1,098 research outputs found
Hole spin polarization in GaAlAs:Mn structures
A self-consistent calculation of the electronic properties of GaAlAs:Mn
magnetic semiconductor quantum well structures is performed including the
Hartree term and the sp-d exchange interaction with the Mn magnetic moments.
The spin polarization density is obtained for several structure configurations.
Available experimental results are compared with theory.Comment: 4 page
Effect of prebiotic or probiotic supplementation and ileo rectal anastomosis on intestinal morphology of weaned piglets
Forty eight 21 days old piglets were used to compare the effect of prebiotic or probiotic supplementation and ileo rectal anastomosis on the morphology of the small intestine. Half of the piglets were maintained intact and the other half was subjected to an ileo rectal anastomosis (IRA). Each group of piglets received one of the following diets: 1) basal diet (C), 2) basal diet supplemented with a Xylo-oligosaccharide (XOS), 3) basal diet supplemented with a Saccharomyces cerevisiae (SC) and 4) basal diet supplemented with XOS and SC. Villus height was greatest with XOS and with XOS + SC, only in the ileum, as compared to controls. In the duodenum, crypt width was highest in the control group, but no significant differences were found in the jejunum and ileum. The IRA piglets had longer villi in the jejunum and shorter villi in the ileum. The crypt depth was greater in the duodenum and in the ileum of IRA piglets. Villus height/crypt depth was lower in the duodenum and in the ileum, in the IRA piglets. In conclusion, the XOS, but not the SC, moderately modified the intestinal morphology. The IRA modified the intestinal villus and crypt architecture but its consequence on the absorption of nutrients needs to be investigated
Novos Isolados De Trichoderma Antagônicos A Sclerotinia Sclerotiorum
Forty-nine isolates of Trichoderma from the Brazilian Midwest were evaluated for their antagonistic activity in vitro against Sclerotinia sclerotiorum (causal agent of white mold), which were then identified based on their nuclear ribosomal ITS sequences. Paired culture tests showed that all isolates exhibited some antagonism, with a maximum of 77% mycelial inhibition and complete inhibition of sclerotia production. Two isolates were found to be the most promising biocontrol agents, considering both antagonistic parameters (CEN1253 - T. koningiopsis and CEN1265 - T. brevicompactum). Five different species were identified: T. harzianum (23), T. spirale (9), T. koningiopsis (8), T. brevicompactum (7) and T. asperellum (2). These isolates are stored in the Embrapa Fungi Collection for Biological Control and the information obtained in the experiments will be incorporated into the database of biological assets within the genetic resources information system (Allele) and be made available for further studies. © 2016, Universidade Estadual de Campinas UNICAMP. All rights reserved.16
Characterization of the sedimentary record of the AD1755 tsunami in the Martinhal Holocene succession (Algarve, Portugal) Caracterização do registo sedimentar do tsunami de 1755, na sucessão holocénica do Martinhal (Algarve, Portugal)
This study addresses the Holocene sedimentary succession at Martinhal coastal lowland
(Algarve), a site recording the AD1755 Lisbon tsunami. Data on twenty-four short cores and sixteen
trenches, retrieved from both the literature and new field work were combined to improve the
stratigraphic resolution and lateral correlation of sedimentary units accumulated in this lowland.
Four fining-upward depositional sequences (S1 to S4) were identified, showing spatial variation with
maximum thickness - S1: 0-3 m; S2: 1.0-2.4 m; S3: 0.2-1.0 m; S4: 0.3-2.3 m. Sequences S1, S2 and S3
consist of medium to coarse yellow sands with levels rich in bioclasts that give place upsequence to
brown organic silt and clay. Sequences S1 to S3 testify to the progressive infilling of a small estuary,
coeval with the progressive development and changes in efficiency of a sandy barrier. The
uppermost sequence (S4) is clearly different and also shows contrast in facies at seaward and
landward locations. S4 comprises: 1) seaward (ESE), a basal subunit with boulders to pebbly gravels
and coarse to medium well sorted sands, interpreted as deposited by the AD1755 tsunami, covered
by an upper subunit comprising an alternation of well sorted white sands and brown silts,
interpreted as aeolian/washover and flood deposits; 2) upstream (WNW), alternating layers of
poorly sorted very coarse to medium sands and brown silts represent flood plain accretion and
channel infill within the lowland. Quartz OSL dating was done by measuring small aliquots in samples
from the AD1755 event-layer and large aliquots in samples from other deposits. The coarser and
more basal sediment of the AD1755 sediment yielded overestimated OSL ages due to partial
bleaching; at the top, and in finer sediment, and also in the more landward locations, OSL ages are
closer to the true age of this event. At this location, routine Quartz OSL dating using large aliquots
can give useful data on the burial ages for a variety of sediments, provided that the burial time
exceeds ca. 1 ky. In contrast, recent abrupt-event sediments should be dated by measuring small
aliquots or single grains to get a better control on partial bleaching effects on OSL results
Biochemical parameters of silver catfish (Rhamdia quelen) after transport with eugenol or essential oil of Lippia alba added to the water
The transport of live fish is a routine practice in aquaculture and constitutes a considerable source of stress to the animals. The addition of anesthetic to the water used for fish transport can prevent or mitigate the deleterious effects of transport stress. This study investigated the effects of the addition of eugenol (EUG) (1.5 or 3.0 mu L L-1) and essential oil of Lippia alba (EOL) (10 or 20 mu L L-1) on metabolic parameters (glycogen, lactate and total protein levels) in liver and muscle, acetylcholinesterase activity (AChE) in muscle and brain, and the levels of protein carbonyl (PC), thiobarbituric acid reactive substances (TBARS) and nonprotein thiol groups (NPSH) and activity of glutathione-S-transferase in the liver of silver catfish (Rhamdia quelen; Quoy and Gaimard, 1824) transported for four hours in plastic bags (loading density of 169.2 g L-1). The addition of various concentrations of EUG (1.5 or 3.0 mu L L-1) and EOL (10 or 20 mu L L-1) to the transport water is advisable for the transportation of silver catfish, since both concentrations of these substances increased the levels of NPSH antioxidant and decreased the TBARS levels in the liver. In addition, the lower liver levels of glycogen and lactate in these groups and lower AChE activity in the brain (EOL 10 or 20 mu L L-1) compared to the control group indicate that the energetic metabolism and neurotransmission were lower after administration of anesthetics, contributing to the maintenance of homeostasis and sedation status.Fundacao de Amparo a Pesquisa do Estado do Rio Grande do Sul (FAPERGS/PRONEX) [10/0016-8]; Conselho Nacional de Pesquisa e Desenvolvimento Cientifico (CNPq) [470964/2009-0]; Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES); CNPqinfo:eu-repo/semantics/publishedVersio
Pathogenic fungi: an unacknowledged risk at coastal resorts? New insights on microbiological sand quality in Portugal
Whilst the potential impact on beach users from microorganisms in water has received considerable attention, there has been relatively little investigation into microbial contaminants in sand. Thirty three beaches across Portugal were analyzed during a five year period (2006–2010) to determine the presence of yeasts, pathogenic fungi, dermatophytes, total coliforms, Escherichia coli and intestinal enterococci in sand.
Our results showed that 60.4% of the samples were positive for fungi and that 25.2% were positive for the bacterial parameters. The most frequent fungal species found were Candida sp. and Aspergillus sp., whereas intestinal enterococci were the most frequently isolated bacteria. Positive associations were detected among analyzed parameters and country-regions but none among those parameters and sampling period.
Regarding threshold values, we propose 15 cfu/g for yeasts, 17 cfu/g for potential pathogenic fungi, 8 cfu/g for dermatophytes, 25 cfu/g for E. coli, and 10 cfu/g for intestinal enterococci
Ferromagnetism and Canted Spin Phase in AlAs/GaMnAs Single Quantum Wells: Monte Carlo Simulation
The magnetic order resulting from a confinement-adapted
Ruderman-Kittel-Kasuya-Yosida indirect exchange between magnetic moments in the
metallic phase of a AlAs/Ga(1-x)Mn(x)As quantum well is studied by Monte Carlo
simulation. This coupling mechanism involves magnetic moments and carriers
(holes), both coming from the same Mn(2+) ions. It leads to a paramagnetic, a
ferromagnetic, or a canted spin phase, depending on the carrier concentration,
and on the magnetic layer width. It is shown that high transition temperatures
may be obtained.Comment: 7 figure
A linguistic characterization of Google+ posts across different social groups
FGW – Publications without University Leiden contrac
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