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Using the non-perturbative numerical renormalisation group (NRG) we analyse purely fermionic as well as more complex Bose-Fermi quantum impurity systems on their equilibrium properties and beyond: We present an extensive exploration of real-time dynamics for various quenches using the time-dependent NRG. For the purely fermionic system, we use the Single-impurity Anderson model (SIAM) in which the impurity is a localised orbital hybridising with a surrounding conduction band. The model enables charge scattering with a pseudo-gap scattering rate and features a quantum critical point separating the local moment (LM) phase with an unscreened spin moment from a symmetric strong coupling (SSC) phase with a fractionally screened spin moment. The real-time dynamics of the local double occupancy nicely thermalises for quenches regarding the SSC phase. Whereas for quenches within or into the LM phase the double occupancy systematically deviates from thermal equilibrium for long times. A comparison with results of a recently published time-dependent Gutwiller approach reveals clear discrepancies since this approach restricts the formation of the local moment only on the impurity site. We extend the system by an additional bosonic bath leading to the Bose-Fermi Anderson model (BFAM) and study the influence of the additional bosonic degrees of freedom on the real-time dynamics. In equilibrium the bosonic bath features an additional quantum critical point leading to a localised phase once the coupling to a sub-ohmic bosonic bath exceeds a critical value. In general the coupled bosonic bath leads to a renormalisation of the Coulomb interaction. We show that the dynamics is influenced by the specific choice of the bath exponents. For a F-type combination the non-equilibrium dynamics can be completely reproduced by an effective purely fermionic SIAM while for a B-type combination the nature of the bosonic bath and the coupling strength has a profound impact on the electron dynamics which can only be partially understood by an effective SIAM. Furthermore, we investigate the spin dynamics of an initially polarised impurity spin which is coupled to a fermionic and a bosonic bath leading to the Bose-Fermi Kondo model (BFKM). Through the coupling to the fermionic bath the polarisation vanishes with time. We show that in analogy to the spin-boson model (SBM) an initially coupling to the bosonic bath affects the real-time dynamics fundamentally leading to a remaining polarisation for long times., Unter Verwendung der numerischen Renormierungsgruppe (NRG) analysieren wir rein fermionische als auch komplexere Bose-Fermi-Quantenstörstellensysteme auf ihre Gleichgewichtseigenschaften und darüber hinaus: Wir präsentieren eine umfangreiche Untersuchung der Realzeitdynamik für verschiedene Quenche unter Verwendung der zeitabhängigen NRG. Für das rein fermionsche System nutzen wir das Single-impurity-Anderson-Modell (SIAM), in dem die Störstelle ein lokalisiertes Orbital ist, das mit dem umgebenden Leitungsband hybridisiert. Das Modell ermöglicht Ladungssteuung mit einer Psedudogapstreurate und bildet einen quantenkritischen Punkt aus, der die Phase des lokalen Moments (LM) mit einem freien Spinmoment von der Phase der symmetrischen starken Kopplung (SSC) mit einem teilweise abgeschirmten Spin trennt. Die Realzeitdynamik der lokalen Doppelbesetzung thermalisiert für Quenche bezüglich der SSC Phase. Allerdings weicht die Doppelbesetzung für Quenche innerhalb oder in die LM Phase hinein für lange Zeiten vom thermischen Gleichgewichtswert systematisch ab. Wir sehen deutliche Abweichungen in der Dynamik im Vergleich zu Ergebnissen eines kürzlich veröffentlichen zeitabhängigen Gutzwiller-Ansatzes, da dieser Ansatz die Bildung des lokalen Moments auf die Störstelle beschränkt. Wir erweitern das System um ein zusätzliches bosonisches Bad, wodurch wir das Bose-Fermi-Anderson-Modell (BFAM) erhalten, und untersuchen den Einfluss der zusätzlichen bosonischen Freiheitsgrade auf die Realzeitdynamik. Im Gleichgewicht führt das bosonische Bad zu einem weiteren quantenkritischen Punkt, der den Übergang zu einer lokalisierten Phase beschreibt, sobald die Kopplung an das sub-ohmische bosonische Bad einen kritischen Wert übersteigt. Allgemein führt das bosonische Bad zu einer Renormierung der Coulomb-Wechselwirkung. Wir zeigen, dass die Dynamik von der speziellen Kombination der Badexponenten beeinflusst wird. Für eine fermionische Kombination (F-Typ) kann die Nichtgleichgewichtsdynamik vollständig durch ein effektives rein fermionisches SIAM reproduziert werden, wohingegen für eine bosonische Kombination (B-Typ) die Natur des bosonischen Bades und die Kopplungsstärke einen erheblichen Einfluss auf die Dynamik der Elektronen haben, welcher nur teilweise im Rahmen eines effektiven SIAM verstanden werden kann. Des Weiteren betrachten wir die Dynamik eines initial polarisierten Störstellenspins, der an ein fermionisches und ein bosonisches Bad koppelt. Dies betrachten wir im Rahmen des Bose-Fermi-Kondo-Modells (BFKM). Durch die Kopplung ans fermionische Bad verschwindet die Polarisation mit der Zeit. Wir zeigen, dass analog zum Spin-Boson-Modell (SBM) eine initiale Kopplung an das bosonische Bad die Realzeitdynamik derart beeinflusst, dass der Spin auch für große Zeiten polarisiert bleibt.

Clara Menéndez and colleagues conducted an open-label randomized controlled trial in HIV-negative pregnant women in Benin, Gabon, Mozambique, and Tanzania to evaluate the safety and efficacy of mefloquine compared to sulfadoxine-pyrimethamine for intermittent preventative therapy for malaria. Please see later in the article for the Editors' Summary, Background Intermittent preventive treatment in pregnancy (IPTp) with sulfadoxine-pyrimethamine (SP) is recommended by WHO to prevent malaria in African pregnant women. The spread of SP parasite resistance has raised concerns regarding long-term use for IPT. Mefloquine (MQ) is the most promising of available alternatives to SP based on safety profile, long half-life, and high efficacy in Africa. We evaluated the safety and efficacy of MQ for IPTp compared to those of SP in HIV-negative women. Methods and Findings A total of 4,749 pregnant women were enrolled in an open-label randomized clinical trial conducted in Benin, Gabon, Mozambique, and Tanzania comparing two-dose MQ or SP for IPTp and MQ tolerability of two different regimens. The study arms were: (1) SP, (2) single dose MQ (15 mg/kg), and (3) split-dose MQ in the context of long lasting insecticide treated nets. There was no difference on low birth weight prevalence (primary study outcome) between groups (360/2,778 [13.0%]) for MQ group and 177/1,398 (12.7%) for SP group; risk ratio [RR], 1.02 (95% CI 0.86–1.22; p = 0.80 in the ITT analysis). Women receiving MQ had reduced risks of parasitemia (63/1,372 [4.6%] in the SP group and 88/2,737 [3.2%] in the MQ group; RR, 0.70 [95% CI 0.51–0.96]; p = 0.03) and anemia at delivery (609/1,380 [44.1%] in the SP group and 1,110/2743 [40.5%] in the MQ group; RR, 0.92 [95% CI 0.85–0.99]; p = 0.03), and reduced incidence of clinical malaria (96/551.8 malaria episodes person/year [PYAR] in the SP group and 130/1,103.2 episodes PYAR in the MQ group; RR, 0.67 [95% CI 0.52–0.88]; p = 0.004) and all-cause outpatient attendances during pregnancy (850/557.8 outpatients visits PYAR in the SP group and 1,480/1,110.1 visits PYAR in the MQ group; RR, 0.86 [0.78–0.95]; p = 0.003). There were no differences in the prevalence of placental infection and adverse pregnancy outcomes between groups. Tolerability was poorer in the two MQ groups compared to SP. The most frequently reported related adverse events were dizziness (ranging from 33.9% to 35.5% after dose 1; and 16.0% to 20.8% after dose 2) and vomiting (30.2% to 31.7%, after dose 1 and 15.3% to 17.4% after dose 2) with similar proportions in the full and split MQ arms. The open-label design is a limitation of the study that affects mainly the safety assessment. Conclusions Women taking MQ IPTp (15 mg/kg) in the context of long lasting insecticide treated nets had similar prevalence rates of low birth weight as those taking SP IPTp. MQ recipients had less clinical malaria than SP recipients, and the pregnancy outcomes and safety profile were similar. MQ had poorer tolerability even when splitting the dose over two days. These results do not support a change in the current IPTp policy. Trial registration ClinicalTrials.gov NCT 00811421; Pan African Clinical Trials Registry PACTR 2010020001429343 Please see later in the article for the Editors' Summary, Editors' Summary Background Half the world's population is at risk of malaria, a mosquito-borne parasitic disease that kills about 600,000 people every year. Most of these deaths occur among young children in sub-Saharan Africa but pregnant women and their unborn children living in Africa are also very vulnerable to malaria. Infection with malaria during pregnancy can cause severe maternal anemia (reduced red blood cell numbers), stillbirths, and pre-term and low-birthweight babies, and is responsible for the deaths of many African babies and women. To prevent this loss of life, the World Health Organization (WHO) recommends a three-pronged approach—the delivery to pregnant women of the antimalarial drug sulfadoxine-pyrimethamine (SP) at each scheduled antenatal care visit given at least one month apart (intermittent preventive treatment in pregnancy; IPTp), the use of insecticide treated bed nets to protect pregnant women from the bites of infected mosquitoes, and effective case management of pregnant women with malarial illness. Why Was This Study Done? IPTp with SP reduces the delivery of low-birth-weight babies and neonatal deaths but malaria parasites are becoming resistant to SP. Thus, other antimalarial drugs need to be evaluated for use in IPTp. Suitable drugs need to remain in the body for a long time to maximize their prophylactic (preventative) effect, they need to be given as a single dose at antenatal clinic visits to ensure compliance, and they must not harm the unborn child. In this open-label, randomized controlled trial (RCT), the researchers compare the efficacy and safety of IPTp with SP and mefloquine (MQ, an antimalarial drug that matches these criteria) in HIV-negative women living in Africa. The study also compares the tolerability of two MQ regimens. RCTs compare outcomes in groups of people chosen to receive different interventions through the play of chance; in open-label RCTs, both the researchers and the study participants know which treatment is being administered. IPTp with SP is only recommended for HIV-negative women because SP interacts with cotrimoxazole, which is routinely given to HIV-positive individuals to prevent infections. What Did the Researchers Do and Find? The researchers assigned 4,749 pregnant women in Benin, Gabon, Mozambique, and Tanzania to one of three study groups. Participants in the SP and MQ groups received two doses of SP or MQ, respectively, administered at least one month apart. Participants in the split-dose MQ group received each MQ dose as half doses given on consecutive days. The prevalence of low-birth-weight deliveries (the study's primary outcome; the prevalence of a condition is the proportion of a population with that condition) was similar in the SP group and in the combined MQ groups. However, compared to women who received SP, women who received MQ had a lower risk of parasitemia (parasites in the blood), a lower risk of anemia at delivery, fewer episodes of clinical malaria, and fewer outpatient attendances. The prevalence of placental infection with malaria parasites and of adverse pregnancy outcomes such as stillbirth was similar in all the study groups. Finally, the tolerability of IPTp was poorer in the two MQ intervention groups than in the SP group, but similar proportions of adverse events (mainly dizziness and vomiting) were reported for the two MQ dosing regimens. What Do These Findings Mean? These findings indicate that HIV-negative African women taking MQ for IPTp had a similar risk of a low-birth-weight delivery (the study's primary outcome) and lower risk of malaria illness during pregnancy than women taking SP for IPTp. Because the study did not have a no-IPTp arm (for ethical reasons), these findings provide no information about the efficacy or safety or either MQ or SP per se; these findings only indicate that MQ is no more efficacious than SP in the prevention of low-birth-weight babies. Moreover, because the study was open-label, the accuracy of the findings related to the tolerability and safety of MQ compared to SP may be limited because of biases in the assessment of safety outcomes. Given that the MQ dose used here for IPTp was associated with poorer tolerability than that of SP, these findings do not support the use of MQ instead of SP for IPTp. Additional Information Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001733. A related PLOS Medicine Research Article by Raquel González and colleagues examines IPTp-MQ in HIV-infected women receiving cotrimoxazole prophylaxis This study is further discussed in a PLOS Medicine Perspective by Richard Steketee. Information is available from the World Health Organization on malaria (in several languages) and on malaria in pregnancy; information on IPTp and the updated WHO policy recommendation on IPTp with SP are available; the 2013 World Malaria Report provides details of the current global malaria situation The US Centers for Disease Control and Prevention also provides information on malaria; a personal story about malaria in pregnancy is available Information is available from the Roll Back Malaria Partnership on all aspects of global malaria control, including information on malaria in pregnancy The Malaria in Pregnancy Consortium is undertaking research into the prevention and treatment of malaria in pregnancy MedlinePlus provides links to additional information on malaria (in English and Spanish)

Seit der Finanz- und Wirtschaftskrise in 2008/2009 wird die wertorientierte Steuerung, die seit den 1990er-Jahren in der Unternehmenspraxis als State-of-the-Art einer erfolgreichen Unternehmensführung gilt, zunehmend hinterfragt. Der vorliegende Beitrag zeigt, dass das Grundmodell der Wertorientierung einer nachhaltigen Unternehmensführung zwar per se nicht widerspricht, dass aber in der praktischen Umsetzung die Vielzahl strenger Annahmen, die diesem Grundmodell implizit unterliegen, häufig nicht erfüllt ist. Um nicht selbst zumKrisenauslöser zu werden, muss die bisher primär auf finanzielle Führung ausgerichtete wertorientierte Steuerung daher im Sinne eines ganzheitlichen Management Control-Ansatzes auch um handlungsorientierte bzw. soziale Steuerungsinstrumente ergänzt werden.