A Better Definition of the Kilogram

Fixing the value of Avogadro\u27s constant, the number of atoms in 12 grams of carbon-12, at exactly 844468863 would imply that one gram is the mass of exactly 18x140744813 carbon-12 atoms. This new definition of the gram, and thereby also the kilogram, is precise, elegant and unchanging in time, unlike the current 118-year-old artifact kilogram in Paris and the proposed experimental definitions of the kilogram using man-made silicon spheres or the watt balance apparatus

Hubble\u27s law implies Benford\u27s law for distances to galaxies

A recent article by Alexopoulos and Leontsinis presented empirical evidence that the first digits of the distances from the Earth to galaxies are a reasonably good fit to the probabilities predicted by Benford’s law, the well known logarithmic statistical distribution of significant digits. The purpose of the present article is to give a theoretical explanation, based on Hubble’s law and mathematical properties of Benford’s law, why galaxy distances might be expected to follow Benford’s law. The new galaxy-distance law derived here, which is robust with respect to change of scale and base, to additive and multiplicative computational or observational errors, and to variability of the Hubble constant in both time and space, predicts that conformity to Benford’s law will improve as more data on distances to galaxies becomes available. Conversely, with the logical derivation of this law presented here, the recent empirical observations may be viewed as independent evidence of the validity of Hubble’s law

Extreme Tail Ratios and Overrepresentation among Subpopulations with Normal Distributions

Given several different populations, the relative proportions of each in the high (or low) end of the distribution of a given characteristic are often more important than the overall average values or standard deviations. In the case of two different normally-distributed random variables, as is shown here, one of the (right) tail ratios will not only eventually be greater than 1 from some point on, but will even become infinitely large. More generally, in every finite mixture of different normal distributions, there will always be exactly one of those distributions that is not only overrepresented in the right tail of the mixture but even completely overwhelms all other subpopulations in the rightmost tails. This property (and the analogous result for the left tails), although not unique to normal distributions, is not shared by other common continuous centrally symmetric unimodal distributions, such as Laplace, nor even by other bell-shaped distributions, such as Cauchy (Lorentz) distributions

The Ultraviolet Imaging Telescope: Instrument and Data Characteristics

The Ultraviolet Imaging Telescope (UIT) was flown as part of the Astro observatory on the Space Shuttle Columbia in December 1990 and again on the Space Shuttle Endeavor in March 1995. Ultraviolet (1200-3300 Angstroms) images of a variety of astronomical objects, with a 40 arcmin field of view and a resolution of about 3 arcsec, were recorded on photographic film. The data recorded during the first flight are available to the astronomical community through the National Space Science Data Center (NSSDC); the data recorded during the second flight will soon be available as well. This paper discusses in detail the design, operation, data reduction, and calibration of UIT, providing the user of the data with information for understanding and using the data. It also provides guidelines for analyzing other astronomical imagery made with image intensifiers and photographic film.Comment: 44 pages, LaTeX, AAS preprint style and EPSF macros, accepted by PAS

β-D-N4-hydroxycytidine (NHC) Inhibits SARS-CoV-2 Through Lethal Mutagenesis But Is Also Mutagenic To Mammalian Cells

Mutagenic ribonucleosides can act as broad-based antiviral agents. They are metabolized to the active ribonucleoside triphosphate form and concentrate in the genomes of RNA viruses during viral replication. β-D-N 4-hydroxycytidine (NHC, the initial metabolite of molnupiravir) is more than 100-fold more active than ribavirin or favipiravir against SARS-CoV-2, with antiviral activity correlated to the level of mutagenesis in virion RNA. However, NHC also displays host mutational activity in an animal cell culture assay, consistent with RNA and DNA precursors sharing a common intermediate of a ribonucleoside diphosphate. These results indicate that highly active mutagenic ribonucleosides may hold risk for the host

Tailored Education Increased Capability and Motivation for Fall Prevention in Older People After Hospitalization

Recently hospitalized older people are at risk of falls and face barriers to undertaking fall prevention strategies after they return home from hospital. The authors examined the effects of tailored education delivered by physiotherapists on the knowledge (capability) and the motivation of older people to engage in fall prevention after hospital discharge. Utilizing data gathered from a recent trial, data was analyzed from 390 people who were 60 years and over without impaired cognition (>7/10 abbreviated mental test score) and discharged from three Australian hospitals. Motivation and capability were measured at baseline in the hospital and at 6-months after hospital discharge by blinded assistants using structured surveys. Bivariate analysis using generalized linear modeling explored the impact of education on the capability and motivation. Engagement in fall prevention strategies was entered as an independent variable during analysis to determine associations with capability and motivation. The education significantly improved capability [−0.4, 95% CI (−0.7, −0.2), p < 0.01] and motivation [−0.8, 95% CI (−1.1, −0.5), p < 0.01] compared with social-control at the time of hospital discharge. In contrast, social-control participants gained capability and motivation over the 6-months, and no significant differences were found between groups in capability [0.001, 95% CI (−0.2, 0.2), p = 0.9] and motivation [−0.01, 95% CI (−0.3, 0.3), p = 0.9] at follow-up. Tailored fall prevention education is recommended around hospital discharge. Participants still needed to overcome barriers to falls prevention engagement post hospitalization. Thus, tailored education along with direct clinical services such as physiotherapy and social supports is warranted for older people to avoid falls and regain function following hospitalization

Disruption of the Sarcoglycan–Sarcospan Complex in Vascular Smooth Muscle A Novel Mechanism for Cardiomyopathy and Muscular Dystrophy

AbstractTo investigate mechanisms in the pathogenesis of cardiomyopathy associated with mutations of the dystrophin–glycoprotein complex, we analyzed genetically engineered mice deficient for either α-sarcoglycan (Sgca) or δ-sarcoglycan (Sgcd). We found that only Sgcd null mice developed cardiomyopathy with focal areas of necrosis as the histological hallmark in cardiac and skeletal muscle. Absence of the sarcoglycan–sarcospan (SG-SSPN) complex in skeletal and cardiac membranes was observed in both animal models. Loss of vascular smooth muscle SG-SSPN complex was only detected in Sgcd null mice and associated with irregularities of the coronary vasculature. Administration of a vascular smooth muscle relaxant prevented onset of myocardial necrosis. Our data indicate that disruption of the SG-SSPN complex in vascular smooth muscle perturbs vascular function, which initiates cardiomyopathy and exacerbates muscular dystrophy

Reducing falls in older adults recently discharged from hospital: A systematic review and meta-analysis

Background: Older adults are known to have increased falls rates and functional decline following hospital discharge, with substantial economic healthcare costs. This systematic review aimed to synthesise the evidence for effective falls prevention interventions in older adults recently discharged from hospital. Methods: Literature searches of six databases of quantitative studies conducted from 1990 to June 2017, reporting falls outcomes of falls prevention interventions for community-dwelling older adults discharged from hospital were included. Study quality was assessed using a standardised JBI critical appraisal tool (MAStARI) and data pooled using Rev-Man Review Manager® Results: Sixteen studies (total sample size N= 3,290, from eight countries, mean age 77) comprising 12 interventions met inclusion criteria. We found home hazard modification interventions delivered to those with a previous falls history (1 study), was effective in reducing the number of falls (RR 0.63, 95%CI 0.43, 0.93, Low GRADE evidence). Home exercise interventions (3 studies) significantly increased the proportion of fallers (OR 1.74, 95%CI 1.17, 2.60, Moderate GRADE evidence), and did not significantly reduce falls rate (RR 1.27, 95%CI 0.99, 1.62, Very Low GRADE evidence) or falls injury rate (RR1.16, 95%CI, 0.83,1.63, Low GRADE evidence). Nutritional supplementation for malnourished older adults (1 study) significantly reduced the proportion of fallers (HR 0.41, 95% CI 0.19, 0.86, Low GRADE evidence). Conclusion: The recommended falls prevention interventions for older adults recently discharged from hospital are to provide home hazard minimisation particularly if they have a recent previous falls history and consider nutritional supplementation if they are malnourished