Accelerated Alternating Descent Methods for Dykstra-Like Problems

This paper extends recent results by the first author and T. Pock (ICG, TU Graz, Austria) on the acceleration of alternating minimization techniques for quadratic plus nonsmooth objectives depending on two variables. We discuss here the strongly convex situation, and how ‘fast’ methods can be derived by adapting the overrelaxation strategy of Nesterov for projected gradient descent. We also investigate slightly more general alternating descent methods, where several descent steps in each variable are alternatively performed.     

Impact of Collagen Crosslinking on Dislocated Human Shoulder Capsules—Effect on Structural and Mechanical Properties

Classical treatments of shoulder instability are associated with recurrence. To determine whether the modification of the capsule properties may be an alternative procedure, the effect of crosslinking treatment on the structure and mechanical properties of diseased human shoulder capsules was investigated. Joint capsules harvested from patients during shoulder surgery (n = 5) were treated or not with UV and/or riboflavin (0.1%, 1.0% and 2.5%). The structure and the mechanical properties of the capsules were determined by atomic force microscopy. The effect of treatments on cell death was investigated. Collagen fibrils were well-aligned and adjacent to each other with a D-periodicity of 66.9 ± 3.2 nm and a diameter of 71.8 ± 15.4 nm in control untreated capsules. No effect of treatments was observed on the organization of the collagen fibrils nor on their intrinsic characteristics, including D-periodicity or their mean diameter. The treatments also did not induce cell death. In contrast, UV + 2.5% riboflavin induced capsule stiffness, as revealed by the increased Young’s modulus values (p < 0.0001 for each patient). Our results showed that the crosslinking procedure changed the biomechanics of diseased capsules, while keeping their structural organisation unchanged at the single fibril level. The UV/riboflavin crosslinking procedure may be a promising way to preserve the functions of collagen-based tissues and tune their elasticity for clinically relevant treatments.     

Dynamic resource allocation for controlling pathogen spread on a large metapopulation network

To control the spread of an infectious disease over a large network, the optimal allocation by a social planner of a limited resource is a fundamental and difficult problem. We address this problem for a livestock disease that propagates on an animal trade network according to an epidemiological–demographic model based on animal demographics and trade data. We assume that the resource is dynamically allocated following a certain score, up to the limit of resource availability. We adapt a greedy approach to the metapopulation framework, obtaining new scores that minimize approximations of two different objective functions, for two control measures: vaccination and treatment. Through intensive simulations, we compare the greedy scores with several heuristics. Although topology-based scores can limit the spread of the disease, information on herd health status seems crucial to eradicating the disease. In particular, greedy scores are among the most effective in reducing disease prevalence, even though they do not always perform the best. However, some scores may be preferred in real life because they are easier to calculate or because they use a smaller amount of resources. The developed approach could be adapted to other epidemiological models or to other control measures in the metapopulation setting.     

Reduction of Odorous Compounds in Fresh Pig Slurry by Dietary Control of Crude Protein

Two diets containing reduced levels of crude protein for both growing (35–65 kg) and finishing (65–95 kg) pigs were tested against standard commercial diets to determine changes in the odorants produced in fresh slurry. The experimental diets were formulated on a least cost basis using either a full commercial database or with restriction mainly to home-grown (UK) cereals and pulses. Synthetic essential amino acids were included in both formulations to obtain essential amino acids in an ideal protein ratio, with the crude protein being as low as possible. Nitrogen excretion by both growing and finishing pigs offered the low crude protein diets was significantly lower (P<0·001) than that of pigs offered the commercial diets. Major odorants responsible for pig odour from slurries were identified and their concentrations determined using gas chromatography–mass spectrometry. Five out of 10 odorants from slurries produced by growing pigs were significantly lower (P<0·05) in concentration for each of the low crude protein diets compared with the commercial diet. For the finishing pigs, nine out of ten odorants from slurries for the least cost and four odorants for the home grown diets were significantly lower (P<0·05) than slurry produced from the commercial diet. Reducing dietary nitrogen and providing essential amino acids in an ideal protein ratio not only decreases the nitrogen excreted by the pig, but also reduces odorants produced in the resultant slurries.     

Practitioner versus analyst methods: A nuclear decommissioning case study

A requirement arose during decommissioning work at a UK Magnox Nuclear Power Station to identify the hazards involved in removing High Dose Rate Items from a Cartridge Cooling Pond. Removing objects from the cooling pond under normal situations is a routine event with well understood risks but the situation described in this paper is not a routine event. The power station has shifted from an operational phase in its life-cycle to a decommissioning phase, and as such the risks, and procedures to deal with them, have become more novel and uncertain. This raises an important question. Are the hazard identification methods that have proven useful in one phase of the system lifecycle just as useful in another, and if not, what methods should be used? An opportunity arose at this site to put the issue to a direct test. Two methods were used, one practitioner focussed and in widespread use during the plant's operational phase (the Structured What-If method), the other was an analyst method (Cognitive Work Analysis). The former is proven on this site but might not be best suited to the novelty and uncertainty brought about by a shift in context from operations to decommissioning. The latter is not proven on this site but it is designed for novelty and uncertainty. The paper presents the outcomes of applying both methods to a real-world hazard identification task.     

Indigenous relational understandings of the house-as-home: embodied co-becoming with Jerrinja Country

Abstract

The paper considers what housing studies can learn from Indigenous understandings of the house-as-home. Explored through Indigenous ontologies and epistemologies of the house-as-home, the objective of the paper is to offer nuanced understandings of the social and material work of the house itself in the making and unmaking of home. We draw on an Indigenous/non-Indigenous collaborative research, led by Jerrinja elders. The research design included veranda yarning sessions and Indigenous talking circles. Three dimensions emerged strongly from Jerrinja people’s understandings of the making and unmaking of house-as-home: home as an objective capacity, an aesthetic sensibility, and an affective experience of Country. These dimensions are discussed through a relational framework that combines Panelli’s discussion of ‘Country-as-home’, Prout’s idea of ‘kinship-as-home’ and Bissell’s thinking around materiality in achieving comfort. The paper concludes by reflecting on the importance of including Indigenous knowledge if housing studies as a field is to go beyond a Western cultural politics of the house-as-home.     

A missense mutation in PFAS (phosphoribosylformylglycinamidine synthase) is likely causal for embryonic lethality associated with the MH1 haplotype in Montbéliarde dairy cattle

A candidate mutation in the sex hormone binding globulin gene was proposed in 2013 to be responsible for the MH1 recessive embryonic lethal locus segregating in the Montbéliarde breed. In this follow-up study, we excluded this candidate variant because healthy homozygous carriers were observed in large-scale genotyping data generated in the framework of the genomic selection program. We fine mapped the MH1 locus in a 702-kb interval and analyzed genome sequence data from the 1,000 bull genomes project and 54 Montbéliarde bulls (including 14 carriers and 40 noncarriers). We report the identification of a strong candidate mutation in the gene encoding phosphoribosylformylglycinamidine synthase (PFAS), a protein involved in de novo purine synthesis. This mutation, located in a class I glutamine amidotransferase–like domain, results in the substitution of an arginine residue that is entirely conserved among eukaryotes by a cysteine (p.R1205C). No homozygote for the cysteine-encoding allele was observed in a large population of more than 25,000 individuals despite a 6.7% allelic frequency and 122 expected homozygotes under neutrality assumption. Genotyping of 18 embryos collected from heterozygous parents as well as analysis on nonreturn rates suggested that most homozygous carriers died between 7 and 35 d postinsemination. The identification of this strong candidate mutation will enable the accurate testing of the reproducers and the efficient selection against this lethal recessive embryonic defect in the Montbéliarde breed.     

Sperm Chromatin Condensation Defect Accelerates the Kinetics of Early Embryonic Development but Does Not Modify ICSI Outcome

The origin and quality of gametes are likely to influence the kinetics of embryonic development. The purpose of the study was to assess the impact of sperm nuclear quality, and in particular sperm chromatin condensation, on the kinetics of early embryo development after intracytoplasmic sperm injection (ICSI). Our study included 157 couples who benefitted from ICSI for male factor infertility. Chromatin condensation and DNA fragmentation were assessed in spermatozoa prior to ICSI. Above the 20% threshold of sperm condensation defect, patients were included in the abnormal sperm chromatin condensation (ASCC) group; below the 20% threshold, patients were included in the normal sperm chromatin condensation (NSCC) group. After ICSI, the oocytes were placed in the time-lapse incubator. The kinetics of the cohort’s embryonic development have been modeled. The fading times of pronuclei and the time to two blastomeres (t2, first cleavage) and four blastomeres (t4, third cleavage) differed significantly between the NSCC and ASCC groups, with earlier events occurring in the ASCC group. On the other hand, the state of sperm chromatin condensation did not seem to have an impact on live birth rates or the occurrence of miscarriages. The kinetics of early embryonic development was accelerated in males with a sperm chromatin condensation defect without compromising the chances of pregnancy or promoting miscarriage. However, our study highlights the paternal contribution to early embryonic events and potentially to the future health of the conceptus.