3,478 research outputs found
Lifetime of 19Ne*(4.03 MeV)
The Doppler-shift attenuation method was applied to measure the lifetime of
the 4.03 MeV state in 19Ne. Utilizing a 3He-implanted Au foil as a target, the
state was populated using the 20Ne(3He,alpha)19Ne reaction in inverse
kinematics at a 20Ne beam energy of 34 MeV. De-excitation gamma rays were
detected in coincidence with alpha particles. At the 1 sigma level, the
lifetime was determined to be 11 +4, -3 fs and at the 95.45% confidence level
the lifetime is 11 +8, -7 fs.Comment: 6 pages, submitted to Phys. Rev.
Testing cosmological variability of the proton-to-electron mass ratio using the spectrum of PKS 0528-250
Multidimensional cosmologies allow for variations of fundamental physical
constants over the course of cosmological evolution, and different versions of
the theories predict different time dependences. In particular, such variations
could manifest themselves as changes of the proton-to-electron mass ratio
\mu=m_p/m_e over the period of ~ 10^{10} years since the moment of formation of
high-redshift QSO spectra. Here we analyze a new, high-resolution spectrum of
the z=2.81080 molecular hydrogen absorption system toward the quasar PKS
0528-250 to derive a new observational constraint to the time-averaged
variation rate of the proton-to-electron mass ratio. We find |\dot{\mu} / \mu|
< 1.5 \times 10^{-14}/year, which is much tighter than previously measured
limits.Comment: 9 pages, 2 tables, 3 figures, LaTeX (aas2pp4.sty and epsf.sty
included). To be published in Ap
Coding and regulatory variants are associated with serum protein levels and disease.
Circulating proteins can be used to diagnose and predict disease-related outcomes. A deep serum proteome survey recently revealed close associations between serum protein networks and common disease. In the current study, 54,469 low-frequency and common exome-array variants were compared to 4782 protein measurements in the serum of 5343 individuals from the AGES Reykjavik cohort. This analysis identifies a large number of serum proteins with genetic signatures overlapping those of many diseases. More specifically, using a study-wide significance threshold, we find that 2021 independent exome array variants are associated with serum levels of 1942 proteins. These variants reside in genetic loci shared by hundreds of complex disease traits, highlighting serum proteins' emerging role as biomarkers and potential causative agents of a wide range of diseases
Content analysis of elite articulations
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67140/2/10.1177_002200276400800406.pd
Eight common genetic variants associated with serum dheas levels suggest a key role in ageing mechanisms
Dehydroepiandrosterone sulphate (DHEAS) is the most abundant circulating steroid secreted by adrenal glands-yet its function is unknown. Its serum concentration declines significantly with increasing age, which has led to speculation that a relative DHEAS deficiency may contribute to the development of common age-related diseases or diminished longevity. We conducted a meta-analysis of genome-wide association data with 14,846 individuals and identified eight independent common SNPs associated with serum DHEAS concentrations. Genes at or near the identified loci include ZKSCAN5 (rs11761528; p = 3.15×10-36), SULT2A1 (rs2637125; p = 2.61×10-19), ARPC1A (rs740160; p = 1.56×10-16), TRIM4 (rs17277546; p = 4.50×10-11), BMF (rs7181230; p = 5.44×10-11), HHEX (rs2497306; p = 4.64×10-9), BCL2L11 (rs6738028; p = 1.72×10-8), and CYP2C9 (rs2185570; p = 2.29×10-8). These genes are associated with type 2 diabetes, lymphoma, actin filament assembly, drug and xenobiotic metabolism, and zinc finger proteins. Several SNPs were associated with changes in gene expression levels, and the related genes are connected to biological pathways linking DHEAS with ageing. This study provides much needed insight into the function of DHEAS
In search of the authentic nation: landscape and national identity in Canada and Switzerland
While the study of nationalism and national identity has flourished in the last decade, little attention has been devoted to the conditions under which natural environments acquire significance in definitions of nationhood. This article examines the identity-forming role of landscape depictions in two polyethnic nation-states: Canada and Switzerland. Two types of geographical national identity are identified. The first – what we call the ‘nationalisation of nature’– portrays zarticular landscapes as expressions of national authenticity. The second pattern – what we refer to as the ‘naturalisation of the nation’– rests upon a notion of geographical determinism that depicts specific landscapes as forces capable of determining national identity. The authors offer two reasons why the second pattern came to prevail in the cases under consideration: (1) the affinity between wild landscape and the Romantic ideal of pure, rugged nature, and (2) a divergence between the nationalist ideal of ethnic homogeneity and the polyethnic composition of the two societies under consideration
Outcome After Therapeutic Lymph Node Dissection in Patients with Unknown Primary Melanoma Site
Purpose: The aim of this study was to evaluate the incidence and outcome of melanoma of unknown primary site (MUP) after therapeutic lymph node dissection (TLND) of palpable nodal melanoma metastases. Disease-free (DFS) and overall survival (OS) time of MUP patients were analyzed and compared to patients undergoing a TLND for known primary melanomas (MKP). Methods: This single institution retrospective study analyzed 342 consecutive patients who were treated with 415 TLNDs for palpable nodal disease from 1982 to 2009. Univariate and multivariate analyses included: MUP versus MKP, gender, Breslow thickness, ulceration of primary tumor, site of prima
75th Anniversary of ‘Existence of Electromagnetic-Hydrodynamic Waves’
We have recently passed the 75th anniversary of one of the most important
results in solar and space physics: Hannes Alfv\'en's discovery of Alfv\'en
waves and the Alfv\'en speed. To celebrate the anniversary, this article
recounts some major episodes in the history of MHD waves. Following an
initially cool reception, Alfv\'en's ideas were propelled into the spotlight by
Fermi's work on cosmic rays, the new mystery of coronal heating and, as
scientific perception of interplanetary space shifted dramatically and the
space race started, detection of Alfv\'en waves in the solar wind. From then
on, interest in MHD waves boomed, laying the foundations for modern remote
observations of MHD waves in the Sun, coronal seismology and some of today's
leading theories of coronal heating and solar wind acceleration. In 1970,
Alfv\'en received the Nobel Prize for his work in MHD, including these
discoveries. The article concludes with some reflection about what the history
implies about the way we do science, especially the advantages and pitfalls of
idealised mathematical models.Comment: 10 pages, accepted by Solar Physic
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