bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigating optimal aggregation interval sizes of loop detector data for freeway travel-time estimation and prediction
Authors: Park Dongjoo , You Soyoung , Rho Jeonghyun , Cho Hanseon , Lee Kangdae
Published: April 2009

With recent increases in the deployment of intelligent transportation system (ITS) technologies, traffic management centers have the ability to obtain and archive large amounts of data regarding the traffic system. These data can then be employed in estimations of current conditions and the prediction of future conditions on the roadway network. In this paper, we propose a general solution methodology for the identification of the optimal aggregation interval sizes of loop detector data for four scenarios (i) link travel-time estimation, (ii) corridor / route travel-time estimation, (iii) link travel-time forecasting, and (iv) corridor / route travel-time forecasting. This study applied cross validated mean square error (CVMSE) model for the link and route travel-time estimations, and a forecasting mean square error (FMSE) model for the link and corridor / route travel-time forecasting. These models were applied to loop detector data obtained from the Kyeongbu expressway in Korea. It was found that the optimal aggregation sizes for the travel-time estimation and forecasting were 3 to 5 min and 10 to 20 min, respectively.
Hydraulic jump in a sloped triangular channel
Authors: Debabeche Mahmoud , Cherhabil Sonia , Hafnaoui Amin , Achour Bachir
Published: April 2009

The hydraulic jump in a sloped triangular channel of 90° central angle is theoretically and experimentally examined. The study aims to determine the effect of the channel's slope on the sequent depth ratio of the jump. A theoretical relation is proposed for the inflow Froude number as function of the sequent depth ratio and the channel slope. An experimental analysis is also proposed to find a better formulation of the obtained relation. For this motive, six positive slopes are tested. The relations obtained are recommended for designing irrigation ditches.
Resilient modulus properties of granular highway materials
Authors: Stolle Dieter , Guo Peijun , Liu Ying
Published: April 2009

An essential component of the new Guide for mechanistic–empirical design of new and rehabilitated pavement structures for the design of flexible pavement structures is the use of resilient modulus for base / subbase materials and subgrade soils. This study reports on resilient modulus (Mr) test results for unbound pavement materials that were obtained according to the American Association of State Highway and Transportation Officials (AASHTO) standard T307–99. Laboratory tests were performed on 36 representative aggregates from across Ontario and empirical relations between Mr and the bulk stress were investigated, as well as the sensitivity of Mr to moulding water content and gradation. This paper proposes to replace the nonlinear relation between resilient modulus and bulk stress with a linear relation between the two, taking into account the uncertainties that include the effect of varying water content through stochastic analysis. The effects of deviatoric stress on resilient modulus were found to be negligible for the granular aggregates that were tested. The use of a linear relation was computationally more efficient than the use of a nonlinear law; however, differences in strain predictions were observed. The findings from the finite element simulations were consistent to other studies that compared solutions using various constitutive models.
Actions microclimatique et environnementale des ouvrages d’art routiers
Authors: Conciatori David , Brühwiler Eugen , Dumont André-Gilles
Published: April 2009

Les différentes zones d’un ouvrage d’art routier sont étudiées en fonction de leur degré d’exposition au microclimat environnant. Les conditions climatiques provenant de stations météorologiques et la cinétique des véhicules permettent de définir des zones d’exposition aux produits salants et au climat. Une division judicieuse d’un ouvrage en éléments structuraux en fonction de son exposition permet de prendre en considération l’importante variabilité spatiale et de définir des zones de sensibilité équivalente face aux détériorations. Sur la base de stations météorologiques suisses, d’un monitoring d’un ouvrage d’art routier, d’enquêtes auprès des autorités publiques, de mesures ponctuelles in situ et de recherches bibliographiques, cet article met en exergue le microclimat des structures de manière précise. Cette approche permet de définir les différentes zones d’exposition des ouvrages, à savoir les zones de brouillard salin, d’éclaboussures et de stagnation d’eau et de définir l’importance du microclimat en vue de prédire l’évolution des détériorations des structures.
Interpreting nonstationary environmental cycles as amplitude-modulated (AM) signalsA paper submitted to the Journal of Environmental Engineering and Science.
Authors: Fleming Sean W. , Hudson Peter , Quilty Edward J.
Published: April 2009

Inspired by an analogy to AM radio signals, amplitude modulation (AM) is proposed here as a useful view of nonstationary environmental periodicities, and applied to hydrologic and air quality datasets. Both example time series considered exhibit seasonally evolving diel cycles, with large (small) daily cycle amplitudes in summer (winter). The carrier wave is taken to be a sinusoidal daily cycle; this is multiplied by an information signal consisting of a sinusoidal annual cycle, forming an envelope to the diel variations. Our results suggest that amplitude modulation may offer a novel, compact, and accessible perspective, both qualitatively and quantitatively, on the net phenomenological behaviour arising from highly complex, nonlinear, and diverse environmental process dynamics. Physical interpretations, synergies with common environmental time series processing or analysis methods (Kolmogorov-Zurbenko filtering, classical spectral analysis, and singular systems analysis), and potential future research directions are also explored.
Assessment of the use of the vapour equilibrium technique in controlled-suction tests
Authors: Pintado X. , Lloret A. , Romero E.
Published: April 2009

This paper presents a study on suction control methodology using the vapour equilibrium technique. To reduce the time needed to reach equilibrium, humid air is forced to flow through the sample or on its boundaries. An analysis of the physical processes that occur in the tested soil samples using a numerical approach is included. The test is numerically simulated and the key parameters of the process calibrated. A sensitivity analysis of the unmeasured parameters and variables is performed. It could be observed that forcing humid air to flow through the sample reduces the equalization time, but the results from the numerical simulations highlight that this flow must be carefully applied to avoid reaching, under steady-state conditions, a different suction than that wished for. When the circulation of air along the boundaries is slow, an increase in air velocity tends to increase the rate of suction changes in the sample. However, if the circulation of air increases over some limit, the flow conditions inside the soil control the development of the process.
Oxygen diffusion and consumption in low-sulphide tailings covers
Authors: Demers Isabelle , Bussière Bruno , Mbonimpa Mamert , Benzaazoua Mostafa
Published: April 2009

Acid-generating tailings can be reclaimed using oxygen barrier covers in humid climates, such as in Quebec. A single-layer low-sulphide tailings cover is an attractive alternative to traditional water covers to maximize the impoundment’s storage capacity. Low-sulphide tailings can serve as a moisture-retaining material to limit oxygen diffusion, and their residual sulphides can consume the diffusive oxygen that still gets through the cover. A laboratory experiment using instrumented columns was initiated to confirm the efficiency of a low-sulphide tailings monolayer cover placed over acid-generating tailings to reduce the oxygen flux reaching the reactive tailings. Oxygen concentration profiles were measured over the thickness of the cover and oxygen fluxes were calculated to evaluate the effect of three parameters on these fluxes: water table level, cover sulphide content, and cover thickness. Oxygen fluxes at the bottom of the low-sulphide tailings cover layer, calculated using oxygen gradient and estimated effective diffusion coefficient and predicted using Vadose/W, were lower than 1.5 mol·m−2·year−1. These results suggest that a low-sulphide tailings cover with an elevated water table can reduce oxygen migration and potentially limit acid mine drainage generation.
The effects of timber harvest, forest fire, and herbivores on regeneration of deciduous trees in boreal pine-dominated forests
Authors: den Herder Michael , Kouki Jari , Ruusila Vesa
Published: April 2009

Forest management, fire, and herbivores are the major factors affecting regeneration of deciduous trees in boreal forests. In a large-scale experiment, we manipulated the use of prescribed burning, the level of green-tree retention and the presence of moose ( Alces alces L.) and hare ( Lepus timidus L. and Lepus europaeus Pallas) to study their effects on early regeneration of three native pioneer tree species, i.e., rowan ( Sorbus aucuparia L.), aspen ( Populus tremula L.), and silver birch ( Betula pendula Roth). Green-tree retention enhanced survival of all tested tree species. Prescribed burning enhanced the survival rate of birch and rowan, but aspen survival was only enhanced by burning on clearcuts and areas with 50 m3/ha of retention trees. Excluding moose enhanced rowan growth and birch survival. Aspen growth and survival was enhanced when both moose and hare were excluded. Seedlings were most frequently browsed on clearcuts, and most seedling mortality was caused by voles or hare. At low densities, the effect of moose on pioneer trees may be smaller than that of other herbivores or the fire–management regime. Considering the large number of species depending on pioneer trees, the results support the use of tree retention and fire as useful management alternatives not only to promote biodiversity but also to enhance regeneration of deciduous trees and reduce herbivore damage.
Impact of seasonally frozen soil on germinability and antioxidant enzyme activity of Picea asperata seeds
Authors: Qin Jihong , Liu Qing
Published: April 2009

In the subalpine zone of the Qinghai–Tibetan Plateau of China, Dragon spruce (Picea asperata Mast.) is commonly used for reforestation. The aim of the present work was to study the effects of seasonally frozen soil on the germination of P. asperata seeds and to investigate whether these effects were associated with resumption of the antioxidant defense system. The nonfrozen treatment resulted in near failure of germination (1%) and was associated with relatively high levels of hydrogen peroxide (H2O2) and low activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxide (APX). Germination of P. asperata seeds at 10 cm under the seasonally frozen soil was higher than that at 5 cm by 26%; this higher germination rate was associated with the recovery of SOD, CAT, and APX activities. The levels of malondialdehyde (MDA) in seeds from seasonally frozen treatments were higher than those in the nonfrozen treatment, implying greater lipid peroxidation and that frozen seeds might have suffered from oxidative stress. The results indicate that seasonally frozen soil facilitated the germination of P. asperata seeds and that germination was closely related to the resumption of antioxidant enzymes activity. Overall, these findings suggest that the disappearance of seasonally frozen ground caused by global warming might result in failure of regeneration of P. asperata.
Estimating Quebec provincial forest resources using ICESat/GLAS
Authors: Nelson Ross , Boudreau Jonathan , Gregoire Timothy G. , Margolis Hank , Næsset Erik , Gobakken Terje , Ståhl Göran
Published: April 2009

Ground plots, airborne profiling and space lidar (light detection and ranging) measurements of canopy height and crown closure, space radar topographic data, a Landsat cover type map, and a vegetation zone map were used in a model-assisted, two-phase sampling design to estimate the aboveground biomass and carbon resources of Quebec. It was determined that a simple random sampling estimator, with covariance terms added, could be used to quantify the variability of regional Geoscience Laser Altimeter System (GLAS) biomass estimates where interorbit distances are, on average, ≥15 km apart. Prediction error increased standard errors, on average, 24.4%, 4.6%, and 2.8% at the cover type, vegetation zone, and provincial levels, respectively. Inclusion of the covariance term in the calculation of grouped cover type variances increased the vegetation zone standard errors up to 3.7 times and the provincial standard errors 15.6 times. In the southern commercial forests of Quebec, GLAS underestimated ground-based biomass values by 7.3% (stratified linear model) and 10.2% (nonstratified linear model). Quebec forests support 2.57 ± 0.33 gigatonnes of carbon (nonstratified linear model). Approximately 25% of that carbon was found to be located in two southern vegetation zones (northern hardwood and mixedwood), another 25% in two northern vegetation zones (taiga and treed tundra), and the remaining 50% in the boreal zone.
Molecular evidence for fragmentation among populations of Taxus wallichiana var. mairei, a highly endangered conifer in China
Authors: Zhang Xue-Mei , Gao Lian-Ming , Möller Michael , Li De-Zhu
Published: April 2009

Taxus wallichiana var. mairei (Lemée & Léveillé) L. K. Fu & Nan Li is a highly endangered conifer in China. It is dioecious and wind pollinated, with seed dispersal by animals. Extant natural populations on mainland China and Taiwan are highly scattered, largely as a result of habitat loss and overexploitation. Intersimple sequence repeat (ISSR) markers were employed to assess the genetic structure among 464 individuals from 17 populations across the variety’s distribution range in the Sino–Japanese and Malesian floristic subkingdoms. ISSRs revealed a high genetic diversity (percentage of polymorphic loci = 98.4%, Nei’s gene diversity = 0.3467, Shannon’s information index = 0.5152) at the species level and high differentiation among populations (coefficient of gene differentiation = 0.4066; θB = 0.4376). Gene flow among populations was found to be limited to the mainland populations. A UPGMA (unweighted pair group method with arithmetic mean) dendrogram suggests that the population in Taiwan is genetically the most isolated, while among the mainland populations a trend of an east–west split is suggested. This finding is supported by the analysis of molecular variance. The pattern of genetic variation suggests that the extant distribution of T. wallichiana var. mairei is the result of the fragmentation of a historically more continuous distribution. Conservation measures for this highly endangered plant are discussed, and an integrated approach to increase plant density and connectivity among the remaining populations is suggested.
Long-term effects of tanoak competition on Douglas-fir stand development
Authors: Harrington Timothy B. , Tappeiner John C.
Published: April 2009

In 1- to 2-year-old Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco var. menziesii) plantations near Cave Junction and Glendale, Oregon, sprout clumps of tanoak (Lithocarpus densiflorus (Hook. & Arn.) Rehd.) and other hardwoods were removed with herbicides in April 1983 to leave relative covers of 0%, 25%, 50%, or 100% of the nontreated cover, which averaged 15%. In 1996 (Cave Junction) and 1998 (Glendale), precommercial thinning (PCT) of Douglas-fir and cutting of nonconifer woody species were operationally applied across the four densities of tanoak. In 2005, Douglas-fir in 0% relative cover of tanoak averaged 5–8 cm larger at breast height and 3–6 m taller, and had two to four times the net stand volume of those growing in 100% relative cover. From 1999 to 2005, Douglas-fir stand growth accelerated more rapidly in tanoak relative covers of 0% and 25% than in covers of 50% and 100%. Differential development of Douglas-fir and hardwoods in relative covers of 0%, 25%, and 100%, followed by selection of crop trees via PCT, resulted in three distinct stand structures: pure stands of Douglas-fir with a single canopy layer 12–16 m tall, mixed stands with overstory Douglas-fir (12 m) and midstory hardwoods (7 m), and mixed stands with a single canopy layer (8–9 m).
Improved nutritional status of Cupressus lusitanica when grown adjacent to Pinus radiata
Authors: Watt Michael S. , Davis Murray R. , Parfitt Roger L.
Published: April 2009

We examined how a mixture of Pinus radiata D. Don and Cupressus lusitanica Mill. influences foliage element concentrations at 20 sites, covering a fertility gradient. Foliage element concentrations of plants at plot boundaries, where the two species grew adjacent to each other, were compared with those of plants at plot centres, where they were surrounded by plants of the same species. For C. lusitanica, plot position significantly affected nitrogen (N), phosphorus (P), and sulphur (S) with concentrations of these elements at the plot boundary exceeding concentrations at the plot centre by 10%–14%. For P. radiata, plants at the plot boundary had a significantly greater P concentration and lower N/P ratio than plants at the centre, but differences between positions were less than that for C. lusitanica (<7%). For C. lusitanica, the difference between foliage concentrations of N and P at the plot boundary and centre significantly declined as the mean plot concentrations of these elements increased. It is likely that C. lusitanica at the boundary benefited from the greater availability of N, P, and S in the root rhizosphere, where they were mobilized from soil organic matter by the ectomycorrhizae of P. radiata. We also suggest that P. radiata at the plot boundary may have benefited from mobilization of P by the endomycorrhizae of C. lusitanica.
Influence of tree species on epiphytic macrolichens in temperate mixed forests of northern Italy
Authors: Nascimbene Juri , Marini Lorenzo , Nimis Pier Luigi
Published: April 2009

Tree species is a key factor in shaping epiphytic lichen communities. In managed forests, tree species composition is mainly controlled by forest management, with important consequences on lichen diversity. The main aim of this work was to evaluate the differences at tree level in macrolichen richness and composition between Abies alba Mill. and Fagus sylvatica L. in a temperate mixed forest in northern Italy, in addition to evaluating two different proportions of the two species at the stand level. Abies alba and F. sylvatica host lichen communities including several rare and sensitive species. Our findings indicate that both tree species were important for lichen diversity, since they hosted different communities. However, F. sylvatica proved to be a more favourable hosting tree for several rare and sensitive species. Species associated with A. alba were mainly acidophytic lichens, while those associated with F. sylvatica were foliose hygrophytic lichens, mainly establishing over bryophytes. The frequency of the flagship species Lobaria pulmonaria (L.) Hoffm. was a valuable predictor of cyanolichen richness and was useful in identifying sites hosting lichen communities that are potentially more sensitive to thinning and human disturbance. The results support the relevance of mixed A. alba – F. sylvatica formations among European habitats worthy of conservation.
Conifer regeneration in stand-replacement portions of a large mixed-severity wildfire in the Klamath–Siskiyou Mountains
Authors: Donato Daniel C. , Fontaine Joseph B. , Campbell John L. , Robinson W. Douglas , Kauffman J. Boone , Law Beverly E.
Published: April 2009

Large-scale wildfires (∼104–106ha) have the potential to eliminate seed sources over broad areas and thus may lead to qualitatively different regeneration dynamics than in small burns; however, regeneration after such events has received little study in temperate forests. Following a 200 000 ha mixed-severity wildfire in Oregon, USA, we quantified (1) conifer and broadleaf regeneration in stand-replacement patches 2 and 4 years postfire; and (2) the relative importance of isolation from seed sources (live trees) versus local site conditions in controlling regeneration. Patch-scale conifer regeneration density (72%–80% Douglas-fir ( Pseudotsuga menziesii (Mirb). Franco)) varied widely, from 127 to 6494 stems·ha–1. Median densities were 1721 and 1603 stems·ha–12 and 4 years postfire, respectively, i.e., ∼12 times prefire overstory densities (134 stems·ha–1). Because of the complex burn mosaic, ∼58% of stand-replacement area was ≤200 m from a live-tree edge (seed source), and ∼81% was ≤400 m. Median conifer density exceeded 1000 stems·ha–1out to a distance of 400 m from an edge before declining farther away. The strongest controls on regeneration were distance to live trees and soil parent material, with skeletal coarse-grained soils supporting lower densities (133 stems·ha–1) than fine-grained soils (729–1492 stems·ha–1). Other site factors (e.g., topography, broadleaf cover) had little association with conifer regeneration. The mixed-severity fire pattern strongly influenced the regeneration process by providing seed sources throughout much of the burned landscape.
NEW THERMO EXCITATION STATES AND OPERATIONS IN THERMO FIELD DYNAMICS
Authors: XU XUE-FEN , ZHU SHIQUN
Published: April 2009

According to the thermo field dynamics proposed by Takahashi–Umezawa, the Hamiltonian h = a†a - ã†ã and h|n, ñ〉 = 0 of the original optical field excitation state |n〉 and its tilde state |ñ〉 in the Hilbert space cannot embody the eigenvalue spectrum of h. To avoid the weakness, new thermo excitation states are successfully constructed by introducing appropriate thermo excitation operators. It is noted that they are entangled states. Applications of the new thermo excitation state in constructing new thermo squeezed state and phase state are also presented.
UNDEFORMED (ADDITIVE) ENERGY CONSERVATION LAW IN DOUBLY SPECIAL RELATIVITY
Authors: MANDANICI GIANLUCA
Published: April 2009

All the Doubly Special Relativity (DSR) models studied in literature so far involve a deformation of the energy conservation rule that forces us to release the hypothesis of the additivity of the energy for composite systems. In view of the importance of the issue for a consistent formulation of a DSR statistical mechanics and a DSR thermodynamics, we show that DSR models preserving the usual (i.e. additive) energy conservation rule can be found. These models allow the construction of a DSR-covariant extensive energy. The implications of the analysis for the dynamics of DSR-covariant multiparticle systems are also briefly discussed.
PARALLEL FFT ALGORITHMS ON NETWORK-ON-CHIPS
Authors: BAHN JUN HO , YANG JUNG SOOK , HU WEN-HSIANG , BAGHERZADEH NADER
Published: April 2009

This paper presents parallel FFT algorithms with different degree of computation and communication overheads for multiprocessors in a Network-on-Chip (NoC) environment. Of the three parallel FFT algorithms presented in this paper, we propose two parallel FFT algorithms for a 2D NoC that can contain a variable number of processing elements (PEs) and one is a reference parallel FFT algorithm for comparison. A parallel FFT algorithm we propose increases performance by assigning well-balanced computation tasks to PEs. The execution times are reduced because the algorithm uses data locality well to avoid unnecessary data exchanges among PEs and removes the overall idle periods by2 a balanced task scheduling. An enhanced version of this algorithm is suggested in which communication traffic is reduced. In this algorithm, returning transformed data to an original PE after one computation stage before sending them to a next PE for the following stage is removed. Instead, we propose a method that enables to keep regularity of the data communication and computations with twiddle factors. According to the simulation result from our cycle-accurate SystemC NoC model with a parametrizable 2-D mesh architecture, and the analysis of the algorithms in time and complexity, our proposed algorithms are shown to outperform the reference parallel FFT algorithm and FFT implementations on TI Digital Signal Processors (DSPs) that have similar specifications to our simulation environment.
OPTIMIZED REVERSIBLE MULTIPLIER CIRCUIT
Authors: HAGHPARAST MAJID , MOHAMMADI MAJID , NAVI KEIVAN , ESHGHI MOHAMMAD
Published: April 2009

Reversible logic circuits have received significant attention in quantum computing, low power CMOS design, optical information processing, DNA computing, bioinformatics, and nanotechnology. This paper presents two new 4 × 4 bit reversible multiplier designs which have lower hardware complexity, less garbage bits, less quantum cost and less constant inputs than previous ones, and can be generalized to construct efficient reversible n × n bit multipliers. An implementation of reversible HNG is also presented. This implementation shows that the full adder design using HNG is one of the best designs in term of quantum cost. An implementation of MKG is also presented in order to have a fair comparison between our proposed reversible multiplier designs and the existing counterparts. The proposed reversible multipliers are optimized in terms of quantum cost, number of constant inputs, number of garbage outputs and hardware complexity. They can be used to construct more complex systems in nanotechnology.
CHRONO-SCHEDULING: A SIMPLIFIED DYNAMIC SCHEDULING ALGORITHM FOR TIMING PREDICTABLE PROCESSORS
Authors: DIAZ-DEL-RIO F. , SEVILLANO J. L. , VICENTE S. , JIMENEZ-MORENO G. , CIVIT-BALCELLS A.
Published: April 2009

We propose a simpler and latency-reduced instruction scheduler, called chrono-scheduling algorithm, which avoids large and difficult instruction wake-up in order to reduce power consumption and latencies. The key idea of this scheduler is to extract and record all possible information about the future execution of an instruction during its issue, so as not to look for this information again and again during wait stages at the reservation stations. Therefore, an instruction can be issued with the information about at what cycle its operands must be captured and when it must be executed. The first implementation is targeted to processors that have constant latencies like many embedded microcontrollers, most vector processors without data cache, etc. Its main advantages are: no tags, no renaming, and much simpler waiting stations. When compared with classical dynamic schedulers, chrono-scheduling provides approximately the same CPI but with simpler overall circuitry and presumably higher clock speed (mainly because of its simplified stations).
SYMMETRY-RELATIONS FOR ELASTICALLY DEFORMED PERIODIC ROD-STRUCTURES
Authors: LUKKASSEN DAG , MEIDELL ANNETTE , PIATNITSKI ANDREY , SHAMAEV ALEXEY
Published: April 2009

In this paper we study periodic elastic rod-structures which are locally anisotropic and symmetric with respect to some plane. In order to find the effective behavior and approximate local behavior (so-called corrector-results) of such structures, one has to solve a finite number of boundary-value problems on one period of the rod-structure, the cell problem. For the solution of the cell-problem, it is shown that the components of the displacement satisfy either Neumann or Dirichlet conditions on the sides of the cell of periodicity parallel with the symmetry-plane. This is very useful from a computational point of view since the derived boundary conditions can easily be incorporated into standard numerical schemes. We also study resultant forces and moments and their variations along the rod-structure in several types of cases, even when no symmetry is required.
SPLIT DIALGEBRAS, SPLIT QUASI-JORDAN ALGEBRAS AND REGULAR ELEMENTS
Authors: VELÁSQUEZ RAÚL , FELIPE RAÚL
Published: April 2009

The notions of annihilator ideal and split structure are studied in detail for both, dialgebras and quasi-Jordan algebras. It yields methods for additional units in the two structures. As a consequence the notion of regular element receives special attention.
A GENERALIZATION OF STRONGLY GORENSTEIN PROJECTIVE MODULES
Authors: BENNIS DRISS , MAHDOU NAJIB
Published: April 2009

This paper generalize the idea of the authors in J. Pure Appl. Algebra210 (2007) 437–445. Namely, we define and study a particular case of Gorenstein projective modules. We investigate some change of rings results for this new kind of modules. Examples over not necessarily Noetherian rings are given.
Ano1 is a selective marker of interstitial cells of Cajal in the human and mouse gastrointestinal tract
Authors: Gomez-Pinilla Pedro J. , Gibbons Simon J. , Bardsley Michael R. , Lorincz Andrea , Pozo Maria J. , Pasricha Pankaj J. , de Rijn Matt Van , West Robert B. , Sarr Michael G. , Kendrick Michael L. , Cima Robert R. , Dozois Eric J. , Larson David W. , Ordog Tamas , Farrugia Gianrico
Published: April 2009

Populations of interstitial cells of Cajal (ICC) are altered in several gastrointestinal neuromuscular disorders. ICC are identified typically by ultrastructure and expression of Kit (CD117), a protein that is also expressed on mast cells. No other molecular marker currently exists to independently identify ICC. The expression of ANO1 (DOG1, TMEM16A), a Ca2+-activated Cl−channel, in gastrointestinal stromal tumors suggests it may be useful as an ICC marker. The aims of this study were therefore to determine the distribution of Ano1 immunoreactivity compared with Kit and to establish whether Ano1 is a reliable marker for human and mouse ICC. Expression of Ano1 in human and mouse stomach, small intestine, and colon was investigated by immunofluorescence labeling using antibodies to Ano1 alone and in combination with antibodies to Kit. Colocalization of immunoreactivity was demonstrated by epifluorescence and confocal microscopy. In the muscularis propria, Ano1 immunoreactivity was restricted to cells with the morphology and distribution of ICC. All Ano1-positive cells in the muscularis propria were also Kit positive. Kit-expressing mast cells were not Ano1 positive. Some non-ICC in the mucosa and submucosa of human tissues were Ano1 positive but Kit negative. A few (3.2%) Ano1-positive cells in the human gastric muscularis propria were labeled weakly for Kit. Ano1 labels all classes of ICC and represents a highly specific marker for studying the distribution of ICC in mouse and human tissues with an advantage over Kit since it does not label mast cells.
Bile acids inhibit duodenal secretin expression via orphan nuclear receptor small heterodimer partner (SHP)
Authors: Lam Ian P. Y. , Lee Leo T. O. , Choi Hueng-Sik , Alpini Gianfranco , Chow Billy K. C.
Published: April 2009

Small heterodimer partner (SHP) is an orphan nuclear receptor in which gene expression can be upregulated by bile acids. It regulates its target genes by repressing the transcriptional activities of other nuclear receptors including NeuroD, which has been shown to regulate secretin gene expression. Here, we evaluated the regulation on duodenal secretin gene expression by SHP and selected bile acids, cholic acid (CA) and chenodeoxycholic acid (CDCA). In vitro treatment of CDCA or fexaramine elevated the SHP transcript level and occupancy on secretin promoter. The increase in the SHP level, induced by bile acid treatment or overexpression, reduced secretin gene expression, whereas this gene inhibitory effect was reversed by silencing of endogenous SHP. In in vivo studies, double-immunofluorescence staining demonstrated the coexpression of secretin and SHP in mouse duodenum. Feeding mice with 1% CA-enriched rodent chow resulted in upregulation of SHP and a concomitant decrease in secretin transcript and protein levels in duodenum compared with the control group fed with normal chow. A diet enriched with 5% cholestyramine led to a decrease in SHP level and a corresponding increase in secretin expression. Overall, this study showed that bile acids via SHP inhibit duodenal secretin gene expression. Because secretin is a key hormone that stimulates bile flow in cholangiocytes, this pathway thus provides a novel means to modulate secretin-stimulated choleresis in response to intraduodenal bile acids.
Protective effect of extracellular superoxide dismutase on endothelial function during aging
Authors: Lund Donald D. , Chu Yi , Miller Jordan D. , Heistad Donald D.
Published: April 2009

Endothelial vasomotor function decreases with increasing age. Extracellular superoxide dismutase (ecSOD) protects against vascular dysfunction in several disease states. The purpose of this study was to determine whether endogenous ecSOD protects against endothelial dysfunction in old mice. Vasomotor function of the aorta was studied ex vivo in wild-type (ecSOD+/+) and ecSOD-deficient (ecSOD−/−) mice at 11 (adult) and 29 (old) mo of age. Maximal relaxation to acetylcholine (10−4 M) was impaired in vessels from adult ecSOD−/− mice [75 ± 3% (mean ± SE)] compared with wild-type mice (89 ± 2%, P < 0.05). Maximal relaxation to acetylcholine (10−4 M) was profoundly impaired in aorta from old ecSOD−/− mice (45 ± 5%) compared with wild-type mice (75 ± 4%, P < 0.05). There was a significant correlation between expression of ecSOD and maximal relaxation to acetylcholine in adult and old mice. Tempol (1 mM), a scavenger of superoxide, improved relaxation in response to acetylcholine (63 ± 8%) in old ecSOD−/− mice ( P < 0.05), but not wild-type mice (75 ± 4%). Maximal relaxation to sodium nitroprusside was similar in aorta from adult and old wild-type and ecSOD−/− mice. Quantitative RT-PCR showed a decrease in mRNA levels of ecSOD and catalase in aorta of old mice and an increase in levels of TNFα and Nox-4 in aorta of old mice compared with adult mice. The findings support the hypothesis that impaired antioxidant mechanisms may contribute to cumulative increases in oxidative stress and impaired endothelial function in old mice. In conclusion, endogenous ecSOD plays an important role in protection against endothelial dysfunction during aging.
Serum Resistin Concentrations and Risk of New Onset Heart Failure in Older Persons
Authors: Butler Javed , Kalogeropoulos Andreas , Georgiopoulou Vasiliki , de Rekeneire Nathalie , Rodondi Nicolas , Smith Andrew L. , Hoffmann Udo , Kanaya Alka , Newman Anne B. , Kritchevsky Stephen B. , Vasan Ramachandran S. , Wilson Peter W.F. , Harris Tamara B.
Published: April 2009

Objective—

Resistin is associated with inflammation and insulin resistance and exerts direct effects on myocardial cells including hypertrophy and altered contraction. We investigated the association of serum resistin concentrations with risk for incident heart failure (HF) in humans.

Methods and Results—

We studied 2902 older persons without prevalent HF (age, 73.6±2.9 years; 48.1% men; 58.8% white) enrolled in the Health, Aging, and Body Composition (Health ABC) Study. Correlation between baseline serum resistin concentrations (20.3±10.0 ng/mL) and clinical variables, biochemistry panel, markers of inflammation and insulin resistance, adipocytokines, and measures of adiposity was weak (all rho <0.25). During a median follow-up of 9.4 years, 341 participants (11.8%) developed HF. Resistin was strongly associated with risk for incident HF in Cox proportional hazards models controlling for clinical variables, biomarkers, and measures of adiposity (HR, 1.15 per 10.0 ng/mL in adjusted model; 95% CI, 1.05 to 1.27;
P
=0.003). Results were comparable across sex, race, diabetes mellitus, and prevalent and incident coronary heart disease subgroups. In participants with available left ventricular ejection fraction at HF diagnosis (265 of 341; 77.7%), association of resistin with HF risk was comparable for cases with reduced versus preserved ejection fraction.

Conclusions—

Serum resistin concentrations are independently associated with risk for incident HF in older persons.
Stimulation of Cell Surface F
1
-ATPase Activity by Apolipoprotein A-I Inhibits Endothelial Cell Apoptosis and Promotes Proliferation
Authors: Radojkovic Claudia , Genoux Annelise , Pons Véronique , Combes Guillaume , de Jonge Hugo , Champagne Eric , Rolland Corinne , Perret Bertrand , Collet Xavier , Tercé François , Martinez Laurent O.
Published: April 2009

Objectives—

Several findings argue for a protective effect of high-density lipoproteins (HDLs) against endothelial dysfunction. The molecular mechanisms underlying this protective effect are not fully understood, although recent works suggest that the actions of HDL on the endothelium are initiated by multiple interactions between HDLs (lipid or protein moiety) and cell surface receptors. We previously showed that the mitochondrial related F
1
-ATPase is a cell surface receptor for HDLs and their main atheroprotective apolipoprotein (apoA-I). Herein we test the hypothesis that the cell surface F
1
-ATPase may contribute to the ability of apoA-I and HDLs to maintain endothelial cell survival.

Methods and Results—

Cell imaging and binding assays confirmed the presence of the F
1
-ATPase at the surface of human umbilical vein endothelial cells (HUVECs) and its ability to bind apoA-I. Cell surface F
1
-ATPase activity (ATP hydrolysis into ADP) was stimulated by apoA-I and was inhibited by its specific inhibitor IF
1
-H49K. Furthermore the antiapoptotic and proliferative effects of apoA-I on HUVECs were totally blocked by the F
1
-ATPase ligands IF
1
-H49K, angiostatin and anti-βF
1
-ATPase antibody, independently of the scavenger receptor SR-BI and ABCA1.

Conclusion—

This study suggests an important contribution of cell surface F
1
-ATPase to apoA-I-mediated endothelial cell survival, which may contribute to the atheroprotective functions of apoA-I.
Activated Protein C Protects Against Myocardial Ischemia/ Reperfusion Injury via Inhibition of Apoptosis and Inflammation
Authors: Loubele Sarah T.B.G. , Spek C. Arnold , Leenders Peter , van Oerle René , Aberson Hella L. , Hamulyák Karly , Ferrell Gary , Esmon Charles T. , Spronk Henri M.H. , ten Cate Hugo
Published: April 2009

Objective—

In spite of major advances in reperfusion therapy for patients presenting with acute coronary syndrome, long-term morbidity is still substantial. A limitation of initial treatment of myocardial ischemia is the lack of prevention of ischemia/reperfusion (I/R) injury. Activated protein C (APC), a crucial mediator in the coagulation process, plays a prominent role in the crosstalk between coagulation and inflammation and provides cytoprotective effects via inhibition of apoptosis and inflammation in several human and animal studies.

Methods and Results—

APC was administered in an animal model for myocardial I/R. APC largely inhibited early myocardial I/R injury after varying reperfusion times, an effect that was absent on administration of heparin, a nonspecific anticoagulant agent. The protective effects of APC were absent in case of absence or blockade of protease activated receptor-1 (PAR-1), indicating a critical role for PAR-1 in this process. Furthermore, we showed a strong antiapoptotic effect of APC in the early phase of reperfusion combined with an antiinflammatory effect at an early stage (IL-6), as well as at a later stage (leukocyte infiltration).

Conclusions—

APC exerts strong protective effects on early myocardial I/R injury, primarily via inhibition of apoptosis and inflammation, which are regulated via PAR-1.
High-Density Lipoprotein Transport Through Aortic Endothelial Cells Involves Scavenger Receptor BI and ATP-Binding Cassette Transporter G1
Authors: Rohrer Lucia , Ohnsorg Pascale M. , Lehner Marc , Landolt Franziska , Rinninger Franz , von Eckardstein Arnold
Published: April 2009

Cholesterol efflux from macrophage foam cells is a rate-limiting step in reverse cholesterol transport. In this process cholesterol acceptors like high-density lipoproteins (HDL) and apolipoprotein (apo)A-I must cross the endothelium to get access to the donor cells in the arterial intima. Previously, we have shown that apoA-I passes a monolayer of aortic endothelial cells (ECs) from the apical to the basolateral side by transcytosis, which is modulated by the ATP-binding cassette transporter (ABC)A1. Here, we analyzed the interaction of mature HDL with ECs. ECs bind HDL in a specific and saturable manner. Both cell surface biotinylation experiments and immunofluorescence microscopy of HDL recovered ≈30% of the cell-associated HDL intracellularly. Cultivated on inserts ECs bind, internalize, and translocate HDL from the apical to the basolateral compartment in a specific and temperature-dependent manner. The size of the translocated particle was reduced, but its protein moiety remained intact. Using RNA interference, we investigated the impact of SR-BI, ABCA1, and ABCG1 on binding, internalization, and transcytosis of HDL by ECs. HDL binding was reduced by 50% and 30% after silencing of SR-BI and ABCG1, respectively, but not at all after diminishing ABCA1 expression. Knock down of SR-BI and, even more so, ABCG1 reduced HDL transcytosis but did not affect inulin permeability. Cosilencing of both proteins did not further reduce HDL binding, internalization, or transport. In conclusion, ECs transcytose HDL by mechanisms that involve either SR-BI or ABCG1 but not ABCA1.
Reduced Vessel Elasticity Alters Cardiovascular Structure and Function in Newborn Mice
Authors: Wagenseil Jessica E. , Ciliberto Chris H. , Knutsen Russell H. , Levy Marilyn A. , Kovacs Attila , Mecham Robert P.
Published: April 2009

Elastic blood vessels provide capacitance and pulse-wave dampening, which are critically important in a pulsatile circulatory system. By studying newborn mice with reduced (
Eln
+/
−
) or no (
Eln
−
/
−
) elastin, we determined the effects of altered vessel elasticity on cardiovascular development and function.
Eln
−
/
−
mice die within 72 hours of birth but are viable throughout fetal development when dramatic cardiovascular structural and hemodynamic changes occur. Thus, newborn
Eln
−
/
−
mice provide unique insight into how a closed circulatory system develops when the arteries cannot provide the elastic recoil required for normal heart function. Compared with wild type, the
Eln
−
/
−
aorta has a smaller unloaded diameter and thicker wall because of smooth muscle cell overproliferation and has greatly reduced compliance. Arteries in
Eln
−
/
−
mice are also tortuous with stenoses and dilations. Left ventricular pressure is 2-fold higher than wild type, and heart function is impaired. Newborn
Eln
+/
−
mice, in contrast, have normal heart function despite left ventricular pressures 25% higher than wild type. The major vessels have smaller unloaded diameters and longer lengths. The
Eln
+/
−
aorta has additional smooth muscle cell layers that appear in the adventitia at or just before birth. These results show that the major adaptive changes in cardiovascular hemodynamics and in vessel wall structure seen in the adult
Eln
+/
−
mouse are defined in late fetal development. Together, these results show that reduced elastin in mice leads to adaptive remodeling, whereas the complete lack of elastin leads to pathological remodeling and death.
Transient Expression of FRNK Reveals Stage-Specific Requirement for Focal Adhesion Kinase Activity in Cardiac Growth
Authors: DiMichele Laura A. , Hakim Zeenat S. , Sayers Rebecca L. , Rojas Mauricio , Schwartz Robert J. , Mack Christopher P. , Taylor Joan M.
Published: April 2009

Focal adhesion kinase (FAK) is strongly activated by integrins and growth factors and is essential for embryonic development. We previously showed that the C terminus of FAK is expressed as a separate protein termed FAK-related nonkinase (FRNK) in a smooth muscle cell–selective fashion and that FRNK functions to buffer FAK-dependent signals. We now show that FRNK is also transiently expressed in the neonatal myocardium, with peak levels occurring 5 to 7 days postnatal, just before cell cycle withdrawal. Using novel mouse models, we demonstrate that cardiac-selective expression of FRNK (leading to inhibition of FAK) starting at embryonic day 10.5 leads to a severe ventricular noncompaction defect associated with reduced cardiomyocyte proliferation. Remarkably, postnatal expression of nearly identical levels of FRNK is well tolerated and does not affect viability or anabolic cardiac growth. Nonetheless, FRNK expression in the adult heart does attenuate pathological cardiac hypertrophy following aortic banding, confirming and extending our previous data that this compensatory response is blunted in FAK null hearts. Our mechanistic studies in cultured neonatal cardiomyocytes reveal that FRNK expression induces p38/p27
kip
-dependent cell cycle withdrawal and attenuates extracellular signal-regulated kinase–dependent hypertrophic growth. These findings indicate that dynamic expression of FRNK in the neonatal heart may function to promote cardiomyocyte quiescence in an environment that is particularly rich in growth factors and growth promoting extracellular matrices.
Pretreatment With Electroacupuncture Induces Rapid Tolerance to Focal Cerebral Ischemia Through Regulation of Endocannabinoid System
Authors: Wang Qiang , Peng Ye , Chen Shaoyang , Gou Xingchun , Hu Bo , Du Juan , Lu Yan , Xiong Lize
Published: April 2009

Background and Purpose—

Our previous study demonstrated that pretreatment with electroacupuncture (EA) induces rapid tolerance to focal cerebral ischemia. The present study was aimed to investigate the involvement of the endocannabinoid system in the early neuroprotection conferred by EA pretreatment in the animal model of focal cerebral ischemia.

Methods—

Two hours after the end of EA pretreatment, focal cerebral ischemia was induced by middle cerebral artery occlusion for 120 minutes in male Sprague-Dawley rats or male C57BL/6 mice. The neurobehavioral scores, infarction volumes, and neuronal apoptosis were evaluated at 24 hours or 7 days after reperfusion in the presence or absence of AM251 (a selective cannabinoid receptor type 1 [CB1] receptor antagonist) or CB1 short interfering RNA. The expression of CB1 receptor and the content of endocannabinoids in the brains were also investigated.

Results—

EA pretreatment reduced infarct size, improved neurological outcome, and inhibited neuronal apoptosis at 24 hours or 7 days after reperfusion. The beneficial effects were abolished by AM251. CB1 knockdown by CB1 short interfering RNA attenuated EA pretreatment-induced neuroprotection. EA pretreatment upregulated the neuronal expression of CB1 receptor in the rat brains and elevated the brain tissue content of the endocannabinoid 2-arachidonylglycerol and
N
-arach-idonoylethanolamine-anandamide. Pretreatment with 2-arachidonylglycerol and
N
-arach-idonoylethanolamine-anandamide also reduced infarct size and improved neurological outcome.

Conclusion—

We conclude that pretreatment with EA increases the production of endocannabinoid 2-arachidonylglycerol and
N
-arach-idonoylethanolamine-anandamide, which elicits protective effects against transient cerebral ischemia through CB1 receptors. These results suggest a novel mechanism of EA pretreatment-induced rapid tolerance to focal cerebral ischemia.