117 research outputs found
Entanglement of two qubits in a relativistic orbit
The creation and destruction of entanglement between a pair of interacting
two-level detectors accelerating about diametrically opposite points of a
circular path is investigated. It is found that any non-zero acceleration has
the effect of suppressing the vacuum entanglement and enhancing the
acceleration radiation thereby reducing the entangling capacity of the
detectors. Given that for large accelerations the acceleration radiation is the
dominant effect, we investigate the evolution of a two detector system
initially prepared in a Bell state using a perturbative mater equation and
treating the vacuum fluctuations as an unobserved environment. A general
function for the concurrence is obtained for stationary and symmetric
worldlines in flatspace. The entanglement sudden death time is computed.Comment: v2: Some typo's fixed, figures compressed to smaller filesize and
added some references
On-Sky Demonstration of a Linear Band-limited Mask with Application to Visual Binary Stars
We have designed and built the first band-limited coronagraphic mask used for
ground-based high-contrast imaging observations. The mask resides in the focal
plane of the near-infrared camera PHARO at the Palomar Hale telescope and
receives a well-corrected beam from an extreme adaptive optics system. Its
performance on-sky with single stars is comparable to current state-of-the-art
instruments: contrast levels of or better at 0.8" in after
post-processing, depending on how well non-common-path errors are calibrated.
However, given the mask's linear geometry, we are able to conduct additional
unique science observations. Since the mask does not suffer from pointing
errors down its long axis, it can suppress the light from two different stars
simultaneously, such as the individual components of a spatially resolved
binary star system, and search for faint tertiary companions. In this paper, we
present the design of the mask, the science motivation for targeting binary
stars, and our preliminary results, including the detection of a candidate
M-dwarf tertiary companion orbiting the visual binary star HIP 48337, which we
are continuing to monitor with astrometry to determine its association.Comment: Accepted to Ap
Defining causality in COVID-19 and neurological disorders.
When faced with acute neurological presentations in a patient with COVID-19,
how confident can one be that SARS-CoV2 is causal
Spectrum, risk factors and outcomes of neurological and psychiatric complications of COVID-19: a UK-wide cross-sectional surveillance study.
SARS-CoV-2 is associated with new-onset neurological and psychiatric conditions. Detailed clinical data, including factors associated with recovery, are lacking, hampering prediction modelling and targeted therapeutic interventions. In a UK-wide cross-sectional surveillance study of adult hospitalized patients during the first COVID-19 wave, with multi-professional input from general and sub-specialty neurologists, psychiatrists, stroke physicians, and intensivists, we captured detailed data on demographics, risk factors, pre-COVID-19 Rockwood frailty score, comorbidities, neurological presentation and outcome. A priori clinical case definitions were used, with cross-specialty independent adjudication for discrepant cases. Multivariable logistic regression was performed using demographic and clinical variables, to determine the factors associated with outcome. A total of 267 cases were included. Cerebrovascular events were most frequently reported (131, 49%), followed by other central disorders (95, 36%) including delirium (28, 11%), central inflammatory (25, 9%), psychiatric (25, 9%), and other encephalopathies (17, 7%), including a severe encephalopathy (n = 13) not meeting delirium criteria; and peripheral nerve disorders (41, 15%). Those with the severe encephalopathy, in comparison to delirium, were younger, had higher rates of admission to intensive care and a longer duration of ventilation. Compared to normative data during the equivalent time period prior to the pandemic, cases of stroke in association with COVID-19 were younger and had a greater number of conventional, modifiable cerebrovascular risk factors. Twenty-seven per cent of strokes occurred in patients 60 years old, the younger stroke patients presented with delayed onset from respiratory symptoms, higher rates of multi-vessel occlusion (31%) and systemic thrombotic events. Clinical outcomes varied between disease groups, with cerebrovascular disease conferring the worst prognosis, but this effect was less marked than the pre-morbid factors of older age and a higher pre-COVID-19 frailty score, and a high admission white cell count, which were independently associated with a poor outcome. In summary, this study describes the spectrum of neurological and psychiatric conditions associated with COVID-19. In addition, we identify a severe COVID-19 encephalopathy atypical for delirium, and a phenotype of COVID-19 associated stroke in younger adults with a tendency for multiple infarcts and systemic thromboses. These clinical data will be useful to inform mechanistic studies and stratification of patients in clinical trials
The view from everywhere: Disciplining diversity in post–World War II international social science
This paper explores the attempt of social scientists associated with Unesco to create a system of knowledge production to provide the international perspective necessary for democratic governance of a world community. Social scientists constructed a federal system of international associations that institutionalized American disciplines on an international scale. An international perspective emerged through the process of interdisciplinary international research. I call this ideal of coordinating multiple subjectivities to produce objectivity the “view from everywhere.” Influenced by social psychological “action-research,” collaborative research was group therapy. The attempt to operationalize internationalists' rallying slogan, “unity in diversity,” illuminated tensions inherent in the mobilization of science for social and political reform. © 2009 Wiley Periodicals, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/64294/1/20394_ftp.pd
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
Assemblathon 2: evaluating de novo methods of genome assembly in three vertebrate species
Background: The process of generating raw genome sequence data continues to become cheaper, faster, and more accurate. However, assembly of such data into high-quality, finished genome sequences remains challenging. Many genome assembly tools are available, but they differ greatly in terms of their performance (speed, scalability, hardware requirements, acceptance of newer read technologies) and in their final output (composition of assembled sequence). More importantly, it remains largely unclear how to best assess the quality of assembled genome sequences. The Assemblathon competitions are intended to assess current state-of-the-art methods in genome assembly. Results: In Assemblathon 2, we provided a variety of sequence data to be assembled for three vertebrate species (a bird, a fish, and snake). This resulted in a total of 43 submitted assemblies from 21 participating teams. We evaluated these assemblies using a combination of optical map data, Fosmid sequences, and several statistical methods. From over 100 different metrics, we chose ten key measures by which to assess the overall quality of the assemblies. Conclusions: Many current genome assemblers produced useful assemblies, containing a significant representation of their genes and overall genome structure. However, the high degree of variability between the entries suggests that there is still much room for improvement in the field of genome assembly and that approaches which work well in assembling the genome of one species may not necessarily work well for another
Artificial cell research as a field that connects chemical, biological and philosophical questions
This review article discusses the interdisciplinary nature and implications of artificial cell research. It starts from two historical theories: Gánti's chemoton model and the autopoiesis theory by Maturana and Varela. They both explain the transition from chemical molecules to biological cells. These models exemplify two different ways in which disciplines of chemistry, biology and philosophy can profit from each other. In the chemoton model, conclusions from one disciplinary approach are relevant for the other disciplines. In contrast, the autopoiesis model itself (rather than its conclusions) is transferred from one discipline to the other. The article closes by underpinning the relevance of artificial cell research for philosophy with reference to the on-going philosophical debates on emergence, biological functions and biocentrism
Health outcomes 3 months and 6 months after molnupiravir treatment for COVID-19 for people at higher risk in the community (PANORAMIC): a randomised controlled trial
Background:
No randomised controlled trials have yet reported on the effectiveness of molnupiravir on longer term outcomes for COVID-19. The PANORAMIC trial found molnupiravir reduced time to recovery in acute COVID-19 over 28 days. We aimed to report the effect of molnupiravir treatment for COVID-19 on wellbeing, severe and persistent symptoms, new infections, health care and social service use, medication use, and time off work at 3 months and 6 months post-randomisation.
Methods:
This study is a follow-up to the main analysis, which was based on the first 28 days of follow-up and has been previously reported. For this multicentre, primary care, open-label, multi-arm, prospective randomised controlled trial conducted in the UK, participants were eligible if aged at least 50 years, or at least 18 years with a comorbidity, and unwell 5 days or less with confirmed COVID-19 in the community. Participants were randomly assigned to the usual care group or molnupiravir group plus usual care (800 mg twice a day for 5 days), which was stratified by age (<50 years or ≥50 years) and vaccination status (at least one dose: yes or no). The primary outcome was hospitalisation or death (or both) at 28 days; all longer term outcomes were considered to be secondary outcomes and included self-reported ratings of wellness (on a scale of 0–10), experiencing any symptom (fever, cough, shortness of breath, fatigue, muscle ache, nausea and vomiting, diarrhoea, loss of smell or taste, headache, dizziness, abdominal pain, and generally feeling unwell) rated as severe (moderately bad or major problem) or persistent, any health and social care use, health-related quality of life (measured by the EQ-5D-5L), time off work or school, new infections, and hospitalisation.
Findings:
Between Dec 8, 2021, and April 27, 2022, 25 783 participants were randomly assigned to the molnupiravir plus usual care group (n=12 821) or usual care group (n=12 962). Long-term follow-up data were available for 23 008 (89·2%) of 25 784 participants with 11 778 (91·9%) of 12 821 participants in the molnupiravir plus usual care group and 11 230 (86·6%) of 12 963 in the usual care group. 22 806 (99·1%) of 23 008 had at least one previous dose of a SARS-CoV-2 vaccine. Any severe (3 months: adjusted risk difference –1·6% [–2·6% to –0·6%]; probability superiority [p(sup)]>0·99; number needed to treat [NNT] 62·5; 6 months: –1·9% [–2·9% to –0·9%]; p(sup)>0·99, NNT 52·6) or persistent symptoms (3 months: adjusted risk difference –2·1% [–2·9% to –1·5%]; p(sup)>0·99; NNT 47·6; 6 months: –2·5% [–3·3% to –1·6%]; p(sup)>0·99; NNT 40) were reduced in severity, and health-related quality of life (measured by the EQ-5D-5L) improved in the molnupiravir plus usual care group at 3 months and 6 months (3 months: adjusted mean difference 1·08 [0·65 to 1·53]; p(sup)>0·99; 6 months: 1·09 [0·63 to 1·55]; p(sup)>0·99). Ratings of wellness (3 months: adjusted mean difference 0·15 (0·11 to 0·19); p(sup)>0·99; 6 months: 0·12 (0·07 to 0·16); p(sup)>0·99), experiencing any more severe symptom (3 months; adjusted risk difference –1·6% [–2·6% to –0·6%]; p(sup)=0·99; 6 months: –1·9% [–2·9% to –0·9%]; p(sup)>0·99), and health-care use (3 months: adjusted risk difference –1·4% [–2·3% to –0·4%]; p(sup)>0·99; NNT 71·4; 6 months: –0·5% [–1·5% to 0·4%]; p(sup)>0·99; NNT 200) had high probabilities of superiority with molnupiravir treatment. There were significant differences in persistence of any symptom (910 [8·9%] of 10 190 vs 1027 [11%] of 9332, NNT 67) at 6 months, and reported time off work at 3 months (2017 [17·9%] of 11 274 vs 2385 [22·4%] of 10 628) and 6 months (460 [4·4%] of 10 562 vs 527 [5·4%] of 9846; NNT 100). There were no differences in hospitalisations at long-term follow-up.
Interpretation:
In a vaccinated population, people treated with molnupiravir for acute COVID-19 felt better, experienced fewer and less severe COVID-19 associated symptoms, accessed health care less often, and took less time off work at 6 months. However, the absolute differences in this open-label design are small with high numbers needed to treat
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