655 research outputs found
Protest movements in colonial East Africa : aspects of early African response to European rule
Concepts of protest in Africa, like historical concepts elsewhere, have undergone considerable change through the last half century, and it is possible at present to distinguish three schools of thought. These are the colonialist school, the nationalist, and, for want of a more specific term, the revisionist.
For more information, refer to the Kenya National Archives subject guide.https://surface.syr.edu/archiveguidekenya/1010/thumbnail.jp
Polymeric Liquids in Nanoporous Photonic Structures: From Precursor Film Spreading to Imbibition Dynamics at the Nanoscale
Polymers are known to wet nanopores with high surface energy through an
atomically thin precursor film followed by slower capillary filling. We present
here light interference spectroscopy using a nanoporous membrane-based chip
that allows us to observe the dynamics of these phenomena in situ with
sub-nanometer spatial and milli- to microsecond temporal resolution. The device
consists of a mesoporous silicon film (average pore size 6 nm) with an
integrated photonic crystal, which permits to simultaneously measure the phase
shift of the thin-film interference and the resonance of the photonic crystal
upon imbibition. For a styrene dimer, we find a flat fluid front without a
precursor film, while the pentamer forms an expanding molecular thin film
moving in front of the menisci of the capillary filling. These different
behaviors are attributed to a significantly faster pore-surface diffusion
compared to the imbibition dynamics for the pentamer and vice versa for the
dimer. In addition, both oligomers exhibit anomalously slow imbibition
dynamics, which could be explained by apparent viscosities of six and eleven
times the bulk value, respectively. However, a more consistent description of
the dynamics is achieved by a constriction model that emphasizes the increasing
importance of local undulations in the pore radius with the molecular size and
includes a sub-nanometer hydrodynamic dead, immobile zone at the pore wall, but
otherwise uses bulk fluid parameters. Overall, our study illustrates that
interferometric, opto-fluidic experiments with nanoporous media allow for a
remarkably detailed exploration of the nano-rheology of polymeric liquids.Comment: 9 pages, 5 figure
Library Cultures of Data Curation: Adventures in Astronomy
University libraries are partnering with disciplinary data producers to provide long-term digital curation of research datasets. Managing dataset producer expectations and guiding future development of library services requires understanding the decisions libraries make about curatorial activities, why they make these decisions, and the effects on future data reuse. We present a study, comprising interviews (n=43) and ethnographic observation, of two university libraries who partnered with the Sloan Digital Sky Survey (SDSS) collaboration to curate a significant astronomy dataset. The two libraries made different choices of the materials to curate and associated services, which resulted in different reuse possibilities. Each of the libraries offered partial solutions to the SDSS leaders’ objectives. The libraries’ approaches to curation diverged due to contextual factors, notably the extant infrastructure at their disposal (including technical infrastructure, staff expertise, values and internal culture, and organizational structure). The Data Transfer Process case offers lessons in understanding how libraries choose curation paths and how these choices influence possibilities for data reuse. Outcomes may not match data producers’ initial expectations but may create opportunities for reusing data in unexpected and beneficial ways
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Ulcerative colitis-risk loci on chromosomes 1p36 and 12q15 found by genome-wide association study.
Ulcerative colitis is a chronic inflammatory disease of the colon that presents as diarrhea and gastrointestinal bleeding. We performed a genome-wide association study using DNA samples from 1,052 individuals with ulcerative colitis and preexisting data from 2,571 controls, all of European ancestry. In an analysis that controlled for gender and population structure, ulcerative colitis loci attaining genome-wide significance and subsequent replication in two independent populations were identified on chromosomes 1p36 (rs6426833, combined P = 5.1 x 10(-13), combined odds ratio OR = 0.73) and 12q15 (rs1558744, combined P = 2.5 x 10(-12), combined OR = 1.35). In addition, combined genome-wide significant evidence for association was found in a region spanning BTNL2 to HLA-DQB1 on chromosome 6p21 (rs2395185, combined P = 1.0 x 10(-16), combined OR = 0.66) and at the IL23R locus on chromosome 1p31 (rs11209026, combined P = 1.3 x 10(-8), combined OR = 0.56; rs10889677, combined P = 1.3 x 10(-8), combined OR = 1.29)
Differential (2+1) Jet Event Rates and Determination of alpha_s in Deep Inelastic Scattering at HERA
Events with a (2+1) jet topology in deep-inelastic scattering at HERA are
studied in the kinematic range 200 < Q^2< 10,000 GeV^2. The rate of (2+1) jet
events has been determined with the modified JADE jet algorithm as a function
of the jet resolution parameter and is compared with the predictions of Monte
Carlo models. In addition, the event rate is corrected for both hadronization
and detector effects and is compared with next-to-leading order QCD
calculations. A value of the strong coupling constant of alpha_s(M_Z^2)=
0.118+- 0.002 (stat.)^(+0.007)_(-0.008) (syst.)^(+0.007)_(-0.006) (theory) is
extracted. The systematic error includes uncertainties in the calorimeter
energy calibration, in the description of the data by current Monte Carlo
models, and in the knowledge of the parton densities. The theoretical error is
dominated by the renormalization scale ambiguity.Comment: 25 pages, 6 figures, 3 tables, submitted to Eur. Phys.
Multiplicity Structure of the Hadronic Final State in Diffractive Deep-Inelastic Scattering at HERA
The multiplicity structure of the hadronic system X produced in
deep-inelastic processes at HERA of the type ep -> eXY, where Y is a hadronic
system with mass M_Y< 1.6 GeV and where the squared momentum transfer at the pY
vertex, t, is limited to |t|<1 GeV^2, is studied as a function of the invariant
mass M_X of the system X. Results are presented on multiplicity distributions
and multiplicity moments, rapidity spectra and forward-backward correlations in
the centre-of-mass system of X. The data are compared to results in e+e-
annihilation, fixed-target lepton-nucleon collisions, hadro-produced
diffractive final states and to non-diffractive hadron-hadron collisions. The
comparison suggests a production mechanism of virtual photon dissociation which
involves a mixture of partonic states and a significant gluon content. The data
are well described by a model, based on a QCD-Regge analysis of the diffractive
structure function, which assumes a large hard gluonic component of the
colourless exchange at low Q^2. A model with soft colour interactions is also
successful.Comment: 22 pages, 4 figures, submitted to Eur. Phys. J., error in first
submission - omitted bibliograph
Measurements of Transverse Energy Flow in Deep-Inelastic Scattering at HERA
Measurements of transverse energy flow are presented for neutral current
deep-inelastic scattering events produced in positron-proton collisions at
HERA. The kinematic range covers squared momentum transfers Q^2 from 3.2 to
2,200 GeV^2, the Bjorken scaling variable x from 8.10^{-5} to 0.11 and the
hadronic mass W from 66 to 233 GeV. The transverse energy flow is measured in
the hadronic centre of mass frame and is studied as a function of Q^2, x, W and
pseudorapidity. A comparison is made with QCD based models. The behaviour of
the mean transverse energy in the central pseudorapidity region and an interval
corresponding to the photon fragmentation region are analysed as a function of
Q^2 and W.Comment: 26 pages, 8 figures, submitted to Eur. Phys.
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