bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Treatment on the Adsorption Capacity of Activated Carbon
Authors: Nouri Sirous 
Published: March 2003

The adsorption of p-cresol by three activated carbons, one untreated S.E.I. and the other two treated S.E.I., was carried out under controlled conditions. Such treatment led to a change in the point of zero charge (PZC) and the adsorption capacity (Qmax) of the carbon concerned. The adsorption capacity and affinity (K1) of each carbon was determined using the Langmuir homogeneous and binary models to compare the effects of different treatments on these and relative parameters. The variation of the model parameters with the solution pH was also studied. The fitted parameters obtained from both models showed the pH value had the most significant effect on the adsorption capacity (Qmax) and the adsorption affinity (K1) of a given carbon, with both quantities showing a decrease with increasing pH. It was found that the uptake of the molecular forms of the aromatic solute was dependent on the PZC of the carbons. Treatment with H2 increased the PZC whilst treatment with H2SO4 led to a decrease in this factor. At higher pH (when the solute was in an ionic form), it was found that electrostatic forces played a significant role on the extent of adsorption. Under these conditions, the adsorption of the solute depended on the concentration of its anionic form. It was shown that the effect of pH must be considered from the viewpoint of its combined effect on the carbon surface and on the solute molecules.
Dividend behavior surrounding LIFO adoption
Authors: Ettredge Michael , Youn Kim Jeong 
Published: March 2003

AbstractThis study investigates the influence of LIFO adoption on changes in cash dividends. Descriptive studies of dividend policy have found that changes in cash dividends are positively associated with both operating cash flows and accounting earnings. LIFO adoption is interesting because it typically decreases earnings while increasing cash flows through deferral of U.S. taxes. We regress changes in annual cash dividends against a proxy for the earnings effect and the cash flow effect of LIFO usage, as well as additional control variables. The model is estimated for each of five years, centered on the adoption year, using a sample of 361 LIFO adopters. The results suggest that adoption year changes in cash dividends are associated with the negative earnings effect rather than the positive cash flow effect of LIFO adoption.
Professional portfolio managers and the January effect: theory and evidence
Authors: Athanassakos George , Schnabel Jacques A. 
Published: March 2003

AbstractWhile many researchers have documented a pronounced seasonality of stock returns in the month of January, a universally accepted theory of why this so‐called “January effect” occurs has yet to be put forward. This paper develops a theory of portfolio rebalancing which is based on the effects induced by the calendar year planning horizon of professional portfolio managers. A simple model of portfolio choice and leisure consumption is developed via which it is shown that portfolio allocations early in the calendar year should be more heavily weighted towards the stock market and less heavily weighted towards cash and cash equivalents than later in the calendar year. The paper provides evidence on the impact systematic shifts in the portfolio holdings of institutional investors have had on the aggregate stock market in Canada over the period 1973:Q1 to 1992:Q4. It is shown that institutional trading actively influences stock price changes and that portfolio rebalancing on the part of professional fund managers, prompted by conflict‐of‐interest considerations, causes the bidding up of stock prices in January.
Rational price limits in futures markets: tests of a simple optimizing model
Authors: Ackert Lucy F. , Hunter William C. 
Published: March 2003

AbstractThis paper tests a simple descriptive model of optimal futures price limits under the assumption that futures exchanges operate under the criterion of minimizing the long‐run average cost associated with market making. This cost is composed of a “running cost,” reflecting the expenses associated with providing for the continuous operation of the market, and a cost associated with trading interruptions resulting from limit moves. The model implies that the optimal daily limit increases with the cost of trading interruptions and decreases with running costs and that at the margin, the limit should be set so as to just balance these costs. The model is tested using price limits in place on ten contracts traded on the Chicago Board of Trade between 1977 and 1979. The econometric results indicate that for seven of the ten contracts examined, the actual level of the daily price limit is, on average, equal to that implied by the optimizing model.
A millennial-scale record of Holocene tsunamis on the Kronotskiy Bay coast, Kamchatka, Russia
Authors: Pinegina Tatiana K. , Bourgeois Joanne , Bazanova Lilia I. , Melekestsev Ivan V. , Braitseva Olga A. 
Published: March 2003

AbstractDeposits from as many as 50 large tsunamis during the last 7000 years are preserved on the Pacific coast of the Kamchatka Peninsula near the mouth of the Zhupanova River, southern Kronotskiy Bay. These deposits are dated and correlated using Holocene marker tephra layers. The combined, preserved record of tsunami deposits and of numerous marker tephras on Kamchatka offers an unprecedented opportunity to study tsunami frequency. For example, from the stratigraphy along southern Kronotskiy Bay, we estimate frequency of large tsunamis (>5 m runup). In the last 3000 years, the minimum frequency is about one large tsunami per 100 years, and the maximum about one large tsunami per 30 years; the latter frequency occurred from about 0 to 1000 A.D. This time interval corresponds to a period of increased seismicity and volcanic activity that appears to be recorded in many places on the Kamchatka Peninsula.
Tree-ring dated landslide movements and their relationship to seismic events in southwestern Montana, USA
Authors: Carrara Paul E. , O’Neill J. Micheal 
Published: March 2003

AbstractTo determine periods of incremental landslide movement and their possible relationship to regional seismic events, the tree-ring records of 32 tilted and damaged conifers at three sites on landslides in the Gravelly Range of southwestern Montana were examined. Several signs of disturbance in the tree-ring record indicating landslide movement were observed. Commonly, the tree-ring record displayed a marked reduction in annual ring width and/or the reaction wood formation. The tree-ring records from the three landslide sites indicate multiple periods of movement during the 20th century. Many of the periods of movement indicated by the strongest signals (most trees) at the sites occurred the year following significant earthquakes in the region. Those seismic events for which evidence in the tree-ring record was found at one or more of the three sites are the 1983 Borah Peak, 1959 Hebgen Lake, 1935 Helena, 1925 Clarkson, and 1908 Virginia City earthquakes. This study suggests that many of the landslide movements were triggered by, or are coincident with, earthquakes as much as 200 km from the study area.
Phytolith assemblages as a promising tool for reconstructing Mediterranean Holocene vegetation
Authors: Delhon Claire , Alexandre Anne , Berger Jean-François , Thiébault Stéphanie , Brochier Jacques-Léopold , Meunier Jean-Dominique 
Published: March 2003

AbstractThe reliability of phytolith assemblage analysis for characterizing Mediterranean vegetation is investigated in this study. Phytolith assemblages are extracted from modern and buried Holocene soils from the middle Rhône valley (France). The relation between modern phytolith assemblages and the surrounding vegetation, as well as between fossil assemblages and contemporaneous vegetation, already reconstructed through other proxies, is discussed. We demonstrate that the main northwestern Mediterranean biomes are well distinguished by soil phytolith assemblage analysis. In particular, the density of pine and nonconiferous trees (densities expressed relatively to the grass cover) and the overall degree of opening of the vegetation appear well recorded by three phytolith indexes. North Mediterranean vegetation changes during the Holocene period, mainly tree line shifts, pine wood development and deforestation are poorly documented, due to the scarcity of proxy-preserving sites. Phytolith assemblage analysis of soils, buried soils, and sediments appears to be a promising technique to fill this gap.
Precise radiocarbon dating of Late-Glacial cooling in mid-latitude South America
Authors: Hajdas Irka , Bonani Georges , Moreno Patricio I. , Ariztegui Daniel 
Published: March 2003

AbstractVariability of atmospheric 14C content often complicates radiocarbon-based chronologies; however, specific features such as periods of constant 14C age or steep changes in radiocarbon ages can be useful stratigraphic markers. The Younger Dryas event in the Northern Hemisphere is one of those periods, showing conspicuous 14C wiggles. Although the origin of those variations is not fully understood, we can make practical use of them and determine: (i) whether the Younger Dryas was global in extent; if so, (ii) were the initial cooling and the final warming synchronous worldwide; and (iii) what are the implications of these similarities/differences? Here we report high-resolution AMS 14C chronologies from the mid-latitudes of South America that pinpoint a cool episode between 11,400 and 10,20014C yr B.P. The onset of the final cool episode of the Late Glacial in the southern mid-latitudes, i.e., the Huelmo/Mascardi Cold Reversal, preceded the onset of the Younger Dryas cold event by ∼550 calendar years. Both events ended during a radiocarbon-age plateau at ∼10,20014C yr B.P. Thus, the Huelmo/Mascardi Cold Reversal encompasses the Younger Dryas, as well as a couple of short-term cool/warm oscillations that immediately preceded its onset in the North Atlantic region.
Land–sea correlations for the last glaciation inferred from a pollen and dinocyst record from the Portuguese margin
Authors: Turon Jean-Louis , Lézine Anne-Marie , Denèfle Michelle 
Published: March 2003

AbstractPollen and dinoflagellate cyst assemblages from Core SU 81-18 recovered off Portugal (37°46′N, 10°11′W; 3135-m water depth) have been used to document the short-term environmental changes that occurred in southwest Europe since 25,000 yr B.P. The relationship between the oceanic and continental environments has been further examined by the use of other marine proxies (coarse sedimentary fraction, foraminifera) and by comparison with proximal land pollen records. Heinrich 2 (H2) and Heinrich 1 (H1) events were the most extreme parts of the highly variable last glacial period, with the maximum extension of dry steppe on land and the occurrence of cool and dilute waters at the core site. Our study shows that H1 and H2 are divided in two distinct phases: one with Neogloboquadrina pachyderma left coiling associated with the maximum input of ice rafted debris, reflecting the in situ release of icebergs and the occurrence of cool and dilute seawater at the core site; the other with dinoflagellate cysts of subpolar affinity, Bitectatodinium tepikiense, reflecting a seasonal control marked by warm summer SST and cold winter SST.
Regular self-similar solutions of the nonlinear heat equation with initial data above the singular steady state
Authors: Souplet Philippe , Weissler Fred B 
Published: March 2003

We prove the existence of positive regular solutions of the Cauchy problem for the nonlinear heat equation

u_t=Δu+|u|^αu

, with initial value

μV

, for all

μ>1

close enough to

1

, where

V

is the singular stationary solution in

\mathbb{R}^{N}

. This result is obtained when

N>2

and

\frac{2}{N - 2} < \alpha < \alpha^*

, where

α^∗

is the critical power for the intersection properties of

V

with regular stationary solutions. Moreover, for

μ

as above, there exist at least two positive regular solutions with initial value

μV

. These results are optimal since it is known that no such solution exists if

α≥α^∗

.

Résumé

Nous montrons l’existence de solutions positives régulières du problème de Cauchy pour l’équation de la chaleur non linéaire

u_t=Δu+|u|^αu

, avec donnée initiale

μV

, pour tout

μ>1

assez proche de

1

, où

V

est la solution stationnaire singulière dans

\mathbb{R}^{N}

. Ce résultat est obtenu pour

N>2

et

\frac{2}{N - 2} < \alpha < \alpha^*

, où

α^∗

est la puissance critique pour les propriétés d’intersection de

V

avec les solutions stationnaires régulières. De plus, pour

μ

comme ci-dessus, il existe au moins deux solutions positives régulières avec donnée initiale

μV

. Ces résultats sont optimaux, car on savait déjà que de telles solutions ne peuvent exister si

α≥α^∗

.
Almost continuous solutions of geometric Hamilton–Jacobi equations
Authors: Siconolfi Antonio 
Published: March 2003

We study the Hamilton–Jacobi equation

u_{t} + H\left(x,Du\right) = 0

in

R^{N} \times ] 0, + \infty[

, where

H

is a continuous positively homogeneous Hamiltonian with constant sign and verifying suitable assumptions but no convexity properties. We look for discontinuous (viscosity) solutions verifying certain initial conditions with discontinuous data. Our aim is to give representation formulae as well as uniqueness and stability results.

We find that the condition

\begin{matrix} \left(u^{\#}\right)_{\#} = u_{\#} & \text{and} & \left(u_{\#}\right)^{\#} = \\ \end{matrix}u^{\#}

where

u^\# (u_\#)

denotes the upper (lower) semicontinuous envelope of

u

, can be used as a uniqueness criterion and determines a class of solutions defined and continuous on certain dense subsets of

R^{N} \times ] 0, + \infty[

that we call almost continuous.

Such solutions can be represented by a formula which is a generalization of the Lax–Hopf one for the eikonal equation.

Résumé
Nous étudions l’équation de Hamilton–Jacobi

u_{t} + H\left(x,Du\right) = 0

en

R^{N} \times ] 0, + \infty[

, où

H

est un Hamiltomien continu et positivement homogène qui ne change pas de signe et qui ne vérifie aucune hypothèse de convexité. On cherche des solutions de viscosité discontinues qui vérifient certaines conditions initiales avec des données discontinues. Le but est de donner des formules de représentation aussi bien que des résultats d’unicité et de stabilité.

Nous prouvons que la condition

\begin{matrix} \left(u^{\#}\right)_{\#} = u_{\#} & \text{et} & \left(u_{\#}\right)^{\#} = \\ \end{matrix}u^{\#}

oú

u^\# (u_\#)

est l’enveloppe s.c.s. (s.c.i.) de

u

, peut être utilisée comme un critère d’unicité et détermine une classe de solutions définies et continues sur des ensembles denses de

R^{N} \times ] 0, + \infty[

que nous appellons presque continues.

Nous représentons ces solutions à l’aide d’une formule qui généralise celle de Lax–Hopf pour l’équation eiconale.
Critical groups computations on a class of Sobolev Banach spaces via Morse index
Authors: Vannella Giuseppina , Cingolani Silvia 
Published: March 2003

In this paper we deal with critical groups estimates for a functional

f:W_{0}^{1,p}\left(\Omega \right)\rightarrow \mathbb{R}\left(p > 2\right),\Omega

bounded domain of

\mathbb{R}^{N}

, defined by setting

f\left(u\right) = \frac{1}{p}\int \limits_{\Omega }\left|\nabla u\right|^{p}dx + \frac{1}{2}\int \limits_{\Omega }\left|\nabla u\right|^{2}dx\int \limits_{\Omega }G\left(u\right)dx

where

G\left(t\right) = \int _{0}^{t}g\left(s\right)ds

and

g

is a smooth real function on

ℝ

, growing subcritically. We remark that the second derivative of

f

in each critical point

u

is not a Fredholm operator from

W_{0}^{1,p}\left(\Omega \right)

to its dual space, so that the generalized Morse splitting lemma does not work. In spite of the lack of an Hilbert structure, we compute the critical groups of

f

in

u

via its Morse index.

Résumé

Dans cet article, nous estimons les groupes critiques pour une fonctionnelle :

f:W_{0}^{1,p}\left(\Omega \right)\rightarrow \mathbb{R}\left(p > 2\right),\Omega

ensemble borné de

\mathbb{R}^{N}

, définie par

f\left(u\right) = \frac{1}{p}\int \limits_{\Omega }\left|\nabla u\right|^{p}dx + \frac{1}{2}\int \limits_{\Omega }\left|\nabla u\right|^{2}dx\int \limits_{\Omega }G\left(u\right)dx

où

G\left(t\right) = \int _{0}^{t}g\left(s\right)ds

et

g

est une fonction réelle et régulière sur

ℝ

, avec une croissance sous-critique. On observe que la dérive seconde de

f

en chaque point

u

n’est pas un opérateur de Fredholm entre

W_{0}^{1,p}\left(\Omega \right)

est son espace dual et la généralisation du Lemme de Morse ne peut être appliquée. Bien que la structure d’espace d’Hilbert n’existe pas, on est capable de calculer les groupes critiques de

f

en

u

grâce à l’index de Morse.
Multiplicity of solutions for quasilinear elliptic problems involving critical Sobolev exponents
Authors: Silva Elves A.B , Xavier Magda S 
Published: March 2003

The main results of this paper establish, via the variational method, the multiplicity of solutions for quasilinear elliptic problems involving critical Sobolev exponents under the presence of symmetry. The concentration-compactness principle allows to prove that the Palais–Smale condition is satisfied below a certain level.

Résumé
Les résultats principaux de cet article établissent, via la méthode variationnelle, la multiplicité de solutions pour des problèmes elliptiques quasi-linéaires qui font intervenir l’exposant limite de Sobolev en présence de symétrie. La méthode de concentration-compacité permet de montrer que la condition de Palais–Smale est satisfaite au-dessous d’un certain niveau.
Long time averaged reflection force and homogenization of oscillating Neumann boundary conditions
Authors: Arisawa Mariko 
Published: March 2003

This paper concerns with two issues. The first issue is the existence and the uniqueness of the ergodic type number

d

which appears in the oblique boundary condition. The second issue is the application of the number for the study of homogenizations of oscillating Neumann boundary conditions.

Résumé

Dans cette article, nous traitons deux problèmes. Le premier est l’existence et l’unicité d’un nombre du type ergodique

d

qui apparaît dans la condition oblique sur le bord. Le second est l’application de ce nombre pour la recherche des homogénéizationses conditions Neumann sur des bords oscillants.
The initial phase of fracture healing is specifically sensitive to mechanical conditions
Authors: Klein Petra , Schell Hanna , Streitparth Florian , Heller Markus , Kassi Jean‐Pierre , Kandziora Frank , Bragulla Hermann , Haas Norbert P. , Duda Georg N. 
Published: March 2003

AbstractInterfragmentary movements affect the quality and quantity of callus formation. The mounting plane of monolateral external fixators may give direction to those movements. Therefore, the aim of this study was to determine the influence of the fixator mounting plane on the process of fracture healing.Identically configured fixators were mounted either medially or anteromedially on the tibiae of sheep. Interfragmentary movements and ground reaction forces were evaluated in vivo during a nine week period. Histomorphological and biomechanical parameters described the bone healing processes.Changing only the mounting plane led to a modification of interfragmentary movements in the initial healing phase. The difference in interfragmentary movements between the groups was only significant during the first post‐operative period. However, these initial differences in mechanical conditions influenced callus tissue formation significantly. The group with the anteromedially mounted fixator, initially showing significantly more interfragmentary movements, ended up with a significantly smaller callus diameter and a significantly higher callus stiffness as a result of advanced fracture healing. This demonstrates that the initial phase of healing is sensitive to mechanical conditions and influences the course of healing. Therefore, initial mechanical stability of an osteosynthesis should be considered an important factor in clinical fracture treatment. © 2003 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Proline induces oxidative stress in cerebral cortex of rats
Authors: Delwing Daniela , Bavaresco Caren S. , Wannmacher Clóvis M.D. , Wajner Moacir , Dutra‐Filho Carlos S. , Wyse Angela T.S. 
Published: March 2003

AbstractIn the present study we investigated the in vivo and in vitro effects of proline on some parameters of oxidative stress, such as chemiluminescence, total radical‐trapping antioxidant potential (TRAP) and the activity of the antioxidant enzymes catalase, glutathione peroxidase and superoxide dismutase in rat cerebral cortex. Ten‐day‐old rats received one subcutaneous injection of proline (12.8 μmol/g body weight), while control rats received saline in the same volumes. The animals were killed 1 h after injection, the cerebral cortex was isolated and the assays immediately carried out. For the in vitro studies, homogenates from cerebral cortex of 10‐day‐old untreated rats were incubated for 1 h at 37 °C with various concentrations of proline (3.0 μM–1.0 mM). Results showed that proline‐treated rats presented a decrease of TRAP (30%) and an increase of chemiluminescence (78%). In contrast, the activities of catalase, glutathione peroxidase and superoxide dismutase were not modified by proline acute treatment. Furthermore, the presence of proline in the medium increased chemiluminescence, decreased TRAP and the activity of superoxide dismutase at proline concentrations similar to those observed in tissues of hyperprolinemic patients (0.5–1.0 mM). However, catalase and glutathione peroxidase activities were not affected by the presence of proline in the medium. The results indicate that proline induces oxidative stress in the brain, which may be related, at least in part, to the neurological dysfunction observed in hyperprolinemia.
Localization of focal adhesion kinase isoforms in cells of the central nervous system
Authors: Contestabile Andrea , Bonanomi Dario , Burgaya Ferran , Girault Jean‐Antoine , Valtorta Flavia 
Published: March 2003

AbstractFocal adhesion kinase (FAK) is a non‐receptor tyrosine kinase which in non‐neuronal cells is localized to focal adhesions, where it participates to adhesion‐dependent intracellular signalling. FAK is highly expressed in the central nervous system both during development and in the adult. FAK+, a splice isoform of FAK selectively enriched in neurons, contains a three‐amino acid insertion in the carboxy‐terminal sequence responsible for the localization of FAK to focal adhesions. Enhanced green fluorescent protein‐tagged constructs were used to study the targeting of FAK and FAK+ in neuronal and non‐neuronal cells of the central nervous system. In transfected non‐neuronal cells, both fusion proteins colocalized with vinculin in focal contacts. When expressed in hippocampal neurons in culture, both chimeras were locally concentrated in the growth cone, where they overlapped with F‐actin enrichments but not with vinculin. In the growth cone of living neurons, the FAK+ chimera showed a dynamic relocalization to membrane ruffles and to the tips of the membrane protrusions induced by cytochalasin D treatment, indicating a dependence of FAK distribution on F‐actin organization. Since virtually identical patterns of distribution were found for FAK and FAK+ chimeras, it follows that the additional insertion in FAK+ is not responsible for the localization of the kinase. Finally, we showed that the carboxy‐terminal domain of both FAK and FAK+ is sufficient to mediate the localization of the proteins to focal adhesions in non‐neuronal cells and to maintain their correct intracellular targeting in neurons.