A steerable UV laser system for the calibration of liquid argon time projection chambers

A number of liquid argon time projection chambers (LAr TPCs) are being built or are proposed for neutrino experiments on long- and short baseline beams. For these detectors, a distortion in the drift field due to geometrical or physics reasons can affect the reconstruction of the events. Depending on the TPC geometry and electric drift field intensity, this distortion could be of the same magnitude as the drift field itself. Recently, we presented a method to calibrate the drift field and correct for these possible distortions. While straight cosmic ray muon tracks could be used for calibration, multiple coulomb scattering and momentum uncertainties allow only a limited resolution. A UV laser instead can create straight ionization tracks in liquid argon, and allows one to map the drift field along different paths in the TPC inner volume. Here we present a UV laser feed-through design with a steerable UV mirror immersed in liquid argon that can point the laser beam at many locations through the TPC. The straight ionization paths are sensitive to drift field distortions, a fit of these distortion to the linear optical path allows to extract the drift field, by using these laser tracks along the whole TPC volume one can obtain a 3D drift field map. The UV laser feed-through assembly is a prototype of the system that will be used for the MicroBooNE experiment at the Fermi National Accelerator Laboratory (FNAL).

Written survey on recently deceased patients in germany and switzerland: how do general practitioners see their role?

BACKGROUND General practitioners (GPs) play an important role in end-of-life care due to their proximity to the patient's dwelling-place and their contact to relatives and other care providers. METHODS In order to get a better understanding of the role which the GP sees him- or herself as playing in end-of-life care and which care their dying patients get, we conducted this written survey. It asked questions about the most recently deceased patient of each physician. The questionnaire was sent to 1,201 GPs in southern North Rhine-Westphalia (Germany) and the Canton of Bern (Switzerland). RESULTS Response rate was 27.5 % (n = 330). The average age of responding physicians was 54.5 years (range: 34-76; standard derivation: 7.4), 68 % of them were male and 45 % worked alone in their practice. Primary outcome measures of this observational study are the characteristics of recently deceased patients as well as their care and the involvement of other professional caregivers. Almost half of the most recently deceased patients had cancer. Only 3 to 16 % of all deceased suffered from severe levels of pain, nausea, dyspnea or emesis. More than 80 % of the doctors considered themselves to be an indispensable part of their patient's end-of-life care. Almost 90 % of the doctors were in contact with the patient's family and 50 % with the responsible nursing service. The majority of the GPs had taken over the coordination of care and cooperation with other attending physicians. CONCLUSION The study confirms the relevance of caring for dying patients in GPs work and provides an important insight into their perception of their own role.

MYB-FL controls gain and loss of floral UV absorbance, a key trait affecting pollinator preference and reproductive isolation

Adaptations to new pollinators involve multiple floral traits, each requiring coordinated changes in multiple genes. Despite this genetic complexity, shifts in pollination syndromes have happened frequently during angiosperm evolution. Here we study the genetic basis of floral UV absorbance, a key trait for attracting nocturnal pollinators. In Petunia, mutations in a single gene, MYB-FL, explain two transitions in UV absorbance. A gain of UV absorbance in the transition from bee to moth pollination was determined by a cis-regulatory mutation, whereas a frameshift mutation caused subsequent loss of UV absorbance during the transition from moth to hummingbird pollination. The functional differences in MYB-FL provide insight into the process of speciation and clarify phylogenetic relationships between nascent species.