122 research outputs found

    P5_5 Drag on Dragons

    Get PDF
    By comparison of the lift and drag forces of two dragons, one fat with a supplementary hydrogen source and one thin without, we have calculated the turning point velocity in which it is more beneficial to be either size. The wind velocity, or turning point velocity, was found to be 14.9 ms-1; below this value the fat dragon will be more advantageous and, conversely above, the thin dragon

    P5_6 A Race in Space

    Get PDF
    By comparing solar and laser radiation sources, each driving a nano-satellite of mass 1 gram, we find that the solar sail is more advantageous up to 9.5 AU, and the laser sail is better beyond this distance. We also find that the laser sail has a constant acceleration throughout, but the solar sail acceleration decreases at a velocity of 150,000 ms-1

    P5_4 Where’s Wall-E?

    Get PDF
    We have calculated that a fire extinguisher under incompressible flow has a ∆v = 4.1 ms-1 and a ∆v = 8.4 ms-1 under adiabatic flow. If Wall-E was to use fire extinguishers as a method of propulsion in space rather than NASA’s MMU (with ∆v = 25 ms-1) he would require 10 fire extinguishers for incompressible flow and 4 for adiabatic flow.

    Genetic research: the role of citizens, public health and international stakeholders

    Get PDF
    Background: Genetic research has become an indispensable instrument for medical research, and the subjects involved have both divergent and convergent interests. Objective: The possibility of having more detailed genetic information undoubtedly offers benefits for the health of the subject, but could also pose risks and make the subject vulnerable to discrimination. Methods: The scientific community has viewed very favorably the public health utility of family history, in which data from a family whose members suffer from chronic pathologies is collected and filed, in order to develop a sort of “stratification of family risk.” Even though in the last decade the scientific and juridical literature has contributed greatly to the topic of biobanks, the perplexities that continue to surround this theme give the idea that current ethical protocols on research are inadequate. Results: Researchers, citizens, International stakeholders, mass media, Public Health and Governments play a key role in genetic research. It is obvious that the methods used for genetic research do not present intrinsic risks; they are much less dangerous than other activities of diagnosis and research. Before authorizing a research project, it is important to reflect on the responsibility and transparency of the studies to be conducted, and on the impact they may have on the interests of public health. Conclusion: We believe that the highest priority need is to develop a common language on the theme, as is the case in the sphere of clinical experimentation where rules of good clinical practice, albeit at times conflicting, have led to uniform convergences in the scientific world on the points to be actuated

    Numerical investigation of 3-D constraint effects on brittle fracture in SE(B) and C(T) specimens

    Get PDF
    This investigation employs 3-D nonlinear finite element analyses to conduct an extensive parametric evaluation of crack front stress triaxiality for deep notch SE(B) and C(T) specimens and shallow notch SE(B) specimens, with and without side grooves. Crack front conditions are characterized in terms of J-Q trajectories and the constraint scaling model for cleavage fracture toughness proposed previously by Dodds and Anderson. The 3-D computational results imply that a significantly less strict size/deformation limit, relative to the limits indicated by previous plane-strain computations, is needed to maintain small-scale yielding conditions at fracture by a stress- controlled, cleavage mechanism in deep notch SE(B) and C(T) specimens. Additional new results made available from the 3-D analyses also include revised {eta}-plastic factors for use in experimental studies to convert measured work quantities to thickness average and maximum (local) J-values over the crack front

    Traditional and transgenic strategies for controlling tomato-infecting begomoviruses

    Full text link

    Whole-genome sequencing reveals host factors underlying critical COVID-19

    Get PDF
    Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease
    • 

    corecore