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Inter- and intra-specimen variability masks reliable temperature control on shell Mg/Ca ratios in laboratory and field cultured Mytilus edulis and Pecten maximus (bivalvia).
yesThe Mg/Ca ratios of biogenic calcite is commonly
seen as a valuable palaeo-proxy for reconstructing
past ocean temperatures. The temperature dependence of
Mg/Ca ratios in bivalve calcite has been the subject of contradictory
observations. The palaeoceanographic use of a
geochemical proxy is dependent on initial, rigorous calibration
and validation of relationships between the proxy
and the ambient environmental variable to be reconstructed.
Shell Mg/Ca ratio data are reported for the calcite of two bivalve
species, Mytilus edulis (common mussel) and Pecten
maximus (king scallop), which were grown in laboratory
culturing experiments at controlled and constant aquarium
seawater temperatures over a range from 10 to 20 C.
Furthermore, Mg/Ca ratio data of laboratory- and fieldgrown
M. edulis specimens were compared. Only a weak,
albeit significant, shell Mg/Ca ratio¿temperature relationship
was observed in the two bivalve species: M. edulis
(r2=0.37, p<0.001 for laboratory-cultured specimens and
r2=0.50, p<0.001 for field-cultured specimens) and P. maximus
(r2=0.21, p<0.001 for laboratory-cultured specimens
only). In the two species, shell Mg/Ca ratios were not found
to be controlled by shell growth rate or salinity. The Mg/Ca
ratios in the shells exhibited a large degree of variability
among and within species and individuals. The results suggest
that the use of bivalve calcite Mg/Ca ratios as a temperature
proxy is limited, at least in the species studied to
date. Such limitations are most likely due to the presence
of physiological effects on Mg incorporation in bivalve calcite.
The utilization is further limited by the great variability
both within and among shells of the same species that were
precipitated under the same ambient condition
Historical separation and present-day structure of common dolphinfish (Coryphaena hippurus) populations in the Atlantic Ocean and Mediterranean Sea
The common dolphinfish (Coryphaena hippurus) is an epipelagic, mid-trophic level, highly migratory species distributed throughout the
world’s tropical and subtropical oceans in waters greater than 20C. Life-history variables, migratory behaviour, and genetic markers have
been used to define major stocks in the central Atlantic Ocean and Mediterranean Sea. Here, we used the mitochondrial DNA gene NADH
subunit 1 (688 bp) to test for differences between population groups. A total of 103 haplotypes were detected among 203 fish. Gene diversities in samples were large and similar among populations (mean h ¼ 0.932; range 0.894–0.987), but nucleotide diversities varied widely among
samples (range p ¼ 0.004–0.034) and appear to reflect population histories. Principal component analysis revealed two large populations
groups, and the analysis of molecular variation and pairwise values of UST resolved population structure within these groups. Populations in
the eastern Atlantic and Mediterranean showed the largest amounts of divergence from one another (UCT ¼ 0.331). Adult movement and
biophysical barriers to larval dispersal may explain contemporary differences between stocks, but the divergent populations in the Mediterranean Sea are likely due to isolations by cold temperature barriers during Pleistocene glaciations. The geographically large stock
groupings require international cooperation in the harvest management and conservation of local dolphinfish populations
Management of children visiting the emergency department during out-of-office hours: An observational study
Background The aim was to study the characteristics
and management of children visiting the emergency
department (ED) during out-of-office hours.
Methods We analysed electronic health record data from
119 204 children visiting one of five EDs in four European
countries. Patient characteristics and management
(diagnostic tests, treatment, hospital admission and
paediatric intensive care unit admission) were compared
between children visiting during office hours and evening
shifts, night shifts and weekend day shifts. Analyses were
corrected for age, gender, Manchester Triage System
urgency, abnormal vital signs, presenting problems and
hospital.
Results Patients presenting at night were younger
(median (IQR) age: 3.7 (1.4–8.2) years vs 4.8 (1.8–9.9)),
more often classified as high urgent (16.3% vs 9.9%) and
more often had ≥2 abnormal vital signs (22.8% vs 18.1%)
compared with office hours. After correcting for disease
severity, laboratory and radiological tests were less likely
to be requested (adjusted OR (aOR): 0.82, 95% CI 0.78–
0.86 and aOR: 0.64, 95% CI 0.60–0.67, respectively);
treatment
Extratos etanólicos de manga como antioxidantes na alimentação de poedeiras
O objetivo deste trabalho foi avaliar o efeito de extratos etanólicos do caroço e da casca de manga, sobre o desempenho de poedeiras e sobre a qualidade e estabilidade lipídica dos ovos. Um total de 180 poedeiras comerciais Hisex White foi distribuído ao acaso em seis tratamentos, com cinco repetições de seis aves. Os tratamentos consistiram de: ração sem adição de antioxidante; ração com 200 ppm do antioxidante butilato de hidroxitolueno (BHT); ração com 200 ou 400 ppm de extrato da casca de manga (Ecas); ração com 200 ou 400 ppm de extrato de caroço de manga (Ecar). Foram avaliados: o consumo de ração, a produção de ovos, o peso do ovo, a massa de ovo produzida (grama por ave por dia), a conversão alimentar e características de qualidade dos ovos. A oxidação lipídica da gema durante o armazenamento foi determinada pela quantificação das substâncias reativas ao ácido tiobarbitúrico. As aves alimentadas com a ração sem adição de antioxidantes produziram ovos com os piores valores de unidade Haugh e maior oxidação lipídica da gema. Os teores de 400 ppm de Ecas e 200 ou 400 ppm de Ecar foram efetivos na prevenção de danos oxidativos aos ovos durante o armazenamento e podem ser utilizados na alimentação das poedeiras como substituto ao antioxidante sintético
Polarimetric SAR Image Segmentation with B-Splines and a New Statistical Model
We present an approach for polarimetric Synthetic Aperture Radar (SAR) image
region boundary detection based on the use of B-Spline active contours and a
new model for polarimetric SAR data: the GHP distribution. In order to detect
the boundary of a region, initial B-Spline curves are specified, either
automatically or manually, and the proposed algorithm uses a deformable
contours technique to find the boundary. In doing this, the parameters of the
polarimetric GHP model for the data are estimated, in order to find the
transition points between the region being segmented and the surrounding area.
This is a local algorithm since it works only on the region to be segmented.
Results of its performance are presented
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