Pfaffian representations of cubic surfaces

Let K be a field of characteristic zero. We describe an algorithm which requires a homogeneous polynomial F of degree three in K[x_0,x_1,x_2,x_3] and a zero A of F in P^3_K and ensures a linear pfaffian representation of V(F) with entries in K[x_0,x_1,x_2,x_3], under mild assumptions on F and A. We use this result to give an explicit construction of (and to prove the existence of) a linear pfaffian representation of V(F), with entries in K'[x_0,x_1,x_2,x_3], being K' an algebraic extension of K of degree at most six. An explicit example of such a construction is given.Comment: 17 pages. Expanded with some remarks. Published with minor corrections in Geom. Dedicat

Restoring Racial Justice

Abstract: Despite important overlapping interests, until recently, few racial justice advocates have embraced restorative justice, and the restorative justice community has largely failed to explicitly address race. Suggesting a convergence of the two movements, this article presents an overview of restorative justice principles, history, and methods. We review the evidence for racial bias in criminal justice and school discipline and then note emerging restorative initiatives to ameliorate historical and contemporary racial inequities. We conclude by touching on gaps and challenges characterizing research and applied work in the field while suggesting strategies to move toward a racially-conscious restorative movement as both an effective alternative to state-imposed punishment and a powerful force for racial justice

Racial Justice, Restorative Justice and Social Transformation

The Social Justice Institute hosts Fania E. Davis, a leading national voice on restorative justice, in a Community Conversation. Fania E. Davis, a leading national voice on restorative justice, will review Restorative Justice fundamentals and explore present-day critical issues at the intersections of restorative justice, racial justice, and healing. Watch the livestream here. Speaker\u27s Bio Dr. Davis is a leading national voice on restorative justice. She is a long-time social justice activist, civil rights trial attorney, writer, restorative justice practitioner, and educator with a PhD in Indigenous Knowledge. Coming of age in Birmingham, Alabama during the social ferment of the civil rights era, the murder of two close childhood friends in the 1963 Sunday School bombing crystallized within her a passionate commitment to social transformation. For the next decades, she was active in the Civil Rights, Black liberation, women\u27s, prisoners\u27, peace, anti-racial violence, economic justice and anti-apartheid movements. Studying with African indigenous healers catalyzed Davis\u27 search for a healing justice, ultimately leading her to serve as founding director of Restorative Justice of Oakland Youth and co-founding board member of the National Association of Community and Restorative Justice. Her numerous honors include the Ubuntu award for service to humanity, the Dennis Maloney Award for excellence in Youth Restorative Justice, the Black Feminist Shapeshifters and Waymakers’ Award, the Tikkun (Repair the World) award, the Ella Jo Baker Human Rights Award, and the Ebony POWER 100 award. The Los Angeles Times named her a New Civil Rights Leader of the 21st Century. Fania, who resides in Oakland, California, writes and speaks internationally on restorative justice, racial justice, truth processes and indigeneity. Among her publications is the Little Book of Race and Restorative Justice: Black Lives, Justice, and U.S. Social Transformation

Racial Justice, Restorative Justice and Social Transformation

The Social Justice Institute hosts Fania E. Davis, a leading national voice on restorative justice, in a Community Conversation. Fania E. Davis, a leading national voice on restorative justice, will review Restorative Justice fundamentals and explore present-day critical issues at the intersections of restorative justice, racial justice, and healing. Watch the livestream here. Speaker\u27s Bio Dr. Davis is a leading national voice on restorative justice. She is a long-time social justice activist, civil rights trial attorney, writer, restorative justice practitioner, and educator with a PhD in Indigenous Knowledge. Coming of age in Birmingham, Alabama during the social ferment of the civil rights era, the murder of two close childhood friends in the 1963 Sunday School bombing crystallized within her a passionate commitment to social transformation. For the next decades, she was active in the Civil Rights, Black liberation, women\u27s, prisoners\u27, peace, anti-racial violence, economic justice and anti-apartheid movements. Studying with African indigenous healers catalyzed Davis\u27 search for a healing justice, ultimately leading her to serve as founding director of Restorative Justice of Oakland Youth and co-founding board member of the National Association of Community and Restorative Justice. Her numerous honors include the Ubuntu award for service to humanity, the Dennis Maloney Award for excellence in Youth Restorative Justice, the Black Feminist Shapeshifters and Waymakers’ Award, the Tikkun (Repair the World) award, the Ella Jo Baker Human Rights Award, and the Ebony POWER 100 award. The Los Angeles Times named her a New Civil Rights Leader of the 21st Century. Fania, who resides in Oakland, California, writes and speaks internationally on restorative justice, racial justice, truth processes and indigeneity. Among her publications is the Little Book of Race and Restorative Justice: Black Lives, Justice, and U.S. Social Transformation

Body-composition changes in the Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy (CALERIE)-2 study: A 2-y randomized controlled trial of calorie restriction in nonobese humans

Background: Calorie restriction (CR) retards aging and increases longevity in many animal models. However, it is unclear whether CR can be implemented in humans without adverse effects on body composition.Objective: We evaluated the effect of a 2-y CR regimen on body composition including the influence of sex and body mass index (BMI; in kg/m2) among participants enrolled in CALERIE-2 (Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy), a multicenter, randomized controlled trial.Design: Participants were 218 nonobese (BMI: 21.9-28.0) adults aged 21-51 y who were randomly assigned to 25% CR (CR, n = 143) or ad libitum control (AL, n = 75) in a 2:1 ratio. Measures at baseline and 12 and 24 mo included body weight, waist circumference, fat mass (FM), fat-free mass (FFM), and appendicular mass by dual-energy X-ray absorptiometry; activity-related energy expenditure (AREE) by doubly labeled water; and dietary protein intake by self-report. Values are expressed as means ± SDs.Results: The CR group achieved 11.9% ± 0.7% CR over 2-y and had significant decreases in weight (-7.6 ± 0.3 compared with 0.4 ± 0.5 kg), waist circumference (-6.2 ± 0.4 compared with 0.9 ± 0.5 cm), FM (-5.4 ± 0.3 compared with 0.5 ± 0.4 kg), and FFM (-2.0 ± 0.2 compared with -0.0 ± 0.2 kg) at 24 mo relative to the AL group (all between-group P < 0.001). Moreover, FFM as a percentage of body weight at 24 mo was higher, and percentage of FM was lower in the CR group than in the AL. AREE, but not protein intake, predicted preservation of FFM during CR (P < 0.01). Men in the CR group lost significantly more trunk fat (P = 0.03) and FFM expressed as a percentage of weight loss (P < 0.001) than women in the CR group.Conclusions: Two years of CR had broadly favorable effects on both whole-body and regional adiposity that could facilitate health span in humans. The decrements in FFM were commensurate with the reduced body mass; although men in the CR group lost more FFM than the women did, the percentage of FFM in the men in the CR group was higher than at baseline. CALERIE was registered at clinicaltrials.gov as NCT00427193

Genomic analysis of sewage from 101 countries reveals global landscape of antimicrobial resistance

Antimicrobial resistance (AMR) is a major threat to global health. Understanding the emergence, evolution, and transmission of individual antibiotic resistance genes (ARGs) is essential to develop sustainable strategies combatting this threat. Here, we use metagenomic sequencing to analyse ARGs in 757 sewage samples from 243 cities in 101 countries, collected from 2016 to 2019. We find regional patterns in resistomes, and these differ between subsets corresponding to drug classes and are partly driven by taxonomic variation. The genetic environments of 49 common ARGs are highly diverse, with most common ARGs carried by multiple distinct genomic contexts globally and sometimes on plasmids. Analysis of flanking sequence revealed ARG-specific patterns of dispersal limitation and global transmission. Our data furthermore suggest certain geographies are more prone to transmission events and should receive additional attention