Combinatorial models of rigidity and renormalization

We first introduce the percolation problems associated with the graph theoretical concepts of $(k,l)$-sparsity, and make contact with the physical concepts of ordinary and rigidity percolation. We then devise a renormalization transformation for $(k,l)$-percolation problems, and investigate its domain of validity. In particular, we show that it allows an exact solution of $(k,l)$-percolation problems on hierarchical graphs, for $k\leq l<2k$. We introduce and solve by renormalization such a model, which has the interesting feature of showing both ordinary percolation and rigidity percolation phase transitions, depending on the values of the parameters.Comment: 22 pages, 6 figure

Systematic review of outcomes and complications in nonimplant-based mastopexy surgery.

Mastopexy is one of the most performed cosmetic surgery procedures in the U.S. Numerous studies on mastopexy techniques have been published in the past decades, including case reports, retrospective reviews, and prospective studies. However, to date, no study has investigated the overall complications or satisfaction rates associated with the wide spectrum of techniques. This review aims to assess the outcomes of the various mastopexy techniques, without the use of implants, thus focusing on associated complications, and to provide a simplified classification system. This systematic review was performed in accordance with the PRISMA guidelines. PubMed database was queried in search of clinical studies describing nonprosthetic mastopexy techniques, which reported the technique, indication, and outcomes. Thirty-four studies, published from 1980 through 2016, were included and represented 1888 treated patients. Four main surgical technique categories were identified: dermal reshape, glandular reshape, glandular reshape associated with perforator flaps, and glandular reshape with mesh support. Despite varying techniques, mastopexy was generally found to be a reliable esthetic procedure with unsatisfactory breast shape, thus accounting for only 1.3% of the patients. The overall complication rate was 10.4%. The most represented complications were scar-related (3%, including hypertrophic or unesthetic appearance) and nipple-areola-related problems (2.9%; including distortion, asymmetry, and reduction in sensation). Mastopexy techniques achieve high patient satisfaction and can be tailored according to patient needs and clinical presentation. Complication rates and morbidity are relatively low. However, a significant number of issues related to scars, asymmetry, and potential ptosis recurrence should be highlighted in the information provided to patients

Assessing the influence of preconception diet on male fertility: a systematic scoping review

Advance Access Publication Date: January 17, 2024BACKGROUND: The last decade has seen increased research on the relationship between diet and male fertility, but there are no clearly defined nutritional recommendations for men in the preconception period to support clinical fertility outcomes. OBJECTIVE AND RATIONALE: The purpose of this scoping review is to examine the extent and range of research undertaken to evaluate the effect(s) of diet in the preconception period on male clinical fertility and reproductive outcomes. SEARCH METHODS: Four electronic databases (MEDLINE and EMBASE via Ovid, CAB Direct, and CINAHL via EBSCO) were searched from inception to July 2023 for randomized controlled trials (RCTs) and observational studies (prospective/retrospective, case–control, and cross-sectional). Intervention studies in male participants or couples aiming to achieve dietary or nutritional change, or non-intervention studies examining dietary or nutritional components (whole diets, dietary patterns, food groups or individual foods) in the preconception period were included. Controls were defined as any comparison group for RCTs, and any/no comparison for observational studies. Primary outcomes of interest included the effect(s) of male preconception diet on clinical outcomes such as conception (natural or via ART), pregnancy rates and live birth rates. Secondary outcomes included time to conception and sperm parameters. OUTCOMES: A total of 37 studies were eligible, including one RCT and 36 observational studies (prospective, cross-sectional, and case–control studies; four studies in non-ART populations) published between 2008 and 2023. Eight reported clinical outcomes, 26 reported on secondary outcomes, and three reported on both. The RCT did not assess clinical outcomes but found that tomato juice may benefit sperm motility. In observational studies, some evidence suggested that increasing fish or reducing sugar-sweetened beverages, processed meat or total fat may improve fecundability. Evidence for other clinical outcomes, such as pregnancy rates or live birth rates, showed no relationship with cereals, soy and dairy, and inconsistent relationships with consuming red meat or a ‘healthy diet’ pattern. For improved sperm parameters, limited evidence supported increasing fish, fats/fatty acids, carbohydrates and dairy, and reducing processed meat, while the evidence for fruits, vegetables, cereals, legumes, eggs, red meat and protein was inconsistent. Healthy diet patterns in general were shown to improve sperm health. WIDER IMPLICATIONS: Specific dietary recommendations for improving male fertility are precluded by the lack of reporting on clinical pregnancy outcomes, heterogeneity of the available literature and the paucity of RCTs to determine causation or to rule out reverse causation. There may be some benefit from increasing fish, adopting a healthy dietary pattern, and reducing consumption of sugar-sweetened beverages and processed meat, but it is unclear whether these benefits extend beyond sperm parameters to improve clinical fertility. More studies exploring whole diets rather than singular foods or nutritional components in the context of male fertility are encouraged, particularly by means of RCTs where feasible. Further assessment of core fertility outcomes is warranted and requires careful planning in high-quality prospective studies and RCTs. These studies can lay the groundwork for targeted dietary guidelines and enhance the prospects of successful fertility outcomes for men in the preconception period. Systematic search of preconception diet suggests that increasing fish and reducing sugary drinks, processed meats and total fat may improve male fertility, while consuming healthy diets, fish, fats/fatty acids, carbohydrates and dairy and reducing processed meat can improve sperm health.Cathryn A. Tully, Simon Alesi, Nicole O. McPherson, David J. Sharkey, Xiao Tong Teong, Chau Thien Tay, Thais Rasia Silva, Carolyn Puglisi, Jacqueline P. Barsby, Lisa J. Moran, Jessica A. Grieger, and Aya Mous

Spin waves in nickel nanorings of large aspect ratio

10.1103/PhysRevLett.94.137208Physical Review Letters9413-PRLT