1,008 research outputs found
Efeito da fertilização mineral fosfatada na partição das formas de fósforo num Regossolo
PTDC/AGR-PRO/112127/2009:
Fitodisponibilidade e riscos ambientais do fósforo aplicado por via de chorumes de pecuária intensiva em solos portugueses.O conhecimento da partição do P no solo por diferentes formas com distinta labilidade, ajuda a perceber a dinâmica do P
não só relativamente à sua fitodisponibilidade, como também a riscos de transferência para as águas com consequências
negativas na eutrofização. Neste trabalho, efetuou-se a caracterização das formas de P presentes num Regossolo e, após
uma adubação mineral fosfatada, avaliou-se o seu efeito sobre a fitodisponibilidade e partição das formas de fósforo. Os resultados
obtidos contribuirão para uma melhor gestão do P no solo.FC
Anomalous Stark Shifts in Single Vertically Coupled Pairs of InGaAs Quantum Dots
Vertically coupled Stranski Krastanow QDs are predicted to exhibit strong
tunnelling interactions that lead to the formation of hybridised states. We
report the results of investigations into single pairs of coupled QDs in the
presence of an electric field that is able to bring individual carrier levels
into resonance and to investigate the Stark shift properties of the excitons
present. Pronounced changes in the Stark shift behaviour of exciton features
are identified and attributed to the significant redistribution of the carrier
wavefunctions as resonance between two QDs is achieved. At low electric fields
coherent tunnelling between the two QD ground states is identified from the
change in sign of the permanent dipole moment and dramatic increase of the
electron polarisability, and at higher electric fields a distortion of the
Stark shift is attributed to a coherent tunnelling effect between the ground
state of the upper QD and the excited state of the lower QD.Comment: Conference paper for QD2004 3 figure
Fertilizantes orgânicos : efeito na fertilidade do solo e na produção de azevém
Fertilizantes orgânicos : efeito na fertilidade do solo e na produção de azevém
Ciclo do fósforo em agroecossistemas: Efeito da fertilização fosfatada com adubos minerais ou com resíduos orgânicos de pecuária
Comunicação oral da qual só está disponível o resumo.Ciclo do fósforo em agroecossistemas: Efeito da fertilização fosfatada com
adubos minerais ou com resíduos orgânicos de pecuária.Trabalho financiado pelo projeto FCT PTDC/AGRPRO/
112127/2009, “Assessment of phosphorus bioavailability from animal manures
applied to Portuguese soils and site vulnerability to phosphorus losses”, 2011-2013
A Comparison between Dual Phase Steel and Interstitial Free Steel Due To the Springback Effect
International audienceThis is a study of the springback effect on two kinds of high strength steel, which are: dualphase and interstitial free, currently used as feedstock in the production of vehicles. The mechanical characterization of the springback effect was performed by means of a mechanical conformation test, called three-point air bending, performed by adapting it to the unconstrained cylindrical bending test. It was also evaluated the mechanical properties of the material defined by the tensile test in order to determine its tensile strength, yield strength, and elongation. Furthermore, it was performed a microstructural characterization of advanced steels by identifying and quantifying the present phases in coexistence by means of digital image processing. The results indicate that the springback effect in the dual-phase steel has the highest springback rates due to its high mechanical strength, and it causes a decrease in the aspect ratio of the grains that suffered mechanical conformation attempting to return it to its original form. On the other hand, the springback effect has the lowest rates, and the change in aspect ratio depends only on the interstitial free steel elongation capacity due to its lower mechanical strength
Spirometry And Volumetric Capnography In Lung Function Assessment Of Obese And Normal-weight Individuals Without Asthma
To analyze and compare lung function of obese and healthy, normal-weight children and adolescents, without asthma, through spirometry and volumetric capnography. Methods: Cross-sectional study including 77 subjects (38 obese) aged 5-17 years. All subjects underwent spirometry and volumetric capnography. The evaluations were repeated in obese subjects after the use of a bronchodilator. Results: At the spirometry assessment, obese individuals, when compared with the control group, showed lower values of forced expiratory volume in the first second by forced vital capacity (FEV1/FVC) and expiratory flows at 75% and between 25 and 75% of the FVC (p <0.05). Volumetric capnography showed that obese individuals had a higher volume of produced carbon dioxide and alveolar tidal volume (p <0.05). Additionally, the associations between dead space volume and tidal volume, as well as phase-3 slope normalized by tidal volume, were lower in healthy subjects (p <0.05). These data suggest that obesity does not alter ventilation homogeneity, but flow homogeneity. After subdividing the groups by age, a greater difference in lung function was observed in obese and healthy individuals aged >11 years (p <0.05). Conclusion: Even without the diagnosis of asthma by clinical criteria and without response to bronchodilator use, obese individuals showed lower FEV1/FVC values and forced expiratory flow, indicating the presence of an obstructive process. Volumetric capnography showed that obese individuals had higher alveolar tidal volume, with no alterations in ventilation homogeneity, suggesting flow alterations, without affecting lung volumes. © 2017 Sociedade Brasileira de Pediatria
Animal manures applied to soil: phosphorus bioavailability, losses to water and erosion
Comunicação oral da qual só está disponível o resumo.Phosphorus (P) is a non renewable resource which highlights the
significance of developing and using alternative sources of P for a sustainable
agriculture. Animal manure is an option but its application to soils to meet crop
nitrogen needs requires careful management practices to minimize freshwater
eutrophication. The aim of this work was to evaluate the partitioning of applied P
between plant uptake, losses to water, and erosion losses when using different
animal manures and a mineral P fertilizer. A field trial was conducted at an erosion
experimental station. The treatments were: Control (0 kg P/ha); cattle manure; solid
fraction of pig and duck slurry and superphosphate, each applied at a rate of 50 kg
P/ha after Lolium sp was sown. Soil samples from each trial were collected over the
9-month study and the water extractable soil P determined. It was found that
desorption of P from all additions rapidly increased soon after P application (2
weeks). After that water extractable soil P remained fairly constant. While duck
slurry desorbed the largest concentration of P, all sources have the potential to
desorb P that could accelerate eutrophication. Plant uptake of P was greater with
cattle manure added and released the least amount of P to water compared with the
other sources of P. The partitioning of applied P between plant uptake and losses to
runoff and sediments ranged between 5-12 % with the higher values in Duck
treatment. Animal manures significantly increased soil Olsen-P, plant production and P
uptake relative to mineral fertilizer. Animal manures can be considered as a source of
available P nevertheless to avoid eutrophication risks increase plant P use efficiency is also
important
Loop bounds on non-standard neutrino interactions
We reconsider the bounds on non-standard neutrino interactions with matter
which can be derived by constraining the four-charged-lepton operators induced
at the loop level. We find that these bounds are model dependent. Naturalness
arguments can lead to much stronger constraints than those presented in
previous studies, while no completely model-independent bounds can be derived.
We will illustrate how large loop-contributions to four-charged-lepton
operators are induced within a particular model that realizes gauge invariant
non-standard interactions and discuss conditions to avoid these bounds. These
considerations mainly affect the constraint on the
non-standard coupling strength \eps_{e\mu}, which is lost. The only
model-independent constraints that can be derived are .
However, significant cancellations are required in order to saturate this
bound.Comment: Minor changes, version to be published in JHEP. 17 pages, 3 Axodraw
figures, REVTeX
Effect of panretinal photocoagulation on the peripapillary retinal nerve fiber layer in diabetic retinopathy patients
OBJECTIVES: To determine the effect of panretinal photocoagulation (PRP) on the peripapillary retinal nerve fiber layer (RNFL) in nonglaucomatous patients with proliferative diabetic retinopathy (PDR). METHODS: This is a prospective, single center, observational study. Thirty-eight eyes of 26 diabetic patients underwent PRP for proliferative diabetic retinopathy. Peripapillary RNFL thickness was measured using scanning laser polarimetry (SLP) with variable corneal compensation (GDx VCC; by Carl Zeiss Meditec, Dublin, CA) and spectral-domain optical coherence tomography (OCT) (Heidelberg Spectralis, Carlsbad, USA) at baseline and 12 months after PRP was performed. RESULTS: Thirty-eight eyes of 26 patients (15 female) with a mean age of 53.7 years (range 26 to 74 years) were recruited. No significant difference was found among all RNFL thickness parameters tested by GDx VCC software (p=0.952, 0.464 and 0.541 for temporal-superior-nasal-inferior-temporal (TSNIT) average, superior average, inferior average, respectively). The nerve fiber indicator (NFI) had a nonsignificant increase (p=0.354). The OCT results showed that the average RNFL thickness (360o measurement) decreased nonsignificantly from 97.2 mm to 96.0 mm at 1 year post-PRP (p=0.469). There was no significant difference when separately analyzing all the peripapillary sectors (nasal superior, temporal superior, temporal, temporal inferior, nasal inferior and nasal thickness). CONCLUSION: Our results suggest that PRP, as performed in our study, does not cause significant changes in peripapillary RNFL in diabetic PDR patients after one year of follow-up
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