5,234 research outputs found
Mellin–Barnes integrals as Fourier–Mukai transforms
No full textAbstractWe study the generalized hypergeometric system introduced by Gelfand, Kapranov and Zelevinsky and its relationship with the toric Deligne–Mumford (DM) stacks recently studied by Borisov, Chen and Smith. We construct series solutions with values in a combinatorial version of the Chen–Ruan (orbifold) cohomology and in the K-theory of the associated DM stacks. In the spirit of the homological mirror symmetry conjecture of Kontsevich, we show that the K-theory action of the Fourier–Mukai functors associated to basic toric birational maps of DM stacks are mirrored by analytic continuation transformations of Mellin–Barnes type
Increased leukotriene B4 and interleukin-6 in exhaled breath condensate in cystic fibrosis.
No full textDistinct Intracellular Compartments Involved in Invariant Chain Degradation and Antigenic Peptide Loading of Major Histocompatibility Complex (MHC) Class II Molecules
No full textMajor histocompatibility complex (MHC) class II molecules are transported to intracellular MHC class II compartments via a transient association with the invariant chain (Ii). After removal of the invariant chain, peptides can be loaded onto class II molecules, a process catalyzed by human leukocyte antigen-DM (HLA-DM) molecules. Here we show that MHC class II compartments consist of two physically and functionally distinct organelles. Newly synthesized MHC class II/Ii complexes were targeted to endocytic organelles lacking HLA-DM molecules, where Ii degradation occurred. From these organelles, class II molecules were transported to a distinct organelle containing HLADM, in which peptides were loaded onto class II molecules. This latter organelle was not directly accessible via fluid phase endocytosis, suggesting that it is not part of the endosomal pathway. Uptake via antigen-specific membrane immunoglobulin resulted however in small amounts of antigen in the HLA-DM positive organelles. From this peptide-loading compartment, class II–peptide complexes were transported to the plasma membrane, in part after transit through endocytic organelles. The existence of two separate compartments, one involved in Ii removal and the other functioning in HLA-DM–dependent peptide loading of class II molecules, may contribute to the efficiency of antigen presentation by the selective recruitment of peptide-receptive MHC class II molecules and HLA-DM to the same subcellular location
Apoptosis, ageing and cancer susceptibility
No full textWe have previously shown that peripheral blood lymphocytes (PBL) from individuals carrying a germline TP53 mutation show a dramatically reduced apoptotic response to radiation. As part of a study of this phenomenon, we also investigated apoptotic response in a series of breast cancer patients lacking TP53 mutations and in a control group of individuals without cancer. There was a significant reduction in mean apoptotic response with increasing age in all groups. These findings are consistent with a number of studies in rodents, which have demonstrated a reduction in DNA damage-induced apoptosis with increasing age. In addition, after adjusting for age, breast cancer patients showed significantly reduced apoptotic responses compared with normal controls (P=0.002). The odds ratio for breast cancer in women with an apoptotic response of <35%, compared with women with a response of >49%, was 6.42 (95% CI 1.68-24.6). The data further support the hypothesis that a reduction in apoptotic response to DNA damage with increasing age may play a significant role in the age-related increase in cancer
Haptic communication for remote mobile and manipulator robot operations in hazardous environments
No full textNuclear decommissioning involves the use of remotely deployed mobile vehiclesand manipulators controlled via teleoperation systems. Manipulators are used fortooling and sorting tasks, and mobile vehicles are used to locate a manipulatornear to the area that it is to be operated upon and also to carry a camera into aremote area for monitoring and assessment purposes.Teleoperations in hazardous environments are often hampered by a lack of visualinformation. Direct line of sight is often only available through small, thickwindows, which often become discoloured and less transparent over time. Idealcamera locations are generally not possible, which can lead to areas of the cell notbeing visible, or at least difficult to see. Damage to the mobile, manipulator, toolor environment can be very expensive and dangerous.Despite the advances in the recent years of autonomous systems, the nuclearindustry prefers generally to ensure that there is a human in the loop. This is dueto the safety critical nature of the industry. Haptic interfaces provide a meansof allowing an operator to control aspects of a task that would be difficult orimpossible to control with impoverished visual feedback alone. Manipulator endeffectorforce control and mobile vehicle collision avoidance are examples of suchtasks.Haptic communication has been integrated with both a Schilling Titan II manipulatorteleoperation system and Cybermotion K2A mobile vehicle teleoperationsystem. The manipulator research was carried out using a real manipulatorwhereas the mobile research was carried out in simulation. Novel haptic communicationgeneration algorithms have been developed. Experiments have beenconducted using both the mobile and the manipulator to assess the performancegains offered by haptic communication.The results of the mobile vehicle experiments show that haptic feedback offeredperformance improvements in systems where the operator is solely responsible forcontrol of the vehicle. However in systems where the operator is assisted by semiautonomous behaviour that can perform obstacle avoidance, the advantages ofhaptic feedback were more subtle.The results from the manipulator experiments served to support the results fromthe mobile vehicle experiments since they also show that haptic feedback does notalways improve operator performance. Instead, performance gains rely heavily onthe nature of the task, other system feedback channels and operator assistancefeatures. The tasks performed with the manipulator were peg insertion, grindingand drilling
Conceptual room for ontic vagueness
No full textThis thesis is a systematic investigation of whether there might be conceptual room for the idea that the world itself might be vague, independently of how we describe it. This idea – the existence of so-called ontic vagueness – has generally been extremely unpopular in the literature; my thesis thus seeks to evaluate whether this ‘negative press’ is justified. I start by giving a working definition and semantics for ontic vagueness, and then attempt to show that there are no conclusive arguments that rule out vagueness of this kind. I subsequently establish what type of arguments I think would be most effective in establishing ontic vagueness and provide some arguments of this form. I then highlight a potential worry for this type of argument, but argue that it can be circumvented. Finally, I consider the main ways that the opponent of ontic vagueness would be likely resist the arguments I have offered, and argue that these strategies of response are methodologically problematic. I conclude by claiming that ontic vagueness is a perfectly plausible ontological commitment
Entanglement and quantity in quantum space - About quantum measurement (II)
No full textAs a continuation and extension of "quantity in phase space" "quantity in quantum space" is introduced. With that, the disappearing of quantum interference discussed in a previous paper [S. Durr, et al., Nature 395 (1998) 33] is explained in the same spirit as our recent papers [Ren De-Ming, Commun. Theor. Phys. (Beijing, China) 41 (2004) 685, 833].Physics, MultidisciplinarySCI(E)中国科学引文数据库(CSCD)1ARTICLE133-364
Sneutrino DM in the NMSSM with inverse seesaw mechanism
No full textIn supersymmetric theories like the Next-to-Minimal Supersymmetric Standard Model (NMSSM), the lightest neutralino with bino or singlino as its dominant component is customarily taken as dark matter (DM) candidate. Since light Higgsinos favored by naturalness can strength the couplings of the DM and thus enhance the DM-nucleon scattering rate, the tension between naturalness and DM direct detection results becomes more and more acute with the improved experimental sensitivity. In this work, we extend the NMSSM by inverse seesaw mechanism to generate neutrino mass, and show that in certain parameter space the lightest sneutrino may act as a viable DM candidate, i.e. it can annihilate by multi-channels to get correct relic density and meanwhile satisfy all experimental constraints. The most striking feature of the extension is that the DM-nucleon scattering rate can be naturally below its current experimental bounds regardless of the higgsino mass, and hence it alleviates the tension between naturalness and DM experiments. Other interesting features include that the Higgs phenomenology becomes much richer than that of the original NMSSM due to the relaxed constraints from DM physics and also due to the presence of extra neutrinos, and that the signatures of sparticles at colliders are quite different from those with neutralino as DM candidate.National Natural Science Foundation of China (NNSFC) [11575053]SCI(E)ARTICLE1
Classical mechanics and quantum mechanics
No full textThe Newton equation of motion is derived from quantum mechanics.Physics, MultidisciplinarySCI(E)中国科学引文数据库(CSCD)2ARTICLE5685-6884
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