10,363 research outputs found
Spin-dependent beating patterns in thermoelectric properties: Filtering the carriers of the heat flux in a Kondo adatom system
We theoretically investigate the thermoelectric properties of a
spin-polarized two-dimensional electron gas hosting a Kondo adatom hybridized
with an STM tip. Such a setup is treated within the single-impurity Anderson
model in combination with the atomic approach for the Green's functions. Due to
the spin dependence of the Fermi wavenumbers the electrical and thermal
conductances, together with thermopower and Lorenz number reveal beating
patterns as function of the STM tip position in the Kondo regime. In
particular, by tuning the lateral displacement of the tip with respect to the
adatom vicinity, the temperature and the position of the adatom level, one can
change the sign of the Seebeck coefficient through charge and spin. This opens
a possibility of the microscopic control of the heat flux analogously to that
established for the electrical current
Attraction of Planococcus ficus males to racemic and chiral pheromone baits: flight activity and bait longevity
The vine mealybug (VM), Planococcus ficus (Signoret), is a worldwide pest
and affects mainly grapevine and figs. In Israel, (S)-lavandulyl senecioate
[(S)-LS] and (S)-lavandulyl isovalerate [(S)-LI] were identified from
VM reared for several generations on potato sprouts, when compared
with the identification of only (S)-LS from feral females. Racemic lavandulyl
senecioate (LS) can be used for fieldwork because the unnatural
enantiomer is benign and does not affect the activity of the pheromone.
Lures loaded with 200 lg of LS remained active for 24 weeks but it is
recommended to replace lures after 12 weeks to preserve constant and
high attractiveness. Delta sticky traps, baited with 50 or 200 lg of LS
were used to determine the daily flight pattern and the seasonal flight
activity including vine plant infestation. A positive correlation between
peak mealybug density and male capture was observed strengthening
the usefulness of the pheromone traps for monitoring the pest. Addition
of racemic or the two enantiomers of lavandulyl isovalerate (LI) to LS
decreased the capture of VM males. The level of inhibition varied during
2003–2004. Both enantiomers of LI displayed the same antagonistic
activity. Addition of (S)-lavandulol to the pheromone resulted in shutdown
of the traps. Inhibition by the antipode, (R)-lavandulol, was moderate
indicating a certain degree of chiral discriminatio
Desenvolvimento do feijoeiro sob o uso de biofertilizante e adubação mineral.
A produção intensiva de alimentos exige manejo adequado do solo para garantir a produtividade e a sustentabilidade ambiental. Uma das alternativas é a utilização de resíduos orgânicos no desenvolvimento das culturas, diminuindo a dependência de adubos minerais. Com o objetivo de avaliar o desenvolvimento da cultura de feijão (Phaseolus vulgaris L.), utilizando biofertilizante e adubação mineral, conduziu-se o experimento com seis tratamentos dispostos ao acaso, em esquema fatorial, em quatro blocos, com parcelas de 8,0 x 5,0 m. Os tratamentos sob solo cultivado com a cultura de feijão caracterizaram-se como: com e sem biofertilizante (CB e SB, respectivamente) e para a adubação mineral foram utilizadas a dose recomendada no plantio, ½ dose de adubação e sem adubação mineral (AM, 1/2AM, SAM). Adotaram-se práticas culturais convencionais para o preparo inicial do solo, e em seguida foi efetuada a aplicação de biofertilizante de origem bovina na dosagem de 100 m3 ha-1, com antecedência de três meses da semeadura. Foram avaliados os parâmetros massa da matéria seca acumulada na parte aérea da planta, área foliar e produtividade da cultura. Os resultados mostraram semelhanças entre as características analisadas, obtendo-se melhor desenvolvimento à cultura que recebeu biofertilizante
Evaluation of thermal comfort, physiological and seminal parameters of buffaloes kept in artificial insemination center under tropical climate.
Proceedings of the 28th Annual Meeting of the Brazilian Embryo Technology Society (SBTE), August 14 to 17th, 2014, Natal, RN, Brazil. Abstracts
Molecular detection of avian gyrovirus type 2 (AGV2) in specific pathogen free (SPF) chickens housed on commercial broiler litter.
Projeto/Plano de Ação: 02.11.01.012
Kairomonal response of the parasitoid Anagyrus spec. nov. near pseudococci to the sex pheromone of the vine mealybug
The occurrence of a kairomonal response of the parasitoid
Anagyrus
spec. nov. near
pseudococci
(Hymenoptera: Encyrtidae) to (+)-(1
R,
3
R
)-
cis
-2,2-dimethyl-3-isopropenyl-cyclobutanemethanol
acetate (PcA, namely, planococcyl acetate) and (
S
)-(+)-lavandulyl senecioate (LS), the respective
female sex pheromones of its hosts, the citrus mealybug,
Planococcus citri
(Risso) and the vine mealybug,
Planococcus ficus
(Signoret) (Homoptera: Pseudococcidae) was investigated. Attraction to the
pheromones was tested by employing pheromone traps in field trials and by static air olfactometer
bioassays in the laboratory. Female wasps showed a significant response to LS, in both field and
olfactometer experiments. No significant response was registered to the sex pheromone of
P. citri.
Despite the similarity between the structures of LS and its analogue (
S
)
-
(+)-lavandulyl isovalerate
(LI), no significant response to the latter compound was observed. It seems that differences between
the structures of the carboxylate moiety of the respective molecules (LS and LI) markedly affect the
kairomonal attractiveness to the parasitoid. The kairomonal response of
Anagyrus
spec. nov. near
pseudococci
was neither influenced by the host habitat nor by the host species on which it developed. This suggested
innate behaviour of
Anagyrus
spec. nov. near
pseudococci
, possibly derived from evolutionary relationships
between the parasitoid and
P. ficus
. The practical implications of the results are discussed
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