bluuebunny/crossref_metadata_2025_split huggingface dataset:
On critical exponents for the Pucci’s extremal operators
Authors: Felmer Patricio L. , Quaas Alexander 
Published: June 2003

In this article we study some results on the existence of radially symmetric, non-negative solutions for the nonlinear elliptic equation

\tag{$*$}
\mathcal M_{\lambda ,\Lambda }^{ + }\left(D^{2}u\right) + u^{P} = 0 \quad \text{in }\mathbb{R}^{N}.

Here

N⩾3

,

p>1

and

\mathcal M_{\lambda ,\Lambda }^{ + }

denotes the Pucci’s extremal operators with parameters

0<λ⩽Λ

. The goal is to describe the solution set in function of the parameter

p

. We find critical exponents

1 < p_{ + }^{*} < p_{ + }^{p}

that satisfy: (i) If

1 < p < p_{ + }^{*}

then there is no non-trivial radial solution of (

*

). (ii) If

p = p_{ + }^{*}

then there is a unique fast decaying radial solution of (

*

). (iii) If

p_{ + }^{*} < p \leq p_{ + }^{p}

then there is a unique pseudo-slow decaying radial solution to (

*

). (iv) If

p^p_+<p

then there is a unique slow decaying radial solution to (

*

). Similar results are obtained for the operator

\mathcal M_{\lambda ,\Lambda }^{ - }

.

Résumé
Dans cet article nous avons étudié quelques résultats d’existence des solutions radiales non négatives pour l’équation elliptique non linéaire

\tag{$*$}
\mathcal M_{\lambda ,\Lambda }^{ + }\left(D^{2}u\right) + u^{P} = 0 \quad u \geq 0 \text{ dans }\mathbb R^{N}.

Ici

N⩾3

,

p>1

et

\mathcal M_{\lambda ,\Lambda }^{ + }

est l’opérateur extrémal de Pucci avec les paramètres

0<λ⩽Λ

. L’objectif est de décrire l’ensemble des solutions en fonction de

p

. On trouve des exposants critiques

1 < p_{ + }^{*} < p_{ + }^{p}

tels que : (i) Si

1 < p < p_{ + }^{*}

, alors il n’existe pas de solution radiale non triviale de (

*

). (ii) Si

p = p^∗_+

, il existe une unique solution radiale de (

*

) à décroissance rapide. (iii) Si

p^*<p⩽p^p_+

, il existe une unique solution radiale de (

*

) à décroissance pseudo-lente. (iv) Si

p^p_+<p

, il existe une unique solution radiale de (

*

) à décroissance lente.

Un résultat similaire est obtenu pour l’opérateur

\mathcal M_{\lambda ,\Lambda }^{ - }

.
Permanence under strong aggressions is possible
Authors: Cano-Casanova Santiago , López-Gómez Julián 
Published: June 2003

This paper analyzes the limiting behavior of the positive solutions of a general class of sublinear elliptic weighted mixed boundary value problems as the amplitude of the positive part of the lower order terms of the differential operator blows up to infinity. The main result establishes that the positive solutions approximate zero within the support of the positive part of the potential, whereas they stabilize to the positive solution of a certain elliptic mixed boundary value problem on its complement. Further, we use this result for deriving some general principles in competing species dynamics. Precisely, we shall show that in the presence of a refuge region two competing species must coexist if their reproduction rates are sufficiently large, independently of the strength of the competition. It should be emphasized that the abstract theory developed here allows measuring how large the reproduction rates should be for being permanent, providing us, simultaneously, with the limiting behavior of each of the species separately. Basically, when the pressure from the competitor grows the tackled species concentrates within its refuge. The results of this paper are substantial extensions of some pioneer results found by one of the authors in [16, Section 4]. The main ingredients in deriving the main results of this paper are the continuous dependence of the principal eigenvalue with respect to a general class of perturbations of the domain around its Dirichlet boundary – very recent result coming from [6] – and the continuous dependence of the positive solutions of the sublinear problem – coming from [7].

Résumé
On étudie le comportement asymptotique des solutions positives d’une classe très générale de problèmes aux limites non linéaires elliptiques lorsque l’amplitude du potentiel d’ordre zéro de l’opérateur différentiel tend vers l’infini. En particulier, on verra que la solution tend vers zéro sur le support de la partie positive du potentiel, tandis qu’elle converge vers la solution positive d’un certain problème aux limites elliptiques auxiliaires sur la région ou le potentiel est nul. De plus, on va tirer de ce résultat de convergence un postulat biologique concernant la lutte pour la vie des espèces qui s’entredévorent : indépendamment de l’intensité des agressions, en présence d’un refuge pour chaque compétiteur les espèces coexistent si leurs coefficients d’accroissement sont assez longs. Il faut préciser qu’avec la théorie développée ici on peut mesurer le coefficient d’accroissement critique des espèces pour avoir la coexistence. Naturellement, l’espèce agressée va se concentrer sur les refuges correspondants si l’intensité des agressions croı̂t. Tous les résultats obtenus ici sont des généralisations substantielles des résultats [16, Section 4]. Pour démontrer ces résultats on utilise la dépendance continue de la première valeur propre, et de la solution positive même du problème aux limites non linéaire, par rapport aux perturbations du domaine (cf. [6] et [7]).
Distribution of in situ forces in the anterior cruciate ligament in response to rotatory loads
Authors: Gabriel Mary T. , Wong Eric K. , Woo Savio L‐Y. , Yagi Masayoshi , Debski Richard E. 
Published: June 2003

AbstractThe anterior cruciate ligament (ACL) can be anatomically divided into anteromedial (AM) and posterolateral (PL) bundles. Current ACL reconstruction techniques focus primarily on reproducing the AM bundle, but are insufficient in response to rotatory loads. The objective of this study was to determine the distribution of in situ force between the two bundles when the knee is subjected to anterior tibial and rotatory loads. Ten cadaveric knees (50 ± 10 years) were tested using a robotic/universal forcemoment sensor (UFS) testing system. Two external loading conditions were applied: a 134 N anterior tibial load at full knee extension and 15°, 30°, 60°, and 90° of flexion and a combined rotatory load of 10 N m valgus and 5 N m internal tibial torque at 15° and 30° of flexion. The resulting 6 degrees of freedom kinematics of the knee and the in situ forces in the ACL and its two bundles were determined. Under an anterior tibial load, the in situ force in the PL bundle was the highest at full extension (67 ± 30 N) and decreased with increasing flexion. The in situ force in the AM bundle was lower than in the PL bundle at full extension, but increased with increasing flexion, reaching a maximum (90 ± 17 N) at 60° of flexion and then decreasing at 90°. Under a combined rotatory load, the in situ force of the PL bundle was higher at 15° (21 ± 11 N) and lower at 30° of flexion (14 ± 6 N). The in situ force in the AM bundle was similar at 15° and 30° of knee flexion (30 ± 15 vs. 35 ± 16 N, respectively). Comparing these two external loading conditions demonstrated the importance of the PL bundle, especially when the knee is near full extension. These findings provide a better understanding of the function of the two bundles of the ACL and could serve as a basis for future considerations of surgical reconstruction in the replacement of the ACL. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Pre‐degenerated nerve shows enhanced regeneration after incremental elongation in rats
Authors: Hara Yuki , Tsujino Akihito , Abe Ichiro , Ichimura Harumitsu , Ochiai Naoyuki 
Published: June 2003

AbstractFollowing nerve degeneration, we investigated effects of linear elongation on subsequent nerve regeneration in a total of 92 Wistar rats (weight 380–340 g). The nerve was ligated at the midthigh and then elongated incrementally by a total of 15 mm by leg lengthening at a rate of 3 or 5 mm/day. Seven days after initiation of nerve elongation, the external fixator was removed and normal leg length was restored with internal fixation. Then a 10 mm nerve segment at the ligature site was excised, and the nerve was repaired with sutures (group D). At 2, 4, 6, and 8 weeks after nerve suturing, we examined transverse semi‐thin nerve sections compared with group I (severed and repaired after leg lengthening without a nerve ligature) and control group (severed and repaired without leg lengthening). After lengthening at 3 mm/day, nerve regeneration in group D was enhanced at 4 weeks. After lengthening at 5 mm/day, nerve regeneration in group D also was enhanced at 6 and 8 weeks. Pre‐degenerated nerve showed better regeneration after suturing than intact nerve. Elongation holds promise as an alternative to nerve grafting in treatment of nerve injury. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Evaluation of the absolute levels of acoustic estimates of the 1983 year class of Norwegian spring-spawning herring
Authors: Røttingen Ingolf , Tjelmeland Sigurd 
Published: June 2003

Abstract
The 1983 year class of Norwegian spring-spawning herring was large and, in retrospect, increased the spawning stock by more than two million tons when it recruited in 1987–1988. This paper summarizes and evaluates the acoustic estimates of the 1983 year class in the period 1983–2001. The key to the evaluation is a minimum stock based on the number of the 1983 year class caught in the international fishery and the year-class estimates made by the ICES Northern Pelagic and Blue Whiting Fisheries Working Group in 2002 using the SeaStar assessment model. The period of analysis covers a change in instrumentation, around 1990, from the SIMRAD EK400/Nord integrator to the EK500/BEI integrator system. The application of the acoustic estimates in the assessment and management of this herring stock is reviewed. It is concluded that the stock size was underestimated when the acoustic estimates were used in an absolute sense in the 1980s. In the 1990s the acoustic estimates were tuned to stock-size indices obtained from other methodologies and this approach seems to have given a realistic picture of the development of the 1983 year class.
Inferring fish orientation from broadband-acoustic echoes
Authors: Stanton Timothy K , Reeder D.Benjamin , Jech J.Michael 
Published: June 2003

Abstract
A new method has been developed for inferring the orientation of fish through the use of broadband-acoustic signals. The method takes advantage of the high range resolution of these signals, once temporally compressed through cross-correlation. The temporal resolution of these compressed signals is inversely proportional to the bandwidth, thus the greater the bandwidth the higher the resolution. This process has been applied to broadband-chirp signals spanning the frequency range 40–95 kHz to obtain a range resolution of approximately 2 cm from the original, unprocessed resolution of about 50 cm. With such high resolution, individual scattering features along the fish have been resolved, especially for angles well off normal incidence. The overall duration of the compressed echo from live, individual alewife, as measured in a laboratory tank, is shown to increase monotonically with orientation angle relative to normal incidence. The increase is due to the greater range separation relative to the transducer between the echoes from the head and tail of the fish. The results of this study show that with a priori knowledge of the length of the fish, the orientation could be estimated from the duration of a single, compressed broadband echo. This method applies to individual, acoustically resolved fish. It has advantages over previous approaches because it derives the orientation from a single ping and it does not use a formal, mathematical scattering model. Design parameters for applications in the ocean are given for a range of conditions and fish size.
Ex situ target strength of rockfish (Sebastes schlegeli) and red sea bream (Pagrus major) in the Northwest Pacific
Authors: Kang Donhyug , Hwang Doojin 
Published: June 2003

Abstract
This study determined the ex situ target strength (TS) of rockfish (Sebastes schlegeli) and red sea bream (Pagrus major) in an artificial seawater tank as a means of helping to estimate fishery resources in coastal areas. TS experiments were conducted at frequencies of 38 kHz (split beam), 120 kHz (split beam), and 200 kHz (dual beam). The species were examined under two conditions: first, live fish confined to a small, net cage; and, second, as free-swimming fish inside a large tank. The study examined 21 rockfish and 20 red sea bream. The data were used to obtain expressions for TS against length and weight for the two species. The relationships between TS and fish length were as follows: for rockfish, TS38 kHz = 20 log10(L) − 67.7 (r = 0.80), TS120 kHz = 20 log10(L) − 74.3 (r = 0.61), TS200 kHz = 20 log10(L) − 72.8 (r = 0.41); and for red sea bream, TS38 kHz = 20 log10(L) − 66.8 (r = 0.86), TS120 kHz = 20 log10(L) − 74.0 (r = 0.65), TS200 kHz = 20 log10(L) − 74.1 (r = 0.83). The TS equations for rockfish and red sea bream as a function of fish weight at 38 kHz were TS38 kHz = 6.75 log10(W) − 56.0 (r = 0.78) and TS38 kHz = 4.08 log10(W) − 49.9 (r = 0.89), respectively. For comparison, calculations using the Helmholtz–Kirchhoff ray-approximation model based on swimbladder morphology were compared with the measured TS. When the tilt angle of the fish is zero, the mean TS from the model is 3–10 dB higher than the experimental results, although the maximum TS values were only 3–4 dB different.
Mixture models for the species apportionment of hydroacoustic data, with echo-envelope length as the discriminatory variable
Authors: Fleischman Steve J , Burwen Debby L 
Published: June 2003

Abstract
For this side-looking, 200 kHz, split-beam sonar application, echo-envelope length has been shown to be predictive of fish size. In this study, this relationship is exploited to estimate the abundance of (large) chinook salmon (Oncorhynchus tshawytscha) in the presence of (smaller) sockeye salmon (Oncorhynchus nerka). The echo-length to fish-size relationship is too imprecise to ascertain the species of individual fish in the classic sense. However, the frequency distribution of echo-length measurements contains information on the relative abundance of chinook and sockeye salmon. The use of echo-length measurements in a mixture model is explored in order to estimate the proportion of total fish passage that comprised chinook salmon. Inputs to the model include empirical estimates of the length–frequency distribution for each species, parameter estimates from the regression relationship of echo-length to fish-length, and echo-length measurements from individual, ensonified fish. Outputs are estimates of the proportions of chinook and sockeye salmon in the river. The advantages of the mixture-model approach over threshold-based discrimination are discussed. Conditional maximum likelihood and Bayesian versions of the model are described. The method can be generalized to other hydroacoustic measurements, including target strength and other discrimination problems.
Acoustic observation and assessment of fish in high-relief habitats
Authors: Cooke K , Kieser R , Stanley R.D 
Published: June 2003

Abstract
Acoustics present an alternative sampling strategy in areas characterized by steep slopes and rugged terrain where fishing is impractical. However, when the interference between echoes from fish targets and boundaries is severe, acoustic observations require careful interpretation of the echo returns. This article outlines a method of generating a representative 3D model of the bottom topography that can assist in near-boundary fish discrimination. Images provide greater insight to echo source and highlight some of the difficulties associated with classifying acoustic sign. The results emphasize the importance of good survey design aimed at minimizing side-lobe interference and reducing acoustic-shadow zones.
Target strength of mesopelagic lanternfishes (family Myctophidae) based on swimbladder morphology
Authors: Yasuma Hiroki , Sawada Kouichi , Ohshima Tatsuki , Miyashita Kazushi , Aoki Ichiro 
Published: June 2003

Abstract
This article reports theoretical values of target strength (TS) for mesopelagic lanternfishes based on morphological measurements of their swimbladders. Three species of lanternfishes, Diaphus theta (26.9–77.4 mm standard length (SL)), Symbolophorus californiensis (85.0–108.4 mm SL), and Notoscopelus japonicus (126.0–133.2 mm SL), were examined. After external morphological measurement of the fish body, a specialized “soft X-ray” imaging system was used to map the swimbladders and obtain their morphological parameters. The swimbladder was inflated in D. theta, uninflated in S. californiensis, and was absent in N. japonicus. For D. theta, the swimbladder length does not increase in proportion to the body length, suggesting that the contribution of the swimbladder to acoustic reflection is reduced with growth in this fish. Based on the morphological measurements, the theoretical TS of the fish at 38 kHz was calculated using the approximate deformed-cylinder model (DCM) and the general prolate-spheroid model (PSM). For all three species, the calculations showed about 3 dB difference between the TS indicated by the DCM and PSM. Given that the description of body shape is poor in PSM, the DCM results were adopted for fish without a swimbladder or an empty one. The intercept b20 in the standard formula TS = 20 log SL + b20 was −85.7 dB (DCM) for S. californiensis and −86.7 dB (DCM) for N. japonicus. On the other hand, the PSM model was adopted for D. theta since its swimbladder has too small an aspect ratio to apply the DCM. For D. theta, the relationship between SL and TS is best expressed by TS = 11.8 log SL − 63.5, which implies that its scattering cross-section is not proportional to the square of the body length.
β‐Blocker treatment of patients with diastolic heart failure and arterial hypertension. A prospective, randomized, comparison of the long‐term effects of atenolol vs. nebivolol
Authors: Nodari Savina , Metra Marco , Dei Cas Livio 
Published: June 2003

AbstractWe compared the effects of 6 months administration of atenolol or nebivolol on resting and exercise hemodynamic parameters and maximal exercise capacity, in 26 patients with hypertension and left ventricular (LV) diastolic dysfunction (ejection fraction >50%, end‐diastolic diameter <60 mm and increased pulmonary wedge pressure at rest and/or at peak exercise). Both atenolol and nebivolol administration was associated with a significant decrease in the resting and peak exercise heart rate and blood pressure and in LV mass, with an increase in the E/A ratio. This latter effect was greater with nebivolol. Nebivolol was associated with an increase in the peak VO2, VO2 at the anaerobic threshold and with a decrease in the VE/VCO2 ratio. With regards to the hemodynamic parameters, compared to patients on atenolol, those on nebivolol showed a lower reduction in the cardiac index, a greater increase in the stroke volume index and a decline in the mean pulmonary artery pressure and pulmonary wedge pressure, both at rest and peak exercise. Thus, although the two β‐blockers have a similar antihypertensive action, nebivolol administration was associated with a greater hemodynamic improvement, compared to atenolol.
Characteristic substructures and properties in chemical
carcinogens studied by the cascade model
Authors: Okada Takashi 
Published: June 2003

Abstract
Motivation: Chemical carcinogenicity is an important subject in health and environmental sciences, and a reliable method is expected to identify characteristic factors for carcinogenicity. The predictive toxicology challenge (PTC) 2000–2001 has provided the opportunity for various data mining methods to evaluate their performance. The cascade model, a data mining method developed by the author, has the capability to mine for local correlations in data sets with a large number of attributes. The current paper explores the effectiveness of the method on the problem of chemical carcinogenicity.
Results: Rodent carcinogenicity of 417 compounds examined by the National Toxicology Program (NTP) was used as the training set. The analysis by the cascade model, for example, could obtain a rule ‘Highly flexible molecules are carcinogenic, if they have no hydrogen bond acceptors in halogenated alkanes and alkenes’. Resulting rules are applied to predict the activity of 185 compounds examined by the FDA. The ROC analysis performed by the PTC organizers has shown that the current method has excellent predictive power for the female rat data.
Availability: The binary program of DISCAS 2.1 and samples of input data sets on Windows PC are available at http://www.clab.kwansei.ac.jp/mining/discas/discas.html
Supplementary information: Summary of prediction results and cross validations is accessible via http://www.clab.kwansei.ac.jp/~okada/BIJ/BIJsupple.htm Used rules and the prediction results for each molecule are also provided.
Contact: okada-office@ksc.kwansei.ac.jp
A Bayesian network approach to operon prediction
Authors: Bockhorst Joseph , Craven Mark , Page David , Shavlik Jude , Glasner Jeremy 
Published: June 2003

Abstract
Motivation: In order to understand transcription regulation in a given prokaryotic genome, it is critical to identify operons, the fundamental units of transcription, in such species. While there are a growing number of organisms whose sequence and gene coordinates are known, by and large their operons are not known.
Results: We present a probabilistic approach to predicting operons using Bayesian networks. Our approach exploits diverse evidence sources such as sequence and expression data. We evaluate our approach on the Escherichia coli K-12 genome where our results indicate we are able to identify over 78% of its operons at a 10% false positive rate. Also, empirical evaluation using a reduced set of data sources suggests that our approach may have significant value for organisms that do not have as rich of evidence sources as E.coli.
Availability: Our E.coli K-12 operon predictions are available at http://www.biostat.wisc.edu/gene-regulation
Contact: joebock@biostat.wisc.edu
* To whom correspondence should be addressed.
Attendance at the accident and emergency department in the year before suicide: Retrospective study
Authors: Gairin Isaura , House Allan , Owens David 
Published: June 2003

BackgroundThe National Confidential Inquiry into suicides in England and Wales found that a quarter of suicides are preceded by mental health service contact in the year before death. However, visits to accident and emergency departments due to self-harm may not lead to a record of mental health service contact.AimsTo determine the proportion of suicides preceded by accident and emergency attendance in the previous year.MethodWe obtained the list of probable suicides in Leeds for a 38-month period, and examined the records from thecity's accident and emergency departments for a year before each death.ResultsEighty-five (39%) of the 219 people who later died by suicide had attended an accident and emergency department in the year before death, 15% because of non-fatal self-harm. Final visits dueto self-harm were often shortly before suicide (median 38 days), but the National Confidential Inquiry recorded about a fifth of them as‘not in contact’ with local mental health services.ConclusionsAlthough many suicides are preceded by recent attendance at accident and emergency departments due to non-fatal self-harm, local mental health service records may show no recent contact. Suicide prevention might be enhanced were accident and emergency departments and mental health services to work together more closely.