368 research outputs found
Remote ID for separation provision and multi-agent navigation
In this paper, we investigate the integration of drone identification data
(Remote ID) with collision avoidance mechanisms to improve the safety and
efficiency of multi-drone operations. We introduce an improved Near Mid-Air
Collision (NMAC) definition, termed as UAV NMAC (uNMAC), which accounts for
uncertainties in the drone's location due to self-localization errors and
possible displacements between two location reports. Our proposed uNMAC-based
Reciprocal Velocity Obstacle (RVO) model integrates Remote ID messages with RVO
to enable enhanced collision-free navigation. We propose modifications to the
Remote ID format to include data on localization accuracy and drone airframe
size, facilitating more efficient collision avoidance decisions. Through
extensive simulations, we demonstrate that our approach halves mission
execution times compared to a conservative standard Remote ID-based RVO.
Importantly, it ensures collision-free operations even under localization
uncertainties. By integrating the improved Remote ID messages and uNMAC-based
RVO, we offer a solution to significantly increase airspace capacity while
adhering to strict safety standards. Our study emphasizes the potential to
augment the safety and efficiency of future drone operations, thereby
benefiting industries reliant on drone technologies.Comment: 10 pages, 8 figures, 2023 IEEE/AIAA 42nd Digital Avionics Systems
Conference (DASC
Distinct HDACs regulate the transcriptional response of human cyclin-dependent kinase inhibitor genes to trichostatin A and 1α,25-dihydroxyvitamin D3
The anti-proliferative effects of histone deacetylase (HDAC) inhibitors and 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3] converge via the interaction of un-liganded vitamin D receptor (VDR) with co-repressors recruiting multiprotein complexes containing HDACs and via the induction of cyclin-dependent kinase inhibitor (CDKI) genes of the INK4 and Cip/Kip family. We investigated the effects of the HDAC inhibitor Trichostatin A (TSA) and 1α,25(OH)2D3 on the proliferation and CDKI gene expression in malignant and non-malignant mammary epithelial cell lines. TSA induced the INK4-family genes p18 and p19, whereas the Cip/Kip family gene p21 was stimulated by 1α,25(OH)2D3. Chromatin immunoprecipitation and RNA inhibition assays showed that the co-repressor NCoR1 and some HDAC family members complexed un-liganded VDR and repressed the basal level of CDKI genes, but their role in regulating CDKI gene expression by TSA and 1α,25(OH)2D3 were contrary. HDAC3 and HDAC7 attenuated 1α,25(OH)2D3-dependent induction of the p21 gene, for which NCoR1 is essential. In contrast, TSA-mediated induction of the p18 gene was dependent on HDAC3 and HDAC4, but was opposed by NCoR1 and un-liganded VDR. This suggests that the attenuation of the response to TSA by NCoR1 or that to 1α,25(OH)2D3 by HDACs can be overcome by their combined application achieving maximal induction of anti-proliferative target genes
Synergistic Interactions between HDAC and Sirtuin Inhibitors in Human Leukemia Cells
Aberrant histone deacetylase (HDAC) activity is frequent in human leukemias. However, while classical, NAD+-independent HDACs are an established therapeutic target, the relevance of NAD+-dependent HDACs (sirtuins) in leukemia treatment remains unclear. Here, we assessed the antileukemic activity of sirtuin inhibitors and of the NAD+-lowering drug FK866, alone and in combination with traditional HDAC inhibitors. Primary leukemia cells, leukemia cell lines, healthy leukocytes and hematopoietic progenitors were treated with sirtuin inhibitors (sirtinol, cambinol, EX527) and with FK866, with or without addition of the HDAC inhibitors valproic acid, sodium butyrate, and vorinostat. Cell death was quantified by propidium iodide cell staining and subsequent flow-cytometry. Apoptosis induction was monitored by cell staining with FITC-Annexin-V/propidium iodide or with TMRE followed by flow-cytometric analysis, and by measuring caspase3/7 activity. Intracellular Bax was detected by flow-cytometry and western blotting. Cellular NAD+ levels were measured by enzymatic cycling assays. Bax was overexpressed by retroviral transduction. Bax and SIRT1 were silenced by RNA-interference. Sirtuin inhibitors and FK866 synergistically enhanced HDAC inhibitor activity in leukemia cells, but not in healthy leukocytes and hematopoietic progenitors. In leukemia cells, HDAC inhibitors were found to induce upregulation of Bax, a pro-apoptotic Bcl2 family-member whose translocation to mitochondria is normally prevented by SIRT1. As a result, leukemia cells become sensitized to sirtuin inhibitor-induced apoptosis. In conclusion, NAD+-independent HDACs and sirtuins cooperate in leukemia cells to avoid apoptosis. Combining sirtuin with HDAC inhibitors results in synergistic antileukemic activity that could be therapeutically exploited
Precision measurement of violation in the penguin-mediated decay
A flavor-tagged time-dependent angular analysis of the decay
is performed using collision data collected
by the LHCb experiment at % at TeV, the center-of-mass energy of
13 TeV, corresponding to an integrated luminosity of 6 fb^{-1}. The
-violating phase and direct -violation parameter are measured
to be rad and
, respectively, assuming the same values
for all polarization states of the system. In these results, the
first uncertainties are statistical and the second systematic. These parameters
are also determined separately for each polarization state, showing no evidence
for polarization dependence. The results are combined with previous LHCb
measurements using collisions at center-of-mass energies of 7 and 8 TeV,
yielding rad and . This is the most precise study of time-dependent violation
in a penguin-dominated meson decay. The results are consistent with
symmetry and with the Standard Model predictions.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-001.html (LHCb
public pages
Study of charmonium decays to in the channels
A study of the and decays
is performed using proton-proton collisions at center-of-mass energies of 7, 8
and 13 TeV at the LHCb experiment. The invariant mass spectra from
both decay modes reveal a rich content of charmonium resonances. New precise
measurements of the and resonance parameters are
performed and branching fraction measurements are obtained for decays to
, , and resonances. In particular, the
first observation and branching fraction measurement of is reported as well as first measurements of the
and branching fractions. Dalitz plot analyses of
and decays are performed. A
new measurement of the amplitude and phase of the -wave as functions
of the mass is performed, together with measurements of the
, and parameters. Finally, the branching
fractions of decays to resonances are also measured.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-051.html (LHCb
public pages
Measurement of the differential branching fraction
The branching fraction of the rare decay is measured for the first time, in the squared dimuon mass
intervals, , excluding the and regions. The data
sample analyzed was collected by the LHCb experiment at center-of-mass energies
of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of $9\
\mathrm{fb}^{-1}q^{2}q^{2} >15.0\
\mathrm{GeV}^2/c^4$, where theoretical predictions have the smallest model
dependence, agrees with the predictions.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-050.html (LHCb
public pages
Measurement of the mass difference and relative production rate of the and baryons
The mass difference between the and baryons is
measured using proton-proton collision data collected by the LHCb experiment,
corresponding to an integrated luminosity of , and is
found to be \begin{equation} m(\Omega^-_b)- m(\Xi^-_b) = 248.54 \pm 0.51
\text{(stat)} \pm 0.38 \text{(syst)} \, \text{MeV}/c^2. \end{equation} The mass
of the baryon is measured to be \begin{equation} m(\Omega^-_b)=
6045.9 \pm 0.5 \text{(stat)} \pm 0.6 \text{(syst)} \, \text{MeV}/c^2.
\end{equation} This is the most precise determination of the mass
to date. In addition, the production rate of baryons relative to
that of baryons is measured for the first time in collisions,
using an LHCb dataset collected at a center-of-mass energy of and corresponding to an integrated luminosity of
. Reconstructing beauty baryons in the kinematic region and with their decays to a meson
and a hyperon, the ratio \begin{equation}
\frac{f_{\Omega^-_b}}{f_{\Xi^-_b}}\times\frac{\mathcal{B}(\Omega^-_b \to J/\psi
\Omega^-)}{\mathcal{B}(\Xi^-_b \to J/\psi \Xi^-)} = 0.120 \pm 0.008
\text{(stat)} \pm 0.008 \text{(syst)}, \end{equation} is obtained, where
and are the fragmentation fractions of
quarks into and baryons, respectively, and
represents the branching fractions of their respective decays.Comment: 23 pages, 3 figures. All figures and tables, along with any
supplementary material and additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-053.html (LHCb
public pages
Measurement of the CKM angle in the channel using self-conjugate decays
A model-independent study of CP violation in decays is
presented using data corresponding to an integrated luminosity of 9fb
collected by the LHCb experiment at centre-of-mass energies of and TeV. The CKM angle is determined by examining the
distributions of signal decays in phase-space bins of the self-conjugate decays, where .
Observables related to CP violation are measured and the angle is
determined to be . Measurements of the
amplitude ratio and strong-phase difference between the favoured and suppressed
decays are also presented.Comment: All figures and tables, along with machine-readable versions and any
supplementary material and additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-009.html (LHCb
public pages
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