bluuebunny/crossref_metadata_2025 huggingface dataset:
Calibration of a Neutron Moisture Meter in Leda Clay
Authors: Burn K N
Published: April 2010

A neutron moisture meter using a scintillation detector for slow neutrons was previously calibrated in materials carefully selected to avoid inaccuracies resulting from neutron absorption. Preliminary readings of moisture density in the field using this calibration, however, were not in agreement with values obtained by auger borings. Consequently the instrument was recalibrated; in the laboratory using samples of remolded Leda clay; and in the field, by taking readings throughout a summer in the natural material. Details of moisture content and density control are described. The new calibration curve is parallel to the original one, but considerably displaced from it by what appears to be a neutron absorption effect. Chemical analyses of the clay and pore water failed to detect any elements whose capture cross-sections for neutrons are large. They did however indicate a high percentage of iron whose capture cross-section is a little larger than those for elements occurring naturally in mineral soils. Although further research is required for confirmation of this observation, results of preliminary experiments point primarily to the presence of iron in quantities large enough to explain the discrepancy between the two calibration curves.
Earthflows at the Beattie Mine Quebec, Canada
Authors: Eden W J
Published: April 2010

In June 1943 an earthflow involving more than one million cubic yards of varved clay occurred at the Beattie Mine. Subsequent remedial measures resulted in further large landslides. This paper describes the soil conditions, the sequence of events, and attempts to assess the stability of the clay slopes. It was found that the undrained analysis led to an unsafe assessment but that Terzaghi's rule for critical heights of slope gave a better indication of stability.
COMPLEX SEMANTIC NETWORKS
Authors: TEIXEIRA G. M. , AGUIAR M. S. F. , CARVALHO C. F. , DANTAS D. R. , CUNHA M. V. , MORAIS J. H. M. , PEREIRA H. B. B. , MIRANDA J. G. V.
Published: April 2010

Verbal language is a dynamic mental process. Ideas emerge by means of the selection of words from subjective and individual characteristics throughout the oral discourse. The goal of this work is to characterize the complex network of word associations that emerge from an oral discourse from a discourse topic. Because of that, concepts of associative incidence and fidelity have been elaborated and represented the probability of occurrence of pairs of words in the same sentence in the whole oral discourse. Semantic network of words associations were constructed, where the words are represented as nodes and the edges are created when the incidence-fidelity index between pairs of words exceeds a numerical limit (0.001). Twelve oral discourses were studied. The networks generated from these oral discourses present a typical behavior of complex networks and their indices were calculated and their topologies characterized. The indices of these networks obtained from each incidence-fidelity limit exhibit a critical value in which the semantic network has maximum conceptual information and minimum residual associations. Semantic networks generated by this incidence-fidelity limit depict a pattern of hierarchical classes that represent the different contexts used in the oral discourse.
FAST, PARALLEL AND SECURE CRYPTOGRAPHY ALGORITHM USING LORENZ'S ATTRACTOR
Authors: MARCO ANDERSON GONÇALVES , MARTINEZ ALEXANDRE SOUTO , BRUNO ODEMIR MARTINEZ
Published: April 2010

A novel cryptography method based on the Lorenz's attractor chaotic system is presented. The proposed algorithm is secure and fast, making it practical for general use. We introduce the chaotic operation mode, which provides an interaction among the password, message and a chaotic system. It ensures that the algorithm yields a secure codification, even if the nature of the chaotic system is known. The algorithm has been implemented in two versions: one sequential and slow and the other, parallel and fast. Our algorithm assures the integrity of the ciphertext (we know if it has been altered, which is not assured by traditional algorithms) and consequently its authenticity. Numerical experiments are presented, discussed and show the behavior of the method in terms of security and performance. The fast version of the algorithm has a performance comparable to AES, a popular cryptography program used commercially nowadays, but it is more secure, which makes it immediately suitable for general purpose cryptography applications. An internet page has been set up, which enables the readers to test the algorithm and also to try to break into the cipher.
ESTIMATING WEIGHT DISTRIBUTION IN COUPLED OSCILLATOR NETWORKS
Authors: YANG SHU-XIA , YANG ZHI-XUAN , WANG XUE-QING , BU SHOU-LIANG , JIANG I-MIN
Published: April 2010

This work proposes a method for estimating the weight distribution of a network with Gauss edge weights using a time series collected from controlled measurements of the stable dynamics of the network. Comparing the weight distribution obtained using this method with that using another scheme demonstrates that the former is effective and accurate for estimating the weight distribution P(w) of coupled oscillator networks in a broad coupling strength region. This method enables the topological properties of underlying networks to be determined from only a time series of measurements because it depends on no prior information about the dynamical system. In addition, the method is rather robust against noise.
HIERARCHICAL ORGANIZATION AND DISASSORTATIVE MIXING OF CORRELATION-BASED WEIGHTED FINANCIAL NETWORKS
Authors: CAI SHI-MIN , ZHOU YAN-BO , ZHOU TAO , ZHOU PEI-LING
Published: April 2010

Correlation-based weighted financial networks are analyzed to present cumulative distribution of strength with a power-law tail, which suggests that a small number of hub-like stocks have greater influence on the whole fluctuation of financial market than others. The relationship between clustering and connectivity of vertices emphasizes hierarchical organization, which has been depicted by minimal span tree in previous work. These results urge us to further study the mixing patter of financial network to understand the tendency for vertices to be connected to vertices that are like (or unlike) them in some way. The measurement of average nearest-neighbor degree running over classes of vertices with degree k shows a descending trend when k increases. This interesting result is first uncovered in our work, and suggests the disassortative mixing of financial network which refers to a bias in favor of connections between dissimilar vertices. All the results in weighted complex network aspect may provide some insights to deeper understand the underlying mechanism of financial market and model the evolution of financial market.
TRAFFIC FLOW AT A SIGNAL CONTROLLED T-SHAPED INTERSECTION
Authors: DING ZHONG-JUN , SUN XIAO-YAN , LIU RUN-RAN , WANG QIAO-MING , WANG BING-HONG
Published: April 2010

In this paper, traffic flow at a signal controlled T-shaped intersection with three input roads is investigated by using the cellular automata model. When each road is a double lane, the model only exists in three conflict points among three directions of flows. We introduce three-phase traffic signal and two types of signal controlling strategies, i.e. fixed signal phase order as well as adaptive signal phase order strategy, to control the traffic flow at the intersection. The phase diagram, the capacity and the average travel time of the system are investigated and compared under both strategies. The simulation results show that the traffic adaptive signal strategy is better than the fixed signal phase order strategy.
SPATIAL COHERENCE RESONANCE IN DELAYED HODGKIN–HUXLEY NEURONAL NETWORKS
Authors: WANG QING YUN , PERC MATJAŽ , DUAN ZHI SHENG , CHEN GUAN RONG
Published: April 2010

We study the phenomenon of spatial coherence resonance (SCR) on Hodgkin–Huxley (HH) neuronal networks that are characterized with information transmission delay. In particular, we examine the ability of additive Gaussian noise to optimally extract a particular spatial frequency of excitatory waves in diffusive and small-world networks on which information transmission amongst directly connected neurons is not instantaneous. On diffusively coupled HH networks, we find that for short delay lengths, there always exists an intermediate noise level by which the noise-induced spatial dynamics is maximally ordered, hence implying the possibility of SCR in the system. Importantly thereby, the noise level warranting optimally ordered excitatory waves increases linearly with the increasing delay time, suggesting that extremely long delays might nevertheless preclude the observation of SCR on diffusive networks. Moreover, we find that the small-world topology introduces another obstacle for the emergence of ordered spatial dynamics out of noise because the magnitude of SCR fades progressively as the fraction of rewired links increases, hence evidencing decoherence of noise-induced spatial dynamics on delayed small-world HH networks. Presented results thus provide insights that could facilitate the understanding of the joint impact of noise and information transmission delay on realistic neuronal networks.
QUANTITATIVE MODELING OF SPATIO-TEMPORAL DYNAMICS OF INFERIOR OLIVE NEURONS WITH A SIMPLE CONDUCTANCE-BASED MODEL
Authors: KATORI YUICHI , LANG ERIC J. , ONIZUKA MIHO , KAWATO MITSUO , AIHARA KAZUYUKI
Published: April 2010

Inferior olive (IO) neurons project to the cerebellum and contribute to motor control. They can show intriguing spatio-temporal dynamics with rhythmic and synchronized spiking. IO neurons are connected to their neighbors via gap junctions to form an electrically coupled network, and so it is considered that this coupling contributes to the characteristic dynamics of this nucleus. Here, we demonstrate that a gap junction-coupled network composed of simple conductance-based model neurons (a simplified version of a Hodgkin–Huxley type neuron) reproduce important aspects of IO activity. The simplified phenomenological model neuron facilitated the analysis of the single cell and network properties of the IO while still quantitatively reproducing the spiking patterns of complex spike activity observed by simultaneous recording in anesthetized rats. The results imply that both intrinsic bistability of each neuron and gap junction coupling among neurons play key roles in the generation of the spatio-temporal dynamics of IO neurons.
PHASE MODEL REDUCTION AND PHASE LOCKING OF COUPLED NONLINEAR OSCILLATORS
Authors: BONNIN MICHELE , CORINTO FERNANDO , GILLI MARCO
Published: April 2010

The synchronization of an oscillator with an external stimulus or between coupled elements is the subject of intense research in many areas of applied sciences. The most successful approach is based on phase modeling, founded on the idea to represent each oscillator by a phase variable. Phase models have been analyzed with a wealth of details and in a plethora of different variants, but little research has been done in view of the reduction of a physical system to the corresponding phase model. In this paper we investigate the possibility, at least within the context of analytical approximations, to obtain the phase model corresponding to a given nonlinear system. Both periodically driven and coupled oscillators are considered, and examples based on Stuart–Landau and van der Pol systems are given.
COMPLEX BEHAVIOR ANALYSIS IN QUADRATIC JERK SYSTEMS VIA FREQUENCY DOMAIN HOPF BIFURCATION
Authors: INNOCENTI G. , TESI A. , GENESIO R.
Published: April 2010

The paper deals with the characterization of Hopf bifurcations in families of third order autonomous systems involving quadratic nonlinearities. By employing Harmonic Balance (HB) tools, the set of system parameters corresponding to supercritical and subcritical bifurcations is analytically determined, together with an approximation of the actual bifurcated periodic solution. It is believed that these analytical results can be exploited in order to locate via bifurcation analysis simple systems able to display complex behaviors.
INTERACTING OSCILLATORS IN COMPLEX NETWORKS: SYNCHRONIZATION AND THE EMERGENCE OF SCALE-FREE TOPOLOGIES
Authors: ALMENDRAL J. A. , LEYVA I. , SENDIÑA-NADAL I. , BOCCALETTI S.
Published: April 2010

In natural systems, many processes can be represented as the result of the interaction of self-sustained oscillators on top of complex topological wirings of connections. We review some of the main results on the setting of collective (synchronized) behaviors in globally and locally identical coupled oscillators, and then discuss in more detail the main formalism that gives the necessary condition for the stability of a synchronous motion. Finally, we also briefly describe a case of a growing network of nonidentical oscillators, where the growth process is entirely guided by dynamical rules, and where the final synchronized state is accompanied with the emergence of a specific statistical feature (the scale-free property) in the network's degree distribution.
GENERALIZED STATISTICAL COMPLEXITY MEASURE
Authors: ROSSO OSVALDO A. , DE MICCO LUCIANA , LARRONDO HILDA A. , MARTÍN MARÍA T. , PLASTINO ANGEL
Published: April 2010

A generalized Statistical Complexity Measure (SCM) is a functional that characterizes the probability distribution P associated to the time series generated by a given dynamical system. It quantifies not only randomness but also the presence of correlational structures. We review here several fundamental issues in such a respect, namely, (a) the selection of the information measure [Formula: see text]; (b) the choice of the probability metric space and associated distance [Formula: see text]; (c) the question of defining the so-called generalized disequilibrium [Formula: see text]; (d) the adequate way of picking up the probability distribution P associated to a dynamical system or time series under study, which is indeed a fundamental problem. In this communication we show (point d) that sensible improvements in the final results can be expected if the underlying probability distribution is "extracted" via appropriate consideration regarding causal effects in the system's dynamics.
TOPOLOGICAL ANALYSIS OF COMPLEX OPTICAL TRANSPORT NETWORKS
Authors: CÁRDENAS J. P. , MOURONTE M. L. , SANTIAGO A. , FELIU V. , BENITO R. M.
Published: April 2010

SDH (Synchronous Digital Hierarchy) is the standard technology for information transmission in broadband optical networks. Unlike the Internet, SDH networks are strictly planned — rings, meshes, stars or tree-branches topologies are designed to connect their basic elements. In this work we show that the SDH network operated by Telefónica in Spain presents a power-law scaling in the degree distribution (P(k) ~ k-γ) both at the national and provincial levels. The empirically obtained scaling exponents γ are consistent with those observed in other heterogeneous complex networks. The Spanish SDH network also displays small world properties with a high clustering and short path length similar to the Internet routers network. The province subnetworks experience similar traits with regards to such properties. Considering factors such as network design policies, user demand, geographical location and types of equipment, we propose an ad hoc computational model in order to reproduce these topological properties.
CONTROL OF SYNCHRONIZATION IN COUPLED NEURAL SYSTEMS BY TIME-DELAYED FEEDBACK
Authors: HÖVEL PHILIPP , DAHLEM MARKUS A. , SCHÖLL ECKEHARD
Published: April 2010

We discuss the synchronization of coupled neurons which are modeled as FitzHugh–Nagumo systems. As smallest entity in a larger network, we focus on two diffusively coupled subsystems, which can be interpreted as two mutually interacting neural populations. Each system is prepared in the excitable regime and subject to independent random fluctuations. In order to modify their cooperative dynamics, we apply a local external stimulus in the form of an extended time-delayed feedback loop that involves multiple delays weighted by a memory parameter and investigate if the local control applied to a subsystem can allow one to steer the global cooperative dynamics. Depending on the choice of this new control parameter, we investigate different measures to quantify the influence on synchronization: ratio of interspike intervals, power spectrum, interspike interval distribution and phase synchronization intervals. We show that the control method is more robust for increasing memory parameter.
DEVELOPING A NEXT GENERATION COLONOSCOPY SIMULATOR
Authors: DE VISSER HANS , PASSENGER JOSH , CONLAN DAVID , RUSS CHRISTOPH , HELLIER DAVID , CHENG MARIO , ACOSTA OSCAR , OURSELIN SÉBASTIEN , SALVADO OLIVIER
Published: April 2010

Colonoscopy is considered the gold standard for detection and removal of precancerous polyps in the colon. Being a difficult procedure to master, exposure to a large variety of patient and pathology scenarios is crucial for gastroenterologists' training. Currently, most training is done on patients under supervision of experienced gastroenterologists. Being able to undertake a majority of training on simulators would greatly reduce patient risk and discomfort. A next generation colonoscopy simulator is currently under development, which aims to address the shortfalls of existing simulators. The simulator consists of a computer simulation of the colonoscope camera view and a haptic device that allows insertion of an instrumented colonoscope to drive the simulation and provide force feedback to the user. The simulation combines physically accurate models of the colonoscope, colon and surrounding tissues and organs with photorealistic visualization. It also includes the capability to generate randomized case scenarios where complexity of the colon physiology, pathology and environmental factors, such as colon preparation, can be tailored to suit training requirements. The long term goal is to provide a metrics based training and skill evaluation system that is not only useful for trainee instruction but can be leveraged for skills maintenance and eventual certification.
TRAINING BASED ON REAL-TIME MOTION EVALUATION FOR FUNCTIONAL REHABILITATION IN VIRTUAL ENVIRONMENT
Authors: NGUYEN VAN-HANH , MERIENNE FREDERIC , MARTINEZ JEAN-LUC
Published: April 2010

One of the most effective applications of virtual reality (VR) in physical rehabilitation is training, where patients are trained for sequence decision-making in special situations presented in virtual environment. In this application, the evaluation of the movement of the subject performing a physical task is crucial. A good evaluation of the motion is necessary to follow the progression of the patient during his training session. Therefore, it helps therapist to better supervise therapeutic planning. Actually, the performance of the patient's training is determined by subjective observation of the therapist. Our approach is to propose a system that allows the patient to perform his training and to evaluate the progress of training in an autonomous way. This system consists of a motion analysis technique for a rehabilitation application where the patient is represented by his own avatar in virtual environment. The task performance required from the patient is his capability to reproduce in real time a movement. The real-time motion evaluation technique is based on the time series data matching method called Longest Common Sub-Sequence (hereafter LCSS). It is used to calculate distance between the reference motion of virtual avatar and the captured motion data of the patients and thus is used to determine how well the patients are doing during the training. The complexity of the technique proposed is in the order of O (δ) in which δ is a constant matching window size. Our prototype application is based on Tai-chi movements which have shown many health benefits and are increasingly used for therapeutic purposes.
A HYBRID EDGE DETECTOR USING FUZZY LOGIC AND MATHEMATICAL MORPHOLOGY
Authors: KAUR AMANDEEP , SINGH CHANDAN
Published: April 2010

Edge detection concerns the localization of significant variations of the grey level image. Detection of edges in an image is very important step for a complete image understanding system. This paper proposes a new approach to edge detection which adopts fuzzy reasoning to detect edges and mathematical morphology for edge thinning. The results achieved by this algorithm are comparable to the Canny approach. In Canny edge detector we may require many runs using different combinations of the three parameters (two threshold and one sigma values) whereas in the proposed technique only one parameter needs to be set by the user coarsely to get the same results, also the computation load of Canny is higher than the proposed approach.
DETECTION OF TONGUE CRACK BASED ON DISTANT GRADIENT AND PRIOR KNOWLEDGE
Authors: YANG ZHAOHUI , LI NAIMIN
Published: April 2010

Tongue crack is an important pathological feature in traditional Chinese tongue diagnosis. However, in computerized tongue diagnosis, tongue cracks are not commonly used because the tongue crack features are hard to be accurately extracted. In this paper, we propose a new scheme for tongue crack extraction. First, for the purpose of enhancement of the tongue crack regions, we get line response image using tongue image gray-level and color information as well as the pixel distant gradient. Then tongue crack regions are extracted from line response image by methods such as hysteresis thresholding algorithm and so on. A database of 286 tongue images is established and used in our test, and the experimental results demonstrate the effectiveness of our proposed tongue crack detection method.
Regional stratigraphic architecture and reservoir types of the Oligo-Miocene deposits in the Dezful Embayment (Asmari and Pabdeh Formations) SW Iran
Authors: van Buchem F. S. P. , Allan T. L. , Laursen G. V. , Lotfpour M. , Moallemi A. , Monibi S. , Motiei H. , Pickard N. A. H. , Tahmasbi A. R. , Vedrenne V. , Vincent B.
Published: April 2010

A regional sequence stratigraphic model is proposed for the Oligo-Miocene Asmari and Pabdeh Formations in the Dezful Embayment of SW Iran. The model is based on both new detailed sedimentological observations in outcrops, core and well logs, and an improved high-resolution chronostratigraphic framework constrained by Sr isotope stratigraphy and biostratigraphy. A better understanding of the stratigraphic architecture distinguishes four, geographically separated types of Asmari reservoirs.

Three Oligocene sequences (of Rupelian, early Chattian and late Chattian age) and three Miocene sequences (of early Aquitanian, late Aquitanian and early Burdigalian age) have been distinguished, representing a period of 15.4 Ma. The stratigraphic architecture of these sequences is primarily controlled by glacio-eustatic sea-level fluctuations, which determined the distribution of carbonates, sandstones and anhydrites in this sedimentary system. Tectonic control became important in the Burdigalian with a regional tilt down towards the NE. The lithological heterogeneity, the complex geometries, and both early and late diagenetic alterations are the basis for a classification of four main stratigraphic reference types for the Asmari Reservoirs: Type 1, sandstone dominated; Type 2, mixed carbonate-siliciclastic; Type 3, mixed carbonate-anhydrite; and Type 4, carbonate dominated. The sequence stratigraphic model predicts how and when these types change laterally from one to another.
Architecture and facies differentiation within a Middle Miocene carbonate platform, Ermenek, Mut Basin, southern Turkey
Authors: Janson X. , Van Buchem F. S. P. , Dromart G. , Eichenseer H. T. , Dellamonica X. , Boichard R. , Bonnaffe F. , Eberli G.
Published: April 2010

In south-central Turkey, a carbonate platform system of early middle Miocene age is exposed in three-dimensional outcrops displaying a rich variety of carbonate facies associated with exceptionally well-preserved depositional geometries. This paper presents a detailed reconstruction of the geometries and facies organization across the prograding margin of one intra-platform carbonate bank that grew during the Langhian on the Ermenek Platform. The total thickness of the margin is approximately 250 m, and it has prograded over a distance of 1.2 km. The geometrical pattern shows an alternation between sigmoid, sigmoid-oblique, and oblique accretionary units at different scales.

Based on the facies distribution and the geometrical framework two large-scale depositional sequences and eight medium-scale depositional sequences were defined. The general evolution from a low-angle shelf geometry to a prograding flat-topped platform was associated with an evolution from oligophotic-dominated carbonate producers, such as large benthic foraminifera, molluscs, echinoderms, red algae and bryozoans at the base, to mesophotic and euphotic carbonate producer organisms, such as corals, red algae and porcellaneous small benthic foraminifera at the top. The eight medium cycles were defined primarily using the depositional geometries, since facies changes were observed only locally within these cycles. Several mechanisms influenced the stratigraphic architecture of this margin: (1) eustatic sea-level controlled the overall transgressive-regressive Langhian sequence, and two superposed large-scale sequences. Medium cycles were probably also influenced by higher frequency sea-level fluctuations; (b) climate change probably influenced the overall evolution of the faunal assemblage; and (c) antecedent topography determined the overall architecture of a shelf bordering a deeper basin.
Meteoric diagenesis in carbonates below karst unconformities: heterogeneity and control factors
Authors: Weidlich O.
Published: April 2010

The combination of sedimentological and diagenetic data is important for the characterization of carbonate pore systems. This is particularly true for carbonates that were affected by meteoric diagenesis during sub-aerial exposure, for instance at sea-level lowstands. This diagenetic environment is commonly believed to be associated with increases in porosity, permeability and pore-throat diameters. Using data from three localities, improvement or deterioration of reservoir parameters below karst unconformities were analysed with a three-fold approach. In the first step, meteoric dissolution was characterized and early to late diagenetic products were described. In the second step, sedimentological and diagenetic data were converted to petrophysical data. In the third step, modelled climate data, in particular the occurrence of monsoon cells, in conjunction with other control mechanisms, were considered to understand the processes that controlled meteoric dissolution and later pore infill.

Three case studies were analysed: (1) Lower Triassic oolites (sedimentary rocks dominated by ooids) and microbialites of the Calvörde Formation (Buntsandstein Group, Germany); (2) stacked shallowing-upward cycles of carbonate platform deposits in the Middle–Upper Triassic Mahil Formation (Arabian plate, Oman), capped by palaeosols; and (3) an Upper Triassic coral patch reef and overlying strata (Adnet, Salzburg region, Austria). Data integration allowed the establishment of three scenarios of significantly different processes related to meteoric diagenesis below unconformities: (1) increase of porosity and permeability and their preservation through time; (2) increase of porosity and permeability and subsequent pore system occlusion; and (3) decrease of porosity and permeability and creation of a barrier for pore fluids. Knowledge of the time span involved in meteoric diagenesis and the nature of the climatic regime helped to explain the origins and control mechanisms of the meteoric pore systems. The study provided evidence that a well-connected, large karst system, typical of a humid climate, is likely to be sealed subsequently by sediment and cement. Under arid climatic conditions, tight palaeosols developed at the unconformity and small karst pore systems developed which had the potential to remain open during basin evolution. Depending on the aforementioned parameters, carbonates affected by meteoric diagenesis may either become tight rocks or reservoirs.
Stratigraphic architecture and fracture-controlled dolomitization of the Cretaceous Khami and Bangestan groups: an outcrop case study, Zagros Mountains, Iran
Authors: Sharp I. , Gillespie P. , Morsalnezhad D. , Taberner C. , Karpuz R. , Vergés J. , Horbury A. , Pickard N. , Garland J. , Hunt D.
Published: April 2010

The Barremian–Aptian upper Khami Group and Albian–Campanian Bangestan Group have been studied at outcrop in Lurestan, SW Iran. The upper Khami Group comprises a thin deltaic wedge (Gadvan Fm) transgressively overlain by shelfal carbonates (Dariyan Fm). The Dariyan Fm can be divided into lower and upper units separated by a major intra-Aptian fracture-controlled karst. The top of the Daryian Fm is capped by the Arabian plate-wide Aptian–Albian unconformity. The overlying Bangestan Group includes the Kazhdumi, Sarvak, Surgah and Ilam formations. The Kazhdumi Fm represents a mixed carbonate-clastic intrashelf basin succession, and passes laterally (towards the NE) into a low-angle
Orbitolina-
dominated muddy carbonate ramp/shoal (Mauddud Mbr). The Mauddud Mbr is capped by an angular unconformity and karst of latest Albian–earliest Cenomanian age. The overlying Sarvak Fm comprises both low-angle ramp and steeper dipping (5–10°) carbonate shelf/platform systems. Three regionally extensive karst surfaces are developed in the latest Cenomanian–Turonian interval of the Sarvak Fm, and are interpreted to be related to flexure of the Arabian plate margin due to the initiation of intra-oceanic deformation. The Surgah and Ilam Fm represent clastic and muddy carbonate ramp depositional systems respectively.

Both The Khami and Bangestan groups have been affected by spectacularly exposed fracture-controlled dolomitization. Dolomite bodies are 100 m to several km in width, have plume-like geometry, with both fracture (fault/joint) and gradational diagenetic contacts with undolomitized country rock. Sheets of dolomite extend away from dolomite bodies along steeply dipping fault/joint zones, and as strata-bound bodies preferentially following specific depositional/diagenetic facies or stratal surfaces. There is a close link between primary depositional architecture/facies and secondary dolomitization. Vertical barriers to dolomitization are low permeability mudstones, below which dolomitizing fluids moved laterally. Where these barriers are cut by faults and fracture corridors, dolomitization can be observed to have advanced upwards, indicating that faults and joints were fluid migration conduits.

Comparisons to Jurassic–Cenozoic dolomites elsewhere in Iran, Palaeozoic dolomites of North America and Neogene dolomites of the Gulf of Suez indicate striking textural, paragenetic and outcrop-scale similarities. These data imply a common fracture-controlled dolomitization process is applicable regardless of tectonic setting (compressional, transtensional and extensional).
Depositional sequences and palynology of Triassic carbonate-evaporite platform deposits in the Palmyrides, Syria
Authors: Lučić D. , Ivkoviċ Z. , Foršek G. , Takač D. , Bubniċ J. , Koch G.
Published: April 2010

This paper describes the results of new stratigraphic correlations and petroleum systems analyses of the Triassic deposits in the Syrian Palmyrides. The correlations are based on well data and new palynological work which reconcile previous lithological and stratigraphic miscorrelations of Triassic sequences from this region. The sequences are subdivided into four Megacycles, which are directly related to the key elements of the petroleum systems of the Palmyrides. The hydrocarbon discoveries within these systems, the fluid contacts and hydrodynamics are explained with reference to the Megacycle subdivision. This subdivision is applied on a regional scale and is used to define the distribution of reservoir seal pairs for volumetric estimations.
Sequence stratigraphy of Cenomanian–Turonian carbonate platform margins (Sarvak Formation) in the High Zagros, SW Iran: an outcrop reference model for the Arabian Plate
Authors: Razin P. , Taati F. , van Buchem F. S. P.
Published: April 2010

A high resolution sequence stratigraphic model has been constructed for the mid-Cretaceous Sarvak Formation (in the High Zagros region of SW Iran) which was deposited close to the eastern margin of the Arabian Plate. The exceptional outcrop quality, displaying the detailed facies patterns in the transition zone from carbonate platform to intra-shelf basin, offers the rare opportunity to distinguish between the relative control of carbonate sediment supply (S) and accommodation (A) on the depositional geometries of third- and fourth-order depositional sequences.

Four third-order sequences have been distinguished in the Sarvak Formation, with a duration varying between 1.5 and 3 Ma, and a thickness of 50–150 m. These are in turn composed of fourth- and fifth-order sequences that form the stratigraphic building blocks of this carbonate system. A significant distinction has been made in the third-order sequences between the early transgression (e-TST) when the system was still flat, and corresponds to a ramp setting, and the late transgression (l-TST) when the carbonate platform to intra-shelf basin topography was created. The rate of accommodation creation is identified as the dominant factor controlling the morphology of the depositional profile, and, as such, the driving motor behind the dynamics of this type of carbonate system. The dip angle of the depositional profile has a major influence on: (1) the hydrodynamics of the system; (2) the type of carbonate sediment; and (3) the volume of carbonate sediment produced. A good correlation with the third-order sequences of the Natih Formation in Oman is demonstrated, which supports a dominant control by eustatic sea-level changes and a similar response of the carbonate system to changes in the rate of sea-level rise on the southern part of the Arabian Plate.

This outcrop analogue can be considered as a good reference model for the Cenomanian–Turonian carbonate platform margins of the Arabian Plate, but also as a textbook example of the response of carbonate systems to sea-level fluctuations (relative influence of accommodation and sediment supply).
Normal targeting of a tagged Kv1.5 channel acutely transfected into fresh adult cardiac myocytes by a biolistic method
Authors: Dou Ying , Balse Elise , Dehghani Zadeh Alireza , Wang Tiantian , Goonasekara Charitha L. , Noble Geoffrey P. , Eldstrom Jodene , Steele David F. , Hatem Stéphane N. , Fedida David
Published: April 2010

The transfection of cardiac myocytes is difficult, and so most of the data regarding the regulation of trafficking and targeting of cardiac ion channels have been obtained using heterologous expression systems. Here we apply the fast biolistic transfection procedure to adult cardiomyocytes to show that biolistically introduced exogenous voltage-gated potassium channel, Kv1.5, is functional and, like endogenous Kv1.5, localizes to the intercalated disc, where it is expressed at the surface of that structure. Transfection efficiency averages 28.2 ± 5.7% of surviving myocytes at 24 h postbombardment. Ventricular myocytes transfected with a tagged Kv1.5 exhibit an increased sustained current component that is ∼40% sensitive to 100 μM 4-aminopyridine and which is absent in myocytes transfected with a fluorescent protein-encoding construct alone. Kv1.5 deletion mutations known to reduce the surface expression of the channel in heterologous cells similarly reduce the surface expression in transfected ventricular myocytes, although targeting to the intercalated disc per se is generally unaffected by both NH2- and COOH-terminal deletion mutants. Expressed current levels in wild-type Kv1.5, Kv1.5ΔSH3( 1 ), Kv1.5ΔN209, and Kv1.5ΔN135 mutants were well correlated with apparent surface expression of the channel at the intercalated disc. Our results conclusively demonstrate functionality of channels present at the intercalated disc in native myocytes and identify determinants of trafficking and surface targeting in intact cells. Clearly, biolistic transfection of adult cardiac myocytes will be a valuable method to study the regulation of surface expression of channels in their native environment.
Neuronal death during combined intermittent hypoxia/hypercapnia is due to mitochondrial dysfunction
Authors: Douglas Robert M. , Ryu Julie , Kanaan Amjad , del Carmen Rivero Maria , Dugan Laura L. , Haddad Gabriel G. , Ali Sameh S.
Published: April 2010

Breathing-disordered states, such as in obstructive sleep apnea, which are cyclical in nature, have been postulated to induce neurocognitive morbidity in both pediatric and adult populations. The oscillatory nature of intermittent hypoxia, especially when chronic, may mimic the paradigm of ischemia-reperfusion in that tissues and cells are exposed to episodes of low and high O2 and this may lead to oxidant stress. Therefore, we decided to explore the potential contribution of oxidant stress in our intermittent hypoxia/hypercapnia animal model and the role that mitochondria might play in this stress. Neonatal mice were exposed to intermittent hypoxia/hypercapnia for 10 days and 2 wk. Combined intermittent hypoxia/hypercapnia led to a marked increase in apoptotic cell death in the cerebral cortex. Oxygen consumption studies in isolated mitochondria from intermittent hypoxia/hypercapnia-exposed brains demonstrated significant reductions in both state 4 and state 3 respiratory activities by ∼60% and 75%, respectively. Electron paramagnetic resonance spectroscopy registered a significant increase in superoxide production during nonphosphorylating state 4 by 37%, although superoxide leakage during state 3 did not increase upon treatment. Neuronal superoxide-specific dihydroethidium oxidation was also greater in exposed animals. These studies indicate that intermittent hypoxia/hypercapnia leads to oxidative stress due to mitochondrial response within the mouse central nervous system.
Dysregulation of l-arginine metabolism and bioavailability associated to free plasma heme
Authors: Omodeo-Salè F. , Cortelezzi L. , Vommaro Z. , Scaccabarozzi D. , Dondorp A. M.
Published: April 2010

Severe Plasmodium falciparum malaria is associated with hypoargininemia, which contributes to impaired systemic and pulmonary nitric oxide (NO) production and endothelial dysfunction. Since intravascular hemolysis is an intrinsic feature of severe malaria, we investigated whether and by which mechanisms free heme [Fe(III)-protoporphyrin IX (FP)] might contribute to the dysregulation of l-arginine (l-Arg) metabolism and bioavailability. Carrier systems “y+” [or cationic amino acid transporter (CAT)] and “y+L” transport l-Arg into red blood cells (RBC), where it is hydrolyzed to ornithine and urea by arginase (isoform I) or converted to NO· and citrulline by endothelial nitric oxide synthase (eNOS). Our results show a significant and dose-dependent impairment of l-Arg transport into RBC pretreated with FP, with a strong inhibition of the system carrier y+L. Despite the impaired l-Arg influx, higher amounts of l-Arg-derived urea are produced by RBC preexposed to FP caused by activation of RBC arginase I. This activation appeared not to be mediated by oxidative modifications of the enzyme. We conclude that l-Arg transport across RBC membrane is impaired and arginase-mediated l-Arg consumption enhanced by free heme. This could contribute to reduced NO production in severe malaria.
An essential role of PDCD4 in vascular smooth muscle cell apoptosis and proliferation: implications for vascular disease
Authors: Liu Xiaojun , Cheng Yunhui , Yang Jian , Krall Thomas J. , Huo Yuqing , Zhang Chunxiang
Published: April 2010

It is well established that vascular smooth muscle cell (VSMC) apoptosis and proliferation are critical cellular events in a variety of human vascular diseases. However, the molecular mechanisms involved in controlling VSMC apoptosis and proliferation are still unclear. In the current study, we have found that programmed cell death 4 (PDCD4) is significantly downregulated in balloon-injured rat carotid arteries in vivo and in platelet-derived growth factor-stimulated VSMCs in vitro. Overexpression of PDCD4 via adenovirus (Ad-PDCD4) increases VSMC apoptosis in an apoptotic model induced by serum deprivation. In contrast, VSMC apoptosis is significantly decreased by knockdown of PDCD4 via its small interfering RNA. In the rat carotid arteries in vivo, VSMC apoptosis is increased by Ad-PDCD4. We have further identified that activator protein 1 is a downstream signaling molecule of PDCD4 that is associated with PDCD4-mediated effects on VSMC apoptosis. In addition, VSMC proliferation was inhibited by overexpression of PDCD4. The current study has identified, for the first time, that PDCD4 is an essential regulator of VSMC apoptosis and proliferation. The downregulation of PDCD4 expression in diseased vascular walls may be responsible for the imbalance of VSMC proliferation and apoptosis. The results indicate that PDCD4 may be a new therapeutic target in proliferative vascular diseases.
Physical (in)activity-dependent alterations at the rostral ventrolateral medulla: influence on sympathetic nervous system regulation
Authors: Mueller Patrick J.
Published: April 2010

A sedentary lifestyle is a major risk factor for cardiovascular disease, and rates of inactivity and cardiovascular disease are highly prevalent in our society. Cardiovascular disease is often associated with overactivity of the sympathetic nervous system, which has both direct and indirect effects on multiple organ systems. Although it has been known for some time that exercise positively affects the brain in terms of memory and cognition, only recently have changes in how the brain regulates the cardiovascular system been examined in terms of physical activity and inactivity. This brief review will discuss the evidence for physical activity-dependent neuroplasticity related to control of sympathetic outflow. It will focus particularly on recent studies from our laboratory and others that have examined changes that occur in the rostral ventrolateral medulla (RVLM), considered one of the primary brain regions involved in the regulation and generation of sympathetic nervous system activity.
Phosphaturic action of fibroblast growth factor 23 in Npt2 null mice
Authors: Tomoe Yuka , Segawa Hiroko , Shiozawa Kazuyo , Kaneko Ichiro , Tominaga Rieko , Hanabusa Etsuyo , Aranami Fumito , Furutani Junya , Kuwahara Shoji , Tatsumi Sawako , Matsumoto Mitsutu , Ito Mikiko , Miyamoto Ken-ichi
Published: April 2010

In the present study, we evaluated the roles of type II and type III sodium-dependent Pi cotransporters in fibroblast growth factor 23 (FGF23) activity by administering a vector encoding FGF23 with the R179Q mutation (FGF23M) to wild-type (WT) mice, Npt2a knockout (KO) mice, Npt2c KO mice, and Npt2a−/−Npt2c−/− mice (DKO mice). In Npt2a KO mice, FGF23M induced severe hypophosphatemia and markedly decreased the levels of Npt2c, type III Na-dependent Pi transporter (PiT2) protein, and renal Na/Pi transport activity. In contrast, in Npt2c KO mice, FGF23M decreased plasma phosphate levels comparable to those in FGF23M-injected WT mice. In DKO mice with severe hypophosphatemia, FGF23M administration did not induce an additional increase in urinary phosphate excretion. FGF23 administration significantly decreased intestinal Npt2b protein levels in WT mice but had no effect in Npt2a, Npt2c, and DKO mice, despite marked suppression of plasma 1,25(OH)2D3 levels in all the mutant mice. The main findings were as follow: 1) FGF23-dependent phosphaturic activity in Npt2a KO mice is dependent on renal Npt2c and PiT-2 protein; 2) in DKO mice, renal Pi reabsorption is not further decreased by FGF23M, but renal vitamin D synthesis is suppressed; and 3) downregulation of intestinal Npt2b may be mediated by a factor(s) other than 1,25(OH)2D3. These findings suggest that Npt2a, Npt2c, and PiT-2 are necessary for the phosphaturic activity of FGF23. Thus complementary regulation of Npt2 family proteins may be involved in systemic Pi homeostasis.
Decrease in dietary K intake stimulates the generation of superoxide anions in the kidney and inhibits K secretory channels in the CCD
Authors: Wang Zhi-Jian , Sun Peng , Xing WenMing , Pan ChunYang , Lin Dao-Hong , Wang Wen-Hui
Published: April 2010

We previously demonstrated that K depletion inhibited ROMK-like small-conductance K channels (SK) in the cortical collecting duct (CCD) and that the effect was mediated by superoxide anions that stimulated Src family protein tyrosine kinase (PTK) and mitogen-activated protein kinase (MAPK) ( 51 ). However, because animals on a K-deficient diet had a severe hypokalemia, superoxide-dependent signaling may not regulate ROMK channels under physiological conditions with a normal plasma K concentration. In the present study, we used the patch-clamp technique and Western blot to examine the effect of a moderate K restriction on ROMK-like SK channels and the role of PTK and MAPK in regulating apical K channels in the CCD of animals on a low-K diet (LK; 0.1% K). Rats and mice fed a LK diet for 7 days had a normal plasma K concentration. However, a LK intake increased the expression of angiotensin II type 1 receptor in the kidney. Moreover, patch-clamp experiments demonstrated that LK intake decreased the probability finding SK channels and channel activity defined by NPo (a product of channel number and open probability) in the CCD of both rat and mouse kidneys. Also, LK intake significantly stimulated the production of superoxide anions in the renal cortex and outer medulla in both rats and mice and increased superoxide level in the rat CCD. Moreover, LK intake augments the phosphorylation of p38 and ERK MAPK, the expression of c-Src and tyrosine phosphorylation of ROMK channels. However, treatment of animals with tempol abolished the effect of LK intake on MAPK and c-Src and increased ROMK channel activity in comparing with those of nontreated rats on a LK diet. Inhibiting p38 and ERK with SB202190 and PD98059 significantly stimulated SK in the CCD in rats on a LK diet. In addition, inhibition of PTK with herbimycin A activated SK channels in the CCD from rats on a LK diet. We conclude that LK intake stimulates the generation of superoxide anion and related products and that MAPK and Src family PTK play a physiological role in inhibiting apical K channels in the principal cells in response to LK intake.