405 research outputs found
Impact of information sharing and buyer dependence among supply chain members on trust and strategic flexibility
Despite widespread acceptance of the idea that strategic flexibility is critical to the success of firm's operations management, strategic flexibility in supply chain management remains largely unexplored by researchers. To fill this research gap, this study attempt to propose the theoretical model of relationship among information sharing, the buyer's dependence, trust and strategic flexibility in a supply chain. Based on the sample of 145 manufacturing firms in Yangtze River Delta, the empirical test of related hypothesis is examined by multiple regression analysis. The results reveal that information sharing between suppliers and buyers improves their trust. In addition, considering the relationship between buyer dependence and trust, there are significant and negative effects of buyer dependence and its 'influence' dimension on trust. Finally, this study finds that alternatives and influence has significantly negative impact on strategic flexibility while trust and information sharing has significantly positive impact on strategic flexibility. Consequently, information sharing has a direct and indirect influence on strategic flexibility. These findings suggest the firm should pay emphasis on the evaluation of information sharing and supplier influence and enhance trust relationship between suppliers and buyers
Enabling Runtime Verification of Causal Discovery Algorithms with Automated Conditional Independence Reasoning (Extended Version)
Causal discovery is a powerful technique for identifying causal relationships
among variables in data. It has been widely used in various applications in
software engineering. Causal discovery extensively involves conditional
independence (CI) tests. Hence, its output quality highly depends on the
performance of CI tests, which can often be unreliable in practice. Moreover,
privacy concerns arise when excessive CI tests are performed.
Despite the distinct nature between unreliable and excessive CI tests, this
paper identifies a unified and principled approach to addressing both of them.
Generally, CI statements, the outputs of CI tests, adhere to Pearl's axioms,
which are a set of well-established integrity constraints on conditional
independence. Hence, we can either detect erroneous CI statements if they
violate Pearl's axioms or prune excessive CI statements if they are logically
entailed by Pearl's axioms. Holistically, both problems boil down to reasoning
about the consistency of CI statements under Pearl's axioms (referred to as CIR
problem).
We propose a runtime verification tool called CICheck, designed to harden
causal discovery algorithms from reliability and privacy perspectives. CICheck
employs a sound and decidable encoding scheme that translates CIR into SMT
problems. To solve the CIR problem efficiently, CICheck introduces a four-stage
decision procedure with three lightweight optimizations that actively prove or
refute consistency, and only resort to costly SMT-based reasoning when
necessary. Based on the decision procedure to CIR, CICheck includes two
variants: ED-CICheck and ED-CICheck, which detect erroneous CI tests (to
enhance reliability) and prune excessive CI tests (to enhance privacy),
respectively. [abridged due to length limit
(E)-5-(3,5-Dimethylphenyl)-N-[4-(methylsulfanyl)benzylidene]-1,3,4-thiadiazol-2-amine
The title compound, C18H17N3S2, was synthesized by the reaction of 5-(3,5-dimethylphenyl)-1,3,4-thiadiazol-2-amine and 4-(methylsulfanyl)benzaldehyde. An intramolecular C—H⋯S hydrogen bond results in the formation of a planar (r.m.s. deviation = 0.003 Å) five-membered ring. In the crystal structure, intermolecular C—H⋯N hydrogen bonds link the molecules to form layers parallel to (011)
6,10,16,19-Tetraoxatrispiro[4.2.2.4.2.2]nonadecane
The asymmetric unit of the title compound, C15H24O4, contains one half-molecule; a twofold rotation axis passes through the central C atom. The non-planar six- and five-membered rings adopt chair and envelope conformations, respectively. In the crystal structure, intermolecular C—H⋯O hydrogen bonds link the molecules
(S)-Ethyl 2-[4-(6-chloroquinoxalin-2-yloxy)phenoxy]propanoate
In the molecule of the title compound, C19H17ClN2O4, the quinoxaline ring system is planar [maximum deviation = 0.013 (3) Å] and oriented at a dihedral angle of 80.18 (3)° with respect to the benzene ring. In the crystal structure, intermolecular C—H⋯N interactions link molecules into chains. π–π contacts between the quinoxaline systems [centroid–centroid distance = 3.654 (1) Å] may further stabilize the structure
Low compressible noble metal carbides with rock-salt structure: ab initio total energy calculations of the elastic stability
We have systematically studied the mechanical stability of all noble metal
carbides with the rock-salt structure by calculating their elastic constants
within the density function theory scheme. It was found that only four carbides
(RuC, PdC, AgC and PtC) are mechanically stable. In particular, we have shown
that RuC, PdC, and PtC have very high bulk modulus, which has been remarkably
observed by the most recent experiment for the case of PtC. From the calculated
density of states, we can conclude that these compounds are metallic, like the
conventional group IV and group V transition metal carbides.Comment: Appl. Phys. Lett. 89, 071913 (2006
Quantum Griffiths singularity in three-dimensional superconductor to Anderson critical insulator transition
Disorder is ubiquitous in real materials and can have dramatic effects on
quantum phase transitions. Originating from the disorder enhanced quantum
fluctuation, quantum Griffiths singularity (QGS) has been revealed as a
universal phenomenon in quantum criticality of low-dimensional superconductors.
However, due to the weak fluctuation effect, QGS is very challenging to detect
experimentally in three-dimensional (3D) superconducting systems. Here we
report the discovery of QGS associated with the quantum phase transition from
3D superconductor to Anderson critical insulator in a spinel oxide MgTi2O4
(MTO). Under both perpendicular and parallel magnetic field, the dynamical
critical exponent diverges when approaching the quantum critical point,
demonstrating the existence of 3D QGS. Among 3D superconductors, MTO shows
relatively strong fluctuation effect featured as a wide superconducting
transition region. The enhanced fluctuation, which may arise from the mobility
edge of Anderson localization, finally leads to the occurrence of 3D quantum
phase transition and QGS. Our findings offer a new perspective to understand
quantum phase transitions in strongly disordered 3D systems
RNA-binding protein CUGBP1 regulates insulin secretion via activation of phosphodiesterase 3B in mice
International audienceAims/hypothesis: CUG-binding protein 1 (CUGBP1) is a multifunctional RNA-binding protein that regulates RNA processing at several stages including translation, deadenylation and alternative splicing, as well as RNA stability. Recent studies indicate that CUGBP1 may play a role in metabolic disorders. Our objective was to examine its role in endocrine pancreas function through gain- and loss-of-function experiments and to further decipher the underlying molecular mechanisms.Methods: A mouse model in which type 2 diabetes was induced by a high-fat diet (HFD; 60% energy from fat) and mice on a standard chow diet (10% energy from fat) were compared. Pancreas-specific CUGBP1 overexpression and knockdown mice were generated. Different lengths of the phosphodiesterase subtype 3B (PDE3B) 3′ untranslated region (UTR) were cloned for luciferase reporter analysis. Purified CUGBP1 protein was used for gel shift experiments.Results: CUGBP1 is present in rodent islets and in beta cell lines; it is overexpressed in the islets of diabetic mice. Compared with control mice, the plasma insulin level after a glucose load was significantly lower and glucose clearance was greatly delayed in mice with pancreas-specific CUGBP1 overexpression; the opposite results were obtained upon pancreas-specific CUGBP1 knockdown. Glucose- and glucagon-like peptide1 (GLP-1)-stimulated insulin secretion was significantly attenuated in mouse islets upon CUGBP1 overexpression. This was associated with a strong decrease in intracellular cAMP levels, pointing to a potential role for cAMP PDEs. CUGBP1 overexpression had no effect on the mRNA levels of PDE1A, 1C, 2A, 3A, 4A, 4B, 4D, 7A and 8B subtypes, but resulted in increased PDE3B expression. CUGBP1 was found to directly bind to a specific ATTTGTT sequence residing in the 3′ UTR of PDE3B and stabilised PDE3B mRNA. In the presence of the PDE3 inhibitor cilostamide, glucose- and GLP-1-stimulated insulin secretion was no longer reduced by CUGBP1 overexpression. Similar to CUGBP1, PDE3B was overexpressed in the islets of diabetic mice.Conclusions/interpretation: We conclude that CUGBP1 is a critical regulator of insulin secretion via activating PDE3B. Repressing this protein might provide a potential strategy for treating type 2 diabetes
Potential super-hard Osmium di-nitride with fluorite structure: First-principles calculations
We have performed systematic first-principles calculations on di-carbide,
-nitride, -oxide and -boride of platinum and osmium with the fluorite
structure. It is found that only PtN, OsN and OsO are
mechanically stable. In particular OsN has the highest bulk modulus of
360.7 GPa. Both the band structure and density of states show that the new
phase of OsN is metallic. The high bulk modulus is owing to the strong
covalent bonding between Os 5\textit{d} and N 2\textit{p} states and the dense
packed fluorite structure.Comment: Phys. Rev. B 74,125118 (2006
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