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To assess iodine status and its effects on maternal thyroid function throughout pregnancy.
In the present prospective cohort study, three urinary samples were requested for urinary iodine concentration (UIC) determinations in both the first and third gestational trimesters. Serum thyrotropin (TSH) and free thyroxine (FT4) were analysed in both trimesters and thyroid antibodies were assessed once.
Rio de Janeiro, Brazil.
First-trimester pregnant women (n 243), of whom 100 were re-evaluated during the third trimester.
Iodine sufficiency was found in the studied population (median UIC=216·7 µg/l). The first- and third-trimester median UIC was 221·0 and 208·0 µg/l, respectively. TSH levels (mean (sd)) were higher in the third trimester (1·08 (0·67) v. 1·67 (0·86) mIU/l; P<0·001), while FT4 levels decreased significantly (1·18 (0·16) v. 0·88 (0·12) ng/dl; P<0·001), regardless the presence of iodine deficiency (UIC<150 µg/l) or circulating thyroid antibodies. UIC correlated (β; 95% CI) independently and negatively with age (–0·43; –0·71, –0·17) and positively with multiparity (0·15; 0·02, 0·28) and BMI (0·25; 0·00, 0·50). Furthermore, median UIC per pregnant woman tended to correlate positively with TSH (0·07; –0·01, 0·14). Women with median UIC≥250 µg/l and at least one sample ≥500 µg/l throughout pregnancy had a higher risk of subclinical hypothyroidism (OR=6·6; 95% CI 1·2, 37·4).
In this cohort with adequate iodine status during pregnancy, excessive UIC was associated with an increased risk of subclinical hypothyroidism.
There is an increasing consensus on the importance of understanding ecosystem service (ES) provision in order to facilitate decision making and the sustainable management of Neotropical dry forests (NTDFs), yet research on the ESs provided by NTDFs is limited. We identified the main existing gaps and trends in the quantification of provisioning, regulating and supporting ESs in NTDFs. Systematic web-based searches showed that research has been increasing in recent decades in NTDFs, supporting greater ES knowledge and assessment. Carbon storage and biodiversity are the main subjects under study, while ESs relating to water and soil lack investigation. The most common approaches for assessing ES were fauna and plant inventories, carbon dynamics and ecological processes.
With the combination of worldwide landscape changes and the uncertainty about the impact on species abundance and distribution, the value of spatio-temporal modelling tools is increasingly obvious. The Little Bustard Tetrax tetrax breeds on low-intensity arable cultivation and pastoral land and is currently threatened by diverse landscape modifications. The aim of this research was to predict Little Bustard population trends in the face of realistic scenarios of land use and infrastructure changes, applying a recently developed spatially explicit framework, based on the stochastic dynamic methodology (StDM). The application of this approach provided some basis to analyse the responses of breeding populations’ spatial distribution and abundance to the scenarios implemented. Since some of these scenarios represent local and/or regional risks to the viability of Little Bustard breeding populations, the results obtained demonstrate the potential of the proposed framework for landscape planning in the scope of the conservation of this threatened species. This approach also provides a promising baseline to support ecological risk assessments for other species, derived from ecological models with increased predictive power and intuitiveness to decision makers and environmental managers.
We report the occurrence of the sponge-dwelling snapping shrimp Synalpheus dardeaui (Decapoda: Alpheidae) for the first time from Porto Seguro (Bahia, Brazil) and record an additional sponge host for the species, Ircinia cf. strobilina. Synalpheus dardeaui was previously known from Florida and some localities in the Caribbean Sea. Therefore, the present finding represents the first record of the species in the south-western Atlantic, extending its southern distribution limit by a latitude of 28° from Curaçao (12°N) to Porto Seguro (16°S). Variations between the Brazilian and Florida–Caribbean materials are discussed and illustrated.
A new generation of radio telescopes with unprecedented capabilities for astronomy and fundamental physics will be in operation over the next few years. With high sensitivities and large fields of view, they are ideal for cosmological applications. We discuss their uses for cosmology focusing on the observational technique of HI intensity mapping, in particular at low redshifts (z < 4). This novel observational window promises to bring new insights for cosmology, in particular on ultra-large scales and at a redshift range that can go beyond the dark energy domination epoch. In terms of standard constraints on the dark energy equation of state, telescopes such as Phase I of the SKA should be able to obtain constrains about as well as a future galaxy redshift surveys. Statistical techniques to deal with foregrounds and calibration issues, as well as possible systematics are also discussed.
The aim of this study was to investigate the spatiotemporal variation in richness, abundance, structure and composition of phyllostomid bats over a successional gradient in a tropical dry forest in south-eastern Brazil. Four successional stages (pasture, early, intermediate and late) were sampled in the northern part of the state of Minas Gerais. Bats were sampled using mist nets at three sites for each of the four successional stages (12 sites in total) during eight periods between 2007 and 2009. A total of 537 individuals were captured (29 recaptured), distributed among four families and 22 species. Bat abundance and richness varied in space, being higher in the late-successional stage, and over time, being significantly lower during the dry season. When compared between guilds, only the abundance of omnivores varied significantly during the sampled months. Our results demonstrate that areas of late-successional stages showed higher bat richness and abundance in comparison with areas undergoing secondary succession. Our results also suggest the use of early-successional areas as flying routes by bats can lead to failure to detect differences in bat composition within successional gradients. We suggest future studies should assimilate landscape-level analyses into their studies to better evaluate the effects of successional gradients on bat assemblages.
Two distinct Pleistocene assemblages from SE Santiago Island are comparable to modern analogues elsewhere in the Cape Verde Islands. A low-diversity Siderastrea radians assemblage lived atop basalt knobs surrounded by sand on a slope below a cliff. A Millepora alcicornis–Megabalanus azoricus assemblage occupied the cliff. The latter was a typical rocky-shore assemblage from a high-energy setting below the tidal zone. Bioerosion structures in basalt produced by Circolites kotoncensis and Gastrochaenolites isp. also occur there. Despite extensive studies on local limestone deposits in 1832 and 1836, lack of exposure prevented Darwin from seeing these fossils.
The Pantanal is the world's largest tropical wetland and a biodiversity hotspot, yet its response to Quaternary environmental change is unclear. To address this problem, sediment cores from shallow lakes connected to the Upper Paraguay River (PR) were analyzed and radiocarbon dated to track changes in sedimentary environments. Stratal relations, detrital particle size, multiple biogeochemical indicators, and sponge spicules suggest fluctuating lake-level lowstand conditions between ~ 11,000 and 5300 cal yr BP, punctuated by sporadic and in some cases erosive flood flows. A hiatus has been recorded from ~ 5300 to 2600 cal yr BP, spurred by confinement of the PR within its channel during an episode of profound regional drought. Sustained PR flooding caused a transgression after ~ 2600 cal yr BP, with lake-level highstand conditions appearing during the Little Ice Age. Holocene PR flood pulse dynamics are best explained by variability in effective precipitation, likely driven by insolation and tropical sea-surface temperature gradients. Our results provide novel support for hypotheses on: (1) stratigraphic discontinuity of floodplain sedimentary archives; (2) late Holocene methane flux from Southern Hemisphere wetlands; and (3) pre-colonial indigenous ceramics traditions in western Brazil.
In twin pregnancy studies, molecular genetic techniques have rarely been used to determine zygosity, despite their known precision and accuracy. The present work aimed to assess the power of discrimination in zygosity assessment, using a set of microsatellite markers that were routinely used for aneuploidy screening by multiplex-PCR in a prenatal context. Rapid aneuploidy screening using a group of 20 microsatellite markers (STRs) located on chromosomes 13, 18, 21 and X has been performed in our lab for over 10 years, with a total of approximately 1,500 samples studied to date. A retrospective analysis of the 257 prenatal samples from multiple pregnancies was carried out. A subset of 14 cases presenting theoretical monozygosity were re-evaluated by the use of biostatistics tools accessed via the ZygProb website. Further monozygosity determination relative to dizygosity was calculated, given an estimated overall error value of 0.093%. The results show that monozygosity had been correctly determined in all our previously studied twins. This work demonstrates that accurate zygosity assessment can be achieved with the same STRs applied in aneuploidy screening with a high power of discrimination and a matching probability of over 99.999999%.
The effect of calcination temperature during the formation of the solid solution Sn0.9Ti0.1O2 doped with 1.00 mol % CoO and 0.05 mol % Nb2O5 is presented. The structural characteristics of this system were studied using X-ray diffraction, and the changes in phase formation were analyzed using the Rietveld method. With an increase in calcination temperature, there is increasing miscibility of Ti into the (Ti,Sn)O2 phase and near 1000 °C, and the remaining TiO2 (anatase) was transformed into the rutile phase. The sintering process, monitored using dilatometry, suggests two mass transport mechanisms, one activated close to 900 °C associated with the presence of TiO2 (anatase) and the second mechanism, occurring between 1200 and 1300 °C, is attributed to a faster grain boundary diffusion caused by oxygen vacancies.