Generation and control of non-local quantum equivalent extreme ultraviolet photons

We present a high precision, self-referencing, common path XUV interferometer setup to produce pairs of spatially separated and independently controllable XUV pulses that are locked in phase and time. The spatial separation is created by introducing two equal but opposite wavefront tilts or using superpositions of orbital angular momentum. In our approach, we can independently control the relative phase/delay of the two optical beams with a resolution of 52 zs (zs = zeptoseconds). In order to explore the level of entanglement between the non-local photons, we compare three different beam modes: Bessel-like, and Gaussian with or without added orbital angular momentum. By reconstructing interference patterns one or two photons at a time we conclude that the beams are not entangled, yet each photon in the attosecond pulse train contains information about the entire spectrum. Our technique generates non-local, quantum equivalent XUV photons with a temporal jitter of 3 zs, just below the Compton unit of time of 8 zs. We argue that this new level of temporal precision will open the door for new dynamical QED tests. We also discuss the potential impact on other areas, such as imaging, measurements of non-locality, and molecular quantum tomography.Comment: 11 pages 5 figures and supplemental materials with 12 pages and 7 figure

Inducible stem cell-derived embryos capture mouse morphogenetic events in vitro

The development of mouse embryos can be partially recapitulated by combining embryonic (ES), trophoblast (TS) and extra-embryonic endoderm (XEN) stem cells to generate ETX-embryos. Although ETX-embryos transcriptionally capture the mouse gastrula, their ability to recapitulate complex morphogenic events such as gastrulation is limited, possibly due to the limited potential of XEN cells. To address this, we generated ES cells transiently expressing transcription factor Gata4 that drives the extra-embryonic endoderm fate and combined them together with ES cells and TS cells to generate induced ETX-embryos (iETX-embryos). We show that iETX-embryos establish a robust anterior signalling centre that migrates unilaterally to break embryo symmetry. Furthermore, iETX-embryos gastrulate generating embryonic and extra-embryonic mesoderm, and definitive endoderm. Our findings reveal that replacement of XEN cells with ES cells transiently expressing Gata4 endows iETX-embryos with greater developmental potential, thus enabling the study of the establishment of anterior-posterior patterning and gastrulation in an in vitro system.This work was supported by a European Research Council Grant (RG77946)Wellcome Trust (207415/Z/17/Z), Open Philanthropy, Shurl and Kay Curci, and Weston Havens Foundations grants awarded to M.Z.G.; K.Y.C.L. is supported by the Croucher Foundation and Cambridge Trust. F.H. is supported by a European Research Council Grant (695669) and Wellcome Trust (WT108438/C/15/Z). J.D.J. is supported by the Biotechnology and Biological Sciences Research Council

Inducible stem cell-derived embryos capture mouse morphogenetic events in vitro

The development of mouse embryos can be partially recapitulated by combining embryonic (ES), trophoblast (TS) and extra-embryonic endoderm (XEN) stem cells to generate ETX-embryos. Although ETX-embryos transcriptionally capture the mouse gastrula, their ability to recapitulate complex morphogenic events such as gastrulation is limited, possibly due to the limited potential of XEN cells. To address this, we generated ES cells transiently expressing transcription factor Gata4 that drives the extra-embryonic endoderm fate and combined them together with ES cells and TS cells to generate induced ETX-embryos (iETX-embryos). We show that iETX-embryos establish a robust anterior signalling centre that migrates unilaterally to break embryo symmetry. Furthermore, iETX-embryos gastrulate generating embryonic and extra-embryonic mesoderm, and definitive endoderm. Our findings reveal that replacement of XEN cells with ES cells transiently expressing Gata4 endows iETX-embryos with greater developmental potential, thus enabling the study of the establishment of anterior-posterior patterning and gastrulation in an in vitro system.This work was supported by a European Research Council Grant (RG77946)Wellcome Trust (207415/Z/17/Z), Open Philanthropy, Shurl and Kay Curci, and Weston Havens Foundations grants awarded to M.Z.G.; K.Y.C.L. is supported by the Croucher Foundation and Cambridge Trust. F.H. is supported by a European Research Council Grant (695669) and Wellcome Trust (WT108438/C/15/Z). J.D.J. is supported by the Biotechnology and Biological Sciences Research Council

Periodicities in an active region correlated with Type III radio bursts observed by Parker Solar Probe

Context. Periodicities have frequently been reported across many wavelengths in the solar corona. Correlated periods of ~5 minutes, comparable to solar p-modes, are suggestive of coupling between the photosphere and the corona. Aims. Our study investigates whether there are correlations in the periodic behavior of Type III radio bursts, indicative of non-thermal electron acceleration processes, and coronal EUV emission, assessing heating and cooling, in an active region when there are no large flares. Methods. We use coordinated observations of Type III radio bursts from the FIELDS instrument on Parker Solar Probe (PSP), of extreme ultraviolet emissions by the Solar Dynamics Observatory (SDO)/AIA and white light observations by SDO/HMI, and of solar flare x-rays by Nuclear Spectroscopic Telescope Array (NuSTAR) on April 12, 2019. Several methods for assessing periodicities are utilized and compared to validate periods obtained. Results. Periodicities of about 5 minutes in the EUV in several areas of an active region are well correlated with the repetition rate of the Type III radio bursts observed on both PSP and Wind. Detrended 211A and 171A light curves show periodic profiles in multiple locations, with 171A peaks lagging those seen in 211A. This is suggestive of impulsive events that result in heating and then cooling in the lower corona. NuSTAR x-rays provide evidence for at least one microflare during the interval of Type III bursts, but there is not a one-to-one correspondence between the x-rays and the Type-III bursts. Our study provides evidence for periodic acceleration of non-thermal electrons (required to generate Type III radio bursts) when there were no observable flares either in the x-ray data or the EUV. The acceleration process, therefore, must be associated with small impulsive events, perhaps nanoflares

Aortic valve opening and closure: the clover dynamics.

Background: Systolic aortic root expansion is reported to facilitate valve opening, but the precise dynamics remain unknown. A sonometric study with a high data sampling rate (200 to 800 Hz) was conducted in an acute ovine model to better understand the timing, mechanisms, and shape of aortic valve opening and closure. Methods: Eighteen piezoelectric crystals were implanted in 8 sheep at each annular base, commissures, sinus of Valsalva, sinotubular junction, nodulus of Arantius, and ascending aorta (AA). Geometric changes were time related to pressures and flows. Results: The aortic root was hemodynamically divided into left ventricular (LV) and aortic compartments situated, respectively, below and above the leaflets. During isovolumetric contraction (IVC), aortic root expansion started in the LV compartment, most likely due to volume redistribution in the LV outflow tract below the leaflets. This expansion initiated leaflet separation prior to ejection (2.1%±0.5% of total opening area). Aortic compartment expansion was delayed toward the end of IVC, likely related to volume redistribution above the leaflets due to accelerating aortic backflow toward the aortic valve and coronary flow reduction due to myocardial contraction. Maximum valve opening during the first third of ejection acquired a truncated cone shape [leaflet free edge area smaller than annular base area (-41.5%±5.5%)]. The distal orifice became clover shaped because the leaflet free edge area is larger than the commissural area by 16.3%±2.0%. Conclusions: Aortic valve opening is initiated prior to ejection related to delicate balance between LV, aortic root, and coronary dynamics. It is clover shaped at maximum opening in systole. A better understanding of these mechanisms should stimulate more physiological surgical approaches of valve repair and replacement

Gravitational waves: search results, data analysis and parameter estimation

The Amaldi 10 Parallel Session C2 on gravitational wave (GW) search results, data analysis and parameter estimation included three lively sessions of lectures by 13 presenters, and 34 posters. The talks and posters covered a huge range of material, including results and analysis techniques for ground-based GW detectors, targeting anticipated signals from different astrophysical sources: compact binary inspiral, merger and ringdown; GW bursts from intermediate mass binary black hole mergers, cosmic string cusps, core-collapse supernovae, and other unmodeled sources; continuous waves from spinning neutron stars; and a stochastic GW background. There was considerable emphasis on Bayesian techniques for estimating the parameters of coalescing compact binary systems from the gravitational waveforms extracted from the data from the advanced detector network. This included methods to distinguish deviations of the signals from what is expected in the context of General Relativity

A questionnaire-based (UM-PDHQ) study of hallucinations in Parkinson's disease

Background: Hallucinations occur in 20-40% of PD patients and have been associated with unfavorable clinical outcomes (i.e., nursing home placement, increased mortality). Hallucinations, like other non-motor features of PD, are not well recognized in routine primary/secondary clinical practice. So far, there has been no instrument for uniform characterization of hallucinations in PD. To this end, we developed the University of Miami Parkinson's disease Hallucinations Questionnaire (UM-PDHQ) that allows comprehensive assessment of hallucinations in clinical or research settings.Methods: The UM-PDHQ is composed of 6 quantitative and 14 qualitative items. For our study PD patients of all ages and in all stages of the disease were recruited over an 18-month period. The UPDRS, MMSE, and Beck Depression and Anxiety Inventories were used for comparisons.Results and Discussion: Seventy consecutive PD patients were included in the analyses. Thirty-one (44.3%) were classified as hallucinators and 39 as non-hallucinators. No significant group differences were observed in terms of demographics, disease characteristics, stage, education, depressive/anxiety scores or cognitive functioning (MMSE) between hallucinators and non-hallucinators. Single mode hallucinations were reported in 20/31 (visual/14, auditory/4, olfactory/2) whereas multiple modalities were reported in 11/31 patients. The most common hallucinatory experience was a whole person followed by small animals, insects and reptiles.Conclusion: Using the UM-PDHQ, we were able to define the key characteristics of hallucinations in PD in our cohort. Future directions include the validation of the quantitative part of the questionnaire than will serve as a rating scale for severity of hallucinations