294 research outputs found
Community dynamics of Pleistocene coral reefs during alternative climatic regimes
Reef ecosystems built during successive periods of Pleistocene sea level rise have shown remarkable persistence in coral community structure, but little is known of the ecological characteristics of reef communities during periods of low sea stands or sea level falls. We sampled the relative species abundance of coral, benthic foraminifera, and calcareous red algae communities from eight submerged coral reefs in the Huon Gulf, Papua New Guinea, which formed during successive sea level fall and lowstand periods over the past 416 kyr. We found that dissimilarity in coral species composition increased significantly with increasing time between reef-building events. However, neither coral diversity nor the taxonomic composition of benthic foraminifera and calcareous red algae assemblages varied significantly over time. The taxonomic composition of coral communities from lowstand reefs was significantly different from that of highstand reefs previously reported from the nearby Huon Peninsula. We interpret the community composition and temporal dynamics of lowstand reefs as a result of shifting energy regimes in the Huon Gulf, and differences between low and highstand reefs as a result of differences in the interaction between biotic and environmental factors between the Huon Gulf and Huon Peninsula. Regardless of the exact processes driving these trends, our study represents the first glimpse into the ecological dynamics of coral reefs during low sea level stands when climatic conditions for reef growth were much different and less optimal than during previously studied highstand periods. Copyright ESA. All rights reserved
Vitamin B12, folate, and homocysteine in metabolic syndrome: a systematic review and meta-analysis
Background & aims: Metabolic syndrome (MetS) is associated with life-threatening conditions. Several studies have reported an association of vitamin B12, folic acid, or homocysteine (Hcy) levels with MetS. This systematic review and meta-analysis assessed the association of vitamin B12, folic acid, and Hcy levels with MetS. Methods: PubMed, Scopus, Embase, Ovid/Medline, and Web of Science were searched up to February 13, 2023. Cross-sectional, case-control, or cohort studies were included. A random-effects model was performed using the DerSimonian and Laird method to estimate the between-study variance. Effect measures were expressed as odds ratios (OR) with their corresponding 95% confidence intervals (95% CI). Between-study heterogeneity was evaluated using Cochran’s Q test and the I2 statistic. Results: Sixty-six articles (n = 87,988 patients) were included. Higher vitamin B12 levels were inversely associated with MetS (OR = 0.87; 95% CI: 0.81–0.93; p < 0.01; I2 = 90%). Higher Hcy levels were associated with MetS (OR = 1.19; 95% CI: 1.14–1.24; p < 0.01; I2 = 90%). Folate levels were not associated with MetS (OR = 0.83; 95% CI: 0.66–1.03; p = 0.09; I2 = 90%). Conclusion: Higher vitamin B12 levels were inversely associated with MetS, whereas higher Hcy levels were associated with MetS. Studies assessing the pathways underlying this association are requiredRevisión por pare
Middle Eocene Rhodoliths from Tropical and Mid-Latitude Regions
During the greenhouse conditions prevailing in the early–middle Eocene, larger benthic
foraminifers (LBF) spread out on carbonate platforms worldwide while rhodolith beds were scarcely
represented. This reduction in rhodolith beds coincided with a relative decrease in coralline algal
diversity and with a drastic decline of coral reef abundance. Middle Eocene rhodoliths from two
tropical (San Jacinto Fold Belt in northern Colombia and Bahoruco Peninsula in the Dominican
Republic) and two mid-latitude (Salinas Menores Ravine and Sierra del Zacatín in Southern Spain)
localities were studied. Rhodolith rudstones in the tropical areas accumulated on relatively deep
(several tens of meters) platform environments and were also redeposited in deeper settings downslope.
In Salinas Menores, rhodoliths are dispersed in planktic foraminifer-rich marls. Miliolids are common
in the infilling of constructional voids in these rhodoliths, indicating that they originally grew in
shallow-water inner-shelf settings and afterwards they were transported to deeper environments.
In Sierra del Zacatín, rhodoliths are scarce and coralline algae mainly occur as crusts attached to
and intergrowing with corals. Here, LBF dominated shallow-water carbonate platforms. In terms
of taxonomic composition, coralline algae of the order Hapalidiales are the most abundant in the
study areas, followed by Sporolithales. The order Corallinales is poorly represented except in Salinas
Menores, where it is relatively abundant and diverse. The impact of high temperatures due to high
levels of atmospheric CO2 during the Eocene and widespread oligotrophic conditions, which favored
formation of LBF-rich lithofacies, might account for the low abundance of rhodolith beds at mid and
high latitudes. In contrast, the more productive equatorial regions would have favored the formation
of rhodolith beds.This research was funded by Research Group RNM-190 of the Junta de Andalucía (JA and JCB),
MINECO/FEDER-UE project CGL2015-65404-R and by the Consolidated Research Group IT930-16 of the Basque
Government (VP and XOE)
An enigmatic kilometer-scale concentration of small mytilids (Late Miocene, Guadalquivir Basin, S Spain).
Upper Miocene heterozoan carbonates crop out extensively in a NE-SW-trending belt (42 km long and 1.5-8 km wide) along the so-called El Alcor topographic high, from Carmona to Dos Hermanas (Seville, S Spain). These carbonates formed at the southern active margin of the Guadalquivir Basin, the foreland basin of the Betic Cordillera. They change to marls basinward (NE) and to sands landward (SE and SW). Therefore, carbonate production was constrained to a limited area in an otherwise siliciclastic shelf. The carbonates (up to 40 m thick) overlie a gradually coarsening-upward succession of marls followed by silts and sandstones. The carbonate sequence can be divided into three subunits corresponding, frombottom to top, to lowstand, transgressive, and highstand system tract deposits. The lower subunit, exhibiting extensive trough cross-bedding, is interpreted as a shallow-water bar deposit. The intermediate subunit onlaps underlying sediments and was deposited in deeper, lowturbulence conditions. The upper subunit deposits accumulated in a well-oxygenated outer platform based on benthic foraminiferal assemblages. The presence of hummocky and swaley cross-stratification in these latter deposits suggests that theywere affected by storms. Pervasive fluid-escape structures are also observed throughout the carbonates. The three subunits consist of bioclastic packstones to rudstonesmade up of abundant fragments of smallmytilids. Isotopic data from serpulid polychaete Ditrupa tubes show 13C-depleted values (up to −16.1¿), whereas δ18O yields normal marine values. Additional isotopic data on shells of scallops, oysters, and small mussels, as well as bulk sediment, show diagenetic alterations. Based on actualistic examples of massive concentrations of mussels, the nearly monospecific composition of the El Alcor deposits, together with negative δ13C values of Ditrupa tubes, indicates that cold seeps presumably promoted carbonate formation. However, the absence of typical features of cold-seep deposits, such as authigenic carbonatesmediated by anaerobic bacterial activity and the typical chemosynthetic shelly organisms, makes the large carbonate body of El Alcor an unusual cold-seep deposit
Late glacial to deglacial variation of coralgal assemblages in the Great Barrier Reef, Australia
Integrated Ocean Drilling Program (IODP) Expedition 325 cored submerged reefs along the shelf edge of the Great Barrier Reef (GBR) to study sea-level and environmental changes and their impacts on reef communities and reef growth since the Last Glacial Maximum (LGM). Previous work defined five reef sequences (Reef 1–5) that span the last 30,000 years. Here we examined the variation in coralgal assemblages and their paleoenvironmental settings in late glacial to deglacial sequences from 23 holes cored seaward of the modern GBR in water depths from 46 to 131 m along four transects at three localities: Hydrographers Passage (HYD-01C and HYD-02A), Noggin Pass (NOG–01B), and Ribbon Reef (RIB-02A). We identified three coralline algal assemblages and eight coral assemblages indicating a broad range of reef settings from the shallow reef crest (0–5 m) to the deep forereef slope (>20 m). We document in detail for the first time the distribution and composition of reef communities that grew in the GBR during the LGM from 22,000–19,000 years ago. They included coral taxa that are major reef builders today: Isopora, Acropora gr. humilis, Dipsastraea gr. pallida, Porites, and Montipora. Prior to the fall in sea level to the maximum extent of the LGM, late glacial reef communities developed more proximally (landward) to the modern GBR along the shelf edge. Their distribution and composition reflect influences of the older Pleistocene basement depth and possible terrigenous sediment inputs. Post-LGM deglacial reef growth was vigorous in proximal sites and characterized by the accretion of a very shallow high-energy coralgal assemblage composed of medium to robustly branching Acropora, including A. gr. humilis, and thick algal crusts of Porolithon gr. onkodes associated with vermetid gastropods. More distally, reef growth was variably impacted by terrigenous input following deglacial reflooding of antecedent reef terraces. The coralgal succession and sedimentary facies in Noggin Pass indicate that an early drowning trend was linked to increased turbidity that was likely controlled by shelf morphology (narrow shelf, steep slope) and/or proximity to a paleo-river mouth. The deglacial succession in Ribbon Reef lacks typical shallow-water indicators, which may reflect influences of the particularly steep slope of the northern GBR shelf edge on reef zonation. A major sea-level jump at the onset of the Younger Dryas displaced reef habitats further upslope, forming a barrier reef system mainly composed of robustly branching acroporids distinct from the more distal sites. Our results highlight the importance of sedimentation and shelf morphology in addition to relative sea-level changes in controlling variations in reef community over centennial to millennial timescales. © 2019 Elsevier B.V.Australian Research Council-DP109400
Detecting Volunteer Cotton Plants in a Corn Field with Deep Learning on UAV Remote-Sensing Imagery
The cotton boll weevil, Anthonomus grandis Boheman is a serious pest to the
U.S. cotton industry that has cost more than 16 billion USD in damages since it
entered the United States from Mexico in the late 1800s. This pest has been
nearly eradicated; however, southern part of Texas still faces this issue and
is always prone to the pest reinfestation each year due to its sub-tropical
climate where cotton plants can grow year-round. Volunteer cotton (VC) plants
growing in the fields of inter-seasonal crops, like corn, can serve as hosts to
these pests once they reach pin-head square stage (5-6 leaf stage) and
therefore need to be detected, located, and destroyed or sprayed . In this
paper, we present a study to detect VC plants in a corn field using YOLOv3 on
three band aerial images collected by unmanned aircraft system (UAS). The
two-fold objectives of this paper were : (i) to determine whether YOLOv3 can be
used for VC detection in a corn field using RGB (red, green, and blue) aerial
images collected by UAS and (ii) to investigate the behavior of YOLOv3 on
images at three different scales (320 x 320, S1; 416 x 416, S2; and 512 x 512,
S3 pixels) based on average precision (AP), mean average precision (mAP) and
F1-score at 95% confidence level. No significant differences existed for mAP
among the three scales, while a significant difference was found for AP between
S1 and S3 (p = 0.04) and S2 and S3 (p = 0.02). A significant difference was
also found for F1-score between S2 and S3 (p = 0.02). The lack of significant
differences of mAP at all the three scales indicated that the trained YOLOv3
model can be used on a computer vision-based remotely piloted aerial
application system (RPAAS) for VC detection and spray application in near
real-time.Comment: 38 Page
Computer Vision for Volunteer Cotton Detection in a Corn Field with UAS Remote Sensing Imagery and Spot Spray Applications
To control boll weevil (Anthonomus grandis L.) pest re-infestation in cotton
fields, the current practices of volunteer cotton (VC) (Gossypium hirsutum L.)
plant detection in fields of rotation crops like corn (Zea mays L.) and sorghum
(Sorghum bicolor L.) involve manual field scouting at the edges of fields. This
leads to many VC plants growing in the middle of fields remain undetected that
continue to grow side by side along with corn and sorghum. When they reach
pinhead squaring stage (5-6 leaves), they can serve as hosts for the boll
weevil pests. Therefore, it is required to detect, locate and then precisely
spot-spray them with chemicals. In this paper, we present the application of
YOLOv5m on radiometrically and gamma-corrected low resolution (1.2 Megapixel)
multispectral imagery for detecting and locating VC plants growing in the
middle of tasseling (VT) growth stage of cornfield. Our results show that VC
plants can be detected with a mean average precision (mAP) of 79% and
classification accuracy of 78% on images of size 1207 x 923 pixels at an
average inference speed of nearly 47 frames per second (FPS) on NVIDIA Tesla
P100 GPU-16GB and 0.4 FPS on NVIDIA Jetson TX2 GPU. We also demonstrate the
application of a customized unmanned aircraft systems (UAS) for spot-spray
applications based on the developed computer vision (CV) algorithm and how it
can be used for near real-time detection and mitigation of VC plants growing in
corn fields for efficient management of the boll weevil pests.Comment: 39 page
Acceptance towards COVID-19 vaccination in Latin America and the Caribbean: A systematic review and meta-analysis
Introduction: Vaccination represents an important strategy to mitigate COVID-19 related morbidity and mortality by protecting against severe forms of the disease and reducing hospitalization and death rates. In this sense, the objective of this study is to estimate the prevalence of Vaccination Intention (VI) against COVID-19 in Latin America and Caribbean (LAC). Methods: We conducted a systematic review with a comprehensive search strategy for the following databases: PubMed, Scopus and Web of Science. A random-effect model meta-analysis was carried out using observational studies assessing the intention to vaccines against COVID-19 in LAC countries. The Clopper-Pearson method was used to estimate 95% Confidence Intervals. The quality assessment was developed using the Newcastle-Ottawa Scale adapted for cross-sectional studies. A subgroup analysis by study location and a sensitivity analysis were developed. Results: Nineteen cross-sectional studies were included. Five meta-analyzes were performed according to the target population of the included studies. The VI in the general population of LAC was 78.0% (95%CI: 74.0%–82.0%). The VI for non-pregnant women was 78.0% (95%CI: 58.0%–99.0%), for elderly population was 63.0% (95%CI: 59.0%–69.0%), for pregnant women was 69.0% (95%CI: 61.0%–76.0%) and for health-personnel was 83.0% (95% CI: 71.0%–96.0%). The sensitivity analysis for general population meta-analysis that included only low risk of bias studies showed a 77.0% VI (95%CI: 73.0%–82.0%) and for non-pregnant women, 85.0% VI (95%CI: 79.0%–90.0%). Conclusion: Despite the high prevalence of VI in general population found in our study, VI prevalence from elderly people and pregnant women are lower than other population groups and overall population.Revisión por pare
Response of the Great Barrier Reef to sea level and environmental changes over the past 30,000 years
Previous drilling through submerged fossil coral reefs has greatly improved our understanding of the general pattern of sea-level change since the Last Glacial Maximum, however, how reefs responded to these changes remains uncertain. Here we document the evolution of the Great Barrier Reef (GBR), the world\u27s largest reef system, to major, abrupt environmental changes over the past 30 thousand years based on comprehensive sedimentological, biological and geochronological records from fossil reef cores. We show that reefs migrated seaward as sea level fell to its lowest level during the most recent glaciation (~20.5-20.7 thousand years ago (ka)), then landward as the shelf flooded and ocean temperatures increased during the subsequent deglacial period (~20-10 ka). Growth was interrupted by five reef-death events caused by subaerial exposure or sea-level rise outpacing reef growth. Around 10 ka, the reef drowned as the sea level continued to rise, flooding more of the shelf and causing a higher sediment flux. The GBR\u27s capacity for rapid lateral migration at rates of 0.2-1.5 m yr−1 (and the ability to recruit locally) suggest that, as an ecosystem, the GBR has been more resilient to past sea-level and temperature fluctuations than previously thought, but it has been highly sensitive to increased sediment input over centennial-millennial timescales
A busca ativa de tuberculose pulmonar em Teresópolis, RJ, Brasil: a procura de sintomáticos respiratórios na emergência do Hospital das Clínicas de Teresópolis Costantino Ottaviano, Fundação Educacional Serra dos Órgãos
The aim of the present study was to investigate the detection percentage of tuberculosis among patients that are respiratory symptomatic (TB suspects). In this work, we present the preliminary results of research carried out at "Hospital das Clínicas de Teresópolis Costantino Ottaviano da Fundação Educacional Serra dos Órgãos (FESO)" from November 2003 to April 2004. Among the 40 respiratory symptomatic individuals identified and referred to the Tuberculosis Control Program in Teresópolis, two (5.0%) were characterized as smear-positive. These results confirm reports in the literature and underscore the need for and importance of this strategy.Investigar o percentual de detecção de tuberculose entre sintomáticos respiratórios é o objetivo do presente estudo. Nesta nota prévia, apresentam-se os resultados preliminares da pesquisa desenvolvida no Hospital das Clinicas de Teresópolis Costantino Ottaviano da Fundação Educacional Serra dos Órgãos (FESO), de novembro de 2003 a abril de 2004. Dos 40 sintomáticos respiratórios identificados e encaminhados ao Programa de Controle da Tuberculose do município de Teresópolis, dois (5.0%) foram caracterizados como bacilíferos. Esses resultados corroboram com os relatos da literatura e confirmam a necessidade e importância desta estratégia
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