bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Light on the Alkaline Phosphatase Activity ofSelenastrum capricornutum(Chlorophyceae) in Streams
Authors: Klotz R. L.
Published: November 2008

The alkaline phosphatase activity (APA) of Selenastrum capricomutum Printz incubated in situ in four streams in New York State was inversely related to total insolation. APA was not correlated with stream molybdate reactive phosphorus over the range of concentrations encountered. Selenastrum showed no diel cycle of APA. The phosphorus fraction made available by the activity of alkaline phosphatases, enzyme hydrolyzable phosphorus (measured for the first time in streams), increased the phosphorus supply to organisms with high APA.
The Human Factor in Fishery Resource Management
Authors: Pringle J. D.
Published: November 2008

Scientists working within a geographic area require a forum where the scientific basis of resource management plans can be vetted. Good science then only becomes good management if the management plan or regulations are accepted by fishermen. Scientists and managers frequently assume that fishermen oppose resource management when the latter disregards a management plan developed without consultation or presented in an unclear manner. I show that certain eastern Canadian and Californian inshore fishermen have a positive concern for resource management, and that management plans can be successfully developed within a consultative process. Scientists and managers must present new concepts and resource-based science to their clients (the fishermen) in a lucid fashion. Once a mutual understanding is developed, good resource management can follow.
MULTIPARTY CONTROLLED DETERMINISTIC SECURE QUANTUM COMMUNICATION THROUGH ENTANGLEMENT SWAPPING
Authors: DONG LI , XIU XIAO-MING , GAO YA-JUN , CHI FENG
Published: November 2008

A three-party controlled deterministic secure quantum communication scheme through entanglement swapping is proposed firstly. In the scheme, the sender needs to prepare a class of Greenberger–Horne–Zeilinger (GHZ) states which are used as quantum channel. The two communicators may securely communicate under the control of the controller if the quantum channel is safe. The roles of the sender, the receiver, and the controller can be exchanged owing to the symmetry of the quantum channel. Different from other controlled quantum secure communication schemes, the scheme needs lesser additional classical information for transferring secret information. Finally, it is generalized to a multiparty controlled deterministic secure quantum communication scheme.
CELL-TO-SITE RENORMALIZATION GROUP STUDY OF A SANDPILE
Authors: CHENG AN-CHUNG , CHEN CHIEN-FU , LIN CHAI-YU
Published: November 2008

This study investigates the Bak–Tang–Wiesenfeld sandpile using a renormalization group (RG) approach based on the similarity of L × L RG cells of different scales. The fundamental difficulty of this approach arises from the lack of full enumeration of all relaxations inside a RG cell as L ≥ 3. This study develops a simple sampling algorithm to sample the relaxations and applies this algorithm to the RG calculations for L = 3, 4, and 8. As the fixed point analysis shows, increasing L does not lead the resultant height probabilities toward the exact solution.
TRAFFIC DYNAMICS IN A TWO-LANE MIXED TRAFFIC SYSTEM: EFFECT OF FOUR LANE CHANGING REGULATIONS
Authors: ZHANG WEI-WEI , JIANG RUI , YUAN YAO-MING , WU QING-SONG
Published: November 2008

This paper investigates traffic dynamics of two-lane mixed traffic flow system composed of cars and buses, which are characterized by different lengths and different maximum velocities. Four lane changing regulations are studied, which reveals effect of lane changing ban, symmetric and asymmetric lane changing rules on traffic flow characteristics (flow rate, carry capability, lane changing frequency, and lane usage). We expect that our results could be useful for traffic management.
EXTENDED FIBER BUNDLE MODEL FOR TRAFFIC JAMS ON SCALE-FREE NETWORKS
Authors: ZHENG JIAN-FENG , GAO ZI-YOU , ZHAO XIAO-MEI , FU BAI-BAI
Published: November 2008

In this paper, we extend a fiber bundle model to study the propagation of traffic jams on scale-free networks. For the special distributions of traffic handling capacities of the links and traffic load on the nodes, the critical behavior of the jamming transition on scale-free networks is studied analytically. It is found that the links connecting to the nodes with larger degrees are more prone to suffering from traffic jams. This feature is associated with a propagation that follows a precise hierarchical dynamics. Finally, the average failure rate of the networks, which is defined as the fraction of total broken links of the network, is investigated analytically and by simulations in scale-free networks. We mainly find that, when β > γ (β and γ are the scaling exponents of the load distribution and degree distribution, respectively), there is a scaling between the average failure rate of the scale-free networks 1 - G and the network size N, 1 - G ~ N-1, independent of γ.
SPLITTING LANDAU LEVELS ON THE 2D TORUS BY PERIODIC PERTURBATIONS
Authors: ONOFRI E.
Published: November 2008

We study the spectrum of the Schroedinger operator for a particle constrained on a two-dimensional flat torus under the combined action of a transverse magnetic field and a conservative force. A numerical method is presented which allows to compute the spectrum with high accuracy. The method employs a fast Fourier transform to accurately represent the momentum variables and takes into account the twisted boundary conditions required by the presence of the magnetic field. An accuracy of 12 digits is attained even with coarse grids. Landau levels are reproduced in the case of a uniform magnetic field satisfying Dirac's condition. A new fine structure of levels within the single Landau level is formed when the field has a sinusoidal component with period commensurable to the integer magnetic charge. This fact is interpreted in terms of the peculiar symmetry ZN × ZN which holds in the unperturbed case.
LATE TIME ACCELERATION IN 3-BRANE BRANS–DICKE COSMOLOGY
Authors: ERRAHMANI A. , OUALI T.
Published: November 2008

In order to investigate more features of the Brans–Dicke cosmology in the five-dimensional spacetime, we explore the solutions of its dynamical systems. A behavior of the universe in its early and late time by means of the scale factor is considered. As a result, we show that it is possible to avoid the big rip singularity and to cross the phantom divide line. Furthermore, we review the dark energy component of the universe and its agreement with the observation data for this 3-brane Brans–Dicke cosmology by means of the cosmological parameters.
WIRES WITH QUANTUM MEMORY
Authors: CHRYSSOMALAKOS C. , GELBWASER-KLIMOVSKY D. , HERNANDEZ H. , OKON E.
Published: November 2008

We show that quantum particles constrained to move along curves undergoing cyclic deformations acquire, in general, geometric phases. We treat explicitly an example, involving particular deformations of a circle, and ponder on potential applications.
NEW AGEGRAPHIC DARK ENERGY MODEL WITH GENERALIZED UNCERTAINTY PRINCIPLE
Authors: KIM YONG-WAN , LEE HYUNG WON , MYUNG YUN SOO , PARK MU-IN
Published: November 2008

We investigate the new agegraphic dark energy models with generalized uncertainty principle (GUP). It turns out that although the GUP affects the early universe, it does not change the current and future dark energy-dominated universe significantly. Furthermore, this model could describe the matter-dominated universe in the past only when the parameter n is chosen to be n > n c , where the critical value is determined to be n c = 2.799531478.
A NONLINEAR DYNAMICS PERSPECTIVE OF WOLFRAM'S NEW KIND OF SCIENCE PART IX: QUASI-ERGODICITY
Authors: CHUA LEON O. , PAZIENZA GIOVANNI EGIDIO , ORZO LASZLO , SBITNEV VALERY I. , SHIN JINWOOK
Published: November 2008

Our scientific odyssey through the theory of 1-D cellular automata is enriched by the definition of quasi-ergodicity, a new empirical property discovered by analyzing the time-1 return maps of local rules. Quasi-ergodicity plays a key role in the classification of rules into six groups: in fact, it is an exclusive characteristic of complex and hyper Bernoulli-shift rules. Besides introducing quasi-ergodicity, this paper answers several questions posed in the previous chapters of our quest. To start with, we offer a rigorous explanation of the fractal behavior of the time-1 characteristic functions, finding the equations that describe this phenomenon. Then, we propose a classification of rules according to the presence of Isles of Eden, and prove that only 28 local rules out of 256 do not have any of them; this result sheds light on the importance of Isles of Eden. A section of this paper is devoted to the characterization of Bernoulli basin-tree diagrams through modular arithmetic; the formulas obtained allow us to shorten drastically the number of cases to take into consideration during numerical simulations. Last but not least, we present some theorems about additive rules, including an analytical explanation of their scale-free property.
RENEWAL AGING IN NON-HOMOGENEOUS POISSON PROCESSES WITH PERIODIC RATE MODULATION
Authors: PARADISI PAOLO , GRIGOLINI PAOLO , BIANCO SIMONE , AKIN OSMAN C.
Published: November 2008

The statistical properties of sequences of Waiting Times generated by Non-Homogeneous Poisson Processes are investigated by means of Renewal Aging, i.e. a statistical analysis being able to detect the presence of genuine renewal events with non-Poisson statistics. The Renewal Aging features of two non-homogeneous Poisson models with different prescriptions of the rate modulation are compared. Both prescriptions are essentially periodic. In the first model, the rate is a totally deterministic and smooth harmonic function. In the second model, the rate modulation is deterministic and smooth almost everywhere, except in some singular points occurring with a periodicity affected by weak random fluctuations.

The main parameter of both models is the modulation speed, defined as the ratio between the modulation period and the average Waiting Time. This allows to distinguish between slow, intermediate and fast modulation of the rate. As expected, in the very slow modulation case both models have a strongly reduced Renewal Aging, practically zero, because the analysis is affected by local clusters of Waiting Times with the same Poisson rate. In the intermediate range of modulation speeds, both models show non-zero Renewal Aging and the behavior of the two models tends to be more different as the modulation speed decreases.

Going towards the fast modulation regime, the behavior of the two models becomes completely different from one another. Model I does not show a definite global Renewal Aging. On the time scale of the modulation period, local oscillations arise in the Probability Density Function and an apparent oscillating aging is also observed. However, this form of aging is not the manifestation of genuine renewal non-Poisson events, but it is related to the local oscillations. On the contrary, Model II displays Renewal Aging features in agreement with a homogeneous Renewal non-Poisson Process. It is argued that this is related to the singular points in the rate modulation of Model II, which, due to their random occurrence, could be identified with genuine critical non-Poisson events. The approach presented here could have interesting applications in problems involving dichotomous noise and, in particular, in the statistical characterization of ON–OFF fluorescence intermittency experimentally observed in complex systems, such as nano-crystals and single bio-molecules stimulated by laser fields.
RAY CHAOS IN UNDERWATER ACOUSTIC WAVEGUIDES
Authors: VIROVLYANSKY A. L.
Published: November 2008

The chaotic motion of a ray path in a deep water acoustic waveguide with internal-wave-induced fluctuations of the sound speed is investigated. A statistical approach for the description of chaotic rays is discussed. The behavior of ray trajectories is studied using Hamiltonian formalism expressed in terms of action-angle variables. It is shown that the range dependence of the action variable of chaotic ray can be approximated by a random Wiener process. On the basis of this result, analytical expressions for probability density functions of ray parameters are derived. Distributions of coordinates, momenta (grazing angles), and actions of sound rays are evaluated. Numerical simulation shows that statistical characteristics of ray parameters weakly depend on a particular realization of random perturbation giving rise to ray chaos.
TRANSITION TO CHAOS FROM QUASIPERIODIC MOTIONS ON A FOUR-DIMENSIONAL TORUS PERTURBED BY EXTERNAL NOISE
Authors: ANISHCHENKO V. S. , NIKOLAEV S. M.
Published: November 2008

We propose a new autonomous dynamical system of dimension N = 4 that demonstrates the regime of stable two-frequency motions. It is shown that the system of two generators of quasiperiodic oscillations with symmetric coupling can realize motions on four-dimensional torus with resonant structures on it in the form of three- and two-dimensional torus. We show that with increase of noise intensity when the dimension of torus is higher it is destroyed faster.
WORKING MEMORY IN THE NETWORK OF NEURON-LIKE UNITS WITH NOISE
Authors: KLINSHOV V. V. , NEKORKIN V. I.
Published: November 2008

A model of working memory system in the form of a network of neuron-like units is considered. The units are stimulated by a periodic subthreshold stimulus and interact via inhibitory feedback. The information storage in the system occurs in the form of periodic clusters of neural activity. Several sequentially firing clusters can coexist in the network simultaneously corresponding to several stored images. The influence of noise on cluster dynamics and noise resistance of the system are studied. Optimal parameters corresponding to maximal noise resistance of the system were found.
ON THE STATISTICAL EXPONENTIATION METHOD IN CUMULANT ANALYSIS OF QUASIDETERMINISTIC SIGNALS
Authors: GAVRILIN A. T.
Published: November 2008

In this article we derive rough formulas for the probability distribution functions of sampled higher-order spectra of poly-harmonic signals corrupted by Gaussian noise. These formulas provide a basis for analyzing the performance detection algorithms for finite-sample length.
SLOW DIFFUSION ON THE SURFACE WITH EQUAL POTENTIAL WELLS
Authors: CHICHIGINA O. A. , ROMANOVSKY YU. M. , SCHIMANSKY-GEIER LUTZ
Published: November 2008

The diffusion process on the surface with equivalent potential wells is investigated. These wells are considered deep enough to keep the particle for longer than the correlation time. The quasi-equilibrium Boltzmann distribution is applied inside the well to calculate the escape time. This time characterizes jumps from a well to another one. The coefficient of such a diffusion is calculated as a function of temperature, shape, depth and localization of potential wells and the mass of the particles.
INVESTIGATION OF STOCHASTIC RESONANCE IN MONOSTABLE SYSTEMS
Authors: AGUDOV N. V. , KRICHIGIN A. V.
Published: November 2008

The phenomena of stochastic resonance is studied in overdamped nonlinear monostable systems driven by a periodic signal and Gaussian white noise. It is shown that the signal power amplification as a function of input noise intensity can be different depending on nonlinearity: it can monotonically grow, decrease and it can reach a maximum at certain value of the noise intensity. Nevertheless, the output signal to noise ratio is shown to be always a decreasing function of input noise intensity.
RELATIVE KOLMOGOROV ENTROPY OF A CHAOTIC SYSTEM IN THE PRESENCE OF NOISE
Authors: ANISHCHENKO VADIM S. , ASTAKHOV SERGEY
Published: November 2008

The mixing property is characterized by the metric entropy that is introduced by Kolmogorov for dynamical systems. The Kolmogorov entropy is infinite for a stochastic system. In this work, a relative metric entropy is considered. The relative metric entropy allows to estimate the level of mixing in noisy dynamical systems. An algorithm for calculating the relative metric entropy is described and examples of the metric entropy estimation are provided for certain chaotic systems with various noise intensities. The results are compared to the entropy estimation given by the positive Lyapunov exponents.
NOISE EFFECTS IN POLYMER DYNAMICS
Authors: PIZZOLATO N. , FIASCONARO A. , SPAGNOLO B.
Published: November 2008

The study of the noise induced effects on the dynamics of a chain molecule crossing a potential barrier, in the presence of a metastable state, is presented. A two-dimensional stochastic version of the Rouse model for a flexible polymer has been adopted to mimic the molecular dynamics and to take into account the interactions between adjacent monomers. We obtain a nonmonotonic behavior of the mean first passage time and its standard deviation, of the polymer center of inertia, with the noise intensity. These findings reveal a noise induced effect on the mean crossing time. The role of the polymer length is also investigated.
MODAL MODELLING OF THE NONLINEAR RESONANT FLUID SLOSHING IN A RECTANGULAR TANK II: SECONDARY RESONANCE
Authors: HERMANN MARTIN , TIMOKHA ALEXANDER
Published: November 2008

In Part I of this work [Math. Mod. Meth. Appl. Sci.15 (2005) 1431–1458], we studied periodic (steady-state) solutions of an asymptotic nonlinear modal system which describes two-dimensional resonant sloshing in a rectangular tank. The system was derived by Faltinsen et al. (2000) under the assumption that the primary excited (lowest) natural mode gives the largest contribution to the wave patterns. We found that this assumption is not true in a certain frequency domain due to internal (secondary) resonance leading to an amplification of the second mode. This frequency domain can also be identified for the critical depth-to-breath ratio h = 0.3368 … which was discussed in Part I. In Part II, this secondary resonance is modelled by a double-dominant modal system by Faltinsen and Timokha (2001). A comparative analysis with the results from Part I is presented. The emphasis is placed on the case of the mentioned critical ratio when a double turning point arises in the branching diagram. The appearance of the double turning point explains why classical laboratory experiments by Fultz (1962) underestimate the value of the critical depth.
OBSTACLE PROBLEMS FOR DEGENERATE ELLIPTIC EQUATIONS WITH NONHOMOGENEOUS NONLINEAR BOUNDARY CONDITIONS
Authors: ANDREU FUENSANTA , IGBIDA NOUREDDINE , MAZÓN JOSÉ M. , TOLEDO JULIÁN
Published: November 2008

In this paper we study the questions of existence and uniqueness of solutions for equations of type - div a(x,Du) + γ(u) ∋ ϕ, posed in an open bounded subset Ω of ℝN, with nonlinear boundary conditions of the form a(x,Du) · η + β(u) ∋ ψ. The nonlinear elliptic operator div a(x,Du) modeled on the p-Laplacian operator Δp(u) = div (|Du|p-2Du), with p > 1, γ and β maximal monotone graphs in ℝ2 such that 0 ∈ γ(0) ∩ β(0), [Formula: see text] and the data ϕ ∈ L1(Ω) and ψ ∈ L1(∂ Ω). Since D(γ) ≠ ℝ, we are dealing with obstacle problems. For this kind of problems the existence of weak solution, in the usual sense, fails to be true for nonhomogeneous boundary conditions, so a new concept of solution has to be introduced.
QUASI-STATIC CRACK PROPAGATION BY GRIFFITH'S CRITERION
Authors: NEGRI MATTEO , ORTNER CHRISTOPH
Published: November 2008

We consider the propagation of a crack in a brittle material along a prescribed crack path and define a quasi-static evolution by means of stationary points of the free energy. We show that this evolution satisfies Griffith's criterion in a suitable form which takes into account both stable and unstable propagations, as well as an energy balance formula which accounts for dissipation in the unstable regime. If the load is monotonically increasing, this solution is explicit and almost everywhere unique. For more general loads we construct a solution via time discretization. Finally, we consider a finite element discretization of the problem and prove convergence of the discrete solutions.
A CONTINUOUS SIZE-STRUCTURED RED CORAL GROWTH MODEL
Authors: JABIN P.-E. , LEMESLE V. , AURELLE D.
Published: November 2008

The aim of this paper is to derive and analyze the mathematical properties of a new continuous size-structured model for red coral (Corallium rubrum, L.) growth. Since historical Leslie models4 are often used to deal with some ecological problems, a new approach is here proposed and give some promising results. The main advantage of using continuous model is that we hope to describe precisely the mass mortality events, observed in Mediterranean sea, and its consequences on red coral dynamics. Simulations' studies allow us to qualitatively discuss some questions about red coral populations dynamics. The development of this method should be useful for the study of the conservation of red coral populations.
ON THE SELF-DISPLACEMENT OF DEFORMABLE BODIES IN A POTENTIAL FLUID FLOW
Authors: MUNNIER ALEXANDRE
Published: November 2008

Understanding fish-like locomotion as a result of internal shape changes may result in improved underwater propulsion mechanism. In this paper, we study a coupled system of partial differential equations and ordinary differential equations which models the motion of self-propelled deformable bodies (called swimmers) in a potential fluid flow. The deformations being prescribed, we apply the least action principle of Lagrangian mechanics to determine the equations of the inferred motion. We prove that the swimmers' degrees of freedom solve a second-order system of nonlinear ordinary differential equations. Under suitable smoothness assumptions on the boundary of the fluid's domain and on the given deformations, we prove the existence and regularity of the bodies rigid motions, up to a collision between two swimmers or between a swimmer with the boundary of the fluid. Then we compute explicitly the Euler–Lagrange equations in terms of the geometric data of the bodies and of the value of the fluid's harmonic potential on the boundary of the fluid.
MARKET STATISTICS OF A PSYCHOLOGY-BASED HETEROGENEOUS AGENT MODEL
Authors: LAMBA HARBIR , SEAMAN TIM
Published: November 2008

We continue an investigation into a class of agent-based market models that are motivated by a psychologically-plausible form of bounded rationality. Some of the agents in an otherwise efficient hypothetical market are endowed with differing tolerances to the tension caused by being in the minority. This herding tendency may be due to purely psychological effects, momentum-trading strategies, or the rational response to perverse marketplace incentives.

The resulting model has the important properties of being both very simple and insensitive to its small number of fundamental parameters. While it is most certainly a caricature market, with only boundedly rational traders and the globally available information stream being modeled directly, other market participants and effects are indirectly replicated. We show that all of the most important "stylized facts" of real market statistics are reproduced by this model.

Another useful aspect of the model is that, for certain parameter values, it reduces to a standard efficient-market system. This allows us to isolate and observe the effects of particular kinds of non-rationality. To this end, we consider the effects of different asymmetries in agent behavior and show that one in particular leads to skew statistics consistent with those seen in some real financial markets.
SERIAL CORRELATION, PERIODICITY AND SCALING OF EIGENMODES IN AN EMERGING MARKET
Authors: WILCOX DIANE , GEBBIE TIM
Published: November 2008

We investigate serial correlation, periodic, aperiodic and scaling behavior of eigenmodes, i.e., daily price fluctuation time-series derived from eigenvectors, of correlation matrices of shares listed on the Johannesburg Stock Exchange (JSE) from January 1993 to December 2002.

Periodic, or calendar, components are detected by spectral analysis. We find that calendar effects are limited to eigenmodes which correspond to eigenvalues outside the Wishart range. Using a variance ratio test, we uncover serial correlation in the first eigenmodes and find slight negative serial correlation for eigenmodes within the Wishart range. Our spectral analysis and variance ratio investigations suggest that interpolating missing data or illiquid trading days with zero-order hold introduces high frequency noise and spurious serial correlation. Aperiodic and scaling behavior of the eigenmodes are investigated by using rescaled-range (R/S) methods and detrended fluctuation analysis (DFA). We find that DFA and classic and modified R/S exponents suggest the presence of long-term memory effects in the first five eigenmodes.
Irenaeus
Authors: Minns Denis
Published: November 2008

Irenaeus was a leader of the Christian community at Lyons in the last quarter of the second century. Motivated by a deep pastoral concern, he set himself to refute what he considered to be distortions of the authentic Gospel, and, in the process, he became one of the earliest Christian writers to attempt a synthesis of the major themes of theology. Largely forgotten during much of the subsequent theological tradition, he has come to be seen as a crucial figure in the early history of the development of Christian doctrine, and has much to say that modern readers will find fresh and stimulating.
A systematic review of specialised palliative care for terminal patients: which model is better?
Authors: García-Pérez L , Linertová R , Martín-Olivera R , Serrano-Aguilar P , Benítez-Rosario MA
Published: November 2008

There is evidence of improved effectiveness of specialised palliative care for terminally ill patients in comparison to conventional care. However, there is uncertainty about which model is better. The objective of this systematic review was to identify studies that compare specialised palliative care models between them assessing their effectiveness or cost-effectiveness. We searched studies published between 2003 and 2006 in several electronic databases and updated the search in MEDLINE up to 2008. Papers published before 2003 were identified by means of previous systematic reviews and manual search. Studies with broad designs comparing two or more specialised palliative care programmes in adults with terminal illness were selected. Six systematic reviews, three studies on effectiveness and one cost study were included. All systematic reviews drew the conclusion that specialised palliative care is more effective than conventional care. The methodological limitations of the original studies and the heterogeneity of programmes did not allow to draw conclusions about whether a specific model of specialised palliative care is more or less effective or cost-effective than other.
Multitemporal remote sensing of landscape dynamics and pattern change: describing natural and anthropogenic trends
Authors: Gillanders Steve N. , Coops Nicholas C. , Wulder Michael A. , Gergel Sarah E. , Nelson Trisalyn
Published: November 2008

Science and reporting information needs for monitoring dynamics in land cover over time have prompted research, and made operational, a wide variety of change detection methods utilizing multiple dates of remotely sensed data. Change detection procedures based upon spectral values are common; however, landscape pattern analysis approaches which utilize spatial information inherent within imagery present opportunities for the generation of unique and ecologically important information. While the use of two images may provide the means to identify change, the use of more than two images for long-term monitoring affords the ability to identify a greater range of processes of landscape change, including rates and dynamics. The main objective of this review is to investigate and summarize the methods and applications of land cover spatial pattern analysis using three or more image dates. The potential and the limitations of landscape pattern indices are identified and discussed to inform application recommendations. The second objective of this review is to make recommendations, including appropriate landscape pattern indices, for the application of landscape pattern analysis of a long time series of remotely sensed data to a case study involving the mountain pine beetle in British Columbia, Canada. The review concludes with recommendations for future research.
An introduction to `upside-down' remote sensing
Authors: Chapman Lee
Published: November 2008

Over the last decade, a number of applications have been developed which utilize ground-based hemispherical photography. The collection of such imagery can be described as `upside-down' remote sensing as, instead of viewing the Earth from a platform in the sky, techniques are being employed to view the sky from the Earth. This paper reviews the current theory and potential applications of `upside-down' remote sensing across the electromagnetic spectrum. To date, apparatus has been developed to detect various wavelengths between ultraviolet and infrared. Potential applications using these wavelengths are numerous and currently span urban climatology, forest climatology and transportation.
Land-cover effects on red soil rehabilitation in China: a meta-analysis
Authors: Yihe Lü  , Liding Chen  , Bojie Fu
Published: November 2008

To reverse the soil degradation problems resulting from overexploitation, ecological soil rehabilitation has already been an important pursuit in ecological and environmental research and applications. Based on journal publications and a meta-analysis approach, this paper investigates the effects, and their spatiotemporal variations, of different land covers on red soil rehabilitation in China. Results indicate that all the land covers used in red soil rehabilitation had been effective in improving degraded red soils but the degrees of effectiveness varied. Soil organic carbon was the most sensitive of the three major soil nutrients considered with regard to land-cover change during ecological rehabilitation. Coniferous and broadleaf mixed forest was detected as the most effective land cover in red soil rehabilitation. Some spatiotemporal trends of land-cover effectiveness on red soil rehabilitation exist in a statistically significant sense. These findings are important for land use and ecological rehabilitation decision-making such as the selection of a soil rehabilitation pathway and the determination of priority areas for ecological rehabilitation.
Mechanical Properties of Carbon Black-Filled High-Density Polyethylene Antistatic Composites
Authors: Liang J.Z. , Yang Q.Q.
Published: November 2008

A kind of carbon black (CB), which was surface-treated by silane-coupling agent, was compounded with high-density polyethylene (HDPE) in a twin-screw extruder, and then the composites were molded into specimens with a plastic injection molding machine. The weight fractions (φf) of the CB were 0, 3, 5 and 8%. The effects of CB loading on the mechanical properties, such as tensile yield strength, tensile fracture strength, tensile fracture elongation, flexural strength, flexural modulus and impact strength of the HDPE/CB antistatic composites, were investigated. The results expressed that the tensile fracture strength, flexural strength and flexural modulus increased obviously with an addition of φf. When φf was less than 5%, the tensile fracture elongation of the composites raised, it exhibited a maximum value when φf was approximate to 5%, then it declined. The impact strength decreased evidently with increasing φ f when φf was less than 3%, while it decreased gently when φf was more than 3%.
Biodegradation of Polyethylene—Octene Elastomer—Starch Composites in Soil
Authors: Xiaoya Shang  , Xiong Fu  , Liansheng Yang  , Xudong Chen
Published: November 2008

This study investigated the biodegradation of POE/starch and POE-g-MAH/starch composites in a natural soil environment for 6 months. Nonbiodegradable polyethylene-octene elastomer (POE) and its graft copolymer POE-g-MAH were blended with gelatinized waxy corn starch (GWCS) in different proportions. The weight loss, morphology and mechanical properties of the blend films were measured every month. Pure POE and POE-g-MAH specimens did not lose weight, while tensile strength and elongation at break only slightly changed in the soil, which indicated that pure POE and POE-g-MAH did not degrade in soil. With increasing starch content, the weight loss, tensile strength and elongation at break of POE/starch and POE-g-MAH/starch blend films reduced, as well as with increasing soil burial time, due to the biodegradation of starch. SEM photographs showed more holes and cracks with increasing starch content and burial time. The weight loss of the blends reduced evidently in the first 3 months, but much slower in the latter. Also, POE-g-MAH/starch blends showed better biodegradation than POE/starch blends.
Natural Frequencies and Mode Shapes of Composite Cylindrical Delaminated Shells by Finite Element
Authors: Acharyya Anjan Kumar , Chakravorty Dipankar , Karmakar Amit
Published: November 2008

An elaborate review of the literature of composite shells reveals that vibration characteristics of delaminated shell roofs have received very limited attention. Hence in this article dynamic behavior of delaminated composite shallow cylindrical shells with corner-point supported, simply supported and clamped boundary conditions is analyzed by finite element method using eight-noded isoparametric shell element. To ensure compatibility of deformation and equilibrium of forces and moments at the delamination crack front, a multipoint constraint algorithm is incorporated, which leads to unsymmetrical stiffness matrix. Stacking sequence, position and extent of delamination area are varied to compare the performances of delaminated cylindrical shells against those with no damage. The results are carefully observed and a set of conclusions is presented at the end of the article.
Mechanism of Translaminar Fracture in Glass/Textile Fabric Polymer Hybrid Composites
Authors: Arun K.V. , Kamat Raghavendra Dilip , Basavarajappa S.
Published: November 2008

The mechanism of translaminar failure in hybrid polymer matrix composites is a typical combination of tensile and bending loads. Experimentations have been carried out on pin loaded single edge notched tensile specimen. The results of the experimental analysis carried out on the influence of failure zone and environmental conditions on the stress intensity factor in glass/ textile fabric (GF/TF) polymer hybrid composites have been reported. The results have shown that the failure zone varies with the fabric volume, the initial crack size and the environment. The results have shown that the acidic environment has maximum influence on the failure pattern and the critical stress intensity factors.
Friction and Dry Slide Wear of Short Glass Fiber Reinforced Thermoplastic Polyurethane Composites
Authors: Suresha B.
Published: November 2008

The friction and dry slide wear behavior of short glass fiber (SGF) reinforced thermoplastic polyurethane (TPU) composites was studied in this article. The SGFs were mixed by 20, 30, and 40 wt% in TPU matrix. Composites were processed by the injection molding technique. The un-lubricated pin—on-disk wear tests were conducted by varying the load and sliding velocity. The results reveal that the slide wear loss increases with increasing load/sliding velocity. The coefficient of friction increases with increase in sliding velocity. The coefficient of friction and wear rate of the composites decreased with increase in SGF content. Further, 40% SGF reinforced TPU composite exhibited lower friction coefficient and wear rate than 20 and 30% SGF reinforced TPU composites. The worn surface features have been explained using scanning electron microscopy.
Surface Grafting of Polyethylene Fiber for Improved Adhesion to Acrylic Resin
Authors: Amornsakchai Taweechai , Pattarachindanuwong Sutawadee
Published: November 2008

Surface grafting of polyethylene (PE) fiber with methyl methacrylate (MMA) and acrylic acid (AAc) were prepared with two-stage method. Functionalization was first carried out in aqueous solution of potassium peroxydisulfate at 80°C. The fiber was then surface grafted with MMA and AAc. Single fiber composite of grafted fibers/Orthocryl® acrylic resin were prepared and adhesion evaluated with pull-out test. Acrylic matrix was prepared in two methods. In the first method, acrylic powder was bonded together with acetone. In the second, the powder was mixed with liquid monomer to form self-cure material. It was found that in the former case, in which only interdiffusion of polymer chains can occur, MMA-modified polyethylene fiber had slightly higher pull-out strength than AAc-modified fiber. In the latter case, in which chemical reaction occurred, AAc-modified fiber provided much higher pull-out strength than MMA-modified fiber. The difference in adhesion level is discussed.
Influence of maternal nicotine exposure on neonatal rat oxidant–antioxidant system and effect of ascorbic acid supplementation
Authors: Gunes T , Koklu E , Gunes I , Narin F , Koklu SS
Published: November 2008

There have been a few studies that examined the oxidative stress effects of nicotine during pregnancy and lactation. We aimed to determine the adverse effects of maternal nicotine exposure during pregnancy and lactation on oxidant–antioxidant system, and to determine a protective effect of ascorbic acid (Asc). Gravid rats were assigned into four groups. In Group 1, pregnant rats received 6-mg/kg/day nicotine subcutaneously during pregnancy from 1 to 21 days of gestation and lactation (until postnatal day 21). Group 2 received nicotine and Asc for the same period. In Group 3, the rats received nicotine during lactation. Control pregnant rats (Group 4) received only saline subcutaneously. Serum malondialdehyde (MDA), myeloperoxidase (MPO), and superoxide dismutase (SOD) levels were determined at 21 days of age. Nicotine exposure decreased birth weight and pregnancy weight gain. MDA values of the rat pups exposed to nicotine in both Groups 1 and 2 were higher than those of control and Group 3. SOD and MPO values of the groups were similar. Mean birth weight and serum MDA levels of Groups 1 and 2 were similar. Nicotine exposure via placental transfer increases oxidative stress as manifested by an increase in MDA level. Asc supplementation does not prevent the adverse effects of maternal nicotine exposure.
Effect of thioperamide on oxidative stress markers in middle cerebral artery occlusion model of focal cerebral ischemia in rats
Authors: Akhtar M , Pillai KK , Vohora D
Published: November 2008

In view of the recent evidence for the involvement of histamine in cerebral ischemia, the present study evaluated the effect of thioperamide (THP), a selective histamine H3-receptor antagonist, on middle cerebral artery occlusion (MCAO) induced focal cerebral ischemia in rats. The rats were subjected to 2 h of MCAO followed by 22 h reperfusion after which the grip strength, locomotor activity and spontaneous alternation performance were assessed. Animals were then killed and oxidative stress markers were estimated in the whole brain. An elevation of thiobarbituric acid reactive substance (TBARS) and a reduction in glutathione (GSH) and antioxidant enzymes, such as glutathione-S-transferase (GST), glutathione peroxidase (GPx), glutathione reductase (GR) and superoxide dismutase (SOD), was observed following MCAO, the last two being statistically insignificant. Pretreatment with THP (5.5 mg/kg i.p. and 11 mg/kg i.p.) significantly reversed the MCAO-induced increase in TBARS, but could not reverse the other parameters. Paradoxically, it further reduced the levels of GPx, GR and SOD. No significant changes were observed in the catalase levels and in the grip strength and spontaneous alternation behavior of rats. Locomotor activity was reduced slightly, but reversed on pretreatment with THP. The dual effect of THP on oxidative stress requires further investigation and raises doubts on its possible use in cerebral ischemia.
Toxicological evaluation of the immune function of pesticide workers, a European wide assessment
Authors: Steerenberg P , van Amelsvoort L , Colosio C , Corsini E , Fustinoni S , Vergieva T , Zaikov C , Pennanen S , Liesivuori J , Van Loveren H
Published: November 2008

In this study, the prolonged low-dose exposure of mixtures of pesticides has been examined on hematological parameters and components of the immune defense in occupationally exposed humans. This investigation was carried out in five field studies in: the Netherlands (flower bulb growers, mainly re-entry workers), Italy (vineyard workers), Finland (potato farmers), and Bulgaria (workers from a zineb factory and greenhouse workers). Immunotoxicity was studied by measuring hematological parameters, complement, immunoglobulins, lymphocyte subpopulations, natural killer cells, autoimmunity, and antibody responses to hepatitis B vaccination. The total study population consisted of 248 pesticide-exposed and 231 non-occupationally exposed workers. As a surrogate measure of pesticide exposure the urinary excretion of ethylenethiourea (ETU), the main metabolite ethylenebisdithiocarbamates was measured. A significantly higher level of ETU in occupationally exposed subjects compared with controls (2.7 ± 8.1 μg/g vs 0.5 ± 3.7 μg/g creatinine) was found. Statistically significant differences, albeit very low, were found for complement C3 and C4 and the immunoglobulin classes IgG4 and IgA. For complement and IgG4, the levels were slightly increased and the level of IgA was decreased. In the lymphocyte populations, the CD8 subpopulation was increased. No effects were found on autoimmune antibodies and antibody response to hepatitis vaccination. In conclusion, pesticide exposure under various work place conditions in Europe was associated only with some subtle effects on the immune system, which may suggest that occupational exposure to pesticides does not influence the immunologic system in a clinically significant fashion, and does not pose a significant health risk to the exposed subjects.
Chloroform deposition in renal cyst fluid of hemodialysis patients with renal cystic disorders
Authors: Ito F , Nakazawa H , Ohsaka Y , Yagisawa T , Kondo T , Hashimoto Y
Published: November 2008

Chronic exposure to chloroform (CHCl3) induces renal neoplasms in rodents and may be carcinogenic in humans, but studies on chronic CHCl3 deposition in the human body have not been performed. In this study, we examined 27 hemodialysis patients with renal cystic diseases including acquired cystic disease of the kidney (ACDK) accompanied by renal tumors at high frequency. Intracystic and serum CHCl3 concentrations were determined using a headspace gas chromatography/mass spectrometry analysis. CHCl3 was not detected in the serum in any cases, but levels ranging from <0.1 to 0.659 mg/L were found in the cyst fluid in most cases, including patients with ACDK and autosomal dominant polycystic kidney disease. Because intracystic CHCl3 deposition was not confined to ACDK cases, we were unable to evaluate the relationship between CHCl3 accumulation and carcinogenesis in ACDK. However, our results suggest that compounds such as CHCl3 accumulate in renal cyst fluid in hemodialysis patients with renal cystic diseases.
Occupational exposure to ethylenebisdithiocarbamates in agriculture and allergy: results from the EUROPIT field study
Authors: Swaen GMH , van Amelsvoort LGPM , Boers D , Corsini E , Fustinoni S , Vergieva T , Bosetti C , Pennanen S , Liesivuori J , Colosio C , van Loveren H
Published: November 2008

This epidemiological study was carried out to evaluate the possible association between occupational exposure to ethylenebisdithiocarbamates (EDBC) and allergy. The study was conducted in four countries in the European Union: The Netherlands, Finland, Italy and Bulgaria. A total of 248 workers exposed to EDBC and 231 non-occupationally exposed subjects entered the study. Exposure to EDBC was measured as urinary ethylenethiourea (ETU) in urinary samples collected at baseline and after 30 days of exposure. Several effect parameters were evaluated including questionnaire data on allergy, Phadiatop, a general allergy test, and specific IgE parameters. These data were also collected at baseline and after 30 days of exposure. Cross-sectional as well as longitudinal comparisons were made, adjusted for potential confounding factors. No association was found between exposure status, EDBC levels and allergic contact dermatitis, allergic rhinitis, food allergy or atopy as measured by the Phadiatop. The prevalence of skin irritation was elevated in the Dutch field study only and is more likely a result of plant contact rather than EDBC exposure. Occupational exposure to sunlight was noted to have a protective effect on atopy in terms of IgE positivity. We conclude that the EDBC exposure levels experienced in our field study are not associated with increased prevalence of allergic symptoms or allergy.
Pathological effects of sodium hypochlorite administration through drinking water in male Japanese quails (Coturnix japonica)
Authors: Khan A , Ullah M , Khan MZ
Published: November 2008

Fifty male Japanese quails of 40 days of age were divided into five equal groups viz. A, B, C, D, and E. Drinking water supplemented with sodium hypochlorite at dose level of 0, 25, 50, 200, and 400 mg chlorine/L, respectively was offered for 6 weeks. At the end of week 6 when no clinical signs of toxicity of sodium hypochlorite appeared, the birds in groups B and C were shifted to 100 mg chlorine/L drinking water, and this level was increased fourfold (400, 1600, 6400 mg chlorine/L drinking water) every week, till i.e., 10th week (70 day). Afterwards all the birds were killed. Depression and anorexia were prominent clinical signs observed. Reduction in feed intake, body weight, and hematological parameters appeared in a dose-dependant manner. Decreased serum total proteins and weights of liver, heart, and kidneys were recorded in birds receiving high levels of sodium hypochlorite. Intoxicated birds were emaciated. Decreased weight and volume of the testes were observed in birds receiving high levels of sodium hypochlorite. However, birds receiving 400 mg chlorine (group E) had smaller but functional testes. Birds receiving higher level of chlorine (groups B and C) had decreased weight and volume of testes, atrophied seminiferous tubules, and arrested spermatogenesis. It was concluded that sodium hypochlorite at high levels, that is, 6400 mg/L in drinking water is toxic to the quails; therefore, it should be used with caution in poultry farming as drinking water disinfectant.
Immune effects and exposure to ethylenebisdithiocarbamate pesticides in re-entry workers in the Netherlands
Authors: van Amelsvoort LGPM , Mohren DCL , Slangen JJ , Swaen G , Corsini E , Fustinoni S , Vergieva T , Bosetti C , Liesivuori J , Tarkowski M , Colosio C , van Loveren H
Published: November 2008

Ethylenebisdithiocarbamates are widely used as fungicides in agriculture. Although EBDC’s have a low acute toxicity, they are suspected to have immune effects at low doses. However, little human studies on these effects have been published. In the Netherlands, a study was conducted among pesticide exposed workers aimed at evaluating the short-term and long-term immune effects of exposure and the relation between ethylenebisdithiocarbamate and immune effects. Forty-one re-entry workers and 40 nonexposed controls were medically examined; furthermore, immune parameters were determined in blood, and all participants filled in a questionnaire regarding exposure and outcome parameters. The level of ethylenethiourea in urine was determined as indicator of exposure. No relevant adverse immune effects were found in the pesticide exposed workers compared with the nonexposed controls. Also no exposure response relationship between immune effects and ethylenebisdithiocarbamate in urine was found. This finding might be due to very low exposure levels of the re-entry work but might also be due to a lack of immunotoxicity of ethylenebisdithiocarbamate at normal exposure levels.