bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetic instability of flute oscillations
Authors: Kopecký V. 
Published: January 2011

The author considers the effect of resonance particles drifting under the influence of magnetic field inhomogeneity with a velocity close to the phase velocity of flute oscillations on those oscillations. He investigates the instability of these oscillations at densities below the critical density of the hydrodynamic flute instability Ra/d2 ≪ 1 (R – radius of curvature of the magnetic field lines, a – transverse dimension of the plasma, d – Debye radius).
It is shown that, when resonance particles are present, the branch of oscillations with frequency (ω0 – ionic plasma frequency, ωc – ionic cyclotron frequency, k – transverse wave number) is always unstable. For an ion transverse velocity distribution function having the form of a δ-function with an admixture of hot ions, it is shown that the branch of oscillations with a frequency only slightly dependent on density and close to (v0 – mean ion velocity) is also unstable. Both instabilities also occur in the hydrodynamically stable case; i.e. when the magnetic field lines are convex with respect to the plasma.
Influence of ballooning effects on plasma stability in closed systems
Authors: Shafranov V. D. , Yurchenko E.I. 
Published: January 2011

A general criterion of hydromagnetic plasma stability in the infinite electrical conductivity approximation is applied to smooth closed systems. As in the pioneering work of Mercier, the authors use the method of expansion with respect to the deviation from the magnetic axis. The effects of ballooning instability and of magnetic well deepening due to ballooninginduced stretching of the plasma column are clearly distinguished in this criterion. The above effects cancel out with an accuracy to within the square of the ellipticity of the magnetic surface cross-sections. Even in magnetic systems with a comparatively shallow magnetic well, ballooning instability does not therefore lead to a serious limitation on plasma pressure.
The authors present estimates of the critical plasma pressure for a two-turn stellarator and for systems with helical and axial symmetry.
Gyroresonant particle acceleration in a non-uniform magnetostatic field
Authors: Canobbio E. 
Published: January 2011

Particle motion in inhomogeneous magnetostatic and high-frequency fields at the gyroresonance is studied in the limit of a large number of particle revolutions in the resonance region. The role played by the magnetic mirror, Doppler and relativistic effects, wave attenuation and radiation pressure on particle acceleration is discussed. The time dependence of the orbital magnetic flux, the velocity along the magnetic lines of force and the width of the resonance region are calculated. An upper limit is found for the energy of the particle, when the effect of the magnetic field of the wave partially compensates for the change in mass with energy.The non-linear method we use is exact in the limit of many revolutions. It generalizes the results established by C.S. Roberts and S.J. Buchsbaum in a special case, to the more complex situation proposed by T. Consoli for injecting, accelerating and confining a hot plasma in a magnetic trap. A number of numerical examples are presented for various conditions. The energy transfer to the particles at the parametric resonances is also investigated.The space charge field which develops along the magnetic lines of force in a plasma accelerating structure is taken into account in the equations from the very beginning by assuming (Consoli) that the electron guiding centres move with the velocity of the ions.
Non-linear skin effect in a conducting cylinder
Authors: Breus S.N. , Kurdyumov V.N. 
Published: January 2011

The paper examines the penetration into a plasma cylinder of a quasi-stationary electromagnetic field excited by a wave of azimuthal surface current travelling parallel with the cylinder axis and located at some distance from the surface of the plasma. Since in this instance the variable magnetic field is considerably higher than the electric field its influence on the movement of particles in the plasma was taken into account. Within the limits of a hydrodynamic approximation this factor could be reduced to the inclusion of the Hall current in Ohm's law (σ/enc) [j⃗H⃗]. A solution to the resulting system of nonlinear partial differential equations was found by using a computer programme somewhat analogous to the physical process by which field equilibrium distributions are established in a plasma.
The dependence of all physical magnitudes on two parameters was studied: the conductivity of the plasma o and the ratio Ω of the Hall current to the conduction current.
Allowance for non-linear effects leads to the appearance of a constant component of the longitudinal current (the carrier current), whose density never exceeds, at any point of the cylinder cross-section, the limiting value corresponding to the movement of all electrons at the phase velocity of the wave. A leakage of current towards the inner region of the plasma cylinder takes place and closed lines of current form in the cross-sections φ = const. The depth of field penetration increases with increased non-linearity, while at high plasma conductivity values the penetration depth is determined only by the value of Ω. Dissipation losses in the plasma are to all practical purposes independent of Ω.
The plasmascope: its operational features, design and applications
Authors: Dobrokhotov E.I. , Zharinov A.V. , Moskalev I.N. , Petrov D.P. 
Published: January 2011

The authors analyse the specific properties of the plasmascope as a device for investigating the processes which occur in a closed-end plasma chamber immersed in a magnetic field. They indicate its advantages and possibilities, and assess how much information can be obtained with it.
The design elements of the plasmascope are described, together with certain techniques employed in its construction.
The results are presented of plasmascope experiments with a low-temperature plasma obtained by means of gaseous discharge with an incandescent cathode. On the basis of these results it is possible to estimate the directed-motion velocities of the plasma, the plasma potential and the electric fields, and to obtain a picture of the instantaneous plasma density distribution over the transverse cross-section of the discharge. It is shown that the characteristic states of a discharge can be identified with the help of plasmagrams.
Inductive lenses for improved magnetic field symmetry in a corrugated theta-pinch coil
Authors: Hartz F. , Junker J. , Pohl F. , Wolf G.H. 
Published: January 2011

The magnetic field distribution of corrugated theta-pinch coils is measured in an analogue experiment (experimental error 0.05%) in order to determine the perturbation of the rotational symmetry induced by the current feed slot.
The maximum deviations from rotational symmetry are found near the coil surface around the current feed slot. They have a value of a few per cent and are proportional to the width of the current feed slot. The perturbations decrease towards the coil axis to a few tenths per cent only.
The distribution of a locally varying inductance of the current transmission line is computed and applied by moulding inductive lenses into the transmission line plates. The influence of the inductive lenses is measured. Within a radial region of about 1/2 of the coil radius the perturbations are found to be reduced to the level of the experimental error. The residual perturbations outside this region are mainly attributed to the limited space available for the application of the inductive lenses in the transmission line system.
Parametric excitation of ion-sound instability in a magnetized plasma located in a high-frequency electric field
Authors: Nekrasov F.M. 
Published: January 2011

The author investigates the stability of a magnetized non-isothermal (Te ≫ Ti) plasma in an alternating electric field when the field frequency Ω0 is close to the frequency of the ion-sound oscillations of the plasma.
The amplitude of the oscillatory velocity of electrons in a h.f. field is assumed to be small compared with their thermal velocity (u0 ≪ vTe
). It is shown that, for perturbations with wave number kz satisfying the resonance condition there exists in such a plasma an instability with a growth rate .
The width of the instability zone is determined in the kinetic and hydrodynamic approximations. In the hydrodynamic approximation, if one does not allow for dissipation, there is instability however small the value of . If one allows for collisionless kinetic damping of the oscillations on the electrons, the instability develops only when u0 exceeds come critical value ∼ vTe
(me/Mi)¼.
Self-consistent propagation of an electromagnetic wave and power absorption at the electron gyroresonance in a plasma immersed in a non-uniform magnetic field
Authors: Brambilla M. 
Published: January 2011

The self-consistent equation for the propagation of a right-hand polarized electromagnetic wave in a cold plasma immersed in a non-uniform magnetic field is solved exactly under the assumption that the parallel electron velocity v‖ is constant. This equation , which properly takes into account the dissipative component of the induced current, leads to expressions for the reflection, transmission and absorption coefficients which reduce to those obtained by Stix and Budden in the limit v‖ = 0. The reflection coefficient is found to vanish identically, while the absorption is almost complete if the density is sufficiently high.
An approximate solution is then obtained for the case where the non-linear effects in the resonance zone (axial acceleration, relativistic change of mass) cannot be neglected. It is found that these effects can give rise to substantial wave reflection. Thus at high h.f. power the electromagnetic energy is effectively coupled to the plasma only if the density is high enough to reduce the intensity of the electric field in the resonance region to a level such that the linear theory applies.
The effect of neuromuscular blockade on mask ventilation
Authors: Warters R. D. , Szabo T. A. , Spinale F. G. , DeSantis S. M. , Reves J. G. 
Published: January 2011

SummaryWe wished to test the hypothesis that neuromuscular blockade facilitates mask ventilation. In order reliably and reproducibly to assess the efficiency of mask ventilation, we developed a novel grading scale (Warters scale), based on attempts to generate a standardised tidal volume. Following induction of general anaesthesia, a blinded anaesthesia provider assessed mask ventilation in 90 patients using our novel grading scale. The non‐blinded anaesthesiologist then randomly administered rocuronium or normal saline. After 2 min, mask ventilation was reassessed by the blinded practitioner. Rocuronium significantly improved ventilation scores on the Warters scale (mean (SD) 2.3 (1.6) vs 1.2 (0.9), p < 0.001). In a subgroup of patients with a baseline Warters scale value of > 3 (i.e. difficult to mask ventilate; n = 14), the ventilation scores also showed significant improvement (4.2 (1.2) vs 1.9 (1.0), p = 0.0002). Saline administration had no effect on ventilation scores. Our data indicate that neuromuscular blockade facilitates mask ventilation. We discuss the implications of this finding for unexpected difficult airway management and for the practice of confirming adequate mask ventilation before the administration of neuromuscular blockade.
Characterization of the PRNP gene locus in Chios dairy sheep and its association with milk production and reproduction traits
Authors: Psifidi A. , Basdagianni Z. , Dovas C. I. , Arsenos G. , Sinapis E. , Papanastassopoulou M. , Banos G. 
Published: January 2011

SummaryThe objective of this study was to examine the prion protein gene locus (PRNP) in Chios sheep. PRNP is linked with scrapie resistance in small ruminants. Here, its impact on milk production (test‐day and total lactation yield) and reproduction (age at first lambing, conception rate at first service, and prolificacy) was assessed. Genotyping at codons 136, 154 and 171 (classical scrapie) and 141 (atypical scrapie) was performed using DNA from milk somatic cells and PCR‐RFLP analysis. A total of 1013 Chios ewes raised in 23 flocks were used. This constituted a random sample of the national breeding population. A total of 15 genotypes and 6 alleles linked to codons 136, 154 and 171 were detected. All animals were homozygous for the leucine allele at codon 141. Linear mixed models were used to assess the impact of PRNP genotypes and alleles on milk production and reproduction traits. The TRQ allele, whose association with such traits was assessed for the first time, had an adverse effect on age at first lambing. All other PRNP alleles, including ARR, which is associated with increased resistance to classical scrapie, had no significant effect on the traits studied. No significant associations of the PRNP genotypes with production and reproduction traits were observed. It was concluded that selection for scrapie‐resistant sheep is not expected to affect the ongoing breeding programme that aims to enhance the milk yield and reproduction of the Chios breed.
Relationships and betrayal among young women: theoretical perspectives on adolescent dating abuse
Authors: Burton Candace W. , Halpern‐Felsher Bonnie , Rankin Sally H. , Rehm Roberta S. , Humphreys Janice C. 
Published: January 2011

burton c.w., halpern‐felsher b., rankin s.h., rehm r.s. & humphreys j.c. (2011) Relationships and betrayal among young women: theoretical perspectives on adolescent dating abuse. Journal of Advanced Nursing67(6), 1393–1405.AbstractAims.  Adolescent dating abuse is not specifically described by any current nursing theory, and this article presents discussion of some existing theories that could inform a nursing theory of adolescent dating abuse. To account for the effects of gender, this discussion is limited to young women.Background.  Adolescent dating abuse is an important and understudied international issue for nursing. Theoretical frameworks can support development of nursing scholarship for such issues. No single theory yet exists in nursing to explain the experiences and health ramifications of dating abuse among young women.Data sources.  A summary table of theories is provided. Literature was gathered via database search and bibliographic snowballing from reference lists of relevant articles. Included literature dates from 1982 through 2010.Discussion.  Theories of relationship formation and function are discussed, including attachment, investment, feminist and gender role conflict theories. Betrayal trauma theory is considered as a mechanism of injury following an abusive dating experience.Implications for nursing.  Gender, relationship and adolescence combine in a complex developmental moment for young women. To improve nursing care for those at risk for or in the throes of abusive relationships, it is critical to develop specific nursing approaches to understanding these relationships.Conclusion.  Existing theories related to relationship and traumatic experiences can be combined in the development of a nursing theory of adolescent dating abuse among young women.
Factors affecting nurse practitioner role implementation in Canadian practice settings: an integrative review
Authors: Sangster‐Gormley Esther , Martin‐Misener Ruth , Downe‐Wamboldt Barbara , DiCenso Alba 
Published: January 2011

sangster‐gormley e., martin‐misener r., downe‐wamboldt b. & dicenso a. (2011) Factors affecting nurse practitioner role implementation in Canadian practice settings: an integrative review. Journal of Advanced Nursing67(6), 1178–1190.AbstractAim.  To review the literature about the Canadian experience with nurse practitioner role implementation and identify influencing factors.Background.  Although nurse practitioners have been in existence for more than 40 years, their integration into healthcare systems has been challenging. While frameworks exist to guide implementation of these roles, clear identification of factors influencing role implementation may inform best practices. Given that Canada has witnessed considerable growth in nurse practitioner positions in the past decade, an exploration of its experience with role implementation is timely.Data sources.  A review of Canadian literature from 1997 to 2010 was conducted. Electronic databases including CINAHL, Cochrane Database of Systematic Reviews, Health Source: Nursing Academic Edition, Medline, Social Science Index, PubMed, Web of Science and PsychINFO and government and professional organization websites were searched.Methods.  An integrative review was performed guided by Whittemore and Knafl’s method.Results.  Ten published studies and two provincial reports were included. Numerous facilitators and barriers to implementation were identified and analysed for themes. Three concepts influencing implementation emerged: involvement, acceptance and intention. Involvement is defined as stakeholders actively participating in the early stages of implementation. Acceptance is recognition and willingness to work with nurse practitioner. Intention relates to how the role is defined.Conclusion. This integrative review revealed three factors that influence nurse practitioner role implementation in Canada: involvement, acceptance and intention. Strategies to enhance these factors may inform best practice role implementation processes.
Psychometric validity of the Problem‐Focused Style of Coping scale: in relation to self‐efficacy and life satisfaction among nursing staff in Taiwan
Authors: Chang Yuhsuan 
Published: January 2011

chang y. (2011) Psychometric validity of the Problem‐Focused Style of Coping scale: in relation to self‐efficacy and life satisfaction among nursing staff in Taiwan. Journal of Advanced Nursing67(7), 1625–1631.AbstractAims.  This paper is a report of a study of psychometric properties of the Problem‐Focused Style of Coping‐Chinese version questionnaire.Background.  Coping with stress is an important topic in the 21th century, which deserves further attention. Although a variety of instruments have emerged to assess an individual’s coping responses to stress, research suggests that numerous problems are associated with the current measurements. Since most coping scales are criticized as lacking valid estimates across occupational samples and cultures, there is an immediate need to develop a reliable and valid coping‐style scale.Method.  The study used a convenience sample and a sampling frame consisting of 307 nurses from different medical units in two regional hospitals in Taiwan. The data collection period was from May 2009 to June 2009. Exploratory factor analyses and reliability estimates were calculated.Results.  The factor analysis revealed three coping factors: reflective, suppressive and reactive. All reliability and validity estimates were satisfactory.Conclusion.  The Problem‐Focused Style of Coping‐Chinese version questionnaire is a valid and reliable measure of nurses’ dispositional coping style and can be used for educational training programmes to enhance nurses’ stress management skills.
Why replication is important in landscape genetics: American black bear in the Rocky Mountains
Authors: SHORT BULL R. A. , CUSHMAN S. A. , MACE R. , CHILTON T. , KENDALL K. C. , LANDGUTH E. L. , SCHWARTZ M.K. , MCKELVEY K. , ALLENDORF FRED W. , LUIKART G. 
Published: January 2011

AbstractWe investigated how landscape features influence gene flow of black bears by testing the relative support for 36 alternative landscape resistance hypotheses, including isolation by distance (IBD) in each of 12 study areas in the north central U.S. Rocky Mountains. The study areas all contained the same basic elements, but differed in extent of forest fragmentation, altitude, variation in elevation and road coverage. In all but one of the study areas, isolation by landscape resistance was more supported than IBD suggesting gene flow is likely influenced by elevation, forest cover, and roads. However, the landscape features influencing gene flow varied among study areas. Using subsets of loci usually gave models with the very similar landscape features influencing gene flow as with all loci, suggesting the landscape features influencing gene flow were correctly identified. To test if the cause of the variability of supported landscape features in study areas resulted from landscape differences among study areas, we conducted a limiting factor analysis. We found that features were supported in landscape models only when the features were highly variable. This is perhaps not surprising but suggests an important cautionary note – that if landscape features are not found to influence gene flow, researchers should not automatically conclude that the features are unimportant to the species’ movement and gene flow. Failure to investigate multiple study areas that have a range of variability in landscape features could cause misleading inferences about which landscape features generally limit gene flow. This could lead to potentially erroneous identification of corridors and barriers if models are transferred between areas with different landscape characteristics.
Assessing the complex architecture of polygenic traits in diverged yeast populations
Authors: CUBILLOS FRANCISCO A. , BILLI ELEONORA , ZÖRGÖ ENIKÖ , PARTS LEOPOLD , FARGIER PATRICK , OMHOLT STIG , BLOMBERG ANDERS , WARRINGER JONAS , LOUIS EDWARD J. , LITI GIANNI 
Published: January 2011

AbstractPhenotypic variation arising from populations adapting to different niches has a complex underlying genetic architecture. A major challenge in modern biology is to identify the causative variants driving phenotypic variation. Recently, the baker’s yeast, Saccharomyces cerevisiae has emerged as a powerful model for dissecting complex traits. However, past studies using a laboratory strain were unable to reveal the complete architecture of polygenic traits. Here, we present a linkage study using 576 recombinant strains obtained from crosses of isolates representative of the major lineages. The meiotic recombinational landscape appears largely conserved between populations; however, strain‐specific hotspots were also detected. Quantitative measurements of growth in 23 distinct ecologically relevant environments show that our recombinant population recapitulates most of the standing phenotypic variation described in the species. Linkage analysis detected an average of 6.3 distinct QTLs for each condition tested in all crosses, explaining on average 39% of the phenotypic variation. The QTLs detected are not constrained to a small number of loci, and the majority are specific to a single cross‐combination and to a specific environment. Moreover, crosses between strains of similar phenotypes generate greater variation in the offspring, suggesting the presence of many antagonistic alleles and epistatic interactions. We found that subtelomeric regions play a key role in defining individual quantitative variation, emphasizing the importance of the adaptive nature of these regions in natural populations. This set of recombinant strains is a powerful tool for investigating the complex architecture of polygenic traits.