Molecular envelope around the HII region RCW 120

The H II region RCW 120 is a well-known object, which is often considered as a target to verify theoretical models of gas and dust dynamics in the interstellar medium. However, the exact geometry of RCW 120 is still a matter of debate. In this work, we analyse observational data on molecular emission in RCW 120 and show that 13CO(2-1) and C18O(2-1) lines are fitted by a 2D model representing a ring-like face-on structure. The changing of the C18O(3-2) line profile from double-peaked to single-peaked from the dense molecular Condensation 1 might be a signature of stalled expansion in this direction. In order to explain a self-absorption dip of the 13CO(2-1) and 13CO(3-2) lines, we suggest that RCW 120 is surrounded by a diffuse molecular cloud, and find confirmation of this cloud on a map of interstellar extinction. Optically thick 13CO(2-1) emission and the infrared 8 μm PAH band form a neutral envelope of the H II region resembling a ring, while the envelope breaks into separate clumps on images made with optically thin C18O(2-1) line and far-infrared dust emission. © 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Societ

Scaled momentum distributions for K-S(0) and Λ /̄ Λ in DIS at HERA

Scaled momentum distributions for the strange hadrons K0S and Λ/Λ¯ were measured in deep inelastic ep scattering with the ZEUS detector at HERA using an integrated luminosity of 330 pb−1. The evolution of these distributions with the photon virtuality, Q 2, was studied in the kinematic region 10 < Q 2  < 40000 GeV2 and 0.001 < x < 0.75, where x is the Bjorken scaling variable. Clear scaling violations are observed. Predictions based on different approaches to fragmentation were compared to the measurements. Leading-logarithm parton-shower Monte Carlo calculations interfaced to the Lund string fragmentation model describe the data reasonably well in the whole range measured. Next-to-leading-order QCD calculations based on fragmentation functions, FFs, extracted from e + e − data alone, fail to describe the measurements. The calculations based on FFs extracted from a global analysis including e + e −, ep and pp data give an improved description. The measurements presented in this paper have the potential to further constrain the FFs of quarks, anti-quarks and gluons yielding K0S and Λ/Λ¯ strange hadrons

A Model of 'Nonadditive' Routing Problem where the Costs Depend on the Set of Pending Tasks

We consider a generalization of the bottleneck (minimax) routing problem. The problem is to successively visit a number of megalopolises, complicated by precedence of constraints imposed on the order of megalopolises visited and the fact that the cost functions (of movement between megalopolises and of interior tasks) may explicitly depend on the list of tasks that are not completed at the present time. The process of movement is considered to be a sequence of steps, which include the exterior movement to the respective megalopolis and the following completion of (essentially interior) jobs connected with the megalopolis. The quality of the whole process is represented by the maximum cost of steps it consists of; the problem is to minimize the mentioned criterion (which yields a minimax problem, usually referred to as a 'bottleneck problem'). Optimal solutions, in the form of a route-track pair (a track, or trajectory, conforms to a specific instance of a tour over the megalopolises, which are numbered in accordance with the route; the latter is defined by the transposition of indices), are constructed through a 'nonstandard' variant of the dynamic programming method, which allows to avoid the process of constructing of all the values of the Bellman function whenever precedence constraints are present.Рассматривается следующий (усложненный) вариант маршрутной задачи >: исследуется задача последовательного обхода мегаполисов, осложненная условиями предшествования и тем, что функции стоимости (перемещений и внутренних работ) могут явным образом зависеть от списка заданий, которые не выполнены на данный момент. Процесс перемещений рассматривается в виде совокупности этапов, включающих внешнее перемещение к соответствующему мегаполису и последующее выполнение (внутренних по смыслу) работ, связанных с данным мегаполисом. Качество совокупного процесса оценивается максимумом стоимостей составляющих его этапов; рассматривается задача на минимум упомянутого критерия (получается задача на минимакс, обычно именуемая задачей >). Для построения оптимального решения в виде пары маршрут-трасса (трасса, или траектория, соответствует конкретному варианту прохождения мегаполисов, нумеруемых в соответствии с маршрутом, определяемым в виде перестановки индексов) построен > вариант метода динамического программирования, при реализации которого не используется, в случае ограничений в виде условий предшествования, построение всего массива значений функции Беллмана