Partially Cooled Shocks: Detectable Precursors in the Warm/hot Intergalactic Medium

I present computations of the integrated column densities produced in the post-shock cooling layers and in the radiative precursors of partially cooled fast shocks as a function of the shock age. The results are applicable to the shock-heated warm/hot intergalactic medium which is expected to be a major baryonic reservoir and contain a large fraction of the so-called missing baryons. My computations indicate that readily observable amounts of intermediate and high ions, such as C IV, N V, and O VI, are created in the precursors of young shocks, for which the shocked gas remains hot and difficult to observe. I suggest that such precursors may provide a way to identify and estimate the "missing" baryonic mass associated with the shocks. The absorption-line signatures predicted here may be used to construct ion-ratio diagrams, which will serve as diagnostics for the photoionized gas in the precursors. In my numerical models, the time evolution of the shock structure, self-radiation, and associated metal-ion column densities are computed by a series of quasi-static models, each appropriate for a different shock age. The shock code used in this work calculates the non-equilibrium ionization and cooling, follows the radiative transfer of the shock self-radiation through the post-shock cooling layers, takes into account the resulting photoionization and heating rates, follows the dynamics of the cooling gas, and self-consistently computes the photoionization states in the precursor gas. I present a complete set of the age-dependent post-shock and precursor columns for all ionization states of the elements H, He, C, N, O, Ne, Mg, Si, S, and Fe as functions of the shock velocity, gas metallicity, and magnetic field. I present my numerical results in convenient online tables

Ion-by-ion Cooling efficiencies

We present ion-by-ion cooling efficiencies for low-density gas. We use Cloudy (ver. 08.00) to estimate the cooling efficiencies for each ion of the first 30 elements (H-Zn) individually. We present results for gas temperatures between 1e4 and 1e8K, assuming low densities and optically thin conditions. When nonequilibrium ionization plays a significant role the ionization states deviate from those that obtain in collisional ionization equilibrium (CIE), and the local cooling efficiency at any given temperature depends on specific non-equilibrium ion fractions. The results presented here allow for an efficient estimate of the total cooling efficiency for any ionic composition. We also list the elemental cooling efficiencies assuming CIE conditions. These can be used to construct CIE cooling efficiencies for non-solar abundance ratios, or to estimate the cooling due to elements not explicitly included in any nonequilibrium computation. All the computational results are listed in convenient online tables.Comment: Submitted to ApJS. Electronic data available at http://wise-obs.tau.ac.il/~orlyg/ion_by_ion

Metal-Ion Absorption in Conductively Evaporating Clouds

We present computations of the ionization structure and metal-absorption properties of thermally conductive interface layers that surround evaporating warm spherical clouds, embedded in a hot medium. We rely on the analytical formalism of Dalton & Balbus to calculate the temperature profile in the evaporating gas, and explicitly solve the time-dependent ionization equations for H, He, C, N, O, Si, and S in the interface. We include photoionization by an external field. We estimate how departures from equilibrium ionization affect the resonance-line cooling efficiencies in the evaporating gas, and determine the conditions for which radiative losses may be neglected in the solution for the evaporation dynamics and temperature profile. Our results indicate that non-equilibrium cooling significantly increases the value of the saturation parameter at which radiative losses begin to affect the flow dynamics. As applications we calculate the ion fractions and projected column densities arising in the evaporating layers surrounding dwarf-galaxy-scale objects that are also photoionized by metagalactic radiation. We compare our results to the UV metal-absorption column densities observed in local highly-ionized metal-absorbers, located in the Galactic corona or intergalactic medium. Conductive interfaces significantly enhance the formation of high-ions such as C^3+, N^4+, and O^5+ relative to purely photoionized clouds, especially for clouds embedded in a high-pressure corona. However, the enhanced columns are still too low to account for the O VI columns (~1e14 cm^-2) observed in the local high-velocity absorbers. We find that O VI columns larger than ~1e13 cm^-2 cannot be produced in evaporating clouds. Our results do support the conclusion of Savage & Lehner, that absorption due to evaporating O VI likely occurs in the local interstellar medium, with characteristic columns of ~1e13 cm^-2.Comment: Accepted for Publication in Ap

Narcissus's narcosis : formation of self, disintegration of self: a question of interactive entertainment and player - character identity correlation

Rozrywka interaktywna, jak żadne inne medium, pozwala widowni na aktywne uczestnictwo w świecie przedstawionym. W przeciwieństwie do klasycznie pojmowanego kina, teatru czy literatury, autor przestaje tutaj być wyłącznym twórcą i konstruktorem całości, stając się w pewnym sensie współuczestnikiem procesu twórczego – gracz zyskuje jednocześnie znacznie większe pole do kształtowania samej materii doświadczenia. By uczestniczyć w grze musimy jednak przyjąć pewne alter ego, które pozwoli nam na działanie w „magicznym kręgu”. Powstaje dzięki temu zupełnie nowy twór, z jednej strony kształtowany przez psychikę gracza, a z drugiej przez specyficzne środowisko świata wirtualnego. W niniejszej pracy autor analizuje powstały w ten sposób „amalgamat”, próbując odpowiedzieć na pytanie, czy rozrywka interaktywna jest rodzajem autobiograficznego komentarza ze strony samego gracza, czy też pozwala jedynie na eskapistyczne stłumienie własnego „ja”. Możliwości odnośnie do eksploracji własnej psychiki, jakie oferowane są przez gry komputerowe, mogą odegrać ogromną rolę w procesie kształtowania osobowości. Dobre zrozumienie tych procesów ważne jest nie tylko z przyczyn czysto akademickich, lecz także może przynieść ważne wnioski w dziedzinie psychologii i psychoterapii, a także ekonomii obecnego, zinformatyzowanego świata

Follow-Up among Homeless Patients at San Francisco General Hospital: Examining the Social Determinants of Health

The San Francisco General Hospital emergency department has a high occurrence of homeless patients that are lost to follow-up after discharge. This Doctor of Nursing Practice project conducted a survey to evaluate the social determinants of health among this population and how they influence the participant’s ability to follow-up. This is the first phase of a three-phase project involving assessment and evaluation. The second and third phases of this project will center on intervention and re-evaluation after intervention. The survey was administered to eligible participants who presented to the emergency department at San Francisco General Hospital. Fifty participants were surveyed on demographic information including their age, ethnicity, education, gender, income, and preferred language. Participants were then asked to rate economic stability, physical environment, education, food, community resources, and healthcare and how they impacted their ability to follow-up. Results from this survey showed economic stability, physical environment, and access to healthcare were the most commonly reported social determinants of health participants felt influenced their ability to follow-up. This evaluation showed that these social determinants of health necessitate consideration in this particular population

Operations for parallel satellite support

In the early preparation phase for the upcoming robotic dual-satellite DLR mission several technical and operational challenges presented themselves. The mission itself shall produce advanced scientific findings for the on-orbit servicing missions. One of the satellites includes a sophisticated robotic arm with automated as well as manual operation modes. Very restrictive robotic payload requirements with respect to ground station visibilities as well as the quality of the data link became a main driver for the ground data system design. The real-time control and feedback of the robotic arm represents the particular challenge. Analysis of these requirements as well as technical and operational solutions will be presented, whereas some results are based on the successful ROKVISS mission. The usage of a dual-uplink antenna is discussed with regard to parallel operations of two satellites, here again, with already existing results provided by operations of the TanDEM-X mission. The design of the ground communication network as well as possible solutions allowing parallel robotic and housekeeping operations is shown. Results of this mission analysis and preparation are not only valuable for particular robotic, but for all dual-satellite, high data rate or realtime communication missions

The Problems and Challenges of Modern Publishing and Printing Industry of Ukraine

In this article the author examines the main problems of the prospects of development and some questions of operation of publishing and printing industry within the frameworks of global digitalization and growth of digital publications. The author pays special attention to the priority of the objects of activity of the publishing and printing complex of Ukraine. The purpose of this work is to determine the possible ways of development of the publishing and printing industry of Ukraine on the basis of state regulation of their activities. The results of this work may be used by public institutions in predicting the effective development of the economy and national legislation to support publishing and printing industry