Experimental and numerical study of interlock requirements for high-power EYDFAs.

In this work, we studied the interlock requirements in a seed failure scenario for Er3+:Yb3+ doped fiber amplifiers (EYDFAs) pumped with high intensities in the MWcm-2 range at 9XX nm. We fed a time-dependent FEM-tool with the data from backwards directed amplified spontaneous emission (ASE) transients of different commercially available core-pumped single-mode fibers. In the FEM-tool, the Er3+:Yb3+ system is defined as a bi-directional energy transfer process and described by the corresponding rate equations. The power evolution of the pump, seed, and ASE signal is computed by differential equations taking into account the transient population densities of the relevant energy levels. With the model, we computed the temporal evolution of the corresponding energy levels after a seeder failure to take place within tens to hundreds of µs and calculated the associated gain. The fibers under test provide a critical total gain of 30 dB after ∼ 80 µs within the Yb3+ band and after ∼300 µs within the Er3+ band. This time decreases with increasing pump power and doping concentration. The results can be extrapolated to high-power cladding-pumped EYDFAs to meet the challenging requirements of engineering-level systems.

An examination of advanced practice nurses' job satisfaction internationally.

AIM: To examine the level of job satisfaction of nurse practitioners/advanced practice nurses in developing and developed countries. BACKGROUND: The nurse practitioner/advanced practice nurse has the advanced, complex skills and experience to play an important role in providing equitable health care across all nations. INTRODUCTION: Key factors that contribute to health disparities include lack of access to global health human resources, the right skill mix of healthcare providers and the satisfaction and retention of quality workers. METHODS: The study utilized a descriptive analysis and cross-sectional survey methodology with quantitative and qualitative sections of 1419 job satisfaction survey respondents from an online survey. RESULTS: Age, number of hours worked in a week and length of time that nurse practitioners/advanced practice nurses worked in their current jobs were statistically significant in job satisfaction. A key barrier was the lack of respect from supervisors and physicians. DISCUSSION: It was clear from the number of comments in the qualitative section of the survey that having a wide scope of practice is rewarding and challenging to the nurse practitioner and advanced practice nurse. CONCLUSION AND IMPLICATIONS FOR HEALTH POLICY: The challenges to transform healthcare gaps of access into a better distribution of health care in all countries would constitute a systematic change in policy including providing education and training for doctors and nurses that will match the skills needed in the workplace; emphasizing the right skill mix for the healthcare team; supporting advanced practice nurses in the workplace; and utilizing all healthcare providers to the fullest extent of their abilities.

Gain dynamics in Er(3+):Yb(+) co-doped fiber amplifiers.

Understanding the gain dynamics of fiber amplifiers is essential for the implementation and active stabilization of low noise amplifiers or for coherent beam combining schemes. The gain dynamics of purely Er3+ or Yb3+ doped fiber amplifiers are well studied, whereas no analysis for co-doped systems, especially for Er3+:Yb3+ co-doped fiber amplifiers has been performed, so far. Here, we analyze for the first time the gain dynamics of Er3+:Yb3+ co-doped fiber amplifiers theoretically and experimentally. It is shown that due to the energy transfer between the Yb3+ and Er3+ ions a full analytical solution is not possible. Thus, we used numerical simulations to gain further insights. Comparison of experimental and numerical results shows good qualitative agreement. In addition, we were able to determine the Yb3+-Er3+ transfer function of the energy transfer experimentally.

Gain dynamics in Raman fiber lasers and passive pump-to-Stokes RIN suppression.

We report on theoretical and experimental investigations of gain dynamics in Raman fiber lasers in the frequency range of 1 Hz-1 MHz. An analytical solution of the problem is due to the nonlinear nature of the Raman effect not feasible. Thus, we used a numerical simulation to gain general insights. Experimentally and numerically obtained results for a Raman fiber laser emitting at 1180 nm show good qualitative agreement. We also present a potential physical interpretation of the observed dynamical properties. In addition, we report on an experimental proof-of-principle of a passive pump-to-Stokes RIN suppression scheme for the main Stokes order in cascaded Raman fiber lasers utilizing an additional parasitic Stokes order. Again, results from numerical and experimental studies of a cascaded Raman fiber laser at 1180 nm and 1240 nm show good agreement and confirm the passive pump-to-Stokes RIN suppression at 1180 nm. The dependencies between the resonator design and the parameters of the noise suppression are investigated. In addition, it is shown that the scheme can also be applied to cascaded Raman fiber lasers with more then two Stokes shifts. This opens the possibility to design for example low-noise Raman fiber lasers at 1480 nm to pump low-noise Er(3+) doped fiber amplifiers.

Co-seeded Er3+:Yb3+ single frequency fiber amplifier with 60 W output power and over 90% TEM(00) content.

We report on the design and fabrication of an Er(3+):Yb(3+) triple clad fiber and on the power scaling of a single frequency fiber amplifier at 1.5 µm based on that fiber. In addition, we report on mode content measurements in order to reveal the overlap of the amplifier output with the TEM(00) mode. The triple clad design was used to enable high output power levels, a good slope efficiency and an excellent beam quality. A maximum single frequency output power of 61 W at 1.5 µm could be achieved with the aid of the co-seeding method, which was used to suppress parasitic processes at 1.0 µm. With a scanning ring cavity the mode content of the amplifier output was analyzed with respect to the TEM modes. For all output power levels the TEM(00) content was above 90%.

[Biomedicine in thoracic surgery: state of the art]. / Biomedizin in der Thoraxchirurgie: eine Standortbestimmung.

Biomedicine represents a new scientific field at the interface of human, molecular and cell biology and medicine. Comprising the diverse disciplines of stem cell research, tissue engineering and material sciences, biomedicine gives rise to new approaches in research and therapy for - to date - unmet medical issues. Biomedical research is currently conducted in many medical, especially surgical subspecialties, and a number of successful developments have already been brought to clinical application. Concerning thoracic surgery, biomedical approaches are pursued primarily for tissue and organ replacement of the upper airways, lung and thoracic wall. In spite of a comparatively small research foundation, five different concepts have been clinically implemented worldwide, due to a lack of established treatment options in the case of extensive disease of the greater airways. In this review, the clinical background and the tissue-specific basics of tracheobronchial biomedicine are presented.

Full-scale experiences of nitrogen removal of fish-processing wastewater with flotation and anoxic-aerobic activated sludge system.

This article presents full scale experience of one of the largest fish-processing factories in Europe with a production capacity of about 50,000 tons herring per year and a maximum daily wastewater discharge of 1,500 m(3). The wastewater treatment plant is the only direct discharger in the fish-processing industry in Germany. Thus, very low effluent values have to be keep in, especially the nitrogen reduction has to be operated during the whole year even when the temperature is low. The central point of the multi-stage WWTP (about 90,000 PE) is the biological nutrient removal (BNR) with pre-denitrification. The wastewater pre-treatment with sieves (0.8 mm) and a two staged flotation reduces the nitrogen load - mainly the particle bounded fraction - but the optimal nutrient ratios for biological treatment need to be observed. The activated sludge system has maximum OLR of 0.12 g COD/(g MLSS d) and NLR of 0.015 g TN/(g MLSS d) but a "Stand-By"-Operation with periods without wastewater influent is unavoidable. Discontinuous operating is one problem. The dependence on temperature as one of the main influences of nitrification-activity is the second point. The article gives an overview about the start-up and the optimisation of the process.

Technological approaches to in-room CBCT imaging.

The use of Cone-Beam Computed Tomography (CBCT) in Image-Guided Radiation Therapy (IGRT) has become increasingly feasible and popular in recent years. Advances and developments in Flat-Panel Imager (FPI) technology and image reconstruction software allow for linac-mounted 3D CBCT imaging. Taking CBCT images on a daily/weekly basis, offers the possibility to guide the treatment beam according to tumour motion and to apply changes to the treatment plan if necessary. This however raises the issue of additional imaging dose and thus increases in secondary cancer risk. The performance characteristics of kV-CBCT and MV-CBCT solutions currently offered by Elekta, Siemens and Varian are compared in this paper in terms of additional imaging dose and image quality. The review also outlines applications of CBCT for IGRT and Adaptive Radiotherapy (ART). As CBCT is not the only in-room IGRT platform, helical MV-CT (Tomotherapy) and in-room CT designs are also presented.

Search for the rare decay B-->pil+ l-.

We have performed a search for the flavor-changing neutral-current decays B-->pil+ l-, where l+ l- is either e+ e- or mu+ mu-, using a sample of 230 x 10(6) Upsilon(4S)-->BB decays collected with the BABAR detector. We observe no evidence of a signal and measure the upper limit on the isospin-averaged branching fraction to be B(B-->pil+ l-)<9.1 x 10(-8) at 90% confidence level. We also search for the lepton-flavor-violating decays B-->pie+/- mu-/+ and measure an upper limit on the isospin-averaged branching fraction of B(B-->pie+/- mu-/+)<9.2 x 10(-8) at 90% confidence level.

Hohmann-Thomasen metatarsal osteotomy for tailor's bunion (bunionette).

We used subcapital displacement osteotomy of the fifth metatarsal bone and peg-and-hole fixation to treat a tailor's bunion (bunionette) in forty-four feet (twenty-seven patients). The result was good in 86 per cent, fair in 9 per cent, and poor in 5 per cent. All but one of the patients were satisfied with the result. The average medial displacement of the head of the fifth metatarsal was five millimeters. In all feet, secure union was noted in five weeks, and no patient had osteonecrosis of the head of the fifth metatarsal.

A comparative analysis of burn injuries at two burns centres in Denmark.

In order to compare the epidemiology of burns and predisposing factors to burns at two burn centres representing the cities of Aarhus and Copenhagen, Denmark, a prospective study was set up at the University Department of Orthopedic Surgery and Traumatology, Aarhus and the Centre of Plastic Surgery and Burns Unit, Hvidovre Hospital, Denmark. Several significant differences in the epidemiology of burns in the two populations were found. Considering the social circumstances, the situation in Aarhus was characterized by the fact that most patients lived in their own houses, had a larger family and a larger family income. At the Hvidovre Hospital, the patients more often lived in a flat, had a smaller family and a lower family income than the average.

Separation of tendon ends after Achilles tendon repair: a prospective, randomized, multicenter study.

Fifty-seven patients treated for an acute rupture of the Achilles tendon were studied. The patients were randomized into a Mason suture technique or a reinforced continuous six-strand suture technique, and markers were attached to each tendon end perioperatively. The postoperative separation of the markers was studied by repeat radiographic examination. Despite immobilization, separation developed after a biphasic course, and after 7 weeks the mean separation was 10.5 mm. No difference was found between the two techniques. We attempt to correlate the separation to the clinical outcome, examined at 1 year follow up.

Slipped capital femoral epiphysis: long-term results of an abandoned technique.

Sixty-two (11 women and 51 men) of 76 consecutive patients treated between January 1960 and December 1979 with percutaneous pinning, traction, and ambulation in Thomas splints for slipped capital femoral epiphyses (physiolysis colli femoris; PCF) were re-examined radiologically and clinically to evaluate long-term results of an abandoned technique. Median follow-up time was 21 years (range: 8 to 28). The average age at symptom start was 14 years (range: 9 to 17). Fourteen patients were operated bilaterally, while 15 were operated on the right side only and 33 on the left side only. No additional hip surgery for coxarthrosis as adults had been performed. At the clinical examination the mean hip-movement-sum was 220 degrees (range: 30 degrees to 300 degrees). Pain occurred in 31 hips. A limp was found in 23 patients, and 56 had no impairment of working ability. At radiologic examination, 30 patients showed sequelae of PCF, and 30 (48%) had bilateral signs of PCF at follow up.

Measurement of the absolute branching fraction of D0-->K-pi+.

We measure the absolute branching fraction for D(0)-->K(-)pi(+) using partial reconstruction of B(0)-->D(*+)Xl(-)nu(l) decays, in which only the charged lepton and the pion from the decay D(*+)-->D(0)pi(+) are used. Based on a data sample of 230 x 10(6) BB pairs collected at the Upsilon(4S) resonance with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC, we obtain B(D(0)-->K(-)pi(+)) = (4.007+/-0.037+/-0.072)%, where the first uncertainty is statistical and the second is systematic.

Observation of tree-level B decays with ss production from gluon radiation.

We report on our search for decays proceeding via a tree-level b-->c quark transition in which a gluon radiates into an ss[over ] pair. We present observations of the decays B;{-}-->D_{s};{+}K;{-}pi;{-} and B[over ];{0}-->D_{s};{+}K_{S};{0}pi;{-} and evidence for B;{-}-->D_{s};{+}K;{-}K;{-} and set upper limits on the branching fractions for B[over ];{0}-->D_{s};{+}K_{S};{0}pi;{-} and B;{-}-->D_{s};{+}K;{-}K;{-} using 383x10;{6} Upsilon(4S)-->BB[over ] events collected by the BABAR detector at SLAC. We present evidence that the invariant mass distributions of D_{s};{+}K;{-} pairs from B;{-}-->D_{s};{+}K;{-}pi;{-} decays are inconsistent with the phase-space model, suggesting the presence of charm resonances lying below the D_{s};{+}K;{-} threshold.

Observation of Y(3940) --> J/psiomega in B --> J/psiomegaK at BABAR.

We present a study of the decays B;{0,+}-->J/psiomegaK;{0,+} using 383x10;{6} BB[over ] events obtained with the BABAR detector at PEP-II. We observe Y(3940)-->J/psiomega, with mass 3914.6_{-3.4};{+3.8}(stat)+/-2.0(syst) MeV/c;{2}, and width 34_{-8};{+12}(stat)+/-5(syst) MeV. The ratio of B0 and B+ decay to YK is 0.27_{-0.23};{+0.28}(stat)-0.01+0.04(syst), and the relevant B0 and B+ branching fractions are reported.

Study of B meson decays with excited eta and eta' mesons.

Using 383 x 10(6) BBover pairs from the BABAR data sample, we report results for branching fractions of six charged B-meson decay modes, where a charged kaon recoils against a charmless resonance decaying to KKover* or etapipi final states with mass in the range (1.2-1.8) GeV/c2. We observe a significant enhancement at the low KKover* invariant mass which is interpreted as B+-->eta(1475)K+, find evidence for the decay B+-->eta(1295)K+, and place upper limits on the decays B+-->eta(1405)K+, B+-->f1(1285)K+, B+-->f1(1420)K+, and B+-->phi(1680)K+.

Measurements of CP-violating asymmetries in the decay B0-->K+K-K0.

We analyze the decay B0-->K+K-K0 using 383 x 10(6) BB events collected by the BABAR detector at SLAC to extract CP violation parameter values over the Dalitz plot. Combining all K+K-K0 events, we find ACP=-0.015+/-0.077+/-0.053 and beta eff = 0.352+/-0.076+/-0.026 rad, corresponding to a CP violation significance of 4.8 sigma. A second solution near pi/2-beta eff is disfavored with a significance of 4.5 sigma. We also report ACP and beta eff separately for decays to phi(1020)K0, f0(980)K0, and K+K-K0 with mK+K- > 1.1 GeV/c2.

Improved measurement of CP violation in neutral B decays to cc[over]s.

We present updated measurements of time-dependent CP asymmetries in fully-reconstructed neutral B decays to several CP eigenstates containing a charmonium meson. The measurements use a data sample of (383+/-4)x10(6) Upsilon(4S)-->BB[over] decays collected with the BABAR detector at the PEP-II B factory. We determine sin2beta = 0.714+/-0.032(stat)+/-0.018(syst) and |lambda|=0.952+/-0.022(stat)+/-0.017(syst).

Search for the Decay B+-->K+ tau-/+ mu+/-.

We present a search for the lepton flavor violating decay B+-->K+ tau-/+ mu+/- using 383 x 10;{6} BB[over ] events collected by the BABAR experiment. The branching fraction for this decay can be substantially enhanced in new physics models. The kinematics of the tau from the signal B decay are inferred from the K+, mu, and other B in the event, which is fully reconstructed in one of a variety of hadronic decay modes, allowing the signal B candidate to be fully reconstructed. We observe no excess of events over the expected background and set a limit of B(B+-->K+ tau mu)<7.7 x 10(-5) at 90% confidence level, where the branching fraction is for the sum of the K+ tau- mu+ and K+ tau+mu- final states. We use this result to improve a model-independent bound on the energy scale of flavor-changing new physics.