bluuebunny/crossref_metadata_2025 huggingface dataset:
Evolutionary concepts in predicting and evaluating the impact of mass chemotherapy schistosomiasis control programmes on parasites and their hosts
Authors: Webster Joanne P. , Gower Charlotte M. , Norton Alice J.
Published: January 2008

Schistosomiasis is a parasitic disease of significant medical and veterinary importance in many regions of the world. Recent shifts in global health policy have led towards the implementation of mass chemotherapeutic control programmes at the national scale in previously ‘neglected’ countries such as those within sub‐Saharan Africa. Evolutionary theory has an important role to play in the design, application and interpretation of such programmes. Whilst celebrating the rapid success achieved to date by such programmes, in terms of reduced infection prevalence, intensity and associated human morbidity, evolutionary change in response to drug selection pressure may be predicted under certain circumstances, particularly in terms of the development of potential drug resistance, evolutionary changes in parasite virulence, transmission and host use, and/or competitive interactions with co‐infecting pathogens. Theoretical and empirical data gained to date serve to highlight the importance of careful monitoring and evaluation of parasites and their hosts whenever and wherever chemotherapy is applied and where parasite transmission remains.
Adaptation, migration or extirpation: climate change outcomes for tree populations
Authors: Aitken Sally N. , Yeaman Sam , Holliday Jason A. , Wang Tongli , Curtis‐McLane Sierra
Published: January 2008

Species distribution models predict a wholesale redistribution of trees in the next century, yet migratory responses necessary to spatially track climates far exceed maximum post‐glacial rates. The extent to which populations will adapt will depend upon phenotypic variation, strength of selection, fecundity, interspecific competition, and biotic interactions. Populations of temperate and boreal trees show moderate to strong clines in phenology and growth along temperature gradients, indicating substantial local adaptation. Traits involved in local adaptation appear to be the product of small effects of many genes, and the resulting genotypic redundancy combined with high fecundity may facilitate rapid local adaptation despite high gene flow. Gene flow with preadapted alleles from warmer climates may promote adaptation and migration at the leading edge, while populations at the rear will likely face extirpation. Widespread species with large populations and high fecundity are likely to persist and adapt, but will likely suffer adaptational lag for a few generations. As all tree species will be suffering lags, interspecific competition may weaken, facilitating persistence under suboptimal conditions. Species with small populations, fragmented ranges, low fecundity, or suffering declines due to introduced insects or diseases should be candidates for facilitated migration.
The C‐terminus of Kv7 channels: a multifunctional module
Authors: Haitin Yoni , Attali Bernard
Published: January 2008

Kv7 channels (KCNQ) represent a family of voltage‐gated K+ channels which plays a prominent role in brain and cardiac excitability. Their physiological importance is underscored by the existence of mutations in human Kv7 genes, leading to severe cardiovascular and neurological disorders such as the cardiac long QT syndrome and neonatal epilepsy. Kv7 channels exhibit some structural and functional features that are distinct from other Kv channels. Notably, the Kv7 C‐terminus is long compared to other K+ channels and is endowed with characteristic structural domains, including coiled‐coils, amphipatic α helices containing calmodulin‐binding motifs and basic amino acid clusters. Here we provide a brief overview of current insights and as yet unsettled issues about the structural and functional attributes of the C‐terminus of Kv7 channels. Recent data indicate that the proximal half of the Kv7 C‐terminus associates with one calmodulin constitutively bound to each subunit. Epilepsy and long QT mutations located in this proximal region impair calmodulin binding and can affect channel gating, folding and trafficking. The distal half of the Kv7 C‐terminus directs tetramerization, employing tandem coiled‐coils. Together, the data indicate that the Kv7 C‐terminal domain is a multimodular structure playing a crucial role in channel gating, assembly and trafficking as well as in scaffolding the channel complex with signalling proteins.
Temporal changes in the involvement of pyruvate dehydrogenase complex in muscle lactate accumulation during lipopolysaccharide infusion in rats
Authors: Alamdari N. , Constantin‐Teodosiu D. , Murton A. J. , Gardiner S. M. , Bennett T. , Layfield R. , Greenhaff P. L.
Published: January 2008

A characteristic manifestation of sepsis is muscle lactate accumulation. This study examined any putative (causative) association between pyruvate dehydrogenase complex (PDC) inhibition and lactate accumulation in the extensor digitorum longus (EDL) muscle of rats infused with lipopolysaccharide (LPS), and explored the involvement of increased transcription of muscle‐specific pyruvate dehydrogenase kinase (PDK) isoenzymes. Conscious, male Sprague–Dawley rats were infused i.v. with saline (0.4 ml h−1, control) or LPS (150 μg kg−1 h−1) for 2 h, 6 h or 24 h (n= 6–8). Muscle lactate concentration was elevated after 2, 6 and 24 h LPS infusion. Muscle PDC activity was the same at 2 h and 6 h, but was 65% lower after 24 h of LPS infusion (P < 0.01), when there was a 47% decrease in acetylcarnitine concentration (P < 0.05), and a 24‐fold increase in PDK4 mRNA expression (P < 0.001). These changes were preceded by marked increases in tumour necrosis factor‐α and interleukin‐6 mRNA expression at 2 h. The findings indicate that the early (2 and 6 h) elevation in muscle lactate concentration during LPS infusion was not attributable to limited muscle oxygen availability or ATP production (evidenced by unchanged ATP and phosphocreatine (PCr) concentrations) or to PDC inhibition, whereas after 24 h, muscle lactate accumulation appears to have resulted from PDC activation status limiting pyruvate flux, most probably due to cytokine‐mediated up‐regulation of PDK4 transcription.
Innate Immune Homeostasis by the Homeobox Gene
Caudal
and Commensal-Gut Mutualism in
Drosophila
Authors: Ryu Ji-Hwan , Kim Sung-Hee , Lee Hyo-Young , Bai Jin Young , Nam Young-Do , Bae Jin-Woo , Lee Dong Gun , Shin Seung Chul , Ha Eun-Mi , Lee Won-Jae
Published: January 2008

Although commensalism with gut microbiota exists in all metazoans, the host factors that maintain this homeostatic relationship remain largely unknown. We show that the intestinal homeobox gene
Caudal
regulates the commensal-gut mutualism by repressing nuclear factor kappa B–dependent antimicrobial peptide genes. Inhibition of
Caudal
expression in flies via RNA interference led to overexpression of antimicrobial peptides, which in turn altered the commensal population within the intestine. In particular, the dominance of one gut microbe,
Gluconobacter
sp. strain EW707, eventually led to gut cell apoptosis and host mortality. However, restoration of a healthy microbiota community and normal host survival in the
Caudal-RNAi
flies was achieved by reintroduction of the
Caudal
gene. These results reveal that a specific genetic deficiency within a host can profoundly influence the gut commensal microbial community and host physiology.
Chemically Derived, Ultrasmooth Graphene Nanoribbon Semiconductors
Authors: Li Xiaolin , Wang Xinran , Zhang Li , Lee Sangwon , Dai Hongjie
Published: January 2008

We developed a chemical route to produce graphene nanoribbons (GNR) with width below 10 nanometers, as well as single ribbons with varying widths along their lengths or containing lattice-defined graphene junctions for potential molecular electronics. The GNRs were solution-phase–derived, stably suspended in solvents with noncovalent polymer functionalization, and exhibited ultrasmooth edges with possibly well-defined zigzag or armchair-edge structures. Electrical transport experiments showed that, unlike single-walled carbon nanotubes, all of the sub–10-nanometer GNRs produced were semiconductors and afforded graphene field effect transistors with on-off ratios of about 10
7
at room temperature.
PilB and PilT Are ATPases Acting Antagonistically in Type IV Pilus Function inMyxococcus xanthus
Authors: Jakovljevic Vladimir , Leonardy Simone , Hoppert Michael , Søgaard-Andersen Lotte
Published: January 2008

Type IV pili (T4P) are dynamic surface structures that undergo cycles of extension and retraction. T4P dynamics center on the PilB and PilT proteins, which are members of the secretion ATPase superfamily of proteins. Here, we show that PilB and PilT of the T4P system inMyxococcus xanthushave ATPase activity in vitro. Using a structure-guided approach, we systematically mutagenized PilB and PilT to resolve whether both ATP binding and hydrolysis are important for PilB and PilT function in vivo. PilB as well as PilT ATPase activity was abolished in vitro by replacement of conserved residues in the Walker A and Walker B boxes that are involved in ATP binding and hydrolysis, respectively. PilB proteins containing mutant Walker A or Walker B boxes were nonfunctional in vivo and unable to support T4P extension. PilT proteins containing mutant Walker A or Walker B boxes were also nonfunctional in vivo and unable to support T4P retraction. These data provide genetic evidence that both ATP binding and hydrolysis by PilB are essential for T4P extension and that both ATP binding and hydrolysis by PilT are essential for T4P retraction. Thus, PilB and PilT are ATPases that act at distinct steps in the T4P extension/retraction cycle in vivo.
Molecular and Physiological Role of the Trehalose-Hydrolyzing α-Glucosidase from
Thermus thermophilus
HB27
Authors: Alarico Susana , da Costa Milton S. , Empadinhas Nuno
Published: January 2008

Trehalose supports the growth of
Thermus thermophilus
strain HB27, but the absence of obvious genes for the hydrolysis of this disaccharide in the genome led us to search for enzymes for such a purpose. We expressed a putative α-glucosidase gene (TTC0107), characterized the recombinant enzyme, and found that the preferred substrate was α,α-1,1-trehalose, a new feature among α-glucosidases. The enzyme could also hydrolyze the disaccharides kojibiose and sucrose (α-1,2 linkage), nigerose and turanose (α-1,3), leucrose (α-1,5), isomaltose and palatinose (α-1,6), and maltose (α-1,4) to a lesser extent. Trehalose was not, however, a substrate for the highly homologous α-glucosidase from
T. thermophilus
strain GK24. The reciprocal replacement of a peptide containing eight amino acids in the α-glucosidases from strains HB27 (LGEHNLPP) and GK24 (EPTAYHTL) reduced the ability of the former to hydrolyze trehalose and provided trehalose-hydrolytic activity to the latter, showing that LGEHNLPP is necessary for trehalose recognition. Furthermore, disruption of the α-glucosidase gene significantly affected the growth of
T. thermophilus
HB27 in minimal medium supplemented with trehalose, isomaltose, sucrose, or palatinose, to a lesser extent with maltose, but not with cellobiose (not a substrate for the α-glucosidase), indicating that the α-glucosidase is important for the assimilation of those four disaccharides but that it is also implicated in maltose catabolism.
Deciphering superimposed Ellesmerian and Eurekan deformation, Piper Pass area, northern Ellesmere Island (Nunavut)
Authors: Piepjohn Karsten , Gosen Werner von , Estrada Solveig , Tessensohn Franz
Published: January 2008

The tectonic evolution in the Piper Pass area in northern Ellesmere Island (Canadian Arctic) is characterized by the superimposition of two major deformational events: the Paleozoic Ellesmerian Orogeny and the Tertiary Eurekan deformation. It is difficult to separate the structures formed during each deformation in the parts of the Canadian Arctic in which the post-Ellesmerian and pre-Eurekan Sverdrup Basin is not preserved (Hazen Fold Belt, Central Ellesmere Fold Belt). In the vicinity of the Lake Hazen Fault Zone in the Piper Pass area, kilometre-scale kink folds, cleavage planes and SSE-directed thrust faults are unconformably overlain by Permian through Tertiary rocks of the Sverdrup Basin, which clearly indicates that they are related to the Ellesmerian Orogeny. However, the steep faults of the Lake Hazen Fault Zone are characterized by possible lateral movements and by NNW–SSE compression that cut through or affect both the pre-Ellesmerian Franklinian strata, as well as the post-Ellesmerian Sverdrup Basin deposits. These structures can clearly be assigned to post-mid Cretaceous movements of the Eurekan deformation. The Piper Pass area is a key area in which it is possible to recognize and distinguish Ellesmerian from Eurekan structures.
Ontogeny of Parabolinella panosa (Olenidae, Trilobita) from the uppermost Furongian (Upper Cambrian) of northwestern Canada, with discussion of olenid protaspides
Authors: Lee Dong-Chan , Chatterton Brian D.E.
Published: January 2008

The ontogeny of Parabolinella panosa (the Family Olenidae) from the uppermost Furongian (Upper Cambrian) of the Rabbitkettle Formation, MacKenzie Mountains, northwestern Canada, is described. The protaspides are characterized by a highly convex lateral profile, parallel-sided axial furrows, and three pairs of fixigenal spines. Protaspid morphologies of eight olenid species, including P. panosa, demonstrate that the Olenidae, a widely accepted monophyletic group, displays surprisingly disparate morphologies during the protaspid period. The olenid protaspides show morphologic differences according to oxygenation conditions; the olenid protaspides from poorly oxygenated environments are smaller in size, and have a spindle-shaped axis, distinct anterior pits, and a smaller protopygidium, but lack anterior and mid-fixigenal spine pairs, while the other protaspides which lived in better oxygenated condition are larger, have three pairs of fixigenal spines and a larger protopygidium, and lack distinct anterior pits. Olenimorph form is retained by most, if not all, olenid holaspides, even by those which inhabited better oxygenated conditions, suggesting greater morphological plasticity in the protaspid period.
Distinct Taconic, Salinic, and Acadian deformation along the Iapetus suture zone, Newfoundland Appalachians
Authors: Zagorevski A , van Staal C R , McNicoll V J
Published: January 2008

Structural mapping in central Newfoundland has identified seven distinct phases of deformation (D1 to D7), the most significant of which are D1, D2, and D4. D1 involved the formation of a Middle and Late Ordovician south-southeast-directed thrust belt and concomitant development of mylonite and phyllonite. A Late Ordovician to Early Silurian D2 thrust and fold belt overprints D1 mylonitic deformation and is the most distinctive deformation event in the study area. Late Silurian to Devonian D4 is responsible for folds and north-northwest-directed dextral thrust and reverse faults that overprint D1 to D3 structures. D4 structures in central Newfoundland include the Exploits–Gander boundary. Subsequent deformation is generally of local significance only. The arc–back-arc complexes making up the various terranes in central Newfoundland are predominantly juxtaposed along D1 shear zones, which include the Red Indian Line. Our data indicate that terrane boundaries initiated during D1 may have protracted deformation histories spanning several deformation events. This has important implications for the interpretation of terrane boundaries in Newfoundland, as D1 terrane boundaries may be interpreted as D2 or D4 shear zones depending on the intensity of overprinting or reactivation. The deformation history proposed in this paper corresponds closely to that of established Appalachian orogenic cycles. D1 is correlated with the Ordovician Taconic orogeny and involved accretion of arc–back-arc complexes to the Laurentian margin. D2 and D4 are correlated with the Ordovician–Silurian Salinic and Silurian–Devonian Acadian orogenies, which involved the subsequent accretion of the Ganderia and Avalonia microcontinents to the Laurentian margin, respectively.
The relative influence of Laurentide and local ice sheets during the last glacial maximum in the eastern Chic-Chocs Range, northern Gaspé Peninsula, Quebec
Authors: Olejczyk Pawel , Gray James T
Published: January 2008

Geochemical signatures, erratic dispersal, and striae indicate glacial flows in the north-central Gaspé Peninsula exclusively from Appalachian sources, except for the coastal fringe. During the last glacial maximum (LGM), ice from the Monts McGerrigle flowed northward and northwestward over the summits of the eastern Chic-Chocs Range and the coastal plateau to the Gulf of St. Lawrence. Lesser flows also occurred to the north from Mont Albert and the western Chic-Chocs Range. Where intersecting striae were noted, the older flows are associated with a locally developed ice cap. The rare occurrences of striae and erratics, and morphometric and lithological characteristics of summit diamictons, imply limited basal erosion by both local and regional ice caps. This is postulated to result from early protection of rock surfaces by the initial buildup of thin, frozen-based ice in the eastern Chic-Chocs Range. A compact till mantle in the cols and on the coastal plateau and striae parallel to col directions indicate a downslope transition to wet-based ice. Occasional gneiss boulders above the marine limit between Cap-Chat and Sainte-Anne-des-Monts indicate a slight onlap of the Laurentide Ice Sheet (LIS), but the latter was excluded from the interior of the peninsula east of Cap-Chat. Whole-rock geochemistry from three granitoid erratics on Chic-Chocs summits and one in the York River basin indicates a local Devonian rather than a Precambrian Canadian Shield source. The absence of southward downwarping of synchronous postglacial marine limits across the Gaspé Peninsula corroborates this view for the LGM.
A revision of the stratigraphic nomenclature of the Cambrian–Ordovician strata of the Philipsburg tectonic slice, southern Quebec
Authors: Hersi O Salad , Nowlan G S , Lavoie D
Published: January 2008

The Philipsburg tectonic slice is bounded to the west by a northeast–southwest-trending thrust fault (Logan’s Line) and preserves 10 formations of Middle (?) to Late Cambrian (Milton, Rock River, and Strites Pond formations), Early Ordovician (Wallace Creek, Morgan Corner, Hastings Creek, and Naylor Ledge formations), and early Middle Ordovician (Luke Hill, Solomons Corner, and Corey formations) age. The strata were previously assigned to the Philipsburg Group. Early correlations between the Philipsburg succession and coeval strata of the St. Lawrence Platform were mainly based on sparse macrofauna and inferred stratigraphic position. Unconformities at the Cambrian–Ordovician and Early Ordovician – Middle Ordovician boundaries occurring in autochthonous St. Lawrence Platform and the allochthonous Philipsburg succession (Philipsburg tectonic slice) highlight new stratigraphic interpretations between the inner-shelf (St. Lawrence Platform) and the outer-shelf (Philipsburg) successions. The succession in the Philipsburg tectonic slice is divided into three new groups. The Middle (?) to Upper Cambrian Missisquoi Group (new) includes the Milton, Rock River, and Strites Pond formations. The upper boundary of the Missisquoi Group is defined by the upper unconformable contact between the Upper Cambrian Strites Pond Formation and overlying Lower Ordovician Wallace Creek Formation. The Missisquoi Group correlates with the Potsdam Group of the St. Lawrence Platform. The Lower Ordovician School House Hill Group (new) includes the Wallace Creek, Morgan Corner, Hastings Creek, and Naylor Ledge formations. The upper boundary of this group is marked by a regionally extensive unconformity at the top of the Naylor Ledge Formation and correlates with the younger Beekmantown-topping unconformity. The School House Hill Group is correlative with the lower to upper part of the Beekmantown Group (Theresa Formation and the Ogdensburg Member of the Beauharnois Formation) of the St. Lawrence Platform. The Middle Ordovician Fox Hill Group (new) consists of the Luke Hill, Solomons Corner, and Corey formations. This group correlates with the uppermost part of the Beekmantown Group (Huntingdon Member of the Beauharnois Formation and the Carillon Formation).
Conodont biostratigraphy of the latest Cambrian - Early Ordovician upper McKay Group, southeastern British Columbia
Authors: Pyle Leanne J , Barnes Christopher R , McAnally Lee McKenzie
Published: January 2008

The age of the upper McKay Group based on conodont biostratigraphy is latest Cambrian (Cordylodus proavus Zone) to late Early Ordovician (middle Floian; Oepikodus communis Zone). A collection of 12 940 conodont elements was recovered from 306 samples of upper McKay Group strata exposed in the Western Main Ranges of the southern Canadian Rocky Mountains, southeastern British Columbia. The conodont fauna is assigned to 53 species representing 30 genera. Twelve zones are recognized, two of which are cosmopolitan: Cordylodus proavus Zone and Iapetognathus Zone. Seven Midcontinent Realm zones, in ascending order, include Polycostatus falsioneotensis, Rossodus tenuis, Rossodus manitouensis, low diversity interval, Scolopodus subrex, and Acodus kechikaensis zones, and Tropodus sweeti Subzone (of the Oepikodus communis Zone). Three Atlantic Realm zones, in ascending order, include Cordylodus angulatus, Acodus deltatus, and Paroistodus proteus zones. The zonation for the upper McKay Group establishes correlation with the Survey Peak Formation and lower Outram Formation of the Bow Platform, and with the Kechika Formation and lower Skoki Formation of the Macdonald Platform and Kechika Trough in the northern Rocky Mountains. The McKay Group represents deposition during post-rift thermal subsidence of the margin, although its thickness, abrupt transition to black shale of the overlying Glenogle Formation, and intercalation of volcanogenic rocks imply a history of differential subsidence similar to that of the northern Cordillera, probably related to periodic extension.
Detrital zircon geochronology and provenance of Late Proterozoic and mid-Paleozoic successions outboard of the miogeocline, southeastern Canadian Cordillera
Authors: Lemieux Y , Thompson R I , Erdmer P , Simonetti A , Creaser R A
Published: January 2008

The Kootenay Arc has been interpreted as the western limit of autochthonous continental margin strata, west of which occur Paleozoic to Mesozoic rocks of uncertain paleogeographic origin. Recent mapping has demonstrated stratigraphic linkage between the Kootenay Arc strata and rocks farther west. A U–Pb study of detrital zircons using laser ablation – multicollector – inductively coupled plasma – mass spectrometry (LA–MC–ICP–MS) was undertaken in the upper succession of the Monashee complex mantling gneiss and in mid-Paleozoic strata of the Chase Formation exposed in the northern Kootenay Arc area and adjacent outboard strata. The predominance of >1.75 Ga zircon matches well with basement domains of the western buried North American craton and indicates that most of the grains were derived from a source of North American affinity. Zircon between 1.00 and 1.30 Ga demonstrates a Neoproterozoic source of possible “Grenville” affinity. Additional populations in the Chase Formation are mid-Paleozoic, Ediacaran, 800–1000 Ma, and 1400–1750 Ma. We interpret them to have been derived from exposed sources of Proterozoic continental crust and (or) proximal late Neoproterozoic and middle Paleozoic magmatic sources. The investigated Proterozoic and Paleozoic successions confirm sedimentologic and depositional relationships with the ancestral North American margin, and as such are interpreted to represent outboard extensions of the Cordilleran miogeoclinal succession.
The extent of ice on the continental shelf off Hudson Strait during Heinrich events 1-3
Authors: Rashid Harunur , Piper David JW
Published: January 2008

North Atlantic Heinrich events, which dispersed widespread sediment plumes and icebergs, originated principally from Hudson Strait ice streams of the Laurentide Ice Sheet. The dynamics and extent of these ice streams across the wide continental shelf seaward of Hudson Strait are not well understood. High-resolution airgun seismic reflection profiles from the outer shelf and slope show an acoustically incoherent, prograded unit at least 30 m thick. This unit has been sampled by piston cores and corresponds to a carbonate-rich diamicton unit interpreted as a glacigenic debris flow, locally overlain by carbonate-rich mud turbidites, dated as corresponding to Heinrich event 3 (H3). Younger glacigenic debris flow deposits are lacking. These data are compared with the seismic-stratigraphic record on the continental shelf, where a regional erosion surface at 10–200 m depth below the sea floor truncates Tertiary strata and is overlain by a 50 m thick diamicton (?subglacial till) sheet and is correlated with the H3 glacigenic debris flows. Above this unit, at least two distinct diamicton sheets terminate on the inner continental shelf. These data imply that grounded Laurentide ice crossed the continental shelf during H3, delivering large amounts of diamicton to the continental slope, but during the younger Heinrich events H1 and H2, no detectable record of diamicton was left on the outer shelf or slope. These findings account for observed differences between H3 and younger Heinrich events in the Labrador Sea.
The magic of sands— The 20th Bjerrum Lecture presented in Oslo, 25 November 2005This paper represents the written version of the 20th Bjerrum Lecture. While it has been edited for the present publication, it retains the general structure of the original lecture, which was intended for a general geotechnical audience. It deliberately points out some of the still-open questions concerning soil modelling. The Bjerrum Lecture is presented in Oslo in alternate years by the Norwegian Geotechnical Society with the support of the Bjerrum Memorial Fund (Laurits Bjerrums Minnefond).
Authors: Muir Wood David
Published: January 2008

Following the discovery of sinkholes in the W.A.C. Bennett Dam, British Columbia, in 1996, investigations showed that there had apparently been movement of fine material out of the core of the dam. To be able to predict the mechanical consequences of such movement of material, a class of soil model that is able to accommodate changes in both density and grading of the soil is required. An outline of features of the Severn–Trent sand model — which incorporates effects of density variation — is presented and a suggestion is made for ways this model might be extended to include effects of changing particle size distribution.
Seismic record analysis of the Liyutan earth dam
Authors: Hwang Jin-Hung , Wu Chia-Pin , Wang Sheng-Chin
Published: January 2008

In this paper the authors present an analysis of the seismic records of the Liyutan dam, which is a zoned compacted earth dam. It is 96 m in height, and it suffered some minor cracks and settlement during the 1999 Chi-Chi earthquake. A large amount of seismic motion has been recorded for 42 past earthquake events. These records were used to analyze the vibration characteristics of the dam. The fundamental frequency and nonlinear amplification of the peak ground motion of the dam body have been clearly identified. Based on the fundamental frequency identified from the small earthquake data, the seismic motion of the dam during the Chi-Chi earthquake could be well simulated by an equivalent linear dynamic procedure. An empirical decomposition method was used to decompose the Chi-Chi earthquake motion histories, from the top and the bottom of the dam, into several orthogonal and complete intrinsic mode functions (IMFs). These IMFs show that the low frequency parts of the seismic motion at the top and bottom of the dam are nearly the same, however, the high frequency parts are significantly amplified when the seismic motion propagates from the bottom to the top of the dam.
Évaluation des ouvrages hydrauliques de génie civil
Authors: Serre Damien , Peyras Laurent , Curt Corinne , Boissier Daniel , Diab Youssef
Published: January 2008

This paper reviews Cemagref (Centre national du machinisme agricole, du génie rural, des eaux et des forêts) research on assessment of hydraulic works, especially on their performance and safety. A generic functional model has been developed, using reliability methods, to represent the various mecanisms acting on different hydraulic works (gravity and embankment dams, fluvial dikes, etc.). Collecting and analyzing data on the failure of these works allowed us to define structural indicators and the rules for their assessment. Performance indicators for hydraulic works were created through multicriteria aggregation methods; various results were thus obtained. A database of knowledge relating to mechanisms and histories of dam ageing has been produced and constitutes a useful aid for consulting civil engineers. Methods and tools have been developed to assess the performance of fluvial dikes and to assist managers in planning maintenance operations. Similar research is under way on embankment dams and will provide a diagnosis tool for hydraulic works in operation.
Mating system estimates and effective population numbers for an isolated noble fir (Abiesprocera) clonal seed orchard in Denmark
Authors: Siegismund Hans R. , Kjær Erik D. , Nielsen Ulrik Bräuner
Published: January 2008

The mating system of a seed orchard of noble fir (Abiesprocera Rehd.) in Denmark was analyzed, with variation being found at two unlinked isozyme loci. Comparison of allele frequencies in the pollen pool fertilizing the upper and the lower parts of the trees showed a homogeneous distribution. There was no difference in the outcrossing rates estimated for cones harvested at the top and the lowermost branches carrying cones. Both were slightly greater than 1, as was the combined estimate that did not differ significantly from 1. The clones present in the seed orchard are outcrossing, and the allele frequencies found in the pollen pool agree with the frequencies found in the clones of the seed orchard on average. However, the allele frequencies varied significantly between the 20 families, suggesting that the pollen pool has been variable within the seed orchard. The inbreeding and variance effective population numbers were estimated by assuming that the differences in flowering reflected variation in gamete contribution from the clones to the offspring. The inbreeding effective population number was found to be 65% of the total number of clones. The variance effective population number was 121% of the number of clones when it was assumed that a large number of offspring were harvested from every clone.
A model of hyperparasite regulation of the gall rust–lodgepole pine pathosystem
Authors: Kamp Bart J. Van Der , Blenis Peter V.
Published: January 2008

Endocronartiumharknessii (J.P. Moore) Hirat. populations never approach the level where all susceptible Pinuscontorta Dougl. ex Loud. var. latifolia Engelm. tissue is infected, even in years when environmental conditions are favourable for infection. A simple simulation model was developed to determine whether a hyperparasite could regulate the rust population and maintain it at an equilibrium level far below host saturation. The model assumed that galls begin sporulating and first become susceptible to parasitism 2 years after formation and requires specification of infection rates for the rust and the hyperparasite, mortality rates for normal and parasitized galls, and the degree to which aeciospore production is reduced following hyperparasite infection. Analysis of the model showed that the hyperparasite could regulate the rust population, producing a stable equilibrium, but only if the various rates were such that healthy galls, in their lifetime, produced enough aeciospores to give rise to more than one new gall, while galls that were parasitized during the first year of aeciospore production produced, in their lifetime, fewer than one new gall. The model of hyperparasite regulation provides one possible explanation of the dynamics of the gall rust pathosystem. It shows that control measures such as sanitation and breeding for resistance may reduce the effectiveness of the hyperparasite in regulating the system and, thus, may fail to achieve the anticipated goals.
Growth and form of western larch stecklings: plagiotropism and reiteration
Authors: Edson John L. , Wenny David L. , Fins Lauren , Roberts Lorin W.
Published: January 2008

Western larch (Larixoccidentalis Nutt.) in the interior northwestern United States produces small and infrequent cone crops resulting in recurrent seed shortages throughout much of its range. Vegetatively propagated planting stock could potentially alleviate shortages of seedlings for artificial regeneration. In a greenhouse study to evaluate suitability of rooted cuttings for forestry, morphology and growth of container-grown stecklings from 1- and 3-year-old ortets were compared with seedlings for up to 6 years after rooting. Newly rooted stecklings produced an average 50% orthotropic, 32% plagiotropic, and 18% suppressed leaders. One-year-old steckling leaders elongated 46% as long as 1-year-old orthotropic steckling leaders after fertilization with 20:20:20 N–P–K at 120 ppm N (p = 0.0001). In subsequent years, orthotropic stecklings elongated more than seedlings. Plagiotropic leaders (average deflection of 24°) developed upright form within 2 years. Competing axillary shoots delayed development of dominant leaders for up to 3 years. Vestiges of atypical habit included small basal stem crooks and sparse branching. Although staking and pruning promoted excurrent habit, poor quality of container-grown stecklings can limit indoor nursery production. Effects of ortet and environment on quality should be examined before stecklings are field tested for use in reforestation.
Effects of mechanical strip thinning of aspen on small mammals and breeding birds in northern Minnesota, U.S.A.
Authors: Christian Donald P. , Reuvers-House Marlys , Hanowski Joann M. , Niemi Gerald J. , Blake John G. , Berguson William E.
Published: January 2008

Abundance and species composition of small mammals and breeding birds were studied on mechanically strip-thinned aspen stands and comparable reference stands in northern Minnesota. Strip-thinned stands included sapling-sized stands thinned 1 or 2 years before the study and pole-sized stands thinned 7–11 years previously. Fewer individual birds were observed on sapling-sized thinned than reference stands, reflecting primarily decreases in abundances of bird species that select midsuccessional deciduous forests; several of these species are long-distance migrants. Bird abundance and community composition on thinned and reference pole-sized stands were similar, differing most notably in the presence of Canada Warbler (Wilsoniacanadensis (L.)) and Downy Woodpecker (Picoidespubescens (L.)) in thinned but not reference stands. Significantly more individual small mammals were captured on thinned than reference stands, and most other measures of abundance indicated positive numerical responses of small mammals to strip thinning. Mechanical strip thinning of aspen shows promise for enhancing aspen supply by allowing trees to grow more rapidly to harvestable size. Our results suggest that use of this practice has no negative effects on small mammals and relatively short-lived negative effects on forest songbirds at the stand level.
Varying levels of information and the embedding problem in contingent valuation: the case of Canadian wilderness
Authors: Macdonald Heather , McKenney Daniel
Published: January 2008

This study examines the effect of providing varying amounts of information and embedding to contingent valuation respondents in the context of wilderness reservation. Contingent valuation is a technique developed to assess the monetary value of nonmarket goods by asking survey respondents how much they would be willing to pay (or accept) for an increase (or decrease) in the level of provision of such goods. Embedding refers to obtaining willingness-to-pay measures for a good when it is valued as part of a larger good. When subjects were provided with more complete information to make evaluations, their willingness-to-pay responses were reasonably consistent across levels of embedding. In contrast, when little background information was provided, willingness-to-pay amounts were inconsistent and showed significantly more variability and greater signs of embedding. In addition, low-information subjects volunteered more protest zeros and reported feeling slightly less confident of their responses. Perhaps the most interesting finding was the difference in mean valuations depending on how much background information subjects received. This issue of information provision can be a problematic challenge for contingent-valuation practitioners.
Mortality of hybrid triploid aspen in Wisconsin and Upper Michigan
Authors: Enebak S.A. , Wyckoff G.W. , Li B. , Ostry M.E.
Published: January 2008

In eight field trials in Upper Michigan and Wisconsin, mortality of hybrid triploid aspen (Populustremuloides Michx. × Populustremula L.) was 93% by age 25, which was nearly twice that of native diploid and triploid aspen. Symptoms of decline observed on individuals of the hybrid triploid families included branch dieback, thinning crowns, and eventually tree death. The fungus Lahmiakunzei (Koerb.) (syn. Parkerellapopuli (Funk)) was found associated with a number of families from one specific hybrid triploid cross (T-1-58 × Ta-10). Symptoms of rough, black bark developed on 3% of the trees from this particular cross 10 years after planting and increased to 92% at age 25. Neighboring hybrid diploids of P. tremuloides × P. tremula and native triploids and diploids neither exhibited rough bark symptoms associated with L. kunzei nor showed symptoms of decline like those observed on the hybrid triploids. Mortality of native triploids and diploids in these trials was 41% and 58%, respectively, which was primarily caused by hypoxylon canker. Thinning crowns caused by branch dieback and tree mortality without the presence of L. kunzei has been common on the male tetraploid parent (Ta-10) in clone banks and seed orchards in Minnesota and Wisconsin. This parent was collected from an oceanic region near Ekebo, Sweden, and it, along with its hybrid progeny, appear to be poorly adapted to the climate of Upper Michigan, Minnesota, and Wisconsin, resulting in the high mortality of the hybrid triploids in these trials. The origin of the fungus L. kunzei and the nature of its specificity to T-1-58 × Ta-10 hybrid triploid cross are unknown.
Development of monoclonal-antibody-based immunobinding assays to detect growth of Gliocladiumroseum, a potential bioprotectant on unseasoned lumber
Authors: McAfee B.J. , Chan M. , Banerjee S. , Brown D.L.
Published: January 2008

Gliocladiumroseum Bain 321U is a potential bioprotectant against sapwood stains for unseasoned western hemlock (Tsugaheterophylla (Raf.) Sarg.) and amabilis fir (Abiesamabilis (Dougl. ex Loud.) Dougl. ex J. Forbes) lumber. An immunostaining method was developed to monitor spore germination and growth of G. roseum 321U on lumber during microcosm and field investigations. Spores, mycelium, or fungal extracts were immobilized on polyethersulfone or polyvinylidene difluoride membranes. The membranes were then probed with the G. roseum monoclonal antibody (6A5), and the fungus was detected either by using a chromogenic substrate or by enhanced chemiluminescence.
Variation in overstory biomass among glacial landforms and ecological land units in northwestern Lower Michigan
Authors: Host George E. , Pregitzer Kurt S. , Ramm Carl W. , Lusch David P. , Cleland David T.
Published: January 2008

Variation in overstory biomass and mean annual biomass increment (MABI) of upland forest stands was studied at two spatial scales: glacial landforms (1: 250 000–1: 000 000) and ecological land units (1: 10 000–1: 80 000). Ecological land units were defined based on combinations of ground-flora vegetation, soil, and physiography. Biomass estimates were based on allometric regression equations developed in the Lake States area. Analyses of covariance were used to study the patterns of total biomass and biomass increment among glacial landforms and among ecological land units; stand age was used as the covariate. Overstory biomass ranged from 105 t/ha (MABI = 1.5 t ha−1 year−1) on glacial outwash landforms to 208 t/ha (MABI = 3.2 t ha−1 year−1) on morainal landforms; 37% of the total variation in biomass was accounted for by landform. Analysis at the ecological land unit scale accounted for a higher proportion of variation, approximately 60% of the total. Overstory biomass among ecological land units ranged from 85 t/ha (MABI = 1.3 t ha−1 year−1) for oak-dominated forests occurring on xeric sandy outwash sediments to almost 250 t/ha (MABI = 3.6 t ha−1 year−1) for sugar maple–red oak forests occurring in mesic morainal positions. Variation in biomass appeared to be strongly related to differences in species composition and variation in soil moisture availability, as evidenced by differences in soil texture and the presence or absence of deep-lying textural bands. Since ground-flora composition often reflects variation in soil properties, we examined the relationship between ground-flora composition and biomass increment. Detrended correspondence analysis was used to ordinate stands along a floristic gradient. Regression of stand ordination scores against MABI was significant (r2 = 0.65), indicating a relatively strong association between ground-flora composition and productivity. One advantage of understanding spatial variation in site productivity is that ecological land units can be readily mapped, whereas traditional estimates of site potential, such as site index, are point specific.
Problèmes d'inférence statistique reliés à la transformation logarithmique en régression
Authors: Ung Chhun-Huor , Végiard Sylvain
Published: January 2008

In regression calculations, a return to the original scale after logarithmic transformation constitutes a bias. This paper analyses three methods of bias correction for point estimation of the mean and four methods of bias correction for the interval estimation of the mean; some details about the interval prediction of a new observation are given. The appropriateness of using the methods reviewed in various circumstances is also discussed.
Populustrichocarpa × Populusdeltoides hybrids for short rotation culture: variation patterns and 4-year field performance
Authors: Stettler Reinhard F. , Fenn Ruth C. , Heilman Paul E. , Stanton Brian J.
Published: January 2008

Studies were conducted on the comparative growth and morphology of Populustrichocarpa (T), P. deltoides (D), F1 hybrids (T×D), F2 hybrids (TD × TD), and B1 hybrids (T × TD, TD × T) at one nursery and two plantation sites in western Washington and Oregon. First coppice resprouts in the nursery showed intermediacy of the F1 and F2 between parentals in four of five morphological leaf traits measured, and intermediacy of B1 values between F1 and T in three. Amounts of variation generally conformed to the model of F2 > B1 > F1. The percent significant trait correlations were 11.6 for the F1, 8.7 for the B1, and zero for the F2. No simply inherited traits were identified. Growth in the first and successive coppices in the nursery was significantly greater in the F1 than in the B1 and F2 generations. The same trend was observed in two field tests at Pack Forest, Washington and Westport, Oregon in which 691 and 381 clones from 60 and 42 families, respectively, gave a rank order in 4-year volume growth of F1 > B1 > T > F2 > D. Several F1 families and clones showed high rank consistency between years and locations. The results confirm earlier studies and are discussed in relation to the mechanisms that underlie T × D hybrid superiority.
Foliar nutrient status in relation to sugar maple dieback and decline in the Quebec Appalachians
Authors: Bernier B. , Brazeau M.
Published: January 2008

Forty-five mature sugar maple (Acersaccharum Marsh.) stands growing on soils associated with a wide range of geological formations in the Quebec Appalachians were sampled in both early to mid-July and mid- to late August 1985. The average level of forest decline, as indicated by foliage density, was 15%, ranging from 1 to 69%. The foliar concentrations of N, P, Ca, Mg, Mn, Fe, Zn, and B in July were generally adequate while K concentrations were <0.55% in nine sites (20% of the sites). Mean K concentrations in July and August were 0.68% and 0.62%, respectively, with only one value in excess of 0.90% in July, which is below most K concentrations reported in the literature for sugar maple. Results are presented for two distinct regions within the study area. Most stands with foliar K levels less than 0.55% in July exhibited high levels of decline (15–69%) while the majority of stands with K in excess of this concentration showed low levels of decline. These data suggest that K deficiency (sometimes accompanied by an acute P deficiency) influences the integrity of forest ecosystems and may play a significant role in the decline of the deciduous forest in the Quebec Appalachians.
AdS/QCD and the pion mass
Authors: Hirayama Takayuki
Published: January 2008

To realize massive pions, we study variations of the holographic model of massless QCD using the [Formula: see text] brane configuration proposed by Sakai and Sugimoto. We propose deformations which break the chiral symmetry explicitly and compute the mass of the pions and vector mesons. The observed value of the pion mass can be obtained. We also argue a chiral perturbation corresponding to our deformation.
BLACK HOLE PRODUCTION AT THE LARGE HADRON COLLIDER
Authors: GINGRICH DOUGLAS M.
Published: January 2008

Black hole production at the Large Hadron Collider (LHC) is an interesting consequence of TeV-scale gravity models. The predicted values, or lower limits, for the fundamental Planck scale and number of extra dimensions will depend directly on the accuracy of the black hole production cross-section. We give a range of lower limits on the fundamental Planck scale that could be obtained at LHC energies. In addition, we examine the effects of parton electric charge on black hole production using the trapped-surface approach of general relativity. Accounting for electric charge of the partons could reduce the black hole cross-section by one to four orders of magnitude at the LHC.
THE ACCELERATING EXPANSION OF THE UNIVERSE AND TORSION ENERGY
Authors: WANAS M. I.
Published: January 2008

In the present work, it is shown that the problem of the accelerating expansion of the Universe can be directly solved by applying Einstein geometrization philosophy in a wider geometry. The geometric structure used to fulfil the aim of the work is a version of Absolute Parallelism geometry in which curvature and torsion are simultaneously non vanishing objects. It is shown that, while the energy corresponding to the curvature of space- time gives rise to an attractive force, the energy corresponding to the torsion indicates the presence of a repulsive force. A fine tuning parameter can be adjusted to give the observed phenomena.
Overview of astroparticle physics and dark matter searches
Authors: Palanque-Delabrouille Nathalie
Published: January 2008

We present a general overview of recent results in the searches for dark matter and dark energy. We discuss the observation of the collision between two clusters of galaxies, and the impact this has on the relevance of dark matter. We then present the final results from microlensing experiments, which aimed at detecting dark baryonic objects in the halo of our galaxy, and the status of direct searches for WIMPs. We present the evidence for dark energy which initially comes from experiments dedicated to the study of distant type Ia supernovae. The measure of the baryon acoustic oscillation, an independent probe of the evolution of our universe that has recently brought interesting constraints, is finally described.