8,608 research outputs found
Properties of isocalar-pair condensates
It is pointed out that the ground state of n neutrons and n protons in a
single-j shell, interacting through an isoscalar (T=0) pairing force, is not
paired, J=0, but rather spin-aligned, J=n. This observation is explained in the
context of a model of isoscalar P (J=1) pairs, which is mapped onto a system of
p bosons, leading to an approximate analytic solution of the isoscalar-pairing
limit in jj coupling.Comment: 7 pages, 3 figures, 1 tabl
In Memoriam: Daniel J. Meltzer
Sedan år 2006 har den syntetiskt framställda drogen spice existerat i Sverige, men först år 2008 blev drogen populär och tidningar började rikta uppmärksamhet mot den. Genom att drogen kan byta skepnad i uppbyggnaden kan den förbli laglig, därför kan egentligen namnet “spice” inte betraktas som ett enhetligt begrepp. Vårt syfte med denna studie blev att granska hur drogen spice beskrivs i tidningar och forskning. Även hur drogen betraktas gällande psykosociala och medicinska avseenden. Detta i förhållande till socialkonstruktivistiskt perspektiv. Den metod som vi valde att använda oss av i studien var kvantitativ innehållsanalys. Genom analys av 80 stycken svenska tidningsartiklar hämtade ur databasen mediearkivet, samt vetenskapliga artiklar och litteratur har vi besvarat våra frågeställningar. De resultat vi fick från analyser visade på att tidningar kan vara av betydande roll för ungdomars attityder. Tidningar kan utföra bland annat skrämselpropaganda för att upplysa och förhindra brukandet av spice, dessvärre visar resultatet en motsatt effekt. Forskning visar att bruk av spice kan påverka relationer och arbete negativt. Dessutom är några bieffekter av spice bröstsmärtor, vanföreställningar, självmordstankar och hjärtstopp
Xenon Bubble Chambers for Direct Dark Matter Detection
The search for dark matter is one of today's most exciting fields. As bigger
detectors are being built to increase their sensitivity, background reduction
is an ever more challenging issue. To this end, a new type of dark matter
detector is proposed, a xenon bubble chamber, which would combine the strengths
of liquid xenon TPCs, namely event by event energy resolution, with those of a
bubble chamber, namely insensitivity to electronic recoils. In addition, it
would be the first time ever that a dark matter detector is active on all three
detection channels, ionization and scintillation characteristic of xenon
detectors, and heat through bubble formation in superheated fluids. Preliminary
simulations show that, depending on threshold, a discrimination of 99.99\% to
99.9999+\% can be achieved, which is on par or better than many current
experiments. A prototype is being built at the University at Albany, SUNY. The
prototype is currently undergoing seals, thermal, and compression testing.Comment: 11 pages, 6 pages, LIDINE 2015 proceedin
The Emotional and Practical Experiences of Formula-Feeding Mothers
The majority of infant‐feeding research is focused on identifying mother's reasons for the cessation of breastfeeding. The experience of mothers who choose to use formula is largely overlooked in quantitative designs. This study aimed to describe the emotional and practical experiences of mothers who formula feed in any quantity, and examine whether these experiences would vary among different cohorts of formula‐feeding mothers according to prenatal feeding intention and postnatal feeding method. A total of 890 mothers of infants up to 26 weeks of age, who were currently formula feeding in any quantity, were recruited through relevant international social media sites via advertisements providing a link to an online survey. Predictors of emotional experiences included guilt, stigma, satisfaction, and defense as a result of their infant feeding choices. Practical predictor variables included support received from health professionals, respect displayed by their everyday environment, and main sources of infant feeding information. Descriptive findings from the overall sample highlighted a worryingly high percentage of mother's experienced negative emotions as a result of their decision to use formula. Multinomial logit models revealed that negative emotions such as guilt, dissatisfaction, and stigma were directly associated with feeding intention and method. The evidence suggests that the current approach to infant‐feeding promotion and support may be paradoxically related to significant issues with emotional well‐being. These findings support criticisms of how infant‐feeding recommendations are framed by health care professionals and policy makers, and highlight a need to address formula feeding in a more balanced, woman‐centered manner
Graphitization of small carbonate samples for paleoceanographic research at the godwin radiocarbon laboratory, University of Cambridge
AbstractA new radiocarbon preparation facility was set up in 2010 at the Godwin Laboratory for Palaeoclimate Research, at the University of Cambridge. Samples are graphitized via hydrogen reduction on an iron powder catalyst before being sent to the Chrono Centre, Belfast, or the Australian National University for accelerator mass spectrometry (AMS) analysis. The experimental setup and procedure have recently been developed to investigate the potential for running small samples of foraminiferal carbonate. By analyzing background values of samples ranging from 0.04 to 0.6 mg C along with similar sized secondary standards, the setup and experimental procedures were optimized for small samples. “Background” modern 14C contamination has been minimized through careful selection of iron powder, and graphitization has been optimized through the use of “small volume” reactors, allowing samples containing as little as 0.08 mg C to be graphitized and accurately dated. Graphitization efficiency/fractionation is found not to be the main limitation on the analysis of samples smaller than 0.07 mg C, which rather depends primarily on AMS ion beam optics, suggesting further improvements in small sample analysis might yet be achieved with our methodology.We would like to thank James Rolfe for running the stable isotope measurements, as well as the Royal Society and NERC grant NE/L006421/1 for research support.This is the author accepted manuscript. The final version is available from Cambridge University Press via http://dx.doi.org/10.1017/RDC.2015.
A transmission electron microscope study of N\'eel skyrmion magnetic textures in multilayer thin film systems with large interfacial chiral interaction
Skyrmions in ultrathin ferromagnetic metal (FM)/heavy metal (HM) multilayer
systems produced by conventional sputtering methods have recently generated
huge interest due to their applications in the field of spintronics. The
sandwich structure with two correctly-chosen heavy metal layers provides an
additive interfacial exchange interaction which promotes domain wall or
skyrmion spin textures that are N\'eel in character and with a fixed chirality.
Lorentz transmission electron microscopy (TEM) is a high resolution method
ideally suited to quantitatively image such chiral magnetic configurations.
When allied with physical and chemical TEM analysis of both planar and
cross-sectional samples, key length scales such as grain size and the chiral
variation of the magnetisation variation have been identified and measured. We
present data showing the importance of the grain size (mostly < 10nm) measured
from direct imaging and its potential role in describing observed behaviour of
isolated skyrmions (diameter < 100nm). In the latter the region in which the
magnetization rotates is measured to be around 30 nm. Such quantitative
information on the multiscale magnetisation variations in the system is key to
understanding and exploiting the behaviour of skyrmions for future device
applications.Comment: 11 pages , 6 figures, journal articl
Treatment of ongoing autoimmune encephalomyelitis with activated B-cell progenitors maturing into regulatory B cells.
The influence of signals perceived by immature B cells during their development in bone marrow on their subsequent functions as mature cells are poorly defined. Here, we show that bone marrow cells transiently stimulated in vivo or in vitro through the Toll-like receptor 9 generate proB cells (CpG-proBs) that interrupt experimental autoimmune encephalomyelitis (EAE) when transferred at the onset of clinical symptoms. Protection requires differentiation of CpG-proBs into mature B cells that home to reactive lymph nodes, where they trap T cells by releasing the CCR7 ligand, CCL19, and to inflamed central nervous system, where they locally limit immunopathogenesis through interleukin-10 production, thereby cooperatively inhibiting ongoing EAE. These data demonstrate that a transient inflammation at the environment, where proB cells develop, is sufficient to confer regulatory functions onto their mature B-cell progeny. In addition, these properties of CpG-proBs open interesting perspectives for cell therapy of autoimmune diseases
Relative spins and excitation energies of superdeformed bands in 190Hg: Further evidence for octupole vibration
An experiment using the Eurogam Phase II gamma-ray spectrometer confirms the
existence of an excited superdeformed (SD) band in 190Hg and its very unusual
decay into the lowest SD band over 3-4 transitions. The energies and dipole
character of the transitions linking the two SD bands have been firmly
established. Comparisons with RPA calculations indicate that the excited SD
band can be interpreted as an octupole-vibrational structure.Comment: 12 pages, latex, 4 figures available via WWW at
http://www.phy.anl.gov/bgo/bc/hg190_nucl_ex.htm
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