Nonlinear excitations in CsNiF3 in magnetic fields perpendicular to the easy plane

Experimental and numerical studies of the magnetic field dependence of the specific heat and magnetization of single crystals of CsNiF3 have been performed at 2.4 K, 2.9 K, and 4.2 K in magnetic fields up to 9 T oriented perpendicular to the easy plane. The experimental results confirm the presence of the theoretically predicted double peak structure in the specific heat arising from the formation of nonlinear spin modes. The demagnetizing effects are found to be negligible, and the overall agreement between the data and numerical predictions is better than reported for the case when the magnetic field was oriented in the easy plane. Demagnetizing effects might play a role in generating the difference observed between theory and experiment in previous work analyzing the excess specific heat using the sine-Gordon model.Comment: 6 pages, 5 figures, submitted to Phys. Rev.

Para-infectious brain injury in COVID-19 persists at follow-up despite attenuated cytokine and autoantibody responses

To understand neurological complications of COVID-19 better both acutely and for recovery, we measured markers of brain injury, inflammatory mediators, and autoantibodies in 203 hospitalised participants; 111 with acute sera (1–11 days post-admission) and 92 convalescent sera (56 with COVID-19-associated neurological diagnoses). Here we show that compared to 60 uninfected controls, tTau, GFAP, NfL, and UCH-L1 are increased with COVID-19 infection at acute timepoints and NfL and GFAP are significantly higher in participants with neurological complications. Inflammatory mediators (IL-6, IL-12p40, HGF, M-CSF, CCL2, and IL-1RA) are associated with both altered consciousness and markers of brain injury. Autoantibodies are more common in COVID-19 than controls and some (including against MYL7, UCH-L1, and GRIN3B) are more frequent with altered consciousness. Additionally, convalescent participants with neurological complications show elevated GFAP and NfL, unrelated to attenuated systemic inflammatory mediators and to autoantibody responses. Overall, neurological complications of COVID-19 are associated with evidence of neuroglial injury in both acute and late disease and these correlate with dysregulated innate and adaptive immune responses acutely

Highly-parallelized simulation of a pixelated LArTPC on a GPU

The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we present the first implementation of a full microphysical simulator of a liquid argon time projection chamber (LArTPC) equipped with light readout and pixelated charge readout, developed for the DUNE Near Detector. The software is implemented with an end-to-end set of GPU-optimized algorithms. The algorithms have been written in Python and translated into CUDA kernels using Numba, a just-in-time compiler for a subset of Python and NumPy instructions. The GPU implementation achieves a speed up of four orders of magnitude compared with the equivalent CPU version. The simulation of the current induced on 10^3 pixels takes around 1 ms on the GPU, compared with approximately 10 s on the CPU. The results of the simulation are compared against data from a pixel-readout LArTPC prototype

Large-scale phenotyping of patients with long COVID post-hospitalization reveals mechanistic subtypes of disease

One in ten severe acute respiratory syndrome coronavirus 2 infections result in prolonged symptoms termed long coronavirus disease (COVID), yet disease phenotypes and mechanisms are poorly understood1. Here we profiled 368 plasma proteins in 657 participants ≥3 months following hospitalization. Of these, 426 had at least one long COVID symptom and 233 had fully recovered. Elevated markers of myeloid inflammation and complement activation were associated with long COVID. IL-1R2, MATN2 and COLEC12 were associated with cardiorespiratory symptoms, fatigue and anxiety/depression; MATN2, CSF3 and C1QA were elevated in gastrointestinal symptoms and C1QA was elevated in cognitive impairment. Additional markers of alterations in nerve tissue repair (SPON-1 and NFASC) were elevated in those with cognitive impairment and SCG3, suggestive of brain–gut axis disturbance, was elevated in gastrointestinal symptoms. Severe acute respiratory syndrome coronavirus 2-specific immunoglobulin G (IgG) was persistently elevated in some individuals with long COVID, but virus was not detected in sputum. Analysis of inflammatory markers in nasal fluids showed no association with symptoms. Our study aimed to understand inflammatory processes that underlie long COVID and was not designed for biomarker discovery. Our findings suggest that specific inflammatory pathways related to tissue damage are implicated in subtypes of long COVID, which might be targeted in future therapeutic trials

A MODEL OF BUBBLE GROWTH IN THE KEWB REACTOR

Short-period transients (less than 15 msec) in the KEWB reactor are apparently controlled primarily by void production resulting from gas evolution in the core. A growth mechanism probably prevails during the short-period excursions which differs from that which occurs at longer periods. Experimental data were examined which showed that the energy transferred to the average bubble is an order of magnitude less than that required to cause bubble growth. It is believed, however, that the validity of the growth model can be established by refinements concerning energy availability deposited in the bubble area and by refinement of bubble-size distribution functions. (J.R.D.

Oxygen isotope geochemistry of lavas from an oceanic to continental arc transition, Kermadec-Hikurangi margin, SW Pacific

no abstrac

Palaeolithic investigations at Klithi: preliminary results of the 1984 1985 field seasons

Field-work in 1984 and 1985 centred on the Klithi rockshelter has combined excavation and analysis of finds with palaeoenvironmental and palaeogeographical studies of the wider regional setting. Radiocarbon dates show that the deposits so far excavated extend from 10,000 BP to 17,000 BP. Excavations have concentrated on the uppermost levels (10,000 BP to 12,500 BP) immediately accessible below the surface, in order to develop methods for investigating spatial variation in the distribution of materials in the deposit. They have revealed a large hearth area in the back of the shelter as a major focus of activity. New details of the flint industry and faunal remains are presented, along with preliminary indications of spatial patterning. There is evidence for the performance of a wide range of subsistence activities based on locally available resources as well as evidence, in the form of exotic flint and marine shells, for contacts over a wide area. Palaeogeographical methods of analysis based on field mapping of geology, relief and terrain have been developed to define the distribution and density of the main herbivores under Pleniglacial conditions. Both the evidence from excavation and from these wider palaeogeographical studies emphasize the small scale of human activities, the small size of residential groups, and the likelihood of seasonal movements and social contacts over very extensive territories during the Upper Palaeolithic perio