Nucleotide bias of DCL and AGO in plant anti-virus gene silencing

Plant Dicer-like (DCL) and Argonaute (AGO) are the key enzymes involved in anti-virus post-transcriptional gene silencing (AV-PTGS). Here we show that AV-PTGS exhibited nucleotide preference by calculating a relative AV-PTGS efficiency on processing viral RNA substrates. In comparison with genome sequences of dicot-infecting Turnip mosaic virus (TuMV) and monocot-infecting Cocksfoot streak virus (CSV), viral-derived small interfering RNAs (vsiRNAs) displayed positive correlations between AV-PTGS efficiency and G+C content (GC%). Further investigations on nucleotide contents revealed that the vsiRNA populations had G-biases. This finding was further supported by our analyses of previously reported vsiRNA populations in diverse plant-virus associations, and AGO associated Arabidopsis endogenous siRNA populations, indicating that plant AGOs operated with G-preference. We further propose a hypothesis that AV-PTGS imposes selection pressure(s) on the evolution of plant viruses. This hypothesis was supported when potyvirus genomes were analysed for evidence of GC elimination, suggesting that plant virus evolution to have low GC% genomes would have a unique function, which is to reduce the host AV-PTGS attack during infections

High-Velocity Features of Calcium and Silicon in the Spectra of Type Ia Supernovae

"High-velocity features" (HVFs) are spectral features in Type Ia supernovae (SNe Ia) that have minima indicating significantly higher (by greater than about 6000 km/s) velocities than typical "photospheric-velocity features" (PVFs). The PVFs are absorption features with minima indicating typical photospheric (i.e., bulk ejecta) velocities (usually ~9000-15,000 km/s near B-band maximum brightness). In this work we undertake the most in-depth study of HVFs ever performed. The dataset used herein consists of 445 low-resolution optical and near-infrared (NIR) spectra (at epochs up to 5 d past maximum brightness) of 210 low-redshift SNe Ia that follow the "Phillips relation." A series of Gaussian functions is fit to the data in order to characterise possible HVFs of Ca II H&K, Si II {\lambda}6355, and the Ca II NIR triplet. The temporal evolution of the velocities and strengths of the PVFs and HVFs of these three spectral features is investigated, as are possible correlations with other SN Ia observables. We find that while HVFs of Ca II are regularly observed (except in underluminous SNe Ia, where they are never found), HVFs of Si II {\lambda}6355 are significantly rarer, and they tend to exist at the earliest epochs and mostly in objects with large photospheric velocities. It is also shown that stronger HVFs of Si II {\lambda}6355 are found in objects that lack C II absorption at early times and that have red ultraviolet/optical colours near maximum brightness. These results lead to a self-consistent connection between the presence and strength of HVFs of Si II {\lambda}6355 and many other mutually correlated SN~Ia observables, including photospheric velocity.Comment: 48 pages (22 of which are tables), 15 figures, 5 tables, re-submitted to MNRAS (after first referee report

Usability and comfort in Canadian offices: Interview of 170 university employees

Increasing building automation to improve energy efficiency introduces a risk of reducing occupants' perceived control and overall comfort. To this end, this paper presents a field study that used contextual techniques to explore the relationship between occupants' perceived control and comfort, as well as their preferences for building automation. A total of 170 occupants in 23 Canadian university campus buildings were interviewed in their offices using semi-structured interviews. All interviews entailed verbally administering a survey while photographs were systematically used to identify the context of occupants' interactions with building controls. Findings revealed that occupants' perception of comfort was moderately correlated to their perception of control over their indoor environment. Occupants also showed an overwhelming preference for more control opportunities in their offices (e.g. operable windows and dimmable lighting controls). Conducting interviews in offices yielded many interesting anecdotes and enabled the researcher to identify contextual issues related to building controls' accessibility, which may have been unnoticed otherwise. The findings of this research contribute to a broader debate within the research community about the appropriate level of building automation to optimize energy efficiency and occupant comfort

HAT-P-50b, HAT-P-51b, HAT-P-52b, and HAT-P-53b: Three Transiting Hot Jupiters and a Transiting Hot Saturn From the HATNet Survey

We report the discovery and characterization of four transiting exoplanets by the HATNet survey. The planet HAT-P-50b has a mass of 1.35 M_J and a radius of 1.29 R_J, and orbits a bright (V = 11.8 mag) M = 1.27 M_sun, R = 1.70 R_sun star every P = 3.1220 days. The planet HAT-P-51b has a mass of 0.31 M_J and a radius of 1.29 R_J, and orbits a V = 13.4 mag, M = 0.98 M_sun, R = 1.04 R_sun star with a period of P = 4.2180 days. The planet HAT-P-52b has a mass of 0.82 M_J and a radius of 1.01 R_J, and orbits a V = 14.1 mag, M = 0.89 M_sun, R = 0.89 R_sun star with a period of P = 2.7536 days. The planet HAT-P-53b has a mass of 1.48 M_J and a radius of 1.32 R_J, and orbits a V = 13.7 mag, M = 1.09 M_sun, R = 1.21 R_sun star with a period of P = 1.9616 days. All four planets are consistent with having circular orbits and have masses and radii measured to better than 10% precision. The low stellar jitter and favorable R_P/R_star ratio for HAT-P-51 make it a promising target for measuring the Rossiter-McLaughlin effect for a Saturn-mass planet.Comment: Submitted to AJ. 20 pages, 9 figures, 5 tables. Data available at http://hatnet.org

Safety-Critical Control of Compartmental Epidemiological Models with Measurement Delays

We introduce a methodology to guarantee safety against the spread of infectious diseases by viewing epidemiological models as control systems and by considering human interventions (such as quarantining or social distancing) as control input. We consider a generalized compartmental model that represents the form of the most popular epidemiological models and we design safety-critical controllers that formally guarantee safe evolution with respect to keeping certain populations of interest under prescribed safe limits. Furthermore, we discuss how measurement delays originated from incubation period and testing delays affect safety and how delays can be compensated via predictor feedback. We demonstrate our results by synthesizing active intervention policies that bound the number of infections, hospitalizations and deaths for epidemiological models capturing the spread of COVID-19 in the USA.Comment: Submitted to the IEEE Control System Letters (L-CSS) and the 2021 American Control Conference (ACC). 6 pages, 3 figure

Evaluation of ADAM-12 as a diagnostic biomarker of ectopic pregnancy in women with a pregnancy of unknown location

Ectopic pregnancy (EP) remains the most life-threatening acute condition in modern gynaecology. It remains difficult to diagnose early and accurately. Women often present at emergency departments in early pregnancy with a 'pregnancy of unknown location' (PUL) and diagnosis/exclusion of EP is challenging due to a lack of reliable biomarkers. Recent studies suggest that serum levels of a disintegrin and metalloprotease protein-12 (ADAM-12) can be used differentiate EP from viable intrauterine pregnancy (VIUP). Here we describe a prospective study evaluating the performance of ADAM-12 in differentiating EP from the full spectrum of alternative PUL outcomes in an independent patient cohort.Sera were collected from 120 patients at their first clinical presentation with a PUL and assayed for ADAM-12 by ELISA. Patients were categorized according to final pregnancy outcomes. Serum ADAM-12 concentrations were increased in women with histologically-confirmed EP (median 442 pg/mL; 25%-75% percentile 232-783 pg/mL) compared to women with VIUP (256 pg/mL; 168-442 pg/mL) or miscarriage (192 pg/mL; 133-476 pg/mL). Serum ADAM-12 did not differentiate histologically-confirmed EP from spontaneously resolving PUL (srPUL) (416 pg/mL; 154-608 pg/mL). The diagnostic potential of ADAM-12 was only significant when 'ambiguous' PUL outcomes were excluded from the analysis (AROC = 0.6633; P = 0.03901).When measured in isolation, ADAM-12 levels had limited value as a diagnostic biomarker for EP in our patient cohort. The development of a reliable serum biomarker-based test for EP remains an ongoing challenge

Globular glial tauopathy type II

The globular glial tauopathies (GGTs) are a rare group of neurodegenerative diseases with fewer than 90 autopsy-confirmed cases reported in the literature. Although there has been some uncertainty about whether GGT is entirely distinct from progressive supranuclear palsy, a recent study of tau filament structures supports the definition of GGT as a separate neuropathological entity. We present a sporadic case of GGT type II presenting with a progressive corticobasal-primary lateral sclerosis overlap syndrome in a 74-year-old woman. Neuropathological examination identified neuronal and glial tau inclusions, including globular astrocytic and oligodendroglial inclusions. We also discuss the clinical features and molecular pathophysiology of GGT. Increased awareness of this condition could become more important as patients with GGT may be candidates for anti-tau therapies currently undergoing clinical evaluation in patients with other tauopathies