bluuebunny/crossref_metadata_2025 huggingface dataset:
CONTROLLED LOCALIZED EIGENMODES IN PSEUDO-RANDOM MULTILAYER ELECTRON WAVEGUIDES
Authors: KOUZAEV GUENNADI A.
Published: November 2013

In this paper, the localization of eigenmodes in quasi-1-D pseudo-random potential lattice electron waveguides is studied using the equivalent circuit method applied to the Schrödinger equation. It is found that the mixed deterministic and random discrete potential and limited waveguide width allow only intermediate localization of modes, and their two main types are discovered: the gap-localized and random-lattice localized modes which are stable toward variation of the waveguide's geometry. These modes can be transformed to each other by proper choosing the waveguide parameters. The discovered and studied effects and created models are interesting in the developments of spatial nano-switches of electron waves.
ESTIMATING USER INFLUENCE IN ONLINE SOCIAL NETWORKS SUBJECT TO INFORMATION OVERLOAD
Authors: LI PEI , SUN YUNCHUAN , CHEN YINGWEN , TIAN ZHI
Published: November 2013

Online social networks have attracted remarkable attention since they provide various approaches for hundreds of millions of people to stay connected with their friends. Due to the existence of information overload, the research on diffusion dynamics in epidemiology cannot be adopted directly to that in online social networks. In this paper, we consider diffusion dynamics in online social networks subject to information overload, and model the information-processing process of a user by a queue with a batch arrival and a finite buffer. We use the average number of times a message is processed after it is generated by a given user to characterize the user influence, which is then estimated through theoretical analysis for a given network. We validate the accuracy of our estimation by simulations, and apply the results to study the impacts of different factors on the user influence. Among the observations, we find that the impact of network size on the user influence is marginal while the user influence decreases with assortativity due to information overload, which is particularly interesting.
GRAPH-VALUED INVARIANTS OF VIRTUAL AND CLASSICAL LINKS AND MINIMALITY PROBLEM
Authors: KRASNOV VLADIMIR ALEKSANDROVICH , MANTUROV VASSILY OLEGOVICH
Published: November 2013

The Kuperberg bracket is a well-known invariant of classical links. Recently, the second named author and Kauffman constructed the graph-valued generalization of the Kuperberg bracket for the case of virtual links: unlike the classical case, the invariant in the virtual case is valued in graphs which carry a significant amount of information about the virtual knot. The crucial difference between virtual knot theory and classical knot theory is the rich topology of the ambient space for virtual knots. In a paper by Chrisman and the second named author, two-component classical links with one fibered component were considered; the complement to the fibered component allows one to get highly non-trivial ambient topology for the other component. In this paper, we combine the ideas of the above mentioned papers and construct the "virtual" Kuperberg bracket for two-component links L = J ⊔ K with one component (J) fibered. We consider a new geometrical complexity for such links and establish minimality of diagrams in a strong sense. Roughly speaking, every other "diagram" of the knot in question contains the initial diagram as a subdiagram. We prove a sufficient condition for minimality in a strong sense where minimality cannot be established as introduced in the paper by Chrisman and the second named author.
UNKNOTTING RECTANGULAR DIAGRAMS OF THE TRIVIAL KNOT BY EXCHANGE MOVES
Authors: HAYASHI CHUICHIRO , YAMADA SAYAKA
Published: November 2013

If a rectangular diagram represents the trivial knot, then it can be deformed into the rectangular diagram with only two vertical edges by a finite sequence of merge operations and exchange operations, without increasing the number of vertical edges, which was shown by I. A. Dynnikov. We show in this paper that we need no merge operations to deform a rectangular diagram of the trivial knot to one with no crossings.
A B2B ARCHITECTURE AND PROTOCOL FOR RESEARCHERS COOPERATION
Authors: LLORET JAIME , TOMAS JESUS , GARCIA MIGUEL , LACUESTA RAQUEL
Published: November 2013

Some works on the researchers cooperation's literature provide the key lines for building research networks and propose new protocols and standards for business to business (B2B) data exchange, but none of them explains how researchers should contact and the procedure to select the most appropriate partner of a research enterprise, institute or university. In this paper, we propose a B2B architecture and protocol between research entities, that uses ebXML protocol. The contacts for cooperation are established based on some defined parameters and an information retrieval system. We explain the information retrieval system, the researcher selection procedure, the XML-based protocol and the workflow of our proposal. We also show the information that has to be exchanged to contact other researchers. Several simulations demonstrate that our proposal is a feasible architecture and may be used to promote the research cooperation. The main purpose of this paper is to propose an efficient procedure for searching project partners.
BSDE representations for optimal switching problems with controlled volatility
Authors: Elie Romuald , Kharroubi Idris
Published: November 2013

This paper provides two different strong BSDE representations for optimal switching problems in the case where the dynamics of the underlying diffusion process depends on the current value of the switching mode. These new representations are valid in a non-Markovian framework and make use of either one-dimensional constrained BSDEs with jumps or multidimensional BSDEs with oblique reflections, thus extending the framework considered by Hu and Tang [12]. In particular, the numerical resolution of the corresponding switching problem can therefore be treated via the entirely probabilistic schemes presented in [4] or [8].
EXTENSIONS OF HOMOGENEOUS SEMILOCAL RINGS I
Authors: EL-DEKEN SUSAN F.
Published: November 2013

A ring R with Jacobson radical J(R) is a homogeneous semilocal ring if R/J(R) is simple artinian. In this paper, we study the transfer of the property of being homogeneous semilocal from a ring R to the formal power series ring R[[x]], the skew formal power series ring R[[x, α]] and the Hurwitz series ring HR. The results of the paper generalize those proved for commutative local rings. We also consider finite centralizing extensions proving that if the ring of matrices Mn(R) is a homogeneous semilocal ring, then so is R. More generally, if e is an idempotent of a homogeneous semilocal ring S, then eSe is homogeneous semilocal.
THE ITERATION DIGRAPHS OF GROUP RINGS OVER FINITE FIELDS
Authors: WEI YANGJIANG , TANG GAOHUA , NAN JIZHU
Published: November 2013

For a finite commutative ring R and a positive integer k ≥ 2, we construct an iteration digraph G(R, k) whose vertex set is R and for which there is a directed edge from a ∈ R to b ∈ R if b = ak. In this paper, we investigate the iteration digraphs G(𝔽prCn, k) of 𝔽prCn, the group ring of a cyclic group Cn over a finite field 𝔽pr. We study the cycle structure of G(𝔽prCn, k), and explore the symmetric digraphs. Finally, we obtain necessary and sufficient conditions on 𝔽prCn and k such that G(𝔽prCn, k) is semiregular.
GENERIC JORDAN TYPE OF THE SYMMETRIC AND EXTERIOR POWERS
Authors: BENSON DAVID J. , LIM KAY JIN
Published: November 2013

We prove a result relating the stable generic Jordan types of the symmetric and exterior powers of the Heller translations of a module for a finite elementary abelian p-group. In the case of the trivial module, the stable generic Jordan types of the symmetric and exterior powers of its Heller translations are completely described.
A NEW NONLOCAL BEAM THEORY WITH THICKNESS STRETCHING EFFECT FOR NANOBEAMS
Authors: TOUNSI ABDELOUAHED , BENGUEDIAB SOUMIA , HOUARI MOHAMMED SID AHMED , SEMMAH ABDELWAHED
Published: November 2013

This paper presents a new nonlocal thickness-stretching sinusoidal shear deformation beam theory for the static and vibration of nanobeams. The present model incorporates the length scale parameter (nonlocal parameter) which can capture the small scale effect, and it accounts for both shear deformation and thickness stretching effects by a sinusoidal variation of all displacements through the thickness without using shear correction factor. Based on the nonlocal differential constitutive relations of Eringen, the equations of motion of the nanobeam are derived using Hamilton's principle. The effects of nonlocal parameter, aspect ratio and the thickness stretching on the static and dynamic responses of the nanobeam are discussed. The theoretical development presented herein may serve as a reference for nonlocal theories as applied to the bending and dynamic behaviors of complex-nanobeam-system such as complex carbon nanotube system.
miRror2.0: A PLATFORM FOR ASSESSING THE JOINT ACTION OF MICRORNAS IN CELL REGULATION
Authors: FRIEDMAN YITZHAK , LINIAL MICHAL
Published: November 2013

microRNAs (miRNAs) are short, noncoding RNAs that negatively regulate the levels of mRNA post-transcriptionally. Recent experiments revealed thousands of mRNA–miRNA pairs in which multiple miRNAs may bind the same transcript. These results raised the notion of miRNAs teamwork for a wide range of cellular context. miRror2.0 utilizes the miRNA-target predictions from over a dozen programs and resources and unifies them under a common statistical basis. The platform, called miRror2.0, considers the combinatorial regulation by miRNAs in different tissues, cell lines and under a broad range of conditions. A flexible setting permits the selection of the preferred combination of miRNA-target prediction resources as well as the statistical parameters for the analysis. miRror2.0 covers six major model organisms including human and mouse. Importantly, the system is capable of analyzing hundreds of genes that were subjected to miRNAs' regulation. Activating miRror2.0 by introducing thousands of genes from miRNA overexpression experiments successfully identified the objective miRNAs. The output from miRror2.0 is a list of genes that is optimally regulated by a defined set of miRNAs. A symmetric application of miRror2.0 starts with a set of miRNAs, and the system then seeks the preferred set of genes that are regulated by that miRNA composition. The results from miRror2.0 are empowered by an iterative procedure called PSI-miRror. PSI-miRror tests the robustness of miRror2.0 prediction. It allows a refinement of the initial list of genes in view of the miRNAs that optimally regulate this list. We present miRror2.0 as a valuable resource for supporting cellular experimentalists that seek recovery of combinatorial regulation by miRNAs from noisy experimental data. miRror2.0 is available at http://www.mirrorsuite.cs.huji.ac.il .
IN SITU UNZIPPING OF CARBON NANOTUBES TO FORM GRAPHENE NANORIBBONS
Authors: ZHOU YONG-SHENG , JIN PAN , GUO TENG , ZHU YING-CHUN , DU GAO-HUI , XU BING-SHE
Published: November 2013

We report the one step facile synthesis of graphene nanoribbons (GNRs) by unzipping carbon nanotubes (CNTs) from glucose ( C 6 H 12 O 6) precursor, using a simple chemical vapor deposition method. Some nanotubes are partially cut resulting in a GNR–CNT hybrid whereas others are fully cut to form GNRs. The average length of GNRs achieved by this method is typically in the range of 1–10 μm. The formation of GNRs is ascribed to the in situ oxygen-driven unzipping of CNTs. The process is free from aggressive oxidants and utilizes the in situ unzipping. This method offers an alternative approach for making GNRs, compared to previously used techniques to synthesize GNRs.
FABRICATION AND IN VITRO EVALUATION OF FOLATE-MODIFIED IRON FERRITE NANOPARTICLES WITH HIGH DOXORUBICIN LOADING FOR RECEPTORS-MAGNETIC-GUIDED DRUG DELIVERY
Authors: GUO LIN , DING WENCE , MENG FANDIAN
Published: November 2013

Folate-modified iron ferrite nanoparticles with high doxorubicin loading (FDMP) were developed for dual targeting of tumor cells. Large quantities of doxorubicin and folate ligand were chemically coupled to the synthesized dual-functional magnetic nanoparticles by using the multihand cross-linker poly-L-glutamic acid. FDMP exhibits high drug loading ability, narrow size distribution and pH sensitivity to drug release. The drug loading ratio and the magnetic response can be adjusted by controlling the reactant ratio. FDMP possesses high magnetic-guided ability and exhibits enhanced uptake by folate receptors expressing tumor cells and increased cancer cell cytotoxicity.
EFFECTS OF HIGH MAGNETIC FIELD ON THE STRUCTURAL EVOLUTION AND MAGNETIC PROPERTIES OF NANOCRYSTALLINE Ni FILMS
Authors: DU JIAOJIAO , LI GUOJIAN , WANG QIANG , CAO YONGZE , MA YONGHUI , HE JICHENG
Published: November 2013

This paper studies the effects of a high magnetic field on the structural evolution and magnetic properties of nanocrystalline Ni films prepared on quartz substrates by a molecular beam vapor deposition (MBVD) method. Atomic force microscope, X-ray diffractometer, transmission electron microscope and vibrating sample magnetometer were used to study the microstructures and magnetic properties of the Ni films. The results indicate that high magnetic field has no obvious influence on crystal structures except changing the lattice constant of the Ni films. However, the high magnetic field can refine particle size. The film deposited under magnetic field tends to grow through columnar mode because of the magnetized particles aligning along the direction of magnetic field. Furthermore, the ordered and dense arrangement of Ni atoms results in more spins contained in per unit volume and improves the saturation magnetization (Ms). Ms of the 6 T Ni film increases by 70% (578 emu/cm3) than that of the film without magnetic field (341 emu/cm3), and the coercivity is also slightly increased for the 6 T film.
Variable selection in near infrared spectroscopy for quantitative models of homologous analogs of cephalosporins
Authors: Feng Yan-Chun , Ni Zhen , Hu Chang-Qin
Published: November 2013

Two universal spectral ranges (4550–4100 cm-1 and 6190–5510 cm-1) for construction of quantitative models of homologous analogs of cephalosporins were proposed by evaluating the performance of five spectral ranges and their combinations, using three data sets of cephalosporins for injection, i.e., cefuroxime sodium, ceftriaxone sodium and cefoperazone sodium. Subsequently, the proposed ranges were validated by using eight calibration sets of other homologous analogs of cephalosporins for injection, namely cefmenoxime hydrochloride, ceftezole sodium, cefmetazole, cefoxitin sodium, cefotaxime sodium, cefradine, cephazolin sodium and ceftizoxime sodium. All the constructed quantitative models for the eight kinds of cephalosporins using these universal ranges could fulfill the requirements for quick quantification. After that, competitive adaptive reweighted sampling (CARS) algorithm and infrared (IR)–near infrared (NIR) two-dimensional (2D) correlation spectral analysis were used to determine the scientific basis of these two spectral ranges as the universal regions for the construction of quantitative models of cephalosporins. The CARS algorithm demonstrated that the ranges of 4550–4100 cm-1 and 6190–5510 cm-1 included some key wavenumbers which could be attributed to content changes of cephalosporins. The IR–NIR 2D spectral analysis showed that certain wavenumbers in these two regions have strong correlations to the structures of those cephalosporins that were easy to degrade.
ON A NEW DIFFERENTIAL TRANSFORMATION METHOD FOR SOLVING NONLINEAR DIFFERENTIAL EQUATIONS
Authors: Ebaid Abdelhalim
Published: November 2013

The main difficulty in solving nonlinear differential equations by the differential transformation method (DTM) is how to treat complex nonlinear terms. This method can be easily applied to simple nonlinearities, e.g. polynomials, however obstacles exist for treating complex nonlinearities. In the latter case, a technique has been recently proposed to overcome this difficulty, which is based on obtaining a differential equation satisfied by this nonlinear term and then applying the DTM to this obtained differential equation. Accordingly, if a differential equation has n-nonlinear terms, then this technique must be separately repeated for each nonlinear term, i.e. n-times, consequently a system of n-recursive relations is required. This significantly increases the computational budget. We instead propose a general symbolic formula to treat any analytic nonlinearity. The new formula can be easily applied when compared with the only other available technique. We also show that this formula has the same mathematical structure as the Adomian polynomials but with constants instead of variable components. Several nonlinear ordinary differential equations are solved to demonstrate the reliability and efficiency of the improved DTM method, which increases its applicability.
AN IMPLICIT FINITE-DIFFERENCE SOLUTION TO ONE-DIMENSIONAL COUPLED BURGERS' EQUATIONS
Authors: Srivastava Vineet K. , Awasthi Mukesh K. , Tamsir Mohammad , Singh Sarita
Published: November 2013

In this paper, an implicit finite-difference method is proposed for the numerical solutions of one-dimensional coupled nonlinear Burgers' equations on the uniform grid. The proposed Crank–Nicolson scheme forms a system of nonlinear difference equations which has to be solved at each iteration. The nonlinear assembled system of equations has been linearized by applying Newton's iteration method. The obtained linear system has been solved by using Gauss elimination with partial pivoting method. Three numerical examples have been given in order to demonstrate the accuracy and efficiency of the proposed scheme. Computed results have been compared well with the analytical solutions and those already available in the literature via the error norms.
APPLICATIONS OF KATO'S INEQUALITY TO OPERATOR-VALUED INTEGRALS ON HILBERT SPACES
Authors: Dragomir S. S.
Published: November 2013

By the use of the celebrated Kato's inequality we obtain in this paper some inequalities for operator-valued integrals on a complex Hilbert space H. Among others, we show that [Formula: see text] for any x, y ∈ H, provided [Formula: see text] and p : E → [0, ∞) are μ-measurable functions on E and such that [Formula: see text] and [Formula: see text] are Bochner integrable on E for some α ∈ [0, 1]. Natural applications for various norms and numerical radii associated with the Bochner integral of operator-valued functions and some examples for the operator exponential are presented as well.
Cytotoxicity of Magnetic Nanoparticles on Normal and Malignant Human Skin Cells
Authors: Amin Rehab M. , Abdelmonem Abuelmagd , Verwanger Thomas , Elsherbini Elsayed , Krammer Barbara
Published: November 2013

Magnetic nanoparticles have received considerable attention in nanomedicine due to their potential application as therapeutic or diagnostic tools based on their particular properties. However, prior to clinical application investigating the effect of these nanoparticles on cells is essential. The aim of the following study is therefore to evaluate the cytotoxicity of magnetic ( Fe 3 O 4) and gold-coated magnetic nanoparticles ( Fe 3 O 4@ Au ) on various cell lines in order to clarify the risk of these materials for human use. Toxicity of these nanoparticles on human dermal fibroblasts (SKIN), human squamous cell carcinoma cells (A431 cells) and human epidermal keratinocytes ( HaCaT cells) were determined using the MTT assay. Results showed that, within the used concentration range, Fe 3 O 4 nanoparticles had no significant effect on all investigated cell lines, while Fe 3 O 4@ Au nanoparticles seem to have a moderate toxicity on all cell lines with some selectivity for the malignant cells, although it is yet moderate. The different characteristic of the cell lines' survival with respect to incubation time and nanoparticle concentration could be partly due to different cell death modes. Therefore, the prepared Fe 3 O 4 nanoparticles are harmless and could be applied safely for skin cancer treatment or diagnosis.
SIMULATION ON THE PERFORMANCE OF CARBON DIOXIDE AND HYDROCARBON HEAT PUMPS FOR MODERATE TO HIGH TEMPERATURE HEATING
Authors: BAIK YOUNG-JIN , KIM MINSUNG , RA HO-SANG
Published: November 2013

In order to compare the performance of the carbon dioxide, propane and isobutane heat pumps for moderate to high temperature heating, the three heat pump cycles were optimized using a simulation method. To fairly compare the performance of the cycles by using different working fluids, each cycle was optimized from the viewpoint of heating COP by two design parameters. The first is the gas cooler (or condenser) exit temperature and the other is the ratio of the overall heat conductance of the gas cooler to the combined overall heat conductance of the gas cooler and the evaporator. The inlet and outlet temperatures of secondary fluid of the gas cooler (or condenser) were fixed at 40/90°C and 40/150°C. The heat source inlet temperature was fixed at 10°C. The flow rates of both the heat source and the heat sink were also fixed. The results shows that the hydrocarbon heat pumps have 11–17% higher heating COP than carbon dioxide heat pump under the simulation conditions considered in the present study. However, for a high temperature heating, even though the isobutane heat pump shows the best performance, the carbon dioxide heat pump looks promising due to hydrocarbon heat pumps' high compression ratio.
MAGNETIC LOGIC DEVICES FOR FUTURE COMPUTING SYSTEMS
Authors: MENG HAO , HAN GUCHANG
Published: November 2013

High performance computing system design based on complementary metal oxide semiconductor (CMOS) is facing more and more challenges due to the volatility, increased leak current and interconnection delay. Computations utilizing magnetic logic devices have attracted considerable interest as the potential alternatives because of their features of nonvolatility, re-configurability, unlimited endurance and low power consumption. Instead of using electron charges, the magnetic logic device stores and processes the data information by controlling spins, i.e., the magnetization states in a device. The emerging technologies related to the magnetic logic are mainly composed of three design schemes, i.e., the magnetoresistive logic, the magnetic quantum cellular automata and the magnetic domain wall logic. This paper will illustrate the principles as well as review the recent developments of these magnetic logic devices. Challenges and prospects of the future development are also discussed.
Sea-level variations and the quality of the continental fossil record
Authors: FARA E.
Published: November 2013

Theoretical and empirical studies suggest that sea-level change was a fundamental parameter determining the distribution of fossil marine organisms. Although a similar relationship is generally assumed for the continental fossil record, this intuition remains speculative. Quantitative evidence reveals no correlation between sea-level variations and the distribution of continental tetrapods in the Late Jurassic–Eocene interval. The quality of the continental fossil record depends on many more factors than just eustatic changes.
Map compilations and synthesis of Africa’s petroleum basins and systems
Authors: Purdy E. G. , MacGregor D. S.
Published: November 2013

The purpose of this short contribution is to provide an overview of our current state of knowledge of Africa’s petroleum systems as an introduction to the detailed volume accounts that follow. Toward that end we introduce a set of maps on a supplementary CD compiled by Purdy as part of a confidential report provided to industry subscribers some ten years ago. The maps include subsurface as well as surface structural information but, because of their vintage, have not taken account of more recent information. Nonetheless, the regional geological framework apparent on the maps has not changed and, in that sense, the maps are as relevant today as when they were first compiled. Moreover the maps serve as a useful building block on which more recently acquired exploration data can be readily added by others using facilitating computer programs.
Aptian source rocks in some South African Cretaceous basins
Authors: Van Der Spuy D.
Published: November 2013

Source rocks of the Aptian play an important role in petroleum systems operating off the west coast of Africa. Further south, Aptian source rocks are a proven component of a petroleum system described in the Bredasdorp Basin, a sub-basin of the greater Outeniqua Basin. It has been shown that these Aptian source rocks have supplied oil to the Cretaceous sands of the producing Oribi oilfield and its satellite fields. Aptian source rocks have also been intersected by numerous exploration and scientific boreholes in other sub-basins of the greater Outeniqua Basin, and off the west coast of South Africa in the Orange Basin. Data from these wells suggest the regional development of good-quality Aptian source rocks in the deeper parts of the Orange and Southern Outeniqua basins, possibly on a basin-wide scale.

In the Orange Basin, no Aptian source rocks were intersected in the boreholes drilled in the northern part of the South African sector. However, further north, in the Namibian sector of the basin, over 100 m of good-quality Aptian source rock was intersected in the Kudu wells. To the south, at about 31°S, organic carbon rich intervals a few tens of metres thick have been intersected in a number of boreholes. Here, the kerogen is largely gas-prone, with some thin intervals of shale capable of producing oil. Intersections of the Aptian in boreholes south of 32°S demonstrate how the source quality can be expected to improve from a proximal to more distal position. A thin, high total organic carbon (TOC), gas-prone interval in the most proximal position improves in quality and thickness to become up to 140 m thick, capable of generating wet gas and small amounts of oil. The Deep Sea Drilling Project (DPDS) 361 borehole, located to the southwest in the Cape Basin, intersected layered dark grey and black anoxic Aptian shales with very high TOC, with alternating marine and terrigenous influence. The hydrogen indices of over 500 mg HC/g TOC from some layers are clearly indicative of oil potential. There is thus a strong case for the regional development of a good-quality source rock within the Early Aptian succession in the deeper parts of the Orange Basin. Burial history studies show that Aptian sediments should be in the oil window in large areas to the west of the basin depocentre.

The Early Aptian source rock in the Bredasdorp Basin has been well described. Here it can be over 200 m thick and occurs over a large areal extent. The organic material is largely Type II with a Type I component. Early Aptian source rocks have also been intersected in the Pletmos Basin further to the east, where the organic-rich interval is over 80 m thick in places. There is strong seismic evidence that this source interval should be well developed in the greater Southern Outeniqua Basin to the south of these two inboard basins. Burial history studies in this large basin show that the Early Aptian interval is sufficiently mature over large areas to have generated and expelled oil.
Second and third millennium reserves development in African basins
Authors: Hemsted T.
Published: November 2013

This paper discusses the development of hydrocarbon reserves discovered onshore and offshore of the continent of Africa up to the start of the year 2000 and the future potential for new discoveries. Over 2400 hydrocarbon discoveries have been made in Africa, of which 700 were producing in significant quantities at the start of 2000. Initial recoverable reserves on these accumulations stood at 160 billion barrels of oil, 500 trillion cubic feet (TCF) gas and 12 billion barrels of condensate, with estimated cumulative production being 59 billion barrels of oil and condensate and up to 50 TCF gas. A similar proportion of the total discovered oil reserves as gas reserves have been found in cratonic basins while passive/rift basins contain more of the oil reserves than the gas reserves. Despite this mix, considerably more gas has been produced from cratonic basins than from the passive/rift basins. In the last decade, deeper-water exploration using 3-D seismic data has resulted in the discovery of significant reserves in deeper waters off West Africa and the Nile Delta. Future reserves growth is expected to be concentrated in the known petroliferous basins.
Examples of salt tectonics from West Africa: a comparative approach
Authors: Tari G. , Molnar J. , Ashton P.
Published: November 2013

Exploration experience gained in specific salt basins of West Africa may not be directly applicable to other salt basins along the entire passive margin. To conduct a comparative structural analysis, regional reflection seismic transects were constructed across the salt basins of Morocco, Senegal, Guinea-Bissau, Equatorial Guinea, Gabon and Angola.

Regional-scale similarities of the salt basins include the progressive complication of salt-related structures basinward, the change from an extensional domain on the shelf to a compressional domain on the slope and the presence of a toe-thrust front at the oceanward edge of the basins. Regional-scale differences are partly attributed to the relative stratigraphic position of the salt in relation to the rift history.

In the better-known post-rift salt basins of Equatorial Guinea, Gabon, Congo and Angola updip extension is represented by a broad rafted domain balanced by downdip contraction in the form of salt tongues, canopies and a toe-thrust zone. The efficiency of this gravity sliding/spreading across the whole margin is due to the more or less uniform original distribution of Aptian salt in the post-rift succession forming a continuous detachment level.

In contrast, the typically uneven original distribution of the Late Triassic and Early Jurassic syn-rift salt in Morocco, Mauritania, Senegal, The Gambia and Guinea-Bissau is due to basement highs separating rift half-grabens and creating a different structural pattern. Individual salt structures, such as pillows and diapirs, originated from isolated patches of the autochthonous salt. In the case of syn-rift salt, updip extension may not always be the ultimate driving force for the contractional salt-deformation downdip.
Play fairways of the Gulf of Guinea transform margin
Authors: MacGregor D. S. , Robinson J. , Spear G.
Published: November 2013

The margin between Côte d’Ivoire and the Niger Delta is a region with a common structural history, this being reflected in similarities in the stratigraphic response and play fairways identified across the region. There has been significant exploration on the narrow shelf characterizing the margin, resulting in a series of modest oil and gas discoveries. It is shown in this paper that many of the aspects of the plays in the unexplored deep-water regions of the margin are considerably more favourable to the development of giant fields than those on the shelf. This play-fairway review is based on the integration of existing publications with focused studies of multiclient 3-D seismic data over a number of areas.

Play fairways are classified by seismic sequence and trap type, with an analysis of each undertaken. The most attractive deep-water play types are: (1) anticlinal traps involving late syn-transform (Apto-Albian) and early post-transform (Late Cretaceous) reservoirs, (2) combination traps involving ponded turbidites on the shoreward flanks of these highs, and (3) stratigraphic traps associated with large Late Cretaceous submarine fan complexes. The anticlinal play is associated with the terminations of the St Paul and Romanche fracture zones, with the more recent structuring generally associated with the latter. 3-D imaging and amplitude mapping is critical to prospect delineation, particularly for the combination and stratigraphic plays. Active kitchens are evidenced involving Early and Late Cretaceous source rocks in the Côte d’Ivoire and western Ghana to Nigeria segments of the region, which are consequently upgraded. Considerable volumetric potential is indicated that promises to make the region one of significant new exploration activity in coming years.
Frasnian organic-rich shales in North Africa: regional distribution and depositional model
Authors: Lüning S. , Adamson K. , Craig J.
Published: November 2013

During the Frasnian, organic-rich shales were deposited across much of North African, most notably in parts of Morocco, Algeria, southern Tunisia, western Libya and the Western Desert of Egypt. They are estimated to be the origin of about 10% of all Palaeozoic-sourced hydrocarbons in North Africa. The depositional, palaeoecological and geochemical characteristics of this black shale unit can be best studied in the eastern Algerian Berkine (i.e. western Ghadames) Basin where the thickest and organically richest ‘hot shales’ occur. In wireline logs, the Frasnian hot shales are marked by high gamma-ray values, often in excess of 300–400 API, which, according to gamma-ray spectrometry, almost exclusively originate from an elevated uranium content. Comparison with total organic carbon (TOC) data shows that the gamma-ray curve can be used as a proxy for the TOC content of the Frasnian shales, with 150 API correlating approximately with TOCs of about 3% in eastern Algeria.

The hot shale unit usually consists of high-frequency, high-amplitude, metre-scale gammaray cycles; however, especially in the thicker hot shale units, the lower frequency envelope curve of the high-frequency gamma-ray cycles has a gradual, bell-shaped form. The gradual increase and subsequent decrease in organic richness over time may be interpreted as evidence for a gradual rise and subsequent fall of the oxygen minimum zone (OMZ), with invasion of oxygen-depleted waters onto the North African shelf. The rise of the OMZ may have been triggered by the Early Frasnian transgression, which has been described in detail from Morocco, where it is now well-dated by conodonts and is associated with characteristic black shales and carbonates. Additional high-resolution biostratigraphic data are still needed in order to better correlate the Frasnian hot shales of Algeria, Tunisia and western Libya with other Late Devonian dysaerobic/anaerobic facies in Morocco, western Egypt, Europe, South and North America.
Depression as a Risk Factor for Cancer: From Pathophysiological Advances to Treatment Implications
Authors: Currier M. Beatriz , Nemeroff Charles B.
Published: November 2013

Innate immune activation and inflammation have been posited to play a role in the pathophysiology of both depression and neoplastic growth. Cancer patients experience a threefold higher rate of depression than the general population within the first five years of diagnosis. Chronic depression is associated with increased cancer risk and shortened survival. Although the precise cellular and molecular mechanisms of this bidirectional relationship remain unclear, elevated concentrations of circulating plasma proinflammatory cytokines associated with depression may mediate the neuroendocrine, neural, and immune pathways that account for the relationship. Proinflammatory cytokines, in turn, are known to modulate key neurobiological correlates of depression including hypothalamic-pituitary-adrenal (HPA) axis dysregulation, monoamine neurotransmitter metabolism, and limbic system activity. Research is needed to determine whether optimal depression treatment improves cancer survival and to develop antidepressant strategies that target molecular and cellular mechanisms mediating inflammation and the neurobiological pathways influenced by the proinflammatory cytokines.
Using League Table Rankings in Public Policy Formation: Statistical Issues
Authors: Goldstein Harvey
Published: November 2013

This article reviews the statistical models that underpin institutional comparisons on the basis of outcome measures for their students. These multilevel models are developed to levels of complexity that match the problems posed. The strengths and limitations of inferences from these models are explored with examples taken from education.
LEPREL1 Expression in Human Hepatocellular Carcinoma and Its Suppressor Role on Cell Proliferation
Authors: Wang Jianguo , Xu Xiao , Liu Zhikun , Wei Xuyong , Zhuang Runzhou , Lu Di , Zhou Lin , Xie Haiyang , Zheng Shusen
Published: November 2013

Background. Hepatocellular carcinoma (HCC) is one of the most aggressive malignancies worldwide. It is characterized by its high invasive and metastatic potential. Leprecan-like 1 (LEPREL1) has been demonstrated to be downregulated in the HCC tissues in previous proteomics studies. The present study is aimed at a new understanding of LEPREL1 function in HCC.Methods. Quantitative RT-PCR, immunohistochemical analysis, and western blot analysis were used to evaluate the expression of LEPREL1 between the paired HCC tumor and nontumorous tissues. The biology function of LEPREL1 was investigated by Cell Counting Kit-8 (CCK8) assay and colony formation assay in HepG2 and Bel-7402 cells.Results. The levels of LEPREL1 mRNA and protein were significantly lower in the HCC tissues as compared to those of the nontumorous tissues. Reduced LEPREL1 expression was not associated with conventional clinical parameters of HCC. Overexpression of LEPREL1 in HepG2 and Bel-7402 cells inhibited cell proliferation (P<0.01) and colony formation (P<0.05). LEPREL1 suppressed tumor cell proliferation through regulation of the cell cycle by downregulation of cyclins.Conclusions. Clinical parameters analysis suggested that LEPREL1 was an independent factor in the development of HCC. The biology function experiments showed that LEPREL1 might serve as a potential tumor suppressor gene by inhibiting the HCC cell proliferation.
Analysis of Laminated Shells by Murakami’s Zig-Zag Theory and Radial Basis Functions Collocation
Authors: Maturi D. A. , Ferreira A. J. M. , Zenkour A. M. , Mashat D. S.
Published: November 2013

The static and free vibration analysis of laminated shells is performed by radial basis functions collocation, according to Murakami’s zig-zag (ZZ) function (MZZF) theory . The MZZF theory accounts for through-the-thickness deformation, by considering a ZZ evolution of the transverse displacement with the thickness coordinate. The equations of motion and the boundary conditions are obtained by Carrera’s Unified Formulation and further interpolated by collocation with radial basis functions.
A Comparison of Averaged and Full Models to Study the Third‐Body Perturbation
Authors: Solórzano Carlos Renato Huaura , Prado Antonio Fernando Bertachini de Almeida
Published: November 2013

The effects of a third‐body travelling in a circular orbit around a main body on a massless satellite that is orbiting the same main body are studied under two averaged models, single and double, where expansions of the disturbing function are made, and the full restricted circular three‐body problem. The goal is to compare the behavior of these two averaged models against the full problem for long‐term effects, in order to have some knowledge of their differences. The single averaged model eliminates the terms due to the short period of the spacecraft. The double average is taken over the mean motion of the satellite and the mean motion of the disturbing body, so removing both short period terms. As an example of the methods, an artificial satellite around the Earth perturbed by the Moon is used. A detailed study of the effects of different initial conditions in the orbit of the spacecraft is made.
Malarial Infection of Female BWF1 Lupus Mice Alters the Redox State in Kidney and Liver Tissues and Confers Protection against Lupus Nephritis
Authors: Al-Quraishy Saleh , Abdel-Maksoud Mostafa A. , El-Amir Azza , Abdel-Ghaffar Fathy A. , Badr Gamal
Published: November 2013

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease characterized by an imbalanced redox state and increased apoptosis. Tropical infections, particularly malaria, may confer protection against SLE. Oxidative stress is a hallmark of SLE. We have measured changes in the levels of nitric oxide (NO), hydrogen peroxide (H2O2), malondialdehyde (MDA), and reduced glutathione (GSH) in both kidney and liver tissues of female BWF1 lupus mice, an experimental model of SLE, after infection with either live or gamma-irradiated malaria. We observed a decrease in NO, H2O2, and MDA levels in kidney tissues after infection of lupus mice with live malaria. Similarly, the levels of NO and H2O2were significantly decreased in the liver tissues of lupus mice after infection with live malaria. Conversely, GSH levels were obviously increased in both kidney and liver tissues after infection of lupus mice with either live or gamma-irradiated malaria. Liver and kidney functions were significantly altered after infection of lupus mice with live malaria. We further investigated the ultrastructural changes and detected the number of apoptotic cells in kidney and liver tissues in situ by electron microscopy and TUNEL assays. Our data reveal that infection of lupus mice with malaria confers protection against lupus nephritis.
Increased Female MS Incidence and Differences in Gender-Specific Risk in Medium- and High-Risk Regions in Finland from 1981–2010
Authors: Holmberg Markus , Murtonen Annukka , Elovaara Irina , Sumelahti Marja-Liisa
Published: November 2013

Background. MS incidence has increased among females, suggesting the presence of environmental effect.Object. Regional differences and temporal changes in gender-specific MS incidence were studied in Finland.Methods. Cases from Jan 1, 1981 to Dec 31, 2010 in Pirkanmaa, Seinäjoki and Vaasa districts were included. The standardized incidence rates (SIR), incidences per 105person years with 95% confidence intervals (CI), and female-to-male ratios (F/M) were determined by district.Results. 1617 cases were included. Compared to Pirkanmaa, the MS risk was 1.9-fold (95% CI: 1.7–2.0) greater in Seinäjoki and 1.2-fold (95% CI: 1.1–1.4) in Vaasa, and the risk was high for both genders. The incidence trend stabilized in Seinäjoki and Vaasa, accompanied by an increase in the F/M ratio. A steady increase in Pirkanmaa was accompanied by a high F/M ratio.Conclusion. A high female preponderance accompanied a general increase in incidence since the 1990s, suggesting the influence of environmental factors. In high-risk districts, increased MS risk prevailed in both genders. High risk reflects both genetic and environmental effects. These effects may be shared with autoimmune diseases such as type 1 diabetes mellitus; the incidence of which follows MS in Finland. Population-based case-control studies are needed to identify these factor effects.
Characterization of Symmetry Properties of First Integrals for Submaximal Linearizable Third-Order ODEs
Authors: Mahomed K. S. , Momoniat E.
Published: November 2013

The relationship between first integrals of submaximal linearizable third-order ordinary differential equations (ODEs) and their symmetries is investigated. We obtain the classifying relations between the symmetries and the first integral for submaximal cases of linear third-order ODEs. It is known that the maximum Lie algebra of the first integral is achieved for the simplest equation and is four-dimensional. We show that for the other two classes they are not unique. We also obtain counting theorems of the symmetry properties of the first integrals for these classes of linear third-order ODEs. For the 5 symmetry class of linear third-order ODEs, the first integrals can have 0, 1, 2, and 3 symmetries, and for the 4 symmetry class of linear third-order ODEs, they are 0, 1, and 2 symmetries, respectively. In the case of submaximal linear higher-order ODEs, we show that their full Lie algebras can be generated by the subalgebras of certain basic integrals.
Ocular Dominance and Visual Function Testing
Authors: Lopes-Ferreira D. , Neves H. , Queiros A. , Faria-Ribeiro M. , Peixoto-de-Matos S. C. , González-Méijome J. M.
Published: November 2013

Purpose. To show the distribution of ocular dominance as measured with sensory and eye sighting methods and its potential relationship with high and low contrast LogMAR visual acuity in presbyopic subjects.Method. Forty-four presbyopes (48.5 ± 3.5 years) participated in this study. Ocular dominance was determined by eye sighting (hole-in-card) and sensorial (+1.50 D lens induced blur) methods. According to the dominance detected with each method (RE: right eye or LE: left eye), patients were classified in dominance type 1 (RE/RE), type 2 (RE/LE), type 3 (LE/RE) and type 4 (LE/LE).Results. Baseline refractive error (MSE) was RE:−0.36 ± 1.67 D and LE:−0.35 ± 1.85 D (P=0.930). RE was the dominant eye in 61.4% and 70.5% of times as obtained from sensorial and sighting methods, respectively. Most frequent dominance was of type 1 (52.3%), in this case the RE showed statistically significant better distance low contrast LogMAR VA (0.04 LogMAR units) compared to the LE (P<0.05).Conclusions. The dominance was more frequent in RE in this sample. The eye sighting and sensorial methods to define ocular dominance agreed in more than half of cases. Amount of MSE was not significantly different between dominant and non-dominant eye. But in case of right dominance, the RE presented better distance low contrast VA compared to the LE.
Finite Element Simulation of Dynamic Stability of Plane Free-Surface of a Liquid under Vertical Excitation
Authors: Kolukula Siva Srinivas , Chellapandi P.
Published: November 2013

When partially filled liquid containers are excited vertically, the plane free-surface of the liquid can be stable or unstable depending on the amplitude and frequency of the external excitation. For some combinations of amplitude and frequency, the free-surface undergoes unbounded motion leading to instability called parametric instability or parametric resonance, and, for few other combinations, the free-surface undergoes bounded stable motion. In parametric resonance, a small initial perturbation on the free-surface can build up unboundedly even for small external excitation, if the excitation acts on the tank for sufficiently long time. In this paper, the stability of the plane free-surface is investigated by numerical simulation. Stability chart for the governing Mathieu equation is plotted analytically using linear equations. Applying fully nonlinear finite element method based on nonlinear potential theory, the response of the plane free-surface is simulated for various cases.
Actin Is a Target of T-Cell Reactivity in Patients with Advanced Carotid Atherosclerotic Plaques
Authors: Profumo Elisabetta , Buttari Brigitta , Petrone Linda , Lacroce Giada , Tesori Maria Chiara , Capoano Raffaele , Salvati Bruno , Riganò Rachele
Published: November 2013

Atherosclerosis is a chronic inflammatory disease of the arterial wall associated with autoimmune reactions. In a previous study, we observed the presence of actin-specific antibodies in sera from patients with carotid atherosclerosis. To extend our previous results we evaluated the possible role of actin as antigenic target of cell-mediated immune reactions in carotid atherosclerosis. Peripheral blood mononuclear cells (PBMC) from 17 patients and 16 healthy subjects were tested by cell proliferation assay and by ELISA for cytokine production. Actin induced a proliferative response in 47% of patients’ PBMC samples, with SI ranging from 2.6 to 21.1, and in none of the healthy subjects’ samples (patients versus healthy subjects,P=0.02). The presence of diabetes in patients was significantly associated with proliferative response to actin (P=0.04). IFN-γand TNF-αconcentrations were higher in PBMC from patients than in those from healthy subjects and in PBMC proliferating to actin than in nonproliferating ones. Our data demonstrate for the first time a role of actin as a target autoantigen of cellular immune reactions in patients with carotid atherosclerosis. The preferential proinflammatory Th1 activation suggests that actin could contribute to endothelial dysfunction, tissue damage, and systemic inflammation in carotid atherosclerosis.