In many plant species, flowering is promoted by the cold treatment or vernalization. The mechanism of vernalization-induced flowering has been extensively studied in
but remains largely unknown in ...legumes. The orthologs of the
gene, a major regulator of vernalization response in
, are absent or non-functional in the vernalization-sensitive legume species. Nevertheless, the legume integrator genes
and
are involved in the transition of the vernalization signal to meristem identity genes, including
(
ortholog). However, the regulatory contribution of these genes to
activation in legumes remains elusive. Here, we presented the theoretical and data-driven analyses of a feed-forward regulatory motif that includes a vernalization-responsive
gene and several
genes, which independently activate
and thereby mediate floral transition. Our theoretical model showed that the multiple regulatory branches in this regulatory motif facilitated the elimination of no-sense signals and amplified useful signals from the upstream regulator. We further developed and analyzed four data-driven models of
activation in
in vernalized and non-vernalized conditions in wild-type and
mutants. The model with
providing both direct activation and indirect activation via three intermediate activators,
,
, and
, resulted in the most relevant
dynamics. In this model, the difference between regulatory inputs of
genes was nonessential. As a result, in the
model, the cumulative action of
,
, and
was favored. Overall, in this study, we first presented the in silico analysis of vernalization-induced flowering in legumes. The considered vernalization network motif can be supplemented with additional regulatory branches as new experimental data become available.
Unlike transcriptional regulation, the post-transcriptional mechanisms underlying zygotic segmentation gene expression in early Drosophila embryo have been insufficiently investigated. ...Condition-specific post-transcriptional regulation plays an important role in the development of many organisms. Our recent study revealed the domain- and genotype-specific differences between mRNA and the protein expression of Drosophila hb, gt, and eve genes in cleavage cycle 14A. Here, we use this dataset and the dynamic mathematical model to recapitulate protein expression from the corresponding mRNA patterns. The condition-specific nonuniformity in parameter values is further interpreted in terms of possible post-transcriptional modifications. For hb expression in wild-type embryos, our results predict the position-specific differences in protein production. The protein synthesis rate parameter is significantly higher in hb anterior domain compared to the posterior domain. The parameter sets describing Gt protein dynamics in wild-type embryos and Kr mutants are genotype-specific. The spatial discrepancy between gt mRNA and protein posterior expression in Kr mutants is well reproduced by the whole axis model, thus rejecting the involvement of post-transcriptional mechanisms. Our models fail to describe the full dynamics of eve expression, presumably due to its complex shape and the variable time delays between mRNA and protein patterns, which likely require a more complex model. Overall, our modeling approach enables the prediction of regulatory scenarios underlying the condition-specific differences between mRNA and protein expression in early embryo.
Study of K+→π0e+νγ decay with OKA setup Polyarush, A. Yu; Akimenko, S. A.; Artamonov, A. V. ...
The European physical journal. C, Particles and fields,
02/2021, Volume:
81, Issue:
2
Journal Article
Peer reviewed
Open access
Results of a study of the
K
+
→
π
0
e
+
ν
γ
decay at OKA setup are presented. More than 32,000 events of this decay are observed. The differential spectra over the photon energy and the ...photon–electron opening angle in kaon rest frame are presented. The branching ratios, normalized to that of
K
e
3
decay are calculated for different cuts on
E
γ
∗
and
c
o
s
Θ
e
γ
∗
. In particular, the branching ratio for
E
γ
∗
>
30
MeV and
Θ
e
γ
∗
>
20
∘
is measured R =
B
r
(
K
+
→
π
0
e
+
ν
e
γ
)
B
r
(
K
+
→
π
0
e
+
ν
e
)
= = (0.587±0.010(
stat
.)±0.015(
syst
.))
×
10
-
2
, which is in a good agreement with ChPT
O
(
p
4
)
calculations.
Results of a numerical study of performance characteristics of supersonic ejectors with nozzles of different types are reported. The work was carried out with the aim of developing a high-performance ...ejector for pressure recovery systems of supersonic chemical lasers. A specific feature of the operation of ejectors in pressure recovery systems consists in that, in this case, the ejecting and ejected gases, as they undergo mixing, have different thermodynamic properties, and the ejection coefficient depends on the ratio between the temperatures of the gases and on the ratio of their molecular masses. Since the operation of an ejector is based on the mixing process, the task consisted in intensification of this process using nozzles of special geometries. The performance of ejectors was judged considering an integral parameter, the product of induction by compression ratio. The calculations of the 3D viscous gas flow in the ejector channel were performed using ANSYS software. In verifying the numerical model, a comparison with experimental data obtained earlier on a model ejector facility and during tests of real pressure recovery systems in operation with supersonic chemical lasers was performed.
The
T
-odd correlation
, which is the mixed product of the momenta of
,
, and γ in the system of rest of the kaon divided by
, has been measured in the
K
+
→ π
0
e
+
ν
e
γ radiative decay among 101 ...200 candidate events detected at the OKA setup. The asymmetry of the distribution in
is characterized by the ratio
, where
is the number of events with positive (negative) ξ. The value
= (+0.1 ± 3.9(stat.) ± 1.7(syst.)) × 10
–3
or
(90% C.L.) has been obtained.
On the statistics of ~1.7 × 10
8
interactions of positively charged kaons on copper nuclei, coherent events of the
K
+
π
0
system production are selected. The cross sections for the Coulomb and ...coherent strong components and their interference in the region of the
K
*(892) meson are measured. The partial width for the decay
K
*(892) →
K
+
γ is determined. When studying the mass spectrum of the
K
+
π
0
system, an effect which can be interpreted as the interference of the chiral anomaly and the
K
*(892)
s
-channel amplitudes is found. This gives an estimate for the ratio of the observed amplitude of the chiral anomaly to the theoretical one:
A
exp
/
A
th
= 0.9 ± 0.24(stat.) ± 0.3(syst.).
Abstract Results of a study of the $$K^+ \rightarrow \pi ^{0} e^{+} \nu \gamma $$ K + → π 0 e + ν γ decay at OKA setup are presented. More than 32,000 events of this decay are observed. The ...differential spectra over the photon energy and the photon–electron opening angle in kaon rest frame are presented. The branching ratios, normalized to that of $$K_{e3}$$ K e 3 decay are calculated for different cuts on $$E^*_\gamma $$ E γ ∗ and $$cos\Theta ^{*}_{e\gamma }$$ c o s Θ e γ ∗ . In particular, the branching ratio for $$E^{*}_{\gamma }>30$$ E γ ∗ > 30 MeV and $$\Theta ^{*}_{e \gamma }>20^{\circ }$$ Θ e γ ∗ > 20 ∘ is measured R = $$\frac{Br(K^+ \rightarrow \pi ^{0} e^{+} \nu _{e} \gamma ) }{Br(K^+ \rightarrow \pi ^{0} e^{+} \nu _{e})} $$ B r ( K + → π 0 e + ν e γ ) B r ( K + → π 0 e + ν e ) = = (0.587±0.010(stat.)±0.015(syst.)) $$\times 10^{-2}$$ × 10 - 2 , which is in a good agreement with ChPT $$O(p^{4})$$ O ( p 4 ) calculations.
The greatest placer potential in northwest Canada lies in preglacial drainage systems. The largest placer gold deposits are associated with Pliocene pre-glacial fluvial gravels of the Dawson Range ...(in particular Klondike Plateau) of west-central Yukon. The abundance and/or the lack of gold concentration in this area were controlled by the ability of the streams to aggrade in response to changes caused by extensional faulting in the Tintina Trench, differential uplift, and regional denudation. Gold bearing gravels in the northern and eastern slopes of the Dawson Range are found in low order tributaries of the pre-glacial south-flowing Yukon River. Glaciation played an important role in masking and changing the direction of drainage, and creating new channels in this region. The earliest known drainage changes relate to Late Miocene formation of the Tintina Trench, and Early Pliocene uplift of the St. Elias Mountains. Prior to these events the Yukon River drained south into the Gulf of Alaska. Initial regional glaciation (2.6–2.9
Ma) diverted the southward drainage toward the northwest, becoming part of the Kwikhpak River in Alaska. The present Yukon River drainage basin is about 27.5% larger than the ancestral Kwikhpak River basin. The evolution of the river is described here in three stages (1) drainage in pre-Late Miocene, (2) drainage in Early Pliocene and (3) drainage after earliest Pliocene glaciation.
Abstract A precise measurement of the vector and axial-vector form factors difference $$F_V-F_A$$ FV-FA in the $$K^+\rightarrow {\mu ^+}{\nu _{\mu }}{\gamma }$$ K+→μ+νμγ decay is presented. About 95K ...events of $$K^+\rightarrow {\mu ^+}{\nu _{\mu }}{\gamma }$$ K+→μ+νμγ are selected in the OKA experiment. The result is $$F_V-F_A=0.134\pm 0.021(stat)\pm 0.027(syst)$$ FV-FA=0.134±0.021(stat)±0.027(syst) . Both errors are smaller than in the previous $$F_V-F_A$$ FV-FA measurements.
In many plant species, flowering is promoted by the cold treatment or vernalization. The mechanism of vernalization-induced flowering has been extensively studied in Arabidopsis but remains largely ...unknown in legumes. The orthologs of the FLC gene, a major regulator of vernalization response in Arabidopsis, are absent or non-functional in the vernalization-sensitive legume species. Nevertheless, the legume integrator genes FT and SOC1 are involved in the transition of the vernalization signal to meristem identity genes, including PIM (AP1 ortholog). However, the regulatory contribution of these genes to PIM activation in legumes remains elusive. Here, we presented the theoretical and data-driven analyses of a feed-forward regulatory motif that includes a vernalization-responsive FT gene and several SOC1 genes, which independently activate PIM and thereby mediate floral transition. Our theoretical model showed that the multiple regulatory branches in this regulatory motif facilitated the elimination of no-sense signals and amplified useful signals from the upstream regulator. We further developed and analyzed four data-driven models of PIM activation in Medicago trancatula in vernalized and non-vernalized conditions in wild-type and fta1-1 mutants. The model with FTa1 providing both direct activation and indirect activation via three intermediate activators, SOC1a, SOC1b, and SOC1c, resulted in the most relevant PIM dynamics. In this model, the difference between regulatory inputs of SOC1 genes was nonessential. As a result, in the M. trancatula model, the cumulative action of SOC1a, SOC1b, and SOC1c was favored. Overall, in this study, we first presented the in silico analysis of vernalization-induced flowering in legumes. The considered vernalization network motif can be supplemented with additional regulatory branches as new experimental data become available.
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