During extreme weather events, transportation networks−modeled as graphs G(V,E) consisting of a set of vertices V and a set of edges E−can be disrupted by bridge failures and wind-thrown trees, increasing the likelihood of disconnection between critical locations. Evaluating connectivity reliability between two vertices under probabilistic edge failures is a #P-complete problem, where exact analysis is generally limited to small graphs only. Quantum computing offers potential to accelerate these computations. While prior studies have formulated quantum approaches for undirected networks, the anticipated computational speedup has not been fully realized due to irreversibility of the connectivity computation. This study develops a quantum computational framework with a novel reversible computation technique for evaluating connectivity reliability in mixed graph networks−containing both one-way and two-way roads−commonly encountered in real transportation systems. The reversible logic enables the use of quantum amplitude estimation and phase estimation algorithms to achieve quadratic query-complexity improvement over crude Monte Carlo sampling. The corresponding query complexity scales as O(ϵ−1), and qubit requirement for modeling and computation is on the order of O(VlogV), where ϵ and V denote the precision of the reliability estimate and number of vertices, respectively. Validation of the proposed framework is performed on representative example graphs using Qiskit’s Aer simulator. The proposed approach establishes a quantum framework for hazard-induced connectivity reliability in mixed transportation networks and supports planning-oriented continuity assessment, although practical advantage awaits further hardware advances.
Scaphotrapeziotrapezoidal fracture-dislocations are extremely rare injuries, requiring early recognition and treatment. We present a case of a 54-year-old man with scaphotrapeziotrapezoidal fracture/dislocation following a motor vehicle accident, resulting in dorsal dislocation of the first and second carpal-metacarpal joints through the trapezium and trapezoid. The identification of the dislocation was delayed, and a month after the initial injury, fixation was attempted elsewhere but had redislocated at the first postoperative visit. Subsequent fixation was successful, using both radial and ulnar buried Kirschner wires. The clinical outcome was excellent with stable reduction maintained at 21 weeks postop.
The Southern Ocean accounts for >30% of the global ocean CO2 sink as a result of its solubility and biological pumps. To investigate the biological pump near Larsen C Ice Shelf (LCIS) in the Southern Ocean's western Weddell Sea, we measured the concentrations and nitrogen isotope ratios of nitrate, ammonium, and particulate organic nitrogen sampled in mid-summer 2019. From the isotope data, we estimate a mean f-ratio (i.e., fraction of primary production available for export from the mixed layer, equivalent to the extent of phytoplankton reliance on subsurface nitrate) of 0.81 +/- 0.18. This value is higher than parallel incubation-based f-ratio estimates (<= 0.5), a divergence that we ascribe to the different integration timescales of the two methods (weeks for the isotope method and hours to days for the incubations) and to a tendency for increased phytoplankton reliance on regenerated nitrogen later in the growth season. The carbon export flux estimated from the seasonal decline in nitrate concentration was >4.3 +/- 1.7 mol C m(-2) year(-1), as much as nine times that estimated for the open Antarctic Zone. Our data reveal that the waters adjacent to LCIS contribute disproportionately to the Weddell Sea's biological pump, which we attribute mainly to the effect of ice-melt on stratification and iron supply. The CO2 transferred by the biological pump into newly forming bottom waters will remain sequestered from the atmosphere for centuries.
Context. High-mass stars and star clusters form from the fragmentation of massive dense clumps driven by gravity, turbulence, and magnetic fields. The extent to which each of these agents impacts the fragmentation depending on the clump mass, density, and evolutionary stage is still largely unknown. Aims. The ALMA evolutionary study of high-mass protocluster formation in the GALaxy (ALMAGAL) project, with similar to 1000 clumps observed at similar to 1000 au resolution, allows a statistically significant characterization of the fragmentation process over a large range of clump physical parameters and evolutionary stages. Our goal is to characterize where and how the dense cores revealed by ALMA are distributed in massive potentially cluster-forming clumps to trace how fragmentation is initially set and how it proceeds before gas dispersal due to stellar feedback. Methods. We characterized the spatial distribution of dense cores in the 514 ALMAGAL clumps that host at least four cores, using a set of quantitative descriptors that we evaluated against the clump bolometric luminosity-to-mass ratio, which we adopted as an indicator of the evolution of the system. We measured the separations between cores with the minimum spanning tree (MST) method, which we compared with the predictions of gravitational fragmentation from Jeans theory. We investigated whether cores have specific arrangements using the Q parameter or variations due to their masses with the mass segregation ratio, Lambda(MSR). Results. ALMAGAL cores are distributed throughout the entire area of the clump, usually arranged in elliptical groups with an axis ratio e similar to 2.2, although high values with e >= 5 are also observed. We found a single characteristic core separation per clump in similar to 76% of cases, suggesting that multiple fragmentation lengths may be frequently present. Typical core separations are compatible with the clump-averaged thermal Jeans length,lambda(th)(J). However, we found an additional population of cores, typical of low-fragmented and young clumps, which are on average more widely separated with l approximate to 3 & times; lambda(th)(J). By stacking the distributions of the core separations in clumps of similar evolutionary stage, we also found that the separation decreases on average from l similar to 22 000 au in younger systems to l similar to 7000 au in more evolved ones. The ALMAGAL cores are typically distributed in fractal-type subclusters, while centrally concentrated patterns appear only at later stages, but we do not observe a progressive transition between these configurations with evolution. Finally, we also found 110 ALMAGAL systems with a signature of mass segregation, with an occurrence that increases with evolution.
