We present the first demonstration of a new mechanism for temporal compression of ultrashort light pulses that operates at high (i.e., ionizing) intensities. By propagating pulses inside a hollow waveguide filled with low-pressure argon gas, we demonstrate a self-compression from 30 to 13 fs, without the need for any external dispersion compensation. Theoretical models show that 3D spatiotempor...

Optical pulses with 1.1-mJ energy and 5.5-fs duration have been generated at 1-kHz repetition rate from a chirped pulse amplification Ti:Sapphire laser incorporating a differentially pumped hollow-fiber chirped-mirror compressor. The effects of self-focusing and multi-photon ionization during the beam propagation were minimized by differentially pumping the hollow fiber filled with neon. The sp...

Nonlinear interactions between different disturbances in a hypersonic boundary layer are investigated by bispectral analysis. Experiments performed on flared cone at Mach 6 using fast-response pressure sensors and Rayleigh-scattering flow visualization. At the modal growth stage, phase-coupled sum have profound effects of disturbances. Then, difference contribute to spectral broadening. final n...

h h p f s i e o t vercoming Obstacles to Health: a Report from the Robert Wood Johnson Foundation to the Commission to Build a Healthier America was issued rom the foundation to the commission at the commision’s 2008 public launch. The purpose was to present the oundation’s rationale for establishing the commission nd provide a conceptual framework and scientifıc guidnce for the commission’s wo...

When a nucleus undergoes beta decay via the electron capture reaction, it emits an electron neutrino. The neutrino emission gives a small recoil to the atom, which can be experimentally observed as a Doppler broadening on subsequently emitted gamma rays. Using the two-axis flat-crystal spectrometer GAMS4 and the electron capture reaction in (152)Eu, the motion of atoms having an excess kinetic ...

Over the past dozen or so years neuroethics has become a rich and dynamic field that has brought together individuals from a variety of disciplines and interests to consider issues that lie at the intersection of ethics and neuroscience. During this period there has been a significant amount of important empirical and philosophical work on a range of topics at this intersection; however, there ...

Travel is an integral part of a career as a life scientist — in fact, you can’t become a scientist without travelling. In the early stages it’s quite natural to have serious doubts about whether you’re on the right career path. Traveling lets you forget these worries and puts things in perspective. You will then begin to see whether you are just worrying unecessarily or whether you are really f...

(The units can be presented as either single or double lectures) DNA origami pores DNA structure (primary, secondary, tertiary structure; A, B, Z-DNA; canonical and non-canonical base pairs, RNA vs DNA, Holiday and other multi-way junctions) DNA biochemistry (enzymatic synthesis, mechanism, replication fork, helicase) DNA chemistry (solid-phase synthesis, chemical modification at bases, nucleos...

A new procedure aiming at disentangling the instrumental profile broadening and the relevant X-ray powder diffraction (XRPD) profile shape is presented. The technique consists of three steps: denoising by means of wavelet transforms, background suppression by morphological functions and deblurring by a Lucy–Richardson damped deconvolution algorithm. Real XRPD intensity profiles of ceria samples...

Pressure-jump initiated time-resolved x-ray diffraction studies of dynamics of the hydration of the hexagonal phase in biological membranes show that (i) the relaxation of the unit cell spacing is non-exponential in time; (ii) the Bragg peaks shift smoothly to their final positions without significant broadening or loss in crystalline order. This suggests that the hydration is not diffusion lim...