Experiences of breastfeeding during COVID‐19: Lessons for future practical and emotional support

The COVID-19 pandemic and subsequent lockdown and social distancing led to changes to breastfeeding support available to women in the United Kingdom. Face-to-face professional support was reduced, and face-to-face peer support was cancelled. Anecdotal media accounts highlighted practices separating some mothers and babies in hospitals, alongside inaccurate stories of the safety of breastfeeding circulating. Meanwhile, new families were confined to their homes, separated from families and support networks. Given that we know breastfeeding is best supported by practices that keep mother and baby together, high-quality professional and peer-to-peer support, and positive maternal well-being, it is important to understand the impact of the pandemic upon the ability to breastfeed. To explore this, we conducted an online survey with 1219 breastfeeding mothers in the United Kingdom with a baby 0-12 months old to understand the impact of the pandemic upon breastfeeding duration, experiences and support. The results highlighted two very different experiences: 41.8% of mothers felt that breastfeeding was protected due to lockdown, but 27.0% of mothers struggled to get support and had numerous barriers stemming from lockdown with some stopped breastfeeding before they were ready. Mothers with a lower education, with more challenging living circumstances and from Black and minority ethnic backgrounds were more likely to find the impact of lockdown challenging and stop breastfeeding. The findings are vital in understanding how we now support those women who may be grieving their loss of breastfeeding and are affected by their negative experiences and how we can learn from those with a positive experience to make sure all breastfeeding women are better supported if similar future events arise

Proposal for a Simple Model of Dynamical SUSY Breaking

We discuss supersymmetric $SU(2)$ gauge theory with a single matter field in the $I=3/2$ representation. This theory has a moduli space of exactly degenerate vacua. Classically it is the complex plane with an orbifold singularity at the origin. There seem to be two possible candidates for the quantum theory at the origin. In both the global chiral symmetry is unbroken. The first is interacting quarks and gluons at a non-trivial infrared fixed point -- a non-Abelian Coulomb phase. The second, which we consider more likely, is a confining phase where the singularity is simply smoothed out. If this second, more likely, possibility is realized, supersymmetry will dynamically break when a tree level superpotential is added. This would be the simplest known gauge theory which dynamically breaks supersymmetry.Comment: 6 page

Immune Function Effects of Dental Amalgam in Children: A Randomized Clinical Trial

Background Dental amalgam is a widely used restorative material containing 50% elemental mercury that emits mercury vapor. No randomized clinical trials have determined whether there are adverse immunologic effects associated with this low-level mercury exposure in children. The objective of this study was to evaluate a sub-population of the New England Children’s Amalgam Trial (NECAT) for in vitro manifestations of immunotoxic effects of dental amalgam. Methods A randomized clinical trial in which children requiring dental restorative treatment were randomized to either amalgam for posterior restorations or resin composite. A total of 66 children, aged 6–10 years, were assessed for total white cell numbers, T-cell, B-cell, neutrophil and monocyte responsiveness over a five-year period. Owing to the small number of participants, the study is exploratory in nature with limited statistical power. Results The mean number of tooth surfaces restored during the five-year period was 7.8 for the amalgam group and 10.1 for composite group. In the amalgam group there was a slight, but not statistically significant, decline in responsiveness of T-cells and monocytes at 5–7 days post treatment; no differences were consistently observed at 6, 12 or 60 months. Conclusions This study confirms that treatment of children with dental amalgams leads to increased, albeit low level, exposure to mercury. In this exploratory analysis of immune function, amalgam exposure did not cause overt immune deficits, although small transient effects were observed 5–7 days post restoration. Clinical implications These findings suggest that immunotoxic effects of amalgam restorations in children need not be a concern when choosing this restorative dental material

Hypovitaminosis D among rheumatology outpatients in clinical practice.

OBJECTIVES: A role for vitamin D in the pathogenesis of autoimmune and inflammatory diseases is emerging. We undertook an audit of 25-hydroxyvitamin D (25OHD) investigation and treatment in rheumatology outpatients. METHODS: Serum 25OHD requests were matched to electronic medical records from rheumatology and metabolic bone clinics (April 2006-March 2007). Data were analysed separately for two groups, 'Documented osteoporosis/osteopaenia' (Group 1) and 'General rheumatology outpatients' (Group 2, sub-divided by diagnosis). Hypovitaminosis D was defined by 25OHD levels <50 nmol/l. Values were compared with healthy adults to calculate geometric z-scores. RESULTS: A total of 263 patients were included (Group 1, n = 122; Group 2, n = 141) with an overall median 25OHD of 44 nmol/l. The 25OHD level among general rheumatology patients (median 39 nmol/l, mean z score -1.2, was statistically significantly lower than among osteoporotic/osteopaenic patients (median 49 nmol/l, mean z score of -0.9, p < 0.05 for the difference). 25OHD was lower in inflammatory arthritis and chronic pain/fibromyalgia than in other groups. Prescribing was recorded in 100 in Group 1 (of whom 95% were prescribed calcium/800 IU cholecalciferol) and 83 in Group 2 (91% calcium/800 IU). Only 31% of the patients with 25OHD <50 nmol/l would have been identified using general guidelines for screening patients at 'high risk' of hypovitaminosis D. CONCLUSIONS: Improved guidelines for managing hypovitaminosis D in rheumatology patients are needed. We found a high prevalence of hypovitaminosis D among secondary care patients in rheumatology and widespread supplementation with 800 IU cholecalciferol. Substantially reduced levels of serum 25OHD were identified among patients with inflammatory arthritis and chronic pain

Universality of Nonperturbative Effects in c<1 Noncritical String Theory

Nonperturbative effects in c<1 noncritical string theory are studied using the two-matrix model. Such effects are known to have the form fixed by the string equations but the numerical coefficients have not been known so far. Using the method proposed recently, we show that it is possible to determine the coefficients for (p,q) string theory. We find that they are indeed finite in the double scaling limit and universal in the sense that they do not depend on the detailed structure of the potential of the two-matrix model.Comment: 17 page

Open Heterotic Strings

We classify potential cosmic strings according to the topological charge measurable outside the string core. We conjecture that in string theory it is this charge that governs the stability of long strings. This would imply that the SO(32) heterotic string can have endpoints, but not the E_8 x E_8 heterotic string. We give various arguments in support of this conclusion.Comment: 15 pages. v.2: typos, references correcte

ZZ brane amplitudes from matrix models

We study instanton contribution to the partition function of the one matrix model in the k-th multicritical region, which corresponds to the (2,2k-1) minimal model coupled to Liouville theory. The instantons in the one matrix model are given by local extrema of the effective potential for a matrix eigenvalue and identified with the ZZ branes in Liouville theory. We show that the 2-instanton contribution in the partition function is universal as well as the 1-instanton contribution and that the connected part of the 2-instanton contribution reproduces the annulus amplitudes between the ZZ branes in Liouville theory. Our result serves as another nontrivial check on the correspondence between the instantons in the one matrix model and the ZZ branes in Liouville theory, and also suggests that the expansion of the partition function in terms of the instanton numbers are universal and gives systematically ZZ brane amplitudes in Liouville theory.Comment: 29 pages, 4 figures; v2:how to scale x is generalized; v3:introduction and the last section are revised, typos correcte