565 research outputs found
Quasi two-dimensional antiferromagnet on a triangular lattice RbFe(MoO4)2
RbFe(MoO4)2 is a rare example of a nearly two-dimensional Heisenberg
antiferromagnet on a triangular lattice. Magnetic resonance spectra and
magnetization curves reveal that the system has a layered spin structure with
six magnetic sublattices. The sublattices within a layer are arranged in a
triangular manner with the magnetization vectors 120 degree apart. The H-T
phase diagram, containing at least five different magnetic phases is
constructed. In zero field, RbFe(MoO4)2 undergoes a phase transition at T_N=3.8
K into a non-collinear triangular spin structure with all the spins confined in
the basal plane. The application of an in-plane magnetic field induces a
collinear spin state between the fields H_c1=47 kOe and H_c2=71 kOe and
produces a magnetization plateau at one-third of the saturation moment. Both
the ESR and the magnetization measurements also clearly indicate an additional
first-order phase transition in a field of 35 kOe. The exact nature of this
phase transition is uncertain.Comment: 9 pages incl 11 figure
Forbush decrease observed by SEVAN particle detector network on November 4, 2021
On November 3-4 2021, an interplanetary coronal mass injection (ICME) hits
the magnetosphere, sparking a strong G3-class geomagnetic storm and auroras as
far south as California and New Mexico. All detectors of the SEVAN network
registered a Forbush decrease (FD) of 5-10 percentdeep in 1 minute time series
of count rates. We present the results of a comparison of Fd registered on
mountain altitudes on Aragats (Armenia), Lomnicky Stit (Slovakia), Musala
(Bulgaria), and at sea level DESY (Hamburg, Germany), and in Mileshovka,
Czechia. We present as well purity and barometric coefficients of different
coincidences of SEVAN detector layers on Aragats. We demonstrate disturbances
of the near-surface electric (NSEF) and geomagnetic fields at the arrival of
the ICME on Earth
Synthesis of structurally diverse major groove DNA interstrand crosslinks using three different aldehyde precursors
DNA interstrand crosslinks (ICLs) are extremely cytotoxic lesions that block essential cellular processes, such as replication and transcription. Crosslinking agents are widely used in cancer chemotherapy and form an array of structurally diverse ICLs. Despite the clinical success of these agents, resistance of tumors to crosslinking agents, for example, through repair of these lesions by the cellular machinery remains a problem. We have previously reported the synthesis of site-specific ICLs mimicking those formed by nitrogen mustards to facilitate the studies of cellular responses to ICL formation. Here we extend these efforts and report the synthesis of structurally diverse major groove ICLs that induce severe, little or no distortion in the DNA. Our approach employs the incorporation of aldehyde precursors of different lengths into complementary strands and ICL formation using a double reductive amination with a variety of amines. Our studies provide insight into the structure and reactivity parameters of ICL formation by double reductive amination and yield a set of diverse ICLs that will be invaluable for exploring structure-activity relationships in ICL repairope
Transition Radiation Spectroscopy with Prototypes of the ALICE TRD
We present measurements of the transition radiation (TR) spectrum produced in
an irregular radiator at different electron momenta. The data are compared to
simulations of TR from a regular radiator.Comment: 4 pages, 5 Figures, Proceedings for "TRDs for the 3rd millennium"
(Sept. 4-7, 2003, Bari, Italy
Component-Based Real-Time Operating System for Embedded Applications
Acceptance rate: 37%, Rank (CORE): AInternational audienceAs embedded systems must constantly integrate new functionalities, their developement cycles must be based on high-level abstractions, making the software design more flexible. CBSE provides an approach to these new requirements. However, low-level services provided by operating systems are an integral part of embedded applications, furthermore deployed on resource-limited devices. Therefore, the expected benefits of CBSE must not impact on the constraints imposed by the targetted domain, such as memory footprint, energy consumption, and execution time. In this paper, we present the componentization of a legacy industry-established Real-Time Operating System, and how component-based applications are built on top of it. We use the Think framework that allows to produce flexible systems while paying for flexibility only where desired. Performed experimentions show that the induced overhead is negligeable
Properties of the Volume Operator in Loop Quantum Gravity II: Detailed Presentation
The properties of the Volume operator in Loop Quantum Gravity, as constructed
by Ashtekar and Lewandowski, are analyzed for the first time at generic
vertices of valence greater than four. The present analysis benefits from the
general simplified formula for matrix elements of the Volume operator derived
in gr-qc/0405060, making it feasible to implement it on a computer as a matrix
which is then diagonalized numerically. The resulting eigenvalues serve as a
database to investigate the spectral properties of the volume operator.
Analytical results on the spectrum at 4-valent vertices are included. This is a
companion paper to arXiv:0706.0469, providing details of the analysis presented
there.Comment: Companion to arXiv:0706.0469. Version as published in CQG in 2008.
More compact presentation. Sign factor combinatorics now much better
understood in context of oriented matroids, see arXiv:1003.2348, where also
important remarks given regarding sigma configurations. Subsequent
computations revealed some minor errors, which do not change qualitative
results but modify some numbers presented her
γ-Catenin-Dependent Signals Maintain BCR-ABL1<sup>+</sup> B Cell Acute Lymphoblastic Leukemia.
The BCR-ABL1 fusion protein is the cause of chronic myeloid leukemia (CML) and of a significant fraction of adult-onset B cell acute lymphoblastic leukemia (B-ALL) cases. Using mouse models and patient-derived samples, we identified an essential role for γ-catenin in the initiation and maintenance of BCR-ABL1 <sup>+</sup> B-ALL but not CML. The selectivity was explained by a partial γ-catenin dependence of MYC expression together with the susceptibility of B-ALL, but not CML, to reduced MYC levels. MYC and γ-catenin enabled B-ALL maintenance by augmenting BIRC5 and enforced BIRC5 expression overcame γ-catenin loss. Since γ-catenin was dispensable for normal hematopoiesis, these lineage- and disease-specific features of canonical Wnt signaling identified a potential therapeutic target for the treatment of BCR-ABL1 <sup>+</sup> B-ALL
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