140 research outputs found
Comparative historical sociology and the State : problems of method
Historical sociology can be understood both as a specific sub-field of sociology and as providing general conceptual underpinnings of the discipline, to the extent that it provides an understanding of the specificity of the modern state and the perceived emergence of modernity within Europe. The association of modernity with Europe (and with a European history limited to the self-identified boundaries of the continent) is commonplace and pervasive within the social sciences and humanities. What such an understanding fails to take into consideration, however, are the connections between Europe and the rest of the world that constitute the broader context for the emergence of what is understood to be the modern world and its institutions, such as the state and market. In this article, I suggest that integral to this misunderstanding, and its reproduction over time, is the methodology of comparative historical sociology as represented by ideal types. In contrast, I argue for âconnected sociologiesâ as a more appropriate way to understand our shared past and its continuing impact upon the present. I examine these issues in the context of historical sociological understandings of nation-state formation
The YARHG Domain: An Extracellular Domain in Search of a Function
We have identified a new bacterial protein domain that we hypothesise binds to peptidoglycan. This domain is called the YARHG domain after the most highly conserved sequence-segment. The domain is found in the extracellular space and is likely to be composed of four alpha-helices. The domain is found associated with protein kinase domains, suggesting it is associated with signalling in some bacteria. The domain is also found associated with three different families of peptidases. The large number of different domains that are found associated with YARHG suggests that it is a useful functional module that nature has recombined multiple times
Search for the pentaquark in the reaction
A search for the \thp in the reaction was completed
using the CLAS detector at Jefferson Lab. A study of the same reaction,
published earlier, reported the observation of a narrow \thp resonance. The
present experiment, with more than 30 times the integrated luminosity of our
earlier measurement, does not show any evidence for a narrow pentaquark
resonance. The angle-integrated upper limit on \thp production in the mass
range of 1.52 to 1.56 GeV/c for the reaction is
0.3 nb (95% CL). This upper limit depends on assumptions made for the mass and
angular distribution of \thp production. Using \lamstar production as an
empirical measure of rescattering in the deuteron, the cross section upper
limit for the elementary reaction is estimated to be
a factor of 10 higher, {\it i.e.}, nb (95% CL).Comment: 5 figures, submitted to PRL, revised for referee comment
Photodisintegration of He into p+t
The two-body photodisintegration of He into a proton and a triton has
been studied using the CEBAF Large-Acceptance Spectrometer (CLAS) at Jefferson
Laboratory. Real photons produced with the Hall-B bremsstrahlung-tagging system
in the energy range from 0.35 to 1.55 GeV were incident on a liquid He
target. This is the first measurement of the photodisintegration of He
above 0.4 GeV. The differential cross sections for the He
reaction have been measured as a function of photon-beam energy and
proton-scattering angle, and are compared with the latest model calculations by
J.-M. Laget. At 0.6-1.2 GeV, our data are in good agreement only with the
calculations that include three-body mechanisms, thus confirming their
importance. These results reinforce the conclusion of our previous study of the
three-body breakup of He that demonstrated the great importance of
three-body mechanisms in the energy region 0.5-0.8 GeV .Comment: 13 pages submitted in one tgz file containing 2 tex file and 22
postscrip figure
photoproduction on the proton for photon energies from 0.675 to 2.875 GeV
Differential cross sections for the reaction have been
measured with the CEBAF Large Acceptance Spectrometer (CLAS) and a tagged
photon beam with energies from 0.675 to 2.875 GeV. The results reported here
possess greater accuracy in the absolute normalization than previous
measurements. They disagree with recent CB-ELSA measurements for the process at
forward scattering angles. Agreement with the SAID and MAID fits is found below
1 GeV. The present set of cross sections has been incorporated into the SAID
database, and exploratory fits have been extended to 3 GeV. Resonance couplings
have been extracted and compared to previous determinations.Comment: 18 pages, 48 figure
Exclusive electroproduction on the proton at CLAS
The reaction has been measured, using the 5.754
GeV electron beam of Jefferson Lab and the CLAS detector. This represents the
largest ever set of data for this reaction in the valence region. Integrated
and differential cross sections are presented. The , and
dependences of the cross section are compared to theoretical calculations based
on -channel meson-exchange Regge theory on the one hand and on quark handbag
diagrams related to Generalized Parton Distributions (GPDs) on the other hand.
The Regge approach can describe at the 30% level most of the features
of the present data while the two GPD calculations that are presented in this
article which succesfully reproduce the high energy data strongly underestimate
the present data. The question is then raised whether this discrepancy
originates from an incomplete or inexact way of modelling the GPDs or the
associated hard scattering amplitude or whether the GPD formalism is simply
inapplicable in this region due to higher-twists contributions, incalculable at
present.Comment: 29 pages, 29 figure
First Measurement of Beam-Recoil Observables Cx and Cz in Hyperon Photoproduction
Spin transfer from circularly polarized real photons to recoiling hyperons
has been measured for the reactions and
. The data were obtained using the CLAS
detector at Jefferson Lab for center-of-mass energies between 1.6 and 2.53
GeV, and for . For the , the
polarization transfer coefficient along the photon momentum axis, , was
found to be near unity for a wide range of energy and kaon production angles.
The associated transverse polarization coefficient, , is smaller than
by a roughly constant difference of unity. Most significantly, the {\it
total} polarization vector, including the induced polarization ,
has magnitude consistent with unity at all measured energies and production
angles when the beam is fully polarized. For the this simple
phenomenology does not hold. All existing hadrodynamic models are in poor
agreement with these results.Comment: 28 pages, 18 figures, Submitted to Physical Review
Identifying sources of strength: resilience from the perspective of older people receiving long-term community care
This study seeks to explore the sources of strength giving rise to resilience among older people. Twenty-nine in-depth interviews were conducted with older people who receive long-term community care. The interviews were subjected to a thematic content analysis. The findings suggest that the main sources of strength identified among older people were constituted on three domains of analysis; the individual-, interactional and contextual domain. The individual domain refers to the qualities within older people and comprises of three sub-domains, namely beliefs about oneâs competence, efforts to exert control and the capacity to analyse and understand ones situation. Within these subdomains a variety of sources of strength were found like pride about ones personality, acceptance and openness about ones vulnerability, the anticipation on future losses, mastery by practising skills, the acceptance of help and support, having a balanced vision on life, not adapting the role of a victim and carpe-diem. The interactional domain is defined as the way older people cooperate and interact with others to achieve their personal goals. Sources of strength on this domain were empowering (in)formal relationships and the power of giving. Lastly, the contextual domain refers to a broader political-societal level and includes sources of strength like the accessibility of care, the availability of material resources and social policy. The three domains were found to be inherently linked to each other. The results can be used for the development of positive, proactive interventions aimed at helping older people build on the positive aspects of their lives
Beam-Recoil Polarization Transfer in the Nucleon Resonance Region in the Exclusive and Reactions at CLAS
Beam-recoil transferred polarizations for the exclusive reactions have been measured using the CLAS
spectrometer at Jefferson Laboratory. New measurements have been completed at
beam energies of 4.261 and 5.754 GeV that span a range of momentum transfer
from 0.7 to 5.4 GeV, invariant energy from 1.6 to 2.6 GeV, and
the full center-of-mass angular range of the meson. These new data add to
the existing CLAS measurements at 2.567 GeV, and provide the
first-ever data for the channel in electroproduction. Comparisons
of the data with several theoretical models are used to study the sensitivity
to s-channel resonance contributions and the underlying reaction mechanism.
Interpretations within two semi-classical partonic models are made to probe the
underlying reaction mechanism and the quark-pair creation dynamics.Comment: 48 pages, 22 figure
The extraction of total cross section from
We report on the first measurement of the differential cross section of
-meson photoproduction for the exclusive
reaction channel. The experiment was performed using a
\textcolor{black}{tagged-photon} beam and the CEBAF Large Acceptance
Spectrometer (CLAS) at Jefferson Lab. A combined analysis using data from the
channel and those from a previous publication on
coherent production on the deuteron has been carried out to extract the
total cross section, . The extracted total
cross section favors a value above 20 mb. This value is larger than the value
extracted using vector-meson dominance models for photoproduction on the
proton.Comment: 7 pages 4 figure
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