317 research outputs found
Does the Short Term Fluctuation of Mineral Element Concentrations in the Closed Hydroponic Experimental Facilities Affect the Mineral Concentrations in Cucumber Plants Exposed to Elevated CO\u3csub\u3e2\u3c/sub\u3e?
Aims
Studies dealing with plants’ mineral nutrient status under elevated atmospheric CO2concentration (eCO2) are usually conducted in closed hydroponic systems, in which nutrient solutions are entirely renewed every several days. Here, we investigated the contribution of the fluctuation of concentrations of N ([N]), P ([P]), and K ([K]) in nutrient solutions in this short period on their concentrations in cucumber plants exposed to different [CO2] and N levels. Methods
Cucumber (Cucumis sativus L.) plants were hydroponically grown under two [CO2] and three N levels. [N], [P], and [K] in nutrient solutions and cucumber plants were analyzed. Results
The transpiration rate (Tr) was significantly inhibited by eCO2, whereas Tr per plant was increased due to the larger leaf area. Elevated [CO2] significantly decreased [N] in low N nutrient solutions, which imposed an additional decrease in [N] in plants. [P] in nutrient solutions fluctuated slightly, so the change of [P] in plants might be attributed to the dilution effect and the demand change under eCO2. [K] in moderate and high N nutrient solutions were significantly decreased, which exacerbated the [K] decrease in plants under eCO2. Conclusions
The short-term fluctuation of [N] and [K] in nutrient solutions is caused by the asynchronous uptakes of N, K, and water under eCO2, which has an appreciable influence on [N] and [K] in plants besides the dilution effect. This defect of the closed hydroponic system may let us exaggerate the negative impact of eCO2 itself on [N] and [K] in plants
Gluon condensation, entanglement entropy and phase transition from holography
We consider the effect of gluon condensation on the holographic entanglement
entropy, which can be regarded as an order parameter of deconfinement phase
transition, in a holographic model at zero and finite temperature. At zero
temperature, it is found that phase transition can occur at critical length for
small gluon condensation. With the increase of gluon condensation, the critical
length becomes small which means the phase transition is easy to occur. The
difference of entanglement entropy between the connected and disconnected
surfaces is always negative at large gluon condensation, which indicates no
phase transition can occur in the deconfined phase as the subsystem size
varies. These results show that the gluon condensation is related to the phase
transition and contributes to deconfinement. At finite temperature, we can see
that the difference of the entanglement entropy is also always negative and the
system is always deconfined for vanishing and non-vanishing gluon condensation
in this model. These results confirm that the difference of entanglement
entropy is a useful probe to detect whether a system is in the confinement or
deconfinement phase
Interactive Effects of the CO\u3csub\u3e2\u3c/sub\u3e Enrichment and Nitrogen Supply on the Biomass Accumulation, Gas Exchange Properties, and Mineral Elements Concentrations in Cucumber Plants at Different Growth Stages
The concentration changes of mineral elements in plants at different CO2 concentrations ([CO2]) and nitrogen (N) supplies and the mechanisms which control such changes are not clear. Hydroponic trials on cucumber plants with three [CO2] (400, 625, and 1200 µmol mol−1) and five N supply levels (2, 4, 7, 14, and 21 mmol L−1) were conducted. When plants were in high N supply, the increase in total biomass by elevated [CO2] was 51.7% and 70.1% at the seedling and initial fruiting stages, respectively. An increase in net photosynthetic rate (Pn) by more than 60%, a decrease in stomatal conductance (Gs) by 21.2–27.7%, and a decrease in transpiration rate (Tr) by 22.9–31.9% under elevated [CO2] were also observed. High N supplies could further improve the Pn and offset the decrease of Gs and Tr by elevated [CO2]. According to the mineral concentrations and the correlation results, we concluded the main factors affecting these changes. The dilution effect was the main factor driving the reduction of all mineral elements, whereas Tr also had a great impact on the decrease of [N], [K], [Ca], and [Mg] except [P]. In addition, the demand changes of N, Ca, and Mg influenced the corresponding element concentrations in cucumber plants
Observation of Temperature-Induced Crossover to an Orbital-Selective Mott Phase in AFeSe (A=K, Rb) Superconductors
In this work, we study the AFeSe (A=K, Rb) superconductors
using angle-resolved photoemission spectroscopy. In the low temperature state,
we observe an orbital-dependent renormalization for the bands near the Fermi
level in which the dxy bands are heavily renormliazed compared to the dxz/dyz
bands. Upon increasing temperature to above 150K, the system evolves into a
state in which the dxy bands have diminished spectral weight while the dxz/dyz
bands remain metallic. Combined with theoretical calculations, our observations
can be consistently understood as a temperature induced crossover from a
metallic state at low temperature to an orbital-selective Mott phase (OSMP) at
high temperatures. Furthermore, the fact that the superconducting state of
AFeSe is near the boundary of such an OSMP constraints the
system to have sufficiently strong on-site Coulomb interactions and Hund's
coupling, and hence highlight the non-trivial role of electron correlation in
this family of iron superconductors
Imports and Intellectual Property Rights on Innovation in China
In an open-economy R&D-based growth model with two intermediate production sectors, we find that strengthening intellectual property rights (IPR) has a positive effect on innovation in the sector that uses domestic inputs but both positive and negative effects on innovation in the sector that uses foreign inputs. We test these results using an empirical analysis of matching samples that combine Chinese provincial IPR data with industrial enterprises database and customs database
Imports and Intellectual Property Rights on Innovation in China
In an open-economy R&D-based growth model with two intermediate production sectors, we find that strengthening intellectual property rights (IPR) has a positive effect on innovation in the sector that uses domestic inputs but both positive and negative effects on innovation in the sector that uses foreign inputs. We test these results using an empirical analysis of matching samples that combine Chinese provincial IPR data with industrial enterprises database and customs database
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Functional variant of the carboxypeptidase M (CPM) gene may affect silica-related pneumoconiosis susceptibility by its expression: a multistage case-control study.
ObjectivesIn a genome-wide association study, we discovered chromosome 12q15 (defined as rs73329476) as a silica-related pneumoconiosis susceptibility region. However, the causal variants in this region have not yet been reported.MethodsWe systematically screened eight potentially functional single-neucleotide polymorphism (SNPs) in the genes near rs73329476 (carboxypeptidase M (CPM) and cleavage and polyadenylation specific factor 6 (CPSF6)) in a case-control study including 177 cases with silicosis and 204 healthy controls, matched to cases with years of silica dust exposure. We evaluated the associations between these eight SNPs and the development of silicosis. Luciferase reporter gene assays were performed to test the effects of selected SNP on the activity of CPM in the promoter. In addition, a two-stage case-control study was performed to investigate the expression differences of the two genes in peripheral blood leucocytes from a total of 64 cases with silicosis and 64 healthy controls with similar years of silica dust exposure as the cases.ResultsWe found a strong association between the mutant rs12812500 G allele and the susceptibility of silicosis (OR=1.45, 95% CI 1.03 to 2.04, p=0.034), while luciferase reporter gene assays indicated that the mutant G allele of rs12812500 is strongly associated with increased luciferase levels compared with the wild-type C allele (p<0.01). Moreover, the mRNA (peripheral blood leucocytes) expression of the CPM gene was significantly higher in subjects with silicosis compared with healthy controls.ConclusionsThe rs12812500 variant of the CPM gene may increase silicosis susceptibility by affecting the expression of CPM, which may contribute to silicosis susceptibility with biological plausibility
Job Changing Frequency and Experimental Decisions: A Field Study of Migrant Workers in the Manufacturing Industry
Migrant workers form a very important part of the labor force in the economic development of many countries. Their turnover decisions may affect the stability of the performance of manufacturing industries. It is important to understand what kind of individual behavioral preferences may affect their job changing frequency. This study conducts a lab-in-the-field experiment through a large online-to-offline job-matching platform to elicit manufacturing migrant workers’ preferences, such as uncertainty attitudes, intertemporal choices and social preferences, especially difference aversion. The study also surveyed their demographic characteristics and other factors related to their job choices. We find that subjects who are more risk seeking change jobs more frequently. We also use the job record data from the platform and conduct empirical analysis to investigate one explanation of this result: risk-seeking subjects possess more optimistic expectations of potential job opportunities and they are more likely to sample different jobs and thus generate higher job changing frequency. Our findings may help policy-makers and employers design policies or mechanisms to prevent exorbitant job-changing behavior
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