634 research outputs found
The positive response in grape secondary metabolites under controlled stresses: a review
Grapevine is cultivated worldwide with great economic importance. In recent years, our knowledge of the physiological and molecular basis of berry quality regulation has substantially increased. Abiotic and biotic stresses, such as deficit irrigation, low temperature, light/UV and microbes, to a certain extent, could improve grape berry quality by enhancing flavor metabolites, colorization or aroma compounds. This review summarizes recent data related to the stress of grape berry development, with special emphasis on secondary metabolism and its response to stresses. A full understanding of how grape berry metabolism responds to different stresses is important to improve the biochemical qualities of grapes and resultant products, such as wine in practice
Effects of Termites on Soil pH and Its Application for Termite Control in Zhejiang Province, China
Soil dwelling termites dig nests in the ground that have a significant impact on the soil environment. Activities of termites can result in accumulation of organic matter and enrichment of nutrients and minerals in the soil. Samples from the nest/surrounding soils of two termite species (Odontotermes formosanus (Shiraki) and Reticulitermes flaviceps (Oshima)) and termite non-invaded soils in the seawall of the Qiantang River, Zhejiang Province, China were collected and analysed for soil pH. The results show that the observed termites prefer an acidic environment and that their activities elevate the pH of termite mound soil compared with surrounding soil. Considering the differences in the distribution areas, termite species, and properties of termite mounds and surrounding soils, this paper also examines the literature concerning the effects of termites on soil pH. After summarizing the pH of the termite survival soil environment, the feasibility of termite control by modifying the soil pH is addressed. Finally, some topics for future research are discussed
A preliminary study on the monitoring of mixed venous oxygen saturation through the left main bronchus
INTRODUCTION: The study sought to assess the feasibility and accuracy of measuring mixed venous oxygen saturation (SvO(2)) through the left main bronchus (SpO(2trachea)) METHODS: Twenty hybrid pigs of each sex were studied. After anesthesia, a Robertshaw double-lumen tracheal tube with a single-use pediatric pulse oximeter attached to the left lateral surface was introduced toward the left main bronchus of the pig by means of a fibrobronchoscope. Measurements of SpO(2trachea )and oxygen saturation from pulmonary artery samples (SvO(2blood)) were performed with an intracuff pressure of 0 to 60 cmH(2)O. After equilibration, hemorrhagic shock was induced in these pigs by bleeding to a mean arterial blood pressure of 40 mmHg. With the intracuff pressure maintained at 60 cmH(2)O, SpO(2trachea )and SvO(2blood )were obtained respectively during the pre-shock period, immediately after the onset of shock, 15 and 30 minutes after shock, and 15, 30, and 60 minutes after resuscitation. RESULTS: SpO(2trachea )was the same as SvO(2blood )at an intracuff pressure of 10, 20, 40, and 60 cmH(2)O, but was reduced when the intracuff pressure was zero (p < 0.001 compared with SvO(2blood)) in hemodynamically stable states. Changes of SpO(2trachea )and SvO(2blood )corresponded with varieties of cardiac output during the hemorrhagic shock period. There was a significant correlation between the two methods at different time points. CONCLUSION: Measurement of the left main bronchus SpO(2 )is feasible and provides similar readings to SvO(2blood )in hemodynamically stable or in low saturation states. Tracheal oximetry readings are not primarily derived from the tracheal mucosa. The technique merits further evaluation
Three-dimensional potential energy surface for fission of U within covariant density functional theory
We have calculated the three-dimensional potential energy surface (PES) for
the fission of compound nucleus U using the covariant density
functional theory with constraints on the axial quadrupole and octupole
deformations as well as the nucleon number in the neck
. By considering the additonal degree of freedom , coexistence of the
elongated and compact fission modes is predicted for . Remarkably, the PES becomes very shallow across a large range of
quadrupole and octupole deformations for small , and consequently, the
scission line in plane will extend to a shallow band,
which leads to a fluctuation for the estimated total kinetic energies by
several to ten MeV and for the fragment masses by several to about ten
nucleons
Source attack of decoy-state quantum key distribution using phase information
Quantum key distribution (QKD) utilizes the laws of quantum mechanics to
achieve information-theoretically secure key generation. This field is now
approaching the stage of commercialization, but many practical QKD systems
still suffer from security loopholes due to imperfect devices. In fact,
practical attacks have successfully been demonstrated. Fortunately, most of
them only exploit detection-side loopholes which are now closed by the recent
idea of measurement-device-independent QKD. On the other hand, little attention
is paid to the source which may still leave QKD systems insecure. In this work,
we propose and demonstrate an attack that exploits a source-side loophole
existing in qubit-based QKD systems using a weak coherent state source and
decoy states. Specifically, by implementing a linear-optics
unambiguous-state-discrimination measurement, we show that the security of a
system without phase randomization --- which is a step assumed in conventional
security analyses but sometimes neglected in practice --- can be compromised.
We conclude that implementing phase randomization is essential to the security
of decoy-state QKD systems under current security analyses.Comment: 12 pages, 5 figure
The DWT Power Spectrum of the two-degree Field Galaxy Redshift Survey
The power spectrum of the two-degree Field Galaxy Redshift Survey (2dFGRS)
sample is estimated with the discrete wavelet transform (DWT) method. The DWT
power spectra within Mpc are measured for three
volume-limited samples defined in connective absolute magnitude bins , and . We show that the DWT power spectrum
can effectively distinguish CDM models of and
. We adopt maximum likelihood method to perform three-parameter
fitting with bias parameter , pairwise velocity dispersion and
redshift distortion parameter to the measured DWT
power spectrum. Fitting results denotes that in a universe the
best fitted given by the three samples are consistent in the range
, and the best fitted are ,
and km/s for the three samples, respectively.
However in the model of , our three samples give very different
values of . We repeat the fitting by using empirical formula of
redshift distortion. The result of the model of low is still poor,
especially, one of the best value is as large as km/s. The
power spectrum of 2dFGRS seems in disfavor of models with low amplitude of
density fluctuations.Comment: 11 pages, 9 figures. submitted to MNRAS. submitted to MNRA
Experimental Free-Space Distribution of Entangled Photon Pairs over a Noisy Ground Atmosphere of 13km
We report free-space distribution of entangled photon pairs over a noisy
ground atmosphere of 13km. It is shown that the desired entanglement can still
survive after the two entangled photons have passed through the noisy ground
atmosphere. This is confirmed by observing a space-like separated violation of
Bell inequality of . On this basis, we exploit the distributed
entangled photon source to demonstrate the BB84 quantum cryptography scheme.
The distribution distance of entangled photon pairs achieved in the experiment
is for the first time well beyond the effective thickness of the aerosphere,
hence presenting a significant step towards satellite-based global quantum
communication.Comment: 4 pages, 3 figure
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