Humboldt University of Berlin

About: Humboldt University of Berlin is a education organization based out in Berlin, Germany. It is known for research contribution in the topics: Population & Transplantation. The organization has 33671 authors who have published 61781 publications receiving 1908102 citations. The organization is also known as: Humboldt-Universität zu Berlin & Universitas Humboldtiana Berolinensis.

The Transaction between Parents' Perceptions of their Children's Shyness and their Parenting Styles

Abstract: In recent years, researchers have examined factors that ''determine'' parenting beliefs, styles, and behaviours. One potential determinant of parenting is the child him/herself. Child characteristics, such as temperament, have been cited as evocative influences on parenting beliefs and behaviours. The primary purpose of this study was to investigate the longitudinal relations between children's social wariness/inhibition and parents' beliefs about how to best socialise their children. Questionnaire data on child temperament and parenting practices were collected from the parents (mothers and fathers) of sixty 2-year-olds; identical data were collected 2 years later. Observations of inhibited behaviour were taken at two years. Results indicated that few differences existed between mothers' and fathers' expressed parenting styles at ages 2 and 4 years. Second, parental perceptions of child shyness at age 2 were: (a) stable to age 4; and (b) predicted a lack of encouragement of independence at age 4. Third, ...

Modern aldol methods for the total synthesis of polyketides.

Abstract: The aldol reaction is one of the most important methods for the stereoselective construction of polyketide natural products, not only for nature but also for synthetic chemistry. The tremendous development in the field of aldol additions during the last 30 years has led to more and more total syntheses of complicated natural products. This Review illustrates by means of selected syntheses of natural products the new variants of the aldol addition. This includes aldol additions with various metal enolates, as well as metal-complex-catalyzed, organocatalytic, and biocatalytic methods.

Primary particle acceleration above 100 TeV in the shell-type supernova remnant RX J1713.7-3946 with deep HESS observations

Abstract: We present deep H.E.S.S. observations of the supernova remnant (SNR) RX J1713.7-3946. Combining data of three years - from 2003 to 2005 - we obtain significantly increased statistics and energy coverage as compared to earlier 2003 & 2004 results. The data are analysed separately for the different years. Very good agreement of the gamma-ray morphology and the differential spectra is found when comparing the three years. The combined gamma-ray image of the 2004 and 2005 data reveals the morphology of RX J1713.7-3946 with unprecedented precision. An angular resolution of 0.06 deg is achieved, revealing the detailed structure of the remnant. The combined spectrum of all three years extends over three orders of magnitude, with significant gamma-ray emission approaching 100 TeV. The cumulative significance above 30 TeV is 4.8 sigma, while for energies between 113 and 294 TeV an upper limit on the gamma-ray flux of 1.6 x 10^-16 cm^-2 s^-1 is obtained. The energy coverage of the H.E.S.S. data is presumably at the limit of present generation Cherenkov telescopes. The measurement of significant gamma-ray emission beyond 30 TeV formally implies the existence of primary particles of at least that energy. However, for realistic scenarios of very-high-energy gamma-ray production, the Inverse Compton scattering of very-high-energy electrons and pi^0 decay following inelastic proton-proton interactions, the measured gamma-ray energies imply that efficient acceleration of primary particles to energies exceeding 100 TeV is taking place in the shell of the SNR RX J1713.7-3946.

Organic semiconductor density of states controls the energy level alignment at electrode interfaces.

Abstract: Minimizing charge carrier injection barriers and extraction losses at interfaces between organic semiconductors and metallic electrodes is critical for optimizing the performance of organic (opto-) electronic devices. Here, we implement a detailed electrostatic model, capable of reproducing the alignment between the electrode Fermi energy and the transport states in the organic semiconductor both qualitatively and quantitatively. Covering the full phenomenological range of interfacial energy level alignment regimes within a single, consistent framework and continuously connecting the limiting cases described by previously proposed models allows us to resolve conflicting views in the literature. Our results highlight the density of states in the organic semiconductor as a key factor. Its shape and, in particular, the energy distribution of electronic states tailing into the fundamental gap is found to determine both the minimum value of practically achievable injection barriers as well as their spatial profile, ranging from abrupt interface dipoles to extended band-bending regions.

Health and Well–Being in the Young Old and Oldest Old

Abstract: Most individuals experience a decline in health status during old age. Paradoxically, there are proposals that older adults nevertheless maintain a positive sense of well–being, an indicator of successful aging. Data from the Berlin Aging Study (BASE: Baltes & Mayer, 1999), a locally representative sample of men and women aged 70 to 100+ (N= 516, M= 85 years), suggest that cumulative health–related chronic life strains set a constraint on the potential of oldest old individuals to experience the positive side of life. The young old in BASE reported significantly higher positive SWB than did the oldest old. Chronic illness and functional impairments (e.g., vision, hearing, mobility, strength) limit well–being especially in very old age.