Obesity alters the topographical distribution of ventilation and the regional response to bronchoconstriction.

Obesity is associated with reduced operating lung volumes that may contribute to increased airway closure during tidal breathing and abnormalities in ventilation distribution. We investigated the effect of obesity on the topographical distribution of ventilation before and after methacholine-induced bronchoconstriction using single-photon emission computed tomography (SPECT)-computed tomography (CT) in healthy subjects. Subjects with obesity (n = 9) and subjects without obesity (n = 10) underwent baseline and postbronchoprovocation SPECT-CT imaging, in which Technegas was inhaled upright and followed by supine scanning. Lung regions that were nonventilated (Ventnon), low ventilated (Ventlow), or well ventilated (Ventwell) were calculated using an adaptive threshold method and were expressed as a percentage of total lung volume. To determine regional ventilation, lungs were divided into upper, middle, and lower thirds of axial length, derived from CT. At baseline, Ventnon and Ventlow for the entire lung were similar in subjects with and without obesity. However, in the upper lung zone, Ventnon (17.5 ± 10.6% vs. 34.7 ± 7.8%, P < 0.001) and Ventlow (25.7 ± 6.3% vs. 33.6 ± 5.1%, P < 0.05) were decreased in subjects with obesity, with a consequent increase in Ventwell (56.8 ± 9.2% vs. 31.7 ± 10.1%, P < 0.001). The greater diversion of ventilation to the upper zone was correlated with body mass index (rs = 0.74, P < 0.001), respiratory system resistance (rs = 0.72, P < 0.001), and respiratory system reactance (rs = -0.64, P = 0.003) but not with lung volumes or basal airway closure. Following bronchoprovocation, overall Ventnon increased similarly in both groups; however, in subjects without obesity, Ventnon only increased in the lower zone, whereas in subjects with obesity, Ventnon increased more evenly across all lung zones. In conclusion, obesity is associated with altered ventilation distribution during baseline and following bronchoprovocation, independent of reduced lung volumes.NEW & NOTEWORTHY Using ventilation SPECT-computed tomography imaging in healthy subjects, we demonstrate that ventilation in obesity is diverted to the upper lung zone and that this is strongly correlated with body mass index but is independent of operating lung volumes and of airway closure. Furthermore, methacholine-induced bronchoconstriction only occurred in the lower lung zone in individuals who were not obese, whereas in subjects who were obese, it occurred more evenly across all lung zones. These findings show that obesity-associated factors alter the topographical distribution of ventilation.

Advancing performance evaluation standards for household water treatment technologies.

Diarrheal illnesses and fatalities continue to be major issues in many regions throughout the world. Household water treatment (HWT) technologies (including both point-of-use (POU) and point-of-entry (POE) treatment solutions) have been shown as able to deliver safe water in many low-income communities. However, as shown herein, there are important inconsistencies in protocols employed for validating performance of HWTs. The WHO does not stipulate influent concentration as a parameter that could influence removal efficacy, nor does it indicate an influent concentration range that should be used during technology evaluations. A correlation between influent concentration and removal is evidenced herein (R2 = 0.88) with higher influent concentrations resulting in higher log-removal values (LRVs). The absence of a recommended standard influent concentration of bacteria (as well as for viruses and protozoa) could have negative consequences in intervention efforts. Recommendations are provided that regulatory bodies should specify an influent concentration range for testing and verification of HWT technologies.

Investigating offering of vegetables by caregivers of preschool age children.

BACKGROUND: Research into the methods which caregivers use to encourage children to eat vegetables is limited, with minimal evidence about what the barriers are to offering these foods. Vegetable consumption in children is typically low, and so gaining information on these factors is vital in order to develop further caregiver-centred interventions to increase children's vegetable consumption. This study aimed to investigate the methods caregivers use to offer vegetables to preschool aged children, as well as the factors which influence whether and how caregivers present vegetables to their children. METHOD: Seventeen caregivers with a preschool aged child participated in focus groups to assess these questions. RESULTS: Thematic analysis indicated that caregivers use a range of methods to offer their children vegetables, with these methods falling into three broad categories: behavioural/active methods, passive methods and food manipulations. Influences on caregiver offering which emerged from the focus groups formed four categories: information, cost, parent factors and child factors. CONCLUSIONS: Together with large-scale quantitative data, this information can be used to shape future interventions aiming to increase children's vegetable intake as well as to tailor advice given to caregivers striving to achieve a healthful diet for their children.

Ab-initio reconstruction of complex Euclidean networks in two dimensions.

Reconstruction of complex structures is an inverse problem arising in virtually all areas of science and technology, from protein structure determination to bulk heterostructure solar cells and the structure of nanoparticles. We cast this problem as a complex network problem where the edges in a network have weights equal to the Euclidean distance between their endpoints. We present a method for reconstruction of the locations of the nodes of the network given only the edge weights of the Euclidean network. The theoretical foundations of the method are based on rigidity theory, which enables derivation of a polynomial bound on its efficiency. An efficient implementation of the method is discussed and timing results indicate that the run time of the algorithm is polynomial in the number of nodes in the network. We have reconstructed Euclidean networks of about 1000 nodes in approximately 24 h on a desktop computer using this implementation. We also reconstruct Euclidean networks corresponding to polymer chains in two dimensions and planar graphene nanoparticles. We have also modified our base algorithm so that it can successfully solve random point sets when the input data are less precise.

Meta-analysis of prospective trials determining the short- and mid-term effect of elective open and endovascular repair of abdominal aortic aneurysms on quality of life.

BACKGROUND: Repair of an abdominal aortic aneurysm (AAA) is undertaken to prevent rupture. Intervention is by either open repair (OR) or a more minimally invasive endovascular repair (EVAR). Quality-of-life (QoL) analysis is an important health outcome and a number of single studies have assessed QoL following OR and EVAR. This was a meta-analysis of published studies to assess the effect of an intervention on QoL in patients with an AAA. METHODS: A systematic literature search was undertaken for studies prospectively reporting QoL analysis in patients with an AAA undergoing elective intervention. A multivariable meta-analysis model was developed in which the outcomes were mean changes in QoL scores over time, both for all AAA repairs (OR and EVAR) and comparing OR with EVAR. RESULTS: Data were collated from 16 studies (14 OR, 12 EVAR). The results suggested that treating an AAA had an effect on patient-reported QoL, evident from the statistically significant changes predominantly in domains assessing physical ability and pain. QoL was affected most within the first 3 months after any form of intervention, and was more pronounced following OR. Furthermore, a deterioration in the Physical Component Summary score following an AAA repair (either OR or EVAR) was evident at 12 months after intervention. CONCLUSION: Treating an AAA deleteriously affects patient-reported QoL over the first year following intervention.

Stability and continuity of parentally reported child eating behaviours and feeding practices from 2 to 5 years of age.

Previous research suggests that many eating behaviours are stable in children but that obesigenic eating behaviours tend to increase with age. This research explores the stability (consistency in individual levels over time) and continuity (consistency in group levels over time) of child eating behaviours and parental feeding practices in children between 2 and 5 years of age. Thirty one participants completed measures of child eating behaviours, parental feeding practices and child weight at 2 and 5 years of age. Child eating behaviours and parental feeding practices remained stable between 2 and 5 years of age. There was also good continuity in measures of parental restriction and monitoring of food intake, as well as in mean levels of children's eating behaviours and BMI over time. Mean levels of maternal pressure to eat significantly increased, whilst mean levels of desire to drink significantly decreased, between 2 and 5 years of age. These findings suggest that children's eating behaviours are stable and continuous in the period prior to 5 years of age. Further research is necessary to replicate these findings and to explore why later developmental increases are seen in children's obesigenic eating behaviours.

Similarities between eating attitudes among friendship groups in childhood: the moderating role of child anxiety.

OBJECTIVE: This study explores the similarities between individual and group eating and weight concerns in 8-11-year-old children. It also evaluates whether child anxiety moderates the relationships between individual and group eating and weight concerns. METHODS: One hundred and fifty four children aged 8-11 completed questionnaires concerning their friendship groups, their eating and weight concerns, and their levels of anxiety. RESULTS: Children's own scores on dietary restraint, body dissatisfaction, and external eating were significantly correlated with their friendship groups' scores on dietary restraint. Child anxiety moderated the relationships between group dietary restraint and individual scores on external eating. Group levels of dietary restraint predicted higher levels of external eating in children with moderate or high anxiety. CONCLUSIONS: In pre-adolescent children, peer group levels of dietary restraint are related to individual eating and weight concerns. More anxious children may be more susceptible to peer influences on their eating behaviors.

Sibling eating behaviours and differential child feeding practices reported by parents.

The purpose of this study was to investigate the intra-familial relationships between parental reports of feeding practices used with siblings in the same family, and to evaluate whether differences in feeding practices are related to differences in siblings' eating behaviours. Eighty parents of two sibling children completed measures assessing their feeding practices and child eating behaviours. Parents reported using greater restrictive feeding practices with children who were fussier and desired to drink more than their sibling. Parents reported using more pressure to eat with siblings who were slower to eat, were fussier, emotionally under-ate, enjoyed food less, were less responsive to food, and were more responsive to internal satiety cues. Restriction and pressure to eat appear to be part of the non-shared environment which sibling children experience differently. These feeding practices may be used differently for children in the same family in response to child eating behaviours or other specific characteristics.

Predictors of maternal control of feeding at 1 and 2 years of age.

OBJECTIVE: To establish the best predictors of maternal use of controlling feeding practices at 1 and 2 years of age. DESIGN: A longitudinal study from birth to 2 years. PARTICIPANTS: Sixty-two mothers of 2-year-old children. MEASURES: Infant weight at birth, 6, 12 and 24 months, breastfeeding history, infant temperament and feeding difficulties at 6 and 12 months, maternal demographics at 12 and 24 months, maternal mental health at 6 and 12 months, maternal controlling feeding practices at 12 and 24 months. RESULTS: Controlling feeding practices at 1 year were predicted by perceptions of infant temperament at 6 months, birth weight, length of breastfeeding, mental health at 6 months, and mealtime negativity at 6 months. Parental control over feeding when their child reached 2 years was predicted by the mother's tendency to use that particular strategy at 1 year in combination with the perceptions of infant temperament and feeding problems at 1 year, weight at 1 year, length of breastfeeding in infancy, and/or maternal mental health at 1 year. CONCLUSIONS: Breastfeeding appears to promote subsequent monitoring, and is associated with reduced use of pressurising and restrictive feeding practices. Infant characteristics are important predictors of control at both 1 and 2 years of age. The use of controlling feeding practices is relatively stable from 1 to 2 years.

PDFfit2 and PDFgui: computer programs for studying nanostructure in crystals.

PDFfit2 is a program as well as a library for real-space refinement of crystal structures. It is capable of fitting a theoretical three-dimensional (3D) structure to atomic pair distribution function data and is ideal for nanoscale investigations. The fit system accounts for lattice constants, atomic positions and anisotropic atomic displacement parameters, correlated atomic motion, and experimental factors that may affect the data. The atomic positions and thermal coefficients can be constrained to follow the symmetry requirements of an arbitrary space group. The PDFfit2 engine is written in C++ and is accessible via Python, allowing it to inter-operate with other Python programs. PDFgui is a graphical interface built on the PDFfit2 engine. PDFgui organizes fits and simplifies many data analysis tasks, such as configuring and plotting multiple fits. PDFfit2 and PDFgui are freely available via the Internet.

The development of maternal self-esteem.

Although an important theoretical concept, little is known about the development of maternal self-esteem. This study explores the significance of maternal cognitions, psychopathological symptoms, and child temperament in the prediction of prenatal and postnatal maternal self-esteem. During pregnancy 162 women completed measures assessing their unhealthy core beliefs, psychopathological symptoms, and self-esteem. At 1 year postpartum 87 of these women completed measures assessing their self-esteem and their child's temperament. Overall maladaptive maternal core beliefs and psychopathological symptoms during pregnancy explained 19% of the variance in prenatal maternal self-esteem. Forty-two percent of the variance in maternal self-esteem at 1 year could be explained by a combination of prenatal maternal self-esteem, mental health symptoms, maternal core beliefs, and more unsociable infant temperament. Underlying maternal cognitive structures may be important in determining the development of maternal self-esteem.

A national survey of epidural use and management in elderly patients undergoing elective and emergency laparotomy.

A postal questionnaire was sent to anaesthetic clinical tutors in the United Kingdom describing two hypothetical 75-year-old patients requiring abdominal surgery. Patient 1 (ASA 2) required elective anterior resection and patient 2 (ASA 3-4) required emergency laparotomy. There was a 65% response rate. For patient 1, 98.5% of respondents would insert an epidural, 93% inserting this awake and 50% placing it in the high-mid thoracic region. All respondents would use local anaesthesia (concentration varied four-fold) and 62% would use opioids. All respondents would place the epidural pre-operatively; although 36% would administer the epidural block pre-operatively and 3% postoperatively. For patient 2, 70% of respondents would insert an epidural (p < 0.0001), drug administration would be more frequently delayed until postoperatively (13%); p = 0.0005) and epidural opioid use decreased (57%); p = n/s. Epidural insertion influenced the postoperative destination in 42% of departments. Use of a critical care facility was anticipated for more than half of these patients; 60% reported difficulty accessing critical care beds.

Breast-feeding, maternal feeding practices and mealtime negativity at one year.

This paper explores whether breast-feeding, mediated by lower maternal use of controlling strategies, predicts more positive mealtime interactions between mothers and their 1 year old infants. Eighty-seven women completed questionnaires regarding breast-feeding, assessing their control over child feeding and mealtime negativity at 1 year of infant age. Seventy-four of these women were also observed feeding their infants solid food at 1 year. Mediation analyses demonstrated that the experience of breast-feeding, mediated by lower reported maternal control over child feeding, predicted maternal reports of less negative mealtime interactions. The experience of breast-feeding also predicted observations of less conflict at mealtimes, mediated by observations of maternal sensitivity during feeding interactions. The implications of these findings are discussed.

Culling avalanches in bootstrap percolation.

We study the culling avalanches which occur after the "death" of a single randomly chosen site in a network where sites are unstable, and are culled, if they have coordination less than an integer parameter m. Avalanche distributions are presented for triangular and cubic lattices for values of m where the associated bootstrap transitions are either first or second order. In second order cases, the culling avalanche distribution is found to be exponential, while in first order cases it follows a power law. We present an exact relation between culling avalanches and conventional bootstrap percolation and show that a relation proposed by Manna [Physica A 261, 351 (1998)] can be a good approximation for strongly first order bootstrap transitions but not for continuous bootstrap transitions.