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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
Classical nonlinear models to describe the growth curve for Murrah buffalo breed
With the objective of to adjust nonlinear models for the growth curves for a buffaloes herd raised in floodable lands in Rio Grande do Sul state, monthly records measured from birth to two years-old of 64 males and 63 females born between 1982 and 1989 were used. The models used were: Von Bertalanffy, Brody, Gompertz and Logistic. The parameters were estimated by NLIN procedure and the criteria used to evaluate the adjustment given by the models were: asymptotic standard deviation; coefficient of determination; average absolute deviation of residues and asymptotic index. Von Bertalanffy and Brody models overestimated the male asymptotic weight (A) in 15.9 and 171.3kg, respectively, and the Gompertz and Logistic models underestimated it in 4.5 and 13.4kg, respectively. For females, the Logistic model underestimated the asymptotic weight (-2.09kg), and Gompertz, Von Bertalanffy and Brody overestimated this parameter in 8.04, 17.7, and 280.33kg, respectively. The biggest average deviation was estimated by Brody model for both sexes, characterizing the biggest index. Considering the criteria, it is recommended the Gompertz and Logistic models for adjust females and males Murrah buffaloes breed growth curves.Com o objetivo de ajustar modelos não-lineares ao crescimento ponderal para búfalos criados em terras baixas no Estado do Rio Grande do Sul, foram utilizados registros mensais mensurados do nascimento aos dois anos de idade de 64 machos e 63 fêmeas, nascidos no período de 1982 a 1989. Utilizaram-se os modelos: Von Bertalanffy, Brody, Gompertz e Logístico. Os parâmetros foram estimados usando o procedimento NLIN e os critérios utilizados para verificar o ajuste dos modelos foram: desvio padrão assintótico; coeficiente de determinação; desvio médio absoluto dos resíduos e o índice assintótico. Os modelos Von Bertalanffy e Brody superestimaram o peso assintótico (A) para os machos em 15,9 e 171,3kg, respectivamente, e os modelos Gompertz e Logístico, subestimaram em 4,5 e 13,4kg, respectivamente. Para as fêmeas, o modelo Logístico subestimou o peso assintótico (-2,09kg) e os modelos Gompertz, Von Bertalanffy e Brody superestimaram esse parâmetro em: 8,04; 17,7 e 280,33kg, respectivamente. O maior desvio médio absoluto foi estimado pelo modelo Brody para ambos os sexos, caracterizando o melhor índice. Considerando os critérios, recomenda-se o modelo Gompertz e o modelo Logístico para ajustar a curva de crescimento de fêmeas e machos da raça Murrah
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
Stomatal behavior and components of the antioxidative system in coffee plants under water stress
Coffee (Coffea arabica) plants show a positive relationship between stomatal closure and formation and accumulation of H2O2. However, for coffee plants under water restriction such relationship has never been studied. The objective of the present study was evaluate the stomatal movement and the antioxidant capacity of coffee seedlings under different water regimes. Eight months old coffee seedlings of cv. Catuaí IAC 99 were submitted to field capacity, gradual and total suspension of irrigation during a period of 21 days. Evaluations of leaf water potential (Ψw) were performed in the beginning of the morning, and stomatal resistance, transpiration rate and vapor pressure deficit were determined at 10 am and 5 pm. All biochemical and enzymatic determinations were performed in leaves collected at 5 pm. Evaluations and samplings were performed at three days intervals. There was no variation in Ψw during the evaluated period for plants in field capacity. However, an expressive decrease of Ψw following day 12, reaching values near -2.5 MPa at the end of the experiment was observed for plants submitted to gradual suspension of irrigation. For plants submitted to total suspension of irrigation, Ψw decreases after the sixth day, reaching -2.5 MPa at day 15. The decay of Ψw in plants submitted to gradual and total suspension of irrigation reflected in increased stomatal resistance and in a decreased transpiration rate leading to an increase in hydrogen peroxide formation and, on final stages, increase in lipid peroxidation. As a conclusion, an increase in the activity of antioxidant enzymes as well as in the levels of ascorbate and dehydroascorbate was observed, which act in the detoxification of free radicals formed as result of the water stress.Para o cafeeiro (Coffea arabica) existe uma comprovada relação positiva entre fechamento estomático e formação e acúmulo de H2O2. Entretanto, tal relação para a cultura sob restrição hídrica ainda não foi estudada. Avaliou-se o movimento estomático e a capacidade antioxidante em mudas de cafeeiro sob diferentes regimes hídricos. Mudas de cafeeiro cv. Catuaí IAC 99, com oito meses de idade, foram submetidas à capacidade de campo, suspensão gradativa e suspensão total da irrigação por um período de 21 dias. Foram realizadas avaliações do potencial hídrico (Ψw) foliar na antemanhã e resistência estomática, taxa transpiratória e déficit de pressão de vapor foram avaliados as 10h00 e 17h00. As determinações bioquímicas e enzimáticas foram realizadas em folhas coletadas às 17h00. Todas as avaliações e coletas foram realizadas em intervalos de três dias. Nas plantas em capacidade de campo não houve variação no Ψw durante o período de avaliação. Para a suspensão gradativa da irrigação, houve queda expressiva a partir dos 12 dias, chegando próximo a -2,5 Mpa, ao final do experimento. Já nas plantas em suspensão total da irrigação observou-se queda no Ψw a partir do sexto dia, chegando a -2,5 MPa aos 15 dias. A queda no Ψw para as plantas em suspensão gradual e total da irrigação refletiu em aumentos na resistência estomática e diminuição da taxa transpiratória, ocasionando aumento na formação de peróxido de hidrogênio e nos períodos finais, aumentos na peroxidação de lipídios. Em conseqüência obervaram-se aumentos na atividade das enzimas antioxidantes, bem como nos teores de ascorbato e dehidroascorbato, atuando na detoxificação dos radicais livres formados em função do estresse
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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