10,372 research outputs found
Mitosis: New Roles for Myosin-X and Actin at the Spindle
SummaryRoles for actin and myosin in positioning mitotic spindles in the cell are well established. A recent study of myosin-X function in early Xenopus embryo mitosis now reports that this unconventional myosin is required for pole integrity and normal spindle length by localizing to poles and exerting pulling forces on actin filaments within the spindle
NLO corrections to differential cross sections for pseudo-scalar Higgs boson production
We have computed the full next-to-leading (NLO) QCD corrections to the
differential distributions for pseudo-scalar Higgs (A)
production at large hadron colliders. This calculation has been carried out
using the effective Lagrangian approach which is valid as long as the mass of
the pseudo-scalar Higgs boson and its transverse momentum do
not exceed the top-quark mass . The shape of the distributions hardly
differ from those obtained for scalar Higgs (H) production because, apart from
the overall coupling constant and mass, there are only small differences
between the partonic differential distributions for scalar and pseudo-scalar
production. Therefore there are only differences in the magnitudes of the
hadronic differential distributions which can be mainly attributed to the
unknown mixing angle describing the pseudo-scalar Higgs coupling to the
top quarks.Comment: 9 pages, LaTeX, 3 Postscript figures In the previous version we have
forgotten to include contributions which arrise from interferences between
graphs containing vertices corresponding to the operator in Eq. (3)
with graphs originating from the operator . These interferences occur
because of the prescription for the Levi-Civita tensor given in our paper.
These extra contributions are added to Eqs. (19) and (20). Numerically they
are completely negligible so that the figures are not altere
A QCD Calculation of the Interaction of Quarkonium with Nuclei
The interaction of quarkonium with nuclei is studied in the limit of QCD, where the binding energy is found to be exactly
computable. The dominant contribution to the interaction is from two-gluon
operators. The forward matrix elements of these two-gluon operators can be
determined from the QCD scale anomaly, and from deep inelastic scattering. We
apply our results to the and , treating the \qqbar
interaction as purely Coulombic. We find the binds in nuclear matter
with a binding energy of a few \mev, while for the binding is of
order 10 \mev. For the in particular we expect confinement effects
to produce large corrections to this result.Comment: (10 pages
The Vector Population Monitoring Tool (VPMT): High-Throughput DNA-Based Diagnostics for the Monitoring of Mosquito Vector Populations
Regular monitoring of mosquito vector populations is an integral component of most vector control programmes. Contemporary data on mosquito species composition, infection status, and resistance to insecticides are a prerequisite for effective intervention. For this purpose we, with funding from the Innovative Vector Control Consortium (IVCC), have developed a suite of high-throughput assays based on a single “closed-tube” platform that collectively comprise the “Vector Population Monitoring Tool” (VPMT). The VPMT can be used to screen mosquito disease vector populations for a number of traits including Anopheles gambiae s.l. and Anopheles funestus species identification, detection of infection with Plasmodium parasites, and identification of insecticide resistance mechanisms. In this paper we focus on the Anopheles-specific assays that comprise the VPMT and include details of a new assay for resistance todieldrin Rdl detection. The application of these tools, general and specific guidelines on their use based on field testing in Africa, and plans for further development are discussed
Inelastic J/psi and Upsilon hadroproduction
We consider the prompt hadroproduction of J/psi, psi' and the Upsilon
(1S,2S,3S) states caused by the fusion of a symmetric colour-octet two-gluon
state and an additional gluon. The cross sections are calculated in
leading-order perturbative QCD. We find a considerable enhancement in
comparison with previous perturbative QCD predictions. Indeed, the resulting
cross sections are found to be consistent with the values measured at the
Tevatron and RHIC, without the need to invoke non-perturbative `colour-octet'
type of contributions.Comment: 21 pages, 10 figures; several clarifying sentences and an additional
reference have been adde
Next-to-leading Log Resummation of Scalar and Pseudoscalar Higgs Boson Differential Cross-Sections at the LHC and Tevatron
The region of small transverse momentum in q qbar- and gg-initiated processes
must be studied in the framework of resummation to account for the large,
logarithmically-enhanced contributions to physical observables. In this paper,
we will calculate the fixed order next-to-leading order (NLO) perturbative
total and differential cross-sections for both a Standard Model (SM) scalar
Higgs boson and the Minimal Supersymmetric Standard Model's (MSSM) pseudoscalar
Higgs boson in the Heavy Quark Effective Theory (HQET) where the mass of the
top quark is taken to be infinite. Resummation coefficients B^2_g, C^2_gg for
the total cross-section resummation for the pseudoscalar case are given, as
well as C^1_gg for the differential cross-section.Comment: 18 pages, REVTeX4, 5 eps figures. v2: Typos corrected, references
added, a discussion of uncertainties was adde
Teamwork training in sport:A pilot intervention study
The purpose of this study was to test the efficacy of a novel team building intervention that targets teamwork in sport. Using a 10-week pilot nonrandomized controlled intervention design, 12 interdependent sports teams comprising 187 athletes were assigned to one of two conditions: an experimental condition in which teams participated in two teamwork training sessions at Weeks 2 and 6 of the study (6 teams, 94 athletes) or a no-training control condition (6 teams, 93 athletes). Teamwork was measured at Weeks 1, 5, and 10 of the study. Overall, significant improvements in teamwork were shown for the experimental teams from baseline to Week 5; these effects were maintained through Week 10 of the study. In contrast, no significant changes in teamwork were observed for teams in the control condition over these 10 weeks. The results provide evidence that teamwork training can enhance the extent to which members of a sports team work effectively together
Re‐defining the virtual reality dental simulator: Demonstrating concurrent validity of clinically relevant assessment and feedback
Introduction
Virtual reality (VR) dental simulators are gaining momentum as a useful tool to educate dental students. To date, no VR dental simulator exercise has been designed which is capable of reliably providing validated, meaningful clinical feedback to dental students. This study aims to measure the concurrent validity of the assessment, and the provision of qualitative feedback, pertaining to cavity preparations by VR dental simulators.
Methods
A cavity preparation exercise was created on a VR dental simulator, and assessment criteria for cavity preparations were developed. The exercise was performed 10 times in order to demonstrate a range of performances and for each, the simulator feedback was recorded. The exercises were subsequently three‐dimensionally printed and 12 clinical teachers were asked to assess the preparations according to the same criteria. Inter‐rater reliability (IRR) between clinical teachers was measured using a free‐marginal multirater kappa value. Clinical teacher assessment responses were compared with the VR simulator responses and percentage agreements calculated.
Results
IRR values for each exercise ranged from 0.39‐0.77 (69.39‐88.48%). The assessment of smoothness (κfree0.58, 78.79%) and ability to follow the outline (κfree0.56, 77.88%) demonstrated highest agreement between clinical teachers, whilst the assessment of undercut (κfree0.15, 57.58%) and depth (κfree 0.28, 64.09%) had the lowest agreement. The modal percentage agreement between clinical teachers and the VR simulator was, on average, 78% across all exercises.
Conclusion
The results of this study demonstrate that it is possible to provide reliable and clinically relevant qualitative feedback via a VR dental simulator. Further research should look to employ this technique across a broader range of exercises that help to develop other complex operative dental skills
Chemsex, Anxiety and Depression Among Gay, Bisexual and Other Men Who have Sex with Men Living with HIV
Funding Research did not receive any specific funding.Peer reviewedPublisher PD
The impact of tensioning device mal-positioning on strand tension during Anterior Cruciate Ligament reconstruction
<p>Abstract</p> <p>Background</p> <p>In order to confer optimal strength and stiffness to the graft in Anterior Cruciate Ligament (ACL) reconstruction, the maintenance of equal strand tension prior to fixation, is desired; positioning of the tensioning device can significantly affect strand tension This study aimed to determine the effect of tensioning device mal-positioning on individual strand tension in simulated cadaveric ACL reconstructions.</p> <p>Methods</p> <p>Twenty cadaveric specimens, comprising bovine tibia and tendon harvested from sheep, were used to simulate ACL reconstruction with a looped four-strand tendon graft. A proprietary tensioning device was used to tension the graft during tibial component fixation with graft tension recorded using load cells. The effects of the tensioning device at extreme angles, and in various locking states, was evaluated.</p> <p>Results</p> <p>Strand tension varied significantly when the tensioning device was held at extreme angles (p < 0.001) or in 'locked' configurations of the tensioning device (p < 0.046). Tendon position also produced significant effects (p < 0.016) on the resultant strand tension.</p> <p>Conclusion</p> <p>An even distribution of tension among individual graft strands is obtained by maintaining the tensioning device in an unlocked state, aligned with the longitudinal axis of the tibial tunnel. If the maintenance of equal strand tension during tibial fixation of grafts is important, close attention must be paid to positioning of the tensioning device in order to optimize the resultant graft tension and, by implication, the strength and stiffness of the graft and ultimately, surgical outcome.</p
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