A White Paper on keV sterile neutrino Dark Matter

We present a comprehensive review of keV-scale sterile neutrino Dark Matter, collecting views and insights from all disciplines involved—cosmology, astrophysics, nuclear, and particle physics—in each case viewed from both theoretical and experimental/observational perspectives. After reviewing the role of active neutrinos in particle physics, astrophysics, and cosmology, we focus on sterile neutrinos in the context of the Dark Matter puzzle. Here, we first review the physics motivation for sterile neutrino Dark Matter, based on challenges and tensions in purely cold Dark Matter scenarios. We then round out the discussion by critically summarizing all known constraints on sterile neutrino Dark Matter arising from astrophysical observations, laboratory experiments, and theoretical considerations. In this context, we provide a balanced discourse on the possibly positive signal from X-ray observations. Another focus of the paper concerns the construction of particle physics models, aiming to explain how sterile neutrinos of keV-scale masses could arise in concrete settings beyond the Standard Model of elementary particle physics. The paper ends with an extensive review of current and future astrophysical and laboratory searches, highlighting new ideas and their experimental challenges, as well as future perspectives for the discovery of sterile neutrinos

A White Paper on keV Sterile Neutrino Dark Matter

We present a comprehensive review of keV-scale sterile neutrino Dark Matter,collecting views and insights from all disciplines involved - cosmology,astrophysics, nuclear, and particle physics - in each case viewed from boththeoretical and experimental/observational perspectives. After reviewing therole of active neutrinos in particle physics, astrophysics, and cosmology, wefocus on sterile neutrinos in the context of the Dark Matter puzzle. Here, wefirst review the physics motivation for sterile neutrino Dark Matter, based onchallenges and tensions in purely cold Dark Matter scenarios. We then round outthe discussion by critically summarizing all known constraints on sterileneutrino Dark Matter arising from astrophysical observations, laboratoryexperiments, and theoretical considerations. In this context, we provide abalanced discourse on the possibly positive signal from X-ray observations.Another focus of the paper concerns the construction of particle physicsmodels, aiming to explain how sterile neutrinos of keV-scale masses could arisein concrete settings beyond the Standard Model of elementary particle physics.The paper ends with an extensive review of current and future astrophysical andlaboratory searches, highlighting new ideas and their experimental challenges,as well as future perspectives for the discovery of sterile neutrinos

Morphometric and immunohistochemical study of the omasum of red deer during prenatal development

The red deer is an important study species because of its value in the national economy and because it provides a wealth of genetic material. To date, there has been little research into the prenatal development of the stomach of ruminants, and none of the red deer. We therefore performed a histological evaluation of the ontogenesis of the omasum in the red deer. Histomorphometric and immunohistochemical analyses were carried out on 50 embryos and fetuses of deer from the initial stages of prenatal life until birth. For test purposes, the animals were divided into five experimental groups: Group I (1.4–3.6 cm crown–rump length, CRL; 30–60 days, 1–25% of gestation); Group II (4.5–7.2 cm CRL; 67–90 days, 25–35% of gestation); Group III (8–19 cm CRL; 97–135 days, 35–50% of gestation); Group IV (21–33 cm CRL; 142–191 days, 50–70% of gestation); and Group V (36–40 cm CRL; 205–235 days, 75–100% of gestation). At 67 embryonic days, the omasum wall was differentiated, and comprised three layers: the epithelial layer, pluripotential blastemic tissue and serosa. The stratification of the epithelial layer was accompanied by changes in its structure, with the appearance of four laminae of different sizes; in order of appearance these were: primary at 67 days, secondary at 90 days, tertiary at 97 days and quaternary at 135 days. At around mid-gestation, lateral evaginations were formed from the stratum basale of the primary and secondary smaller laminae. These were the primitive corneum papillae. From 205 days, the corneum papillae were present in all four sizes of laminae. The histodifferentiation of the lamina propia-submucosa, tunica muscularis and serosa showed patterns of development similar to those reported for the rumen and reticulum of red deer. The omasum of red deer during prenatal life, especially from 67 days of gestation, was shown to be an active structure with full secretory capacity. Its histological development, its secretory capacity (detected by the presence of neutral mucopolysaccharides) and its neuroendocrine nature (detected by the presence of positive non-neuronal enolase cells and the neuropeptides vasoactive intestinal peptide and neuropeptide Y) were parallel to the development of the rumen and the reticulum. However, its prenatal development was later than that of the omasum in sheep, goat and cow

Early growth according to protein content of infant formula: Results from the EDEN

International audienceBACKGROUND: In several systematic reviews, rapid weight gain in early life has been related to increased risk of later obesity. In line with this finding, the "early protein hypothesis" suggests that reducing early protein intake is a potential lever for obesity prevention. OBJECTIVE: To determine whether the variability of protein content of infant formula used in France over the period 2003-2012 is significantly associated with early growth in children. METHODS: A pooled sample of infants from the EDEN (Etude des Determinants pre et postnatals de la sante et du developpement de l'Enfant) mother-child cohort (born in 2003-2006) and the ELFE (Etude Longitudinale Francaise depuis l'Enfance) birth cohort (born in 2011) (ntotal = 5846) was used. Protein content of the infant formula received at 4 months was classified into five groups. Associations between protein content (or breastfed status) at 4 months and weight-, length- and BMI-for-age z-scores at 6, 12 and 18 months were analysed by multivariable linear regression. RESULTS: This analysis showed a positive association between protein content and weight-, length- and BMI-for-age z-scores at 6 months and only for weight-for-age at 12 months. At 6 months, as compared with the intermediate protein-content group (2.1-2.5 g/100 kcal), infants receiving very-high protein content (>2.8 g/100 kcal) had higher BMI-for-age z-score and those from the very-low protein-content group (<2.0 g/100 kcal) had lower BMI-for-age z-score. Exclusively breastfed infants had lower length and weight z-scores than formula-fed infants at any age. CONCLUSIONS: Our findings show a positive association, under real conditions of use, between protein contents in infant formula still on the market and weight-, length- and BMI-for-age z-scores from 6 to 18 months