3,995 research outputs found
Vaccinating the Young Calf with a Parenteral Adjuvanted Vaccine to Develop a Protective BRSV IgA nasal Response
Objective The purpose of this study was to evaluate the efficacy of an adjuvanted modified live virus (MLV) vaccine in the presence of well-defined maternal passive immunity.Study Description Calves were vaccinated at approximately 1 month of age and challenged ~90 days later when BRSV systemic antibodies were less than 1:4. Clinical signs, nasal secretions and blood samples for virus measurement [polymerase chain reaction (PCR) and virus isolation (VI)] and to measure for mucosal BRSV IgA antibodies were collected and the animals were euthanized and necropsied 8 days post infection. Body temperature and other clinical signs were lower at 6 and 7 days post challenge in the vaccinates. Nasal viral shed was 3–4 times lower in the vaccinated animals as measured by VI and PCR compared to the controls. On day 8 following challenge, animals were necropsied, and lung lobes were scored and tested for virus by PCR and indirect fluorescent assay (IFA). There was a 25-fold reduction in PCR virus detection in vaccinates and two of the vaccinated calves’ lungs were PCR negative. Only 29.4% of vaccinated calves were BRSV positive on IFA testing at necropsy, while 87.5% of control calves were BRSV positive. Vaccinated calves developed a mucosal BRSV IgA response with over 50% of the vaccinated calves having IgA prior to challenge and all vaccinated calves were positive following challenge
A New Dark Matter Candidate: Non-thermal Sterile Neutrinos
We propose a new and unique dark matter candidate: eV to
keV sterile neutrinos produced via lepton number-driven resonant MSW
(Mikheyev-Smirnov-Wolfenstein) conversion of active neutrinos. The requisite
lepton number asymmetries in any of the active neutrino flavors range from
10 to 10 of the photon number - well within primordial
nucleosynthesis bounds. The unique feature here is that the adiabaticity
condition of the resonance strongly favors the production of lower energy
sterile neutrinos. The resulting non-thermal (cold) energy spectrum can cause
these sterile neutrinos to revert to non-relativistic kinematics at an early
epoch, so that free-streaming lengths at or below the dwarf galaxy scale are
possible. Therefore, the main problem associated with light neutrino dark
matter candidates can be circumvented in our model.Comment: Latex 11 pages + 1 figur
The universe seen at different scales
A large-scale smoothed-out model of the universe ignores small-scale
inhomogeneities, but the averaged effects of those inhomogeneities may alter
both observational and dynamical relations at the larger scale. This article
discusses these effects, and comments briefly on the relation to gravitational
entropy.Comment: 17 pages; matches published version in Phys. Lett. A (Einstein
special issue
Physics in the Real Universe: Time and Spacetime
The Block Universe idea, representing spacetime as a fixed whole, suggests
the flow of time is an illusion: the entire universe just is, with no special
meaning attached to the present time. This view is however based on
time-reversible microphysical laws and does not represent macro-physical
behaviour and the development of emergent complex systems, including life,
which do indeed exist in the real universe. When these are taken into account,
the unchanging block universe view of spacetime is best replaced by an evolving
block universe which extends as time evolves, with the potential of the future
continually becoming the certainty of the past. However this time evolution is
not related to any preferred surfaces in spacetime; rather it is associated
with the evolution of proper time along families of world linesComment: 28 pages, including 9 Figures. Major revision in response to referee
comment
Enhancing the early student experience
This paper is concerned with identifying how the early student experience can be enhanced in order to improve levels of student retention and achievement. The early student experience is the focus of this project as the literature has consistently declared the first year to be the most critical in shaping persistence decisions. Programme managers of courses with high and low retention rates have been interviewed to identify activities that appear to be associated with good retention rates. The results show that there are similarities in the way programmes with high retention are run, with these features not being prevalent on programmes with low retention. Recommendations of activities that appear likely to enhance the early student experience are provided
Strain-Promoted Cycloaddition of Cyclopropenes with o-Quinones: A Rapid Click Reaction
Novel click reactions are of continued interest in fields as diverse as bio-conjugation, polymer science and surface chemistry. Qualification as a proper 'click' reaction requires stringent criteria, including fast kinetics and high conversion, to be met. Herein, we report a novel strain-promoted cycloaddition between cyclopropenes and o-quinones in solution and on a surface. We demonstrate the 'click character' of the reaction in solution and on surfaces for both monolayer and polymer brush functionalization
Cosmological Constraints on Bulk Neutrinos
Recent models invoking extra spacelike dimensions inhabited by (bulk)
neutrinos are shown to have significant cosmological effects if the size of the
largest extra dimension is R > 1 fm. We consider effects on cosmic microwave
background anisotropies, big bang nucleosynthesis, deuterium and Li-6
photoproduction, diffuse photon backgrounds, and structure formation. The
resulting constraints can be stronger than either bulk graviton overproduction
constraints or laboratory constraints.Comment: matches published versio
Limits on Active-Sterile Neutrino Mixing and the Primordial Deuterium Abundance
Studies of limits on active-sterile neutrino mixing derived from big bang
nucleosynthesis considerations are extended to consider the dependance of these
constraints on the primordial deuterium abundance. This study is motivated by
recent measurements of D/H in quasar absorption systems, which at present yield
discordant results. Limits on active-sterile mixing are somewhat relaxed for
high D/H. For low D/H (), no active-sterile neutrino
mixing is allowed by currently popular upper limits on the primordial He
abundance . For such low primordial D/H values, the observational inference
of active-sterile neutrino mixing by upcoming solar neutrino experiments would
imply that has been systematically underestimated, unless there is new
physics not included in standard BBN.Comment: 10 pages + 2 figures, uses revtex macros, submitted to Phys. Rev. D.
Corrected figure captions and an added referenc
Serious Gaming and Gamification interventions for health professional education
This is the protocol for a review and there is no abstract. The objectives are as follows: To evaluate the effectiveness of Serious Gaming and Gamification interventions for delivering pre- and post-registration health professional education compared with traditional learning, other types of eLearning, or other Serious Gaming and Gamification interventions. We will primarily assess the impact of these interventions on students' knowledge, skills, professional attitudes and satisfaction
'Protestantism' as a historical category
The term ‘Protestant’ itself is a historical accident, but the category of western Christians who have separated from Rome since 1517 remains a useful one. The confessionalisation thesis, which has dominated recent Reformation historiography, instead posits the two major Protestant confessions and Tridentine Catholicism as its categories, but this can produce a false parallelism in which the nature of the relationship between the confessions is oversimplified. Instead, this paper proposes we think of a Protestant ecosystem consisting of self-consciously confessional Lutheranism, a broad Calvinism which imagined itself as normative, and a collection of radical currents much more intimately connected to the ‘magisterial’ confessions than any of the participants wished to acknowledge. The magisterial / radical division was maintained only with constant vigilance and exemplary violence, with Calvinism in particular constantly threatening to bleed into radicalism. What gives this quarrelsome family of ‘Protestants’ analytical coherence is neither simple genealogy nor, as has been suggested, mere adherence to the Bible: since in practice both ‘radical’ and ‘magisterial’ Protestants have been more flexible and ‘spiritual’ in their use of Scripture than is generally allowed. It is, rather, the devotional experience underpinning that ‘spiritual’ use of the Bible, of an unmediated encounter with grace
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