bluuebunny/crossref_metadata_2025 huggingface dataset:
Caractéristiques des conditions benthiques existant dans la partie amont du fjord du Saguenay (Québec, Canada)
Authors: Moreau Ann-Laure , Locat Jacques , Long Bernard , Ouellet Yvon
Published: July 2007

In 1996, following torrential rains, a layer of clean sediments was deposited in the upstream part of the Saguenay Fjord. This layer acted as a damping layer between contaminated sediments and the Saguenay waters. It is important to collect information on the water–sediments interface, which is the site of exchanges between the sediments and the waters. Three oceanographical campaigns have allowed us to obtain the data on the velocity of the benthic currents and the properties of the surface sediments. The velocities have been obtained by means of two current meters located at 3 m from the bottom and by means of registered videos. These two types of measurements have given comparable results. The main information collected on the sediments were their water content, grain size, density, and the presence of benthic fauna. The distribution of the main biogenic structure, the tubes of polychetes, is related to the depth of the site and to the grain size of the sediments. For the surface layer, large variations of the water content were obtained during the field measurements. Tests with an axial tomodensitometer have revealed a large variation in the density of the sediments in the top 2.5 cm.Key words: Saguenay Fjord, benthic sediments, axial tomodensitometer.[Journal translation]
In situ shear wave velocity from multichannel analysis of surface waves (MASW) tests at eight Norwegian research sites
Authors: Long Michael , Donohue Shane
Published: July 2007

The multichannel analysis of surface waves (MASW) technique, which is used to determine shear wave velocity (Vs) and hence small strain stiffness (Gmax), has recently generated considerable interest in the geophysics community. This is because of the ease of carrying out the test and analysis of the data. The objective of this work was to assess the repeatability, accuracy, and reliability of MASW surface wave measurements for use in engineering studies. Tests were carried out at eight well-characterized Norwegian clay, silt, and sand research sites where Vs had already been assessed using independent means. As well as being easy and quick to use, the MASW technique gave consistent and repeatable results, and the MASW Vs profiles for the clay sites were similar to those obtained from other techniques. Reasonable results were also obtained for the silt and sand sites, with the best result being obtained for the finer silt. This work also confirms that MASW Vs clay profiles are comparable to those obtained by correlation with cone penetration test (CPT) data. For these sites there also seems to be a good correlation between normalized small strain shear modulus and in situ void ratio or water content, and the data fit well with published correlations for clays.Key words: soft clays, silts, sands, small strain stiffness, shear wave velocity.
Postfire survival in Douglas-fir and lodgepole pine: comparing the effects of crown and bole damage
Authors: Peterson David L. , Arbaugh Michael J.
Published: July 2007

Survival patterns after late summer wildfires were evaluated for Douglas-fir and lodgepole pine in the northern Rocky Mountains. Crown scorch was the most important variable for predicting postfire survival and variables representing bole damage improved the significance of logistic regression models for both species. Crown scorch and basal scorch were the best combination of variables for predicting survival in lodgepole pine. Crown scorch and insect damage were the best combination of variables for predicting survival in Douglas-fir. Postfire survival of lodgepole pine, which has relatively thin bark, was more sensitive than Douglas-fir to variables that quantified bole damage.
Cone clusters in jack pine
Authors: Rudolph Thomas D. , Wheeler Nicholas C. , Dhir Narinder K.
Published: July 2007

Regularly repeated seed cone clustering on two jack pine (Pinusbanksiana Lamb.) trees, one in Alberta, Canada, and the other in Wisconsin, U.S.A., is described. The clusters on the Alberta tree apparently result from the replacement of dwarf shoots by ovulate cones; those on the Wisconsin tree apparently result from replacement of staminate cones by ovulate cones. The low frequency of cone clustering in open-pollinated progenies of the two trees suggests that the clustering trait may be controlled by a single recessive gene.
Damage to northern hardwoods from thinning using whole-tree harvesting technology
Authors: Ostrofsky W. D. , Seymour R. S. , Lemin Jr. R. C.
Published: July 2007

A mechanized whole-tree harvesting system, which has recently found widespread use in northern New England, was evaluated for its impact on residual crop trees in two northern hardwood stands in western Maine. Stand type, skid trail spacing, and whether or not skid trails were designated prior to harvesting significantly influenced stand damage levels. A higher mean percentage of residual trees was injured in a Betulapapyrifera Marsh, stand (49%) than in similar treatments in a Fagusgrandifolia Ehrh. – Quercusrubra L. stand (32%). A spacing of 20 m between predesignated trails resulted in less damage (22%) to the remaining trees than a spacing of 40 m (53%), but with many more potential crop trees cut for trails. At both sites, highest total damage was found in treatments where no skid trails were predesignated, with 82 and 43% of the crop trees damaged or removed in the B. papyrifera stand and the Fagus–Quercus stand, respectively. Models were developed to predict the effects of thinning systems, tree size, species, dbh, stand basal area, and distance from tree to skid trail on the probability of being damaged. High damage levels indicate that such harvesting systems are unsuitable for some sites and require careful planning and layout on all sites.
Landscape variation in nitrogen mineralization and nitrification
Authors: Zak Donald R. , Pregitzer Kurt S. , Host George E.
Published: July 2007

Potential nitrogen mineralization and nitrification were studied in three upland forest ecosystems to develop an understanding of nitrogen turnover on a landscape basis. The northern Michigan forests studied were an oak ecosystem primarily associated with glacial outwash features and two sugar maple ecosystems that occurred on morainal landforms but differed in the diversity and abundance of ground flora species. Four randomly chosen stands separated by at least 6 km were sampled within each of the three ecosystems. Potential net nitrogen mineralization and nitrification were determined by an aerobic laboratory incubation. Litter was collected from all ecosystems during autumn. Litter production, nitrogen returned to the forest floor, and net mineralization differed by a factor of two between the oak and sugar maple ecosystems. The species-rich sugar maple ecosystems exhibited a fourfold increase in potential nitrification compared with the species-poor sugar maple ecosystem. Nitrification was virtually absent in the oak ecosystem. The distribution of ecosystems could be used to predict differences in potential mineralization and nitrification. Areas susceptible to nitrate loss following intensive forest management practices may be related to the occurrence of plant associations. In this upland landscape, high nitrification potentials appear to be confined to species-rich sugar maple forests.
Specific leaf area and leaf area index distribution in a young Douglas-fir plantation
Authors: Borghetti M. , Vendramin G. G. , Giannini R.
Published: July 2007

The spatial distribution of specific leaf area and leaf area index of needles in different age classes has been investigated in a young and unthinned Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) plantation in Central Italy through the destructive analysis of 12 trees sampled in four diameter size classes. Specific leaf area decreased with leaf age and from crown base to apex. A clear interaction between the effects of age and position on specific leaf area was demonstrated. For the whole canopy the vertical distribution of leaf area was well fitted by a normal curve equation, which explained 97% of the variation. The midpoint of the leaf area distribution, estimated as a parameter of the normal curve, was found to be 1.2 m below the mean canopy depth. The standard deviation of leaf area with respect to height was 16.4%. The midpoint of leaf area distribution decreased as leaf age increased and increased as diameter size class increased. Strong and significant linear relationships were found between leaf biomass, leaf area, sapwood area, and diameter at breast height.
Insects associated with the transmission of Verticicladiellaprocera
Authors: Lewis Kathy J. , Alexander S. A.
Published: July 2007

Insects in the families Scolytidae and Curculionidae were studied as potential vectors of the fungus Verticicladiellaprocera Kendrick. Weevils (Hylobiuspales Herbst and Pissodes sp.) and bark beetles (Pityogenes sp., Orthotomicus sp., Xyleborus sp., and Hylastes sp.) contaminated with V. procera were trapped in seven and three Pinusstrobus L. Christmas tree plantations, respectively, including plantations where V. procera had not been found. Percent of trapped weevils and bark beetles carrying V. procera was 64.2 and 0.76, respectively. Bolts (92%) became colonized by V. procera following visitation in the field by contaminated insects. Under controlled conditions, transmission of the fungus from contaminated weevils placed in cages to previously uncolonized bolts occurred three of seven times. Bark beetles transmited V. procera to eastern white pine bolts less frequently than weevils. Transmission of the fungus to seedlings did not occur. These studies suggest that insect vectors are important for spread of V. procera, and that weevils are probably the primary vectors.
Logging and soil disturbance in southeast British Columbia
Authors: Krag R. , Higginbotham K. , Rothwell R.
Published: July 2007

The purpose of this study was to document and to analyze extent, type, and degree of soil disturbance on ground-skidded and cable-yarded cutovers. The primary hypothesis was that ground skidding on steep, high elevation sites generates more soil disturbance than cable yarding. Thirty-one cutovers were surveyed in the Nelson Forest Region: 25 logged by ground skidding and 6 by cable yarding. Three replications were obtained for each season – slope class on ground-skidded sites. Cable-logged areas were also replicated three times, but only for season. Elevations of the cutovers ranged from 910 to 1970 m with an average of 1360 m. Slope steepness on cutovers ranged from 5 to 74%. Soil disturbance was significantly greater on ground-skidded than on cable-yarded cutovers, averaging 40–45% vs. 22–30%, respectively, regardless of season. Differences in soil disturbance between logging methods by season were small and not significant. Average soil disturbances for summer cable yarding and ground skidding were 30 and 45%, respectively, compared with 22 and 40% for winter operations. Analysis of soil disturbance by source revealed skidroads as the major cause of disturbance on ground-skidded cutovers, regardless of season. The primary source of disturbance on cable-yarded areas was yarding in the summer and haul roads in the winter. Ground skidding also caused more deep to very deep disturbance, averaging 30% in winter and 35% in summer compared with 18 and 14% on cable-yarded sites. For both methods deep and very deep disturbance were most common accounting for 75–80% of total disturbance. Extent of soil disturbance and slope steepness were not significantly related. The high variability in soil disturbance noted in this study was similar to other surveys. Most studies have attempted to associate such variation with major environmental factors but with little success. To fully explain soil disturbance, operational factors such as planning and layout of logging must be considered.
Structural conditions of mesophyll cells of Pinusponderosa var. scopulorum after SO2 fumigation
Authors: Kärenlampi Lauri , Houpis James L. J.
Published: July 2007

Ultracytopathological observations on Pinusponderosa var. scopulorum needles after long-term fumigation with SO2 showed several symptoms. These included lack of starch grains, vacuoles with darkly stained deposits, occurrence of large droplets of lipid-like material, and rounded shape of the chloroplasts (also associated with swelling of thylakoids).
Coniferous afforestation leads to soil acidification in central Ontario
Authors: Brand David G. , Kehoe Paul , Connors Maureen
Published: July 2007

The soil pH under 20 coniferous plantations on abandoned farmland at the Petawawa National Forestry Institute was remeasured after 46 years and showed a significant decrease. Soils under white spruce (Piceaglauca (Moench) Voss) showed the greatest degree of acidification, with the average pH in 13 plantations decreasing by 1.28.
Gas exchange characteristics of bald cypress (Taxodiumdistichum L.): evaluation of responses to leaf aging, flooding, and salinity
Authors: Pezeshki S. R. , DeLaune R. D. , Patrick Jr. W. H.
Published: July 2007

Bald cypress (Taxodiumdistichum L.) seedlings were subjected to flooding with saline water containing 0 to 8 parts per thousand (137 mequiv. L−1 NaCl) under controlled environment conditions. Imposition of flooding and salinity stresses was designed to simulate the increase in submergence and salinity level which Louisiana's extensive cypress forests are currently experiencing as a result of rapid subsidence. The effect of flooding and salt water intrusion on subsequent stomatal behaviour and net photosynthesis for leaves developed before and after salt exposure were measured. Flooding and salinity resulted in a substantial decrease in stomatal conductance and net photosynthesis in both young and old leaves. Leaf aging did not significantly affect stomatal conductance and photosynthesis. Only plants flooded with freshwater and those flooded with low salinity concentration produced new leaves with improved stomatal conductance and net photosynthesis, which suggests some stomatal and photosynthetic acclimation to flooding and low salinity for bald cypress. Increase in salinity, however, caused more extensive impact and greater reductions of stomatal conductance and net photosynthesis in both leaf ages.
Comparison of the photosynthetic responses to temperature and light of Betulamaximowicziana and Betulaplatyphylla var. japonica
Authors: Koike Takayoshi , Sakagami Yukio
Published: July 2007

not available
The stand dynamics of lodgepole pine
Authors: Tait D. E. , Cieszewski C. J. , Bella I. E.
Published: July 2007

A general stand model is fitted to a set of permanent sample plot data for lodgepole pine in Alberta. The model represents a site-specific, variable-density stand model for volume growth and mortality of lodgepole pine. The structure of the model provides a general framework for examining volume growth and mortality in lodgepole pine. The model's performance is compared with the Alberta Forest Service yield tables and with the results of an experimental thinning study.
Comparison of constant and variable allometric ratios for predicting foliar biomass of various tree genera
Authors: Geron Chris D. , Ruark Gregory A.
Published: July 2007

An equation that incorporates a variable allometric ratio (VAR) was compared with the traditional "power function" for estimation of foliage weight for six tree species. The equations were fitted using diameter at breast height (DBH) and diameter at the base of the live crown as predictors. When DBH was used as the independent variable, the VAR explained statistically significant additional variation in three of the six species examined, and in most cases reduced bias. Residual analysis indicated no need for a more complex mathematical expression than the linear VAR. However, the flexibility of the VAR was not necessary when diameter at the base of the live crown was used as the predictor variable. The use of combined variable predictors (DBH × total height) and multiple regression on DBH and total height was also examined.
Sodium fluoride induced metabolic changes in jack pine seedlings. I. Effect on gas exchange, water content, and carbohydrates
Authors: Zwiazek J. J. , Shay Jennifer M.
Published: July 2007

Dark respiration, photosynthesis, water content, and carbohydrate pools were examined in jack pine (Pinusbanksiana Lamb.) seedlings treated for 1–7 days with sodium fluoride. Compared with those of controls, both respiratory rates and respiratory quotient decreased in plants treated for 1 day. Photosynthetic rates declined in plants exposed to fluoride for 1, 2, and 4 days. Recovery was observed in seedlings treated for 7 days. A decrease in water content was noted as early as 1 day after the exposure of plants to fluoride, and seedlings treated for longer periods continued to contain less water than control plants. The following effects of sodium fluoride treatment on carbohydrates were observed. Firstly, inositol increased in plants after 1 day, glucose increased after 1 and 2 days, and starch significantly declined in plants treated for 1 day. Sucrose was also initially present in lower amounts in fluoride-treated seedlings. Plants treated for 7 days contained levels of sucrose similar to those of controls. The possibility that water stress may be partly responsible for some of the metabolic changes is discussed.
Sodium fluoride induced metabolic changes in jack pine seedlings. II. Effect on growth, acid phosphatase, cytokinins, and pools of soluble proteins, amino acids, and organic acids
Authors: Zwiazek J. J. , Shay Jennifer M.
Published: July 2007

The effects of sodium fluoride on growth, cytokinin activity, acid phosphatase activity, and levels of soluble proteins, free amino acids, and organic acids in jack pine (Pinusbanksiana Lamb.) seedlings were studied. Fresh and dry weights of seedlings were already reduced after 24 h of sodium fluoride treatment. No significant change in cytokinin levels was found in seedlings treated with 1 mM sodium fluoride. A higher (10 mM) concentration resulted in some decrease in cytokinin activity, which was insufficient, however, to account for the complete growth inhibition of seedlings. Marked reduction in cytokinin(s) with similar chromatographic behaviour to that of isopentenyl adenine and isopentenyl adenosine was observed in plants subjected to the 10-mM sodium fluoride treatment. Activity of acid phosphatase extracted from seedlings was drastically reduced by sodium fluoride invitro. When the enzyme was isolated from fluoride-treated plants, its activity was also lower but the inhibition was less pronounced. Levels of both organic and amino acids were affected by fluoride treatments. Depending on the level of fluoride treatment, the amount of soluble proteins decreased or showed no significant change. The implications of the observed changes are discussed.
Population structure and genie diversity in tamarack, Larixlaricina (Du Roi) K. Koch
Authors: Cheliak W. M. , Wang J. , Pitel J. A.
Published: July 2007

Levels of electrophoretically detectable variation at 19 loci were estimated in 36 populations representing the natural range of Larixlaricina (Du Roi) K. Koch. Results of this survey indicated that the species has levels of genic variation comparable with those of other species of woody perennials with extensive transcontinental ranges. There was no evidence of significant departures from Hardy–Weinberg expectation. However, on average, populations of this species were more differentiated and more genetically divergent from one another compared with many randomly mating tree species. A discriminant analysis of the genotypic structure of the populations analyzed indicated a general east versus west pattern, with populations in the Great Lakes basin being further differentiated. Present-day population distribution, population density, and reinvasion routes after the last glaciation could account for the observed patterns of genic variation.
Basic wood properties of European larch from fast-growth plantations in eastern Canada
Authors: Keith C. T. , Chauret G.
Published: July 2007

A number of basic wood quality characteristics were evaluated in 10 European larch (Larixdecidua Mill.) trees, 5 from each of two rapidly growing plantations in eastern Ontario (approximately 30 years old) and western Quebec (approximately 25 years old). Characteristics evaluated included growth rate, relative density, fibre dimensions, longitudinal shrinkage, alcohol–benzene and water-soluble extractives, and Klason lignin. Radial and longitudinal patterns of variation in wood characteristics were examined and particular attention was given to the distribution of juvenile wood within the stems. Extractive contents were more closely related to the extent of heartwood and sapwood in the stems than to differences between juvenile and mature wood. Relative density was generally lower at the centre of the stem than in the mature outer wood, but the change was usually gradual, with no distinct boundary between juvenile and mature wood zones. The most useful characteristic for delimiting the juvenile wood zone appeared to be longitudinal shrinkage. On this basis, the transition from juvenile to mature wood occurs at about 15 rings out from the pith at breast height. Ranking of individual trees for wood density was judged to be reliable at about 7 years of age at this height level.
Fire behavior, fuel consumption, and forest-floor changes following prescribed understory fires in Sierra Nevada mixed conifer forests
Authors: Kauffman J. Boone , Martin R. E.
Published: July 2007

We quantified fire behavior, fuel consumption, and forest-floor responses to understory fires prescribed to cover a wide range and variable combination of fuel loadings, fuel moisture levels, and weather conditions in Sierra Nevada mixed conifer forests. At each of three locations, five burns were conducted under each of four different prescriptions (n = 60). Fuel loads ranged from 75–102 Mg/ha on an open site of low productivity to 125–177 Mg/ha on more productive sites. Total fuel consumption ranged from 15% in early spring burns to 92% in early fall burns. Organic horizons (litter and duff) composed 62–84% of the total fuel load. Consumption of the organic horizons ranged from 11 to 94%. Lower duff (Oa horizon) moisture content was 135% in the former and 15% in the latter. Consumption of the organic horizon was significantly correlated with lower duff moisture content (r2 = 0.51). More than 72% of all fuel was consumed after the flaming front had passed over an area. Postburn mineral soil exposure was strongly influenced by fuel consumption, season of burn, and characteristics of the site. In the late spring burns at one site, bare ground exposure was 3% before fire, 60% two months after fire, and 8% thirteen months after fire. There were slight to nonexistent increases in bare ground exposure from burns prescribed during early spring or late autumn (i.e., burns of low to moderate consumption).
Seasonal and genetic variation in frost hardiness of Eucalyptusdelegatensis
Authors: Hallam P. M. , Reid J. B.
Published: July 2007

Seasonal variation in frost hardiness of a range of provenances of Eucalyptusdelegatensis R.T. Bak. was examined in provenance trials at Tarraleah and Myrtle Bank, Tasmania, using a technique based upon the electrical conductivity of diffusate. Maximum hardiness was recorded in July and August, and seasonal variation reached 4.6 °C for individual provenances. The extreme minimum temperature recorded in 1983 was lower than in 1984. Corresponding to this difference the measured level of maximum hardiness was substantially greater in 1983 than in 1984. Substantial differences in frost hardiness occurred between provenances, the differences in mean lethal temperature between provenances being greatest (2.7 °C) when trees were hardened. These differences are sufficient to cause large differences in levels of survival and frost damage at Tarraleah. The Myrtle Bank site experienced less severe temperatures than the Tarraleah site, consequently provenances were found to develop substantially less frost hardiness. However, rankings of provenances were the same at both sites, suggesting that it may be possible to select frost-resistant provenances for Tasmania on the basis of a single test site. However, tests at maritime sites may not serve to indicate rankings for continental climates because the rankings determined in the Tasmanian trials differed markedly from rankings made by other workers at Pilot Hill in New South Wales. Studies with seedlings grown in controlled environments indicated that the rate of frost hardening in E. delegatensis (0.07°C/day) was slow compared with that of many northern hemisphere species but similar to rates reported for some other species of eucalypts. The rate of dehardening was at least twice as rapid as the rate of hardening. The results are consistent with the view that the frost hardiness of eucalypts is determined by both duration and severity of low night temperatures over the preceding 1 or 2 months.
THEORY OF THE GOOS-HÄNCHEN DISPLACEMENT IN TOTAL INTERNAL REFLECTION
Authors: SHI JIE-LONG , LI CHUN-FANG , WANG QI
Published: July 2007

Since the Goos-Hänchen (GH) effect is the displacement of the totally reflected beam at a dielectric interface from the position prediction by geometrical reflection, the concept of GH displacement is applicable only when the reflected beam retains the shape of the geometrically reflected or incident beam. The necessary and sufficient condition has been advanced for the totally reflected beam to retain the shape of the incident beam. Numerical simulations have been performed to confirm this condition. It has been shown that the GH displacement results from the mechanism of beam reshaping due to the linear dependence of the reflection phase shift upon the parallel component of the wave vector, in the interval in which the angular spectral distribution function of the incident beam is appreciable.
THE SIZE INFLUENCE OF SILICA MICROSPHERES ON PHOTONIC BAND GAP OF PHOTONIC CRYSTALS
Authors: MA XIYING , YAN ZHIJUN
Published: July 2007

The size influence of silica microspheres on the photonic band gap (PBG) of three-dimensional face-centered-cubic (fcc) photonic crystals (PCs) is studied by means of colloidal photonic crystals, which are self-assembled by the vertical deposition technique. Monodispersed SiO 2 microspheres with a diameter of 220–320 nm are synthesized using tetraethylorthosilicate (TEOS) as a precursor material. We find that the PBG of the PCs shifts from 450 nm to 680 nm with silica spheres increasing from 220 to 320 nm. In addition, the PBG moves to higher photon energy when the samples are annealed in a temperature range of 200–700°C. The large shift results from the decrease in refraction index of silica due to moisture evaporation.
A FAMILY OF NEW DISCRETE EQUATIONS ASSOCIATED WITH LOTKA–VOLTERRA LATTICE AND ITS INTEGRABLE COUPLINGS
Authors: SUN YE-PENG , CHEN DENG-YUAN , YANG YAN-ZHEN
Published: July 2007

A family of new discrete nonlinear equations associated with the Lotka–Volterra lattice is constructed by defining a novel algebraic system X. Moreover, some properties of the hierarchy are discussed. Furthermore, nonlinear integrable couplings of the resulting hierarchy are derived from an extended algebraic system [Formula: see text]. Finally, an example is given.
PRESSURE EFFECT ON THE MgB2 ELECTRON STRUCTURE FROM FIRST PRINCIPLE CALCULATIONS
Authors: CHEN LI
Published: July 2007

The electronic structure of MgB 2 with different lattice parameters, which represents the influence of pressure, has been studied from HF calculation. It has been found that the density of states at the Fermi level decreases with the decrease in lattice constant, which implies that the pressure can reduce the superconductivity of MgB 2. It was also found that more electrons are introduced from the Mg layer to the B layer with increasing pressure, resulting in the number of holes on the B layer being reduced, thus reducing superconductivity. The electron density population at different pressures clearly shows that the triangle-shaped electron distribution in the B plane, extended along the B–B bonds, indicates the typical sp2 orbitals. On the other hand, there is no covalency feature between Mg and B atoms, indicating the ionic bonding property between Mg and B layers.
MAXIMALLY ENTANGLED STATES FOR MANY TRAPPED IONS FROM SINGLE RESONANT INTERACTIONS
Authors: LI LIN , XU DAHAI , TIAN YONGHONG , YUAN XIUHUA
Published: July 2007

We propose an alternative scheme to generate the GHZ states and cluster states for many trapped ions illuminated by a single laser tuned to the first lower vibrational sideband. The distinct advantage of the present scheme is that it does not use the vibrational mode as the data bus and only requires a single resonant interaction. Thus the present scheme is very simple and the interaction time is very short, which is important in view of decoherence.
A 2.5D MODEL FOR THE EQUATIONS OF THE OCEAN AND THE ATMOSPHERE
Authors: CHEN Q. S. , LAMINIE J. , ROUSSEAU A. , TEMAM R. , TRIBBIA J.
Published: July 2007

The primitive equations (PEs) of the atmosphere and the ocean without viscosity are considered. A 2.5D model is introduced, whose motivation is described in the Introduction. A set of nonlocal boundary conditions is proposed, and well-posedness is established for the flows linearized around a constant velocity stratified flow; homogeneous and nonhomogeneous boundary conditions are considered. A related model of dimension 2.5, of physical interest but with fewer degrees of freedom, is also considered at the end.
SAINT VENANT COMPATIBILITY EQUATIONS IN CURVILINEAR COORDINATES
Authors: CIARLET PHILIPPE G. , MARDARE CRISTINEL , SHEN MING
Published: July 2007

We first establish that the linearized strains in curvilinear coordinates associated with a given displacement field necessarily satisfy compatibility conditions that constitute the "Saint Venant equations in curvilinear coordinates". We then show that these equations are also sufficient, in the following sense: If a symmetric matrix field defined over a simply-connected open set satisfies the Saint Venant equations in curvilinear coordinates, then its coefficients are the linearized strains associated with a displacement field. In addition, our proof provides an explicit algorithm for recovering such a displacement field from its linearized strains in curvilinear coordinates. This algorithm may be viewed as the linear counterpart of the reconstruction of an immersion from a given flat Riemannian metric.
Discordant proliferation and differentiation in pituitary tumor-transforming gene-null bone marrow stem cells
Authors: Rubinek Tami , Chesnokova Vera , Wolf Ido , Wawrowsky Kolja , Vlotides George , Melmed Shlomo
Published: July 2007

The mammalian securin, pituitary tumor-transforming gene ( Pttg), regulates sister chromatid separation during mitosis. Mice deficient in Pttg expression exhibit organ-specific hypoplasia of the testis, spleen, pituitary, and postmaturity pancreatic β-cells, pointing to a possible adult stem cell defect. Bone marrow stem cells (BMSCs) contribute to bone, cartilage, and fat tissue repair and regeneration, and multipotent adult progenitor cells (MAPCs) have broader differentiation ability. Bone marrow cells derived under MAPC conditions are involved in a spectrum of tissue repair. We therefore tested whether Pttg deletion affects stem cell proliferation and differentiation. BMSCs were isolated under MAPC conditions, although unlike MAPCs, wild-type (WT) and Pttg−/− BMSCs do not express octamer-binding transcription factor 4 and are stem cell antigen-I positive. WT and Pttg−/− cells did not differ in their ability to differentiate into adipogenic, osteogenic, or hepatocyte-like cells or in phenotypic markers. Cells underwent >100 population doublings, with no observed transforming events. Pttg-null BMSCs replicated 27% slower than WT BMSCs, and under hypoxic conditions, this difference widened. Although apoptosis was not enhanced in Pttg−/− cells, Pttg−/− BMSC senescence-associated β-galactosidase activity was elevated, consistent with enhanced p21 protein levels. Using gene array assays, DNA repair genes were shown to be upregulated in Pttg−/− BMSCs, whereas genes involved in cell cycle progression, including cyclin D1, were decreased. Separase, the protease regulated by Pttg, has been implicated in DNA damage repair and was downregulated in Pttg−/− BMSCs. Separase was constitutively phosphorylated in Pttg−/− cells, a modification likely serving as a compensatory mechanism for Pttg deletion. The results indicate that Pttg deletion reduces BMSC proliferation, renders cells more sensitive to hypoxia, and enhances senescent features, thus pointing to a role for Pttg in the maintenance and proliferation of BMSCs.
Urethral closure mechanisms during sneezing-induced stress in anesthetized female cats
Authors: Julia-Guilloteau V. , Denys P. , Bernabé J. , Mevel K. , Chartier-Kastler E. , Alexandre L. , Giuliano F.
Published: July 2007

During stress-induced increase in abdominal pressure, urinary continence is maintained by urethral closure mechanisms. Active urethral response has been studied in dogs and rats. Such an active urethral response is also believed to occur in humans during stress events. We aimed to investigate urethral closure mechanisms during sneezing in cats. Urethral pressures along the urethra (UP1–UP4), with microtip transducer catheters with UP4 positioned in the distal urethra where the external urethral sphincter (EUS) is located, and intravesical pressure were measured, and abdominal wall, anal sphincter (AS), levator ani (LA), and EUS electromyograms (EMGs) were recorded during sneezing under closed-abdomen and open-abdomen conditions in eight anesthetized adult female cats. Proximal and middle urethral response induced by sneezing was not different from bladder response. Distal urethral response was greater compared with proximal and middle urethral and bladder response. In the open-abdomen bladder, proximal and middle urethral responses were similarly decreased and distal urethral response was unchanged compared with the closed-abdomen bladder. Bladder and urethral responses were positively correlated to sneeze strength. EUS, LA, and AS EMGs increased during sneezing. No urine leakage was observed, regardless of the strength of sneeze. In cats urethral closure mechanisms are partly passive in the proximal and middle urethra and involve an active component in the distal urethra that is believed to result from EUS and possibly LA contractions. Because central serotonin exerts similar effects on the lower urinary tract in cats and humans, the cat may represent a relevant model for pharmacological studies on continence mechanisms.
Arterial remodeling and plasma volume expansion in caveolin-1-deficient mice
Authors: Albinsson Sebastian , Shakirova Yulia , Rippe Anna , Baumgarten Maria , Rosengren Bert-Inge , Rippe Catarina , Hallmann Rupert , Hellstrand Per , Rippe Bengt , Swärd Karl
Published: July 2007

Caveolin-1 (Cav-1) is essential for the morphology of membrane caveolae and exerts a negative influence on a number of signaling systems, including nitric oxide (NO) production and activity of the MAP kinase cascade. In the vascular system, ablation of caveolin-1 may thus be expected to cause arterial dilatation and increased vessel wall mass (remodeling). This was tested in Cav-1 knockout (KO) mice by a detailed morphometric and functional analysis of mesenteric resistance arteries, shown to lack caveolae. Quantitative morphometry revealed increased media thickness and media-to-lumen ratio in KO. Pressure-induced myogenic tone and flow-induced dilatation were decreased in KO arteries, but both were increased toward wild-type (WT) levels following NO synthase (NOS) inhibition. Isometric force recordings following NOS inhibition showed rightward shifts of passive and active length-force relationships in KO, and the force response to α1-adrenergic stimulation was increased. In contrast, media thickness and force response of the aorta were unaltered in KO vs. WT, whereas lumen diameter was increased. Mean arterial blood pressure during isoflurane anesthesia was not different in KO vs. WT, but greater fluctuation in blood pressure over time was noted. Following NOS inhibition, fluctuations disappeared and pressure increased twice as much in KO (38 ± 6%) compared with WT (17 ± 3%). Tracer-dilution experiments showed increased plasma volume in KO. We conclude that NO affects blood pressure more in Cav-1 KO than in WT mice and that restructuring of resistance vessels and an increased responsiveness to adrenergic stimulation compensate for a decreased tone in Cav-1 KO mice.
Interaction between myosin heavy chain and troponin isoforms modulate cardiac myofiber contractile dynamics
Authors: Chandra Murali , Tschirgi Matthew L. , Ford Steven J. , Slinker Bryan K. , Campbell Kenneth B.
Published: July 2007

Coordinated expression of species-specific myosin heavy chain (MHC) and troponin (Tn) isoforms may bring about a dynamic complementarity to match muscle contraction speed with species-specific heart rates. Contractile system function and dynamic force-length measurements were made in muscle fibers from mouse and rat hearts and in muscle fibers after reconstitution with either recombinant homologous Tn or orthologous Tn. The rate constants of length-mediated cross-bridge (XB) recruitment ( b) and tension redevelopment ( ktr) of mouse fibers were significantly faster than those of rat fibers. Both the tension cost (ATPase/tension) and rate constant of length-mediated XB distortion ( c) were higher in the mouse than in the rat. Thus the mouse fiber was faster in all dynamic and functional aspects than the rat fiber. Mouse Tn significantly increased b and ktrin rat fibers; conversely, rat Tn significantly decreased b and ktrin mouse fibers. Thus the length-mediated recruitment of force-bearing XB occurs much more rapidly in the presence of mouse Tn than in the presence of rat Tn, demonstrating that the speed of XB recruitment is regulated by Tn. There was a significant interaction between Tn and MHC such that changes in either Tn or MHC affected the speed of XB recruitment. Our data demonstrate that the dynamics of myocardial contraction are different in the mouse and rat hearts because of sequence heterogeneity in MHC and Tn. At the myofilament level, coordinated expression of complementary regulatory contractile proteins produces a functional dynamic phenotype that allows the cardiovascular systems to function effectively at different heart rates.
Organ cross talk modulates pelvic pain
Authors: Rudick Charles N. , Chen Michael C. , Mongiu Anne K. , Klumpp David J.
Published: July 2007

Interstitial cystitis (IC) is a chronic bladder inflammatory disease of unknown etiology that is often regarded as a neurogenic cystitis. IC is associated with urothelial lesions, voiding dysfunction, and pain in the pelvic/perineal area, and diet can exacerbate IC symptoms. In this study, we used a murine neurogenic cystitis model to investigate the development of pelvic pain behavior. Neurogenic cystitis was induced by the injection of Bartha's strain of pseudorabies virus (PRV) into the abductor caudalis dorsalis tail base muscle of female C57BL/6J mice. Infectious PRV virions were isolated only from the spinal cord, confirming the centrally mediated nature of this neurogenic cystitis model. Pelvic pain was assessed using von Frey filament stimulation to the pelvic region, and mice infected with PRV developed progressive pelvic pain. Pelvic pain was alleviated by 2% lidocaine instillation into either the bladder or the colon but not following lidocaine instillation into the uterus. The bladders of PRV-infected mice showed markers of inflammation and increased vascular permeability compared with controls. In contrast, colon histology was normal and vascular permeability was unchanged, suggesting that development of pelvic pain was due only to bladder inflammation. Bladder-induced pelvic pain was also exacerbated by colonic administration of a subthreshold dose of capsaicin. These data indicate organ cross talk in pelvic pain and modulation of pain responses by visceral inputs distinct from the inflamed site. Furthermore, these data suggest a mechanism by which dietary modification benefits pelvic pain symptoms.
Vasopressin V2receptor expression along rat, mouse, and human renal epithelia with focus on TAL
Authors: Mutig K. , Paliege A. , Kahl T. , Jöns T. , Müller-Esterl W. , Bachmann S.
Published: July 2007

In renal epithelia, vasopressin influences salt and water transport, chiefly via vasopressin V2receptors (V2Rs) linked to adenylyl cyclase. A combination of vasopressin-induced effects along several distinct portions of the nephron and collecting duct system may help balance the net effects of antidiuresis in cortex and medulla. Previous studies of the intrarenal distribution of V2Rs have been inconclusive with respect to segment- and cell-type-related V2R expression. Our study therefore aimed to present a high-resolution analysis of V2R mRNA expression in rat, mouse, and human kidney epithelia, supplemented with immunohistochemical data. Cell types of the renal tubule were identified histochemically using specific markers. Pronounced V2R signal in thick ascending limb (TAL) was corroborated functionally; phosphorylation of Na+-K+-2Cl−cotransporter type 2 (NKCC2) was established in cultured TAL cells from rabbit and in rats with diabetes insipidus that were treated with the V2R agonist desmopressin. We found solid expression of V2R mRNA in medullary TAL (MTAL), macula densa, connecting tubule, and cortical and medullary collecting duct and weaker expression in cortical TAL and distal convoluted tubule in all three species. Additional V2R immunostaining of kidneys and rabbit TAL cells confirmed our findings. In agreement with strong V2R expression in MTAL, kidneys from rats with diabetes insipidus and cultured TAL cells revealed sharp, selective increases in NKCC2 phosphorylation upon desmopressin treatment. Macula densa cells constitutively showed strong NKCC2 phosphorylation. Results suggest comparably significant effects of vasopressin-induced V2R signaling in MTAL and in connecting tubule/collecting duct principal cells across the three species. Strong V2R expression in macula densa may be related to tubulovascular signal transfer.
Analyzing Octopus Movements Using Three-Dimensional Reconstruction
Authors: Yekutieli Yoram , Mitelman Rea , Hochner Binyamin , Flash Tamar
Published: July 2007

Octopus arms, as well as other muscular hydrostats, are characterized by a very large number of degrees of freedom and a rich motion repertoire. Over the years, several attempts have been made to elucidate the interplay between the biomechanics of these organs and their control systems. Recent developments in electrophysiological recordings from both the arms and brains of behaving octopuses mark significant progress in this direction. The next stage is relating these recordings to the octopus arm movements, which requires an accurate and reliable method of movement description and analysis. Here we describe a semiautomatic computerized system for 3D reconstruction of an octopus arm during motion. It consists of two digital video cameras and a PC computer running custom-made software. The system overcomes the difficulty of extracting the motion of smooth, nonrigid objects in poor viewing conditions. Some of the trouble is explained by the problem of light refraction in recording underwater motion. Here we use both experiments and simulations to analyze the refraction problem and show that accurate reconstruction is possible. We have used this system successfully to reconstruct different types of octopus arm movements, such as reaching and bend initiation movements. Our system is noninvasive and does not require attaching any artificial markers to the octopus arm. It may therefore be of more general use in reconstructing other nonrigid, elongated objects in motion.
Deconstructing the Genome with Cinema
Authors: Harp Gabriel A.
Published: July 2007

Evidence from language, history and form suggest an analogy between the cinema and the genome. The author describes some of the relationships between cinema and the genome and points to opportunities for discovering unmarked categories within the genome and new methods of representation. This is accomplished by evaluating existing metaphors presented for the understanding of genetics and revealing how current scientific understanding and social concerns suggest a cinematic alternative. The formal principles of function, difference and development mediate discussion and serve as heuristics for investigating creative opportunities.
Fractal Graphic Designer Anton Stankowski
Authors: Shlyk Vladimir A.
Published: July 2007

The author introduces an outstanding master of graphic design and photography, Anton Stankowski, as a fractal artist. Stankowski saw his challenge as inventing a visual graphic language capable of depicting natural and technological processes and abstract notions in an aesthetic and comprehensible way. Many of Stankowski's works demonstrate fractal-like characteristics. Analysis of his theory of design provides convincing evidence that this is not accidental. Stankowski used these features consciously. He devised and applied a principle of organizing forms in pictures by means of two components, branching and regeneration, both of which are properties of self-similarity and the underlying bases of fractals.
Islamic Insurance: National Features and Legal Regulation
Authors: Bekkin Renat
Published: July 2007

The present paper studies Islamic insurance (takaful) as opposed to conventional one. The first part of the paper covers, among other things, such issues as nature and historic roots of Islamic insurance, early forms of Islamic insurance and narrates the disputes among Muslim scholars concerning the compatibility of insurance with Islamic Shariah. The second part deals with history and emergence of Islamic insurance in the modern financial market, as well as the practice of Islamic insurance in different countries. The third part discusses the feasibility of Islamic insurance in Russia in the current legal framework. The paper contains comprehensive glossary of related terms.
Customs Regimes and the Materiality of Global Mobility
Authors: Chalfin Brenda
Published: July 2007

Focusing on customs operations at the Port of Rotterdam, this essay investigates the problematic of commercial governance at a historical moment characterized by the unprecedented volume and velocity of cross-border and transoceanic trade and an increasingly globalized security mandate. Although Netherlands Customs officers, facilities, and regulatory authority are visibly evident at the Port of Rotterdam, Customs operates largely through forms of indirect control rather than direct oversight. These trends reflect the influence of the World Trade Organization and World Customs Organization as well as International Maritime Organization and U.S. Customs and Border Protection provisions. They also belie a strongly neoliberal move toward minimal or consolidated government, backed up when necessary by security. They equally entail processes of private government involving the delegation of responsibilities to private authorities, the ceding of commercial privilege to select firms, and dependence on information and management models from the private sector.