The association between age at first calving and survival of first lactation heifers within dairy herds

The objective of this research was to evaluate the survival rate of primiparous heifers within a large sample of herds across the UK and specifically to assess the association between age at first calving (AFC) on their survival. Data from 437 herds was re-structured for analysis. Descriptive statistics were calculated, and a multilevel logistic regression model used to explore factors associated with the risk of first lactation culling. Potential explanatory variables included AFC, herd size, culling rate within the whole herd, calving season, herd mean 305d yield and herd mean calving interval. The mean within-herd culling rate for the primiparous heifers was 15.9%. The mean within-herd AFC was 29.6 months, with 35.9% of heifers having an AFC greater than 30 months of age. Multivariable analysis revealed a negative association between survival rate of primiparous heifers and increasing AFC, and also associations with herd culling rate in older cows and calving season. This study highlights the importance of AFC for survival of primiparous heifers, as well the need to address heifer wastage in herds with high culling rates

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

Long Modular Multiplication for Cryptographic Applications

Abstract. A digit-serial, multiplier-accumulator based cryptographic coprocessor architecture is proposed, similar to fix-point DSP's with enhancements, supporting long modular arithmetic and general computations. Several new “column-sum ” variants of popular quadratic time modular multiplication algorithms are presented (Montgomery and interleaved division-reduction with or without Quisquater scaling), which are faster than the traditional implementations, need no or very little memory beyond the operand storage and perform squaring about twice faster than general multiplications or modular reductions. They provide similar advantages in software for general purpose CPU's

Bipartite Modular Multiplication

This paper proposes a new fast method for calculating modular multiplication. The calculation is performed using a new representation of residue classes modulo M that enables the splitting of the multiplier into two parts. These two parts are then processed separately, in parallel, potentially doubling the calculation speed. The upper part and the lower part of the multiplier are processed using the interleaved modular multiplication algorithm and the Montgomery algorithm respectively. Conversions back and forth between the original integer set and the new residue system can be performed at speeds up to twice that of the Montgomery method without the need for precomputed constants. This new method is suitable for both hardware implementation; and software implementation in a multiprocessor environment. Although this paper is focusing on the application of the new method in the integer field, the technique used to speed up the calculation can also easily be adapted for operation in the binary extended field GF (2 m)