362 research outputs found
Adiabatic Floquet model for the optical response in femtosecond filaments
The standard model of femtosecond filamentation is based on phenomenological
assumptions which suggest that the ionization-induced carriers can be treated
as free according to the Drude model, while the nonlinear response of the bound
carriers follows the all-optical Kerr effect. Here, we demonstrate that the
additional plasma generated at a multiphoton resonance dominates the saturation
of the nonlinear refractive index. Since resonances are not captured by the
standard model, we propose a modification of the latter in which ionization
enhancements can be accounted for by an ionization rate obtained from
non-Hermitian Floquet theory. In the adiabatic regime of long pulse envelopes,
this augmented standard model is in excellent agreement with direct quantum
mechanical simulations. Since our proposal maintains the structure of the
standard model, it can be easily incorporated into existing codes of filament
simulation.Comment: 14 pages, 6 figures, submitted to New Journal of Physic
Femtosecond filamentation by intensity clamping at a Freeman resonance
We demonstrate that Freeman resonances have a strong impact on the nonlinear
optical response in femtosecond filaments. These resonances decrease the
transient refractive index within a narrow intensity window and strongly affect
the filamentation dynamics. In particular, we demonstrate that the peak
intensity of the filament can be clamped at these resonances, hinting at the
existence of new regimes of filamentation with electron densities considerably
lower than predicted by the standard model. This sheds a new light on the
phenomenon of filamentary intensity clamping and the plasmaless filaments
predicted by the controversial higher-order Kerr model
EU-Osterweiterung und Zuwanderung nach Sachsen
Für Sachsen wurde erstmalig explizit das Migrations- und Pendlerpotenzial aus den acht mittel- und osteuropäischen Beitrittsländern der nächsten EU-Erweiterungsrunde geschätzt. Bei sofortiger Herstellung der Arbeitnehmerfreizügigkeit ergäbe sich für den Freistaat ein Potenzial von 65.000 bis 85.000 Zuwanderern, zuzüglich etwa 30.000 Pendlern. Aufgrund des bevorstehenden Rückgangs der erwerbsfähigen Bevölkerung und dem sich abzeichnenden Mangel an qualifiziertem Nachwuchs, sollten die Grenzen für die Hochqualifizierten frühzeitig geöffnet werden.Internationale Arbeitsmobilität; Ausländische Arbeitskräfte; Einwanderung; EU-Erweiterung; Sachsen
Der Maschinenbau im Zeitalter der Globalisierung und "New Economy"
Die Studie "Der Maschinenbau im Zeitalter der Globalisierung und New Economy" wurde vom ifo Institut in Zusammenarbeit mit dem Frauenhofer Institut für System- und Innovationsforschung erstellt. Gegenstand der Studie ist die Entwicklung des deutschen Maschinenbaus mit den Veränderungen durch die vertiefende internationale Arbeitsteilung und die zunehmende Diffusion von Informations- und Kommunikationstechnologien. Die Ergebnisse sollen dazu beitragen, die Perspektiven dieser aufgrund ihrer hohen internationalen Wettbewerbsfähigkeit für die deutsche Wirtschaft wichtigen Branche zu verbessern
TOT Approach in stress urinary incontinence (SUI) – outcome in obese female
BACKGROUND: Only limited data are available on the outcome of tension-free obturator tape (TOT) procedures in overweight and obese women. We would like to verify the objective and subjective outcomes of TOT in women with a higher body mass index (BMI). METHODS: We evaluated the records of 116 patients who had undergone TOT, stratifying by BMI into normal weight (n = 31), overweight (n = 56), and obese (n = 29) groups. We compared pre- and postoperative evaluations, including subjective and objective outcome of TOT, complications, and quality of life assessed by validated questionnaires (ICIQ-SF and KHQ). RESULTS: The median follow-up was 21 months. There were no significant differences between different groups in terms of objective cure rate and subjective success, quality of life scores and postoperative complications. CONCLUSIONS: Our data demonstrate that TOT procedure is safe and effective. BMI did not influence the outcome of TOT procedures at a median of 21 months after surgery and represents no contraindication for continence surgery. The success of the outcome of TOT procedure in females and the occurrence of complications are not negatively affected by obesity
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Continuous Wave THz System Based on an Electrically Tunable Monolithic Dual Wavelength Y-Branch DBR Diode Laser
We analyse the use of a tunable dual wavelength Y-branch DBR laser diode for THz applications. The laser generates electrically tunable THz difference frequencies in the range between 100 and 300 GHz. The optical beats are tuned via current injection into a micro-resistor heater integrated on top of one of the distributed Bragg reflector (DBR) section of the diode. The laser is integrated in a homodyne THz system employing fiber coupled ion-implanted LT-GaAs log spiral antennas. The applicability of the developed system in THz spectroscopy is demonstrated by evaluating the spectral resonances of a THz filter as well as in THz metrology in thickness determination of a polyethylene sample
A retrospective case–control study for the comparison of 5-year survival rates: the role of adjuvant and neoadjuvant chemotherapy in craniofacial bone sarcoma in adults
Background: The impact of adjuvant or neoadjuvant chemotherapy in the treatment of craniofacial bone sarcomas has not been clarified. This study aimed to assess whether survival outcomes differed between patients who underwent adjuvant or neoadjuvant chemotherapy.
Methods: A retrospective search for adult patients diagnosed with malignant neoplasms of the craniofacial bones (International Classification of Diseases 10 codes C41.0-C41.1), within the past 20 years from the access date 28 April 2022, was conducted using the TriNetX network (TriNetX, Cambridge, MA, USA). Cohort I included patients who underwent adjuvant chemotherapy and cohort II included patients with neoadjuvant chemotherapy. A refined search for individuals that received common chemotherapeutic agents, such as methotrexate, doxorubicin, cisplatin, and/or ifosfamide, was conducted and patients were assigned to cohort A (adjuvant chemotherapy) and cohort B (neoadjuvant chemotherapy). Following matching for age and sex, Kaplan-Meier analysis was performed, and risk ratio, odds ratio (OR), and hazard ratio were calculated.
Results: Patients were assigned to two cohorts, with 181 patients each after matching. In cohorts I and II, 55 and 41 patients died, respectively. No significant differences were found between the two cohorts regarding the 5-year survival probability (I: 59.87% versus II: 68.45%; p = 0.076; log-rank test), or the risk of dying (I: 0.304 versus II: 0.227; risk difference: 0.077; p = 0.096). The risk analysis before matching for age and sex showed a significant survival benefit in cohort II (OR: 1.586; p = 0.0295; risk difference: 0.093). After a refined query to identify patients treated with methotrexate, doxorubicin, cisplatin, and/or ifosfamide, the two cohorts included 47 patients, respectively. In cohort A (adjuvant chemotherapy), 19 patients died, whereas 12 patients died in cohort B (neoadjuvant chemotherapy) within 5 years after diagnosis. Further analysis indicated a greater survival in cohort B, but the survival probability between the cohorts did not differ significantly (A: 43.55% versus B: 54.49%; p = 0.171).
Conclusion: The use of neoadjuvant chemotherapy may improve survival rates in patients with surgically treated craniofacial bone sarcomas. Due to the retrospective nature of this study, randomized controlled studies are required to derive treatment recommendations
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