68 research outputs found
Afghanistan: neuer alter Präsident vor ungewisser Zukunft
Die Präsidentschaftswahl in Afghanistan hat verdeutlicht, dass Wahlen allein noch kein Ausdruck für eine demokratische Konsolidierung sind. Unregelmäßigkeiten wie etwa präparierte Wahlurnen, "Phantomwähler" und massive Bedrohung von Wahlwilligen, für einen bestimmten Kandidaten zu stimmen, entwerteten das Ergebnis und damit auch jeden auf ihm fußenden Versuch einer Regierungsbildung. Ausländische Regierungen, insbesondere von Staaten, die in Afghanistan Truppen stellen, mussten sich die Frage stellen, wie die Unterstützung einer Regierung mit einer so geringen demokratischen Glaubwürdigkeit zu rechtfertigen ist. Die Absage der Stichwahlen nach dem Rückzug des Zweitplatzierten Abdullah Abdullah und die Ausrufung Hamid Karzais zum Wahlsieger verstärken die Zweifel an der Legitimität seiner Präsidentschaft. (GIGA
Prospects of Open Charm Production at GSI-FAIR and J-PARC
We present a detailed phenomenological study of the prospects of open charm
physics at the future and facilities GSI-FAIR and J-PARC,
respectively. In particular, we concentrate on differential cross sections and
the charge and longitudinal double-spin asymmetries at next-to-leading order
accuracy. Theoretical uncertainties for the proposed observables are estimated
by varying the charm quark mass and the renormalization and factorization
scales.Comment: 11 pages, 13 figure
Electroweak corrections to W-boson pair production at the LHC
Vector-boson pair production ranks among the most important Standard-Model
benchmark processes at the LHC, not only in view of on-going Higgs analyses.
These processes may also help to gain a deeper understanding of the electroweak
interaction in general, and to test the validity of the Standard Model at
highest energies. In this work, the first calculation of the full one-loop
electroweak corrections to on-shell W-boson pair production at hadron colliders
is presented. We discuss the impact of the corrections on the total cross
section as well as on relevant differential distributions. We observe that
corrections due to photon-induced channels can be amazingly large at energies
accessible at the LHC, while radiation of additional massive vector bosons does
not influence the results significantly.Comment: 29 pages, 15 figures, 4 tables; some references and comments on
\gamma\gamma -> WW added; matches version published in JHE
Augmented reality-enhanced navigation in endoscopic sinus surgery: A prospective, randomized, controlled clinical trial
Objective: Endoscopic sinus surgery represents the gold standard for surgical treatment of chronic sinus diseases. Thereby, navigation systems can be of distinct use. In our study, we tested the recently developed KARL STORZ NAV1 SinusTracker navigation software that incorporates elements of augmented reality (AR) to provide a better preoperative planning and guidance during the surgical procedure. Methods: One hundred patients with chronic sinus disease were operated on using either a conventional navigation software (n = 52, non‐AR, control group) or a navigation software incorporating AR elements (n = 48, AR, intervention group). Incidence of postoperative complications, duration of surgery, surgeon‐reported benefit from the navigation system and patient‐reported postoperative rehabilitation were assessed. Results: The surgeons reported a higher benefit during surgery, used the navigation system for more surgical steps and spent longer time with preoperative image analysis when using the AR system as compared with the non‐AR system. No significant differences were seen in terms of postoperative complications, target registration error, operation time and postoperative rehabilitation. Conclusion:
The AR enhanced navigation software shows a high acceptance by sinus surgeons in different stages of surgical training and offers potential benefits during surgery without affecting the duration of the operation or the incidence of postoperative complications
Electroweak-correction effects in gauge-boson pair production at the LHC
We have studied the effect of one-loop logarithmic electroweak radiative
corrections on WZ and production processes at the LHC. We present
analytical results for the leading-logarithmic electroweak corrections to the
corresponding partonic processes du -> WZ, Wgamma. Using the leading-pole
approximation we implement these corrections into Monte Carlo programs for
. We find that electroweak corrections
lower the predictions by 5-20% in the physically interesting region of large
transverse momentum and small rapidity separation of the gauge bosons.Comment: 28 pages, LaTex, 13 eps figures included; references added and
corrected typo
In vivo imaging of pancreatic tumours and liver metastases using 7 Tesla MRI in a murine orthotopic pancreatic cancer model and a liver metastases model
<p>Abstract</p> <p>Background</p> <p>Pancreatic cancer is the fourth leading cause of tumour death in the western world. However, appropriate tumour models are scarce. Here we present a syngeneic murine pancreatic cancer model using 7 Tesla MRI and evaluate its clinical relevance and applicability.</p> <p>Methods</p> <p>6606PDA murine pancreatic cancer cells were orthotopically injected into the pancreatic head. Liver metastases were induced through splenic injection. Animals were analyzed by MRI three and five weeks following injection. Tumours were detected using T2-weighted high resolution sequences. Tumour volumes were determined by callipers and MRI. Liver metastases were analyzed using gadolinium-EOB-DTPA and T1-weighted 3D-Flash sequences. Tumour blood flow was measured using low molecular gadobutrol and high molecular gadolinium-DTPA.</p> <p>Results</p> <p>MRI handling and applicability was similar to human systems, resolution as low as 0.1 mm. After 5 weeks tumour volumes differed significantly (p < 0.01) when comparing calliper measurments (n = 5, mean 1065 mm<sup>3</sup>+/-243 mm<sup>3</sup>) with MRI (mean 918 mm<sup>3</sup>+/-193 mm<sup>3</sup>) with MRI being more precise. Histology (n = 5) confirmed MRI tumour measurements (mean size MRI 38.5 mm<sup>2</sup>+/-22.8 mm<sup>2 </sup>versus 32.6 mm<sup>2</sup>+/-22.6 mm<sup>2 </sup>(histology), p < 0,0004) with differences due to fixation and processing of specimens. After splenic injection all mice developed liver metastases with a mean of 8 metastases and a mean volume of 173.8 mm<sup>3</sup>+/-56.7 mm<sup>3 </sup>after 5 weeks. Lymphnodes were also easily identified. Tumour accumulation of gadobutrol was significantly (p < 0.05) higher than gadolinium-DTPA. All imaging experiments could be done repeatedly to comply with the 3R-principle thus reducing the number of experimental animals.</p> <p>Conclusions</p> <p>This model permits monitoring of tumour growth and metastasis formation in longitudinal non-invasive high-resolution MR studies including using contrast agents comparable to human pancreatic cancer. This multidisciplinary environment enables radiologists, surgeons and physicians to further improve translational research and therapies of pancreatic cancer.</p
Uncertainties and controversies in axillary management of patients with breast cancer
The aims of this Oncoplastic Breast Consortium and European Breast Cancer Research Association of Surgical Trialists initiative were to identify uncertainties and controversies in axillary management of early breast cancer and to recommend appropriate strategies to address them. By use of Delphi methods, 15 questions were prioritized by more than 250 breast surgeons, patient advocates and radiation oncologists from 60 countries. Subsequently, a global virtual consensus panel considered available data, ongoing studies and resource utilization. It agreed that research should no longer be prioritized for standardization of axillary imaging, de-escalation of axillary surgery in node-positive cancer and risk evaluation of modern surgery and radiotherapy. Instead, expert consensus recommendations for clinical practice should be based on current evidence and updated once results from ongoing studies become available. Research on de-escalation of radiotherapy and identification of the most relevant endpoints in axillary management should encompass a meta-analysis to identify knowledge gaps, followed by a Delphi process to prioritize and a consensus conference to refine recommendations for specific trial designs. Finally, treatment of residual nodal disease after surgery was recommended to be assessed in a prospective register
Delphi Initiative for Early-Onset Colorectal Cancer (DIRECt) International Management Guidelines
Background & aims: Patients with early-onset colorectal cancer (eoCRC) are managed according to guidelines that are not age-specific. A multidisciplinary international group (DIRECt), composed of 69 experts, was convened to develop the first evidence-based consensus recommendations for eoCRC. Methods: After reviewing the published literature, a Delphi methodology was used to draft and respond to clinically relevant questions. Each statement underwent 3 rounds of voting and reached a consensus level of agreement of ≥80%. Results: The DIRECt group produced 31 statements in 7 areas of interest: diagnosis, risk factors, genetics, pathology-oncology, endoscopy, therapy, and supportive care. There was strong consensus that all individuals younger than 50 should undergo CRC risk stratification and prompt symptom assessment. All newly diagnosed eoCRC patients should receive germline genetic testing, ideally before surgery. On the basis of current evidence, endoscopic, surgical, and oncologic treatment of eoCRC should not differ from later-onset CRC, except for individuals with pathogenic or likely pathogenic germline variants. The evidence on chemotherapy is not sufficient to recommend changes to established therapeutic protocols. Fertility preservation and sexual health are important to address in eoCRC survivors. The DIRECt group highlighted areas with knowledge gaps that should be prioritized in future research efforts, including age at first screening for the general population, use of fecal immunochemical tests, chemotherapy, endoscopic therapy, and post-treatment surveillance for eoCRC patients. Conclusions: The DIRECt group produced the first consensus recommendations on eoCRC. All statements should be considered together with the accompanying comments and literature reviews. We highlighted areas where research should be prioritized. These guidelines represent a useful tool for clinicians caring for patients with eoCRC
Theory of hard photoproduction
The present theoretical knowledge about photons and hard photoproduction
processes, i.e. the production of jets, light and heavy hadrons, quarkonia, and
prompt photons in photon-photon and photon-hadron collisions, is reviewed.
Virtual and polarized photons and prompt photon production in hadron collisions
are also discussed. The most important leading and next-to-leading order QCD
results are compiled in analytic form. A large variety of numerical predictions
is compared to data from TRISTAN, LEP, and HERA and extended to future electron
and muon colliders. The sources of all relevant results are collected in a rich
bibliography.Comment: Habilitationsschrift, scheduled for publication in Rev. Mod. Phys.,
126 pages, 61 figure
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