Girl or boy? Prenatal lead, cadmium and mercury exposure and the secondary sex ratio in the ALSPAC study

AbstractThe aim of this study was to evaluate the effect of prenatal exposure to lead, cadmium and mercury levels on the secondary sex ratio. Whole blood samples were collected from pregnant women enrolled in the Avon Longitudinal Study of Parents and Children (ALSPAC) study at a median gestational age of 11 weeks and were analyzed for lead, cadmium and mercury. Regression analysis was used to identify associations between maternal lead, cadmium and mercury levels and the secondary sex ratio with adjustment for confounders. There was no evidence for associations between maternal lead, cadmium or mercury levels and the secondary sex ratio in this sample. It appears unlikely that alterations in the secondary sex ratio are influenced by exposure to heavy metals, but further work should be done in large cohorts in other countries to confirm these findings

Intake of game birds in the UK:assessment of the contribution to the dietary intake of lead by women of childbearing age and children

AbstractObjectiveConcern has recently been expressed about Pb levels in Pb-shot game meat. Our aim was to determine the consumption of game birds in a representative sample population in the UK, and in children and women of childbearing age in particular.DesignPopulation-based cross-sectional cohort study. Data from 4 d diet diaries from the UK National Diet and Nutrition Survey (NDNS; 2008–2010) were extracted to analyse data on game bird consumption in the sample population, in women of childbearing age (15–45 years old) and in children ≤6 years old.SettingHome-based study in representative areas of the UK.SubjectsParticipants in the NDNS (2008–2010; n 2126, age 1·5 to &gt;65 years).ResultsFifty-eight participants (2·7 %) reported eating game birds. The mean intake was 19·5 (sd 18·1) g/d (median 15·6, range 1·3–92·9 g/d). In women of childbearing age (15–45 years), 11/383 (2·9 %) reported eating game birds, with a mean intake of 22·4 (sd 25·8) g/d (median 15·6, range 2·0–92·9 g/d). In children aged ≤6 years old, 3/342 (0·9 %) were reported as eating game birds, with a mean intake of 6·8 (sd 9·7) g/d (median 2·4, range 1·3–23·2 g/d).ConclusionsThe prevalence of consumption of game birds by women of childbearing age and children ≤6 years old was relatively low and intakes were small. However, any exposure to Pb in these two groups is undesirable. As are uncertainties about the ability of the diet diary method to capture the consumption of food items that are infrequently consumed, alternative methods of capturing these data should be used in future studies.</jats:sec

Psychosocial and educational outcomes of weight faltering in infancy in ALSPAC

OBJECTIVES: To investigate whether infants with weight faltering have impaired psychosocial and educational outcomes in later childhood. DESIGN: Follow-up of infants with weight faltering in a large UK cohort study. SETTING: The Avon Longitudinal Study of Parents and Children (ALSPAC). PARTICIPANTS: 11 534 term infants from ALSPAC with complete weight records. Weight gain (conditional on initial weight) was calculated for three periods: from birth to 8 weeks, 8 weeks to 9 months, and birth to 9 months. Cases of weight faltering were defined as those infants with a conditional weight gain below the 5th centile, and these were compared with the rest of the cohort as the control group. OUTCOMES: Between 6 and 11 years, social, emotional and behavioural development was measured by direct assessment of the children and parental and teacher report. Educational outcomes included Standardised Assessment Test results at 7 and 11 years and Special Educational Needs status at age 11. RESULTS: Differences seen on univariate analysis in attention, non-verbal accuracy, educational attainment and special educational needs became non-significant after adjustment for confounding. Children with weight faltering in infancy did not differ from controls on any measures of self-esteem, peer relationships, experience of bullying, social cognition, antisocial activities, anxiety, depression or behavioural problems. CONCLUSIONS: Weight faltering in early infancy was associated with poorer educational outcomes in later childhood, but these associations were explained by confounding. The subsequent psychosocial development of infants with slow weight gain was not different from that of their peers

Alien Registration- Emond, Gabrielle M. (Lewiston, Androscoggin County)

https://digitalmaine.com/alien_docs/29366/thumbnail.jp

MS

thesisA new conductivity model, the Generalized Effective Medium Theory of Induced Polarization (GEMTIP) is tested with complex resistivity data and detailed mineralogy of porphyry system rock samples. The induced polarization (IP) effects are important phenomena for EM exploration. GEMTIP represents an expansion of the rock properties used for electromagnetic modeling of bulk apparent resistivity. The new model includes, mineral type, mineral size, mineral conductivity and other petrographic information. Rocks containing disseminated sulfides from porphyry systems are chosen as a good analog to the testing of the spherical grain analytic solution of GEMTIP. GEMTIP predicts the same trend in peak IP response as function of grain size for both chalcopyrite and pyrite containing synthetic rocks as a previous study, study. Inversion routines are developed and tested using synthetic data to recover the two empirical variables from recorded complex resistivity data. The two empirical variables are surface polarizability (a) and the decay coefficient (C). For three porphyry system rock samples, detailed geologic analysis using optical mineralogy, and X-ray tomography is conducted to determine GEMTIP model inputs. Sulfides in the rock samples exhibited a range of forms including near perfect cubes, stacked cubes, rounded, and complex amorphous forms. The sizes of sulfides varied from less than 0.01 mm to over 2 mm in radius. Measured surface area and surface area to volume ratios for each sample do not match the computed values assuming uniform spherical grains. Complex resistivity values are calculated from recorded EM data from 0.0156 Hz to 9216 Hz. Using the observed mineralogical data the GEMTIP model was able to fit the recorded complex resistivity data for the three samples with a the inclusion of an empirical factor to account for the difference in measured and computed spherical surface area reenforcing the role of surface area in the IP effect. Successful GEMTIP modeling of the rock samples provided insight into controlling factors of the IP effect. Forward geophysical modeling of copper porphyry systems is accomplished using geologic inputs from rock-scale to deposit-scale. For deposit scale modeling an Integral Equation method Electromagnetic forward modeling code IBCEM3DIP, developed by the Consortium for Electromagnetic Modeling and Inversion (CEMI) is used. A new interface to allow modeling of geometrically complex geologic systems was developed for the IBCEM3DIP code. The GEMTIP conductivity model was incorporated into IBCEM3DIP. Both the rock type and associated electric properties and mineralogical properties (approximate) are used for synthetic data creation. Using the new interface and developed Simplified Porphry Model as a template the effect of deposit-scale changes in sulfide distribution are tested on synthetic IP data. Although differences in the apparent resistivity data are subtle, changes in sulfide distribution strongly influence the apparent phase data. This highlights the importance of IP data and its use for mineral disrimination. With advances in the understanding of the IP effect through GEMTIP, forward modeling and inversion, detection and discrimination capability will improve for porphyry systems and other geologic targets, leading to greater efficiency in mineral exploration

Functional Trade-Offs in Promiscuous Enzymes Cannot Be Explained by Intrinsic Mutational Robustness of the Native Activity.

The extent to which an emerging new function trades off with the original function is a key characteristic of the dynamics of enzyme evolution. Various cases of laboratory evolution have unveiled a characteristic trend; a large increase in a new, promiscuous activity is often accompanied by only a mild reduction of the native, original activity. A model that associates weak trade-offs with "evolvability" was put forward, which proposed that enzymes possess mutational robustness in the native activity and plasticity in promiscuous activities. This would enable the acquisition of a new function without compromising the original one, reducing the benefit of early gene duplication and therefore the selection pressure thereon. Yet, to date, no experimental study has examined this hypothesis directly. Here, we investigate the causes of weak trade-offs by systematically characterizing adaptive mutations that occurred in two cases of evolutionary transitions in enzyme function: (1) from phosphotriesterase to arylesterase, and (2) from atrazine chlorohydrolase to melamine deaminase. Mutational analyses in various genetic backgrounds revealed that, in contrast to the prevailing model, the native activity is less robust to mutations than the promiscuous activity. For example, in phosphotriesterase, the deleterious effect of individual mutations on the native phosphotriesterase activity is much larger than their positive effect on the promiscuous arylesterase activity. Our observations suggest a revision of the established model: weak trade-offs are not caused by an intrinsic robustness of the native activity and plasticity of the promiscuous activity. We propose that upon strong adaptive pressure for the new activity without selection against the original one, selected mutations will lead to the largest possible increases in the new function, but whether and to what extent they decrease the old function is irrelevant, creating a bias towards initially weak trade-offs and the emergence of generalist enzymes.This work was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC, Discovery Grant RGPIN 418262- 12, http://www.nserc-crsng.gc.ca/), the Biotechnology and Biological Sciences Research Council (BBSRC, Grant BB/L002469/1, http://www. bbsrc.ac.uk/), the European Research Council (ERC, Advanced Investigator Grant 695669, https:// erc.europa.eu/), and the Human Frontiers Science Program (Grant RGP0006/2013, http://www.hfsp. org/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscrip

Low level lead exposure and pregnancy outcomes:dose–response relationships

BACKGROUND: National and international guidelines on safe levels for blood Pb in pregnancy focus on a threshold above which exposure is of concern. However, it has recently been suggested that the decrease in birth weight per unit increase in blood Pb is actually greater at lower than at higher concentrations of Pb without evidence of a lower threshold of effect. Our aim was to investigate whether there was evidence for a differential effect of maternal Pb levels on birth outcomes and/or a threshold value for effects. METHODS: Blood samples from pregnant women enrolled in the Avon Longitudinal Study of Parents and Children (ALSPAC) were analysed. Data collected on the infants included anthropometric variables. We fitted adjusted multivariable fractional polynomial models for birth outcomes. RESULTS: Adjusted models that assumed a linear relationship between untransformed blood Pb and the outcomes provided the best fit: an increase of 1 µg/dl was associated with changes in birth weight of −9.93 (95 % CI −20.27, 0.41) g, head circumference −0.03 (95 % CI −0.06, 0.00) cm and crown–heel length −0.05 (95 % CI −0.10, 0.00) cm. CONCLUSION: There was no evidence in this study to suggest a supralinear dose–response relationship or a lower threshold for the effect of maternal blood Pb on birth outcomes. This has implications for consideration of national and international guidelines on levels of concern in pregnancy. Exposure to Pb should be kept as low as possible during pregnancy to minimise adverse outcomes

Black holes in self-tuning cubic Horndeski cosmology

Observations of neutron star mergers in the late Universe have given significant restrictions to the class of viable scalar-tensor theories. In this paper we construct black holes within the “self-tuning” class of this restricted set, whereby the bare cosmological constant is absorbed by the dynamics of the scalar, giving a lower effective cosmological constant. We use analytic expansions at the singularity, black hole and cosmological horizon, and asymptotic region, coupled with numerical solutions, to find well-behaved black holes that asymptote to the self-tuned de Sitter geometry. The geometry differs from standard general relativity black holes near the horizon, and the scalar field velocity provides a hair for the black holes

Boltzmann equations for preheating

We derive quantum Boltzmann equations for preheating by means of the density matrix formalism, which account for both the non-adiabatic particle production and the leading collisional processes between the produced particles. In so doing, we illustrate the pivotal role played by pair correlations in mediating the particle production. In addition, by numerically solving the relevant system of Boltzmann equations, we demonstrate that collisional processes lead to a suppression of the growth of the number density even at the very early stages of preheating