1,460 research outputs found
The Role of Popliteal Vein Incompetence in the Diagnosis of Saphenous-popliteal Reflux Using Continuous Wave Doppler
AbstractIntroduction: continuous wave Doppler (CWD) has good discriminatory power at the groin in the assessment of saphenous femoral junction (SFJ); however, it is not as accurate as duplex ultrasound scanning (DUS) in the popliteal fossa for assessment of saphenous popliteal junction (SPJ) in patients with primary short saphenous vein incompetence.Aim: the aim of this study was to compare the findings of CWD with those of DUS at the SPJ and assess the role of popliteal vein incompetence in the accuracy of CWD. Method: prospective study of consecutive patients presenting to a vein clinic requiring a duplex scan of their SPJ. Each patient was examined by one surgeon using CWD and by one radiologist using DUS. Each observer was unaware of the other's findings. Additional information on the competence of the popliteal vein on DUS was also recorded. Results: some 171 limbs in 128 patients with varicose veins were studied. One hundred and sixteen limbs had reflux at SPJ on CWD whilst 55 did not. Their mean age was 54 (range 18–85). Female to male ratio was 3:1. Spearman's rank correlation between CWD and DUS has 0.49 (p =0.0001). CWD has a sensitivity of 92% and specificity of 53% (PPV=62%, NPV=89%, accuracy=70%). Twenty-nine limbs had an incompetent popliteal vein (IPV). Of those, 12 limbs also had incompetence on CWD and competence on DUS at the SPJ, which represent 28% of the total number of limbs with these findings (n =43). Conclusion: CWD is sensitive in detecting incompetence at SPJ, though its specificity is low. In this study 17% (n =29) of all patients had incompetence of popliteal vein. Up to 25% ( n =12) of patients with SPJ incompetence on CWD (Doppler +) and competence on DUS (duplex −) had incompetence of the underlying popliteal vein, which may explain the low specificity. The presence of SPJ incompetence on CWD should be confirmed on DUS prior to surgery
Simulação Em 3d Da Redução Da Fossa Posterior No Chiari Do Tipo I
We proposed a 3D model to evaluate the role of platybasia and clivus length in the development of Chiari I (CI). Using a computer aided design software, two DICOM files of a normal CT scan and MR were used to simulate different clivus lengths (CL) and also different basal angles (BA). The final posterior fossa volume (PFV) was obtained for each variation and the percentage of the volumetric change was acquired with the same method. The initial normal values of CL and BA were 35.65 mm and 112.66° respectively, with a total PFV of 209 ml. Ranging the CL from 34.65 to 29.65-24.65-19.65, there was a PFV decrease of 0.47%-1.12%-1.69%, respectively. Ranging the BA from 122.66° to 127.66°-142.66°, the PFV decreased 0.69%-3.23%, respectively. Our model highlights the importance of the basal angle and clivus length to the development of CI. © 2016, Associacao Arquivos de Neuro-Psiquiatria. All rights reserved.74540540
Anomalous persistent photoconductivity in Cu2ZnSnS4 thin films and solar cells
A persistent photoconductivity effect (PPC) has been investigated in Cu2ZnSnS4 thin films and solar cells as a function of temperature. An anomalous increase of the PPC decay time with temperature was observed in all samples. The PPC decay time activation energy was found to increase when temperature rises above a crossover value, and also to grow with the increase of the sulfurization temperature and pressure. Both the anomalous behavior of the PPC decay time and the existence of two different activation energies are explained in terms of local potential fluctuations in the band edges of CZTS
The Thirring interaction in the two-dimensional axial-current-pseudoscalar derivative coupling model
The authors reexamine the two-dimensional model of massive fermions
interacting with a massless pseudoscalar field via axial-current-pseudoscalar
derivative coupling. Performing a canonical field transformation on the Bose
field algebra the model is mapped into the Thirring model with an additional
vector-current-scalar-derivative interaction (Schroer-Thirring model). The
complete bosonized version of the model is presented. The bosonized composite
operators of the quantum Hamiltonian are obtained as the leading operators in
the Wilson short distance expansion.Comment: 13 page
Significance Of Assessment Experiences During Initial Teacher Training In Physical Education
This study investigates how students in the final semester of their teacher training program (licensure) at the Center of Physical Education and Sports (CEFD), EspÃrito Santo Federal University, Brazil, (re)interpret their assessment experiences, an integral component of their teacher training. It employs the narrative as a theoretical and methodological perspective, and it utilizes student portfolios, as well as focus groups and semi-structured individual interviews as inputs for data generation. Ten students in their eighth, or final, semester participated in this study. These were the total respondents to a "call for volunteers" among the 2014 graduating class. The results suggest that the students believe the assessment processes of their teaching practices in physical education are disjointed. They feel that the disciplines that allow them to review their own performance during teacher training are more efficient and play a stronger role in their education.221627
On the consistency of the three-dimensional noncommutative supersymmetric Yang-Mills theory
We study the one-loop quantum corrections to the U(N) noncommutative
supersymmetric Yang-Mills theory in three spacetime dimensions (NCSYM). We
show that the cancellation of the dangerous UV/IR infrared divergences only
takes place in the fundamental representation of the gauge group. Furthermore,
in the one-loop approximation, the would be subleading UV and UV/IR infrared
divergences are shown to vanish.Comment: 8 pages and 2 figure
Supersymmetric non-Abelian noncommutative Chern-Simons theory
In this work, we study the three-dimensional non-Abelian noncommutative
supersymmetric Chern-Simons model with the U(N) gauge group. Using a superfield
formulation, we prove that, for the pure gauge theory, the Green functions are
one-loop finite in any gauge, if the gauge superpotential belongs to the
fundamental representation of ; this result also holds when matter in the
fundamental representation is included. However, the cancellation of both
ultraviolet and ultraviolet/infrared infrared divergences only happens in a
special gauge if the coupling of the matter is in the adjoint representation.
We also look into the finite one-loop quantum corrections to the effective
action: in the pure gauge sector the Maxwell together with its corresponding
gauge fixing action are generated; in the matter sector, the Chern-Simons term
is generated, inducing a shift in the classical Chern-Simons coefficient.Comment: 16 pages, 3 figures, revtex4, enhanced discussion, mainly of the
finite part of quantum corrections, and the shift in the Chern-Simons
coefficien
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