45 research outputs found
An efficient renormalization group improved implementation of the MSSM effective potential
In the context of MSSM, a novel improving procedure based on the
renormalization group equation is applied to the effective potential in the
Higgs sector. We focus on the one-loop radiative corrections computed in Landau
gauge by using the mass independent renormalization scheme . Thanks
to the decoupling theorem, the well-known multimass scale problem is
circumvented by switching to a new effective field theory every time a new
particle threshold is encountered. We find that, for any field configuration,
there is a convenient renormalization scale at which the loop
expansion respects the perturbation series hierarchy and the theory retains the
vital property of stability.Comment: 35 pages, 5 figures, RevTe
Unification and fermion mass relations in low string scale D-brane models
In this talk, gauge coupling evolution is analyzed in D-brane inspired models
with two Higgs doublets and a U(3)xU(2)xU(1)^N gauge symmetry. In particular,
we focus on D-brane configurations with two or three abelian factors. We find
that the correct hypercharge assignment of the Standard Model particles is
reproduced for six viable models distinguished by different brane
configurations. We also investigate the bottom tau quark mass relation and find
that the correct low energy m_b / m_\tau ratio is obtained for equal b-\tau
Yukawa couplings at a string scale around 10^3 TeV.Comment: 10 pages, 3 figures. Talk presented at the ``Corfu Summer
Institute'', Corfu-Greece, September 4-14, 2005. To appear in the proceedings
of RTN workshop on the Quest for Unification Theory Confronts Experimen
Anomalous U(1)'s, Chern-Simons couplings and the Standard Model
This proceeding is based on hep-th/0605225 and it shows that the most general
anomaly related effective action contains Stuckelberg, axionic and
Chern-Simons-like couplings. Such couplings are generically non-trivial in
orientifold string vacua. A similar analysis in quantum field theories provides
similar couplings. These Chern-Simons couplings generate new signals which
might be visible at LHC.Comment: 9 pages, 2 eps figures, LaTeX, feynmf & youngtab packages. (v2:
references added). Contribution to the proceedings of the RTN project
"Constituents, Fundamental Forces and Symmetries of the Universe" conference
in Naples, October 9 - 13, 2006 and the PRIN meeting in Alessandria, December
15-16, 200
Operative versus non-operative management of rib fractures in flail chest after cardiopulmonary resuscitation manoeuvres
OBJECTIVES: Blunt chest trauma after mechanical resuscitation manoeuvres appears to have a significant impact on the often complicated course. Due to a lack of data in the literature, the purpose of this study was to investigate the feasibility and immediate outcome of chest wall stabilization for flail chest in this vulnerable patient population. METHODS: We retrospectively reviewed the medical records of patients after cardiopulmonary resuscitation between January 2014 and December 2018 who were diagnosed with flail chest. We attempted to compare patients after surgery with those after conservative treatment. RESULTS: Of a total of 56 patients with blunt chest trauma after mechanical resuscitation and after coronary angiography, 25 were diagnosed with flail chest. After the exclusion of 2 patients because of an initial decision to palliate, 13 patients after surgical stabilization could be compared with 10 patients after conservative therapy. Although there was no significant difference in the total duration of ventilatory support, there was a significant advantage when the time after stabilization to extubation was compared with the duration of ventilation in the conservative group. The presence of pulmonary contusion, poor Glasgow Coma Scale score or the development of pneumonia negatively affected the outcome, but additional sternal fracture did not. CONCLUSIONS: Surgical stabilization for chest wall instability is well tolerated even by this vulnerable patient population. Our results should be used for further randomized controlled approaches. It is necessary to evaluate the situation with all parameters in an interdisciplinary manner and to decide on a possible surgical therapy at an early stage if possible
Surgical smoke: modern mobile smoke evacuation systems improve occupational safety in the operating theatre.
OBJECTIVES
Evaluation of smoke capture efficiency of different mobile smoke evacuation devices with respect to volatile organic compounds and their noise emission.
METHODS
Electrosurgical incisions were performed on fresh porcine liver in an operating room with vertical laminar flow. The generated surgical smoke was analysed with proton-transfer-reaction mass spectrometry with and without the use of a mobile smoke evacuation system consisting of a smoke evacuator machine, a suction hose and a handpiece. The inlet of the mass spectrometer was positioned 40âcm above the specimen. Various devices were compared: a hard plastic funnel, a flexible foam funnel, an on-tip integrated aspirator of an electrosurgical knife and a standard secretion suction (Yankauer). Also, sound levels were measured at a distance of 40âcm from the handpieces' inlet.
RESULTS
The smoke capture efficiency of the secretion suction was only 53%, while foam funnel, plastic funnel and integrated aspirator were all significantly more effective with a clearance of 95%, 91% and 91%, respectively. The mean sound levels were 68 and 59 A-weighted decibels with the plastic and foam funnel, respectively, 66 A-weighted decibels with the integrated aspirator and 63 A-weighted decibels with the secretion suction.
CONCLUSIONS
Carcinogenic, mutagenic and reprotoxic volatile organic compounds in surgical smoke can be efficiently reduced by mobile smoke evacuation system, providing improved protection for medical personnel. Devices specifically designed for smoke evacuation are more efficient than standard suction tools. Noise exposure for the surgeon was lowest with the flexible foam funnel and higher with the other handpieces tested
Randomized Controlled Trial of Thresholds for Drain Removal After Anatomic Lung Resection.
BACKGROUND
The criteria for chest drain removal following lung resections remain vague and rely on personal experience instead of evidence. Since pleural fluid resorption is proportional to body weight, a weight-related approach seems reasonable. We examined the feasibility of a weight-adjusted fluid output threshold concerning postoperative respiratory complications and the occurrence of symptomatic pleural effusion after chest drain removal. Our secondary objectives were the length of hospital stay and the pain levels before and after chest drain removal.
METHODS
Single-center randomized controlled trial including 337 patients planned for open or thoracoscopic anatomical lung resections. Patients were randomized postoperatively into two groups. The chest drain was removed in the study group according to a fluid output threshold calculated by the 5 mL x body weight (in kg) / 24 hours formula. In the control group, our previous traditional fluid threshold of 200 mL/ 24 hours was applied.
RESULTS
No differences were evident regarding the occurrence of pleural effusion, dyspnea at discharge and 30 days postoperatively. In the logistic regression analysis, the surgical modality was a risk factor for other complications, and age was the only variable influencing postoperative dyspnea. Time to chest drain removal was identical in both groups, and time to discharge was shorter following open surgery in the test group.
CONCLUSIONS
No increased postoperative complications occurred with this weight-based formula, and a trend toward earlier discharge after open surgery was observed in the test group
Landscape of Little Hierarchy
We investigate the little hierarchy between Z boson mass and the SUSY
breaking scale in the context of landscape of electroweak symmetry breaking
vacua. We consider the radiative symmetry breaking and found that the scale
where the electroweak symmetry breaking conditions are satisfied and the
average stop mass scale is preferred to be very close to each other in spite of
the fact that their origins depend on different parameters of the model. If the
electroweak symmetry breaking scale is fixed at about 1 TeV by the
supersymmetry model parameters then the little hierarchy seems to be preferred
among the electroweak symmetry breaking vacua. We characterize the little
hierarchy by a probability function and the mSUGRA model is used as an example
to show the 90% and 95% probability contours in the experimentally allowed
region. We also investigate the size of the Higgsino mass by considering the
distribution of electroweak symmetry breaking scale.Comment: 19 pages, 4 figure
Two-loop corrections to Radiative Electroweak Symmetry Breaking in the MSSM
We study the O(at*as + at^2) two-loop corrections to the minimization
conditions of the MSSM effective potential, providing compact analytical
formulae for the Higgs tadpoles. We connect these results with the
renormalization group running of the MSSM parameters from the grand unification
scale down to the weak scale, and discuss the corrections to the Higgs mixing
parameter mu and to the running CP-odd Higgs mass mA in various scenarios of
gravity-mediated SUSY breaking. We find that the O(at*as) and O(at^2)
contributions partially cancel each other in the minimization conditions. In
comparison with the full one-loop corrections, the O(at*as + at^2) two-loop
corrections significantly weaken the dependence of the parameters mu and mA on
the renormalization scale at which the effective potential is minimized. The
residual two-loop and higher-order corrections to mu and mA are estimated to be
at most 1% in the considered scenarios.Comment: 23 pages, 7 figures. Version to appear in Nucl. Phys.