Assessing the contribution of vegetation to slope stability

Many embankments and cuttings associated with the transportation infrastructure in the UK are only marginally stable. Engineering techniques such as soil nailing, geosynthetic reinforcement, improved drainage and ground improvement by stabilisation are available to improve stability but the cost can be high. A lower cost solution may be to utilise vegetation, either self seeded or planted. The benefits and drawbacks associated with vegetation have been the subject of some debate. The problems caused by vegetation in relation to building foundations are well documented and confirm that vegetation can have very significant influences on geotechnical parameters. Appropriate properly maintained vegetation can have the same significant influence to help provide additional stability to soil slopes. This paper considers the potential engineering influences of vegetation and how it can be characterised on site within a geotechnical framework for stability assessments. The direct reinforcement available from the roots of trees and shrubs is identified as providing one of the most significant contributions to slope stability. Case studies in the UK, Greece and Italy demonstrate how results from in-situ root pull out tests may be used to estimate the potential reinforcement forces available from the roots. A scheme is presented to designate zones of influence within the soil according to the size and nature of the vegetation

The UK Women's Cohort Study: comparison of vegetarians, fish-eaters and meat-eaters

Background: This paper describes the development of the UK Women's Cohort Study and presents cohort baseline characteristics. Methods: In total, 35 372 women, aged 35–69 years at recruitment, were selected to ensure a wide range of dietary intakes. Diet was assessed by a 217-item food-frequency questionnaire (FFQ). Detailed lifestyle information was collected by postal questionnaire. Vegetarians, fish-eaters and meat-eaters were compared. Results: The cohort women are mainly white, well-educated, middle-class and married with children. They are health-conscious with only 11% current smokers and 58% taking dietary supplements. Twenty-eight per cent of subjects self-report as being vegetarian and 1% as vegan. However, only 18% are defined as 'vegetarian' from the FFQ. Fat provides 32% of energy; vitamin and mineral intakes are high, with a broad range of intakes. Meat-eaters are older, with a higher body mass index (BMI) and the lowest intakes of carbohydrate, fibre, vitamin C, folate, iron and calcium. Other fish-eaters are similar to vegetarians. Vegetarians have the lowest intakes of protein, fat and saturated fat. Oily fish-eaters have the lowest BMI; are the least likely to smoke or use full-fat milk; and are the most likely to use dietary supplements and consume the most fruit and vegetables. Oily fish-eaters have the highest total energy intake and vegetarians the lowest. Semi-skimmed milk, bread, potatoes, wine, bananas and muesli are important contributors to energy for all groups

Classical and Quantum Equations of Motion for a BTZ Black String in AdS Space

We investigate gravitational collapse of a $(3+1)$-dimensional BTZ black string in AdS space in the context of both classical and quantum mechanics. This is done by first deriving the conserved mass per unit length of the cylindrically symmetric domain wall, which is taken as the classical Hamiltonian of the black string. In the quantum mechanical context, we take primary interest in the behavior of the collapse near the horizon and near the origin (classical singularity) from the point of view of an infalling observer. In the absence of radiation, quantum effects near the horizon do not change the classical conclusions for an infalling observer, meaning that the horizon is not an obstacle for him/her. The most interesting quantum mechanical effect comes in when investigating near the origin. First, quantum effects are able to remove the classical singularity at the origin, since the wave function is non-singular at the origin. Second, the Schr\"odinger equation describing the behavior near the origin displays non-local effects, which depend on the energy density of the domain wall. This is manifest in that derivatives of the wavefunction at one point are related to the value of the wavefunction at some other distant point.Comment: 9 pages, 1 figure. Minor Clarification and corrections. Accepted for Publication in JHE

Infant arterial stiffness and maternal iron status in pregnancy: A UK birth cohort (Baby VIP study)

Background In animal studies, iron deficiency during pregnancy has been linked to increased offspring cardiovascular risk. No previous population studies have measured arterial stiffness early in life to examine its association with maternal iron status. Objective This study aimed to examine the association between maternal iron status in early pregnancy with infant brachio-femoral pulse wave velocity (PWV). Methods The Baby VIP (Baby’s Vascular health and Iron in Pregnancy) study is a UK-based birth cohort which recruited 362 women after delivery from the Leeds Teaching Hospitals postnatal wards. Ferritin and transferrin receptor levels were measured in maternal serum samples previously obtained in the first trimester. Infant brachio-femoral PWV was measured during a home visit at 2-6 weeks. Results Iron depletion (ferritin <15 ug/L) was detected in 79 (23%) women in early pregnancy. Infant PWV (m=6.7 m/s, sd=1.3, n=284) was not associated with maternal ferritin (adjusted change per 10 ug/L= 0.02, 95% CI -0.01, 0.1), nor with iron depletion (adjusted change = -0.2, 95% CI -0.6, 0.2). No evidence of association was observed between maternal serum transferrin receptor level or its ratio to ferritin with infant PWV. Maternal anaemia (<11 g/dL) at ≤20 weeks gestation was associated with a 1.0 m/s increase in infant PWV (adjusted 95% CI 0.1, 1.9). Conclusion This is the largest study to-date which assessed peripheral PWV as a measure of arterial stiffness in infants. There was no evidence of an association between markers of maternal iron status early in pregnancy and infant PWV

Caffeine intake during pregnancy and adverse birth outcomes: a systematic review and dose–response meta-analysis

Caffeine is commonly consumed during pregnancy, crosses the placenta, with fetal serum concentrations similar to the mother’s, but studies of birth outcome show conflicting findings. We systematically searched Medline and Embase for relevant publications. We conducted meta-analysis of dose–response curves for associations between caffeine intake and spontaneous abortion, stillbirth, preterm delivery, low birth weight and small for gestational age (SGA) infants. Meta-analyses included 60 unique publications from 53 cohort and case–control studies. An increment of 100 g caffeine was associated with a 14 % (95 % CI 10–19 %) increase in risk of spontaneous abortion, 19 % (5–35 %) stillbirth, 2 % (-2 to 6 %) preterm delivery, 7 % (1–12 %) low birth weight, and 10 % (95 % CI 6–14 %) SGA. There was substantial heterogeneity in all models, partly explained by adjustment for smoking and previous obstetric history, but not by prospective assessment of caffeine intake. There was evidence of small-study effects such as publication bias. Greater caffeine intake is associated with an increase in spontaneous abortion, stillbirth, low birth weight, and SGA, but not preterm delivery. There is no identifiable threshold below which the associations are not apparent, but the size of the associations are generally modest within the range of usual intake and are potentially explained by bias in study design or publication. There is therefore insufficient evidence to support further reductions in the maximum recommended intake of caffeine, but maintenance of current recommendations is a wise precaution

Risk of Hip Fracture in Meat Eaters, Pescatarians, and Vegetarians: A Prospective Cohort Study of 413,914 UK Biobank Participants

Background: Meat-free diets may be associated with a higher risk of hip fracture, but prospective evidence is limited. We aimed to investigate the risk of hip fracture in occasional meat-eaters, pescatarians, and vegetarians compared to regular meat-eaters in the UK Biobank, and to explore the role of potential mediators of any observed risk differences. Methods: Middle-aged UK adults were classified as regular meat-eaters (n=258,765), occasional meat-eaters (n=137,954), pescatarians (n=9557), or vegetarians (n=7638) based on dietary and lifestyle information at recruitment (2006-2010). Incident hip fractures were identified by record linkage to Hospital Episode Statistics up to September 2021. Multivariable Cox regression models were used to estimate associations between each diet group and hip fracture risk, with regular meat-eaters as the reference group, over a median follow-up time of 12.5 years. Findings: Among 413,914 women, 3503 hip fractures were observed. After adjustment for confounders, vegetarians (HR (95% CI): 1·50 (1·18, 1·91)) but not occasional meat-eaters (0·99 (0·93, 1·07)) or pescatarians (1·08 (0·86, 1·35)) had a greater risk of hip fracture than regular meat-eaters. This is equivalent to an adjusted absolute risk difference of 3·2 (1·2, 5·8) more hip fractures per 1000 people over 10 years in vegetarians. There was limited evidence of effect modification by BMI on hip fracture risk across diet groups (pinteraction = 0·08), and no clear evidence of effect modification by age or sex (pinteraction = 0·9 and 0·3, respectively). Mediation analyses suggest that BMI explained 28% of the observed risk difference between vegetarians and regular meat-eaters (95% CI: 1·1%, 69·8%). Interpretation: Vegetarian men and women had a higher risk of hip fracture than regular meat-eaters, and this was partly explained by their lower BMI. Ensuring adequate nutrient intakes and weight management are therefore particularly important in vegetarians in the context of hip fracture prevention

Associations of clothing size, adiposity and weight change with risk of postmenopausal breast cancer in the UK Women’s Cohort Study (UKWCS)

Objectives: Breast cancer is associated with overweight and obesity after menopause. However, clothing size as a proxy of adiposity in predicting postmenopausal breast cancer is not widely studied. We aimed to explore the relationships between postmenopausal breast cancer risk with adipose indicators (including clothing sizes) and weight change over adulthood. Design: Prospective cohort study. Setting: England, Wales and Scotland. Participants: 17 781 postmenopausal women from the UK Women’s Cohort Study. Primary: outcome measure Incident cases of malignant breast cancers (International Classification of Diseases (ICD) 9 code 174 and ICD 10 code C50). Results: From 282 277 person-years follow-up, there were 946 incident breast cancer cases with an incidence rate of 3.35 per 1000 women. Body mass index (HR: 1.04; 95% CI: 1.02 to 1.07), blouse size (HR: 1.10; 1.03 to 1.18), waist circumference (HR: 1.07; 1.01 to 1.14) and skirt size (HR: 1.14;1.06 to 1.22) had positive associations with postmenopausal breast cancer after adjustment for potential confounders. Increased weight over adulthood (HR: 1.02; 1.01 to 1.03) was also associated with increased risk for postmenopausal breast cancer. Conclusions: Blouse and skirt sizes can be used as adipose indicators in predicting postmenopausal breast cancer. Maintaining healthy body weight over adulthood is an effective measure in the prevention of postmenopausal breast cancer

Bitter taste sensitivity, food intake, and risk of malignant cancer in the UK Women’s Cohort Study

Purpose: There is variability in sensitivity to bitter tastes. Taste 2 Receptor (TAS2R)38 binds to bitter tastants including phenylthiocarbamide (PTC). Many foods with putative cancer preventive activity have bitter tastes. We examined the relationship between PTC sensitivity or TAS2R38 diplotype, food intake, and cancer risk in the UK Women’s Cohort Study. Methods: PTC taste phenotype (n = 5500) and TAS238 diplotype (n = 750) were determined in a subset of the cohort. Food intake was determined using a 217-item food-frequency questionnaire. Cancer incidence was obtained from the National Health Service Central Register. Hazard ratios (HR) were estimated using multivariable Cox proportional hazard models. Results: PTC tasters [HR 1.30, 95% confidence interval (CI) 1.04, 1.62], but not supertasters (HR 0.98, CI 0.76, 1.44), had increased cancer risk compared to nontasters. An interaction was found between phenotype and age for supertasters (p = 0.019) but not tasters (p = 0.54). Among women > 60 years, tasters (HR 1.40, CI 1.03, 1.90) and supertasters (HR 1.58, CI 1.06, 2.36) had increased cancer risk compared to nontasters, but no such association was observed among women ≤ 60 years (tasters HR 1.16, CI 0.84, 1.62; supertasters HR 0.54, CI 0.31, 0.94). We found no association between TAS2R38 diplotype and cancer risk. We observed no major differences in bitter fruit and vegetable intake. Conclusion: These results suggest that the relationship between PTC taster phenotype and cancer risk may be mediated by factors other than fruit and vegetable intake

Dietary fibre intake and risk of cardiovascular disease: systematic review and meta-analysis

To investigate dietary fibre intake and any potential dose-response association with coronary heart disease and cardiovascular disease