1,032 research outputs found
Evaluation of induced polyploidy in Acacia mearnsii through stomatal counts and guard cell measurements
The black wattle, Acacia mearnsii, an important commercially grown tree in South Africa, is considered one of the top alien invader species within indigenous vegetation because of its abundant seed production and dispersal. One of the aims at the Institute for Commercial Forestry Research (ICFR) is to restrict the spread of wattle outside plantation boundaries. Current consideration has been given to polyploids, which could be semi-sterile or even sterile due to irregular meiosis that results in infertile gametes. Autotetraploids were produced by the scarification of seeds and treatment with different colchicine concentrations (0%, 0.01%, 0.03%, 0.05%, 0.07% and 0.1%) for various times (6h, 12h, 24h and 48h), rinsed and germinated in the dark at 25°C to induce chromosome doubling. Tetraploidy was successfully induced by applying 0.01% colchicine to chipped seeds for a period of 6h. This result was validated through percentage germination (90%), average seedling growth rate (16mm), seedling height (20mm) and percentage seedling survival (61%). Chromosome doubling was confirmed by stomatal guard cell length (39.9 ± 0.4 (SE) mm) and stomatal frequency measurements (12.0 ± 0.5 (SE))
A framework for understanding the factors influencing pair programming success
Pair programming is one of the more controversial aspects of several Agile system development methods, in particular eXtreme Programming (XP). Various studies have assessed factors that either drive the success or suggest advantages (and disadvantages) of pair programming.
In this exploratory study the literature on pair programming is examined and factors distilled. These factors are then compared and contrasted with those discovered in our recent Delphi study of pair programming.
Gallis et al. (2003) have proposed an initial framework aimed at providing a comprehensive identification of the major factors impacting team programming situations including pair programming. However, this
study demonstrates that the framework should be extended to include an additional category of factors that relate to organizational matters. These factors will be further refined, and used to develop and empirically evaluate a conceptual model of pair programming (success)
Adherence to clinical practice guidelines among three primary contact professions: A best evidence synthesis of the literature for the management of acute and subacute low back pain
Aim: To determine adherence to clinical practice guidelines in the medical, physiotherapy and chiropractic professions for acute and subacute mechanical low back pain through best-evidence synthesis of the healthcare literature.
Methods: A structured best-evidence synthesis of the relevant literature through a literature search of relevant databases for peer-reviewed papers on adherence to clinical practice guidelines from 1995 to 2013. Inclusion of papers was based on selection criteria and appraisal by two reviewers who independently applied a modified Downs & Black appraisal tool. The appraised papers were summarized in tabular form and analysed by the authors.
Results: The literature search retrieved 23 potentially relevant papers that were evaluated for methodological quality, of which 11 studies met the inclusion criteria. The main finding was that no profession in the study consistently attained an overall high concordance rating. Of the three professions examined, 73% of chiropractors adhered to current clinical practice guidelines, followed by physiotherapists (62%) and then medical practitioners (52%).
Conclusions: This review showed that quality papers in this area of research are very limited. Notwithstanding, chiropractors appear to adhere to clinical practice guidelines more so than physiotherapists and medical practitioners, although there is scope for improvement across all three professions
Observation and Modeling of the Solar-Cycle Variation of the Meridional Flow
We present independent observations of the solar-cycle variation of flows
near the solar surface and at a depth of about 60 Mm, in the latitude range
. We show that the time-varying components of the meridional flow
at these two depths have opposite sign, while the time-varying components of
the zonal flow are in phase. This is in agreement with previous results. We
then investigate whether the observations are consistent with a theoretical
model of solar-cycle dependent meridional circulation based on a flux-transport
dynamo combined with a geostrophic flow caused by increased radiative loss in
the active region belt (the only existing quantitative model). We find that the
model and the data are in qualitative agreement, although the amplitude of the
solar-cycle variation of the meridional flow at 60 Mm is underestimated by the
model.Comment: To be published in Solar Physcis Topical Issue "Helioseismology,
Asteroseismology, and MHD Connections
The National Eye Institute Visual Function Questionnaire: Experience of the ONTT
purpose. To describe the health-related quality of life, measured with the National Eye Institute Visual Function Questionnaire (NEI–VFQ), of patients several years after the onset of optic neuritis, according to their neurologic and visual status; to assess the relationship between the NEI–VFQ subscales and clinical measures of visual function; and to assess the internal consistency reliability of the NEI–VFQ subscales. methods. The NEI–VFQ was administered to 244 patients 5 to 8 years after treatment for an episode of acute optic neuritis as part of the Optic Neuritis Treatment Trial. Visual acuity, visual field, contrast sensitivity, and color vision were measured at the same time as questionnaire completion. results. The NEI–VFQ scores generally were lower than those reported for a disease-free group. Reported dysfunction was greater when multiple sclerosis was present and when visual acuity was abnormal, supporting the construct validity of the NEI–VFQ. Rank correlations between the NEI–VFQ subscales and clinical measures of visual function were moderate at best. Internal consistency reliability was generally high for most of the NEI–VFQ subscales. conclusions. These findings add support to the use of the NEI–VFQ as a valuable measure of self-reported visual impairment
Deformation effects in Ni nuclei produced in Si+Si at 112 MeV
Velocity and energy spectra of the light charged particles (protons and
-particles) emitted in the Si(E = 112 MeV) + Si
reaction have been measured at the Strasbourg VIVITRON Tandem facility. The
ICARE charged particle multidetector array was used to obtain exclusive spectra
of the light particles in the angular range 15 - 150 degree and to determine
the angular correlations of these particles with respect to the emission angles
of the evaporation residues. The experimental data are analysed in the
framework of the statistical model. The exclusive energy spectra of
-particles emitted from the Si + Si compound system are
generally well reproduced by Monte Carlo calculations using spin-dependent
level densities. This spin dependence approach suggests the onset of large
deformations at high spin. A re-analysis of previous -particle data
from the Si + Si compound system, using the same spin-dependent
parametrization, is also presented in the framework of a general discussion of
the occurrence of large deformation effects in the A ~ 60 mass region.Comment: 25 pages, 6 figure
Comparisons of Supergranule Characteristics During the Solar Minima of Cycles 22/23 and 23/24
Supergranulation is a component of solar convection that manifests itself on
the photosphere as a cellular network of around 35 Mm across, with a turnover
lifetime of 1-2 days. It is strongly linked to the structure of the magnetic
field. The horizontal, divergent flows within supergranule cells carry local
field lines to the cell boundaries, while the rotational properties of
supergranule upflows may contribute to the restoration of the poloidal field as
part of the dynamo mechanism that controls the solar cycle. The solar minimum
at the transition from cycle 23 to 24 was notable for its low level of activity
and its extended length. It is of interest to study whether the convective
phenomena that influences the solar magnetic field during this time differed in
character to periods of previous minima. This study investigates three
characteristics (velocity components, sizes and lifetimes) of solar
supergranulation. Comparisons of these characteristics are made between the
minima of cycles 22/23 and 23/24 using MDI Doppler data from 1996 and 2008,
respectively. It is found that whereas the lifetimes are equal during both
epochs (around 18 h), the sizes are larger in 1996 (35.9 +/- 0.3 Mm) than in
2008 (35.0 +/- 0.3 Mm), while the dominant horizontal velocity flows are weaker
(139 +/- 1 m/s in 1996; 141 +/- 1 m/s in 2008). Although numerical differences
are seen, they are not conclusive proof of the most recent minimum being
inherently unusual.Comment: 22 pages, 5 figures. Solar Physics, in pres
Living for the weekend: youth identities in northeast England
Consumption and consumerism are now accepted as key contexts for the construction of youth identities in de-industrialized Britain. This article uses empirical evidence from interviews with young people to suggest that claims of `new community' are overstated, traditional forms of friendship are receding, and increasingly atomized and instrumental youth identities are now being culturally constituted and reproduced by the pressures and anxieties created by enforced adaptation to consumer capitalism. Analysis of the data opens up the possibility of a critical rather than a celebratory exploration of the wider theoretical implications of this process
Magazine and reader constructions of 'metrosexuality' and masculinity: a membership categorisation analysis
Since the launch of men's lifestyle magazines in the 1980s, academic literature has predominantly focused on them as a cultural phenomenon arising from entrepreneurial and commercial initiatives and/or as cultural texts that proffer representations of masculinity such as 'new lad' and 'new dad'. This paper steps aside from the focus on culture and, instead, treats magazine content as a discursive space in which gender and sexuality are oriented to, negotiated, and accomplished within and beyond the magazine itself (i.e. through readers' responses). Specifically, membership categorisation analysis is deployed to explore how the relatively new (and perhaps alternative) category for men - 'metrosexual' - is presented and received. Our analysis suggests that masculinity concerns are central in debates about 'metrosexuality', with self-identified 'metrosexuals' invoking heterosexual prowess and self-respect on the one hand, and critics (e.g. selfidentified 'real men') lamenting 'metrosexuality' for its perceived effeminacy and lack of authenticity on the other. Implications for understanding contemporary masculinities are discussed
Spin Glass Behavior in RuSr2Gd1.5Ce0.5Cu2O10
The dynamics of the magnetic properties of polycrystalline
RuSr2Gd1.5Ce0.5Cu2O10 (Ru-1222) have been studied by ac susceptibility and dc
magnetization measurements, including relaxation and ageing studies. Ru-1222 is
a reported magneto-superconductor with Ru spins magnetic ordering at
temperatures near 100 K and superconductivity in Cu-O2 planes below Tc ~ 40 K.
The exact nature of Ru spins magnetic ordering is still debated and no
conclusion has been reached yet. In this work, a frequency-dependent cusp was
observed in ac susceptibility vs. T measurements, which is interpreted as a
spin glass transition. The change in the cusp position with frequency follows
the Vogel-Fulcher law, which is commonly accepted to describe a spin glass with
magnetically interacting clusters. Such interpretation is supported by
themoremanaent magnetization (TRM) measurements at T = 60 K. TRM relaxations
are well described by a stretched exponential relation, and present significant
ageing effects.Comment: 4 pages, 6 figures, submitted to Phys. Rev.
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