105 research outputs found
Functional upgrading in China’s export processing sector
Functional upgrading occurs when a firm acquires more sophisticated functions within an existing value chain. In this paper, we analyze if there is evidence of this type of upgrading in China’s export processing regime by investigating dynamics in the relative prevalence of Import & Assembly (IA) versus Pure Assembly (PA) processing trade over the period 2000-2013. Firms in both regimes provide similar manufacturing services to foreign companies, but IA firms also conduct the sophisticated tasks of quality control, searching, financing and storing imported materials. Consistent with a trend of functional upgrading, we show that the share of IA trade in total processing trade has increased rapidly during the period 2000-2006, both overall and within product categories. Furthermore, we find that this trend has gone hand in hand with improvements in a sector’s labor productivity and unit values. Against expectations, we find that this process has slowed down notably during the period 2006-2013.status: publishe
Temperature chaos is present in off-equilibrium spin-glass dynamics
Experiments featuring non-equilibrium glassy dynamics under temperature changes still await interpretation. There is a widespread feeling that temperature chaos (an extreme sensitivity of the glass to temperature changes) should play a major role but, up to now, this phenomenon has been investigated solely under equilibrium conditions. In fact, the very existence of a chaotic effect in the non-equilibrium dynamics is yet to be established. In this article, we tackle this problem through a large simulation of the 3D Edwards-Anderson model, carried out on the Janus II supercomputer. We find a dynamic effect that closely parallels equilibrium temperature chaos. This dynamic temperature-chaos effect is spatially heterogeneous to a large degree and turns out to be controlled by the spin-glass coherence length ¿. Indeed, an emerging length-scale ¿* rules the crossover from weak (at ¿ « ¿*) to strong chaos (¿ » ¿*). Extrapolations of ¿* to relevant experimental conditions are provided. © 2021, The Author(s)
Temperature chaos is present in off-equilibrium spin-glass dynamics
We find a dynamic effect in the non-equilibrium dynamics of a spin glass that
closely parallels equilibrium temperature chaos. This effect, that we name
dynamic temperature chaos, is spatially heterogeneous to a large degree. The
key controlling quantity is the time-growing spin-glass coherence length. Our
detailed characterization of dynamic temperature chaos paves the way for the
analysis of recent and forthcoming experiments. This work has been made
possible thanks to the most massive simulation to date of non-equilibrium
dynamics, carried out on the Janus~II custom-built supercomputer.Comment: Version accepted for publication in Communication Physics 10 pages, 9
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Scaling law describes the spin-glass response in theory, experiments and simulations
The correlation length , a key quantity in glassy dynamics, can now be
precisely measured for spin glasses both in experiments and in simulations.
However, known analysis methods lead to discrepancies either for large external
fields or close to the glass temperature. We solve this problem by introducing
a scaling law that takes into account both the magnetic field and the
time-dependent spin-glass correlation length. The scaling law is successfully
tested against experimental measurements in a CuMn single crystal and against
large-scale simulations on the Janus II dedicated computer.Comment: Revised version, including supplemental materia
Spin-glass dynamics in the presence of a magnetic field: exploration of microscopic properties
The synergy between experiment, theory, and simulations enables a microscopic
analysis of spin-glass dynamics in a magnetic field in the vicinity of and
below the spin-glass transition temperature . The spin-glass
correlation length, , is analysed both in experiments
and in simulations in terms of the waiting time after the spin
glass has been cooled down to a stabilised measuring temperature
and of the time after the magnetic field is changed. This
correlation length is extracted experimentally for a CuMn 6 at. % single
crystal, as well as for simulations on the Janus II special-purpose
supercomputer, the latter with time and length scales comparable to experiment.
The non-linear magnetic susceptibility is reported from experiment and
simulations, using as the scaling variable. Previous
experiments are reanalysed, and disagreements about the nature of the Zeeman
energy are resolved. The growth of the spin-glass magnetisation in zero-field
magnetisation experiments, , is measured from
simulations, verifying the scaling relationships in the dynamical or
non-equilibrium regime. Our preliminary search for the de Almeida-Thouless line
in is discussed.Comment: 49 pages, figures 2
De novo domestication of wild tomato using genome editing
Breeding of crops over millennia for yield and productivity1 has led to reduced genetic diversity. As a result, beneficial traits of wild species, such as disease resistance and stress tolerance, have been lost2. We devised a CRISPR–Cas9 genome engineering strategy to combine agronomically desirable traits with useful traits present in wild lines. We report that editing of six loci that are important for yield and productivity in present-day tomato crop lines enabled de novo domestication of wild Solanum pimpinellifolium. Engineered S. pimpinellifolium morphology was altered, together with the size, number and nutritional value of the fruits. Compared with the wild parent, our engineered lines have a threefold increase in fruit size and a tenfold increase in fruit number. Notably, fruit lycopene accumulation is improved by 500% compared with the widely cultivated S. lycopersicum. Our results pave the way for molecular breeding programs to exploit the genetic diversity present in wild plants
Association of TLR7 Variants with AIDS-Like Disease and AIDS Vaccine Efficacy in Rhesus Macaques
In HIV infection, TLR7-triggered IFN-α production exerts a direct antiviral effect through the inhibition of viral replication, but may also be involved in immune pathogenesis leading to AIDS. TLR7 could also be an important mediator of vaccine efficacy. In this study, we analyzed polymorphisms in the X-linked TLR7 gene in the rhesus macaque model of AIDS. Upon resequencing of the TLR7 gene in 36 rhesus macaques of Indian origin, 12 polymorphic sites were detected. Next, we identified three tightly linked single nucleotide polymorphisms (SNP) as being associated with survival time. Genotyping of 119 untreated, simian immunodeficiency virus (SIV)-infected male rhesus macaques, including an ‘MHC adjusted’ subset, revealed that the three TLR7 SNPs are also significantly associated with set-point viral load. Surprisingly, this effect was not observed in 72 immunized SIV-infected male monkeys. We hypothesize (i) that SNP c.13G>A in the leader peptide is causative for the observed genotype-phenotype association and that (ii) the underlying mechanism is related to RNA secondary structure formation. Therefore, we investigated a fourth SNP (c.-17C>T), located 17 bp upstream of the ATG translation initiation codon, that is also potentially capable of influencing RNA structure. In c.13A carriers, neither set-point viral load nor survival time were related to the c.-17C>T genotype. In c.13G carriers, by contrast, the c.-17C allele was significantly associated with prolonged survival. Again, no such association was detected among immunized SIV-infected macaques. Our results highlight the dual role of TLR7 in immunodeficiency virus infection and vaccination and imply that it may be important to control human AIDS vaccine trials, not only for MHC genotype, but also for TLR7 genotype
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