Simultaneous energy and mass calibration of large-radius jets with the ATLAS detector using a deep neural network

The energy and mass measurements of jets are crucial tasks for the Large Hadron Collider experiments. This paper presents a new calibration method to simultaneously calibrate these quantities for large-radius jets measured with the ATLAS detector using a deep neural network (DNN). To address the specificities of the calibration problem, special loss functions and training procedures are employed, and a complex network architecture, which includes feature annotation and residual connection layers, is used. The DNN-based calibration is compared to the standard numerical approach in an extensive series of tests. The DNN approach is found to perform significantly better in almost all of the tests and over most of the relevant kinematic phase space. In particular, it consistently improves the energy and mass resolutions, with a 30% better energy resolution obtained for transverse momenta pT > 500 GeV

Physiological system analysis of the kidney by high-temporal-resolution T(2)* monitoring of an oxygenation step response

PURPOSE: Examine the feasibility of characterizing the regulation of renal oxygenation using high-temporal-resolution monitoring of the T(2)* response to a step-like oxygenation stimulus. METHODS: For T(2)* mapping, multi-echo gradient-echo imaging was used (temporal resolution = 9 seconds). A step-like renal oxygenation challenge was applied involving sequential exposure to hyperoxia (100% O(2)), hypoxia (10% O(2) + 90% N(2)), and hyperoxia (100% O(2)). In vivo experiments were performed in healthy rats (N = 10) and in rats with bilateral ischemia-reperfusion injury (N = 4). To assess the step response of renal oxygenation, a second-order exponential model was used (model parameters: amplitude [A], time delay [Δt], damping constant [D], and period of the oscillation [T]) for renal cortex, outer stripe of the outer medulla, inner stripe of the outer medulla, and inner medulla. RESULTS: The second-order exponential model permitted us to model the exponential T(2)* recovery and the superimposed T(2)* oscillation following renal oxygenation stimulus. The in vivo experiments revealed a difference in D(outer medulla) between healthy controls (D 1, reflecting aperiodic recovery). The increase in D(outer medulla) by a factor of 3.7 (outer stripe of the outer medulla) and 10.0 (inner stripe of the outer medulla) suggests that this parameter might be rather sensitive to (patho)physiological oxygenation changes. CONCLUSION: This study demonstrates the feasibility of monitoring the dynamic oxygenation response of renal tissues to a step-like oxygenation challenge using high-temporal-resolution T(2)* mapping. Our results suggest that the implemented system analysis approach may help to unlock questions regarding regulation of renal oxygenation, with the ultimate goal of providing imaging means for diagnostics and therapy of renal diseases

Cross-Correlated TIRF/AFM Reveals Asymmetric Distribution of Force-Generating Heads along Self-Assembled, “Synthetic” Myosin Filaments

Myosin-II's rod-like tail drives filament assembly with a head arrangement that is often considered to be a symmetric bipole that generates equal and opposite contractile forces on actin. Self-assembled myosin filaments are shown here to be asymmetric in physiological buffer based on cross-correlated images from both atomic force microscopy and total internal reflection fluorescence. Quantitative cross-correlation of these orthogonal methods produces structural information unavailable to either method alone in showing that fluorescence intensity along the filament length is proportional to height. This implies that myosin heads form a shell around the filament axis, consistent with F-actin binding. A motor density of ∼50–100 heads/micrometer is further estimated but with an average of 32% more motors on one half of any given filament compared to the other, regardless of length. A purely entropic pyramidal lattice model is developed and mapped onto the Dyck paths problem that qualitatively captures this lack of length dependence and the distribution of filament asymmetries. Such strongly asymmetric bipoles are likely to produce an unbalanced contractile force in cells and in actin-myosin gels and thereby contribute to motility as well as cytoskeletal tension

Ethnic Migrant Workers and Emerging Ethnic Division in China's Urban Labor Market

China’s market transition has become a powerful integrative force, increasing social and economic interaction between the Han Chinese and ethnic minorities, by drawing various ethnic migrant workers into the urban labor market. In this article, we explore the ethnic dimension of migration and labor market dynamics, and compare wage earnings between ethnic minority and Han migrant workers in Kaili City in the Guizhou Province of China.The finding suggests that the labor market transition has increasingly put ethnic migrant workers at a disadvantage in the urban labor market in terms of wage earnings. With the economic restructuring from the 1990s to recent years, the earning gap between ethnic minority and Han migrant workers has widened. The study finds that the labor market experiences and outcomes of ethnic minority and Han migrant workers are quite similar