University of Hamburg

About: University of Hamburg is a education organization based out in Hamburg, Germany. It is known for research contribution in the topics: Population & Laser. The organization has 45564 authors who have published 89286 publications receiving 2850161 citations. The organization is also known as: Hamburg University.

Synthesized light transients.

Abstract: Manipulation of electron dynamics calls for electromagnetic forces that can be confined to and controlled over sub-femtosecond time intervals. Tailored transients of light fields can provide these forces. We report on the generation of subcycle field transients spanning the infrared, visible, and ultraviolet frequency regimes with a 1.5-octave three-channel optical field synthesizer and their attosecond sampling. To demonstrate applicability, we field-ionized krypton atoms within a single wave crest and launched a valence-shell electron wavepacket with a well-defined initial phase. Half-cycle field excitation and attosecond probing revealed fine details of atomic-scale electron motion, such as the instantaneous rate of tunneling, the initial charge distribution of a valence-shell wavepacket, the attosecond dynamic shift (instantaneous ac Stark shift) of its energy levels, and its few-femtosecond coherent oscillations.

Genome-wide association analysis of more than 120,000 individuals identifies 15 new susceptibility loci for breast cancer

Abstract: Genome-wide association studies (GWAS) and large-scale replication studies have identified common variants in 79 loci associated with breast cancer, explaining ∼14% of the familial risk of the disease. To identify new susceptibility loci, we performed a meta-analysis of 11 GWAS, comprising 15,748 breast cancer cases and 18,084 controls together with 46,785 cases and 42,892 controls from 41 studies genotyped on a 211,155-marker custom array (iCOGS). Analyses were restricted to women of European ancestry. We generated genotypes for more than 11 million SNPs by imputation using the 1000 Genomes Project reference panel, and we identified 15 new loci associated with breast cancer at P < 5 × 10(-8). Combining association analysis with ChIP-seq chromatin binding data in mammary cell lines and ChIA-PET chromatin interaction data from ENCODE, we identified likely target genes in two regions: SETBP1 at 18q12.3 and RNF115 and PDZK1 at 1q21.1. One association appears to be driven by an amino acid substitution encoded in EXO1.

Earth system models of intermediate complexity: closing the gap in the spectrum of climate system models

Abstract: We propose a new perspective on the hierarchy of climate models which goes beyond the ''classical'' climate modeling pyramid that is restricted mainly to atmospheric processes, Most notably, we introduce a new indicator, called ''integration'', which characterizes the number of interacting components of the climate system being explicitly described in a model. The location of several model types, from conceptual to comprehensive, is presented in a new spectrum of climate system models. In particular. the location of the Earth system Models of Intermediate Complexity (EMICs) in this spectrum is discussed in some detail and examples are given, which indicate that there is currently a broad range of EMICs in use. In some EMICs, the number of processes and/or the detail of description is reduced for the sake of simulating the feedbacks between as many components of the climate system as feasible. Others, with a lesser degree of interaction, or ''integration'', are used for long-term ensemble simulations to study specific aspects of climate variability. EMICs appear to be closer to comprehensive coupled models of atmospheric and oceanic circulation (CGCMs) than to ''conceptual'' or ''box'' models. We advocate that EMICs be considered as complementary to CGCMs and conceptual models, because we believe that there is an advantage of having a spectrum of climate system models which are designed to tackle specific aspects of climate and which together provide the proper tool for climate system modeling.