bluuebunny/crossref_metadata_2025 huggingface dataset:
Struggling for hopefulness: a qualitative study of Swedish women who self‐harm
Authors: LINDGREN B.‐M. , WILSTRAND C. , GILJE F. , OLOFSSON B.
Published: May 2004

There has been an increase in the number of Swedish psychiatric patients who self‐harm, yet self‐harm is seldom described in published research. The aim of this study was to describe how people who self‐harm experience received care and their desired care. Nine participants, all Swedish women who had been treated for inpatient or outpatient psychiatric care, narrated their experiences of care for self‐harm. Using qualitative content analysis, two themes were formulated: ‘Expecting to be confirmed while being confirmed fosters hopefulness’; and, ‘Expecting to be confirmed while not being confirmed stifles hopefulness’. Each of these themes emerged from five subthemes that clustered around positive and negative aspects of being seen–not being seen, being valued–being stigmatized, being connected–disconnected, being believed–doubted, and being understood–not being understood. Of significance is for nurses to view persons who self‐harm as human beings and to grasp the importance of being confirmed by staff that can foster hopefulness in persons who self‐harm, yet realize the possibility of the paradoxical nature of hopefulness and being confirmed.
Putting it all together: dealing with complexity in the understanding of the human condition
Authors: GALLOP R. , REYNOLDS W.
Published: May 2004

In this paper, two mental health nurses who have experienced long academic careers reflect on the way their own thinking and teaching about the human condition has changed over the course of their careers. Three major paradigms that have attempted to explain the human condition, the biological sciences, psychodynamic theory, and socio‐cultural theory, are discussed. It is argued that no single approach is sufficient to address the complexities of providing care within psychiatric and mental health nursing. It is further argued that the integration of these perspectives has not been well considered or articulated in practice. The authors conclude that the arguments presented in this paper are likely to challenge people's loyalties to a particular perspective of the human condition.
Water ascent in tall trees: does evolution of land plants rely on a highly metastable state?
Authors: Zimmermann Ulrich , Schneider Heike , Wegner Lars H. , Haase Axel
Published: May 2004

The Cohesion Theory considers plant xylem as a ‘vulnerable pipeline’ isolated from the osmotically connected tissue cells, phloem and mycorrhizas living in symbiosis with plant roots. It is believed that water is pulled exclusively by transpiration‐induced negative pressure gradients of several megapascals through continuous water columns from the roots to the foliage. Water under such negative pressures is extremely unstable, particularly given the hydrophobicity of the inner xylem walls and sap composition (lipids, proteins, mucopolysaccharides, etc.) that prevents the development of stable negative pressures larger than about −1 MPa. However, many plant physiologists still view the Cohesion Theory as the absolute and universal truth because clever wording from the proponents of this theory has concealed the recent breakdown of the Scholander pressure bomb (and other indirect methods) as qualified tools for measuring negative pressures in transpiring plants. Here we show that the arguments of the proponents of the Cohesion Theory are completely misleading. We further present an enormous bulk of evidence supporting the view that – depending on the species and ecophysiological context – many other forces, additional to low tensions, can be involved in water ascent and that water can be lifted by a series of watergates (like ships in staircase locks).

ContentsI.Introduction576II.Can water sustain negative pressures?577III.Negative xylem pressures of several megapascals: fact or mystery?579IV.The continuity of the xylem water columns: fact or hypothesis?588V.The ‘Multi‐Force’ or ‘Watergate’ Theory590VI.Conclusions604Acknowledgements605References605Appendix 1612Appendix 2613
Inferring nocturnal surface fluxes from vertical profiles of scalars in an Amazon pasture
Authors: Acevedo Otávio C. , Moraes Osvaldo L. L. , Da Silva Rodrigo , Fitzjarrald David R. , Sakai Ricardo K. , Staebler Ralf M. , Czikowsky Matthew J.
Published: May 2004

Ecosystem carbon budgets depend on there being good representative surface flux observations for all land use types during the entire diurnal cycle. In calm conditions that often occur at night, especially in areas of small roughness (such as pastures), ecosystem respiration rate is poorly measured using the eddy covariance (EC) technique. Nocturnal vertical profiles of temperature, humidity and winds were observed using tethered balloon soundings in a pasture in the eastern Amazon during two campaigns in 2001. The site is characterized by very weak winds at night, so that there is insufficient turbulence for the EC technique to determine fluxes accurately. To compensate, the time evolution of the profiles is used to determine surface fluxes at early morning and these are compared with those observed by EC at a nearby micrometeorological tower. The nocturnal boundary layer thickness h is determined as the height to which the surface fluxes must converge so that energy budget closure is achieved. The estimated values range from 30 m, around 22:00 hours LST, to more than 100 m just before dawn. These are in good agreement with the observed thickness of a frequently observed fog layer during the middle of the night. During the early portion of the night, when the accumulation layer is shallow, there is appreciable decrease of dCO2/dt with height. On calm nights, CO2 accumulation rate is larger near the surface than at higher levels. On windier nights, this accumulation rate is vertically uniform. Hence, extrapolation of tower profiles for estimating fluxes must be done carefully. Although uncertainties remain large, an alternate approach to the EC method is described for measuring nighttime surface CO2 fluxes under stable atmospheric conditions.
Variation in potential for isoprene emissions among Neotropical forest sites
Authors: Harley Peter , Vasconcellos Pérola , Vierling Lee , Pinheiro Carlos Cleomir de S. , Greenberg James , Guenther Alex , Klinger Lee , Almeida Samuel Soares de , Neill David , Baker Tim , Phillips Oliver , Malhi Yadvinder
Published: May 2004

As part of the Large Scale Biosphere–Atmosphere Experiment in Amazônia (LBA), we have developed a bottom‐up approach for estimating canopy‐scale fluxes of isoprene. Estimating isoprene fluxes for a given forest ecosystem requires knowledge of foliar biomass, segregated by species, and the isoprene emission characteristics of the individual tree species comprising the forest. In this study, approximately 38% of 125 tree species examined at six sites in the Brazilian Amazon emitted isoprene. Given logistical difficulties and extremely high species diversity, it was possible to screen only a small percentage of tree species, and we propose a protocol for estimating the emission capacity of unmeasured taxa using a taxonomic approach, in which we assign to an unmeasured genus a value based on the percentage of genera within its plant family which have been shown to emit isoprene.

Combining this information with data obtained from 14 tree censuses at four Neotropical forest sites, we have estimated the percentage of isoprene‐emitting biomass at each site. The relative contribution of each genus of tree is estimated as the basal area of all trees of that genus divided by the total basal area of the plot. Using this technique, the percentage of isoprene‐emitting biomass varied from 20% to 42% (mean=31%; SD=8%).

Responses of isoprene emission to varying light and temperature, measured on a sun‐adapted leaf of mango (Mangifera indica L.), suggest that existing algorithms developed for temperate species are adequate for tropical species as well. Incorporating these algorithms, estimates of isoprene‐emitting biomass, isoprene emission capacity, and site foliar biomass into a canopy flux model, canopy‐scale fluxes of isoprene were predicted and compared with the above‐canopy fluxes measured at two sites. Our bottom‐up approach overestimates fluxes by about 50%, but variations in measured fluxes between the two sites are largely explained by observed variation in the amount of isoprene‐emitting biomass.
Soil CO2 efflux in a tropical forest in the central Amazon
Authors: Doff sotta Eleneide , Meir Patrick , Malhi Yadvinder , Donato nobre Antonio , Hodnett Martin , Grace John
Published: May 2004

This study investigated the spatial and temporal variation in soil carbon dioxide (CO2) efflux and its relationship with soil temperature, soil moisture and rainfall in a forest near Manaus, Amazonas, Brazil. The mean rate of efflux was 6.45±0.25 SE μmol CO2 m−2s−1 at 25.6±0.22 SE°C (5 cm depth) ranging from 4.35 to 9.76 μmol CO2 m−2s−1; diel changes in efflux were correlated with soil temperature (r2=0.60). However, the efflux response to the diel cycle in temperature was not always a clear exponential function. During period of low soil water content, temperature in deeper layers had a better relationship with CO2 efflux than with the temperature nearer the soil surface. Soil water content may limit CO2 production during the drying‐down period that appeared to be an important factor controlling the efflux rate (r2=0.39). On the other hand, during the rewetting period microbial activity may be the main controlling factor, which may quickly induce very high rates of efflux. The CO2 flux chamber was adapted to mimic the effects of rainfall on soil CO2 efflux and the results showed that efflux rates reduced 30% immediately after a rainfall event. Measurements of the CO2 concentration gradient in the soil profile showed a buildup in the concentration of CO2 after rain on the top soil. This higher CO2 concentration developed shortly after rainfall when the soil pores in the upper layers were filled with water, which created a barrier for gas exchange between the soil and the atmosphere.
Coarse woody debris in undisturbed and logged forests in the eastern Brazilian Amazon
Authors: Keller Michael , Palace Michael , Asner Gregory P. , Pereira Rodrigo , Silva José Natalino M.
Published: May 2004

Coarse woody debris (CWD) is an important component of the carbon cycle in tropical forests. We measured the volume and density of fallen CWD at two sites, Cauaxi and Tapajós in the Eastern Amazon. At both sites we studied undisturbed forests (UFs) and logged forests 1 year after harvest. Conventional logging (CL) and reduced impact logging (RIL) were used for management on areas where the geometric volumes of logs harvested was about 25–30 m3 ha−1. Density for five classes of fallen CWD for large material (>10 cm diameter) ranged from 0.71 to 0.28 Mg m−3 depending upon the degree of decomposition. Density of wood within large fallen logs varied with position relative to the ground and with distance from the center of the log. Densities for materials with diameters from 2 to 5 and 5 to 10 cm were 0.36 and 0.45 Mg m−3, respectively. The average mass (±SE) of fallen CWD at Cauaxi was 55.2 (4.7), 74.7 (0.6), and 107.8 (10.5) Mg ha−1 for duplicate UF, RIL, and CL sites, respectively. At Tapajós, the average mass of fallen CWD was 50.7 (1.1) Mg ha−1 for UF and 76.2 (10.2) Mg ha−1 for RIL for duplicate sites compared with 282 Mg ha−1 for live aboveground biomass. Small‐ and medium‐sized material (<10 cm dia.) accounted for 8–18% of the total fallen CWD mass. The large amount of fallen CWD at these UF sites relative to standing aboveground biomass suggests either that the forests have recently been subjected to a pulse of high mortality or that they normally suffer a high mortality rate in the range of 0.03 per year. Accounting for background CWD in UF, CL management produced 2.7 times as much CWD as RIL management. Excess CWD at logging sites would generate a substantial CO2 emission given the high rates of decay in moist tropical forests.
Land‐use change effects on local energy, water, and carbon balances in an Amazonian agricultural field
Authors: Sakai Ricardo K. , Fitzjarrald David R. , Moraes Osvaldo L.L. , Staebler Ralf M. , Acevedo Otávio C. , Czikowsky Matthew J. , Silva Rodrigo da , Brait Eleazar , Miranda Valdelirio
Published: May 2004

To study how changing agricultural practices in the eastern Amazon affect carbon, heat and water exchanges, a 20 m tower was installed in a field in August 2000. Measurements include turbulent fluxes (momentum, heat, water vapor, and CO2) using the eddy covariance (EC) approach, soil heat flux, wind, and scalar profiles (T, q, and CO2), soil moisture content, terrestrial, total solar radiation, and photosynthetically active radiation (PAR, 400–700 nm). At the beginning of the measurements, in September 2000, the field was a pasture. On November 2001, the pasture was burned, plowed, and planted in upland (nonirrigated) rice.

Calm nights were the norm in this site. Anomalously low values of net ecosystem exchange (NEE) were found using the EC method, even when the common criterion u*<0.2 m s−1 was used to identify and exclude poor performance nights. We observed more plausible values of NEE using criterion u*<0.08 m s−1, indicating that the criterion must be revised downward for flow over surfaces smoother than forests. However, even using the lower threshold, u* was lower than this limit for 82% of nights, and this led to nocturnal respiration underestimates. We compensate for this difficulty by estimating the respiration rate using the nocturnal boundary layer budget method.

Land‐use change from pasture to rice cultivation strongly affected both diurnal rates of turbulent exchange but also the pattern of seasonal variation. Seasonal wet and dry season differences in vegetation state were clearly detected in the albedo and PAR‐albedo. These reflectivity changes were accompanied by modified net radiative flux, turbulent heat flux and evaporation rates. The highest evaporation rate was observed during the rice crop, when the field had total evaporation approximately half the precipitation input, less than that of the surrounding forest. Effects of the land‐cover changes were also detected in the carbon budget. For the pasture, the maximum CO2 uptake occurred in May, appreciably delayed from the start of the rainy season. After the field was plowed and the soil was exposed and there was efflux of CO2 to the atmosphere day and night for an extended period. Highest values of carbon uptake occurred during the rice plantation. Although the upland rice took up carbon at double the rate of the pasture that it replaced, the field was left fallow for much of the year, during the dry season.
Combined technique with polyethylene fibers and composite resins in restoration of traumatized anterior teeth
Authors: Vitale Marina Consuelo , Caprioglio Claudia , Martignone Alessandra , Marchesi Umberto , Botticelli A. R.
Published: May 2004

Abstract  – Traumatized anterior teeth need quick esthetic and functional repair. Esthetic requirements of anterior teeth require the use of composite materials which, in the most complex cases, can be used in association with fibers so as to improve their mechanical resistance. Many kinds of fibers are available. The authors considered parameters such as physical properties, water absorption, ease of cutting and of laying. Polyethylene fibers appear to have the best properties in elasticity, translucency, adaptability, tenaciousness, resistance to traction and to impact. Fifteen children, between 7 and 13 years old, with crown fractures of the anterior sector were treated. In the case of a simple crown fracture, the missing part was restored by polyethylene fibers and composite resins. In the case of a complex crown fracture needing endodontic treatment, the fibers were used as a central core stump in order to restore the dental morphology. At control examinations, the teeth restored by this technique were acceptable, both in function and in aesthetics. Thus, the authors recommend this combined technique for predictable restoration of traumatized anterior teeth.
Type of treatment, prognosis, and estimation of time spent to manage dental trauma in late presentation cases at a dental teaching hospital: a longitudinal and retrospective study
Authors: Al‐Jundi Suhad H.
Published: May 2004

Abstract –  Traumatic dental injuries are emergencies that must be treated promptly and properly in order to reduce the suffering, costs, and time for patients, parents, and health care providers. The aim of this study was to investigate the treatment, long‐term prognosis, and number of visits needed to manage cases resulting from complications of late presentation of traumatic dental injuries. The sample consisted of 195 children, all presented with complications of dental trauma at the Pediatric Dentistry Clinics in the Dental Teaching Hospital of Jordan University of Science and Technology in Irbid city, Jordan. Retrospective data relied on trauma forms as well the clinical notes and radiographs in the patients' records. Prospective data was collected by examining patients at recall appointments. The treatment of traumatized teeth in this sample ranged from no active treatment to extraction and prosthetic replacement. It was estimated that the number of visits needed to carry out the planned treatment for these patients ranged between 3 and 17.2 visits according to the type of treatment. Apexification procedure was the most time consuming. Thirty‐two per cent of teeth with apexification ended up with root fracture mainly subsequent to another minor trauma episode (in 85%), the rest were reported to be spontaneous fractures. Almost half of the teeth with luxation injuries became necrotic after 3 years. Teeth with avulsion actually kept on deteriorating even at the 36‐month follow‐up appointment. The long‐term prognosis of teeth with middle root fracture was favorable in (80%) of the teeth in the sample, despite the fact that they were splinted late. Luxation injuries led to more necrotic teeth (50%) than uncomplicated crown fractures. Multiple dental trauma episodes (MDTE) were reported in about 30% of the patients in the sample and were responsible for some of the complications noticed in this report. As all cases followed up in this report are late presentation of dental trauma, the findings may emphasize and highlight predictors for healing and favorable long‐term prognosis for such injuries. This will help selecting the treatment option that would lead to better outcomes with less expense and less time consumption for dentists and patients alike. The findings of this report also stress the importance of prevention of dental trauma and minimize its complications through proper treatment, educational programs, supervision of children during play, use of mouth guards, and orthodontic treatment of proclined incisors.
Socio‐economic burden of permanent incisor replantation on children and parents
Authors: Nguyen Phu‐My T. , Kenny David J. , Barrett Edward J.
Published: May 2004

Abstract –  This study describes the socio‐economic burden and attitudes of children and their parents following replantation of avulsed incisors. Records of 80 patients with 99 avulsion injuries treated in a teaching hospital clinic from 1988 to 1999 were reviewed. Mean age at time of injury was 10.6 years (range = 6.6–17.7 years). Complete records for a minimum of 1 year were obtained for 43 patients with 60 replanted incisors. Mean treatment procedures provided during the first year included 5.5 diagnostic periapical radiographs, 1.9 occlusal radiographs, 1.3 pulpectomies, and 2.7 pulp medicament applications. The mean estimated treatment cost and direct time (dentist) for first‐year post‐trauma management was $1465 CAD and 7.2 h, respectively. Treatment costs were significantly higher during the first year post‐trauma for patients who had their incisors extracted (P = 0.04), but there was no significant difference in direct treatment time between the two groups (P = 0.19). Twenty‐one patient–parent pairs were surveyed for a number of qualitative factors. Ninety per cent of patients and 86% of parents reported that school and work time was lost. Even after having gone through the painful experience of replantation, the demands of recall, and in some cases, extraction, the majority of patients (67%) and parents (81%) stated that they would have still made the same (replantation) decision. Patient and parent responses were not statistically different (P = 0.453). Almost half the parents stated they would be willing to pay over $2000 CAD to save an incisor. Patients rated retention of an incisor as significantly more important than infraocclusion. This is the first study to quantify the treatment burden of replantation of avulsion injuries exclusively in the pediatric population. This study describes the socio‐economic burden and responsibilities of patient/parent and dentist and their role in informed consent.
Dental injury among Brazilian schoolchildren in the state of São Paulo
Authors: Grimm Sylvia , Frazão Paulo , Antunes José Leopoldo Ferreira , Castellanos Roberto Augusto , Narvai Paulo Capel
Published: May 2004

Abstract  – To describe the distribution of dental trauma in Brazilian schoolchildren and its association with demographic, environmental and clinical factors. A random sample of 73 243 schoolchildren's oral examination records from private and public units, selected from 131 cities within the state of São Paulo, Brazil, was analysed. Trauma was assessed based on international methodological standards prescribed by the World Health Organization for Oral Health Surveys (1997). Proportions obtained were compared between urban and rural schools, as well as between private and public units. Oral health status indices were estimated based on the decayed, missing and filled teeth (DMFT) index – the average number of decayed, missing and filled teeth; the proportion of caries‐free 5‐year‐old schoolchildren and anterior maxillary overjet among 12‐year‐old schoolchildren. The prevalence of dental trauma in anterior dentition was of 2.4, enrolling average 1.2 teeth per child. A rate of 2.4 impaired anterior teeth per thousand was obtained, upper central incisors being those that were most affected – 7.7 in every 10. Among 8‐ to 11‐year‐old children, the rates grew regularly. The proportion of dental trauma was significantly higher in boys than in girls (P < 0.01), and gender prevalence ratio was of 1.58 for boys. The results showed positive associations between dental trauma and caries‐free 5‐year‐old schoolchildren (P = 0.003), anterior maxillary overjet≥3 mm (P < 0.001), and private school as a socio‐economic proxy indicator (P = 0.048).
Species Interactions and the Evolution of Sex
Authors: Otto Sarah P. , Nuismer Scott L.
Published: May 2004

The Red Queen hypothesis posits that sex has evolved in response to the shifting adaptive landscape generated by the evolution of interacting species. Previous studies supporting the Red Queen hypothesis have considered a narrow region of parameter space and only a subset of ecological and genetic interactions. Here, we develop a population genetics model that circumscribes a broad array of ecological and genetic interactions among species and derive the first general analytical conditions for the impact of species interactions on the evolution of sex. Our results show that species interactions typically select against sex. We conclude that, although the Red Queen favors sex under certain circumstances, it alone does not account for the ubiquity of sex.
Continuous Particle Separation Through Deterministic Lateral Displacement
Authors: Huang Lotien Richard , Cox Edward C. , Austin Robert H. , Sturm James C.
Published: May 2004

We report on a microfluidic particle-separation device that makes use of the asymmetric bifurcation of laminar flow around obstacles. A particle chooses its path deterministically on the basis of its size. All particles of a given size follow equivalent migration paths, leading to high resolution. The microspheres of 0.8, 0.9, and 1.0 micrometers that were used to characterize the device were sorted in 40seconds with a resolution of ∼10nanometers, which was better than the time and resolution of conventional flow techniques. Bacterial artificial chromosomes could be separated in 10 minutes with a resolution of ∼12%.
Enhanced Open Ocean Storage of CO
2
from Shelf Sea Pumping
Authors: Thomas Helmuth , Bozec Yann , Elkalay Khalid , de Baar Hein J. W.
Published: May 2004

Seasonal field observations show that the North Sea, a Northern European shelf sea, is highly efficient in pumping carbon dioxide from the atmosphere to the North Atlantic Ocean. The bottom topography–controlled stratification separates production and respiration processes in the North Sea, causing a carbon dioxide increase in the subsurface layer that is ultimately exported to the North Atlantic Ocean. Globally extrapolated, the net uptake of carbon dioxide by coastal and marginal seas is about 20% of the world ocean's uptake of anthropogenic carbon dioxide, thus enhancing substantially the open ocean carbon dioxide storage.
Preference for Vibrational over Translational Energy in a Gas-Surface Reaction
Authors: Smith R. R. , Killelea D. R. , DelSesto D. F. , Utz A. L.
Published: May 2004

State-resolved gas-surface reactivity measurements revealed that vibrational excitation of ν
3
(the antisymmetric C-H stretch) activates methane dissociation more efficiently than does translational energy. Methane molecules in the vibrational ground state require 45 kilojoules per mole (kJ/mol) of translational energy to attain the same reactivity enhancement provided by 36 kJ/mol of ν
3
excitation. This result contradicts a key assumption underlying statistical theories of gas-surface reactivity and provides direct experimental evidence of the central role that vibrational energy can play in activating gas-surface reactions.
Role of NMDA Receptor Subtypes in Governing the Direction of Hippocampal Synaptic Plasticity
Authors: Liu Lidong , Wong Tak Pan , Pozza Mario F. , Lingenhoehl Kurt , Wang Yushan , Sheng Morgan , Auberson Yves P. , Wang Yu Tian
Published: May 2004

Activation of
N
-methyl-
d
-aspartate subtype glutamate receptors (NMDARs) is required for long-term potentiation (LTP) and long-term depression (LTD) of excitatory synaptic transmission at hippocampal CA1 synapses, the proposed cellular substrates of learning and memory. However, little is known about how activation of NMDARs leads to these two opposing forms of synaptic plasticity. Using hippocampal slice preparations, we showed that selectively blocking NMDARs that contain the NR2B subunit abolishes the induction of LTD but not LTP. In contrast, preferential inhibition of NR2A-containing NMDARs prevents the induction of LTP without affecting LTD production. These results demonstrate that distinct NMDAR subunits are critical factors that determine the polarity of synaptic plasticity.
AN APPROACH TO SOLVE SLAVNOV–TAYLOR IDENTITY IN D4 ${\mathcal N}=1$ SUPERGRAVITY
Authors: KONDRASHUK IGOR
Published: May 2004

We consider a particular solution to Slavnov–Taylor identity in four-dimensional supergravity. The consideration is performed for pure supergravity, no matter superfields are included. The solution is obtained by inserting dressing functions into ghost part of the classical action for supergravity. As a consequence, physical part of the effective action is local invariant with respect to diffeomorphism and structure groups of transformation for dressed effective superfields of vielbein and spin connection.
THE EFFECT OF SUPERSYMMETRIC CP PHASES ON $q\bar q$ ANNIHILATIONS INTO CHARGINOS AND NEUTRALINOS
Authors: AYDEMIR AYTEKIN , CANKOCAK KEREM , SEVER RAMAZAN
Published: May 2004

We compute the rates for [Formula: see text] annihilation into charginos and neutralinos by taking into account the effects of supersymmetric soft phases. In particular, the phase of the μ parameter gains direct accessibility via the production of dissimilar charginos and neutralinos. The phases of the trilinear soft masses do not have a significant effect on the cross-sections. Our results can be important for sparticle searches at the LHC.
ACOUSTIC STUDY ON POLYCRYSTALLINE Pr2-xCexCuO4(x=0 AND 0.15)
Authors: CHONG TET VUI , ABD-SHUKOR R.
Published: May 2004

The acoustic properties of Pr 2-x Ce x CuO 4(x=0 and 0.15) samples are measured using the pulsed-echo-overlap method between 5–10 MHz. An elastic anomaly signifying a lattice softening tendency towards lower temperatures is observed in the x=0 sample between 220–250 K for longitudinal velocities but not observed in the shear mode, nor the x=0.15 sample (both longitudinal and shear mode). The electron-phonon coupling constant is calculated. It is suggested that the softening tendency in the x=0 sample between 220–250 K is due to the weak structural distortion induced in the magnetic transition.
ALMOST RADIALLY-INVARIANT SYSTEMS CONTAINING ARBITRARY KNOTS AND LINKS
Authors: BANKS S. P. , DIAZ D.
Published: May 2004

In this paper we show that a system containing any knot or link can be directly constructed in a simple way. The system is not chaotic and can even contain wild knots.
ORIENTED SPATIAL PATTERN FORMATION IN A FOUR LAYER CMOS CELLULAR NEURAL NETWORK
Authors: SHI BERTRAM E.
Published: May 2004

Cellular neural networks have found applications both as a platform for high speed image processing, as well as a model for complex spatiotemporal dynamical phenomena. This paper describes spatial pattern formation in a CMOS VLSI implementation of a CNN. With four layers of 32×64 cells, this CNN contains the most recurrently interconnected 2D layers of any VLSI CNN implementation to date. With over 8000 cells, it is also one of the largest in terms of the total number of cells. The spatial patterns generated by this network are bands of activity with a preferred scale and orientation, both of which can be adjusted via external bias voltages. The VLSI implementation provides a physical substrate for experimenting with complex spatiotemporal phenomena in real time, while also being amenable to theoretical analysis. Our experimental characterization of the observed patterns are in excellent agreement with our theoretical predictions.
A NONLINEAR OSCILLATORS NETWORK DEVOTED TO IMAGE PROCESSING
Authors: MORFU S. , COMTE J. C.
Published: May 2004

A contrast enhancement and image inverting tool using a lattice of uncoupled nonlinear oscillators is proposed. We show theoretically and numerically that the gray scale picture contrast is strongly enhanced even if this one is initially very small. An image inversion can be also obtained in real time with the same Cellular Nonlinear Network (CNN) without reconfiguration of the network. A possible electronic implementation of this CNN is finally discussed.
GENERATION OF HOMOCLINIC OSCILLATION IN THE PHASE SYNCHRONIZATION REGIME IN COUPLED CHUA'S OSCILLATORS
Authors: DANA SYAMAL KUMAR , CHAKRABORTY SATYABRATA
Published: May 2004

An experimental method for generating homoclinic oscillations using two nonidentical Chua's oscillators coupled in unidirectional mode is described here. A homoclinic oscillation is obtained at the response oscillator in the weaker coupling limit of phase synchronization. Different phase locking phenomena of homoclinic oscillations with external periodic pulse have been observed when the frequency of the pulse is close to the natural frequency of the homoclinic oscillation or its subharmonics.
CATASTROPHE THEORETIC CLASSIFICATION OF NONLINEAR OSCILLATORS
Authors: KUZNETSOVA A. YU. , KUZNETSOV A. P. , KNUDSEN C. , MOSEKILDE E.
Published: May 2004

Catastrophe theory is employed to classify different types of nonlinear oscillators, basing on the complication of their potentials. By using Thom's catastrophe unfoldings as oscillator potentials, we have introduced more general models to describe the dynamics of nonlinear oscillators, differing from each other by the form of their potential wells and by the possibility of escape. Spreading the investigation in the space of the parameters of the potential function, we have revealed that our examples defined via Thom's catastrophe unfoldings have some type of universal properties in the context of forced oscillations. For oscillators with nonescaping solutions, we have detected such typical bifurcation structures as crossroad areas and spring areas, and have described the universal scenario of their evolution under the forcing amplitude variation. On increasing the potential function degree, the complexity of the charts of the dynamical regimes results from the repetition of the described bifurcation scenario. For oscillators with escaping solutions, such general properties were investigated, as dependence of the charts of the dynamical regimes and the basins on the parameters of the potential function. We have observed that these properties are typical in a broad range of the control parameters.
NONLINEAR ANALYSIS OF A NETWORK OF THREE CONTINUOUS STIRRED TANK REACTORS WITH PERIODIC FEED SWITCHING: SYMMETRY AND SYMMETRY-BREAKING
Authors: RUSSO LUCIA , CRESCITELLI SILVESTRO , MANCUSI ERASMO , MAFFETTONE PIER LUCA
Published: May 2004

The spatiotemporal symmetry properties of a periodically forced network of three Continuous Stirred Tank Reactors are assessed. The symmetry is induced to the system by a cyclic switching of the feed and discharge positions. The symmetry properties imply that the Poincaré map is the third iterate of another nonstroboscopic map. This feature is here used to characterize the symmetry of the regime solutions, and to carry out bifurcation analysis. Possible bifurcation scenarios and, in particular, symmetry-breaking bifurcations are discussed. As the switch time is varied, different transitions have been identified: among the others, an important role in the birth of asymmetric regimes is played by frequency-locking phenomena. In addition, different routes to chaotic regimes (both symmetric and asymmetric) are reported.
PERIODIC SOLUTIONS FOR A FOURTH-ORDER EQUATION AND APPLICATIONS IN A MODEL OF STRUCTURAL MECHANICS
Authors: HU XIAOLI , LI JIBIN
Published: May 2004

By developing topological shooting methods, the existence of single-humped periodic solutions and homoclinic orbit for a class of fourth-order ordinary differential equations is obtained, under some general conditions. Using these strict mathematical conclusions to a model of the deflection patterns of elastic struts resting on elastic foundations, the existence of single-humped periodic solutions which have been found by asymptotical and numerical methods is determined. An estimation of the half-period of the periodic solutions is also given.
ENTROPY OF MAPS WITH HORIZONTAL GAPS
Authors: MISIUREWICZ MICHAŁ
Published: May 2004

We study the behavior of topological entropy in one-parameter families of interval maps obtained from a continuous map f by truncating it at the level depending on the parameter. When f is piecewise monotone, the entropy function has the devil's staircase structure.
ON THE CONJUGACY PROBLEM OF POSITIVE BRAIDS
Authors: ELRIFAI E. A. , BENKHALIFA M.
Published: May 2004

In the symmetric group Sn, we introduced the notion of crossing and linking numbers to each permutation. Then a unique factorization of a permutation is given due to its crossing number of its factors and how the factors are linked. Consequently we introduced a matrix associated to each permutation, which we used it as a tool to prove that positive braids with different matrices are not conjugate braids. Up to n≤5 it is proved that two positive permutation braids are conjugate if and only if they have the same matrix, and a complete calculation of these matrices with the associated link type is given.
THE SPACE OF IRREDUCIBLE SU(2) REPRESENTATIONS OF THE TWIST KNOTS
Authors: UYGUR TANGÜL , AZCAN HÜSEYİN
Published: May 2004

In this work we classify the space of irreducible SU(2) representations of the groups of the twist knots by means of a geometric method which is generalizable to all the 2-bridge knots.
TANGLE SUM AND CONSTRUCTIBLE SPHERES
Authors: HACHIMORI MASAHIRO , SHIMOKAWA KOYA
Published: May 2004

In this paper we discuss the relation between the combinatorial properties of cell decompositions of 3-spheres and the bridge index of knots contained in their 1-skeletons. The main result is to solve the conjecture of Ehrenborg and Hachimori which states that for a knot K in the 1-skeleton of a constructible 3-sphere satisfies e(K)≥2b(K), where e(K) is the number of edges K consists of, and b(K) is the bridge index of K. The key tool is a sharp inequality of the bridge index of tangles in relation with "tangle sum" operation, which improves the primitive rough inequality used by Eherenborg and Hachimori. We also present an application of our new tangle sum inequality to improve Armentrout's result on the relation between shellability of cell decompositions of 3-spheres and the bridge index of knots in a general position to their 2-skeletons.
PURE-BRAIDED HOPF ALGEBRAS AND KNOT INVARIANTS
Authors: STAIC MIHAI D.
Published: May 2004

In this paper we construct representations for the pure braid group using Hopf algebra techniques. From this representations we obtain invariants for knots.
COUNTING SL2(Fq)-REPRESENTATIONS OF TORUS KNOT GROUPS
Authors: LI WEIPING , XU LIANG
Published: May 2004

In this paper, we count the number of SL2(Fq)-representations of torus knot group up to conjugacy. For the finite field Fq case, the counting methods are interested in its own right. Explicit formulae of the effective counting are given in this paper.
ON THE COMBINATORIAL PROPERTIES OF k-ARY n-CUBES
Authors: SARBAZI-AZAD H. , OULD-KHAOUA M. , MACKENZIE L. M. , AKL S. G.
Published: May 2004

The k-ary n-cube has been used as the underlying topology for most practical multicomputers, and has been extensively studied in the past. In this paper, we investigate some properties of this network. In particular, we study the problem of finding the number of nodes located i hops away from a given node (surface area) and the number of nodes located within i hops away from a given node (volume) in both the unidirectional and bidirectional k-ary n-cube, and have derived exact expressions calculating these numbers. These results are very useful when studying, for example, the spanning tree structure of the k-ary n-cube and the problem of resource placement in this network.
The mechanism of EDHF-mediated responses in subcutaneous small arteries from healthy pregnant women
Authors: Luksha Leonid , Nisell Henry , Kublickiene Karolina
Published: May 2004

We studied the importance of endothelium-derived hyperpolarizing factor (EDHF) vs. nitric oxide (NO) and prostacyclin (PGI2) in bradykinin (BK)-induced relaxation in isolated small subcutaneous arteries from normal pregnant women. We also explored the contribution of cytochrome P-450 (CYP450) product of arachidonic acid (AA) metabolism, hydrogen peroxide (H2O2), and gap junctions that have been suggested to be involved in EDHF-mediated responses. Isolated arteries obtained from subcutaneous fat biopsies of normal pregnant women ( n = 30) undergoing planned cesarean section were mounted in a wire-myography system. In norepinephrine-constricted vessels, incubation with NG-nitro-l-arginine methyl ester (l-NAME) resulted in a significant reduction in relaxation to BK. Simultaneous incubation with l-NAME and indomethacin failed to modify this response further. BK-mediated dilatation in the presence of K+-modified solution was decreased to similar level as obtained after incubation with l-NAME. Incubation with l-NAME abolished BK-induced responses in K+-modified solution. Sulfaphenazole, a specific inhibitor of CYP450 epoxygenase, and catalase (an enzyme that decomposes H2O2) did not affect the EDHF-mediated relaxation because concentration-response curves to BK were similar in arteries after incubation with l-NAME vs. l-NAME + sulfaphenazole and l-NAME + catalase. The inhibitor of gap junctions, 18α-glycyrrhetinic acid, significantly reduced BK-mediated relaxation both without and with incubation with l-NAME. We found that both NO and EDHF, but not PGI2, are involved in the endothelium-dependent dilatation to BK. BK-induced relaxation is almost equally mediated by NO and EDHF. CYP450 epoxygenase metabolites of AA or H2O2do not account for EDHF-mediated response; however, gap junctions are involved in the EDHF-mediated responses to BK in subcutaneous small arteries in normal pregnancy.
A mechanism underlying mature-onset obesity: evidence from the hyperphagic phenotype of brain-derived neurotrophic factor mutants
Authors: Fox Edward A. , Byerly Mardi S.
Published: May 2004

Mice deficient in brain-derived neurotrophic factor (BDNF) develop mature-onset obesity, primarily due to overeating. To gain insight into the mechanism of this hyperphagia, we characterized food intake, body weight, meal pattern, and meal microstructure in young and mature mice fed balanced or high-fat diets. Hyperphagia and obesity occurred in mature but not young BDNF mutants fed a balanced diet. This hyperphagia was mediated by increased meal number, which was associated with normal meal size, meal duration, and satiety ratio. In contrast, the high-fat diet induced premature development of hyperphagia and obesity in young BDNF mutants and a similar magnitude hyperphagia in mature mutants. This hyperphagia was supported by increased meal size and was accompanied by a reduced satiety ratio. Thus the mechanism underlying hyperphagia was present before significant weight gain, but whether it occurred, and whether meal frequency or meal size was altered to support it, was modulated by a process associated with aging and by diet properties. Meal pattern changes associated with the balanced diet suggested meal initiation, and the oropharyngeal positive feedback that drives feeding, were enhanced and might have contributed to overeating in BDNF mutants, whereas negative feedback was normal. Consistent with this hypothesis, meal microstructure revealed that all hyperphagic mutant groups exhibited increased intake rates at meal onset. Therefore, the central nervous system targets of BDNF actions may include orosensory brain stem neurons that process and transmit positive feedback or forebrain neurons that modulate its strength.
Neuroglobin: A Respiratory Protein of the Nervous System
Authors: Burmester Thorsten , Hankeln Thomas
Published: May 2004

Nerve tissues exhibit some of the highest oxygen consumption rates found in the body. Neuroglobin, a heme protein distantly related to hemoglobin, is thought to enhance the supply of oxygen to the neurons, the eye, and some endocrine tissues. Neuroglobin may promote neuronal survival under hypoxic conditions as they occur, for example, in stroke.
Caribbean Bodies, Migrations, and Spaces of Resistance
Authors: Tabares Vivian Martínez
Published: May 2004

An analysis of three closely related solo performances by artists from the Caribbean. The works of Puerto Rican Javier Cardona, Dominican Waddys Jáques, and Cuban Marianela Boán are hybrid expressions that make no distinction between theatre and dance. These artists ignore linear or continuous time, actively consider the audience, and propose a subversive and intertextual linguistic game that appropriates popular language and culture, merging these into a new performative norm.
Clinically important deep vein thrombosis in the intensive care unit: a survey of intensivists
Authors: Cook Deborah , Meade Maureen , Guyatt Gordon , Griffith Lauren , Granton John , Geerts William , Crowther Mark ,   the Canadian Critical Care Trials Group
Published: May 2004

Introduction

Outside the intensive care unit (ICU), clinically important deep vein thrombosis (DVT) is usually defined as a symptomatic event that leads to objective radiologic confirmation and subsequent treatment. The objective of the present survey is to identify the patient factors and radiologic features of lower limb DVT that intensivists consider more or less likely to make a DVT clinically important in ICU patients.

Methods

Our definition of clinically important DVT was a DVT likely to result in short-term or long-term morbidity or mortality if left untreated, as opposed to a DVT that is unlikely to have important consequences. We asked respondents to indicate the likelihood that patient factors and ultrasonographic features make a DVT clinically important using a five-point scale (from 1 = much less likely to 5 = much more likely).

Results

Of the 71 Canadian intensivists who responded, 70 (99%) rated three patient factors as most likely to make a DVT clinically important: clinical suspicion of pulmonary embolism (mean score 4.6), acute or chronic cardiopulmonary morbidity that might limit a patient's ability to tolerate pulmonary embolism (score 4.5), and leg symptoms (score 4.2). Of the ultrasound features, proximal (score 4.7), large (score 4.2), and totally occlusive (score 3.9) thrombi were considered the three most important.

Conclusion

When labeling a DVT as clinically important, intensivists rely on different patient specific factors and thrombus characteristics than are used to assess the clinical importance of DVT outside the ICU. The clinical importance of DVT is influenced by unique factors such as cardiopulmonary reserve among mechanically ventilated patients.
Age Is a Risk Factor for Chemotherapy-Induced Hepatopathy With Vincristine, Dactinomycin, and Cyclophosphamide
Authors: Arndt C. , Hawkins D. , Anderson J.R. , Breitfeld P. , Womer R. , Meyer W.
Published: May 2004

Purpose

To evaluate the spectrum of and determine the risk factors for the development of liver toxicity (hepatopathy) after therapy with vincristine, dactinomycin, and cyclophosphamide (VAC) for rhabdomyosarcoma in children and adolescents.

Patients and Methods

We prospectively captured all events of hepatopathy occurring on the ongoing Children's Oncology Group intermediate risk protocol, D9803, for children with rhabdomyosarcoma. Patients enrolled onto this trial were randomly assigned to receive either VAC alone or VAC alternating with vincristine, topotecan, and cyclophosphamide. In addition, we reviewed the toxicity database and requested additional information for all patients with elevated bilirubin or transaminase levels. Risk factors were analyzed.

Results

Of 339 patients enrolled through August 2002, 18 developed hepatopathy. All events were captured by mandated toxicity reporting and filing of MedWatch forms, with no additional cases found after the additional search of the database. Four children died after developing this toxicity. All cases occurred after cycles of VAC (n = 16) or vincristine and cyclophosphamide with concomitant abdominal radiotherapy (n = 2). The onset of hepatopathy was 5 to 16 days from the start of a treatment cycle. For the 89 patients under 36 months of age, the risk of hepatopathy was 15%, with two deaths. For the 239 children 3 years of age or older, the risk for hepatopathy was 4%, with two deaths.

Conclusion

The greatest risk factor for development of hepatopathy after VAC therapy was age. Dose modifications for younger children receiving VAC therapy are recommended.