22 research outputs found
Spatial and temporal patterns of Holocene precipitation change in the Iberian Peninsula
Precipitation is a key climate parameter of vegetation and ecosystems in the Iberian Peninsula. Here, we use a regional pollen-climate calibration model and fossil pollen data from eight sites from the Atlantic coast to southern Spain to provide quantitative reconstructions of annual precipitation trends and excursions and their regional patterns for the last 11 700 years. The Early Holocene (11 700 to 11 000 cal. a BP) was characterized by high precipitation values followed by a slowly declining trend until about 9000 cal. a BP in the south and about 8000 cal. a BP in the north. From 8000 to 6000 cal. a BP the reconstructed precipitation values are the highest in most records, especially in those located in the Mediterranean climatic region in the southern part of the peninsula, with maximum values nearly 100% higher than the modern reconstructed values. The results suggest a declining precipitation during the Late Holocene in the south, with a positive excursion at around 2500 cal. a BP, while in the north precipitation remained high until 500 cal. a BP. However, the Late Holocene climate reconstructions in the Iberian Peninsula are biased by intensifying human impact on vegetation. The statistical time series analyses using SiZer technique do not indicate any statistically significant high-frequency drought events in the region. In general, our results suggest regional differences in the precipitation patterns between the northern and southern parts of the peninsula, with a more distinct Middle Holocene period of high humidity in the south.Peer reviewe
Cervical pessary and cerclage placement for preterm birth prevention and cervicovaginal microbiome changes
Cervical length; Microbial diversity; PessaryLongitud cervical; Diversidad microbiana; PesarioLongitud cervical; Diversitat microbiana; PessariIntroduction
Our objective was to compare the vaginal microbiome in low-risk and high-risk pregnant women and to explore a potential association between vaginal microbiome and preterm birth.
Material and methods
A pilot, consecutive, longitudinal, multicenter study was conducted in pregnant women at 18–22 weeks of gestation. Participants were assigned to one of three groups: control (normal cervix), pessary (cervical length ≤25 mm) and cerclage (cervical length ≤25 mm or history of preterm birth). Analysis and comparison of vaginal microbiota as a primary outcome was performed at inclusion and at 30 weeks of gestation, along with a follow-up of pregnancy and perinatal outcomes. We assessed the vaginal microbiome of pregnant women presenting a short cervix with that of pregnant women having a normal cervix, and compared the vaginal microbiome of women with a short cervix before and after placement of a cervical pessary or a cervical cerclage.
Results
The microbiome of our control cohort was dominated by Lactobacillus crispatus and inners. Five community state types were identified and microbiome diversity did not change significantly over 10 weeks in controls. On the other hand, a short cervix was associated with a lower microbial load and higher microbial richness, and was not correlated with Lactobacillus relative abundance. After intervention, the cerclage group (n = 19) had a significant increase in microbial richness and a shift towards community state types driven by various bacterial species, including Lactobacillus mulieris, unidentified Bifidobacterium or Enterococcus. These changes were not significantly observed in the pessary (n = 26) and control (n = 35) groups. The cerclage group had more threatened preterm labor episodes and poorer outcomes than the control and pessary groups.
Conclusions
These findings indicate that a short cervix is associated with an altered vaginal microbiome community structure. The use of a cerclage for preterm birth prevention, as compared with a pessary, was associated with a microbial community harboring a relatively low abundance of Lactobacillus, with more threatened preterm labor episodes, and with poorer clinical outcomes.This study was supported by the Instituto de Salud Carlos III/FEDER FIS PI15/02043; Beca Dexeus Mujer 2015. Francisca Yáñez was supported by a grant from ANID, BECAS Chile, N° 72190278. Zixuan Xie received a fellowship from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie Action, Innovative Training Network: FunHoMic; grant number 812969
Spatial and temporal patterns of Holocene precipitation change in the Iberian Peninsula
Precipitation is a key climate parameter of vegetation and ecosystems in the Iberian Peninsula. Here, we use a regional pollen-climate calibration model and fossil pollen data from eight sites from the Atlantic coast to southern Spain to provide quantitative reconstructions of annual precipitation trends and excursions and their regional patterns for the last 11 700 years. The Early Holocene (11 700 to 11 000 cal. a BP) was characterized by high precipitation values followed by a slowly declining trend until about 9000 cal. a BP in the south and about 8000 cal. a BP in the north. From 8000 to 6000 cal. a BP the reconstructed precipitation values are the highest in most records, especially in those located in the Mediterranean climatic region in the southern part of the peninsula, with maximum values nearly 100% higher than the modern reconstructed values. The results suggest a declining precipitation during the Late Holocene in the south, with a positive excursion at around 2500 cal. a BP, while in the north precipitation remained high until 500 cal. a BP. However, the Late Holocene climate reconstructions in the Iberian Peninsula are biased by intensifying human impact on vegetation. The statistical time series analyses using SiZer technique do not indicate any statistically significant high-frequency drought events in the region. In general, our results suggest regional differences in the precipitation patterns between the northern and southern parts of the peninsula, with a more distinct Middle Holocene period of high humidity in the south.Peer reviewe
The Eurasian Modern Pollen Database (EMPD), version 2
The Eurasian (nee European) Modern Pollen Database (EMPD) was established in 2013 to provide a public database of high-quality modern pollen surface samples to help support studies of past climate, land cover, and land use using fossil pollen. The EMPD is part of, and complementary to, the European Pollen Database (EPD) which contains data on fossil pollen found in Late Quaternary sedimentary archives throughout the Eurasian region. The EPD is in turn part of the rapidly growing Neotoma database, which is now the primary home for global palaeoecological data. This paper describes version 2 of the EMPD in which the number of samples held in the database has been increased by 60% from 4826 to 8134. Much of the improvement in data coverage has come from northern Asia, and the database has consequently been renamed the Eurasian Modern Pollen Database to reflect this geographical enlargement. The EMPD can be viewed online using a dedicated map-based viewer at https://empd2.github.io and downloaded in a variety of file formats at https://doi.pangaea.de/10.1594/PANGAEA.909130 (Chevalier et al., 2019).Peer reviewe
69. Targuist mire (Central Rif, Morocco)
This work was supported by Consejería de Economía, Innovación, Ciencia y Empleo, Junta de Andalucía: [Grant Number A-RNM-688-UGR20]; Consejería de Transformación Económica, Industria, Conocimiento y Universidades: [Grant Number P18-RT-4963]; Ministerio de Ciencia e Innovación: [Grant Number RTI2018-101714-B-I00]Peer reviewe
A late antique vegetation history of the Western Mediterranean in context
International audienceFossil pollen records from 70 sites with reliable chronologies and high-resolution data in the western Mediterranean, were synthesised to document Late Holocene vegetation and climate change. The key elements of vegetation dynamics and landscape construction during Late Antiquity are clear in the light of the fossil pollen records. These are: fire events (natural or anthropogenically induced); grazing activities inhigh-mountain areas; agriculture; arboriculture; and human settlement in the lowlands. In terms of anthropogenic pressure, the differences recorded between highlands and lowlands suggest an imbalance in land use. Such practices were related to three main types of activities: wood exploitation and management, cultivation, and pastoralism. In lowland areas there seems to be some synchronism in vegetation dynamics during the late antique period, since most of the territories of the western Mediterranean had been deforested by the Early Roman period. However, in mountainous regions, pollen records document a clear asynchrony
A late antique vegetation history of the Western Mediterranean in context
International audienceFossil pollen records from 70 sites with reliable chronologies and high-resolution data in the western Mediterranean, were synthesised to document Late Holocene vegetation and climate change. The key elements of vegetation dynamics and landscape construction during Late Antiquity are clear in the light of the fossil pollen records. These are: fire events (natural or anthropogenically induced); grazing activities inhigh-mountain areas; agriculture; arboriculture; and human settlement in the lowlands. In terms of anthropogenic pressure, the differences recorded between highlands and lowlands suggest an imbalance in land use. Such practices were related to three main types of activities: wood exploitation and management, cultivation, and pastoralism. In lowland areas there seems to be some synchronism in vegetation dynamics during the late antique period, since most of the territories of the western Mediterranean had been deforested by the Early Roman period. However, in mountainous regions, pollen records document a clear asynchrony
Unraveling the naturalness of sweet chestnut forests (Castanea sativa Mill.) in central Spain
International audienc