798 research outputs found
Social Capital and the Significance of Pre-Migration Context among Burmese Refugee Communities In Canada
What happens in the case of immigrant groups who have had such pre-migration experiences as to require specialized assistance in the adaptation process, and yet whose population is not substantial enough to convince governmental sources of funding their demands? The wave of Burmese refugees fleeing the 1988 crackdown in their country is one such example. Drawing from perspectives of Participatory Action Research (PAR), this study has several objectives. First, it explores the current settlement needs of the Burmese population by way of relating it to the pre-migration context. By identifying those characteristics which influence the ability of this group to effectively compete for resources among organized ethno-cultural groups in Canada, this study hopes to highlight barriers to full participation. Second, a related objective is the documentation of the settlement and integration issues faced by the Burmese population, namely through an exploratory study of experiences of Burmese communities in Winnipeg and Toronto. Third, it seeks to explore the question of social capital within the Burmese population and its possible implications for resettlement and integration process. Fourth, it will attempt to contribute to the testing of Participatory Action Research as a methodological tool in improving our understanding of refugee resettlement. And fifth, it seeks to generate recommendations that will improve the settlement and integration of this target population within Canadian society. Broadly, it is hoped that this study might demonstrate how the particular needs of immigrant groups, in this case statistically small ethno-cultural groups arriving with traumatic refugee experiences, require careful consideration in seeking to facilitate integration through enhanced social capital and self-help
Selective modulation of protein C affinity for EPCR and phospholipids by Gla domain mutation
Uniquely amongst vitamin K-dependent coagulation proteins, protein C interacts via its Gla domain both with a receptor, the endothelial cell protein C receptor (EPCR), and with phospholipids. We have studied naturally occurring and recombinant protein C Gla domain variants for soluble (s)EPCR binding, cell surface activation to activated protein C (APC) by the thrombin-thrombomodulin complex, and phospholipid dependent factor Va (FVa) inactivation by APC, to establish if these functions are concordant. Wild-type protein C binding to sEPCR was characterized with surface plasmon resonance to have an association rate constant of 5.23 x 10(5) m(-1).s(-1), a dissociation rate constant of 7.61 x 10(-2) s(-1) and equilibrium binding constant (K(D)) of 147 nm. It was activated by thrombin over endothelial cells with a K(m) of 213 nm and once activated to APC, rapidly inactivated FVa. Each of these interactions was dramatically reduced for variants causing gross Gla domain misfolding (R-1L, R-1C, E16D and E26K). Recombinant variants Q32A, V34A and D35A had essentially normal functions. However, R9H and H10Q/S11G/S12N/D23S/Q32E/N33D/H44Y (QGNSEDY) variants had slightly reduced (< twofold) binding to sEPCR, arising from an increased rate of dissociation, and increased K(m) (358 nm for QGNSEDY) for endothelial cell surface activation by thrombin. Interestingly, these variants had greatly reduced (R9H) or greatly enhanced (QGNSEDY) ability to inactivate FVa. Therefore, protein C binding to sEPCR and phospholipids is broadly dependent on correct Gla domain folding, but can be selectively influenced by judicious mutation
On Partial Compositeness and the CP asymmetry in charm decays
Recently, the LHCb and CDF collaborations reported the measure of an
unexpectedly large direct CP asymmetry in D meson decays. In this paper we ask
if new physics associated with Partial Compositeness could plausibly explain
this result. We find that Composite Higgs models with mass scale around 10 TeV
can account for it, while marginally satisfying all other flavor constraints in
the quark sector. The minimal framework is however inadequate in the lepton
sector due to the strong constraint from \mu\ to e \gamma. This tension can be
efficiently alleviated by realizing Partial Compositeness within Supersymmetry.
The resulting models can saturate the CP asymmetry in D decays for superpartner
masses close to the TeV scale and somewhat large A-terms. The supersymmetric
realization of Partial Compositeness also offers a predictive and
phenomenologically viable organizing principle for R-Parity violation, and may
result in very distinctive signatures at hadron colliders. With or without
Supersymmetry, the neutron EDM is expected to be around the present
experimental sensitivity.Comment: 35 pages, 2 tables, 3 figures. v2: published versio
Aspects of Split Supersymmetry
We explore some fundamental differences in the phenomenology, cosmology and
model building of Split Supersymmetry compared with traditional low-scale
supersymmetry. We show how the mass spectrum of Split Supersymmetry naturally
emerges from theories where the dominant source of supersymmetry breaking
preserves an symmetry, characterize the class of theories where the
unavoidable -breaking by gravity can be neglected, and point out a new
possibility, where supersymmetry breaking is directly communicated at tree
level to the visible sector via renormalizable interactions. Next, we discuss
possible low-energy signals for Split Supersymmetry. The absence of new light
scalars removes all the phenomenological difficulties of low-energy
supersymmetry, associated with one-loop flavor and CP violating effects.
However, the electric dipole moments of leptons and quarks do arise at two
loops, and are automatically at the level of present limits with no need for
small phases, making them accessible to several ongoing new-generation
experiments. We also study proton decay in the context of Split Supersymmetry,
and point out scenarios where the dimension-six induced decays may be
observable. Finally, we show that the novel spectrum of Split Supersymmetry
opens up new possibilities for the generation of dark matter, as the decays of
ultraheavy gravitinos in the early universe typically increase the abundance of
the lightest neutralino above its usual freeze-out value. This allows for
lighter gauginos and Higgsinos, more accessible both to the LHC and to
dark-matter detection experiments.Comment: 50 pages, references added, typos correcte
The human H5N1 influenza A virus polymerase complex is active in vitro over a broad range of temperatures, in contrast to the WSN complex, and this property can be attributed to the PB2 subunit
Influenza A virus (IAV) replicates in the upper respiratory tract of humans at 33 °C and in the intestinal tract of birds at close to 41 °C. The viral RNA polymerase complex comprises three subunits (PA, PB1 and PB2) and plays an important role in host adaptation. We therefore developed an in vitro system to examine the temperature sensitivity of IAV RNA polymerase complexes from different origins. Complexes were prepared from human lung epithelial cells (A549) using a novel adenoviral expression system. Affinity-purified complexes were generated that contained either all three subunits (PA/PB1/PB2) from the A/Viet/1203/04 H5N1 virus (H/H/H) or the A/WSN/33 H1N1 strain (W/W/W). We also prepared chimeric complexes in which the PB2 subunit was exchanged (H/H/W, W/W/H) or substituted with an avian PB2 from the A/chicken/Nanchang/3-120/01 H3N2 strain (W/W/N). All complexes were functional in transcription, cap-binding and endonucleolytic activity. Complexes containing the H5N1 or Nanchang PB2 protein retained transcriptional activity over a broad temperature range (30–42 °C). In contrast, complexes containing the WSN PB2 protein lost activity at elevated temperatures (39 °C or higher). The E627K mutation in the avian PB2 was not required for this effect. Finally, the avian PB2 subunit was shown to confer enhanced stability to the WSN 3P complex. These results show that PB2 plays an important role in regulating the temperature optimum for IAV RNA polymerase activity, possibly due to effects on the functional stability of the 3P complex
Line orientation adaptation: local or global?
Prolonged exposure to an oriented line shifts the perceived orientation of a subsequently observed line in the opposite direction, a phenomenon known as the tilt aftereffect (TAE). Here we consider whether the TAE for line stimuli is mediated by a mechanism that integrates the local parts of the line into a single global entity prior to the site of adaptation, or the result of the sum of local TAEs acting separately on the parts of the line. To test between these two alternatives we used the fact the TAE transfers almost completely across luminance contrast polarity [1]. We measured the TAE using adaptor and test lines that (1) either alternated in luminance polarity or were of a single polarity, and (2) either alternated in local orientation or were of a single orientation. We reasoned that if the TAE was agnostic to luminance polarity and was parts-based, we should obtain large TAEs using alternating-polarity adaptors with single-polarity tests. However we found that (i) TAEs using one-alternating-polarity adaptors with all-white tests were relatively small, increased slightly for two-alternating-polarity adaptors, and were largest with all-white or all-black adaptors. (ii) however TAEs were relatively large when the test was one-alternating polarity, irrespective of the adaptor type. (iii) The results with orientation closely mirrored those obtained with polarity with the difference that the TAE transfer across orthogonal orientations was weak. Taken together, our results demonstrate that the TAE for lines is mediated by a global shape mechanism that integrates the parts of lines into whole prior to the site of orientation adaptation. The asymmetry in the magnitude of TAE depending on whether the alternating-polarity lines was the adaptor or test can be explained by an imbalance in the population of neurons sensitive to 1st-and 2nd-order lines, with the 2nd-order lines being encoded by a subset of the mechanisms sensitive to 1st-order lines
Underwater Application of Quantitative PCR on an Ocean Mooring
The Environmental Sample Processor (ESP) is a device that allows for the underwater, autonomous application of DNA and protein probe array technologies as a means to remotely identify and quantify, in situ, marine microorganisms and substances they produce. Here, we added functionality to the ESP through the development and incorporation of a module capable of solid-phase nucleic acid extraction and quantitative PCR (qPCR). Samples collected by the instrument were homogenized in a chaotropic buffer compatible with direct detection of ribosomal RNA (rRNA) and nucleic acid purification. From a single sample, both an rRNA community profile and select gene abundances were ascertained. To illustrate this functionality, we focused on bacterioplankton commonly found along the central coast of California and that are known to vary in accordance with different oceanic conditions. DNA probe arrays targeting rRNA revealed the presence of 16S rRNA indicative of marine crenarchaea, SAR11 and marine cyanobacteria; in parallel, qPCR was used to detect 16S rRNA genes from the former two groups and the large subunit RuBisCo gene (rbcL) from Synecchococcus. The PCR-enabled ESP was deployed on a coastal mooring in Monterey Bay for 28 days during the spring-summer upwelling season. The distributions of the targeted bacterioplankon groups were as expected, with the exception of an increase in abundance of marine crenarchaea in anomalous nitrate-rich, low-salinity waters. The unexpected co-occurrence demonstrated the utility of the ESP in detecting novel events relative to previously described distributions of particular bacterioplankton groups. The ESP can easily be configured to detect and enumerate genes and gene products from a wide range of organisms. This study demonstrated for the first time that gene abundances could be assessed autonomously, underwater in near real-time and referenced against prevailing chemical, physical and bulk biological conditions
Isomer Spectroscopy of Neutron-rich 165,167Tb
Open Access JournalWe present information on the excited states in the prolate-deformed, neutron-rich nuclei 165;167Tb100;102. The nuclei of interest were synthesized following in-flight fission of a 345 MeV per nucleon 238U primary beam on a 2 mm 9Be target at the Radioactive Ion-Beam Factory (RIBF), RIKEN, Japan. The exotic nuclei were separated and identified event-by-event using the BigRIPS separator, with discrete energy gamma-ray decays from isomeric states with half-lives in the _s regime measured using the EURICA gamma-ray spectrometer. Metastable-state decays are identified in 165Tb and 167Tb and interpreted as arising from hindered E1 decay from the 7/2-[523] single quasi-proton Nilsson configuration to rotational states built on the 3/2-[411] single quasi-proton ground state. These data correspond to the first spectroscopic information in the heaviest, odd-A terbium isotopes reported to date and provide information on proton Nilsson configurations which reside close to the Fermi surface as the 170Dy doubly-midshell nucleus is approached.postprin
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