349 research outputs found
Attack intensity of Corythucha ciliata (Hemiptera, Tingidae) on Platanus spp. in an urban area in Portugal: a comparison between pruned and unpruned trees.
Corythucha ciliata (Say, 1832), commonly known as sycamore lace bug (SLB), is an insect species native to North America. Since its accidental introduction in Europe (through Italy) in 1964, it has expanded across most European countries. The arrival of SLB in Portugal is uncertain but its distribution is wide. Sycamore (Platanus spp.), the only host of SLB, is one of the most widespread and important urban tree species in Portugal. It provides a wide range of environmental, social and economical benefits, which have been threatened by the invasion of this pest. SLB damages trees by feeding on the underside of the leaves causing discoloration and eventually premature senescence. While the long-term effect of SLB on the health of urban trees is yet to be fully assessed, there is compelling evidence that pruning further increases SLB damage. In this study we assessed the impact of pruning on the attack intensity of SLB. To test the hypothesis that pruning promotes the invasion of SLB, we compared the intensity of attack of pruned trees with unpruned trees. We collected sycamore leaves from pruned and unpruned trees and then assessed the intensity of attack by scaling damage by visual rating. Our findings show that pruned trees exhibit significantly higher attack intensities than unpruned trees (p < 0,001, χ2 goodness of fit). Based on these findings we recommend that sycamore pruning should be performed with caution (or even ceased), especially in urban areas where SLB is present
Coccinelídeos associados ao olival português e sua importância na protecção contra a cochonilha-negra, Saissetia oleae (Olivier)
Os coccinelídeos são um dos grupos de insectos predadores mais importantes nos ecossistemas
agrícolas e, no olival são dos principais inimigos da cochonilha-negra, Saissetia oleae. Neste trabalho
indicam-se as espécies de coccinelídeos identificadas em olivais localizados nas principais regiões
olivícolas portuguesas (Alto Alentejo. Trás-os-Montes e Beira interior Norte) e analisa-se o papel
das espécies consideradas de maior importância na limitação natural da cochonilha-negra. Os dados
apresentados obtiveram-se em 1999 e 2000 e entre 2002 e 2004. por amostragem, através da
técnica das pancadas, realizada semanal ou quinzenalmente. As populações de cochonilha-negra
amostraram-se quinzenalmente, em 2002 e 2003, através da observação de cinco amostras de 160
folhas provenientes de dez árvores, em dois olivais de Trás-os-Montes. A importância dos coccinelídeos
como potenciais predadores de cochonilha-negra foi avaliada quer através do estabelecimento de
correlações entre a abundância de coccinelídeos e a abundância dos diferentes estados de desenvolvimento da praga, quer através da detecção de vestígios de cochonilha-negra no intestino dos
coccinelídeos por métodos serológicos (ELISA-indirecto). No total, identificaram-se 28 espécies de
coccínelídeos, das quais Chilocorus bipuswlatus, Scymnus (Pullus) med1terraneus. Scymnus (Pullus) subvillosus,
Scymnus (Scymnus) interruptus e Rhyzobius chrysomeloides foram as espécies mais representativas
no total dos olivais estudados. Relativamente à predação de cochontlha-negra, o segundo estado
ninfal foi o que apresentou maior número de correlações estatisticamente significativas com quatro
das cinco espécies de coccinelídeos estudadas, sendo potencialmente o estado de desenvolvimento mais predado. Por outro lado, os resultados obtidos através dos testes ELISA permitiram indicar
oito espécies de coccínelídeos (C. bipustulotus, E. quodrípustulotus. S. med/Lerroneus, N. bístgnotus, s.
subvíllosus, S. opetzi, S. interruptus e R. chrysomeloides) como potenciais predadores de cochonilha-negra. Os resultados obtidos apontam para o grande interesse destes insectos na limitação natural
da cochonilha-negra no olival
Association between urinary sodium excretion and body fat in school-aged children: Insights from the ARIA Study
Childhood obesity has been associated with increased sodium intake. Nonetheless, evidence linking sodium intake to Body Mass Index (BMI) and Body Fat Mass Percentage (%BF) remains limited, especially in the pediatric age group. Therefore, this study aims to investigate whether there is an association between 24 h urinary sodium excretion with BMI and %BF in a sample group of children from the ARIA study. This cross-sectional analysis included 303 children aged 7 to 12 from across 20 public schools in Porto, Portugal. Weight and %BF were assessed using the Tanita (TM) BC-418 Segmental Body Analyzer. Children's Total Energy Intake (TEI) was estimated through a single 24 h Recall Questionnaire, and urinary sodium and potassium excretion was estimated by a 24 h urine collection. The association of %BF and BMI with 24 h sodium excretion was estimated by a binary logistic regression adjusted for sex, age, physical activity, total energy intake, parental education, and 24 h urinary excreted potassium. There was a significant positive association between higher levels of urinary sodium excretion and higher %BF values, even after adjusting for confounders. However, the same was not observed for BMI. Our findings suggest that higher sodium intake is associated with higher values of %BF among children, regardless of TEI and potassium intake
The one-dimensional XXZ model with long-range interactions
The one-dimensional XXZ model (s=1/2, N sites) with uniform long-range
interactions among the transverse components of the spins is considered. The
Hamiltonian of the model is explicitly given by
where the
are half the Pauli spin matrices. The model is exactly solved by
applying the Jordan-Wigner fermionization, followed by a Gaussian
transformation. In the absence of the long-range interactions (I=0), the model,
which reduces to the isotropic XY model, is known to exhibit a second-order
quantum phase transition driven by the field at zero temperature. It is shown
that in the presence of the long-range interactions (I different from 0) the
nature of the transition is strongly affected. For I>0, which favours the
ordering of the transverse components of the spins, the transition is changed
from second- to first-order, due to the competition between transverse and xy
couplings. On the other hand, for I<0, which induces complete frustration of
the spins, a second-order transition is still present, although the system is
driven out of its usual universality class, and its critical exponents assume
typical mean-field values.Comment: 5 pages, 1 figure, presented at ICM2000, to be published in the
Proceedings (Journal of Magnetism & Magnetic Materials
Arterial Health Markers in Relation to Behavior and Cognitive Outcomes at School Age
BACKGROUND:Impaired arterial health is associated with a decline in cognitive function and psychopathology in adults. We hypothesized that these associations originate in early life. We examined the associations of blood pressure, common carotid artery intima media thickness, and carotid distensibility with behavior and cognitive outcomes during adolescence. METHODS AND RESULTS: This study was embedded in the Dutch Generation R Study, a population-based prospective cohort study from early fetal life onwards. Blood pressure, carotid intima media thickness, and carotid distensibility were measured at the age of 10 years. At the age of 13 years, total, internalizing and externalizing problems and attention-deficit hyperactivity disorder symptoms were measured using the parent-reported Child Behavior Checklist (CBCL/6-18), autistic traits were assessed by the Social Responsiveness Scale, and IQ was assessed using the Wechsler Intelligence Scale for Children-Fifth Edition. A 1-SD score higher mean arterial pressure was associated with lower odds of internalizing problems (odds ratio [OR], 0.92 [95% CI, 0.85-0.99]). However, this association was nonsignificant after correction for multiple testing. Carotid intima media thickness and carotid distensibility were not associated with behavior and cognitive outcomes at 13 years old. CONCLUSIONS: From our results, we cannot conclude that the associations of blood pressure, carotid intima media thickness, and carotid distensibility at age 10 years with behavior and cognitive outcomes are present in early adolescence. Further follow-up studies are needed to identify the critical ages for arterial health in relation to behavior and cognitive outcomes at older ages.</p
Evaluation of composts and liming materials in the phytostabilization of a mine soil using perennial ryegrass
A microcosm experiment was carried out to evaluate the effects of municipal solid waste
compost (MSWC) or garden waste compost (GWC), and liming materials in the rehabilitation
of a soil affected by mining activities, and to study the use of perennial ryegrass (Lolium
perenne L.) for phystostabilization. The performance of the amendments was assessed by
soil chemical parameters, total and bioavailable metals (Cu, Pb and Zn), soil enzymatic
activities, and plant relative growth and mineral composition. In general, both composts
corrected soil acidity and increased the total organic matter content of the soil, although
with a better performance in the case of MSWC, especially when considering total N and
available P and K levels in the amended soil. The application of both composts and liming
materials led to a decrease in the mobile fractions of Cu, Pb and Zn, but mobilisable fractions
of Cu and Zn increased with MSWC application. Plant biomass increased more than three
times in the presence of 50 Mg MSWC ha−1 and with the combined use of 25 or 50 Mg MSWC
ha−1 and CaO, but no significant differences were observed when GWC was applied. Plant
tissue analysis showed that the treatments did not significantly reduce Cu, Pb and Zn
uptake by the plant. Dehydrogenase, and the enzymes related to the N-cycle, urease and
protease, had increased activities with increasing MSWC application rate. Conversely, the
enzymatic activities of both enzymes related to the C-cycle, cellulase and β-glucosidase,
were only positively affected by GWC application, a compost obtained from raw materials
rich in C. Principal component analyses evidenced this clear separation between the effect
of MSWC on soil enzymes related to the N-cycle and of GWC on soil enzymes related to the
C-cycle. This study indicates that MSWC (50 Mg ha−1, limed or unlimed) can be used
successfully in the remediation of a highly acidic metal-contaminated soil, allowing the
establishment of perennial ryegrass
Organic residues as immobilizing agents in aided phytostabilization: (I) Effects on soil chemical characteristics
A greenhouse experiment was conducted to evaluate the effect of three different organic residues, sewage
sludge (SS), municipal solid waste compost (MSWC), and garden waste compost (GWC), as immobilizing
agents in aided phytostabilization of a highly acidic metal-contaminated soil, affected by mining
activities, using perennial ryegrass (Lolium perenne L.). The organic residues were applied at 25, 50 and
100 Mg ha 1 (dry weight basis), and their effects on soil chemical characteristics and on relative plant
growth and metal concentrations were assessed. All the organic residues tested immobilized Cu, Pb
and Zn, decreasing their mobile fractions. This was corroborated by negative correlations obtained
between mobile Cu, Pb and Zn and other soil chemical characteristics, which rose as a consequence of
the amendments applied (i.e., pH, electrical conductivity, organic matter, nitrogen content, available P
and available K), and by the multivariate exploratory techniques performed that showed an inverse correlation
between these groups of variables. The greatest increase in ryegrass relative growth (more than
three times) was obtained in the presence of 50 Mg MSWC ha 1, followed by SS at the same application
dosage. GWC did not contribute to an increase in shoot growth, due to its small capacity to correct soil
acidity and to supply essential macronutrients (N, P, K). No extractant was able of demonstrating by a
linear correlation the uptake of Cu, Pb and Zn by ryegrass. This plant was therefore not a good ‘‘indicator”
of Cu, Pb and Zn availability in the soil. The results obtained in this study suggest that ryegrass can be
used in aided phytostabilization for this type of mine contaminated soils and that MSWC, and to a minor
extent SS, applied at 50 Mg ha 1, were effective in the in situ immobilization of metals, improving soil
chemical properties and leading to a large increase in plant biomas
Abundance and diversity of Heteropteran species in portuguese olive groves
The olive tree canopy is a habitat for phytophagous and predaceous Heteropteran specimens
whose biodiversity is important to be characterized. The aim of this world was to study the abundance
and diversity of Heteropteran specimens in Portuguese olive groves with different plant
protection systems (conventional. integrated protection and organic farming groves). Therefore,
data were obtained in olive groves located in the main olive Portuguese regions (Alto Alentejo and Trás-os-Montes). Sampling occurred in 1999, 2000, 2002 and 2003 and samples were obtained
through the beating technique, on a weekly or fortnight basis from March to November of each
year. The captured heteropteran specimens were identified to family level and, when possible, to
genera or species level. Experimental results showed that specimens belonged to six families that
were, for order of importance: Anthocoridae, Miridae. Lygaeidae, Tingidae, Penlalomidae and
Nabidae. Beneficial predaceous specimens like AntiJocoris sp. and Deraeocoris lutenscens
(Schilling, 1837) were the most abundant of the Anthocoridae and Miridae families, respectively.
These families were more abundant from the beginning to the middle of June which coincided with
the antophagou5 larval stage of the olive moth, Prays oleae (Bernard)
Biological invasion of Corythucha ciliata in green urban spaces in Portugal: a niche modeling approach using maximum entropy
Corythucha ciliata (Hemiptera: Tingidae) é um inseto nativo da América do Norte que foi introduzido
na Europa, pela Itália, em 1964. Desde então tem se expandido por toda a Europa, desconhecendo-se a
data de chegada e a sua área de distribuição em Portugal. Esta importante praga invasora alimenta-se na
face inferior das folhas de plátano, uma das mais importantes árvores ornamentais nos espaços verdes
urbanos em Portugal, causando senescência prematura e eventualmente morte, em casos de infestações
severas consecutivas. A modelação de nicho está se tornando uma ferramenta cada vez mais importante
na gestão de invasões biológicas, tanto antes como depois da introdução do organismo invasor. Neste
estudo, o software MaxEnt (máxima entropia) foi usado na modelação da distribuição invasiva potencial de
Corythucha ciliata em Portugal, a partir de um conjunto de variáveis ambientais e de dados de presença do
inseto, obtidos a partir da observação de folhas de plátanos amostrados por todo o país. De acordo com o
melhor modelo gerado pelo MaxEnt, as áreas de maior adequabilidade potencial à invasão de Corythucha
ciliata encontram-se no norte de Portugal apresentando o sul e as regiões de maior altitude do norte e centro
adequabilidade reduzida ou nula. Observações laboratoriais da biologia de Corythucha ciliata aliadas aos
registos de ausência em várias localidades do sul de Portugal e ocorrência predominante na metade norte de
Espanha suportam o modelo desenvolvido. Porém, a validação do modelo requer futuras prospecções nas
áreas de reduzida adequabilidade e onde a praga se encontrava virtualmente ausente no momento em que
foi realizada a amostragem. Os modelos de adequabilidade podem ser usados como ferramenta auxiliar na
tomada de decisão no que concerne à gestão dos espaços verdes
Efeito da intensificação cultural na diversidade de Araneae no solo dos olivais da região Alentejo
O cultivo de Olea europaea é praticado em toda a região mediterrânica sendo
que na Península Ibérica constitui um recurso agrícola de grande importância
económica. Em Portugal, o Alentejo é o principal produtor de azeite. As aranhas, um
grupo de artrópodes muito importante nos ecossistemas agrícolas, podem ser úteis
como indicadores biológicos de práticas culturais. Este trabalho tem como objectivo
contribuir para caracterizar a comunidade de aranhas associada ao solo do olival e
avaliar o efeito da intensificação cultural nesta comunidade.
As aranhas foram amostradas mensalmente durante 2010 em quatro olivais na
região de Serpa (Alentejo, Portugal). Recorreu-se à colocação de armadilhas de queda
no solo (pitfall) durante um período de 24 horas, em 25 árvores seleccionadas
aleatoriamente, para a inventariação das aranhas do solo. Os artrópodes foram
levados para o laboratório, triados e identificados. No caso das aranhas estas foram
identificadas até à família recorrendo a chaves de identificação. Na análise dos dados
aplicou-se um tipo de análise multivariada (ACP) e o software Estimates foi utilizado
para o cálculo das curvas de acumulação de famílias.
No total, 175 amostras foram recolhidas, nas quais se identificaram 23 famílias.
Destas, as mais abundantes foram Agelenidae e Lycosidae no olival tradicional,
Agelenidae e Linyphiidae no olival intensivo, Lycosidae e Gnaphosidae no olival em
modo de produção biológico e Titanoecidae e Agelenidae no olival em sebe
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