bluuebunny/crossref_metadata_2025 huggingface dataset:
Phytochemical study of Solanum lycocarpum (St. Hil) unripe fruit and its effects on rat gestation
Authors: Schwarz Aline , Pinto Ernani , Haraguchi Mitsue , Oliveira Cláudio Alvarenga de , Bernardi Maria Martha , Spinosa Helenice de Souza
Published: July 2007

Solanum lycocarpum, St. Hil (Solanaceae) is a common native shrub in the Brazilian cerrado. The fruits are used in folk medicine as a hypoglycaemic agent in the management of diabetes, obesity and to decrease cholesterol levels. In this study the glycoalkaloids, solamargine and solasonine, were isolated from unripe fruits of S. lycocarpum. To evaluate the effects of the fruits on gestation, pregnant rats (n = 25) were fed from day 6 to 22 with chow containing 10% of dried and ground unripe fruits. The control group (n = 21) received regular chow. During and after the treatment period the dams showed reduced body weight and slower body weight gain, even with no change in food and water intake, evidencing mild maternal toxicity. Gestation was not significantly impaired, although experimental fetuses presented reduced body length at birth. Also, 20% of the treated dams showed one or two dead pups at birth. On day 22 of gestation and on post‐natal day 1, the levels of metabolites of the sex hormones oestradiol, progesterone and testosterone were measured in faeces by radioimmunoassay. On post‐natal day 1, tissue portions from the dams were collected for histopathological evaluation. No alterations were detected in either study. The results suggest that S. lycocarpum fruit did not impair gestation, however, it did promote mild maternal toxicity and mild fetotoxic effects if ingested as a food source during the gestation period. This study has implications for pregnant women, who employ phytotherapeutic formulations under the impression that they are harmless. Copyright © 2007 John Wiley & Sons, Ltd.
Efficient MPC optimization using Pontryagin's minimum principle
Authors: Cannon Mark , Liao Weiheng , Kouvaritakis Basil
Published: July 2007

A method of solving the online optimization in model predictive control (MPC) of input‐constrained linear systems is described. Using Pontryagin's minimum principle, the matrix factorizations performed by general purpose quadratic programming (QP) solvers are replaced by recursions of state and co‐state variables over the MPC prediction horizon. This allows for the derivation of solvers with computational complexity per iteration that depends only linearly on the length of the prediction horizon. Parameterizing predicted input and state variables in terms of the terminal predicted state results in low computational complexity but can lead to numerical sensitivity in predictions. To avoid ill‐conditioning an alternative parameterization is derived using Riccati recursions. Comparisons are drawn with the multiparametric QP solution, and the computational savings are demonstrated over generic QP solvers. Copyright © 2007 John Wiley & Sons, Ltd.
Supplemental water releases for fisheries restoration in a Brazilian floodplain river: a conceptual model
Authors: Godinho Alexandre L. , Kynard Boyd , Martinez Carlos B.
Published: July 2007

Highly productive floodplain rivers in Brazil and elsewhere provide livelihood and recreational fishing for millions of people around the world, but damming and controlled water discharge are a threat to these valuable ecosystems. Supplemental water releases (SWRs) at a dam are increasingly used for restoring fisheries productivity in many floodplain rivers. We proposed a conceptual model for a hypothetical water release to enhance fisheries using Três Marias Reservoir (TMR) on the São Francisco River (SFR), Brazil. The information needed by the model follows: (i) Biologically, what is the best release date? (ii) How much water will be released? (iii) What is the pattern of impoundment and how much impounded water will be released? (iv) What is the lost revenue to the power plant associated with SWR? (v) What is the relationship between river discharge and the area of floodplain that is flooded? (vi) What is the relationship between SWR and fisheries value? Ichthyoplankton studies in the SFR showed a clear positive relationship between fish density and water level (WL). While the relationship between WL and floodplain area flooded and recruitment is not known, we concluded the best date for release is when there is a natural flood, which naturally triggers fish spawning and the SWR will add to the natural flood and cover a greater floodplain area. The released volume will range from 0.302 km3 to 2.192 km3, depending on SWR duration. In most years from 1976 to 2003, TMR impounded enough water for SWR only in the second half of the fish‐spawning season (January–March). Lost revenue at TMR depended on release volume and ranged from US$ 0.493 million to US$ 3.452 million for the actual power rate. However, SWR could increase commercial fisheries income an estimated US$ 4.468 million. We forecast that SWR can bring fisheries benefits that surpass the lost revenue. Published in 2007 by John Wiley & Sons, Ltd.
Fluid therapy in acute large area burns: A system dynamics model
Authors: Bush James W. , Schneider Alan M. , Wachtel Thomas L. , Brimm John E.
Published: July 2007

A preliminary mathematical model of fluid dynamics in acute large area burns at present incorporates plasma water, urine output, burn water loss, insensible losses via the nonburned skin, lungs, and GI tract, as well as inputs of maintenance water and therapeutic (Brooke formula) fluids. The model is an initial step in a longer‐term project to identify the pathogenetic mechanisms that control fluid shifts and to evaluate the effects of crystalloid (sodium ion), colloid (albumin), and other guidelines for fluid resuscitation. The model is initialized in homeodynamic equilibrium for a standard 70‐kg person and gives reasonable, realistic responses to a wide range of parameter variations (body sizes, burn wound loss factors), step functions (burn size, discontinuation of maintenance water), and rates of therapeutic fluid administration, given its present structure. The addition of burn and nonburn interstitial and intracellular spaces and their constituents (water, sodium, albumin, and potassium) will (1) permit validation against a wide range of clinical and experimental data, (2) suggest refinements of current resuscitation guidelines, (3) suggest more incisive research on pathogenetic mechanisms and treatment modalities, and (4) permit comparison of system dynamics with alternative modeling and simulation approaches.
The world hunger problem: Do we really understand it?
Authors: Saeed Khalid
Published: July 2007

In this section the System Dynamics Review presents problems having the potential to stimulate system dynamics research. Articles may address real‐world dynamic problems that could be approached fruitfully from the system dynamics perspective, or methodological problems affecting the field. A paper submitted to the Research Problems section should concisely motivate and define a problem and start a process of conceptualization or formulation that can open the way for further studies. Manuscripts not exceeding 2,000 words should be sent to George P. Richardson, Department of Mathematics and Computer Science, Wheaton College, Norton, MA 02766, U.S.A.
A mathematical model to analyze predation and competition problems in a sheep‐farming region
Authors: Swart Johan , Hearne John W.
Published: July 2007

Sheep farmers in the Cape Midlands region of South Africa frequently sustain stock losses through predation by caracal lynx. Further losses are incurred because of hyrax competing with the sheep for pasture. As hyrax constitute the principal food of lynx, culling either hyrax or lynx has complex feedback effects.

A system dynamics model of this system comprising sheep, hyrax, lynx, pasture, and revenue sectors has been formulated. The model is used to simulate the system under different culling strategies.

By comparing stock positions and farming revenue generated over a number of years under different culling strategies, an optimal culling policy is determined using an optimization procedure. A parameter sensitivity analysis reveals that the policy recommendations are relatively insensitive to parameter uncertainty.
The spread of '88 Shanghai type‐A hepatitis: A system dynamics model and analysis
Authors: Su Mao‐Kang , Chen Keh‐Hsun , Wang Huan‐Chen
Published: July 2007

This articie examines a general infectious disease model and proposes a new epidemic threshold and an epidemic scale forecasting formula. Then a system dynamics model of an eruptive Spread of type‐A hepatitis in Shanghai in 1988 is presented. Various problems are resolved: simulating the incubation period of type‐A hepatitis; fitting the simulation results to real data; analyzing the reason that the predicted second peak of the eruptive spread did not occur. Short‐and long‐term prospects for recurrence are considered, especially the mechanisms of periodic epidemics and eruptive spreads of type‐A hepatitis. The results of this study have import for the prevention and control of type‐A hepatitis and other infectious diseases.
Dyadic processes, tempestuous relationships, and system dynamics
Authors: Radzicki Michael J.
Published: July 2007

Notes and Insights is a forum for discussion and debate about current issues in the philosophy and application of the system dynamics approach, and a marketplace for the exchange of information about currant research, policy issues, and teaching experiences. Manuscripts treating material particularly suited to presentation in short form (less than 2,000 words) should be sent to Erich Zahn, Betriebswirtschaft‐liches Institut, Abt. IV, Universität Stuttgart, Keplerstr. 17, D‐7000 Stuttgart 1, Germany.
Systems thinking: Critical thinking skills for the 1990s and beyond
Authors: Richmond Barry
Published: July 2007

The problems we face at all levels in the world today resist unilateral solutions. While the web of interdependencies tightens, our capacity for thinking in terms of dynamic interdependencies has not kept pace. As the gap between the nature of our problems and the ability to understand them grows, we face increasing perils on a multitude of fronts. Systems thinking and one of its subsets‐system dynamics‐are important for developing effective strategies to close this gap. Unfortunately, system dynamicists and systems thinkers have not effectively taught their framework, skills, and technologies to others. The door has not been opened wide enough to let others share our insights with respect to the workings of closed‐loop systems. To transfer this understanding on a broad scale, we need a clearer view of its nature and of the education system into which it must be transferred. This article casts some light on what we have to bestow and on the education system that is to receive our bounty. Its intended audience is both system thinkers and educators, and the hope is to help eradicate the distinction between the two.
Fuzzy system dynamics: An approach to vague and qualitative variables in simulation
Authors: Tessem Bjørnar , Davidsen Pål I.
Published: July 2007

The application of fuzzy numbers is suggested as an alternative to probabilistic methods for the management of uncertainty and vagueness in system dynamics models. Fuzzy numbers are particularly well suited for representing qualitative values and are used during simulation. To handle interaction among variables, we utilize global optimization methods. In nonlinear models, however, our implementation does not suffice. We illustrate the use of fuzzy numbers, qualitative values, and the problems of implementation by some simple examples.
Systems thinking and thinking systems
Authors: Ackoff Russell L.
Published: July 2007

Three types of system are identified and differentiated: mechanical, organismic, and social systems. The evolution of our concept of an enterprise from mechanical to social is then traced, as enterprises are viewed from each of these perspectives. Some consequences of conceptualizing them as social systems are then discussed, including the consequences of (1) considering the parts of an enterprise separately, as is commonly done, that is, managing analytically versus synthetically; (2) supervising personnel who can do their jobs better than their bosses; (3) treating problems separately rather than systemically, and (4) taking disciplines as aspects of reality, that is, as categories of nature.
Critical systems thinking: Beyond the fragments
Authors: Jackson Mike C.
Published: July 2007

This article is concerned with systems thinking as an approach to the management of complex problems. I argue that systems thinking is currently failing to make the most of the significant steps forward taken in the discipline during the 1970s and 1980s. Systems thinking should be able to present itself as the discipline capable of offering a holistic response to a very wide range of management problems. Instead, different groupings of academics and practitioners lay claim to the systems label but share little overall intellectual vision. While the discipline remains fragmented, the claim to offer a holistic and comprehensive response to management problems will seem hollow. Critical systems thinking is suggested as a way for the discipline to progress beyond the fragmentation.
Terminal conditions in system dynamics
Authors: Kivijärvi Hannu , Soismaa Margareta
Published: July 2007

When developing system dynamics models, particularly in economics and finance, we have repeatedly encountered requirements to analyze terminal conditions. We believe that this holds more generally for modeling social problems, too. In this article, we show how to solve system dynamics models when some level variables have predetermined terminal conditions. With the method presented, it is possible to determine consistently the initial states of the level variables given the terminal state conditions.
Measurement of fetal urine production by three‐dimensional ultrasonography in normal pregnancy
Authors: Lee S. M. , Park S. K. , Shim S. S. , Jun J. K. , Park J. S. , Syn H. C.
Published: July 2007

Objectives

Measurement of fetal urine production may provide a means of evaluating amniotic fluid volume, which is difficult to measure directly, and predicting fetal hypoxia. Although there have been some reports on fetal urine production, most of these have used two‐dimensional (2D) ultrasonography to measure bladder volume. Three‐dimensional (3D) ultrasonography is, however, known to be superior to 2D ultrasonography in some organ volume measurements. Thus, we undertook this study to measure bladder volumes using 3D ultrasonography and to establish a nomogram of fetal urine production rate (UPR) according to gestational age (GA).

Methods

One hundred and fifty‐four women with a normal singleton pregnancy at 24 to 40 weeks' gestation were enrolled in this cross‐sectional study. The women had no medical or obstetric complications affecting amniotic fluid volume. Fetal bladder volume was measured using 3D ultrasound imaging and Virtual Organ Computer‐aided AnaLysis (VOCAL) with a rotational angle of 30 degrees and manual surface tracing technique. Bladder volume was measured two or three times within a 5–10‐min interval and fetal UPR was calculated from serial measurements. When measurements were performed more than twice, we used the mean rate of calculated UPRs. UPR was then plotted against GA to establish the nomogram.

Results

Fetal UPR increased with GA from a median value of 7.3 mL/h at 24 weeks' gestation to 71.4 mL/h at term, and could be calculated from GA using the formula: Ln(UPR) = − 6.29582 + (0.43924 × GA) + (0.000432 × GA2), r2 = 0.63, P = 0.0046. Growth percentiles of UPR according to age are presented.

Conclusions

Fetal UPR can be easily measured by 3D ultrasound assessment of bladder volume. This modality may be a promising alternative to conventional methods of amniotic fluid volume measurement such as amniotic fluid index and single deepest pocket, and might be an alternative option for predicting fetal hypoxia. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Timing of subduction zone metamorphism during the formation and emplacement of Troodos and Baer–Bassit ophiolites: insights from 40Ar–39Ar geochronology
Authors: CHAN GAVIN HEUNG-NGAI , MALPAS JOHN , XENOPHONTOS COSTAS , LO CHING-HUA
Published: July 2007

The Troodos ophiolite in Cyprus and Baer–Bassit ophiolite in Syria together form part of the Tethyan ophiolite belt. They were generated in a supra-subduction zone setting in Late Cretaceous times. As with many of the ophiolite occurrences in this belt, the sequences are closely associated with tectonic ‘coloured mélange’ zones, which contain, among a variety of lithologies, metre- to kilometre-size blocks of metamorphic rocks. Precise 40Ar–39Ar laser step-heating experiments performed on four amphibolites from SW Cyprus and six from NW Syria, yield plateau ages ranging from 75.7±0.3 Ma to 88.9±0.8 Ma in Cyprus and 71.7±0.5 to 88.4±0.4 Ma in Syria. The older limits of these time spans are coeval with the age of the formation of the associated ophiolites. Unlike other metamorphic sole rocks which seem to form in relatively short time spans, these metamorphic rocks found in Cyprus and Syria are interpreted to have formed in Late Cretaceous times by accretion below the overriding Troodos and Baer–Bassit crust for a period of 15–18 Ma. The metamorphic complexes were exhumed by extension and crustal thinning associated with subduction roll-back and the rotation of the overriding plate until the cessation of subduction in Maastrichtian times. In Cyprus, the exhumed metamorphic complex was incorporated into an accretionary prism constructed primarily of the collapsed Mamonia passive margin sequence intercalated with rocks of the Troodos ophiolite during plate collision in the Maastrichtian. Concomitantly, in Syria, the Baer–Bassit ophiolite and subcreted metamorphic complex were emplaced onto the Arabian passive margin and fragmented into blocks and knockers, forming the Baer–Bassit mélange.
Admissible solutions for a class of nonlinear parabolic problems with non-negative data
Authors: Feireisl Eduard , Petzeltová Hana , Simondon Frédérique
Published: July 2007

We define a new class of admissible solutions for the parabolic problems where the theory of viscosity solutions does not apply. A typical example is the porous medium equation complemented by lower-order terms, nonlinear with respect to the gradient. In the case, the nonlinearity in the equation fails to be proper in the sense of the theory of viscosity solutions. The admissible solutions satisfy a very general comparison principle and, consequently, the corresponding initial-boundary value problems are well-posed in this class. They coincide with the standard viscosity solutions provided the nonlinearity in the equation is proper.
Solutions and multiple solutions for quasilinear hemivariational inequalities at resonance
Authors: Gasiński Leszek , Papageorgiou Nikolaos S.
Published: July 2007

In this paper we consider quasilinear hemivariational inequalities at resonance. We obtain existence theorems using Landesman-Lazer-type conditions and multiplicity theorems for problems with strong resonance at infinity. Our method of proof is based on the non-smooth critical point theory for locally Lipschitz functions and on a generalized version of the Ekeland variational principle.
On a conjecture of Fuchs
Authors: Miles Joseph , Rossi John
Published: July 2007

If f is an entire function of order ρ, 0 < ρ < 2−11, it is shown that the Nevanlinna deficiency d(0, f′/f) of the logarithmic derivative of f satisfies

For small positive ρ, this result strengthens an earlier estimate of Eremenko et al. concerning a conjecture of Fuchs.
Resonance and non-resonance in terms of average values. II
Authors: Nkashama M. N. , Robinson S. B.
Published: July 2007

We prove existence results for semilinear elliptic boundary-value problems in both the resonance and non-resonance cases. What sets our results apart is that we impose sufficient conditions for solvability in terms of the (asymptotic) average values of the nonlinearities, thus allowing the nonlinear term to have significant oscillations outside the given spectral gap as long as it remains within the interval on the average in some sense. This work generalizes the results of a previous paper, which dealt exclusively with the ordinary differential equation (ODE) case and relied on ODE techniques.
Decay measures on locally compact abelian topological groups
Authors: Antoniou I. , Shkarin S. A.
Published: July 2007

We show that the Banach space M of regular σ-additive finite Borel complex-valued measures on a non-discrete locally compact Hausdorff topological Abelian group is the direct sum of two linear closed subspaces MD and MND, where MD is the set of measures μ ∈ M whose Fourier transform vanishes at infinity and MND is the set of measures μ ∈ M such that ν ∉ MD for any ν ∈ M {0} absolutely continuous with respect to the variation |μ|. For any corresponding decomposition μ = μD + μND (μD ∈ MD and μND ∈ MND) there exist a Borel set A = A(μ) such that μD is the restriction of μ to A, therefore the measures μD and μND are singular with respect to each other. The measures μD and μND are real if μ is real and positive if μ is positive. In the case of singular continuous measures we have a refinement of Jordan's decomposition theorem. We provide series of examples of different behaviour of convolutions of measures from MD and MND.
Boundary-value problems in the Fanno model for turbulent compressible flow
Authors: Hastings S. P. , McLeod J. B. , Troy W. C.
Published: July 2007

A recent paper of Ockendon et al. discusses the Fanno model for quasi-one-dimensional flow of gas in a tube, in situations where the flow is turbulent and the tube is long enough for wall drag to be important. Based on appropriate scalings and with associated boundary conditions they derive equations for similarity solutions and make predictions about travelling and evolving waves. In this paper the existence, uniqueness and asymptotic behaviour of these wave forms is proved rigorously. Techniques include shooting methods (both one- and two-parameter), appropriate changes of variables, and comparison techniques.
Perturbation of eigenvalues embedded at a threshold
Authors: Jensen A. , Melgaard M.
Published: July 2007

Results are obtained on perturbation of eigenvalues and half-bound states (zero-resonances) embedded at a threshold. The results are obtained in a two-channel framework for small off-diagonal perturbations. The results are based on given asymptotic expansions of the component Hamiltonians.
Existence of a weak solution for the semigeostrophic equation with integrable initial data
Authors: Filho M. C. Lopes , Lopes H. J. Nussenzveig
Published: July 2007

In this article we present a proof of existence of a weak solution for the semigeostrophic system of equations, formulated as an active scalar transport equation with Monge-Ampère coupling, with initial data in . This is an extension of a 1998 result due to Benamou and Brenier, who proved existence with initial data in .
Subexponential solutions of linear integro-differential equations and transient renewal equations
Authors: Appleby John A. D. , Reynolds David W.
Published: July 2007

This paper studies the asymptotic behaviour of the solutions of the scalar integro-differential equation

The kernel k is assumed to be positive, continuous and integrable.If

it is known that all solutions x are integrable and x(t) → 0 as t → ∞, but also that x = 0 cannot be exponentially asymptotically stable unless there is some γ > 0 such that

Here, we restrict the kernel to be in a class of subexponential functions in which k(t) → 0 as t → ∞ so slowly that the above condition is violated. It is proved here that the rate of convergence of x(t) → 0 as t → ∞ is given by

The result is proved by determining the asymptotic behaviour of the solution of the transient renewal equation

If the kernel h is subexponential, then
In-plane displacements in thin-film blistering
Authors: Jin Weimin , Sternberg Peter
Published: July 2007

We consider the behaviour of buckling-driven thin-film blisterings using Von Karman's plate theory. Our results are asymptotic in the thinness and emphasize the incorporation of in-plane displacements in the model, a factor often ignored in the literature. Our work indicates that the inclusion of these displacements has a profound effect on the nature of solutions. We compare different constraints on displacements by estimating the leading order of corresponding energies. Our results strongly suggest that branching and other fine-scale structures arise in thin-film blistering, as has been observed in experiments.
On the flat ridges of submanifolds of codimension 2 in Rn
Authors: Romero-Fuster M. C. , Sanabria-Codesal E.
Published: July 2007

We introduce the concept of flat ridges for submanifolds of codimension 2 from the viewpoint of their contact with hyperplanes. We characterize them geometrically, studying some of their properties. In particular, we see that the highest-order flat ridges coincide with the flattenings of the asymptotic lines and from this we obtain some lower bounds for their numbers under appropriate conditions.
On the decay properties of solutions to the non-stationary Navier-Stokes equations in ℝ3
Authors: He Cheng , Xin Zhouping
Published: July 2007

In this paper, we study the asymptotic decay properties in both spatial and temporal variables for a class of weak and strong solutions, by constructing the weak and strong solutions in corresponding weighted spaces. It is shown that, for the strong solution, the rate of temporal decay depends on the rate of spatial decay of the initial data. Such rates of decay are optimal.
Geographical structure of dengue transmission and its determinants in Thailand
Authors: NAGAO Y. , SVASTI P. , TAWATSIN A. , THAVARA U.
Published: July 2007

Expansion of dengue has been attributed to urbanization. To test this concept, we examined dengue transmission intensities in Thailand. We used the inverse of mean age of dengue haemorrhagic fever (DHF) cases as a surrogate of dengue transmission intensity (or force of infection). The transmission intensity in Bangkok decreased rapidly since the mid-1990s, to levels that are currently lower than in other regions. Regression analysis revealed that transmission intensity is highest in the Northeastern rural region, mainly due to scarcity of private water wells. Private wells reduce the need for household water containers, the major breeding sites for vectors. Cumulatively, these results show that urbanization is not necessarily associated with intense dengue transmission in Thailand. Paradoxically, the DHF incidence in Bangkok has surpassed other regions despite declines in transmission intensity. This finding implies the existence of endemic stability (i.e. low incidence of a clinical illness in spite of high transmission intensity).
Using SIM for Double Star Astronomy
Authors: Shao Michael
Published: July 2007

The SIM (Planet Quest) mission is a space-based long-baseline stellar interferometer designed for ultra-precise astrometry. This paper describes how SIM can be used for double star research. There are several regimes of operation. For binary stars separated by more than 1″.5, SIM treats these as distinct objects. Double stars less than ∼10 milliarcsec in separation are seen as a single object and SIM measures the photocenter of the composite object. Between 10 mas and 1″.15, SIM is able to see the double star as two distinct objects, but because photons from both stars are detected there is the possibility of increased noise and measurement bias. This paper describes how double stars are observed with SIM and what information can be derived.
Modern Analysis Techniques for Spectroscopic Binaries
Authors: Hensberge Herman , Pavlovski Krešimir
Published: July 2007

Techniques to extract information from spectra of unresolved multi-component systems are revised, with emphasis on recent developments and practical aspects. We review the cross-correlation techniques developed to deal with such spectra, discuss the determination of the broadening function and compare techniques to reconstruct component spectra. The recent results obtained by separating or disentangling the component spectra is summarised. An evaluation is made of possible indeterminacies and random and systematic errors in the component spectra.
Detecting Chromospheric Activity on the Secondary Star of Cataclysmic Variables
Authors: Kafka Styliani
Published: July 2007

Chromospheric activity on the secondary stars of cataclysmic variables (CVs) is a key ingredient for angular momentum loss from the system via magnetic braking. This effect is thought to drive the evolution of the system and is invoked to explain a number of observed properties of CV light curves, such as long-term modulations and high/low states. However, obtaining observational support for magnetic activity has proven difficult. We present a new method of studying chromospheric activity on the secondary stars of CVs, using near-IR spectral features. We discuss in particular the magnetic CV AM Herculis, in which satellites to the H-alpha emission line are interpreted as arising from magnetically confined gas streams (prominences). This phenomenon provides a new technique for mapping magnetic structures on CV secondaries, and advances our understanding of the nature of magnetic structures and activity on CV secondaries.
The Apsidal Motion Test in Eclipsing Binaries
Authors: Giménez Alvaro
Published: July 2007

The use of eccentric eclipsing binaries to test stellar internal structure models, as well as the equations of motion provided by General Relativity, is reviewed. Close to 80 years have elapsed since the first ideas were produced in this field and many results have been obtained since then. It appears that, in general, a good understanding of stellar structure within the main sequence is available while the same level of knowledge can not be claimed beyond the termination age. The equations of general relativity could not be disproved with observational data though some systems cannot still be fully explained. In the near future, the analysis of evolved systems, very low mass stars, the effects of tidal resonances and the presence of third bodies has to be further explored. In addition, the analysis of large data bases obtained by means of extensive photometric surveys will certainly change the picture from an observational point of view.
The Sun's Smaller Cousins are Running the Universe — The Masses of Red and Brown Dwarfs
Authors: Henry Todd J.
Published: July 2007

Although not one red dwarf can be seen with the naked eye, they dominate the solar neighborhood, accounting for no less than 70% of all stars. The large numbers of these wee denizens of the night actually translate into a surprisingly large amount of mass – in fact, more mass is found in M dwarfs than in any other stellar spectral type.

To determine just how important red dwarfs are to the nature of the Universe, an accurate mass-luminosity relation (MLR) must be determined so that a relatively easily determined characteristic, luminosity, can be converted into the critical parameter, mass. Results from a decade-long observational effort to calibrate the MLR for red dwarfs using the Fine Guidance Sensors (FGSs) on the Hubble Space Telescope (HST) will be highlighted. For many of the binary systems targeted, the interferometric data from HST are combined with radial velocity data to further improve the mass measurements, which often have errors less than 5%. Related results from a large southern sky parallax program to determine accurate distances to red dwarfs, and a search for companions orbiting them, will also be discussed.

The state of mass determinations for M dwarfs' smaller cousins, the L and T dwarfs, will also be reviewed. Although we do not yet know the size of the true population of these (primarily) substellar objects, only by mapping out the interplay of their masses and luminosities (which change drastically with time) can we understand their contribution to the mass budget of the Universe.
U Geminorum: a Test Case for Orbital Parameters Determination
Authors: Echevarría Juan , de la Fuente Eduardo , Costero Rafael
Published: July 2007

High-resolution spectroscopy of U Gem was obtained during quiescence. We did not find a hot spot or gas stream around the outer boundaries of the accretion disk. Instead, we detected a strong narrow emission near the location of the secondary star. We measured the radial velocity curve from the wings of the double-peaked Hα emission line, and obtained a semi-amplitude value in excellent agreement with the ultraviolet results by Long & Gilliland (1999). We present also a new method to obtain K2, which enhances the detection of absorption or emission features arising in the late-type companion. Our results are compared with published values derived from the near-infrared NaI line doublet. From a comparison of the TiO band with those of late type M stars, we find that a best fit is obtained for a M6 V star, contributing 5% of the total light at that spectral region. Assuming that the radial velocity semi-amplitudes reflect accurately the motion of the binary components, then from our results: Kem = 108 ± 2 km s−1; Kabs = 310 ± 5 km s−1, and using the inclination angle by Zhang & Robinson (1987); i = 69°.7 ± 0.7, the system parameters become: MWD = 1.20 ± 0.05 M⊙; MRD = 0.42 ± 0.04 M⊙; and a = 1.55 ± 0.02 R⊙. Based on the separation of the double emission peaks, we calculate an outer disk radius of Rout/a ∼ 0.63, close to the distance of the inner Lagrangian point L1/a ∼ 0.63. Therefore we suggest that, at the time of observations, the accretion disk was filling the Roche-Lobe of the primary, and that the matter leaving the L1 point was colliding with the disc directly, producing the hot spot at this location. Specific details not included in the printed version can be found in the Electronic Poster (EP).
Observed Orbital Eccentricities
Authors: Abt Helmut A.
Published: July 2007

The eccentricities of catalogued binaries show that tidal interactions extend to periods of at least 1000 days. The maximum periods for complete circularization probably depend on age, rather than mass. For the longest periods all eccentricities are equally probable. For shorter periods the highest eccentricities disappear first. For the same periods, the SB2's have larger mean eccentricities than the SB1's, in accord with Keplers Third Law.
Asteroseismology of Close Binary Stars
Authors: Aerts Conny
Published: July 2007

In this review paper, we summarise the goals of asteroseismic studies of close binary stars. We first briefly recall the basic principles of asteroseismology, and highlight how the binarity of a star can be an asset, but also a complication, for the interpretation of the stellar oscillations. We discuss a few sample studies of pulsations in close binaries and summarise some case studies. This leads us to conclude that asteroseismology of close binaries is a challenging field of research, but with large potential for the improvement of current stellar structure theory. Finally, we highlight the best observing strategy to make efficient progress in the near future.
Discovery of Four β Cephei Stars in Eclipsing Systems
Authors: Pigulski Andrzej , Pojmański Grzegorz
Published: July 2007

Using the ASAS-3 photometry, we find the components of four eclipsing binary systems — V916 Cen, HD 101838, V4386 Sgr and HD 168050 — to be β Cephei-type pulsators. The first two systems are members of the young open cluster Stock 14. The pulsating stars are presumably the primary, more massive components in all these systems. The components are detached and for at least two systems, V916 Cen and HD 168050, we may suspect that they will appear to be double-lined spectroscopic ones. In consequence, these stars become very attractive targets for studying pulsations in β Cephei stars by means of asteroseismology.
Applied Binarology: Theoretical Aspects
Authors: Trimble Virginia
Published: July 2007

The winding up of a conference like this provides the opportunity to look (1) backwards at how we reached the present stage of understanding of binary star behavior and its relationship to the rest of astronomy, (2) around at the garden of unsolved problems, and (3) cautiously forward at what might come next.
New paleomagnetic age constraints on the Decaturville impact structure and Weaubleau structure along the 38th parallel in Missouri (North America)
Authors: Elmore R. D. , Dulin Shannon
Published: July 2007

Eight circular structures along the 38th parallel in the mid‐continent United States are hypothesized to have formed from multiple impacts. Only two of these structures have been confirmed as impact features and they are not well dated. In this study we use paleomagnetic data to constrain the timing of the poorly dated Decaturville impact structure (Missouri) and the Weaubleau feature (Missouri), interpreted to be an impact structure, to evaluate the possibility of a serial impact event. A post depositional, mid Permian pole derived from impact‐related breccias at Decaturville, as well as crosscutting relationships, show a Pennsylvanian‐mid Permian age for the structure. A post‐tilting Late Mississippian pole from deformed strata at Weaubleau indicates that the deformation event can be no younger than Late Mississippian. Our results demonstrate that the Decaturville and Weaubleau structures are of different ages and could not have been caused by a serial impact event.
Comparative microbiota ofRickettsia felis-uninfected and -infected colonized cat fleas,Ctenocephalides felis
Authors: Pornwiroon Walairat , Kearney Michael T , Husseneder Claudia , Foil Lane D , Macaluso Kevin R
Published: July 2007

Fleas serve as arthropod vectors for several emerging and re-emerging infectious disease causing agents including, Rickettsia felis. Although the prevalence of R. felis infection in colonies of fleas has been examined, the influence of the R. felis infection on flea microbiota has not been investigated. We identified three colonies of cat fleas, Ctenocephalides felis, with varying prevalence of R. felis infection (Louisiana State University (LSU), 93.8%; Professional Laboratory and Research Services Inc. (PLRS), 16.4%; Elward II (EL), 0%) and subsequently utilized polymerase chain reaction amplification, restriction fragment length polymorphism analysis and sequencing of the 1.4-kb portions of 16S rRNA genes to examine the diversity of bacteria in the flea populations. A total of 17 different bacterial 16S rRNA gene sequences were identified among the C. felis colonies. The prevalence of two Wolbachia species that were identified in each flea colony differed between colonies and R. felis-uninfected and -infected fleas. Species richness was unchanged among the R. felis-uninfected (LSU, PLRS and EL colonies) and -infected (LSU and PLRS colonies) fleas; however, between R. felis-uninfected and -infected fleas within both the LSU and PLRS colonies, R. felis-uninfected fleas have greater species richness. Diversity indices did not identify a difference in diversity between any of the flea samples. The interaction of endosymbionts within arthropods can widely impact the dissemination of vertically transmitted pathogenic bacteria; and the reciprocal may be true. These results suggest that carriage of R. felis has an impact on the richness of flea microbiota.
Multi-site precipitation downscaling via an expanded conditional density network
Authors: Cannon Alex
Published: July 2007

Statistical downscaling models are used to estimate weather data at a station or stations based on atmospheric circulation data defined at a coarser resolution, for example gridded outputs from a Global Climate Model (GCM). Downscaled data can be used as inputs to environmental models that require finer-scale climate fields than are currently available from GCMs. Maintaining realistic downscaling relationships between sites and variables is particularly important in hydrological models, as streamflow depends strongly on the spatial distribution of precipitation in a watershed and on interactions with temperature that determine whether precipitation falls as rain or snow. More generally, precipitation is a difficult variable to downscale because of its non-normal distribution and its spatial and temporal patchiness.A downscaling algorithm for daily precipitation series at multiple stations is presented. The expanded conditional density network (ECDN) models the conditional density of the Poisson-gamma distribution via an artificial neural network. ECDN is capable of (1) specifying the conditional distribution of precipitation at each site; (2) modeling occurrence and amount of precipitation simultaneously; (3) reproducing observed spatial relationships between sites; (4) randomly generating synthetic precipitation series; and (5) predicting precipitation amounts in excess of those in the observational record. The ECDN model is applied to two downscaling problems: the first is a benchmark precipitation downscaling task previously evaluated by other modeling groups; the second is a multi-site precipitation dataset from British Columbia, Canada. Results suggest that the ECDN approach is capable of generating spatially and temporally realistic precipitation series that are suitable for use as inputs to hydrological models or to spatial interpolation schemes.
Optical emission and mass spectrometric characterization of laser ablation process of Ca, Mg, and Ba at 1064nm
Authors: Cabanillas-Vidosa Iván , Rinaldi Carlos A. , Ferrero Juan C.
Published: July 2007

A systematic experimental study of the laser ablation of three alkaline-earth metals (Ca, Mg, and Ba) was carried out to understand the ablation processes of the metals. In this work the infrared laser ablation of alkaline-earth metals was studied by mass spectrometry together with the optical emission spectroscopy of the species generated in the ablation process. The analysis and modeling of the results were done using a heuristic equation that includes the Arrhenius, the screening, and the lineal regions that describe the three different regimes usually observed as a function of the laser fluence. We intend to prove that this equation depends on a fit surface parameter that includes the roughness surface, and it allows us to determine a critical fluence that can be related to the physical properties of the metal target.
Small-scale aspects of flows in proximity of the turbulent/nonturbulent interface
Authors: Holzner M. , Liberzon A. , Nikitin N. , Kinzelbach W. , Tsinober A.
Published: July 2007

The work reported below is the first of its kind to study the properties of turbulent flow without strong mean shear in a Newtonian fluid in proximity of the turbulent/nonturbulent interface, with emphasis on the small-scale aspects. The main tools used are a three-dimensional particle tracking system allowing one to measure and follow in a Lagrangian manner the field of velocity derivatives and direct numerical simulations. The comparison of flow properties in the turbulent (A), intermediate (B), and nonturbulent (C) regions in the proximity of the interface allows for direct observation of the key physical processes underlying the entrainment phenomenon. The differences between small-scale strain and enstrophy are striking and point to the definite scenario of turbulent entrainment via the viscous forces originating in strain.
Dynamic and temperature effects in toggle magnetic random access memory
Authors: Cimpoesu Dorin , Stancu Alexandru , Spinu Leonard
Published: July 2007

In this paper we have studied the dynamic switching in magnetic random access memory (MRAM) and its dependence on thermal effects due to a finite temperature. The model is based on the Landau-Lifshitz-Gilbert equation and the stochastic Landau-Lifshitz-Gilbert equation which are numerically integrated. The magnetic layers are assumed to be ellipsoid shaped with each magnetic layer single domain. In addition, we have taken into account the uniaxial intrinsic anisotropy. Simulations were performed for both balanced and nonbalanced synthetic antiferromagnetic elements. The switching properties are discussed as a function of applied field pulses’ length and shape. In this paper we present how the thermal fluctuations affect the switching behavior, the reliability, and the writing speed of MRAM devices.
Multistacked Al2O3∕HfO2∕SiO2 tunnel layer for high-density nonvolatile memory application
Authors: Chen Wei , Liu Wen-Jun , Zhang Min , Ding Shi-Jin , Zhang David Wei , Li Ming-Fu
Published: July 2007

A memory capacitor with a multistacked tunnel layer of Al2O3∕HfO2∕SiO2 (AHO) has been fabricated together with HfO2 charge trapping layer and Al2O3 control oxide layer. The resulting capacitor exhibits a memory window as large as 7.6V for ±12V sweep voltage range, a significant flatband voltage shift of 2.1V after 10V∕100μs programing as well as improved charge retention compared with a single SiO2 tunnel layer. The different memory effects in various sweep voltage ranges and enhanced retention characteristics have been explained based on the variable electrical thickness of the AHO stack under different electric fields.
Inhibition of Pin1 Reduces Glutamate-induced Perikaryal Accumulation of Phosphorylated Neurofilament-H in Neurons
Authors: Kesavapany Sashi , Patel Vyomesh , Zheng Ya-Li , Pareek Tej K. , Bjelogrlic Mia , Albers Wayne , Amin Niranjana , Jaffe Howard , Gutkind J. Silvio , Strong Michael J. , Grant Philip , Pant Harish C.
Published: July 2007

Under normal conditions, the proline-directed serine/threonine residues of neurofilament tail-domain repeats are exclusively phosphorylated in axons. In pathological conditions such as amyotrophic lateral sclerosis (ALS), motor neurons contain abnormal perikaryal accumulations of phosphorylated neurofilament proteins. The precise mechanisms for this compartment-specific phosphorylation of neurofilaments are not completely understood. Although localization of kinases and phosphatases is certainly implicated, another possibility involves Pin1 modulation of phosphorylation of the proline-directed serine/threonine residues. Pin1, a prolyl isomerase, selectively binds to phosphorylated proline-directed serine/threonine residues in target proteins and isomerizes cis isomers to more stable trans configurations. In this study we show that Pin1 associates with phosphorylated neurofilament-H (p-NF-H) in neurons and is colocalized in ALS-affected spinal cord neuronal inclusions. To mimic the pathology of neurodegeneration, we studied glutamate-stressed neurons that displayed increased p-NF-H in perikaryal accumulations that colocalized with Pin1 and led to cell death. Both effects were reduced upon inhibition of Pin1 activity by the use of an inhibitor juglone and down-regulating Pin1 levels through the use of Pin1 small interfering RNA. Thus, isomerization of lys-ser-pro repeat residues that are abundant in NF-H tail domains by Pin1 can regulate NF-H phosphorylation, which suggests that Pin1 inhibition may be an attractive therapeutic target to reduce pathological accumulations of p-NF-H.