Home About us Contact
|
Home About us Contact | ||
|
|
||
Large Section (large + section)
Selected AbstractsResolving the enigma of early coastal settlement in the Hawaiian Islands: The stratigraphic sequence of the Wainiha Beach Site in Kaua'iGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 2 2004Mike T. Carson Archaeological excavation has documented stratified cultural deposits at the Wainiha Beach Site in Kaua'i (Hawaiian Islands), beginning with the occupation of a residential structure dated around A.D. 1030,1400. After about A.D. 1400, the excavated area contains abundant evidence of widespread repeated temporary activities ending in the post-Contact era (post-A.D. 1778). The presence of an early permanent residence followed by a later period of temporary activities opposes conventional understanding of a trend from temporary to permanent occupation in similar sites in the Hawaiian Islands. The complete stratigraphic sequence is disclosed here, with reference to formation processes and depositional context of eight major strata documented in a controlled excavation 0.95 m deep. Various human activities (such as digging pits, trampling, etc.) and periodic natural high-energy events (such as tsunami) appear to have altered the upper portions of underlying deposits. Large sections of the earliest human occupation layer were obliterated, and successive episodes of short-lived activities created numerous inconsistencies in the stratigraphy. These results have important implications for interpreting the cultural sequence not only at Wainiha but also at other rather enigmatic beach sites in the Hawaiian Islands and elsewhere. © 2004 Wiley Periodicals, Inc. [source] Judicial Review of Politics: The Israeli CaseJOURNAL OF LAW AND SOCIETY, Issue 4 2002Daphne Barak In the tradition of studies questioning the impact of celebrated court rulings, this article discusses the effectiveness of the judicial review of politics conducted by the Israeli Supreme Court. The Israeli Supreme Court is generally viewed as a highly influential, almost omnipotent body. During the last two decades, the Court has intervened repeatedly in the so,called political domain, thereby progressively eroding the scope of realms considered non,justiciable. It has ventured to enter domains of ,pure' political power to review the legality of political agreements, political appointments (appointments of political allies to public positions), and political allocations (government funding to organizations affiliated with its political supporters). The prevalent perception is that these developments had a significant impact on Israeli political life. The present article challenges this view and argues that, on closer scrutiny, the influence of the Court on many of the issues reviewed here is negligible. First, many of the doctrines developed by the Court in order to review political measures proved ineffective. Usually, when the Supreme Court (acting as a High Court of Justice) engages in judicial review, it lacks the evidence needed in order to decide that administrative decisions on public appointments or public funding should be abolished because they were based on political or self,serving considerations. Second, the norms mandated by the Court hardly influence politicians' decisions in everyday life, and are applied only in contested cases. The reasons for this situation are not only legal but also socio,political. Large sections of current Israeli society support interest,group politics and do not accept the values that inspire the Court. [source] ACCUMULATING POSTZYGOTIC ISOLATION GENES IN PARAPATRY: A NEW TWIST ON CHROMOSOMAL SPECIATIONEVOLUTION, Issue 3 2003Arcadi Navarro Abstract Chromosomal rearrangements can promote reproductive isolation by reducing recombination along a large section of the genome. We model the effects of the genetic barrier to gene flow caused by a chromosomal rearrangement on the rate of accumulation of postzygotic isolation genes in parapatry. We find that, if reproductive isolation is produced by the accumulation in parapatry of sets of alleles compatible within but incompatible across species, chromosomal rearrangements are far more likely to favor it than classical genetic barriers without chromosomal changes. New evidence of the role of chromosomal rearrangements in parapatric speciation suggests that postzygotic isolation is often due to the accumulation of such incompatibilities. The model makes testable qualitative predictions about the genetic signature of speciation. [source] Broad-scale vegetation-environment relationships in Eurasian high-latitude areasJOURNAL OF VEGETATION SCIENCE, Issue 4 2006Risto Virtanen Hultén & Fries (1986); Ignatov & Afonina (1992); Konstantinova et al. (1992); Vitikainen et al. (1997) Abstract Question: How is tundra vegetation related to climatic, soil chemical, geological variables and grazing across a very large section of the Eurasian arctic area? We were particularly interested in broad-scale vegetation-environment relationships and how well do the patterns conform to climate-vegetation schemes. Material and Methods: We sampled vegetation in 1132 plots from 16 sites from different parts of the Eurasian tundra. Clustering and ordination techniques were used for analysing compositional patterns. Vegetation-environment relationships were analysed by fitting of environmental vectors and smooth surfaces onto non-metric multidimensional scaling scattergrams. Results: Dominant vegetation differentiation was associated with a complex set of environmental variables. A general trend differentiated cold and continental areas from relatively warm and weakly continental areas, and several soil chemical and physical variables were associated with this broad-scaled differentiation. Especially soil chemical variables related to soil acidity (pH, Ca) showed linear relationships with the dominant vegetation gradient. This was closely related to increasing cryoperturbation, decreasing precipitation and cooler conditions. Remarkable differences among relatively adjacent sites suggest that local factors such as geological properties and lemming grazing may strongly drive vegetation differentiation. Conclusions: Vegetation differentiation in tundra areas conforms to a major ecocline underlain by a complex set of environmental gradients, where precipitation, thermal conditions and soil chemical and physical processes are coupled. However, local factors such as bedrock conditions and lemming grazing may cause marked deviations from the general climate-vegetation models. Overall, soil chemical factors (pH, Ca) turned out to have linear relationship with the broad-scale differentiation of arctic vegetation. [source] Documenting hurricane impacts on coral reefs using two-dimensional video-mosaic technologyMARINE ECOLOGY, Issue 2 2007Arthur C. R. Gleason Abstract Four hurricanes impacted the reefs of Florida in 2005. In this study, we evaluate the combined impacts of hurricanes Dennis, Katrina, Rita, and Wilma on a population of Acropora palmata using a newly developed video-mosaic methodology that provides a high-resolution, spatially accurate landscape view of the reef benthos. Storm damage to A. palmata was surprisingly limited; only 2 out of 19 colonies were removed from the study plot at Molasses Reef. The net tissue losses for those colonies that remained were only 10% and mean diameter of colonies decreased slightly from 88.4 to 79.6 cm. In contrast, the damage to the reef framework was more severe, and a large section (6 m in diameter) was dislodged, overturned, and transported to the bottom of the reef spur. The data presented here show that two-dimensional video-mosaic technology is well-suited to assess the impacts of physical disturbance on coral reefs and can be used to complement existing survey methodologies. [source] Liquid chromatography combined with mass spectrometry for 13C isotopic analysis in life science researchMASS SPECTROMETRY REVIEWS, Issue 6 2007Jean-Philippe Godin Abstract Among the different disciplines covered by mass spectrometry, measurement of 13C/12C isotopic ratio crosses a large section of disciplines from a tool revealing the origin of compounds to more recent approaches such as metabolomics and proteomics. Isotope ratio mass spectrometry (IRMS) and molecular mass spectrometry (MS) are the two most mature techniques for 13C isotopic analysis of compounds, respectively, for high and low-isotopic precision. For the sample introduction, the coupling of gas chromatography (GC) to either IRMS or MS is state of the art technique for targeted isotopic analysis of volatile analytes. However, liquid chromatography (LC) also needs to be considered as a tool for the sample introduction into IRMS or MS for 13C isotopic analyses of non-volatile analytes at natural abundance as well as for 13C-labeled compounds. This review presents the past and the current processes used to perform 13C isotopic analysis in combination with LC. It gives particular attention to the combination of LC with IRMS which started in the 1990's with the moving wire transport, then subsequently moved to the chemical reaction interface (CRI) and was made commercially available in 2004 with the wet chemical oxidation interface (LC-IRMS). The LC-IRMS method development is also discussed in this review, including the possible approaches for increasing selectivity and efficiency, for example, using a 100% aqueous mobile phase for the LC separation. In addition, applications for measuring 13C isotopic enrichments using atmospheric pressure LC-MS instruments with a quadrupole, a time-of-flight, and an ion trap analyzer are also discussed as well as a LC-ICPMS using a prototype instrument with two quadrupoles. © 2007 Wiley Periodicals, Inc., Mass Spec Rev 26:751,774, 2007 [source] THE TROUBLE WITH FINAL SALARY PENSION SCHEMESECONOMIC AFFAIRS, Issue 4 2006Nick Silver The decline in final salary pension schemes (FSS) is a result of increasing costs caused in part by legislative interference. In this paper it is argued that FSS have always been detrimental to the economy. In a misguided attempt to save FSS, the government risks bankrupting large sections of the British corporate sector. Other policy measures could allow greater flexibility for trustees of pension schemes and remove counter-productive legislation and encourage innovative market-based solutions to pensions problems. [source] Regeneration as an evolutionary variableJOURNAL OF ANATOMY, Issue 1-2 2001JEREMY P. BROCKES abstract Regeneration poses a distinctive set of problems for evolutionary biologists, but there has been little substantive progress since these issues were clearly outlined in the monograph of T. H. Morgan (1901). The champions at regeneration among vertebrates are the urodele amphibians such as the newt, and we tend to regard urodele regeneration as an exceptional attribute. The ability to regenerate large sections of the body plan is widespread in metazoan phylogeny, although it is not universal. It is striking that in phylogenetic contexts where regeneration occurs, closely related species are observed which do not possess this ability. It is a challenge to reconcile such variation between species with a conventional selective interpretation of regeneration. The critical hypothesis from phylogenetic analysis is that regeneration is a basic, primordial attribute of metazoans rather than a mechanism which has evolved independently in a variety of contexts. In order to explain its absence in closely related species, it is postulated to be lost secondarily for reasons which are not understood. Our approach to this question is to compare a differentiated newt cell with its mammalian counterpart in respect of the plasticity of differentiation. [source] Coupling 3D and 1D fluid-structure interaction models for blood flow simulationsPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2006L. Formaggia Three-dimensional (3D) simulations of blood flow in medium to large vessels are now a common practice. These models consist of the 3D Navier-Stokes equations for incompressible Newtonian fluids coupled with a model for the vessel wall structure. However, it is still computationally unaffordable to simulate very large sections, let alone the whole, of the human circulatory system with fully 3D fluid-structure interaction models. Thus truncated 3D regions have to be considered. Reduced models, one-dimensional (1D) or zero-dimensional (0D), can be used to approximate the remaining parts of the cardiovascular system at a low computational cost. These models have a lower level of accuracy, since they describe the evolution of averaged quantities, nevertheless they provide useful information which can be fed to the more complex model. More precisely, the 1D models describe the wave propagation nature of blood flow and coupled with the 3D models can act also as absorbing boundary conditions. We consider in this work the coupling of a 3D fluid-structure interaction model with a 1D hyperbolic model. We study the stability of the coupling and present some numerical results. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] What role for genetics in the prediction of multiple sclerosis?ANNALS OF NEUROLOGY, Issue 1 2010Stephen Sawcer PhD For most of us, the foundations of our understanding of genetics were laid by considering Mendelian diseases in which familial recurrence risks are high, and mutant alleles are both necessary and sufficient. One consequence of this deterministic teaching is that our conceptualization of genetics tends to be dominated by the notion that the genetic aspects of disease are caused by rare alleles exerting large effects. Unfortunately, the preconceptions that flow from this training are frequently erroneous and misleading in the context of common traits, where familial recurrence risks are modest, and for the most part the relevant alleles are neither rare, necessary, nor sufficient. For these common traits, the genetic architecture is far more complex, with susceptibility rather than causality resulting from the combined effects of many alleles, each exerting only a modest effect on risk. None of these alleles is sufficient to cause disease on its own, and none is essential for the development of disease. Furthermore, most are carried by large sections of the population, the vast majority of which does not develop the disease. One consequence of our innate belief in the Mendelian paradigm is that we have an inherent expectation that knowledge about the genetic basis for a disease should allow genetic testing and thereby accurate risk prediction. There is an inevitable feeling that the same should be true in complex disease, but is it? ANN NEUROL 2010;67:3,10 [source] | |||||||||||||