bluuebunny/crossref_metadata_2025 huggingface dataset:
Observed vertical structure of tropical oceanic clouds sorted in large‐scale regimes
Authors: Su Hui , Jiang Jonathan H. , Vane Deborah G. , Stephens Graeme L.
Published: December 2008

The CloudSat cloud water content (CWC) profiles are sorted by a number of large‐scale parameters obtained from reanalysis and satellite observations, including 500 hPa vertical velocity, sea surface temperature and its gradient, surface divergence, precipitation, water vapor path, convective available potential energy and lower tropospheric static stability. The sorting is physics‐based and phenomenon‐oriented. We find different degrees of clustering of cloud vertical structure in various large‐scale regimes. The dominant modes are the deep and shallow clouds with peak CWC above 7 km and below 2 km, respectively, corresponding to distinctly different large‐scale regimes. A middle‐level peak of CWC around 5–7 km is discernible associated with the large‐scale conditions similar to the shallow clouds. This study provides the first quantitative and comprehensive view of tropical CWC distributions in large‐scale regimes. These results offer insights into cloud parameterizations and serve as new observational metrics for evaluation of cloud simulations in models.
Effects of precipitation on the relationships between cloud optical thickness and drop size derived from space‐borne measurements
Authors: Kobayashi Takahisa , Masuda Kazuhiko
Published: December 2008

Cloud optical thickness and the effective radius of cloud droplets were derived by a combined use of the precipitation radar and visible and infrared scanner onboard the Tropical Rainfall Measuring Mission satellite to study the effect of precipitation on the relationship between cloud optical thickness (τ) and the effective radius (re) on a global scale. Whether τ and re correlate positively or negatively is a key to finding evidence of the indirect effects of aerosols, but up to now this has been a subject of considerable debate. No clear correlation has been reported on a global scale because τ is affected by many factors, among which the effect of precipitation is one of the most uncertain. To study the effect of precipitation, we assessed the relationship between τ and re in terms of the critical radius of cloud droplets (rc), below which precipitation hardly forms. In our analysis, there was no clear correlation between τ and re in water clouds which is consistent with many previous studies. However, interesting features of the relationship were revealed that are related to rc. Cloud optical thickness is a maximum for clouds with re around the value of rc. On a global average, cloud optical thickness tends to increase with re (positive correlation) for re < rc and to decrease (negative correlation) for re > rc. A change in the sign of the relationship was clearly observed at re ∼ rc on a global scale. These features were observed typically for non‐precipitating clouds and clouds with weak rain. The relationship is strongly affected by precipitation which should be carefully considered when using it to find evidence of the indirect effects of aerosols.
Denitrification effects on air‐sea CO2 flux in the coastal ocean: Simulations for the northwest North Atlantic
Authors: Fennel Katja , Wilkin John , Previdi Michael , Najjar Raymond
Published: December 2008

The contribution of coastal oceans to the global air‐sea CO2 flux is poorly quantified due to insufficient availability of observations and inherent variability of physical, biological and chemical processes. We present simulated air‐sea CO2 fluxes from a high‐resolution biogeochemical model for the North American east coast continental shelves, a region characterized by significant sediment denitrification. Decreased availability of fixed nitrogen due to denitrification reduces primary production and incorporation of inorganic carbon into organic matter, which leads to an increase in seawater pCO2, but also increases alkalinity, which leads to an opposing decrease in seawater pCO2. Comparison of simulations with different numerical treatments of denitrification and alkalinity allow us to separate and quantify the contributions of sediment denitrification to air‐sea CO2 flux. The effective alkalinity flux resulting from denitrification is large compared to estimates of anthropogenically driven coastal acidification.
Cluster observations of energetic electrons and electromagnetic fields within a reconnecting thin current sheet in the Earth's magnetotail
Authors: Retinò A. , Nakamura R. , Vaivads A. , Khotyaintsev Y. , Hayakawa T. , Tanaka K. , Kasahara S. , Fujimoto M. , Shinohara I. , Eastwood J. P. , André M. , Baumjohann W. , Daly P. W. , Kronberg E. A. , Cornilleau‐Wehrlin N.
Published: December 2008

We study the acceleration of energetic electrons during magnetotail reconnection by using Cluster simultaneous measurements of three‐dimensional electron distribution functions, electric and magnetic fields, and waves in a thin current sheet. We present observations of two consecutive current sheet crossings where the flux of electrons 35–127 keV peaks within an interval of tailward flows. The first crossing shows the signatures of a tailward moving flux rope. The observed magnetic field and density indicate that the flux rope was very dynamic, and a comparison with numerical simulation suggests a crossing right after coalescence of smaller flux ropes. The second crossing occurs within the ion diffusion region. The flux of electrons is largest within the flux rope where they are mainly directed perpendicular to the magnetic field. At the magnetic separatrices, the fluxes are smaller, but the energy spectra are harder and electrons are mainly field aligned. Reconnection electric fields EY ∼ 7 mV/m are observed within the diffusion region, whereas in the flux rope, EY are much smaller. Waves around lower hybrid frequency do not show a clear correlation with energetic electrons. We interpret the field‐aligned electrons at the separatrices as directly accelerated by the reconnection electric field in the diffusion region, whereas we interpret the perpendicular electrons as trapped within the flux rope and accelerated by a combination of betatron acceleration with nonadiabatic pitch‐angle scattering. Our observations indicate that thin current sheets during dynamic reconnection are important for in situ production of energetic electrons and that simultaneous measurements of electrons and electromagnetic fields within thin sheets are crucial to understand the acceleration mechanisms.
Observations of three‐dimensional Langmuir wave structure
Authors: Malaspina D. M. , Ergun R. E.
Published: December 2008

Measurements of the three‐dimensional structure of solar wind Langmuir waves made by the STEREO spacecraft are presented. Langmuir wave structure is studied using hodograms classified as one‐, two‐, or three‐dimensional. Multi‐dimensional Langmuir waves are both less‐often observed than one‐dimensional events and clustered in time. These observations show that a minority of Langmuir waves have electric fields transverse to the local magnetic field direction. We present a new explanation for this transverse structure based on an interpretation of Langmuir waves as eigenmodes of solar wind density cavities. These new observations are compared with previous theories for transverse wave structure and the eigenmode interpretation is found to be consistent with STEREO observations.
Prediction of thrusting sequences in accretionary wedges
Authors: Cubas N. , Leroy Y. M. , Maillot B.
Published: December 2008

The main objective is to determine the three stages of the life of a thrust in an accretionary wedge which are the onset of thrusting along its ramp, the development with the construction of the relief, and the arrest because of the onset of another thrusting event. A simple kinematics is proposed for the geometry of the developing thrust fold based on rigid regions separated by velocity discontinuities along which work is dissipated according to the Coulomb criterion. The evolution of the thrust fold satisfies mechanical equilibrium and is optimized at every time of the three stages to provide the least upper bound in tectonic force according to the maximum strength theorem. The development of the thrust or its arrest because of the initiation of another thrust is decided by selecting the event which leads to the least upper bound in tectonic force. The approach is first validated by proving that the critical slope angle αc for the classical triangular wedge is properly captured. It is shown that a perturbation, in the form of an extra relief in this perfectly triangular geometry, leads to the onset of thrusting with the ramp or the back thrust outcropping either at the back or to the front of the perturbation, respectively, for a range of slope dip close to the critical angle αc. The study of normal thrust sequences (from the rear to the front in the wedge toe) reveals that weakening of the ramp, accounted for by changing its friction angle from an initial to a smaller final value, is necessary for each thrust to have a finite life span. This life span is longer with a larger relief buildup for more pronounced weakening. Decreasing the décollement friction angle results in an increase in the number of thrusts in the sequence, each thrust creating milder relief. The normal sequence is ended with the first out of sequence thrust which occurs earlier for smaller weakening over the ramp. The proposed methodology is partly used to construct an inverse method proposed to assess the likeliness for the transfer of activity from the active to the incipient thrust in a section of Nankai's accretionary wedge. The inverse method provides the initial friction angle over the incipient ramp and the final friction angle over the fully active ramp, from the geometry of the corresponding thrusts, and the topography. It is shown that the friction angle over the incipient ramp is most likely to be larger then the one over the active ramp, justifying a key hypothesis needed to predict discrete sequences of thrusting.
Seasonal and interannual variations of upper ocean heat balance off the west coast of Australia
Authors: Feng Ming , Biastoch Arne , Böning Claus , Caputi Nick , Meyers Gary
Published: December 2008

The Leeuwin Current, a warm, poleward flowing eastern boundary current, dominates the surface circulation off the west coast of Australia and has profound influence on regional marine ecosystem and fisheries recruitment. In this study, the seasonal and interannual variations of upper ocean heat balance in the Leeuwin Current region are analyzed by using an eddy‐resolving numerical model simulation, as a first step to quantify the climate impacts on regional ocean thermodynamics and marine ecosystem. The volume transport and heat advection of the Leeuwin Current are stronger during the austral winter on the seasonal cycle and are stronger during a La Nina event on the interannual scale. On both seasonal and interannual timescales, the mixed layer heat budget off the west coast of Australia is predominantly balanced between the variations of the Leeuwin Current heat advection and heat flux across the air‐sea interface. On the interannual timescale, the variation of the Leeuwin Current heat advection tends to lead that of the air‐sea (latent) heat flux by two months, which is likely a reflection of advection timescales of the Leeuwin Current and its eddy field. The interannual variation of the average February–April sea surface temperature off the west coast of Australia, which is crucial for the larval settlement of western rock lobster, is mostly influenced by the Leeuwin Current heat advection as well as the ocean memory from the previous austral winter, with the air‐sea heat exchange playing a buffering role.
Aerosol vertical distribution in dust outflow over the Atlantic: Comparisons between GEOS‐Chem and Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO)
Authors: Generoso Sylvia , Bey Isabelle , Labonne Mathieu , Bréon François‐Marie
Published: December 2008

Vertically resolved attenuated backscatter from the Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) mission and aerosol optical thickness (AOT) from the Moderate‐resolution Imaging Spectroradiometer (MODIS) are used to characterize the Saharan dust outflow over the Atlantic and to evaluate results from a global chemical and transport model (GEOS‐Chem). We first document two events of dust plume transport from the Sahara to the American coast representative of summer and winter conditions. Observed and model‐derived attenuated backscatter profiles agree qualitatively well, suggesting that the altitudes of the aerosol layers over the Atlantic are well reproduced by the model. In both the model and the observations, dust plumes extend up to 8 km in summer and up to 4 km in winter over the Atlantic close to the source regions and gradually descend throughout their travel over the Atlantic. We find however that, in summertime, observed AOT are overestimated by the model close to the source regions and underestimated in the remote regions, suggesting a too weak transport toward the western Atlantic and/or a too strong deposition over the Caribbean Sea. We then use our simulation to characterize the deposition flux of dust in this region. Half of the dust deposited on the surface of the open ocean in 2006 in this area occurs during summer, 20% during each of winter and spring, and 10% in the fall. During a 1‐week dust episode in July 2006 that we investigated, 5 Tg of dust were deposited (4% of the annual total in the region).
Composition of the Venus mesosphere measured by Solar Occultation at Infrared on board Venus Express
Authors: Vandaele A. C. , De Mazière M. , Drummond R. , Mahieux A. , Neefs E. , Wilquet V. , Korablev O. , Fedorova A. , Belyaev D. , Montmessin F. , Bertaux J.‐L.
Published: December 2008

Solar Occultation at Infrared (SOIR), which is a part of the Spectroscopy for Investigation of Characteristics of the Atmosphere of Venus (SPICAV) instrument on board Venus Express, combines an echelle‐grating spectrometer with an acoustooptical tunable filter. It performs solar occultation measurements in the IR region at a high spectral resolution better than all previously flown planetary spectrometers. The wavelength range probed allows for a detailed chemical inventory of the Venus atmosphere above the cloud layer, with an emphasis on the vertical distribution of the gases. A general description of the retrieval technique is given and is illustrated by some results obtained for CO2 and for a series of minor constituents, such as H2O, HDO, CO, HCl, and HF. Detection limits for previously undetected species will also be discussed.
Partial least squares methods for spectrally estimating lunar soil FeO abundance: A stratified approach to revealing nonlinear effect and qualitative interpretation
Authors: Li Lin
Published: December 2008

Partial least squares (PLS) regressions were applied to lunar highland and mare soil data characterized by the Lunar Soil Characterization Consortium (LSCC) for spectral estimation of the abundance of lunar soil chemical constituents FeO and Al2O3. The LSCC data set was split into a number of subsets including the total highland, Apollo 16, Apollo 14, and total mare soils, and then PLS was applied to each to investigate the effect of nonlinearity on the performance of the PLS method. The weight‐loading vectors resulting from PLS were analyzed to identify mineral species responsible for spectral estimation of the soil chemicals. The results from PLS modeling indicate that the PLS performance depends on the correlation of constituents of interest to their major mineral carriers, and the Apollo 16 soils are responsible for the large errors of FeO and Al2O3 estimates when the soils were modeled along with other types of soils. These large errors are primarily attributed to the degraded correlation FeO to pyroxene for the relatively mature Apollo 16 soils as a result of space weathering and secondary to the interference of olivine. PLS consistently yields very accurate fits to the two soil chemicals when applied to mare soils. Although Al2O3 has no spectrally diagnostic characteristics, this chemical can be predicted for all subset data by PLS modeling at high accuracies because of its correlation to FeO. This correlation is reflected in the symmetry of the PLS weight‐loading vectors for FeO and Al2O3, which prove to be very useful for qualitative interpretation of the PLS results. However, this qualitative interpretation of PLS modeling cannot be achieved using principal component regression loading vectors.
Linking soil organic matter dynamics and erosion‐induced terrestrial carbon sequestration at different landform positions
Authors: Berhe Asmeret Asefaw , Harden Jennifer W. , Torn Margaret S. , Harte John
Published: December 2008

Recently, the potential for terrestrial carbon (C) sequestration by soil erosion and deposition has received increased interest. Erosion and deposition constitute a sink for atmospheric carbon dioxide relative to a preerosional state or a noneroding scenario, if the posterosion watershed C balance is increased due to (1) partial replacement of eroded C by new photosynthate in the eroded site; and (2) preservation from decomposition of at least some eroded soil organic carbon (SOC) arriving in depositional settings. Little is known, however, about differences in C dynamics at different erosional and depositional landform positions within the same eroding system. We determined the contribution of different landform positions to erosion‐induced terrestrial C sequestration by measuring rates of net primary productivity (NPP), replacement of eroded C, and decomposition of organic matter (OM) at four categorically different landform positions within a naturally eroding toposequence in northern California. We found that eroded C is replaced by NPP 15 times over in the summit of the site studied and 5 times over in the slope. Profile‐averaged, long‐term rate constant for SOM decomposition was 2 to 14 times slower in the depositional settings compared with that in eroding slopes. As a result, the inventory of C in the depositional settings was 2 to 3 times larger than that of the eroding positions. Owing to both C replacement at eroding sites and reduced rates of OM decomposition in depositional sites, soil erosion constitutes a C sink from the atmosphere at our study site.
Influences of the macrophyte (Scirpus mariqueter) on phosphorous geochemical properties in the intertidal marsh of the Yangtze Estuary
Authors: Hou L. J. , Liu M. , Ou D. N. , Yang Y. , Xu S. Y.
Published: December 2008

The role of the marsh plant (Scirpus mariqueter) in phosphorus (P) biogeochemical cycling was investigated in the present study. The marsh plant had a significant influence on P adsorption, benthic fluxes and P speciation in the intertidal system. The adsorption capacities of P were significantly higher in the rhizosphere sediments (54.38–77.12 mg kg−1) than in the bare sediments (43.91–54.81 mg kg−1). Lower half saturation concentration constants also appeared in the rhizosphere sediments. Similar adsorption kinetic patterns were found for the bare and vegetated habitats, which showed an initial fast P adsorption reaction, followed by a slow adsorption process. However, compared with the unvegetated sediments, the relatively higher adsorption rate appeared in the rhizosphere sediments during the fast adsorption stage. Also, soluble inorganic P was effluxed into the overlying water in the unvegetated habitat. In contrast, soluble inorganic P was transported from the overlying water into the vegetated sediments during the growth season of S. mariqueter. The comparative analysis of P speciation in both bare and vegetated habitats revealed that S. mariqueter could enhance the accumulation of Fe‐bound P, authigenic P and organic P in the rhizosphere sediments. The important role of S. mariqueter in P removal and storage has significant implications for the conservation and management of the Yangtze estuarine and intertidal marsh.
Improving the simulation of extreme precipitation events by stochastic weather generators
Authors: Furrer Eva M. , Katz Richard W.
Published: December 2008

Stochastic weather generators are commonly used to generate scenarios of climate variability or change on a daily timescale. So the realistic modeling of extreme events is essential. Presently, parametric weather generators do not produce a heavy enough upper tail for the distribution of daily precipitation amount, whereas those based on resampling have inherent limitations in representing extremes. Regarding this issue, we first describe advanced statistical tools from ultimate and penultimate extreme value theory to analyze and model extremal behavior of precipitation intensity (i.e., nonzero amount), which, although interesting in their own right, are mainly used to motivate approaches to improve the treatment of extremes within a weather generator framework. To this end we propose and discuss several possible approaches, none of which resolves the problem at hand completely, but at least one of them (i.e., a hybrid technique with a gamma distribution for low to moderate intensities and a generalized Pareto distribution for high intensities) can lead to a substantial improvement. An alternative approach, based on fitting the stretched exponential (or Weibull) distribution to either all or only high intensities, is found difficult to implement in practice.
Haemophilia care in adolescents – compliance and lifestyle issues
Authors: PETRINI P. , SEUSER A.
Published: December 2008

Summary.  Adolescence is characterized by simultaneous physical, psychological, social and sexual changes that compound the challenges faced by parents, health care providers and adolescent haemophilia patients themselves. Compliance with prophylactic factor replacement therapy frequently declines when patients pass from childhood to adolescence. Familiarity with long‐term joint damage is lacking among the current generation of children who have grown up with prophylactic treatment and the tendency of teenagers to focus primarily on short‐term goals increases the likelihood that regular prophylactic replacement therapy receives low priority. Most adolescents continue prophylactic treatment prior to physical or social activities because short‐term goals are more likely to be perceived as relevant. The most important factor that influences compliance is support from parents, peers and caregivers, who provide encouragement and support active participation in health care management. During adolescence, personalized treatment strategies that suit the patient and his lifestyle are essential to ensure optimal outcomes. Physical activity is important for all adolescents and can contribute to better coordination, endurance, flexibility and strength. Physical training also contributes to healthier joints and reduces the risk of bleeding episodes in teenagers with haemophilia; however, the selection of an appropriate sport that minimizes the risk of injury and matches the patient’s skill and needs is important. Children with haemophilia may have disease‐related functional deficits and often exhibit subclinical findings in the joints; therefore an orthopaedic examination, fitness check and motion analysis may assist in guiding preventive physiotherapy and the choice of sport.
Challenges and controversies in haemophilia care in adulthood
Authors: DOLAN G. , HERMANS C. , KLAMROTH R. , MADHOK R. , SCHUTGENS R. E. G. , SPENGLER U.
Published: December 2008

Summary.  Overall life expectancy and quality of life among persons with haemophilia have increased in recent years, primarily because of the advances in factor replacement therapy and better treatment of infectious diseases. Older haemophilic patients now face aging co‐morbidities that are common in the general male population, such as cardiovascular or metabolic diseases, prostate hypertrophy and hepatic, prostate and other cancers. The prevalence of cardiovascular disease and incidence of vascular events among older haemophilic patients can be expected to increase and haemophilic patients may become prone to some cardiovascular risk factors, warranting preventative measures. The treatment of long‐term complications of hepatitis C virus infection such as liver cirrhosis and hepatic cancer can be expected to be required in a large portion of the older haemophilia population for some years to come. Appropriate antiviral treatment and close monitoring for possible disease advancement will constitute an important part of routine medical care, and special considerations may be appropriate in conjunction with invasive procedures, chemo‐ or radiotherapy. At the moment, hard data on which to base the management of these conditions are largely lacking, but can be expected to increase dramatically in the coming decades. In the meantime, the ageing population of haemophilia patients should be offered the same comprehensive health care offered to the general population, which may require a restructuring of health care delivery.
OFFSHORING, OUTSOURCING AND PRODUCTION RELOCATIONS — LABOR MARKET EFFECTS IN THE OECD AND DEVELOPING ASIA
Authors: KIRKEGAARD JACOB F.
Published: December 2008

This paper evaluates data validity of available empirical sources and the extent of services sector labor market impact of offshoring in the US, EU-15 and Japan. A three-tier data validity hierarchy is identified, while the employment impact of offshoring in the three regions is found to be limited. Correspondingly, developing Asia is unlikely to experience large-scale employment gains as a destination region. Instead, the crucial role of domestic entrepreneurs in the growth of the Indian IT-related services industry is highlighted, as are the twin educational challenges facing developing Asia: the need to improve both primary and higher education simultaneously.
INDIA AND SERVICES OUTSOURCING IN ASIA
Authors: CHANDA RUPA
Published: December 2008

This paper examines India's role in services outsourcing within Asia. It provides a brief overview of the global as well as Indian services outsourcing industry. The core section examines India's relationship with other Asian countries such as China, the Philippines, Vietnam, and Malaysia in service outsourcing. It examines the extent to which these countries pose a competitive challenge to India and concludes that at this time, India is far ahead although it is likely to face growing competition as its costs rise. The paper highlights the need to move beyond this comparative paradigm and to examine the complementary and collaborative opportunities that exist between India and other Asian countries in services outsourcing. It concludes that there is considerable scope for such synergies and that India and other Asian countries can form different parts of a larger regional or global delivery model. Regional and bilateral agreements within Asia can also facilitate this process.
BIANCHI TYPE V COSMOLOGICAL MODELS WITH PERFECT FLUID AND HEAT CONDUCTION IN LYRA'S GEOMETRY
Authors: RAM SHRI , ZEYAUDDIN MOHD. , SINGH C. P.
Published: December 2008

The field equations within the framework of Lyra's geometry with a time-dependent displacement vector field for a Bianchi type-V space–time filled with a perfect fluid and heat flow are presented. Two different classes of physically viable solutions are obtained by using a special law of variation for the generalized mean Hubble's parameter which correspond to singular and nonsingular models with constant deceleration parameter. These models are found to be consistent with the observations on the present day universe. Some thermodynamical relations are studied. The physical and kinematical behaviors of the models are also discussed.
GENERATING SHAPE INVARIANT POTENTIALS
Authors: GANGOPADHYAYA ASIM , MALLOW JEFFRY V.
Published: December 2008

We transform the shape invariance condition, a difference-differential equation of supersymmetric quantum mechanics, into a local partial differential equation. We develop a new method for generating translationally shape invariant potentials from this equation. We generate precisely all the known shape invariant potentials, and argue that there are unlikely to be others.
BIANCHI I WITH VARIABLE G AND Λ: SELF-SIMILAR APPROACH
Authors: BELINCHÓN JOSÉ ANTONIO
Published: December 2008

In this paper we show how to study under the self-similarity hypothesis a perfect fluid Bianchi I model with variables G and Λ, but under the condition div T≠0. We arrive to the conclusion that: G and Λ are decreasing time functions (the sign of Λ depends on the equation of state), while the exponents of the scale factor must satisfy the conditions [Formula: see text] and [Formula: see text], ∀ω ∈ (-1, 1), relaxing in this way the Kasner conditions. We also show the connection between the behavior of G and the Weyl tensor.
THEORETICAL STUDIES OF ANHARMONIC EFFECT IN THE RICE–RAMSPERGER–KASSEL–MARCUS THEORY
Authors: YAO L. , LIU Y. L. , LIN S. H.
Published: December 2008

The purpose of this paper is to propose a theoretical approach, which can evaluate anharmonic effects on the rate constants within the transition state theory. In treating unimolecular reactions under collision-free conditions by using the RRKM theory, we make use of the inverse Laplace transformation of the partition functions to obtain both the total number of states for the activated complex and density of states for the reactant with the Morse oscillator potential. To demonstrate the applications of our theoretical approach, we choose some model systems and a real reaction as examples.
THE RELEVANCE-STRENGTH IN A SCALE-FREE NETWORK
Authors: KIM HYUN-JOO
Published: December 2008

We introduce a new quantity, relevance-strength which describes the relevance of a node to the others in a scale-free network. We define a weight between two nodes i and j based on the shortest path length between them and the relevance-strength of a node is defined as the sum of the weights between it and others. For the Barabási and Albert model which is a well-known scale-free network model, we measure the relevance-strength of each node and study the correlations with other quantities, such as the degree, the mean degree of neighbors of a node, and the mean relevance-strength of neighbors. We find that the relevance-strength shows power law behaviors and the crossover behaviors for the degree and the mean relevance-strength of neighbors. Also, we study the scaling behaviors of the relevance-strength for various average relevance-strength for all nodes.
PAIRWISE ENTANGLEMENT IN THE TETRAHEDRAL LATTICE WITH HEISENBERG INTERACTIONS
Authors: HU MING-LIANG
Published: December 2008

By using the concept of negativity, we determine entanglement features of the tetrahedral lattice with Heisenberg interactions. It is found that except [Formula: see text] for the case of (1/2-1/2-1-1) mixed spins, there is no pairwise entanglement between any two spins at any temperature when B = 0. When B increases after B = 0, the ground-state negativities exhibit square wave or stepwise structures, and experience sharply descents to lower values at some energy-level crossing points. For thermal entanglement, the negativities exhibit ridge-like or staircase structures as B increases, and there are regions in the B–T plane where an increase of temperature may help to enhance the entanglement.
FOLDING FREE ENERGY LANDSCAPE OF THE DECAPEPTIDE CHIGNOLIN
Authors: DOU XIANGHUA , WANG JIHUA
Published: December 2008

Chignolin is an artificially designed ten-residue (GYDPETGTWG) folded peptide, which is the smallest protein and provides a good template for protein folding. In this work, we completed four explicit water molecular dynamics simulations of Chignolin folding using GROMOS and OPLS-AA force fields from extended initial states without any experiment informations. The four-folding free energy landscapes of the peptide has been drawn. The folded state of Chignolin has been successfully predicated based on the free energy landscapes. The four independent simulations gave similar results. (i) The four free energy landscapes have common characters. They are fairly smooth, barrierless, funnel-like and downhill without intermediate state, which consists with the experiment. (ii) The different extended initial structures converge at similar folded structures with the lowest free energy under GROMOS and OPLS-AA force fields. In the GROMOS force field, the backbone RMSD of the folded structures from the NMR native structure of Chignolin is only 0.114 nm, which is a stable structure in this force field. In the OPLS-AA force field, the similar results have been obtained. In addition, the smallest RMSD structure is in better agreement with the NMR native structure but unlikely stable in the force field.
EXISTENCE RESULTS FOR NONDENSELY DEFINED IMPULSIVE SEMILINEAR FUNCTIONAL DIFFERENTIAL EQUATIONS WITH STATE-DEPENDENT DELAY
Authors: Abada Nadjet , Agarwal Ravi P. , Benchohra Mouffak , Hammouche Hadda
Published: December 2008

In this paper, we shall establish sufficient conditions for the existence of integral solutions for some nondensely defined impulsive semilinear functional differential equations with state-dependent delay in separable Banach spaces. We shall rely on a fixed point theorem for the sum of completely continuous and contraction operators.
SEMIGROUPS OF TREE LANGUAGES
Authors: Denecke K. , Sarasit N.
Published: December 2008

Sets of terms of type τ are called tree languages (see [6]). There are several possibilities to define superposition operations on sets of tree languages. On the basis of such superposition operations we define binary associative operations on tree languages and investigate the properties of the arising semigroups. We characterize idempotent and regular elements and Green's relations [Formula: see text] and [Formula: see text]. Moreover, we determine constant, left-zero and right-zero subsemigroups and rectangular bands.
REPRESENTATIONS OF ARITHMETIC SUMS OVER NON-TRIVIAL ZEROS OF THE ZETA FUNCTION
Authors: Deza Elena , Varukhina Lidiya
Published: December 2008

We obtain representations over non-trivial zeros of zeta function for two arithmetic functions ψ1(x) = ∑n≤x (x - n)Λ(n) and [Formula: see text]. This result is similar to classical representations of such kind for the Chebyshev functionψ(x) = ∑n≤x Λ(n).
REFINEMENTS OF THE CONTINUOUS TRIANGLE INEQUALITY FOR THE BOCHNER INTEGRAL IN HILBERT SPACES
Authors: Dragomir S. S.
Published: December 2008

Some refinements of the continuous triangle inequality for the Bochner integral of vector-valued functions in Hilbert spaces are given. Applications for norm and numerical radius operator inequalities are provided. A particular case of interest for complex-valued functions is pointed out as well.
NILPOTENT FINITE RINGS WITH PLANAR ZERO-DIVISOR GRAPHS
Authors: KUZ'MINA A. S. , MALTSEV Yu. N.
Published: December 2008

The zero-divisor graph Γ(R) of an associative ring R is the graph with all vertices non-zero zero-divisors (one-sided and two-sided) of R, and two distinct vertices x and y are joined by an edge iff xy = 0 or yx = 0 ([10]). In the present paper, we describe all nilpotent finite rings with planar zero-divisor graphs.
CONSTRUCTING NEW MATRICES AND INVESTIGATING THEIR DETERMINANTS
Authors: Mirashe N. , Moghaddamfar A. R. , Mozafari S. H. , Pooya S. M. H. , Navid Salehy S. , Nima Salehy S.
Published: December 2008

Let λ = (λi)i ≥ 1, μ = (μi)i ≥ 1, ν = (νi)i ≥ 1, ω = (ωi)i ≥ 1 and ψ = (ψi)i ≥ 1 be given sequences, and let (ai,j)i,j ≥ 1 be the doubly indexed sequence given by the recurrence [Formula: see text](i ≥ 3, j ≥ 2), with various choices for the two first rows a1,j, a2,j and first column ai,1. Note that the coefficients depend on the row index only. In this article we study the principal minors of doubly indexed sequences (ai,j)i,j ≥ 1 for certain sequences and certain initial conditions. Moreover, let (bi,j)i,j ≥ 1 be the doubly indexed sequence given by the recurrence [Formula: see text] with various choices for the first row b1,j and first column bi,1. We also study the principal minors of doubly indexed sequence (bi,j)i,j ≥ 1.
On $\mathfrak{F}_n$-SUPPLEMENTED SUBGROUPS OF FINITE GROUPS
Authors: Yang Nanying , Guo Wenbin
Published: December 2008

Let G be a finite group and denote a formation of finite groups by [Formula: see text]. We call a subgroup H of G[Formula: see text]-supplemented in G if there exists a normal subgroup K of G such that G = HK and (H ∩ K)HG/HG is contained in the [Formula: see text]-hypercenter [Formula: see text] of G/HG. In this paper, we use [Formula: see text]-supplemented subgroups to study the structure of finite groups. Some known results in the literature are generalized.
GENERALIZATION OF THE FRAME OPERATOR AND THE CANONICAL DUAL FRAME TO BANACH SPACES
Authors: Stoeva Diana T.
Published: December 2008

Xd-frames for Banach spaces are generalization of Hilbert frames. In this paper we extend the concepts of frame operator and canonical dual to the case of Xd-frames. For a given Xd-frame {gi} for the Banach space X we define an Xd-frame map𝕊 : X → X* and determine conditions, which imply that 𝕊 is invertible and the family {𝕊-1gi} is an [Formula: see text]-frame for X* such that f = ∑gi(f)𝕊-1gifor every f ∈ X and g = ∑g(𝕊-1gi)gifor every g ∈ X*. If X is a Hilbert space and {gi} is a frame for X, then the ℓ2-frame map 𝕊 gives the frame operator S and the family {𝕊-1gi} coincides with the canonical dual of {gi}.
Lung mechanical and vascular changes during positive- and negative-pressure lung inflations: importance of reference pressures in the pulmonary vasculature
Authors: Peták Ferenc , Albu Gergely , Lele Enikö , Hantos Zoltán , Morel Denis R. , Fontao Fabienne , Habre Walid
Published: December 2008

The continuous changes in lung mechanics were related to those in pulmonary vascular resistance (Rv) during lung inflations to clarify the mechanical changes in the bronchoalveolar system and the pulmonary vasculature. Rv and low-frequency lung impedance data (Zl) were measured continuously in isolated, perfused rat lungs during 2-min inflation-deflation maneuvers between transpulmonary pressures of 2.5 and 22 cmH2O, both by applying positive pressure at the trachea and by generating negative pressure around the lungs in a closed box. Zl was averaged and evaluated for 2-s time windows; airway resistance (Raw), parenchymal damping and elastance (H) were determined in each window. Lung inflation with positive and negative pressures led to very similar changes in lung mechanics, with maximum decreases in Raw [−68 ± 4 (SE) vs. −64 ± 18%] and maximum increases in H (379 ± 36 vs. 348 ± 37%). Rv, however, increased with positive inflation pressure (15 ± 1%), whereas it exhibited mild decreases during negative-pressure expansions (−3 ± 0.3%). These results demonstrate that pulmonary mechanical changes are not affected by the opposing modes of lung inflations and confirm the importance of relating the pulmonary vascular pressures in interpreting changes in Rv.
Influence of acute exercise with and without carbohydrate replacement on postprandial lipid metabolism
Authors: Harrison Michael , O'Gorman Donal J. , McCaffrey Noel , Hamilton Marc T. , Zderic Theodore W. , Carson Brian P. , Moyna Niall M.
Published: December 2008

Acute exercise, undertaken on the day before an oral fat tolerance test (OFTT), typically reduces postprandial triglycerides (TG) and increases high-density lipoprotein-cholesterol (HDL-C). However, the benefits of acute exercise may be overstated when studies do not account for compensatory changes in dietary intake. The objective of this study was to determine the influence of acute exercise, with and without carbohydrate (CHO) replacement, on postprandial lipid metabolism. Eight recreationally active young men underwent an OFTT on the morning after three experimental conditions: no exercise [control (Con)], prolonged exercise without CHO replacement (Ex-Def) and prolonged exercise with CHO replacement to restore CHO and energy balance (Ex-Bal). The exercise session in Ex-Def and Ex-Bal consisted of 90 min cycle ergometry at 70% peak oxygen uptake (V̇o2peak) followed by 10 maximal 1-min sprints. CHO replacement was achieved using glucose solutions consumed at 0, 2, and 4 h postexercise. Muscle glycogen was 40 ± 4% ( P < 0.05) and 94 ± 3% ( P = 0.24) of Con values on the morning of the Ex-Def and Ex-Bal OFTT, respectively. Postprandial TG were 40 ± 14% lower and postprandial HDL-C, free fatty acids, and 3-hydroxybutyrate were higher in Ex-Def compared with Con ( P < 0.05). Most importantly, these exercise effects were not evident in Ex-Bal. Postprandial insulin and glucose and the homeostatic model assessment of insulin resistance (HOMAIR) were not significantly different across trials. There was no relation between the changes in postprandial TG and muscle glycogen across trials. In conclusion, the influence of acute exhaustive exercise on postprandial lipid metabolism is largely dependent on the associated CHO and energy deficit.
Aberrant allele-specific replication, independent of parental origin, in blood cells of cancer patients
Authors: Dotan Zohar A , Dotan Aviva , Ramon Jacob , Avivi Lydia
Published: December 2008

Background

Allelic counterparts of biallelically expressed genes display an epigenetic symmetry normally manifested by synchronous replication, different from genes subjected to monoallelic expression, which normally are characterized by an asynchronous mode of replication (well exemplified by the SNRPN imprinted locus). Malignancy was documented to be associated with gross modifications in the inherent replication-timing coordination between allelic counterparts of imprinted genes as well as of biallelically expressed loci. The cancer-related allelic replication timing aberrations are non-disease specific and appear in peripheral blood cells of cancer patients, including those with solid tumors. As such they offer potential blood markers for non-invasive cancer test. The present study was aimed to gain some insight into the mechanism leading to the replication timing alterations of genes in blood lymphocytes of cancer patients.

Methods

Peripheral blood samples derived from patients with prostate cancer were chosen to represent the cancerous status, and samples taken from patients with no cancer but with benign prostate hyperplasia were used to portray the normal status. Fluorescence In Situ Hybridization (FISH) replication assay, applied to phytohemagglutinin (PHA)-stimulated blood lymphocytes, was used to evaluate the temporal order (either synchronous or asynchronous) of genes in the patients' cells.

Results

We demonstrated that: (i) the aberrant epigenetic profile, as delineated by the cancer status, is a reversible modification, evidenced by our ability to restore the normal patterns of replication in three unrelated loci (CEN15, SNRPN and RB1) by introducing an archetypical demethylating agent, 5-azacytidine; (ii) following the rehabilitating effect of demethylation, an imprinted gene (SNRPN) retains its original parental imprint; and (iii) the choice of an allele between early or late replication in the aberrant asynchronous replication, delineated by the cancer status, is not random but is independent of the parental origin.

Conclusion

The non-disease specific aberrant epigenetic profile displayed in peripheral blood cells of patients with a solid tumour (unlike genetic aberrations) can be reversed, by an epigenetic drug applied in vitro, to the normal. It appears that the cancerous status differentiates between two allelic counterparts in a non-random manner, but independent of the parental origin
Ultrastructure and physical properties of an adhesive surface, the toe pad epithelium of the tree frog, Litoria caerulea White
Authors: Scholz Ingo , Barnes W. Jon P. , Smith Joanna M. , Baumgartner Werner
Published: December 2008

Knowledge of both surface structure and physical properties such as stiffness and elasticity are essential to understanding any adhesive system. In this study of an adhesion surface in the tree frog, Litoria caerulea White, a variety of techniques including atomic force microscopy were used to investigate the microstructure and properties of an epithelium that adheres through wet adhesion. Litoria toe pads consist of a hexagonal array of flat-topped epithelial cells, separated by mucus-filled channels. Under an atomic force microscope, this `flat' surface is highly structured at the nanoscale, consisting of a tightly packed array of columnar nanopillars (described as hemidesmosomes by previous authors), 326±84 nm in diameter, each of which possesses a central dimple 8±4 nm in depth. In fixed tissue (transmission electron microscopy), the nanopillars are approximately as tall as they are broad. At the gross anatomical level, larger toe pads may be subdivided into medial and lateral parts by two large grooves. Although the whole toe pad is soft and easily deformable, the epithelium itself has an effective elastic modulus equivalent to silicon rubber (mean Eeff=14.4±20.9 MPa; median Eeff=5.7 MPa), as measured by the atomic force microscope in nanoindentation mode. The functions of these structures are discussed in terms of maximising adhesive and frictional forces by conforming closely to surface irregularities at different length scales and maintaining an extremely thin fluid layer between pad and substrate. The biomimetic implications of these findings are reviewed.
Freeze tolerance in an arctic Alaska stonefly
Authors: Walters Kent R. , Sformo Todd , Barnes Brian M. , Duman John G.
Published: December 2008

Most aquatic insects do not survive subzero temperatures and, for those that do, the physiology has not been well characterized. Nemoura arctica is a species of stonefly widely distributed throughout arctic and subarctic Alaska. We collected nymphs from the headwaters of the Chandalar River, where we recorded streambed temperatures as low as –12.7°C in midwinter. When in contact with ice, autumn-collected N. arctica cool to –1.5±0.4°C before freezing, but individuals survived temperatures as low as –15°C, making this the first described species of freeze-tolerant stonefly. N. arctica clearly survive freezing in nature, as winter-collected nymphs encased in ice demonstrated high survivorship when thawed. In the laboratory, 87% of N. arcticanymphs frozen to –15°C for 2.5 weeks survived and, within one month of thawing, 95% of the last-instar nymphs emerged. N. arctica produce both glycerol and ice-binding factors (e.g. antifreeze protein) in response to low temperature. Hemolymph glycerol concentrations increased from 3 mmol l–1 to 930±114 mmol l–1 when temperatures were decreased from 4°C to –8°C, and N. arctica continued to produce glycerol even while frozen. Although the hemolymph of individual cold-acclimated nymphs occasionally exhibited more than a degree of thermal hysteresis, typically the hemolymph exhibited only hexagonal crystal growth, indicating a low concentration of ice-binding factor. Hemolymph of nymphs acclimated to subzero temperatures had recrystallization inhibition. These results demonstrate that, in the face of freezing conditions, N. arctica exhibit overwintering adaptations similar to those of terrestrial insects.