Practical tips and tricks in measuring strain, strain rate and twist for the left and right ventricles.

Strain imaging provides an accessible, feasible and non-invasive technique to assess cardiac mechanics. Speckle tracking echocardiography (STE) is the primary modality with the utility for detection of subclinical ventricular dysfunction. Investigation and adoption of this technique has increased significantly in both the research and clinical environment. It is therefore important to provide information to guide the sonographer on the production of valid and reproducible data. The focus of this review is to (1) describe cardiac physiology and mechanics relevant to strain imaging, (2) discuss the concepts of strain imaging and STE and (3) provide a practical guide for the investigation and interpretation of cardiac mechanics using STE

A red knot as a black swan:How a single bird shows navigational abilities during repeat crossings of the Greenland Icecap

Despite the wealth of studies on seasonal movements of birds between southern nonbreeding locations and High Arctic breeding locations, the key mechanisms of navigation during these migrations remain elusive. A flight along the shortest possible route between pairs of points on a sphere ('orthodrome') requires a bird to be able to assess its current location in relation to its migration goal and to make continuous adjustment of heading to reach that goal. Alternatively, birds may navigate along a vector with a fixed orientation ('loxodrome') based on magnetic and/or celestial compass mechanisms. Compass navigation is considered especially challenging for summer migrations in Polar regions, as continuous daylight and complexity in the geomagnetic field may complicate the use of both celestial and magnetic compasses here. We examine the possible use of orientation mechanisms during migratory flights across the Greenland Icecap. Using a novel 2 g solar-powered satellite transmitter, we documented the flight paths travelled by a female red knotCalidris canutus islandicaduring two northward and two southward migrations. The geometry of the paths suggests that red knots can migrate across the Greenland Icecap along the shortest-, orthodrome-like, path instead of the previously suggested loxodrome path. This particular bird's ability to return to locations visited in a previous year, together with its sudden course changes (which would be appropriate responses to ambient wind fields), suggest a map sense that enables red knots to determine location, so that they can tailor their route depending on local conditions

Incidence and survival of retinoblastoma in the Netherlands: a register based study 1862-1995

AIM—The aim of this study was to determine the (time trends in) incidence and survival of hereditary (familial and sporadic) and non-hereditary retinoblastoma for male and female patients born in the Netherlands between 1862 and 1995.
METHOD—The national retinoblastoma register was updated and now consists of 955 patients. The missing dates of death were obtained from the municipal registers and the Central Bureau of Genealogy in The Hague. Mortality was compared with the Dutch vital statistics.
RESULTS—From 1862 to 1995 no significant differences in incidence for retinoblastoma were found in the hereditary subgroups. Further, no significant differences between males and females were found, both overall and in the hereditary subgroups. The average incidence of retinoblastoma increased untill 1944, probably due to incompleteness of the register, and stabilised after 1945 (1 per 17 000 live births). From 1900 to 1995 the standardised mortality ratio increased for hereditary retinoblastoma patients from 2.9 to 9.0 and decreased for non-hereditary retinoblastoma patients from 1.9 to 1.0.
CONCLUSION—Although survival for retinoblastoma was significantly better after 1945 than before, in comparison with the Dutch population the mortality between 1900 and 1990 increased for the hereditary and decreased for the non-hereditary retinoblastoma patients.


The radiation tolerance of specific optical fibres exposed to 650 kGy(Si) of ionizing radiation

The LHC upgrade will extensively increase the area of silicon detectors used in the ATLAS experiment and require substantial changes to the readout system of both the ATLAS and CMS experiments. The two experiments are expected to use optical systems for part of the data and control paths which must withstand levels of radiation equivalent to a dose of approximately 400 kGy(Si) at 30 cm from the collision region (including a safety factor of 1.5). As part of the search for acceptably radiation hard optical fibres, four Graded Index multimode (GRIN) optical fibres and one single-mode (SM) fibre were tested to 650 kGy(Si) equivalent dose. One of the GRIN fibres was also tested at 5 different dose rates, in order to understand the dose rate effects. These tests have validated the radiation tolerance of a single-mode fibre and two multimode fibres for use at the SLHC for warm operation. Some interesting features of the time dependence of the fibre radiation damage and future plans are discussed. © 2009 IOP Publishing Ltd and SISSA

Paracentric inversion inv(11) (q21q23) in the Netherlands

We report the result of investigations from 20 families with 72 carriers of the paracentric inversion inv(11)(q21q23) in the Netherlands. There is no increase in the rate of spontaneous abortions among carriers of the inversion or their partners. Also, so far, there are no children with recombinant chromosomes arising from the inversion. It is doubtful whether prenatal diagnosis would be helpful to carriers of this inversion. The results of the genealogy study and geographical distribution are discussed; it is suggested that all the families have arisen from a single mutation

Irradiation Studies of Multimode Fibres for use in ATLAS Front-end Links

The radiation tolerance of three multimode optical fibres has been investigatedto establish their suitability for use in the front-end data links of the ATLAS experiment. Both gamma and neutron irradiation studies are reported. A step-index fibre with a pure silica core showed an induced attenuation of $\sim$0.05~dB/mat 330~kGy(Si) and 1$\times$10$^{15}$~n(1~MeV~Si)/cm$^{2}$ and is suitablefor use with the inner detector links which operate at 40-80~Mb/s. A graded-indexfibre with a predominantly germanium doped core exhibits an induced attenuation of $\sim$0.1~dB/mat 800~Gy(Si) and 2$\times$10$^{13}$~n(1~MeV~Si)/cm$^{2}$ and is suitable for the calorimeterlinks which operate at 1.6~Gb/s. Measurements of the dose rate dependence of the induced attenuation indicate that the attenuation in ATLAS will be lower