Piezoelectric nanoelectromechanical resonators based on aluminum nitride thin films

We demonstrate piezoelectrically actuated, electrically tunable nanomechanical resonators based on multilayers containing a 100-nm-thin aluminum nitride (AlN) layer. Efficient piezoelectric actuation of very high frequency fundamental flexural modes up to ~80 MHz is demonstrated at room temperature. Thermomechanical fluctuations of AlN cantilevers measured by optical interferometry enable calibration of the transduction responsivity and displacement sensitivities of the resonators. Measurements and analyses show that the 100 nm AlN layer employed has an excellent piezoelectric coefficient, d_(31)=2.4 pm/V. Doubly clamped AlN beams exhibit significant frequency tuning behavior with applied dc voltage

Decision for reconstructive interventions of the upper limb in individuals with tetraplegia: the effect of treatment characteristics

Objective: To determine the effect of treatment characteristics on the\ud decision for reconstructive interventions for the upper extremities (UE) in\ud subjects with tetraplegia. - \ud Setting: Seven specialized spinal cord injury centres in the Netherlands. - \ud Method: Treatment characteristics for UE reconstructive interventions were\ud determined. Conjoint analysis (CA) was used to determine the contribution\ud and the relative importance of the treatment characteristics on the decision\ud for therapy. Therefore, a number of different treatment scenarios using these\ud characteristics were established. Different pairs of scenarios were presented\ud to subjects who were asked to choose the preferred scenario of each set. - \ud Results: forty nine subjects with tetraplegia with a stable C5, C6 or C7\ud lesion were selected. All treatment characteristics significantly influenced\ud the choice for treatment. Relative importance of treatment characteristics\ud were: intervention type (surgery or surgery with FES implant) 13%, number\ud of operations 15%, in patient rehabilitation period 22%, ambulant\ud rehabilitation period 9%, complication rate 15%, improvement of elbow\ud function 10%, improvement of hand function 15%. In deciding for therapy\ud 40% of the subjects focused on one characteristic. - \ud Conclusion: CA is applicable in Spinal Cord Injury medicine to study the\ud effect of health outcomes and non-health outcomes on the decision for\ud treatment. Non-health outcomes which relate to the intensity of treatment\ud are equally important or even more important than functional outcome in the\ud decision for reconstructive UE surgery in subjects with tetraplegia

Critical comments on the WHO-UNEP State of the Science of Endocrine Disrupting Chemicals – 2012

AbstractEarly in 2013, the World Health Organization (WHO) released a 2012 update to the 2002 State of the Science of Endocrine Disrupting Chemicals. Several significant concerns have been identified that raise questions about conclusions reached in this report regarding endocrine disruption. First, the report is not a state-of-the-science review and does not follow the 2002 WHO recommended weight-of-evidence approach. Second, endocrine disruption is often presumed to occur based on exposure or a potential mechanism despite a lack of evidence to show that chemicals are causally established as endocrine disruptors. Additionally, causation is often inferred by the presentation of a series of unrelated facts, which collectively do not demonstrate causation. Third, trends in disease incidence or prevalence are discussed without regard to known causes or risk factors; endocrine disruption is implicated as the reason for such trends in the absence of evidence. Fourth, dose and potency are ignored for most chemicals discussed. Finally, controversial topics (i.e., low dose effects, non-monotonic dose response) are presented in a one-sided manner and these topics are important to understanding endocrine disruption. Overall, the 2012 report does not provide a balanced perspective, nor does it accurately reflect the state of the science on endocrine disruption

Courtship, egg sac construction, and maternal care in Kukulcania hibernalis, with information on the courtship of Misionella mendensis (Araneae, Filistatidae)

Morphological and behavioural traits place Filistatidae basally within Araneomorphae, although some features, such as their continuing to moult after reaching adulthood, are reminiscent of mygalomorph spiders. This paper describes the courtship behaviour and other aspects of the reproductive biology of Kukulcania hibernalis and Misionella mendensis, and compares this information with that from related filistatid species and with Mygalomorphae. K. hibernalis has some unique behaviours during courtship (e.g. male lays threads on female web); other behaviours are probably widespread within Filistatidae (e.g. male uses the tarsi and metatarsi of one of his legs to rub the basal sections of the female’s legs and the sides of her cephalothorax). Some other behaviours seem more similar to Mygalomorphae than to those of other, more derived Araneomorphae. These include male construction of a large sperm web, and the positions of male and female facing each other during copulation, with the male holding the female cephalothorax lifted while insertions occur, similar to some mygalomorphs. The adult female K. hibernalis and the first instar spiderlings (outside the egg sac) feed simultaneously on the same prey, but spiderlings are also capable of cooperating during the attack of large prey. The courtship behaviour supports the hypothesis that places Filistatidae basally within Araneomorphae.UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí