Macroscopic Quantum Fluctuations in the Josephson Dynamics of Two Weakly Linked Bose-Einstein Condensates

We study the quantum corrections to the Gross-Pitaevskii equation for two weakly linked Bose-Einstein condensates. The goals are: 1) to investigate dynamical regimes at the borderline between the classical and quantum behaviour of the bosonic field; 2) to search for new macroscopic quantum coherence phenomena not observable with other superfluid/superconducting systems. Quantum fluctuations renormalize the classical Josephson oscillation frequencies. Large amplitude phase oscillations are modulated, exhibiting collapses and revivals. We describe a new inter-well oscillation mode, with a vanishing (ensemble averaged) mean value of the observables, but with oscillating mean square fluctuations. Increasing the number of condensate atoms, we recover the classical Gross-Pitaevskii (Josephson) dynamics, without invoking the symmetry-breaking of the Gauge invariance.Comment: Submitte

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

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

Regulating biomedicine in Europe and North America: A qualitative comparative analysis

This article explains the variation in policy design processes and the resulting policy-outputs of ‘biopolicies' implemented within the domain of Assisted Reproductive Technology (ART) for eleven European and North-American countries. By applying the method of Qualitative Comparative Analysis, the comparison describes and defines the ‘multiple conjunctural causation' to explain the divergences or similarities of ART policies in Europe and North America. The policy preferences of the actors involved in the relevant ART policy network and the institutional rules characterizing the respective polity need to be considered together in order to explain why different countries adopted similar or different ART policies. In particular, the analysis stresses the influence of party politics, the self-regulation of ART by the physicians, the mobilization of interest groups, the number of institutional arenas involved in the designing process and the nature of decision-making rules (power-sharing versus majority) on the designing processes and the resulting policies. Thus, different policy designs are linked to different designing processes, encompassing four ideal-typical decision-making modes: ‘designing by non-decisions', ‘designing by elites', ‘designing by accommodation' and ‘designing by mobilization and consultation'. These results shed new light on the challenges for developing a policy design theory that could provide a robust framework for describing and explaining policy formulation