for provenance studies, using chemical analysis, on the pottery of this period and region. © 2002 Wiley Periodicals, Inc. [source] Water savings in mature deciduous forest trees under elevated CO2GLOBAL CHANGE BIOLOGY, Issue 12 2007SEBASTIAN LEUZINGER Abstract Stomatal conductance of plants exposed to elevated CO2 is often reduced. Whether this leads to water savings in tall forest-trees under future CO2 concentrations is largely unknown but could have significant implications for climate and hydrology. We used three different sets of measurements (sap flow, soil moisture and canopy temperature) to quantify potential water savings under elevated CO2 in a ca. 35 m tall, ca. 100 years old mixed deciduous forest. Part of the forest canopy was exposed to 540 ppm CO2 during daylight hours using free air CO2 enrichment (FACE) and the Swiss Canopy Crane (SCC). Across species and a wide range of weather conditions, sap flow was reduced by 14% in trees subjected to elevated CO2, yielding ca. 10% reduction in evapotranspiration. This signal is likely to diminish as atmospheric feedback through reduced moistening of the air comes into play at landscape scale. Vapour pressure deficit (VPD)-sap flow response curves show that the CO2 effect is greatest at low VPD, and that sap flow saturation tends to occur at lower VPD in CO2 -treated trees. Matching stomatal response data, the CO2 effect was largely produced by Carpinus and Fagus, with Quercus contributing little. In line with these findings, soil moisture at 10 cm depth decreased at a slower rate under high-CO2 trees than under control trees during rainless periods, with a reversal of this trend during prolonged drought when CO2 -treated trees take advantage from initial water savings. High-resolution thermal images taken at different heights above the forest canopy did detect reduced water loss through altered energy balance only at <5 m distance (0.44 K leaf warming of CO2 -treated Fagus trees). Short discontinuations of CO2 supply during morning hours had no measurable canopy temperature effects, most likely because the stomatal effects were small compared with the aerodynamic constraints in these dense, broad-leaved canopies. Hence, on a seasonal basis, these data suggest a <10% reduction in water consumption in this type of forest when the atmosphere reaches 540% ppm CO2. [source] C4-derived soil organic carbon decomposes faster than its C3 counterpart in mixed C3/C4 soilsGLOBAL CHANGE BIOLOGY, Issue 10 2007JONATHAN G. WYNN Abstract The large difference in the degree of discrimination of stable carbon isotopes between C3 and C4 plants is widely exploited in global change and carbon cycle research, often with the assumption that carbon retains the carbon isotopic signature of its photosynthetic pathway during later stages of decomposition in soil and sediments. We applied long-term incubation experiments and natural 13C-labelling of C3 and C4-derived soil organic carbon (SOC) collected from across major environmental gradients in Australia to elucidate a significant difference in the rate of decomposition of C3- and C4-derived SOC. We find that the active pool of SOC (ASOC) derived from C4 plants decomposes at over twice the rate of the total pool of ASOC. As a result, the proportion of C4 photosynthesis represented in the heterotrophic CO2 flux from soil must be over twice the proportional representation of C4-derived biomass in SOC. This observation has significant implications for much carbon cycle research that exploits the carbon isotopic difference in these two photosynthetic pathways. [source] Coral bleaching, reef fish community phase shifts and the resilience of coral reefsGLOBAL CHANGE BIOLOGY, Issue 9 2006DAVID R. BELLWOOD Abstract The 1998 global coral bleaching event was the largest recorded historical disturbance of coral reefs and resulted in extensive habitat loss. Annual censuses of reef fish community structure over a 12-year period spanning the bleaching event revealed a marked phase shift from a prebleach to postbleach assemblage. Surprisingly, we found that the bleaching event had no detectable effect on the abundance, diversity or species richness of a local cryptobenthic reef fish community. Furthermore, there is no evidence of regeneration even after 5,35 generations of these short-lived species. These results have significant implications for our understanding of the response of coral reef ecosystems to global warming and highlight the importance of selecting appropriate criteria for evaluating reef resilience. [source] Impact of CO2 concentration changes on the biosphere-atmosphere system of West AfricaGLOBAL CHANGE BIOLOGY, Issue 12 2002GUILING WANG Abstract Vegetation dynamics plays a critical role in causing the decadal variability of precipitation over the Sahel region of West Africa. However, the potential impact of changes in CO2 concentration on vegetation dynamics and precipitation variability of this region has not been addressed by previous studies. In this paper, we explore the role of CO2 concentration in the regional climate system of West Africa using a zonally symmetric, synchronously coupled biosphere-atmosphere model. We first document the response of precipitation and vegetation to incremental changes of CO2 concentration; the impact of CO2 concentration on the variability of the regional biosphere-atmosphere system is then addressed using the second half of the twentieth century as an example. An increase of CO2 concentration causes the regional biosphere-atmosphere system to become wetter and greener, with the radiative effect of CO2 and improved plant-water relation dominant in the Sahelian grassland region and the direct enhancement of leaf carbon assimilation dominant in the tree-covered region to the south. Driven by the observed sea surface temperature (SST) of the tropical Atlantic Ocean during the period 1950,97 and with CO2 concentration prescribed at a pre-industrial level 300ppmv, the model simulates a persistent Sahel drought during the period of 1960s,1990s. The simulated drought takes place in the form of a transition of the coupled biosphere-atmosphere system from a wet/green regime in the 1950s to a dry/barren regime after the 1960s. This climate transition is triggered by SST forcing and materialized through vegetation-climate interactions. The same SST forcing does not produce such a persistent drought when a constant modern CO2 concentration of 350ppmv is specified, indicating that the biosphere-atmosphere system at higher CO2 level is more resilient to drought-inducing external forcings. This finding suggests that the regional climate in Sahel, which tends to alternate between dry and wet spells, may experience longer (or more frequent) wet episodes and shorter (or less frequent) dry episodes in the future than in the past. Our study has significant implications regarding the impact of climate change on regional socio-economic development. [source] Variegated neoliberalization: geographies, modalities, pathwaysGLOBAL NETWORKS, Issue 2 2010NEIL BRENNER Abstract Across the broad field of heterodox political economy, ,neoliberalism' appears to have become a rascal concept , promiscuously pervasive, yet inconsistently defined, empirically imprecise and frequently contested. Controversies regarding its precise meaning are more than merely semantic. They generally flow from underlying disagreements regarding the sources, expressions and implications of contemporary regulatory transformations. In this article, we consider the handling of ,neoliberalism' within three influential strands of heterodox political economy , the varieties of capitalism approach; historical materialist international political economy; and governmentality approaches. While each of these research traditions sheds light on contemporary processes of market-oriented regulatory restructuring, we argue that each also underplays and/or misreads the systemically uneven, or ,variegated', character of these processes. Enabled by a critical interrogation of how each approach interprets the geographies, modalities and pathways of neoliberalization processes, we argue that the problematic of variegation must be central to any adequate account of marketized forms of regulatory restructuring and their alternatives under post-1970s capitalism. Our approach emphasizes the cumulative impacts of successive ,waves' of neoliberalization upon uneven institutional landscapes, in particular: (a) their establishment of interconnected, mutually recursive policy relays within an increasingly transnational field of market-oriented regulatory transfer; and (b) their infiltration and reworking of the geoinstitutional frameworks, or ,rule regimes', within which regulatory experimentation unfolds. This mode of analysis has significant implications for interpreting the current global economic crisis. [source] Company-based education programmes: what's the pay-off for employers?HUMAN RESOURCE MANAGEMENT JOURNAL, Issue 4 2001Graeme Martin This article addresses the question of whether company-based programmes of education repay employer investment in terms of learning transfer to the workplace. Building on earlier work by the authors, we use an in-depth longitudinal case study of a long-standing programme of continuous education sponsored by the US-based NCR corporation in Scotland. As educators, we expected to find that the programme would have been associated with positive outcomes, based on the belief that 'embrained' or formal, abstract knowledge can be transferred to the workplace. We were aware, however, that research in this area has not been promising in demonstrating learning transfer, in part because such a process is mediated by the quality of the transfer climate. Drawing on survey data and in-depth interviewing of a sample cohort, we found that the programme of company-based education had significant implications for learning transfer. Surprisingly, however, transfer climate had little influence on the willingness of employees to use their knowledge to make improvements or generate innovations at work. Finally, we found that these data supported situated learning theory, stressing the importance of tacit knowledge, informal learning, the communal nature of workplace learning and the difficulties in evaluating learning transfer. We believe that these results have important implications for the literature on the evaluation of HRD interventions, for human resource development (HRD) specialists interested in developing programmes of so-called lifelong learning and for practitioners working in the area of organisational learning and learning organisations. [source] | ||||||||||||||||||||||||||||||||||||||||