X-ray background and its correlation with the 21 cm signal

We use high resolution hydrodynamical simulations to study the contribution to the X-ray background from high-$z$ energetic sources, such as X-ray binaries, accreting nuclear black holes and shock heated interstellar medium. Adopting the model discussed in Eide et al. (2018), we find that these X-ray sources during the Epoch of Reionization (EoR) contribute less than a few percent of the unresolved X-ray background. The same sources contribute to less than $\sim$2\% of the measured angular power spectrum of the fluctuations of the X-ray background. The outputs of radiative transfer simulations modeling the EoR are used to evaluate the cross-correlations of X-ray background with the 21~cm signal from neutral hydrogen. Such correlation could be used to confirm the origin of the 21 cm signal, as well as give information on the properties of the X-ray sources during the EoR. We find that the correlations are positive during the early stages of reionization when most of the hydrogen is neutral, while they become negative when the intergalactic medium gets highly ionized, with the transition from positive to negative depending on both the X-ray model and the scale under consideration. With {\tt SKA} as the reference instrument for the 21~cm experiment, the predicted S/N for such correlations is $<1$ if the corresponding X-ray survey is only able to resolve and remove X-ray sources with observed flux $>10^{-15}\,\rm erg\, cm^{-2} \, s^{-1}$, while the cumulative S/N from $l=1000$ to $10^{4}$ at $x_{\rm HI}=0.5$ is $\sim 5$ if sources with observed flux $>10^{-17}\,\rm erg\, cm^{-2} \, s^{-1}$ are detected.Comment: 9 pages, 8 figure

Cerebrospinal fluid pulse pressure amplitude during lumbar infusion in idiopathic normal pressure hydrocephalus can predict response to shunting

<p>Abstract</p> <p>Background</p> <p>We have previously seen that idiopathic normal pressure hydrocephalus (iNPH) patients having elevated intracranial pressure (ICP) pulse amplitude consistently respond to shunt surgery. In this study we explored how the cerebrospinal fluid pressure (CSFP) pulse amplitude determined during lumbar infusion testing, correlates with ICP pulse amplitude determined during over-night ICP monitoring and with response to shunt surgery. Our goal was to establish a more reliable screening procedure for selecting iNPH patients for shunt surgery using lumbar intrathecal infusion.</p> <p>Methods</p> <p>The study population consisted of all iNPH patients undergoing both diagnostic lumbar infusion testing and continuous over-night ICP monitoring during the period 2002-2007. The severity of iNPH was assessed using our NPH grading scale before surgery and 12 months after shunting. The CSFP pulse was characterized from the amplitude of single pressure waves.</p> <p>Results</p> <p>Totally 62 iNPH patients were included, 45 of them underwent shunt surgery, in whom 78% were shunt responders. Among the 45 shunted patients, resistance to CSF outflow (R_out) was elevated (≥ 12 mmHg/ml/min) in 44. The ICP pulse amplitude recorded over-night was elevated (i.e. mean ICP wave amplitude ≥ 4 mmHg) in 68% of patients; 92% of these were shunt responders. In those with elevated overnight ICP pulse amplitude, we found also elevated CSFP pulse amplitude recorded during lumbar infusion testing, both during the opening phase following lumbar puncture and during a standardized period of lumbar infusion (15 ml Ringer over 10 min). The clinical response to shunting after 1 year strongly associated with the over-night ICP pulse amplitude, and also with the pulsatile CSFP during the period of lumbar infusion. Elevated CSFP pulse amplitude during lumbar infusion thus predicted shunt response with sensitivity of 88 and specificity of 60 (positive and negative predictive values of 89 and 60, respectively).</p> <p>Conclusions</p> <p>In iNPH patients, shunt response can be anticipated in 9/10 patients with elevated overnight ICP pulse amplitude, while in only 1/10 with low ICP pulse amplitude. Additionally, the CSFP pulse amplitude during lumbar infusion testing was elevated in patients with elevated over-night ICP pulse amplitude. In particular, measurement of CSFP pulse amplitude during a standardized infusion of 15 ml Ringer over 10 min was useful in predicting response to shunt surgery and can be used as a screening procedure for selection of iNPH patients for shunting.</p

The radiolarian fauna at the ice edge in the Greenland Sea during summer, 1988

Radiolaria were sampled from the plankton at 18 stations during two cruises in the Greenland Sea during summer, 1988. A total of 43 species or categories of radiolaria was found, but over 90% of the radiolarian fauna was dominated by adults or juveniles of 4 species: the spumellarian, Actinomma leptodermum and the nassellaria, Amphimelissa setosa, Pseudodictyophimus gracilipes, and Peridium longispinum. The stations sampled ranged from ice-covered areas high in nutrients to open water areas which were depleted in nutrients. These stations encompassed a gradient in the composition of the radiolarian fauna from an assemblage dominated by juveniles and adults of A. setosa and P. gracilipes at the ice edge to one dominated by Actinomma juveniles, A. leptodermum, and P. longispinum in open water. The total abundance of radiolaria correlated with integrated phaeopigment, but not with chlorophyll a. In discriminant function analysis the \u27ice edge\u27 radiolarian species listed above correlated well with chlorophyll a and phaeopigments, while the \u27open water\u27 species did not. Several water masses occur in the area, which complicates the interpretation considerably, but the data are consistent with the development of a radiolarian population in tempo with, and in all probability linked successionally to the development of the phytoplankton—microplankton bloom

Being an Educator: Norwegian Prison Officers’ Conception of their Role regarding Incarcerated Persons’ Education

Despite the fact that prison officers are close to the incarcerated persons in everyday life in prison, and therefore will have great impact and influence on the incarcerated persons’ understanding of and motivation for education and training in prison, we still know little about prison officers understanding of their professional role regarding incarcerated persons’ education. This article will investigate how Norwegian prison officers understand their importance as educational actors through the following research question: How do Norwegian prison officers understand their role as actors in incarcerated persons’ education? Building on qualitative interviews with 16 Norwegian prison officers’ the article analyses the role of prison officers from a broad educational perspective (Biesta, 2009; 2014; 2015; OECD, 2005; 2019). The analysis reveals that prison officers conduct work that enables incarcerated persons to master their own lives during the execution of and after completing their sentences. Although prison officers play a significant role in incarcerated persons’ education in prison, they are partly unaware of this role, and find that their own role is not in a collaborative relationship with other actors who facilitate incarcerated persons’ education

The pulsating brain: A review of experimental and clinical studies of intracranial pulsatility

The maintenance of adequate blood flow to the brain is critical for normal brain function; cerebral blood flow, its regulation and the effect of alteration in this flow with disease have been studied extensively and are very well understood. This flow is not steady, however; the systolic increase in blood pressure over the cardiac cycle causes regular variations in blood flow into and throughout the brain that are synchronous with the heart beat. Because the brain is contained within the fixed skull, these pulsations in flow and pressure are in turn transferred into brain tissue and all of the fluids contained therein including cerebrospinal fluid. While intracranial pulsatility has not been a primary focus of the clinical community, considerable data have accrued over the last sixty years and new applications are emerging to this day. Investigators have found it a useful marker in certain diseases, particularly in hydrocephalus and traumatic brain injury where large changes in intracranial pressure and in the biomechanical properties of the brain can lead to significant changes in pressure and flow pulsatility. In this work, we review the history of intracranial pulsatility beginning with its discovery and early characterization, consider the specific technologies such as transcranial Doppler and phase contrast MRI used to assess various aspects of brain pulsations, and examine the experimental and clinical studies which have used pulsatility to better understand brain function in health and with disease

Cross-correlation between the 21-cm signal and [OIII] emitters during early cosmic reionization

We study statistics of the 21-cm signal from the epoch of reionization. We propose to use [OIII] line emitting galaxies to cross-correlate with the 21-cm signal from $z = 7 - 10$. To this aim, we employ simulations of reionization obtained post-processing the high-resolution cosmological hydrodynamic simulation Massive Black-II with the three-dimensional (3D) radiative transfer code CRASH to follow the propagation of ionizing photons from a variety of sources. We show that, during the early phases of reionization, the 21-cm signal is positively correlated with the spatial distribution of the [OIII] emitters on large scales $(k < 1h~\rm cMpc^{-1})$. This positive correlation is generated by the temperature-galaxy correlation and it is a few times larger than when we assume that the heating is saturated. As the reionized regions expand, the correlation changes its sign to negative from $z = 10$ to 8. The signals at this epoch can be detected by combining the Square Kilometre Array (SKA) and a wide-field [OIII] emitter survey. We also calculate the cross-power spectrum with a 3D [OIII] intensity field, aiming at exploiting future intensity mapping observations. We conclude that high-redshift [OIII] line emitters can be used to probe the reionization process when the intergalactic medium is largely neutral.Comment: 7 pages, 5 figures, published in MNRA

Linking the High-Resolution Architecture of Modern and Ancient Wave-Dominated Deltas : Processes, Products and Forcing Factors

Many thoughts and concepts used in this paper were initially developed as a result of work conducted with funding provided to the WAVE Consortium at the Australian School of Petroleum, University of Adelaide (RBA, BKV and JB). The consortium sponsors (Apache, BAPETCO, BHPBP, BG, BP, Chevron, ConocoPhillips, Nexen, OMV, Shell, Statoil, Todd Energy, and Woodside Energy) are thus thanked for making this work possible. We are indebted to journal reviewers Cornel Olariu and Howard Feldman, and to Associate Editor Janok Bhattacharya for numerous comments and suggestions that improved the clarity of the manuscript.Peer reviewedPostprin