439 research outputs found
Principal infinity-bundles - General theory
The theory of principal bundles makes sense in any infinity-topos, such as
that of topological, of smooth, or of otherwise geometric
infinity-groupoids/infinity-stacks, and more generally in slices of these. It
provides a natural geometric model for structured higher nonabelian cohomology
and controls general fiber bundles in terms of associated bundles. For suitable
choices of structure infinity-group G these G-principal infinity-bundles
reproduce the theories of ordinary principal bundles, of bundle
gerbes/principal 2-bundles and of bundle 2-gerbes and generalize these to their
further higher and equivariant analogs. The induced associated infinity-bundles
subsume the notions of gerbes and higher gerbes in the literature.
We discuss here this general theory of principal infinity-bundles, intimately
related to the axioms of Giraud, Toen-Vezzosi, Rezk and Lurie that characterize
infinity-toposes. We show a natural equivalence between principal
infinity-bundles and intrinsic nonabelian cocycles, implying the classification
of principal infinity-bundles by nonabelian sheaf hyper-cohomology. We observe
that the theory of geometric fiber infinity-bundles associated to principal
infinity-bundles subsumes a theory of infinity-gerbes and of twisted
infinity-bundles, with twists deriving from local coefficient infinity-bundles,
which we define, relate to extensions of principal infinity-bundles and show to
be classified by a corresponding notion of twisted cohomology, identified with
the cohomology of a corresponding slice infinity-topos.
In a companion article [NSSb] we discuss explicit presentations of this
theory in categories of simplicial (pre)sheaves by hyper-Cech cohomology and by
simplicial weakly-principal bundles; and in [NSSc] we discuss various examples
and applications of the theory.Comment: 46 pages, published versio
At Sea Test 2 recovery cruise : Cruise 206 on board R/V Knorr April 10 - 15, 2012 Woods Hole - Woods Hole, MA
The R/V Knorr, on Cruise 206, carried out the recovery of three moorings for the Coastal
and Global Scale Nodes (CGSN) Implementing Organization of the NSF Ocean
Observatories Initiative. These three moorings are prototypes of the moorings to be used
by CGSN at the Pioneer, Endurance, and Global Arrays. Knorr departed from Woods
Hole, Massachusetts on April 10, 2012 and steamed south to the location of the mooring
deployments on the shelf break. Over five days, April 10-15, Knorr surveyed the bottom
at the planned mooring sites, recovered the moorings, and carried out preliminary
investigations of mechanical and electrical functionality on the recovered moorings and
mooring hardware, including observations of biofouling and corrosion. Knorr returned to
Woods Hole on April 15, 2012.Funding was provided by the National Science Foundation contract #SA9-10 through the
Consortium for Ocean Leadershi
WZW orientifolds and finite group cohomology
The simplest orientifolds of the WZW models are obtained by gauging a Z_2
symmetry group generated by a combined involution of the target Lie group G and
of the worldsheet. The action of the involution on the target is by a twisted
inversion g \mapsto (\zeta g)^{-1}, where \zeta is an element of the center of
G. It reverses the sign of the Kalb-Ramond torsion field H given by a
bi-invariant closed 3-form on G. The action on the worldsheet reverses its
orientation. An unambiguous definition of Feynman amplitudes of the orientifold
theory requires a choice of a gerbe with curvature H on the target group G,
together with a so-called Jandl structure introduced in hep-th/0512283. More
generally, one may gauge orientifold symmetry groups \Gamma = Z_2 \ltimes Z
that combine the Z_2-action described above with the target symmetry induced by
a subgroup Z of the center of G. To define the orientifold theory in such a
situation, one needs a gerbe on G with a Z-equivariant Jandl structure. We
reduce the study of the existence of such structures and of their inequivalent
choices to a problem in group-\Gamma cohomology that we solve for all simple
simply-connected compact Lie groups G and all orientifold groups \Gamma = Z_2
\ltimes Z.Comment: 48+1 pages, 11 figure
A Q-methodological study of 'smoking identities'
publication-status: Publishedtypes: ArticleIn contrast to the psychological literature on adolescent smoking, little research has investigated the social identities of adult smokers. This study aimed to identify shared âsmoking identitiesâ amongst a sample of 64 British smokers from different socio-economic groups using Q-methodology. Participants were asked to sort 70 items concerning smoking and smokers according to their agreement/disagreement with them. The 64 Q-sorts were then subjected to a by-person factor analysis yielding six factors, with the first four interpretable factors being presented here. Each factor is understood to represent a distinct âidentity positionâ. The first two, the âaddictedâ smoker, and the âin controlâ smoker, oriented around a biomedical model of smoking as an addictive health risk. The final two, the âno big dealâ smoker and the âproudâ smoker reflected alternative understandings and values. The identity positions also differed in the extent to which smoking was considered a core part of self-identity. Unpacking the âsmoking identitiesâ of current smokers offers the opportunity to devise targeted health promotion.Economic and Social Research Counci
Pityriasis rubra pilaris presenting with an abnormal autoimmune profile: two case reports
<p>Abstract</p> <p>Introduction</p> <p>Pityriasis rubra pilaris is an uncommon inflammatory and hyperproliferative dermatosis of juvenile or adult onset. The etiology of the disease is still unknown.</p> <p>Case presentation</p> <p>We present the cases of two Caucasian men aged 53 and 48 who presented with pityriasis rubra pillaris type 1; both patients also exhibited an abnormal immunological profile.</p> <p>Conclusion</p> <p>Pityriasis rubra pillaris is currently classified as a keratinization disorder. The abnormal immunological profile reported in our patients along with the comorbidity of pityriasis rubra pilaris with autoimmune disorders reported in the literature poses the question of a possible pathogenetic role for the immune response in this disorder.</p
Miscarriage and stillbirth following maternal Zika virus infection in nonhuman primates.
Zika virus (ZIKV) infection is associated with congenital defects and pregnancy loss. Here, we found that 26% of nonhuman primates infected with Asian/American ZIKV in early gestation experienced fetal demise later in pregnancy despite showing few clinical signs of infection. Pregnancy loss due to asymptomatic ZIKV infection may therefore be a common but under-recognized adverse outcome related to maternal ZIKV infection
The Rachel Carson Letters and the Making of Silent Spring
Environment, conservation, green, and kindred movements look back to Rachel Carsonâs 1962 book Silent Spring as a milestone. The impact of the book, including on government, industry, and civil society, was immediate and substantial, and has been extensively described; however, the provenance of the book has been less thoroughly examined. Using Carsonâs personal correspondence, this paper reveals that the primary source for Carsonâs book was the extensive evidence and contacts compiled by two biodynamic farmers, Marjorie Spock and Mary T. Richards, of Long Island, New York. Their evidence was compiled for a suite of legal actions (1957-1960) against the U.S. Government and that contested the aerial spraying of dichlorodiphenyltrichloroethane (DDT). During Rudolf Steinerâs lifetime, Spock and Richards both studied at Steinerâs Goetheanum, the headquarters of Anthroposophy, located in Dornach, Switzerland. Spock and Richards were prominent U.S. anthroposophists, and established a biodynamic farm under the tutelage of the leading biodynamics exponent of the time, Dr. Ehrenfried Pfeiffer. When their property was under threat from a government program of DDT spraying, they brought their case, eventually lost it, in the process spent US$100,000, and compiled the evidence that they then shared with Carson, who used it, and their extensive contacts and the trial transcripts, as the primary input for Silent Spring. Carson attributed to Spock, Richards, and Pfeiffer, no credit whatsoever in her book. As a consequence, the organics movement has not received the recognition, that is its due, as the primary impulse for Silent Spring, and it is, itself, unaware of this provenance
Phase Change Material for Thermotherapy of Buruli Ulcer: A Prospective Observational Single Centre Proof-of-Principle Trial
Buruli ulcer is an infection of the subcutaneous tissue leading to chronic necrotizing skin ulcers. The causative pathogen, Mycobacterium ulcerans, grows best at 30°Câ33°C and not above 37°C, and this property makes the application of heat a treatment option. We achieved a breakthrough in heat treatment of Buruli ulcer by employing the phase change material sodium acetate trihydrate as a heat application system for thermotherapy, which is widely used in commercial pocket heat pads. It is easy to apply, rechargeable in hot water, non-toxic and non-hazardous to the environment. Six laboratory reconfirmed patients with ulcerative Buruli lesions were included in the proof-of-principle study and treated for four to six weeks. In patients with small ulcers, wounds healed completely without further intervention. Patients with large defects had skin grafting after successful heat treatment. Heat treatment was not associated with marked increases in local inflammation or the development of ectopic lymphoid tissue. One and a half years after completion of treatment, all patients are relapse-free. The reusable phase change materialâbased heat application device appears perfectly suited for use in remote Buruli ulcerâendemic areas of countries with limited resources and infrastructure
Airway hyperresponsiveness, but not airway remodeling, is attenuated during chronic pulmonary allergic responses to Aspergillus in CCR4â/â mice
The role of CC chemokine receptor 4 (CCR4) during the development and maintenance of Th2type allergic airway disease is controversial. In this study, we examined the role of CCR4 in the chronic allergic airway response to live Aspergillus fumigatus spores, or conidia, in A. fumigatussensitized mice. After the conidia challenge, mice lacking CCR4 (CCR4â/â mice) exhibited significantly increased numbers of airway neutrophils and macrophages, and conidia were more rapidly eliminated from these mice compared with control CCR4 wildâtype (CCR4+/+) mice. Significant airway hyperresponsiveness to intravenous methacholine was observed at day 3 in CCR4â/â mice, whereas at days 7 and 30, airway hyperresponsiveness was attenuated in these mice compared with control mice. A major reduction in peribronchial and airway eosinophilia was observed in CCR4â/â mice at all times after conidia challenge in contrast to CCR4+/+ mice. Further, whole lung levels of interleukin (IL) 4 and ILâ5 were significantly increased in CCR4â/â mice at day 3, whereas these Th2 cytokines and ILâ13 were significantly decreased at day 30 in CCR4â/â mice compared with their wildâtype counterparts. Peribronchial fibrosis and goblet cell hyperplasia were similar in both groups of mice throughout the course of this model. In summary, CCR4 modulates both innate and acquired immune responses associated with chronic fungal asthma.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154441/1/fsb2fasebj16100193-sup-0001.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154441/2/fsb2fasebj16100193.pd
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