We quantize a string in the de Sitter background, and we find that the mass spectrum is modified by a term which is quadratic in oscillating numbers, and also proportional to the square of the Hubble constant.

We present an open source physics engine specialised for multi-cellular artificial organisms simulations. It is computationally efficient in comparison to gas-based and finite element models and more realistic than standard mass-springdamper systems. Introduction Morphogenetic engineering can often make good use of some biologically plausible improvements. Mechanics, in particular, are quite im...

Intrafraction motion caused by breathing requires increased treatment margins for chest and abdominal radiotherapy and may lead to 'motion artefacts' in dose distributions during intensity modulated radiotherapy (IMRT). Technologies such as gated radiotherapy may significantly increase the treatment time, while breath-hold techniques may be poorly tolerated by pulmonarily compromised patients. ...

Current silicon photonics phased arrays based on waveguide gratings enable beam steering with no moving parts. However, they suffer from a trade-off between beam divergence and field of view. Here, we show a platform based on silicon-nitride/silicon that achieves simultaneously minimal beam divergence and maximum field of view while maintaining performance that is robust to fabrication variatio...

The beam delivery system of the carbon ion therapy at GSI has been modified to perform beam tracking [1,2]. Beam tracking is achieved by monitoring the target motion and by adapting the pencil beam in lateral (magnetically) and in longitudinal direction (motorized wedge absorbers). The updated integrated system was experimentally tested for left-right target motion with depth changes that were ...

From 1997 to 2008 the treatment of more than 400 patients with C ions at the experimental heavy ion treatment facility at GSI has been successfully monitored in vivo and in situ by means of 3D in-beam PET. The promising clinical results of the ion therapy for static tumor entities encourages to apply it to more frequent ones like lung cancer. Due to the sensitivity of the ion range to density c...

1 Cross sections and reaction rates 2 Consider a thin target of thickness dx and number density of targets nt being bombarded by a beam of number density Nb moving at velocity v. Each target nucleus presents a target area 3⁄4 { if one of the bombarding particles passes within the area 3⁄4, interaction (scattering, for example) occurs, otherwise not. Now if the beam covers an area A, the fractio...

background: in radiation treatment of moving targets located in thorax region of patient body, the delivered dose does not match with the planned treatment, resulting in some over and under dosage in the tumor volume, as a function of motion magnitude and frequency. several efforts have been done to investigate the target motion effects on dose distribution in the target and surrounding normal ...

For radiotherapy with external beams, quality assurance (QA) of beam delivery is mandatory. Dynamical irradiation which changes parameters of beam delivery devices during the irradiation has to be assessed with a great caution. At GSI a dynamic beam delivery system, so called beam tracking system [1] was developed and integrated into the GSI therapy system [2] to irradiate moving tumours with i...