bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rotational vibration of poly(tetrafluoroethylene) chains by the electron spin resonance method
Authors: Hara Shigeo , Yamamoto Katsuhiro , Shimada Shigetaka , Nishi Hajime 
Published: March 2004

AbstractTemperature‐dependent electron spin resonance spectra of main‐chain free radicals, CF2(β)C · F(α)CF2(β), in poly(tetrafluoroethylene) (PTFE) were analyzed by the change in the hyperfine splitting due to β‐fluorines, which was a decreasing function of the observation temperature. The results were interpreted in terms of the rotational vibration around the CαCβ bond. The amplitude of the vibration was estimated on the assumption of its harmonic oscillation. The vibration of the PTFE chain was found to have a large amplitude in comparison with that of a polyethylene chain in single crystals. The vibration of the large amplitude was caused by a weak interchain interaction in the PTFE matrices. The amplitude of the vibration in crosslinked PTFE was much larger than that in noncrosslinked PTFE. This result indicated that the free radicals in crosslinked PTFE were trapped in the amorphous region, which had the disordered sites of crosslinking, whereas the free radicals in noncrosslinked PTFE were mainly trapped in the paracrystalline region. The decay reaction of the free radicals in the PTFE matrices was also related to the heterogeneity in the structure and the rotational vibration. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1539–1547, 2004
Polyelectrolyte complexes of linear copolymers and hydrogels based on 2‐[(methacryloyloxy)ethyl]trimethylammonium chloride and N‐isopropylacrylamide
Authors: Mun Grigoriy A. , Khutoryanskiy Vitaliy V. , Nurkeeva Zauresh S. , Sergaziyev Aibek D. , Fefelova Natalia A. , Rosiak Janusz M. 
Published: March 2004

AbstractThe formation of polyelectrolyte complexes of linear copolymers and hydrogels based on copolymers of 2‐[(methacryloyloxy)ethyl]trimethylammonium chloride with N‐isopropylacrylamide (MADQUAT–NIPAAM) and poly(acrylic acid) (PAA) has been studied. The composition of the copolymer has been found to affect the composition of the polyelectrolyte complexes significantly, and the molecular weight of PAA influences their aggregation stability. Hydrogels of MADQUAT–NIPAAM immersed in solutions of PAA undergo contraction because of the formation of gel–polymer complexes. The rate of contraction and the final swelling degree of the gel–polymer complexes depend on the concentration of PAA in solution and its molecular weight. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1506–1513, 2004
Representations of the Schrödinger algebra and Appell systems
Authors: Feinsilver P. , Kocik J. , Schott R. 
Published: March 2004

AbstractWe investigate the structure of the Schrödinger algebra. Two constructions are given that yield the physical realization via general methods starting from the abstract Lie algebra. Representations are found on a Fock space with basis given by a canonical Appell system. Generalized coherent states are used in the construction of the Hilbert space of functions on which certain commuting elements act as self‐adjoint operators. This yields a probabilistic interpretation of these operators as random variables. An interesting feature is how the semidirect product structure of the Lie algebra is reflected in the probability density function. A Leibniz function and orthogonal basis for the Hilbert space are found. Then certain evolution equations connected with canonical Appell systems on this algebra are shown.
Note on the holographic c‐function
Authors: Miemiec A. 
Published: March 2004

AbstractWe discuss the holographic c‐function and describe an algorithm for the practical computation of the changing central charge in arbitrary RG‐flows. The conclusions are drawn from studying a particular example, which is worked out in detail. The renormalisation procedure of hep‐th/0112150 necessary to obtain the central charge is reviewed.
Quantization of the optical phase space 𝒮2 = {ϕ mod 2π, I > 0} in terms of the group SO↑(1, 2)
Authors: Kastrup H.A. 
Published: March 2004

AbstractFor a considerably expanded Chap. 4 (Harm. osc.) and additional references see e‐print archives quant‐ph/0307069.
A simple criterion for successful biological control on annual crops
Authors: Urano Satoru , Shima Katsuya , Hongo Koichi , Suzuki Yoshito 
Published: March 2004

AbstractPopulation dynamics of pest insect‐natural enemy systems on annual crops is quite different from those seen in classic biological control programes. On an annual crop, for example, the persistence of populations of pest insects is forced to terminate when crops are harvested. Pest control on annual crops aims to suppress the maximum density of the pest below a certain level, and a low level equilibrium is not always the aim. It is important to determine the initial impact just after release of a natural enemy in order to determine the success of a biological control program. Therefore, effectiveness of natural enemies should be evaluated by prediction of such short‐term population dynamics. This paper presents a new and simple analytical model for successful biological control on annual crops. A criterion of successful biological control is given as the ratio of the pest and natural enemy populations just when the pest begins to decrease. This ratio is derived from the intrinsic rates of natural increase of both populations and the daily total predation by natural enemies. Using this model, criteria on appropriate number and time of release of natural enemies are obtained. The practical applications of this model are discussed with respect to evaluating the success or failure of natural enemy releases in future biological control programs.
Dispersal patterns of endemic alpine butterflies with contrasting population structures:Erebia epiphronandE. sudetica
Authors: Kuras Tomas , Benes Jiri , Fric Zdenek , Konvicka Martin 
Published: March 2004

AbstractWe studied population sizes and mobility ofErebia epiphronandErebia sudetica, two high mountain butterflies forming endemic subspecies in the Hrubý Jeseník Mountains, Czech Republic.E. epiphronformed two continuous populations containing ≈100,000 and ≈4,500 individuals on alpine grasslands. The butterflies moved freely within their habitats, but movements between the two populations were highly unlikely.E. sudeticaformed a system of colonies at timberline sites on valley headwalls and in forest clearings. Two such colonies studied in detail contained ≈4,500 and ≈450 adults and were interconnected by limited dispersal. The negative exponential function and the sigmoid function (this assumes flat decrease of movements over short distances) were superior to the inverse power function in fitting mobility data for both species. ForE. sudetica, the functions describing movements within a habitat differed significantly from total movements, suggesting different behaviours of dispersing individuals. The habitats ofE. epiphronare uniform and highly isolated, favouring free within‐habitat mobility but prohibiting leaving their boundaries. The habitats ofE. sudeticaare diverse and disturbance‐dependent; leaving such habitats is less risky, and a source‐sink model may explain the persistence of the species in the mountains.
Estimation of dispersal distance by mark‐recapture experiments using traps: correction of bias caused by the artificial removal by traps
Authors: Yamamura Kohji , Kishita Mitsunobu , Arakaki Norio , Kawamura Futoshi , Sadoyama Yasutsune 
Published: March 2004

AbstractAlthough in mark‐recapture experiments traps are useful to estimate the dispersal distance of organisms, they cause a dilemma that may be called a kind of Heisenberg effect: a large number of traps should be placed to yield a precise estimate of mean dispersal distance, while these traps shorten the mean dispersal distance itself by intercepting organisms that should have dispersed for further distances. We propose a procedure to solve this dilemma by placing traps uniformly in a lattice pattern, and by assuming a random movement and a constant rate of settlement for organisms. We applied this procedure to estimate the dispersal distance of the sugarcane wirewormMelanotus okinawensisOhira (Coleoptera: Elateridae). The estimated mean dispersal distance was 143.8 m. Through the use of a conventional method of estimation, the mean dispersal distance was estimated to be 118.1 m. Thus, it was shown that the conventional estimate of dispersal distance was 18% smaller than the corrected estimate in our experiment.
Radiation and reticulation: extensive introgressive hybridization in the carabid beetles Ohomopterus inferred from mitochondrial gene genealogy
Authors: Sota T. 
Published: March 2004

AbstractIn the evolutionary process of an animal lineage, interactions in secondary contacts of differentiated populations and introgressive hybridization may play an important role. In the Japanese islands, the carabid subgenus Ohomopterus (genus Carabus) exhibits a marked differentiation in body size and genital morphology. Although geographical differentiation is apparent, two or three species usually coexist at many localities. Their reproductive isolation relies on body size differences, chemical cues for mate recognition, and a species‐specific genital lock‐and‐key system. However, these isolation mechanisms are not always effective enough to prevent interspecific hybridization. An initial assessment of the species‐level phylogeny with mitochondrial gene sequences revealed that the gene genealogy is highly inconsistent with the morphology‐based taxonomy. A comparison of mitochondrial and nuclear gene genealogies showed that these are strongly incongruent with each other, while the nuclear gene genealogy is more consistent with traditional taxonomy, indicating the repeated occurrence of introgression of mitochondria across species. Here, two different cases of mitochondrial introgression among Ohomopterus species are described in detail, one for parapatric species and the other for sympatric species. First, mitochondrial haplotypes and sequences were studied in Carabus insulicola and three taxa parapatric with C. insulicola, at least two of which hybridize with C. insulicola naturally. Among the four species studied, directional introgressions of mitochondria across boundary zones were detected. Second, in the Mt. Kongo area in central Honshu, which harbors five species, introgression of mitochondria among four out of the five species was detected, despite the apparent absence of on‐going natural hybridization. These inferred cases of mitochondrial introgression indicate that species interactions through hybridization could have played an important role at various stages in the evolution of Ohomopterus.
Modeling species richness controlled by community‐intrinsic and community‐extrinsic processes: coastal fish communities as an example
Authors: Stenseth N. C. , Lekve K. , Gjøsæter J. 
Published: March 2004

AbstractThis article focuses on the analysis of coastal fish communities along the Norwegian Skagerrak coast. Species numbers are estimated based on annual samples of the fish communities within 12 fjords from 1953 to 1994. On this basis, a community dynamics model (incorporating both community‐intrinsic and community‐extrinsic processes) was developed and analyzed. This model is then discussed on the basis of other community models available through the literature, both phenomenologically oriented and process‐oriented models.
Indeterminate growth is selected by a trade‐off between high fecundity and risk avoidance in stochastic environments
Authors: Katsukawa Y. , Katsukawa T. , Matsuda H. 
Published: March 2004

AbstractWe developed a stage‐structured model to describe optimal energy allocation among growth, reproduction, and survival. Our model includes stochastic fluctuations in survival rate at age 0 but constant survival rate at older ages. Many mammals and birds cease to grow after maturity (i.e., determinate growth), whereas organisms in a number of other taxa grow beyond maturation (i.e., indeterminate growth). We discuss the conditions under which each of the following strategies is optimal: (I) semelparity, (II) iteroparity with determinate growth, and (III) iteroparity with indeterminate growth. Our model demonstrates that iteroparity with indeterminate growth is selected for when a nonlinear relationship exists between weight and energy production; this strategy is also often selected for in stochastic environments, even with a linear relationship between weight and energy production. The optimal strategy in stochastic environments is to maximize the long‐term population growth rate, which does not correspond with maximization of total fecundity. The optimal life history is determined by a balance between spreading a risk and increasing the number of offspring. Our model suggests that optimal life history strategy depends on the magnitude of environmental fluctuations, the advantage of investing in growth, the cost of survival, and the nonlinearity between weight and energy production.
Evolution of apomixis as a strategy of colonization in the dioecious species Lindera glauca (Lauraceae)
Authors: Dupont Y. L. 
Published: March 2004

AbstractI have investigated the reproductive biology of four dioecious species of Lindera in Japan: Lindera obtusiloba Bl., L. umbellata Thunb., L. erythrocarpa Makino, and L. glauca Bl. The sex ratios in populations of the first three species are close to equality, but in L. glauca only female individuals are found in Japan, although males are known from continental Asia. The persistence of this dioecious species in the absence of males is surprising, and prompts the question: What mechanisms operate to ameliorate problems of colonization in species of Lindera? I carried out bagging experiments in order to test for apomixis (asexual reproduction by seeds) and to establish the importance of pollination and fertilization, and potential pollen vectors. Only L. glauca reproduced by apomixis. Level of fruit set was high, and was not affected by pollination. In the other three species, seed set was entirely dependent on pollen transfer, which could be accomplished by small Coleoptera and Diptera. The evolution of apomixis in L. glauca appears to have been a strategy to overcome sterility and establish a population in the Japanese islands even in the absence of males. However, this change in breeding system has not occurred in congeneric, co‐occurring species, which do not seem to have experienced a lack of male plants.
Differentiation of chromaffin cells elicited by ELF MF modifies gene expression pattern
Authors: Olivares‐Bañuelos Tatiana , Navarro Luz , González Alicia , Drucker‐Colın Rene 
Published: March 2004

AbstractChromaffin cells exposed to extremely low frequency magnetic fields (ELF MF, 60 Hz, 0.7 mT) differentiate into sympathetic neuron‐like cells. This complex process must involve both qualitative and quantitative variations in gene expression. This study looks at whether ELF MF treatment provokes changes in the global transcription profile of chromaffin cells, using the RT‐Differential Display method. When the gene expression patterns of experimental groups (nerve growth factor (NGF) and ELF MF) were compared to those receiving no treatment, at least 53 transcripts showing differential expression were detected. Eight RT—PCR products, corresponding to six genes, were re‐amplified, sequenced and compared with the rat gene bank. Sequence analysis showed that these genes most likely encode: phosphoglucomutase‐1, neurofibromatosis‐2 interacting protein, microtubule associated protein‐2, thiamine pyrophosphokinase, and two unidentified hypothetical proteins (RNOR02022103 and ROR01044577), and that the presumed regulatory regions of these genes contained CTCT‐clusters, which are thought to be required for electromagnetic field‐dependent gene expression.
Efficacy of coeliac plexus and splanchnic nerve blockades in body and tail located pancreatic cancer pain
Authors: Özyalçın N. Süleyman , Talu Gül Köknel , Çamlıca Hakan , Erdine Serdar 
Published: March 2004

AbstractPalliative treatment, pain therapy and quality of life (QOL) are very important in pancreatic cancer patients. We evaluated the pain relieving efficacy, side effects and effects on QOL of neurolytic coeliac plexus blockade (NCPB) and splanchnic nerves neurolytic blockade (SNB) in body and tail located pancreatic cancer.The study protocol was approved by the local ethics committee. Patients were randomly divided into two groups. Coeliac group; GC, N=19 were treated with coeliac plexus blockade, whereas the patients in splanchnic group; GS, N=20 were treated with bilateral splanchnic nerve blockade. The VAS values, opioid consumption and QOL (Patient satisfaction scale=PSS, performance status scale=PS) were evaluated prior to the procedure and at 2 weeks intervals after the procedure with the survival rates.The demographic features were found to be similar. The VAS differences (difference of every control's value with baseline value) in GS were significantly higher than the VAS differences in GC on every control meaning that VAS values in GS decreased more than the VAS values in GC. GS patients were found to decrease the opioid consumption significantly more than GC till the 6th control. GS patients had significant improvement in PS values at the first control. The mean survival rate was found to be significantly lower in GC. Two patients had severe pain during injection in GC and 5 patients had intractable diarrhoea in GC.Comparing the ease, pain relieving efficacy, QOL‐effects of the methods, splanchnic nerve blocks may be an alternative to coeliac plexus blockade in patients with advanced body and tail located pancreatic cancer.
Sex differences in pain and analgesia: the role of gonadal hormones
Authors: Craft Rebecca M. , Mogil Jeffrey S. , Aloisi Anna Maria 
Published: March 2004

AbstractThere is now strong evidence for sex differences in pain and analgesia. These differences imply that gonadal steroid hormones such as estradiol and testosterone modulate sensitivity to pain and analgesia. The goal of this review is to present an overview of gonadal steroid modulation of pain and analgesia in animals and humans, and to describe mechanisms by which males' and females' biology may differentially predispose them to pain and to analgesic effects of drugs and stress. Evidence is presented to demonstrate that sex differences in pain and analgesia may be both quantitative and qualitative in nature. Current research suggests that sex‐specific management of clinical pain will be a reality in the not‐so‐distant future.
Sex‐based differences in gastrointestinal pain
Authors: Mayer Emeran A. , Berman Steve , Chang Lin , Naliboff Bruce D. 
Published: March 2004

AbstractRecent interest has focused on sex‐related differences in irritable bowel syndrome (IBS) physiology and treatment responsiveness to novel pharmacologic therapies. Similar to a variety of other chronic pain conditions and certain affective disorders, IBS is more prevalent amongst women, both in population‐based studies as well as in clinic‐based surveys. Non‐painful gastrointestinal symptoms, constipation and somatic discomfort are more commonly reported by female IBS patients. While perceptual differences to rectosigmoid stimulation are only observed following repeated noxious stimulation of the gut, sex‐related differences in certain sympathetic nervous system (SNS) responses to rectosigmoid stimulation are consistently seen. Consistent with experimental findings in animals, current evidence is consistent with a pathophysiological model which emphasizes sex‐related differences in autonomic and antinociceptive responses to certain visceral stimuli.
The role of the pain‐evoked negative difference potential in dual‐task response conflict
Authors: Dowman Robert 
Published: March 2004

AbstractThe possible role of the generators of the sural nerve pain‐evoked negative difference potential (NDP), the anterior cingulate cortex and supplementary somatosensory area, in monitoring response conflict was investigated in 19 healthy adults. Each trial consisted of a visual arrow stimulus and a painful electrical stimulus applied to the sural nerve. The subjects determined whether their left or right sural nerve had been stimulated and whether the arrow was pointing to the left or to the right. The sural nerve pain detection task reaction times and response errors were greater in the incongruent condition, where the arrow pointed to the side opposite of that receiving the sural nerve pain, than in the congruent condition, where the arrow pointed to the same side as that receiving the sural nerve pain. Response conflict was greatest, therefore, in the incongruent condition. There were no differences in NDP amplitude across the congruent and incongruent conditions. These results argue against the hypothesis that the NDP generators are involved in monitoring response conflict.
Prevalence and characteristics of chronic pain in the general Norwegian population
Authors: Rustøen Tone , Wahl Astrid Klopstad , Hanestad Berit Rokne , Lerdal Anners , Paul Steven , Miaskowski Christine 
Published: March 2004

AbstractBackground. Population‐based studies suggest that prevalence of chronic pain is increasing. The purpose of this study was to determine the prevalence of chronic pain in a sample drawn from the general Norwegian population. In addition, the characteristics of chronic pain, as well as differences in demographic characteristics and health‐related variables between persons with and without chronic pain were evaluated.Methods. A total of 4000 Norwegian citizens, were randomly drawn from the National Register, by Statistics Norway and were mailed a questionnaire.Results. The response rate was 48.5%. The majority of the sample was female (51%), married (59%), and working for pay (69%) with a mean age of 45.2 years. The prevalence of chronic pain in the total sample was 24.4%, and 65% of the participants with chronic pain indicated that they had experienced chronic pain for over 5 years. The cause of the pain was not specified by 57% of the participants in chronic pain, and 31% reported no pain treatments. Women, older individuals, persons with less education, and those who were pensioned, reported chronic pain more frequently. The results of a logistic regression analysis indicate that the variables that provide unique contributions to predicting pain group memberships were: gender, education, being frequently ill, or having a chronic illness.Conclusions. These findings suggest that chronic pain is a significant problem in the general Norwegian population, and that gender, education, being frequently ill, or having a chronic illness are important variables in predicting pain group membership.