2,325 research outputs found
Recent changes of water discharge and sediment load in the Yellow River basin, China
The Yellow River basin contributes approximately 6% of the sediment load from all river systems globally, and the annual runoff directly supports 12% of the Chinese population. As a result, describing and understanding recent variations of water discharge and sediment load under global change scenarios are of considerable importance. The present study considers the annual hydrologic series of the water discharge and sediment load of the Yellow River basin obtained from 15 gauging stations (10 mainstream, 5 tributaries). The Mann-Kendall test method was adopted to detect both gradual and abrupt change of hydrological series since the 1950s. With the exception of the area draining to the Upper Tangnaihai station, results indicate that both water discharge and sediment load have decreased significantly (p<0.05). The declining trend is greater with distance downstream, and drainage area has a significant positive effect on the rate of decline. It is suggested that the abrupt change of the water discharge from the late 1980s to the early 1990s arose from human extraction, and that the abrupt change in sediment load was linked to disturbance from reservoir construction.Geography, PhysicalGeosciences, MultidisciplinarySCI(E)43ARTICLE4541-5613
Two-orbital SU(N) magnetism with ultracold alkaline-earth atoms
Fermionic alkaline-earth atoms have unique properties that make them
attractive candidates for the realization of novel atomic clocks and degenerate
quantum gases. At the same time, they are attracting considerable theoretical
attention in the context of quantum information processing. Here we demonstrate
that when such atoms are loaded in optical lattices, they can be used as
quantum simulators of unique many-body phenomena. In particular, we show that
the decoupling of the nuclear spin from the electronic angular momentum can be
used to implement many-body systems with an unprecedented degree of symmetry,
characterized by the SU(N) group with N as large as 10. Moreover, the interplay
of the nuclear spin with the electronic degree of freedom provided by a stable
optically excited state allows for the study of spin-orbital physics. Such
systems may provide valuable insights into strongly correlated physics of
transition metal oxides, heavy fermion materials, and spin liquid phases.Comment: 15 pages, 10 figures. V2: extended experimental accessibility and
Kondo sections in the main text (including new Fig. 5b) and in the Methods;
reorganized other parts; added reference
Successful treatment for acute aortic dissection in pregnancy---bentall procedure concomitant with cesarean section
Acute aortic type A dissection is a life-threatening disease that requires immediate surgical intervention. When dissection occurs during pregnancy, it is of high risk for both the mother and the fetus. In this study, we reported two cases of acute aortic dissection in late pregnancy at 28 weeks and 32 weeks of gestation respectively. After the two patients underwent a cesarean section and delivered a baby, we performed composite graft replacement of the aortic valve, aortic root and ascending aorta, with re-implantation of the coronary arteries into the graft (Bentall procedure) instead of repairing the arch with deep hypothermia and circulation arrest. Both mothers and children survived and recovered well
Endoplasmic reticulum chaperone prolyl 4-hydroxylase, beta polypeptide (P4HB) promotes malignant phenotypes in glioma via MAPK signaling
published_or_final_versio
The sudden change phenomenon of quantum discord
Even if the parameters determining a system's state are varied smoothly, the
behavior of quantum correlations alike to quantum discord, and of its classical
counterparts, can be very peculiar, with the appearance of non-analyticities in
its rate of change. Here we review this sudden change phenomenon (SCP)
discussing some important points related to it: Its uncovering,
interpretations, and experimental verifications, its use in the context of the
emergence of the pointer basis in a quantum measurement process, its appearance
and universality under Markovian and non-Markovian dynamics, its theoretical
and experimental investigation in some other physical scenarios, and the
related phenomenon of double sudden change of trace distance discord. Several
open questions are identified, and we envisage that in answering them we will
gain significant further insight about the relation between the SCP and the
symmetry-geometric aspects of the quantum state space.Comment: Lectures on General Quantum Correlations and their Applications, F.
F. Fanchini, D. O. Soares Pinto, and G. Adesso (Eds.), Springer (2017), pp
309-33
Homework self-regulation strategies: a gender and educational-level invariance analysis
This study investigates the measurement invariance as a function of gender and educational level of the Homework Behavior Questionnaire (Ktpc), an instrument developed to assess students' homework self-regulation strategies. A sample of 1400 elementary and middle school students was used. Results of confirmatory factor analysis indicated a good fit of the theoretical model composed of three dimensions: planning, execution and evaluation of the homework completion. The results also provided evidence for the existence of metric invariance and partial scalar measurement invariance across boys and girls and across the elementary school and the middle school students. The reliability of the scores in the three dimensions was high. Girls obtained higher scores than boys in planning, execution and evaluation. Middle school students had lower scores in planning compared to the elementary school students. These findings are discussed, and their implications for practice are highlighted.This study was partially conducted at the Psychology Research Centre (UID/PSI/01662/2013), University of Minho, and supported by the Portuguese Foundation for Science and Technology and the Portuguese Ministry of Science, Technology and Higher Education, through national funds, and co-financed by FEDER, through COMPETE2020, under the PT2020 Partnership Agreement (POCI-01-0145-FEDER-007653). The first author is also supported by grant SFRH/BPD/102549/2014 from the Portuguese Foundation for Science and Technology.info:eu-repo/semantics/publishedVersio
The Generation of Successive Unmarked Mutations and Chromosomal Insertion of Heterologous Genes in Actinobacillus pleuropneumoniae Using Natural Transformation
We have developed a simple method of generating scarless, unmarked mutations in Actinobacillus pleuropneumoniae by exploiting the ability of this bacterium to undergo natural transformation, and with no need to introduce plasmids encoding recombinases or resolvases. This method involves two successive rounds of natural transformation using linear DNA: the first introduces a cassette carrying cat (which allows selection by chloramphenicol) and sacB (which allows counter-selection using sucrose) flanked by sequences to either side of the target gene; the second transformation utilises the flanking sequences ligated directly to each other in order to remove the cat-sacB cassette. In order to ensure efficient uptake of the target DNA during transformation, A. pleuropneumoniae uptake sequences are added into the constructs used in both rounds of transformation. This method can be used to generate multiple successive deletions and can also be used to introduce targeted point mutations or insertions of heterologous genes into the A. pleuropneumoniae chromosome for development of live attenuated vaccine strains. So far, we have applied this method to highly transformable isolates of serovars 8 (MIDG2331), which is the most prevalent in the UK, and 15 (HS143). By screening clinical isolates of other serovars, it should be possible to identify other amenable strains
Overview on the phenomenon of two-qubit entanglement revivals in classical environments
The occurrence of revivals of quantum entanglement between separated open
quantum systems has been shown not only for dissipative non-Markovian quantum
environments but also for classical environments in absence of back-action.
While the phenomenon is well understood in the first case, the possibility to
retrieve entanglement when the composite quantum system is subject to local
classical noise has generated a debate regarding its interpretation. This
dynamical property of open quantum systems assumes an important role in quantum
information theory from both fundamental and practical perspectives. Hybrid
quantum-classical systems are in fact promising candidates to investigate the
interplay among quantum and classical features and to look for possible control
strategies of a quantum system by means of a classical device. Here we present
an overview on this topic, reporting the most recent theoretical and
experimental results about the revivals of entanglement between two qubits
locally interacting with classical environments. We also review and discuss the
interpretations provided so far to explain this phenomenon, suggesting that
they can be cast under a unified viewpoint.Comment: 16 pages, 9 figures. Chapter written for the upcoming book "Lectures
on general quantum correlations and their applications
Frozen and Invariant Quantum Discord under Local Dephasing Noise
In this chapter, we intend to explore and review some remarkable dynamical
properties of quantum discord under various different open quantum system
models. Specifically, our discussion will include several concepts connected to
the phenomena of time invariant and frozen quantum discord. Furthermore, we
will elaborate on the relation of these two phenomena to the non-Markovian
features of the open system dynamics and to the usage of dynamical decoupling
protocols.Comment: 29 pages, 8 figure
Detection of mild to moderate influenza A/H7N9 infection by China's national sentinel surveillance system for influenza-like illness: case series
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