98 research outputs found
On the V-DE Construction in Mandarin Chinese
The paper proposes a novel classification and analysis of the V-DE construction in Mandarin Chinese. On this proposal, the V-DE construction is divided into two types, predicative and non-predicative. The predicative type can be further divided into entity-predicative V-DE constructions and eventuality-predicative V-DE constructions. With respect to the analysis of the V-DE construction, the paper identifies four different structures. It points out that the de-part (i.e. the part after and marked by 得-de) in most V-DE constructions is a clause with or without an overt subject. Moreover, with respect to the cases where the de-part has an overt NP that can be interpreted as the Patient argument of the verb before -de and at the same time is semantically compatible with the VP or AP in the de-part, the paper proposes that the overt NP in such cases is syntactically the subject of the de-clause and syntactically is not the direct object of V-DE or the verb before -de. Finally, when the de-part of an entity-predicative V-DE construction has an overt NP between -de and the predicate of the de-clause, the AP or VP of the de-part generally needs to be predicated of the overt NP in the de-part. This constraint, however, can be occasionally relaxed to allow for a pragmatically-inducted interpretation when both of the following conditions are met: (i) the de-part is a well-formed clause in both form and meaning and (ii) the pragmatically-induced interpretation is pragmatically plausible
Evidence of a Massive Black Hole Companion in the Massive Eclipsing Binary V Puppis
Up to now, most stellar-mass black holes were discovered in X-ray emitting
binaries, in which the black holes are formed through a common-envelope evolu
tion. Here we give evidence for the presence of a massive black hole candidate
as a tertiary companion in the massive eclipsing binary V Puppis. We found that
the orbital period of this short-period binary (P=1.45 days) shows a periodic
variation while it undergoes a long-term increase. The cyclic period
oscillation can be interpreted by the light-travel time effect via the presence
of a third body with a mass no less than 10.4 solar mass. However, no spectral
lines of the third body were discovered indicating that it is a massive black
hole candidate. The black hole candidate may correspond to the weak X-ray
source close to V Puppis discovered by Uhuru, Copernicus, and ROSAT satellites
produced by accreting materials from the massive binary via stellar wind. The
circumstellar matter with many heavy elements around this binary may be formed
by the supernova explosion of the progenitor of the massive black hole. All of
the observations suggest that a massive black hole is orbiting the massive
close binary V Puppis with a period of 5.47 years. Meanwhile, we found the
central close binary is undergoing slow mass transfer from the secondary to the
primary star on a nuclear time scale of the secondary component, revealing that
the system has passed through a rapid mass-transfer stage.Comment: Accepted for publication in ApJ
A novel consortium of Lactobacillus rhamnosus and Streptococcus thermophilus for increased access to functional fermented foods
Background: The lactic acid bacterium Lactobacillus rhamnosus GG is the most studied probiotic bacterium with proven health benefits upon oral intake, including the alleviation of diarrhea. The mission of the Yoba for Life foundation is to provide impoverished communities in Africa increased access to Lactobacillus rhamnosus GG under the name Lactobacillus rhamnosus yoba 2012, world's first generic probiotic strain. We have been able to overcome the strain's limitations to grow in food matrices like milk, by formulating a dried starter consortium with Streptococcus thermophilus that enables the propagation of both strains in milk and other food matrices. The affordable seed culture is used by people in resource-poor communities. Results: We used S. thermophilus C106 as an adjuvant culture for the propagation of L. rhamnosus yoba 2012 in a variety of fermented foods up to concentrations, because of its endogenous proteolytic activity, ability to degrade lactose and other synergistic effects. Subsequently, L. rhamnosus could reach final titers of 1E+09 CFU ml(-1), which is sufficient to comply with the recommended daily dose for probiotics. The specific metabolic interactions between the two strains were derived from the full genome sequences of L. rhamnosus GG and S. thermophilus C106. The piliation of the L. rhamnosus yoba 2012, required for epithelial adhesion and inflammatory signaling in the human host, was stable during growth in milk for two rounds of fermentation. Sachets prepared with the two strains, yoba 2012 and C106, retained viability for at least 2 years. Conclusions: A stable dried seed culture has been developed which facilitates local and low-cost production of a wide range of fermented foods that subsequently act as delivery vehicles for beneficial bacteria to communities in east Africa.Peer reviewe
Does Speaking Two Dialects in Daily Life Affect Executive Functions? An Event-Related Potential Study
Whether using two languages enhances executive functions is a matter of debate. Here, we
take a novel perspective to examine the bilingual advantage hypothesis by comparing bidialect
with mono-dialect speakers’ performance on a non-linguistic task that requires executive
control. Two groups of native Chinese speakers, one speaking only the standard Chinese
Mandarin and the other also speaking the Southern-Min dialect, which differs from the
standard Chinese Mandarin primarily in phonology, performed a classic Flanker task. Behavioural
results showed no difference between the two groups, but event-related potentials
recorded simultaneously revealed a number of differences, including an earlier P2 effect in
the bi-dialect as compared to the mono-dialect group, suggesting that the two groups
engage different underlying neural processes. Despite differences in the early ERP component,
no between-group differences in the magnitude of the Flanker effects, which is an
index of conflict resolution, were observed in the N2 component. Therefore, these findings
suggest that speaking two dialects of one language does not enhance executive functions.
Implications of the current findings for the bilingual advantage hypothesis are discussed
Fine Tuning of the Lactate and Diacetyl Production through Promoter Engineering in Lactococcus lactis
Lactococcus lactis is a well-studied bacterium widely used in dairy fermentation and capable of producing metabolites with organoleptic and nutritional characteristics. For fine tuning of the distribution of glycolytic flux at the pyruvate branch from lactate to diacetyl and balancing the production of the two metabolites under aerobic conditions, a constitutive promoter library was constructed by randomizing the promoter sequence of the H2O-forming NADH oxidase gene in L. lactis. The library consisted of 30 promoters covering a wide range of activities from 7,000 to 380,000 relative fluorescence units using a green fluorescent protein as reporter. Eleven typical promoters of the library were selected for the constitutive expression of the H2O-forming NADH oxidase gene in L. lactis, and the NADH oxidase activity increased from 9.43 to 58.17-fold of the wild-type strain in small steps of activity change under aerobic conditions. Meanwhile, the lactate yield decreased from 21.15±0.08 mM to 9.94±0.07 mM, and the corresponding diacetyl production increased from 1.07±0.03 mM to 4.16±0.06 mM with the intracellular NADH/NAD+ ratios varying from 0.711±0.005 to 0.383±0.003. The results indicated that the reduced pyruvate to lactate flux was rerouted to the diacetyl with an almost linear flux variation via altered NADH/NAD+ ratios. Therefore, we provided a novel strategy to precisely control the pyruvate distribution for fine tuning of the lactate and diacetyl production through promoter engineering in L. lactis. Interestingly, the increased H2O-forming NADH oxidase activity led to 76.95% lower H2O2 concentration in the recombinant strain than that of the wild-type strain after 24 h of aerated cultivation. The viable cells were significantly elevated by four orders of magnitude within 28 days of storage at 4°C, suggesting that the increased enzyme activity could eliminate H2O2 accumulation and prolong cell survival
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