2,543 research outputs found
XMM-Newton observation of the Galactic supernova remnant W51C (G49.1-0.1)
The supernova remnant (SNR) W51C is a Galactic object located in a strongly
inhomogeneous interstellar medium with signs of an interaction of the SNR blast
wave with dense molecular gas. Diffuse X-ray emission from the interior of the
SNR can reveal element abundances in the different emission regions and shed
light on the type of supernova (SN) explosion and its progenitor. The hard
X-ray emission helps to identify possible candidates for a pulsar formed in the
SN explosion and for its pulsar wind nebula (PWN). We have analysed X-ray data
obtained with XMM-Newton. Spectral analyses in selected regions were performed.
Ejecta emission in the bright western part of the SNR, located next to a
complex of dense molecular gas, was confirmed. The Ne and Mg abundances suggest
a massive progenitor with a mass of > 20 M_sun. Two extended regions emitting
hard X-rays were identified (corresponding to the known sources [KLS2002] HX3
west and CXO J192318.5+140305 discovered with ASCA and Chandra, respectively),
each of which has an additional point source inside and shows a power-law
spectrum with Gamma ~ 1.8. Based on their X-ray emission, both sources can be
classified as PWN candidates.Comment: 6 pages, 4 figures, accepted for publication in Astronomy and
Astrophysic
Potassium channels in epithelial transport
Epithelial cells in the kidney, gastrointestinal tract and exocrine glands are engaged in vectorial transport of salt and nutrients. In these tissues, K+ channels play an important role for the stabilization of membrane voltage and maintenance of the driving force for electrogenic transport. Luminal K+ channels represent an exit pathway for the excretion of K+ in secreted fluid, urine and faeces, thereby effecting body K+ homeostasis. Indeed, the expression and function of several luminal K+ channels is modulated by hormones regulating water, Na+, and K+ metabolism. In addition to net transport of K+ in the serosal (or apical) direction, K+ channels can be coupled functionally to K+-transporting ATPases such as the basolateral Na+/K+ ATPase or the luminal H+/K+ ATPase. These ATPases export Na+ or H+ and take up K+, which is then recycled via K+ channels. This review gives a short overview on the molecular identity of epithelial K+ channels and summarizes the different mechanisms of K+ channel function during transport in epithelial cell
The Exegetical Basis for the Early Lutheran Doctrine of Baptismal Regeneration
This thesis was motivated by the question often raised in the classroom about the relation of faith to the regeneration in baptism. The question can be formulated in many ways. Is faith the presupposition for regeneration? What difference is there between faith and regeneration? Must faith precede baptism? What type of faith is given in baptism? What is faith without understanding of the Word of God? If baptism regenerates the infants who do not have preceding faith, what does baptism effect in the adult who already has faith? Can we still speak of regeneration in adult baptism? Or is baptism only a sign for the adult! Must baptism be regarded as a confession of faith
Left Recursion in Parsing Expression Grammars
Parsing Expression Grammars (PEGs) are a formalism that can describe all
deterministic context-free languages through a set of rules that specify a
top-down parser for some language. PEGs are easy to use, and there are
efficient implementations of PEG libraries in several programming languages.
A frequently missed feature of PEGs is left recursion, which is commonly used
in Context-Free Grammars (CFGs) to encode left-associative operations. We
present a simple conservative extension to the semantics of PEGs that gives
useful meaning to direct and indirect left-recursive rules, and show that our
extensions make it easy to express left-recursive idioms from CFGs in PEGs,
with similar results. We prove the conservativeness of these extensions, and
also prove that they work with any left-recursive PEG.
PEGs can also be compiled to programs in a low-level parsing machine. We
present an extension to the semantics of the operations of this parsing machine
that let it interpret left-recursive PEGs, and prove that this extension is
correct with regards to our semantics for left-recursive PEGs.Comment: Extended version of the paper "Left Recursion in Parsing Expression
Grammars", that was published on 2012 Brazilian Symposium on Programming
Language
Communication between Mentor and Mentee Using Videoconferencing in Surgical Training
Source at https://www.thinkmind.org/index.php?view=article&articleid=etelemed_2020_3_60_40023.In surgical training, mentors and mentees communicate to expand mentees’ technical skills. However, access to mentors for education in surgical subspecialties is a challenge in many hospitals. Videoconferencing (VC), which enables real-time communication between mentors and mentees in different geographical locations, can overcome this challenge. This study examines a practice in Norway in which VC is used to provide education on a specific laparoscopic surgical procedure. Specifically, the study explores the characteristics of communication between a mentor and mentee using VC and how it affected communication. The empirical material consists of video recordings of an educational trajectory that included eight patient cases and focus group meetings. The communication reveals knowledge gaps and their closure through establishment of a shared understanding. In this way, VC supported the learning of technical skills while enabling feedback on non-technical elements. Both the mentor and mentee could reach their full potentials—expanding their own communicative skills and reflecting on their own abilities. VC also affected the relationship between the mentor and mentee, who were peers and colleagues rather than participants in the traditional mentee–mentor relationship. The results of this study will enable the development of an activity for non-technical skills to become relevant using VC
Video Recordings of Interactions
Video recordings are an important resource for capturing in-dept social interaction and collaboration in workplace studies. Video-recorded observations can be used to analyse knowledge expansion in collaborative work when practitioners use videoconferences (VCs). Interaction analysis of a problem-solving activity is carried out, pointing to sequences in the work where knowledge expand, and problems are solved. Systematic observations using video recordings provide access to analysis of complex forms of interaction among professionals
New stationary phases for efficient separations and selectivity studies in anion chromatography
Spacer arm anion-exchange resins for single-column ion chromatography (SCIC) were prepared by a two-step procedure consisting of a bromoalkylation of Rohm & Haas XAD-1 resin under mild conditions, followed by amination with trimethylamine. The five resins prepared are all of a similar, low capacity and contain a one-, two-, three-, four- or six-carbon spacer arm linkage between the resin surface and the quaternary ammonium exchange group. The selectivity of these resins for mono- and divalent anions is evaluated and explained using classical ion-exchange theory. Separations are presented to demonstrate resin selectivity and to show the usefulness of these resins for practical ion chromatography;Trimethylammonium, tributylammonium and tributylphosphonium anion-exchange resins were synthesized and used for SCIC. The three resins were prepared using a 7 to 12 [mu]m polystyrene-divinylbenzene resin and are all of a similar, low capacity. The selectivity of these resins for mono- and divalent anions is examined and related to classical theory. It is shown that the unique selectivity obtained with the quaternary phosphonium resin is of practical value in the separation of anions;A new stationary phase for anion chromatography was prepared by a simple method of coating quaternized latex particles onto the surface of unsulfonated polymeric resins. A nonporous polystyrene resin of very uniform particle size is described that serves as an excellent substrate for the coated resins. These latex-coated resins are used to obtain highly efficient anion separations
Contested time: family-friendly working time policy in Germany and the United Kingdom
Access to family-friendly working time arrangements is unequally spread both within
and between workplaces, leaving many working parents with difficulties in combining
employment with family responsibilities. The British and German governments have
started to address this problem, but have done so in different ways. Focusing on time
allocation in the work/family interface and its implications for gender and employment
relations, this thesis explores the differences between the British and German
government strategies to improve access to family-friendly working time arrangements
for working parents, and how variation can be explained. As the flexibility
requirements of employers and employees often diverge and can be in conflict, the
thesis further investigates to what extent the German and British policy strategies were
designed to empower working parents to access the time flexibility they need. It
applies an empowerment perspective to the analysis of policy choice and design and
draws on the policy making literature to analyse cross-national variation.
Between 1997 and 2005, the incoming centre-left New Labour and ‘Red-Green’
governments both introduced information campaigns and employment rights to
improve access. The lack of economic incentives for the provision and take-up of
family-friendly working time arrangements reduced the overall empowering potential
of the British and German strategies. Although similar at the level of policy choice,
employment rights and information campaigns varied at the level of policy design with
different implications for access. The thesis concludes that family-friendly working
time policy did not achieve a significant redistribution of control over working time to
employees in either of the two countries. This can be in part explained by a strong
employer lobby and opportunities to influence policy choice and design, but also by
the ‘competitive advantage’ of childcare services over family-friendly working time
policy, directing government resources to more ‘employer-friendly’ reconciliation
policies
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